Mission Name: STS-72 (74)
  Endeavour (10)         
  Pad 39-B (35)
  74th Shuttle Mission
  10th Flight OV-105
  Night Launch (12)
  KSC Landing(28)
  Night Landing (8)  
  Spacewalk 

 NOTE: Click Here for Countdown Homepage

Crew:
  Brian Duffy (3), Commander
  Brent W. Jett (1), Pilot
  Leroy Chiao (2), Mission Specialist
  Daniel T. Barry (1), Mission Specialist
  Winston E. Scott (1), Mission Specialist
  Koichi Wakata (1), Mission Specialist

Milestones:
     OPF -- Sept. 18, 1995 (Reference KSC Shuttle Status 9/18/1995)  
     VAB -- Nov. 30, 1995 (Reference KSC Shuttle Status 12/1/1995) 
     PAD -- Dec. 6, 1995 (Reference KSC Shuttle Status 12/6/1995)

  (Reference KSC Shuttle Status Jan 1996)

Payload:
  SFU Retrieval, SPARTAN/OAST-FLYER, SSBUV-8, EDFT-03, SLA-01/GAS(5), VDA-2, NIH-R3, STL/NIH-C,PBE,TES-2, CPCG

Mission Objectives:
  The primary objective of the STS-72 mission is to capture and return
to Earth a Japanese microgravity research spacecraft known as 
Space Flyer Unit (SFU).  The 7,885lbs SFU spacecraft was launched by Japan's 
National Space Development Agency (NASDA) from Tanegashima Space Center in 
Japan at 8:01 UT on March 18, 1995 aboard a Japanese H-II rocket (HII-3).  

  The STS-72 mission will also deploy (for about 50 hours) and then retrieve 
the Office of Aeronautics and Space Technology Flyer (OAST-Flyer) spacecraft.
OAST-Flyer is the seventh in a series of missions aboard reuseable
free-flying Spartan carriers. It consists of four experiments: 
Return Flux Experiment (REFLEX), 
Global Positioning System Attitude Determination and Control Experiment 
(GADACS), Solar Exposure to Laser Ordnance Device (SELODE) and the 
University of Maryland Spartan Packet Radio Experiment (SPRE).

  Other experiments onboard STS-72 include the Shuttle Solar Backscatter 
Ultraviolet Experiment (SSBUV-8) (previously flown on STS-34, STS-41, STS-43, 
 STS-45, STS-56, STS-62 and STS-66), EDFT-03, Shuttle Laser Altimeter Payload
(SLA-01/GAS(5)), VDA-2, National Institutes of Health NIH-R3 Experiment, 
Space Tissue Loss Experiment (STL/NIH-C), Pool Boiling Experiment (PBE) 
(hardware previously flown on STS-47, STS-57 and STS-60) and the 
Thermal Energy Storage (TES-2) experiment (previously flown on STS-69).  

  Get Away Special payloads include the United States Air Force
Academy G-342 Flexible Beam Experiment (FLEXBEAM-2), Society of
Japanese Aerospace Companies' G-459 - Protein Crystal Growth
Experiment and the Jet Propulsion Laboratory GAS Ballast Can with
Sample Return Experiment.

 Endeavour's 10th flight also includes two 6.5 hour spacewalks by
three astronauts to test hardware and tools that will be used in the
assembly of the International Space Station starting in late 1997.
EVA-1 on flight day five consists of Crewmembers Leroy Chiao (EV1) and
Dan Barry (EV2) while EVA-2 on Flight Day 7 consists of Leroy Chiao
(EV1) and Winston Scott (EV2).

Launch:  
  Launch  January 11, 1996 at 4:41:00.072 EST (23 min into the beginning of
the window).  Launch window was 49 min 30sec and extended until 5:07:30 a.m. 
EST.  The exact length of the window was calculated based on the location of 
the Japanese Space Flyer Unit prior to launch. (Reference KSC Press Release 1-96).  Transoceanic Abort Site (TAL) was at Ben Guerir, Morocco.

  The countdown started on time at 7:30 am in Firing Room 1 of the
Launch Control Complex (LCC) at the T-43 hour mark.  The astronaut
crew landed at the Shuttle Landing Facility at 9:30am on 1/8/96
(Reference KSC Shuttle Status 1/08/1996).  The countdown included 25 hours
and 48 minutes of built-in holds. (Reference KSC Press Release 2-96).  
The countdown went smoothly with only a few minor facility or
Ground Servicing Equipment (GSE) problems.  Noise was noted on a UPS fan 
and oil bearing temperature on LOX Pump 126 ran slightly higher than
expected.  No corrective action was necessary.  Just before the hold at
the T-20 minute mark, the Space Shuttle Main Engines (SSME) were running a 
little cool so GN2 flow was adjusted. There were also some communications
problems that caused minor launch delays, one with MILA and one with 
the new JSC front end processor.  MILA switched to a backup system and 
JSC switched to the old front end processor system.

Orbit:
  Altitude:  250 nm (288 statute miles)
  Inclination:  28.45 degrees
  Orbits:  142
  Duration:   8 days,  22 hours, 01 minutes,  47 seconds. 
  Distance:  3.7 million miles

Hardware:
  SRB: BI-077
  SRM:
  ET :  SN-75
  MLP : 
  SSME-1: SN-2028
  SSME-2: SN-2039
  SSME-3: SN-2036

Landing:  
  KSC, Saturday, January 20, 1996 2:41:41 A.M. EST Runway 15 (southwest
to northeast).  Sonic Booms heard at KSC at 2:39 A.M. EST while
Endeavour was at 26,000ft.  At 16,000 ft, Endeavour was 8nm from
the Shuttle Landing Facility and traveling at 400 miles per hour.  
At 2:41 A.M. EST, Endeavour was at 9,000ft and 5 nm.  Preflare was
done at 700ft altitude.  Unofficial Main Gear touchdown at 2:41:41 AM 
EST, (MET 8 days, 22 hrs, 00 min, 41 sec).  Nose wheel touchdown at
2:41:54 AM EST (MET 8 days 22 hrs 00 min 54sec) and wheels stop
at 2:42:47 (MET 8 days 22 hrs 01min 47 sec).  KSC Weather conditions
at the time of landing were acceptable (Reference KSC Weather History 01/20/1996 0200).
 
  Two landing opportunities were available for Saturday at the Kennedy
Space Center for Endeavour's homecoming. The first opportunity was used
which called for a firing of Endeavour's braking rockets at 12:41 a.m. 
Saturday and a touchdown on Runway 33 at the Shuttle Landing Facility. 
The second landing opportunity was not needed but would have been 
about one hour and a half later with a landing at 4:17 a.m. EST.  

Mission Highlights:

  STS-72 Flight Day 1 Highlights:

 On Thursday, January 11, 1996, 6:30 a.m. CST, STS-72 MCC Status Report #01
reports: 

  Endeavour lit up the Florida sky as it rocketed into orbit at 3:41
a.m. CST today on a Japanese satellite retrieval mission. The launch
was delayed 23 minutes due to communication configuration problems
between the Mission Control Center in Houston and ground control
stations near the launch site. The problems were quickly resolved and
Endeavour embarked on its 10th flight and the first flight of the new
year. Today's launch also marked the 74th shuttle launch in the
program's history.

  At launch time, the Japanese Space Flyer Unit satellite was over
central Australia, about 7,961 nautical miles ahead of Endeavour. The
six member crew is expected to grapple and capture the satellite early
Saturday morning.

  Once on orbit, the astronauts began to configure Endeavour for
on-orbit operations. The shuttle's payload bay doors were opened
about 90 minutes into the flight, followed by a 'go' for
on-orbit operations from flight director Jeff Bantle.

  During the nine day mission, the international crew will retrieve the
SFU, a science satellite launched by the Japanese last
March. Additionally, the crew will deploy and retrieve a second
spacecraft carrying NASA-sponsored experiments. Later in the mission
crew members Dan Barry, Leroy Chiao and Winston Scott, will conduct
two six-hour spacewalks to test tools and procedures that will be used
in the assembly and maintenance of the International Space Station.

  The astronauts will begin an eight-hour sleep period at 11:11
a.m. CST, and will receive a wake-up call from Mission Control at 7:11
p.m. today to begin their first full day on orbit.  All systems on
board Endeavour are performing well with the shuttle traveling around
the Earth in a 246 x 95 nautical mile orbit.

 On Thursday, January 11, 1996, 5 p.m. CST, STS-72 MCC Status Report #02
reports:

  After a flawless launch, Endeavour is well on its way toward the
first primary objective of its flight -- the retrieval on Saturday of
the Japanese Space Flyer Unit satellite and its cargo of long-term
space experiments.

  The crew -- Commander Brian Duffy, Pilot Brent Jett and Mission
Specialist Leroy Chiao, Winston Scott, Koichi Wakata and Dan Barry --
set up shop in orbit early today and checked out systems that will be
used during the SFU retrieval. Wakata put the shuttle's mechanical arm
through its paces in a thorough check out, finding all of the
equipment in good shape. Duffy checked out the aft cockpit controls he
will use to rendezvous with the satellite and found them ready and
able as well.

  The crew also activated many of the secondary experiments aboard
Endeavour, including the Get-Away Special packages in the cargo bay,
the Shuttle Laser Altimeter and the Commercial Protein Crystal
Growth. Duffy also completed the first in the series of engine firings
that, during the next two days, will culminate in Endeavour's
rendezvous with the SFU.

  The small engine firing slightly raised the low point of Endeavour's
orbit, adjusting the rate at which the shuttle is closing in on the
satellite. At 5 p.m. CST, Endeavour was trailing the SFU by about
8,100 nautical miles, continuing to close in at a rate of more than
750 nautical miles with each 90 minute orbit of Earth.

  The crew began an eight-hour sleep period at 11:11 a.m. CST and will
awaken for Day 2 of STS-72 at 7:11 p.m. CST. The Johnson Space Center
newsroom will be closed from 5 p.m. to 11 p.m. CST today. Mission
commentary on NASA Television will resume at crew wakeup.

  STS-72 Flight Day 2 Highlights:

 On Friday, January 12, 1996, 5 a.m. CST, STS-72 MCC Status Report #03
reports: 

  Endeavour's six astronauts spent their first full day in orbit
activating secondary experiments and checking out the spacesuits they
will wear next week during a pair of 6 1/2 hour spacewalks.

  Commander Brian Duffy, Pilot Brent Jett and Mission Specialists
Leroy Chiao, Winston Scott, Koichi Wakata and Dan Barry were awakened
at 7:11 Central time Thursday night to the music from the motion
picture "Star Wars." At the time the astronauts were awakened,
Endeavour trailed the Japanese Space Flyer Unit satellite by about
6600 nautical miles and was closing the distance between itself and
the 4-ton science satellite by about 762 nautical miles per orbit.

  Wakata is scheduled to use Endeavour's 50-foot long robot arm early
Saturday to retrieve the SFU, which was launched on March 18, 1995
atop a Japanese H-2 rocket from the Tanageshima Space Center in Japan
for 10 months of materials science studies and biological
experiments. Flight controllers reported that the SFU, which is
orbiting at an altitude of about 257 nautical miles, is in good shape
despite the loss of two jet thrusters which are part of the reaction
control system for the satellite. The thruster problem will not affect
the SFU's retrieval.

  Japanese engineers at the Sagamihara Control Center south of Tokyo
turned off the satellite's major thruster system overnight as planned,
one of the final major events prior to the SFU retrieval Saturday.

At 1:38 AM this morning, Duffy and Jett conducted a brief firing of
the orbiter's reaction control system jets to alter Endeavour's
orbit slightly and to avoid a close encounter with an orbiting Air
Force satellite nicknamed MISTY (MSTI). The satellite was launched in
May 1994 from California's Vandenberg Air Force Base on a Scout
rocket, but is no longer active. Without the maneuver, Endeavour would
have passed within 8/10 of a mile of the satellite. With the maneuver,
Endeavour remained more than 5 miles away from MSTI.

  Near the end of their workday, Chiao, Barry and Scott tested the the
three spacesuits they will wear during their two spacewalks, making
sure that the various systems in the suits were working
properly. Chiao and Barry will conduct the first spacewalk starting
Sunday night. Chiao will be joined by Scott Tuesday for the second
excursion into Endeavour's cargo bay. Both spacewalks are designed to
test tools and techniques for the assembly of the international Space
Station.

  The crew will begin an eight-hour sleep period at 10:41 AM Central
time and will be awakened early this evening for the start of the
final phase of the rendezvous to capture the Space Flyer Unit.
Endeavour is orbiting the Earth every 90 minutes at an altitude of 287
statute miles with all of its systems in excellent shape.

 On Friday, January 12, 1996, 5 p.m. CST, STS-72 MCC Status Report #04
reports:

  A day of preparation for events to come concluded aboard Endeavour
this morning, and Endeavour is now on course for the planned retrieval
early Saturday of the Japanese Space Flyer Unit satellite.

  Following an orbit-raising burn early this morning, Endeavour is now
less than 300 statute miles from the SFU and closing in on the
satellite at a little over 60 statute miles per orbit.  The crew began
an eight-hour sleep period at 10:41 a.m. CST and will awaken for Day 3
of the mission at 6:41 p.m. CST today.

  During their second day in space, Pilot Brent Jett and Mission
Specialist Koichi Wakata performed a survey of Endeavour's cargo bay
using the shuttle's robot arm, finding everything in excellent
shape. Also, astronauts Leroy Chiao, Winston Scott and Dan Barry
checked out the spacesuits and spacewalking gear they will use later
in the flight to perform two spacewalks. All three suits were found to
be in good condition. Chiao and Barry are planned to conduct the first
spacewalk starting on Sunday night. Chiao will be joined by Scott on
Tuesday for the second excursion into Endeavour's cargo bay. Both
spacewalks will test tools and techniques for the assembly of the
international Space Station.

  For Day 3, the primary objective will be the capture and berthing of
the SFU. Rendezvous operations will begin in earnest at about 12:44
a.m. CST Saturday as Endeavour, then eight nautical miles from the
SFU, starts the Terminal Initiation burn to close the final distance
to the satellite. As Endeavour approaches the final half-mile,
Commander Brian Duffy will begin manually flying the shuttle. Wakata
is planned to capture the SFU using the robot arm at about 3:24
a.m. CST Saturday.

  The SFU was launched on March 18, 1995 atop a Japanese H-2 rocket
from the Tanageshima Space Center in Japan for 10 months of materials
science studies and biological experiments.

  STS-72 Flight Day 3 Highlights:

 On Saturday, January 13, 1996, 6 a.m. CST, STS-72 MCC Status Report #05
reports: 

   Mission Specialist Koichi Wakata used Endeavour's robot arm to
retrieve the Japanese Space Flyer Unit satellite at 4:57 a.m. central
time completing its 10-month scientific voyage and the primary
objective of the first Shuttle mission of the year. Berthing of the
SFU was completed at 5:39 a.m. as Endeavour passed southeast of
Madagascar.

   The retrieval followed jettison of both solar arrays when sensors
indicated the panels did not latch properly against the satellite
after being retracted.  The jettison procedure was trained for
preflight as a contingency in the event of just such an occurence.
The cannisters housing the arrays were jettisoned 12 minutes apart --
at 3:35 and 3:47 this morning -- as Endeavour and the SFU traveled
across Africa on the thirtieth orbit of the STS-72 mission.

   The contingency procedure delayed the capture of the satellite by
about an hour and half from its originally scheduled 3:26
a.m. retrieval.  The SFU was placed on internal battery power prior to
the solar array retraction activity giving it four hours of electrical
power.  Once in Endeavour's payload bay, the satellite's internal
batteries were bypassed following connection of a remotely operated
electrical cable to the side of the satellite.

   Wakata grappled the SFU satellite following a flawless rendezvous to
catch the 4-ton spacecraft. Commander Brian Duffy flew Endeavour
during the final phase of the rendezvous from the Shuttle's aft
flight deck controls, moving the orbiter to within a few feet of the
SFU allowing Wakata to attach the robot arm to the satellite's
grapple fixture.  Endeavour was orbiting the Earth over the Gulf of
Mexico near the western tip of Cuba at an altitude of about 290
statute miles at the time of the retrieval.

   The retrieval of SFU capped off 10 months of scientific investigations
involving almost a dozen experiments ranging from materials science to
biological studies.  The satellite was launched on March 18, 1995
aboard a Japanese H-2 rocket from the Tanegashima Space Center in
Japan.

   The astronauts were awakened last night by a traditional Japanese
song, "Sea in Springtime", in honor of the retrieval of the Space
Flyer Unit. The astronauts will begin an eight-hour sleep period at
10:41 this morning and will wake up tonight at 6:41.  The crew's
fourth day in space will be highlighted by the deployment of a NASA
science satellite called the OAST-Flyer.  The satellite will be
retrieved later in the flight.

  STS-72 Flight Day 4 Highlights:

 On Sunday, January 14, 1996, 6 a.m. CST, STS-72 MCC Status Report #06
reports: 

  Using Endeavour's robot arm for the second time in as many days,
Mission Specialist Koichi Wakata released a NASA satellite into orbit
this morning for two days of free- flying scientific investigations.

  The OAST-Flyer was deployed by Wakata at 5:32 a.m. Central time as
Endeavour crossed the equator just east of South America. Within
minutes, Commander Brian Duffy and Pilot Brent Jett backed Endeavour
away from the 2600-pound satellite.

  The OAST-Flyer contains four experiments that will study spacecraft
contamination, the use of the Global Positioning System for spacecraft
attitude control, laser-initiated pyrotechnic devices in the
environment of space, and an amateur radio experiment to allow radio
operators on the ground to track the satellite.

  The satellite will operate about 45 nautical miles from Endeavour
during its two days of freeflight, awaiting its retrieval Tuesday to
complete the second satellite capture of the mission.

  Prior to the satellite's release, crewmembers Leroy Chiao and Dan
Barry inspected a host of tools they will use during the first of two
6 1/2 hour spacewalks Sunday night to practice methods for the
assembly of the International Space Station. That spacewalk is
scheduled to begin about 11:30 p.m. Central time.

  Winston Scott spent most of his day conducting secondary experiments
in the Shuttle's middeck before assisting in the deployment of the
OAST-Flyer.

  This morning, flight controllers monitored colder than expected
temperatures observed on a fuel line of the Japanese Space Flyer Unit
satellite. The concern was for the potential of a hydrazine leak if
the fuel lines froze.  It appears that the fuel line thermostats are
working properly and maintaining reaction control system temperatures
at acceptable levels.

  At the time of crew wakeup, the two solar panels which were jettisoned
from the Space Flyer Unit prior to its retrieval Saturday were more
than 5300 nautical miles behind Endeavour, seperating from the shuttle
at a rate of 830 nautical miles with every orbit of the Earth.

  STS-72 Flight Day 5 Highlights:

 On Monday, January 15, 1996, 7 a.m. CST, STS-72 MCC Status Report #07
reports: 

  Astronauts Leroy Chiao and Dan Barry spent more than six hours in
Endeavour's cargo bay this morning, conducting the first of two
spacewalks on the STS-72 mission to test tools and techniques which
may be used in the construction of the International Space Station.

  With Winston Scott acting as the spacewalk coordinator from the aft
flight deck, Chiao and Barry floated out of Endeavour's airlock at
11:35 Sunday night to begin the 31st spacewalk in Shuttle history.

  After taking a few minutes to acclimate themselves in the payload bay,
first-time spacewalkers Chiao and Barry attached a portable work
platform to the end of the robot arm, operated by Pilot Brent Jett and
Mission Specialist Koichi Wakata.  Jett used the arm to grapple
various pieces of hardware designed to hold large modular components,
mimicking the way equipment boxes and avionics gear will be moved back
and forth in assembling the Space Station.

  Chiao and Barry unfolded a cable tray diagonally across the forward
portion of the cargo bay housing simulated electrical and fluid lines
similar to those which will connect modules and nodes of the Space
Station.  The rigid umbilical, as it is known, was tested for its ease
of handling and the ability of the astronauts to hook up the lines to
connectors on the side of Endeavour's bay.

  While Chiao unraveled various lengths of cable from a caddy device,
Barry spent time practicing the hookup of the various cables in the
rigid umbilical to connectors in the bay, testing his ability to
manipulate tiny bolts and screws in weightlessness.  He reported that
most tasks could be accomplished with little difficulty.  Barry and
Chiao then traded places, as Barry mounted the portable work platform
to evaluate its worth.

  The astronauts stayed ahead of their timeline throughout the night,
finally concluding their spacewalk at 5:44 Monday morning.  In all,
Chiao and Barry spent six hours and nine minutes in the cargo bay.

  Throughout the spacewalk, flight controllers kept tabs on the
temperature of thruster fuel lines in the Japanese Space Flyer Unit
satellite, which was retrieved Saturday by Wakata.  Fluctuating
temperatures in the fuel lines, possibly caused by the erratic
performance of the SFU's thermostats, resulted in the development
of a series of procedures for reorientating the Shuttle to warm up the
satellite, if required, to prevent hydrazine in the thruster lines
from freezing.

  The astronauts were awakened Sunday night at 6:41 to the theme from
"Star Trek, The Next Generation."  Within hours, the astronauts began
a series of jet thruster firings to increase the distance between
Endeavour and the OAST-Flyer science satellite which Wakata deployed
Sunday.  The satellite is scheduled to be retrieved tomorrow morning.
Endeavour is orbiting the Earth every 90 minutes at an altitude of 192
statute miles with all of its systems in excellent shape.

  STS-72 Flight Day 6 Highlights:

 On Tuesday, January 16, 1996, 5 a.m. CST, STS-72 MCC Status Report #08
reports: 

  Mission Specialist Koichi Wakata extended Endeavour's robot arm
early today and plucked a NASA science satellite out of orbit to
successfully complete the second satellite retrieval of the STS-72
mission.

  The 2600-pound OAST-Flyer satellite was grappled at 3:47 a.m.,
following two days of free-flying investigations by a group of
experiments sponsored by NASA's Office of Aeronautics and Space
Technology.

  Within minutes of capturing the satellite, Wakata lowered the
OAST-Flyer onto its truss platform in Endeavour's cargo bay, just
as he did with the Japanese Space Flyer Unit following its retrieval
on Saturday.

  The capture of the OAST-Flyer culminated a textbook rendezvous
performed by Commander Brian Duffy and Pilot Brent Jett, who guided
Endeavour alongside the satellite through a series of maneuvering jet
firings.

  The satellite retrieval clears the way for the next major event of the
flight --- a six hour spacewalk by astronauts Leroy Chiao and Winston
Scott. It will be the second spacewalk for Chiao and the first for
Scott. The second spacewalk is scheduled to begin about 11 p.m.

  Chiao and Scott will conduct more tests of tools and procedures to be
incorporated in the assembly of the International Space
Station. During the spacewalk, Scott will be maneuvered away from the
payload bay on the end of the robot arm to evaluate his spacesuit's
resistance to extreme cold.

  Flight controllers, meanwhile, continue to keep an eye on one of two
components of the Shuttle's flash evaporator system, which provides
cooling for Endeavour and its associated avionics. The low-end cooling
system, called the topping evaporator, shut down early Monday because
of what is believed to be a formation of ice in the system.  Plans
currently call for another attempt to flush out the ice once the
second spacewalk is completed. Endeavour's cabin pressure will be
raised to 14.7 pounds per square inch to force warm air into the
system which could help melt the ice. The cooling system problem had
no impact on the retrieval of the OAST-Flyer and is not expected to
affect the second spacewalk. Endeavour is receiving adequate cooling
from a primary cooling system and the radiators which are deployed on
the payload bay doors.

  Endeavour is currently orbiting the Earth at an altitude of 190
statute miles, completing one orbit of the planet every 90 minutes.

  STS-72 Flight Day 7 Highlights:

 On Wednesday, January 17, 1996, 8 a.m. CST, STS-72 MCC Status Report #09
reports: 

   Astronauts Leroy Chiao and Winston Scott tested connectors, cables and
work platforms for almost 7 hours in Endeavour's cargo bay this morning
during the second spacewalk of the STS-72 mission. Shortly after the
astronauts completed their spacewalk, Endeavour's flash evaporator system 
was successfully purged and is again working at full capacity.

   Chiao and Scott floated into the bay at 11:54 p.m. Tuesday as
Endeavour passed over the African continent. The spacewalk began about
one hour later than expected as the astronauts took longer to don
their suits than had been expected.  The spacewalk concluded at 6:34
a.m., with the two astronauts logging 6 hours 53 minutes and 41
seconds working in the vacuum of space.

  Chiao and Scott worked with utility boxes, slidewires and a portable
work stanchion affixed to Endeavour's robot arm to gather
additional data on methods and procedures which may be incorporated in
the techniques which will be used to assemble the International Space
Station.

  Flight controllers had to juggle spacewalk activities throughout the
night due to the delayed start and a drop in temperature in the
thruster fuel lines on the Japanese Space Flyer Unit satellite.
Commander Brian Duffy maneuvered Endeavour to a warmer attitude
allowing SFU temperatures to increase. The maneuver slightly delayed
one of the priority tasks of the spacewalk --- a test of how well
Scott's spacesuit would repel the freezing temperatures of space.

   Late in the spacewalk, Scott finally climbed into foot restraints on
the OAST-Flyer satellite platform for the thermal evaluation
exercise. Endeavour was maneuvered to the coldest position possible,
with its payload bay facing out toward deep space and allowing
temperatures to dip to about 104 degrees below zero at the point where
Scott was positioned to test the ability of his spacesuit to repel the
bitter cold temperature of space.

  It was Chiao's second spacewalk and the first for Scott, who
choreographed the first spacewalk of the flight early Monday. Scott
traded places with Dan Barry, who acted as spacewalk coordinator
throughout tonight's EVA.

  Pilot Brent Jett and Mission Specialist Koichi Wakata worked alongside
Barry on Endeavour's aft flight deck, operating the ship's robot
arm to move Chiao and Scott about the cargo bay in support of their
various tasks.

  As Chiao and Scott began their spacewalk, flight controllers
repressurized Endeavour's cabin to 14.7 pounds per square inch to
help warm the Shuttle in an effort to dislodge ice from the ship's
flash evaporator system. The system is used to dissipate heat from the
Shuttle and its avionics in association with radiators which are
mounted on the inside of the payload bay doors.  Shortly after 7:30
a.m., the FES core was successfully purged and the system is working
at full capacity.

  Earlier, Wakata fielded questions from Japanese schoolchildren
representing Houston schools as part of a television program about the
mission which was aired in Japan.  Endeavour is currently orbiting the
Earth at an altitude of about 192 statute miles.

  STS-72 Flight Day 8 Highlights:

 On Thursday, January 18, 1996, 6 a.m. CST, STS-72 MCC Status Report #10
reports: 

   Endeavour's astronauts enjoyed a day off today as they neared the
end of their 9-day mission. Commander Brian Duffy, Pilot Brent Jett
and Mission Specialists Leroy Chiao, Winston Scott, Koichi Wakata and
Dan Barry relaxed and took in the view of Earth from orbit after
completing a full week in space and all of their mission objectives.

   The relaxed schedule for the astronauts came as the crew headed into
the homestretch of its mission, in which the Japanese Space Flyer Unit
satellite was retrieved, the NASA OAST-Flyer satellite was deployed
and retrieved and two spacewalks were conducted to test tools and
techniques for the development of the International Space Station.

   After four hours of free time, the astronauts completed some secondary
experiments in the middeck and stowed several spacewalk tools.  They
now will turn their attention to the scheduled return to Earth early
Saturday morning. Endeavour's landing is scheduled for 1:42
a.m. Saturday at the Kennedy Space Center.

   As the crew wrapped up its day, Duffy, Scott and Wakata took time out
to discuss the progress of the flight with South African students in
Johannesburg as part of the United States Information Agency's
"Worldnet" program.

  The astronauts will begin an 8-hour sleep period at 9:11 a.m.  They
will awaken at 5:11 p.m., and begin a checkout of Endeavour's flight
control systems and steering jets, which will be used during the
Shuttle's hour-long descent back to Earth.  Endeavour is orbiting the
Earth every 90 minutes at an altitude of 192 statute miles. All of the
ship's systems are functioning normally.

  STS-72 Flight Day 9 Highlights:

 On Friday, January 19, 1996, 6 a.m. CST, STS-72 MCC Status Report #11
reports: 

  With all mission objectives accomplished, Endeavour's astronauts
packed up their ship for its return trip back to Earth on
Saturday. Endeavour is scheduled for a 1:42 a.m. CST landing at the
Kennedy Space Center.

  Two landing opportunities are available Saturday at the Kennedy Space
Center for Endeavour's homecoming. The first calls for a firing of
Endeavour's braking rockets at 12:41 a.m. Saturday resulting in a
1:42 a.m. touchdown on Runway 33 at the Shuttle Landing Facility. The
second landing opportunity is about one hour and a half later.
Weather conditions are predicted to be acceptable to support landing
in Florida.

  The crew's sleep period lasts from 9:11 a.m. to 5:11 p.m., when the
astronauts will be awakened to begin deorbit preparations. Endeavour's
cargo bay doors are scheduled to be closed about 10 p.m.

  In preparation for tomorrow's return home, Commander Brian Duffy
and Pilot Brent Jett tested Endeavour's flight control systems and
aerosurfaces by activating one of three hydraulic power units.  Duffy
also cycled the ship's rudder, speed brake and elevons and
test-fired the Shuttle's 44 steering jets to validate their
health. Two of the jets failed, but will have no impact on the landing
since redundant jets will be selected to perform the same function.

  Duffy conducted communications checks with ground support sites in
California and Florida as crewmates Leroy Chiao, Winston Scott, Koichi
Wakata and Dan Barry stowed cabin gear and spacewalk hardware which
was used during the two spacewalks conducted during the mission.

  Earlier, the astronauts participated in a crew news conference,
which featured questions from U.S. and Japanese reporters at the
Kennedy Space Center and the Johnson Space Center.  Endeavour is
orbiting the Earth every 90 minutes at an altitude of 192 statute
miles with all of its systems functioning normally as the Shuttle
heads for the end of a 3.7 million mile mission.

  STS-72 Flight Day 10 Highlights:

 On Saturday, January 20, 1996, 3 a.m. CST, STS-72 MCC Status Report #12
reports: 

   Endeavour wrapped up the first Shuttle mission of the year in the
predawn hours this morning, swooping to an ontime landing at 1:42
a.m. central time at the Kennedy Space Center completing a 3.7 million
mile flight. It was the sixth straight Shuttle landing at the Florida
spaceport.

  Commander Brian Duffy and Pilot Brent Jett guided Endeavour to its
landing in perfect weather after firing the Shuttle's braking
rockets an hour earlier over the Indian Ocean.  During the mission,
Endeavour's six astronauts retrieved the Japanese Space Flyer Unit,
which had been launched on a Japanese rocket 10 months ago, deployed
and retrieved a NASA science satellite called the OAST-Flyer, and
conducted a pair of spacewalks to test tools and refine techniques for
the assembly of the International Space Station.

  About an hour after landing, Endeavour's crewmembers left the
Shuttle, inspecting the vehicle in the cool Florida nighttime air.
The astronauts will return to Ellington Field in Houston later today,
with arrival expected sometime about Noon.

<end of mission>

Mission Name: STS-75 (75)
  Columbia (19)         
  Pad 39-B (36)
  75th Shuttle Mission
  19th Flight OV-102
  KSC Landing (29)

 NOTE: Click Here for Countdown Homepage

Crew:
  Andrew M. Allen (3), Commander
  Scott J. Horowitz (1), Pilot
  Franklin R. Chang-Diaz (5), Payload Commander
  Maurizio Cheli (1), Mission Specialist (ESA)
  Jeffrey A. Hoffman (5), Mission Specialist
  Claude Nicollier (3), Mission Specialist (ESA)
  Umberto Guidoni (1), Payload Specialist (Italy)
 
Milestones:
     OPF -- Nov 05, 1995 (Reference KSC Shuttle Status 11/06/1995)  
     VAB -- Jan 23, 1996 (Reference KSC Shuttle Status 1/24/1996)  
     PAD -- Jan 29, 1996 (Reference KSC Shuttle Status 1/29/1996)
     FRR -- Feb 09, 1996 (Reference KSC Press Release 18-96)

  (Reference KSC Shuttle Status Feb 1996)

Payload:
  TSS-1R, USMP-03 (SAMS,MEPHISTO,AADSF,ZENO,IDGE), OARE, CPCG, MGBX (CSD,FFFT, RITSI) 

Mission Objectives:
  The primary objective of STS-75 is to carry the 
Tethered Satellite System Reflight (TSS-1R) into orbit and to deploy 
it spaceward on a conducting tether.  The mission will also fly the 
United States Microgravity Payload (USMP-3) designed to investigate 
materials science and condensed matter physics.

 The TSS-1R mission is a reflight of TSS-1 which was flown onboard
Space Shuttle Atlantis on STS-46 in July/August of 1992.  During that
flight, the tether was deployed a distance of 860 feet.  STS-75
mission scientist hope to deploy the tether to a distance of over 12
miles (20.7km).

  The Tether Satellite System will circle the Earth at an altitude
of 296 kilometers which will place the tether system within the
rarefied electrically charged layer of the atmosphere known as the
ionosphere.  The conducting tether will generate high voltage and
electrical currents as it moves through the ionosphere across
the magnetic field lines of the earth.  Scientists will be able
to learn more about the electrodynamics of a conducting tether
system to deepen our understanding of physical processes in the
near-Earth space environment.  These studies will help provide
explanations for events such as the formation and behavior of
comet tails and bursts of radio "noise" detected from other
planets.

  The specific TSS1-R mission objectives are:   characterize the 
current-voltage response of the TSS-orbiter system, characterize
the satellites high-voltage sheath structure and current collection
process, demonstrate electric power generation, verify tether 
control laws and basic tether dynamics, demonstrate the effect
of neutral gas on the plasma sheath and current collection, characterize
the TSS radio frequency and plasma wave emissions and characterize the
TSS dynamic-electrodynamic coupling.

  TSS-1R Science Investigations include:  TSS Deployer Core Equipment
and Satellite Core Equipment (DCORE/SCORE), Research on Orbital Plasma
Electrodynamics (ROPE), Research on Electrodynamic Tether Effects (RETE),
Magnetic Field Experiment for TSS Missions (TEMAG), Shuttle Electrodynamic
Tether System (SETS), Shuttle Potential and Return Electron Experiment
(SPREE), Tether Optical Phenomena Experiment (TOP), Investigation of
Electromagnetic Emissions by the Electrodynamic Tether (EMET), Observations
at the Earth's Surface of Electromagnetic Emissions by TSS (OESSE), 
Investigation and Measurement of Dynamic Noise in the TSS (IMDN), Theoretical
and Experimental Investigation of TSS Dynamics (TEID) and the Theory
and Modeling in Support of Tethered Satellite Applications (TMST).

  The USMP-3 payload consists of four major experiments mounted on two
Mission Peculiar Experiment Support Structures (MPESS) and three Shuttle 
Mid-deck experiments.  The experiments are: Advanced Automated
Directional Solidification Furnace (AADSF), Material pour l'Etude des
Phenomenes Interessant la Solidification sur Terre et en Orbite (MEPHISTO),
Space Acceleration Measurement System (SAMS), Orbital Acceleration
Research Experiment (OARE), Critical Fluid Light Scattering Experiment 
(ZENO) and Isothermal Dendritic Growth Experiment (IDGE).

Launch:  
  Launch February 22, 1996 3:18:00.061 pm EST. Launch window was 
2 hours 30 min. There were no unscheduled holds.  Winds at liftoff
were from approximately 63.4 degrees at 5.76 knots.  Ambient temperature
was 72.8 F, barometric pressure was 29.94in Hg and relative humidity
was at 78%.

  About four seconds after liftoff, Shuttle Commander Andy Allen
reported that his instruments showed that one of the shuttle main
engines was operating at only 45% of its normal power level.  Flight
controllers in Houston quickly responded that all engines were
performing nominally.  The engines throttled as expected about 1
minute into the launch, and operated normally all the way to main
engine cutoff at 8 and a half minutes into the flight.  Engineers will
look at data from the launch to try to understand the faulty reading.
(Reference STS-75 MCC Status Report #01)

  On Tuesday, 2/20/96, the mission management team met briefly to
discuss an incident that occurred overnight at Pad 39B.  At about 1
a.m., a neutralizing agent, believed to be sodium hydroxide was
spilled over the left-hand solid rocket booster and the left side of
the external tank.  This non-toxic liquid is used to neutralize any
potential hazardous vapors that may be present during normal
operations to remove covers off the reaction control system thrusters
on Columbia.  The incident has not seriously delayed the launch
countdown.  However, engineering evaluations are in work to determine
if any concerns exist for the liquid contacting the flight hardware.
(Reference KSC Shuttle Status 2/21/1996).

  The countdown started at 4pm EST at the T-minus 43 hour mark on 
Monday, 2/19/96 and the payload bay doors were closed.  The STS-75
crew arrived at the Shuttle Landing Facility at 3:30pm EST.
(Reference KSC Shuttle Status 2/20/1996).   

  On Tuesday, 2/13/96, a faulty wire to one of the pyrotechnic devices
at the 17-inch disconnect located between the orbiter and external
tank was replaced and tested successfully. Also, problems with the
crew hatch were resolved and final testing was successful.
(Reference KSC Shuttle Status 2/13/1996). 

  On Friday, 2/9/96,  Hypergolic loading operations took place and the
Flight Readiness Review (FRR) was conducted.  The countdown is scheduled
to begin on February 19. (Reference KSC Shuttle Status 2/09/1996). 

  On Friday, 2/2/96, work continued to remove and replace the high 
pressure fuel turbo pump from main engine number 1.  The new pump 
was installed and electrical hookup started. The Terminal Countdown 
Demonstration Test was also concluded.  (Reference KSC Shuttle Status 2/02/1996).

  On 1/29/96, the Shuttle Columbia was transferred to Pad 39B from the
Vehicle Assembly Building. First motion occurred at 2:33 a.m. The
vehicle was hard down on the pad at about 9:30 a.m.  Later that evening,
the three auxiliary power units (APU) were to be hot fired. After that,
workers will start the week long process to remove and replace the 
high pressure fuel turbo pump from Space Shuttle Main Engine (SSME) No. 1.

  On 1/23/96, Columbia was transferred to the Vehicle Assembly Building
with first motion occurring at 10:45 p.m.  From there it was lifted and
mated with external tank. The Shuttle interface verification test 
was scheduled for 1/26/96. (Reference KSC Shuttle Status 1/24/1996).
 
  On 11/27/95, work began on the removal and replacement of Window
No. 6.  The three main engines have been removed.  The forward
reaction control system removed on Tuesday 11/28/95 and the freon
coolant loop No. 1 deserviced.  Testing was started on the Ku-band 
antenna.  In the Operations and Checkout building work on the
the STS-75 payloads, Tethered Satellite and USMP-3, has been going
smoothly and is nearing completion. They will be in preparation for
final testing. (Reference KSC Shuttle Status 11/27/1995).

Orbit:
  Altitude:  160 nm (184 statute miles)
  Inclination: 28.45 degrees
  Orbits:  251
  Duration:  15 days,  17 hours, 41 minutes, 25  seconds.
  Distance:  6.5 million miles

Hardware:
  SRB: BI-078
  SRM: 360W053A(left),360W053B(right)
  ET :  SN-76
  MLP : 3
  SSME-1: SN-2029
  SSME-2: SN-2034
  SSME-3: SN-2017

Landing:  
  KSC Saturday, March 9, 1996 at 8:58:38 a.m EST, SLF Runway 33
Landing times: Main gear touchdown at MET 15days 17hours
40min 21sec, or 8:58:21 am EST.  Nose gear touchdown at MET 15days
17hours 40min 36sec, or 8:58:36 EST. Wheels stop at 15days 17hours
41min 25 sec or 8:59:25am EST.(Reference KSC Shuttle Status 3/09/1995).

  The first KSC landing opportunity for Saturday, March 9, 1996 was
waived off due to cloud cover at KSC. This would have required a
deorbit burn at 6:23am EST, with a landing at 7:24am EST.  A "go" was
given by Mission Control for the deorbit burn at 7:46am EST to support
the 2nd KSC opportunity.  Deorbit burn at MET: 15d16h37m43s on orbit
251 at 7:56am EST.  

  In the event of unacceptable weather at KSC, the shuttle would have
landed during one of 3 landing opportunities at Edwards AFB.  The
first opportunity would have been on orbit 252 with a 9:25am EST
deorbit burn leading to a landing at 10:26am EST (7:26am Dryden time).

  On 3/9/96, flight controllers opted to forego KSC landing
opportunities at 7:16 a.m., 8:52 am EST and 10:27 on because of
forecast low clouds and the possibility of rain and gusty winds.
Weather conditions did not inprove and at 9:25am EST, mission
controllers waived off KSC's final landing opportunity for 3/8/96.
(Reference STS-75 MCC Status Report #28)

Mission Highlights:

  About four seconds after liftoff, instruments showed that one
Space Shuttle Main Engine (SSME) was operating at only 45% of normal
power.  It was quickly determined that the problem was in the
instrumentation and not in the engine.  Over the next few days, t
he TSS-1R and USMP-3 payloads were powered up and prepared for
science operations.  Problems were noted with a payload interface
device known as a "Smart Flex".  The deployment of the TSS satellite
was delayed 24 hours to perform additional testing on the device.  On
Flight Day 4 (2/25/95), deploy operations began at 2:45pm CST.  At
approximately 7:30pm CST, after TSS-1R had deployed 19.7km of tether and
had almost reached full deployment, the tether broke.  

  STS-75 Flight Day 1 Highlights:

 On Thursday, February 22, 1996, 5:30 p.m. CST, STS-75 MCC Status Report #01
reports: 

  About four seconds after liftoff, Shuttle Commander Andy Allen
reported that his instruments showed that one of the shuttle main
engines was operating at only 45% of its normal power level.  Flight
controllers in Houston quickly responded that all engines were
performing nominally.  The engines throttled as expected about 1
minute into the launch, and operated normally all the way to main
engine cutoff at 8 and a half minutes into the flight.  Engineers will
look at data from the launch to try to understand the faulty reading.

  A brief firing of the orbital maneuvering engines halfway around the
Earth placed Columbia in its operating orbit on time.  The
seven-member crew got a go for orbit operations as expected and opened
the payload bay doors to begin cooling with the radiators.

  Just before 5 p.m. Central time, astronauts Claude Nicollier and
Franklin Chang-Diaz begin activating the support equipment for the
Italian Tethered Satellite System.  Other equipment and experiments
were scheduled for their first activation later today.  On Friday,
activities with the TSS begin in earnest leading up to Saturday's
reeling out of the tethered satellite.

  STS-75 Flight Day 2 Highlights:

 On Friday, February 23, 1996, 7 a.m. CST, STS-75 MCC Status Report #02
reports:

  Setting up shop was the order of business aboard Columbia overnight
and early Friday as the seven astronauts split into three shifts to
support the many experiments scheduled throughout the 14-day mission.

  Much of the astronauts' time was spent verifying the health of the
Tethered Satellite System in anticipation of its scheduled deployment
Saturday afternoon.  The 1,400 pound satellite will be deployed to a
distance of almost 13 miles while it remains attached to its support
structure in the orbiter's payload bay by a pencil-thin cable. TSS
deployment is currently scheduled for Saturday at 2:37 p.m. Central
time.

  Before turning in for his first on-orbit sleep period, Mission
Specialist Jeff Hoffman tested the latching mechanisms that secure the
satellite atop its docking ring on an extendable boom structure.
These latches will be released just prior to the start of the six hour
process to reel out the satellite.

  The crew also checked out and activated several other experiments that
will be carried out after the Tethered Satellite is retrieved Monday.
A glovebox device on the middeck was set up and will be used later in
the flight to conduct combustion experiments in an enclosed
environment.

  The astronauts also activated the Commercial Protein Crystal Growth
experiment designed to grow nearly perfect crystals for study back on
Earth for the possible development of better pharmaceuticals.

  Columbia will remain in a near circular 160 nautical mile orbit for
most of the mission, circling the Earth every 90 minutes to provide
the crew with views of a sunrise and sunset 16 times each day.

 On Friday, February 23, 1996, 6 a.m. CST, STS-75 Payload Status Report #01
reports: (0/15:42 MET)

  Mission Specialist Claude Nicollier, Payload Commander Franklin
Chang-Diaz and Payload Specialist Umberto Guidoni started their duty
shifts by activating the Shuttle Electrodynamic Tether System (SETS),
the Deployer Core Equipment (DCORE), the Tethered Satellite System
(TSS) carriers and the TSS deployer.  The SETS investigation, by
Dr. Brian Gilchrist of the University of Michigan, will study the
electrical characteristics of the Tethered Satellite System and also
will explore the use of space tethers as science tools. The Core
experiment, by Dr. Carlo Bonifazi of the Italian Space Agency, will
demonstrate the ability of a tethered system to produce electricity.

  In addition to increasing understanding of physical processes in the
near-Earth space environment, these studies will help provide
explanations for events witnessed elsewhere in the solar system, such
as the formation of comet tails and the bursts of radio "noise"
detected from Jupiter.  Tether science research will allow scientists
to conduct unique, new types of electrical experiments and to develop
new and promising tether applications in space technology.

  Mission Specialist Jeffrey Hoffman then tested the Tethered
Satellite System reel motor assembly and the Satellite restraint
latches.  These latches, which worked very well, will release the
Tethered Satellite on Saturday, allowing the satellite to be reeled
out to its maximum deployment of twelve miles (20.7 kilometers),
making the Tethered Satellite-Shuttle system the longest electrically
conductive object ever flown in space.

  Nicollier and Chang-Diaz also checked out the Tether Optical
Phenomena (TOP) experiment and the computers associated with
deployment of the Tethered Satellite.  The experiment, conducted by
Dr. Stephen Mende of Lockheed Martin, will provide visual data that
will aid scientists in answering a variety of questions concerning the
Tethered Satellite's objectives during its flight in Earth orbit.
   
  The Marshall-managed Tethered Satellite System Reflight (TSS- 1R)
mission is a reflight of the Tethered Satellite System (TSS-1), which
was flown on the Space Shuttle in July/August 1992.  Building on the
knowledge gained on the first Tethered Satellite mission about tether
motions, the Tethered Satellite System will circle the Earth, placing
the tether well within the electrically charged layer of the
atmosphere known as the ionosphere.  There, a satellite attached to
Columbia by a thin conducting tether will be deployed into the
ionosphere from the Shuttle payload bay, providing scientists with
unique experimental opportunities.

  The United States Microgravity Payload (USMP-3), also managed by the
Marshall Space Flight Center, soon will have completed its first 24
hours in orbit, nestled safely within the confines of the Shuttle
Columbia's cargo bay.  Mission Specialist Maurizio Cheli activated the
payload's support equipment, and Chang-Diaz turned on the experiments
in the cargo bay.
 
  Following the successful power-up of the experiments onboard,
science teams located at Marshall's Spacelab Mission Operations
Control Center began remotely monitoring and interacting with the
Microgravity Payload.  The USMP-3 experiments are designed to increase
scientists' understanding of materials science and condensed matter
physics.  These experiments include the MEPHISTO directional
solidification furnace, the Advanced Automated Directional
Solidification Furnace (AADSF), the Isothermal Dendritic Growth
Experiment (IDGE) and the Critical Fluid Light Scattering Experiment,
or Zeno.

  Working in Columbia's cabin, Chang-Diaz examined the Middeck
Glovebox Facility while Nicollier activated the Commercial Protein
Crystal Growth experiment.  The glovebox, managed by the Marshall
Space Flight Center, is a contained work area where crew members will
conduct three combustion investigations that would be impractical and
potentially hazardous if performed outside the glovebox in the open
cabin environment.  These experiments include the Forced-Flow
Flamespreading Test and Comparative Soot Dynamics, developed by Kurt
R. Sacksteder and Dr. David L. Urban, both of the Lewis Research
Center, and the Radiative Ignition and Transition to Spread
Investigation, developed by Dr. Takashi Kashiwagi of the National
Institute for Standards and Testing.  The Protein Crystal Growth
investigation will process nine different proteins for the development
of new therapeutic treatments for infections, human cancers, hormone
disorders and Chagas disease.

 On Friday, February 23, 1996, 4:30 p.m. CST, STS-75 MCC Status Report #03
reports:

  Although running into tethered satellite computer problems that
remain under investigation by flight controllers and scientists,
Columbia's crew pressed ahead this afternoon with checkouts and
preparations for a Saturday deploy of the satellite.

  The tethered satellite itself was powered up and appears to be in
excellent condition.  However, activation and checkout of the
satellite-related experiments that are mounted in Columbia's cargo
bay fell behind schedule when a computer relay for data and commands
experienced problems. The Smart Flexible Multiplexer Demultiplexer
(SFMDM), or "Smartflex", as the computer relay is called, was
switched to a backup component after experiencing an apparent overload
when some of the cargo bay experiments were first powered up.

  The backup "Smartflex" equipment is working well, but controllers are
evaluating its performance for several hours before attempting to
repower the cargo bay-mounted satellite experiments and put further
demands on the unit. At this point, there is still enough time prior
to Saturday's planned 2:37 p.m. satellite deploy to reactivate
those experiments and perform all needed checkouts and fine-tuning.
Flight controllers currently plan to begin those procedures this
evening aiming toward an on-time satellite flyaway.

  In addition to the computer relay trouble, the crew reported apparent
balky processing by an onboard laptop computer used as one method of
displaying information from the satellite experiments. The Portable
General Purpose Support Computer (PGSC) was switched for a backup
laptop computer by the crew, and the data connections to the computer
ports also were switched to backup ports. However, the apparent slow
processing persisted. Flight controllers are evaluating the cause of
the trouble, and any impact it may have on the planned operations.

  The "Smartflex" must be operating for a deploy of the tethered
satellite since it provides data and commands to the satellite-related
experiments and equipment in the cargo bay.  Communications and
commanding of the satellite itself during deploy, however, is done by
a radio link to Columbia.

 On Friday, February 23, 1996, 6 p.m. CST, STS-75 Payload Status Report #02
reports: (01/03:42 MET)

  At the end of the first flight day, STS-75 crew members aboard the
Space Shuttle Columbia were continuing predeployment checkout and
activation of the Tethered Satellite System (TSS), a cooperative
venture between NASA and the Italian Space Agency.  The satellite,
attached to the Shuttle by a pencil-thin tether, is being readied for
deployment to a distance some 12.5 miles (20.7 kilometers) above the
orbiter.  This upward deployment, planned for Saturday afternoon, will
begin a series of electrodynamic investigations using the
Shuttle-tether-satellite system as it moves at 17,000 miles per hour
through Earth's magnetic field lines to produce electrical current and
voltage.

  Crew members methodically stepped through detailed troubleshooting
procedures for three of 18 TSS on-board computers.  The smart flexible
multiplexer/demultiplexer or relaying computer, called "smartflex,"
which sends crew commands to the tethered satellite and collects some
science data, experienced timing errors, causing it to automatically
switch over to its backup system.  The backup system appears to be
operating well and the timing errors of the smartflex computer are
continuing to be investigated.

  Payload Specialist Dr. Umberto Guidoni and Mission Specialist Jeff
Hoffman changed out the Data Display and Control System (DDCS), a
laptop computer that graphically displays TSS data, because it was
operating at a low performance level.  The backup computer was
successfully booted, but readings showed that it also was operating
sluggishly.  Since the smartflex and DDCS computers are linked, flight
controllers are checking to see if these problems may be related.

  When activated, the data acquisition and control assembly computer
that monitors various TSS parameters gave normal readings except for
tether length.  A reading of 76 feet (23 meters) was shown when it
should have been zero.  The system was later reset to zero and the
computer responded correctly.  This reading will be rechecked after
the boom on which the satellite is mounted is extended in preparation
for deployment.

  Meanwhile, Payload Commander Franklin Chang-Diaz continued science
activation procedures in an effort to keep the satellite deployment
timeline on track.  Science activities completed to this point include
activation of the Shuttle Electrodynamic Tether System ion and
electron sensors, as well as activation and checkout of the TSS
Deployer Core Equipment and Satellite Core Equipment hardware,
including the electron guns used to eject the tether current back into
the ionosphere at the orbiter.  Also, activation and checkout of the
satellite and its three investigations were completed.  These include:
Research on Electrodynamic Tether Effects, which measures electric
fields; Research on Orbital Plasma Electrodynamics, which measures
ions and electrons; and Magnetic Field Experiment for TSS Missions,
which measures magnetic fields.  Baseline data were collected both
about the charged particle environment of Columbia's cargo bay, as
well as the effect of dynamic "noise" produced by activities such as
thruster firings and water dumps to see how these vibrations are read
by the satellite's sensors.

  One of the unique features of this complex research flight is that
the seven-member international crew is working in three staggered
shifts instead of the normal two.  This allows the crew to operate a
suite of instruments designed to gather real-world information about
how conducting tethers might be used to generate electrical power for
spacecraft and to learn to control tethers in space.  Ground-based
researchers stationed at Spacelab Mission Operations Control also hope
to validate theories that could lead to numerous future applications
of tethers in space.  Such possibilities range from positioning
scientific research platforms downward into regions of Earth's
atmosphere that are too high for science balloons and too low for
remote sensing satellites, and to use the force created by current
flow in a tether to reboost spacecraft as their orbit decays due to
atmospheric drag, thereby saving fuel.

  Another unique feature of the tethered satellite mission is that the
science investigations all work together to give researchers an
integrated picture of system performance and to characterize the
charged particle environment in and around the Shuttle orbiter, which
acts as an integral part of the overall tethered system.  The tethered
satellite is coated with an electrically conducting paint.  The tether
that secures it to Columbia's cargo bay has a copper core and is
covered by Teflon and Kevlar, the material used in bullet- proof
vests, to shield the tether from the harsh space environment.
Scientific instruments are housed in the upper half of the satellite,
and on the Mission Peculiar Equipment Support Structure that is
attached to the Spacelab platform in the cargo bay.  Three ground
tracking stations located along the Shuttle's flight path will collect
additional science data during the tether mission.

  Meanwhile, data is being received by experiments that make up the
third United States Microgravity Payload (USMP-3), awaiting its turn
as the primary payload after TSS operations are completed.  In fact,
"the best images ever sent down" of dendrites were reported by Dr.
Martin Glicksman, principal investigator of the Isothermal Dendritic
Growth Experiment (IDGE).  Dendrites are microscopic tree-like
structures formed by molten materials as they solidify into the
familiar materials used for everyday products ranging from aluminum
cans to airplane turbine blades.

  Overnight, crew members will continue activating and calibrating TSS 
systems and experiments, and making other preparations for tomorrow's 
satellite deployment and the beginning of 20 hours of science data 
collection.

  STS-75 Flight Day 3 Highlights:

 On Saturday, February 24, 1996, 8 a.m. CST, STS-75 MCC Status Report #04
reports:

  Troubleshooting a balky experiment data relay box was the focus of
work aboard Columbia throughout Friday night and into this morning as
the astronauts and flight controllers attempted to track down the
problem and preserve their options for deploying the tethered
satellite at 2:37 this afternoon.

  Early this morning, in a methodical step-by-step process, the crew and
flight control team slowly activated several experiments individually
at first and then together trying to isolate the problem.  At about 2
a.m., all experiments were activated and data was being transferred
through the relay box to a laptop computer on the flight deck of the
orbiter and data was transmitted successfully to the ground.  The
computer relay is continuing to perform well and is not evidencing any
of the communications problems previously observed.  Mission Managers
are meeting this morning to review the system's status and make a
determination on whether to deploy TSS on time or to delay 24 hours.

  Called a Smart Flexible Multiplexer Demultiplexer, or "Smart Flex"
for short, the relay box reset itself several times and even
switched to an alternate system on occasion when it perceived it was
being overloaded by the checkout work associated with ensuring the
experiments were ready to support Tethered Satellite System
operations.

  The relay box is used as a way station for obtaining and distributing
data collected from four science experiments designed to take
measurements during the deployment, on- station, and retrieval
operations of the satellite.  The "Smartflex" must be operating
for a deploy of the tethered satellite since it provides data and
commands to the satellite-related experiments and equipment in the
cargo bay.

  Once deployed, the tethered satellite will slowly fly away from
Columbia, eventually reaching a distance of 12 miles (20 kilometers).
Communications and commanding of the satellite itself during deploy
and retrieve is done by a radio link to the Space Shuttle by ground
commands from NASA's Marshall Spaceflight Center in Huntsville,
which has overall program management for the TSS project.

  The tethered satellite will slowly be deployed to a 12 mile distance
over a five and a half hour period.  The satellite will remain "on
station" for science operations for about 24 hours.  The retrieval
process would follow with the satellite being reeled back in during
another five and half hour period.

 On Saturday, February 24, 1996, 6 a.m. CST, STS-75 Payload Status Report #03
reports:  (1/15:42 MET)

  After TSS-1R Payload Commander Franklin Chang-Diaz finished
replacing a defective cable connecting the Data Display and Control
System (DDCS) laptop computers and the smart flexible
multiplexer/demultiplexer (smartflex) computer in Columbia's cargo
bay, Mission Specialist Claude Nicollier reactivated the Tethered
Satellite Deployer Core Equipment, the Shuttle Potential and Return
Electron Experiment (SPREE) and the Shuttle Electrodynamic Tether
System (SETS).  Science teams at the Marshall Space Flight Center in
Huntsville then readied all three experiments for performing
preliminary measurements.  Currently, the satellite-carried
experiments are all operating well in preparation for Saturday's
afternoon deployment of the Tethered Satellite System (TSS- 1R).

  Earlier in the day, the smartflex computer, which sends crew
commands to the tethered satellite and collects science data,
experienced some timing errors, causing it to automatically switch to
its backup system.  The DDCS laptop computer in Columbia's cabin that
displays TSS data had also been operating sluggishly.  Ground
controllers and engineers at Marshall did intensive troubleshooting
with computers on the ground to simulate and diagnose the problem.
After determining that a defective cable had caused overloads in both
computers, they then requested Chang-Diaz to replace the faulty
connection with a spare cable.

  After complete reactivation of the Core, SETS and SPREE experiments,
the smartflex computer relay again experienced errors and
automatically switched over from its backup system, in which it had
been operating since the earlier timing errors, back to its primary
system.  The crew then worked to reconfigure the laptop computer to
restore communications and command ability to the experiments.
Chang-Diaz again disconnected the laptop cable and successfully
rebooted the computer.

  While reestablishing the link between the laptop and the smartflex,
Chang-Diaz reported that the smartflex, which acts like a data
switching box and checks the status of each experiment, again entered
a "warm start" or reset mode because it found that the SPREE
experiment had been deactivated.  Then, he again rebooted the laptop
after Nicollier had reactivated SPREE.

  After a fourth crash of the smartflex computer, Chang-Diaz then
allowed it to operate with the three experiments turned off and only
the data acquisition and control assembly (DACA) computer activated.
Ground controllers then monitored the smartflex relay box as
Chang-Diaz activated and deactivated the Core, SPREE and SETS
experiments one at a time.  After encountering no problems with any of
these experiments, he reactivated the laptop DDSC computer and
observed how it operated in conjunction with the smartflex while the
three experiments were inactive.  The smartflex, laptop and the three
experiments were then successfully operated together and continue to
function normally in preparation for the tethered satellite deployment
later this afternoon.

  The SETS investigation, by Brian Gilchrist of the University of
Michigan, is designed to study the ability of the tethered satellite
to collect electrons by determining the current and voltage of the
tethered system and measuring the resistance to current flow in the
tether itself.  The Italian Space Agency's Deployer Core Equipment,
developed by Dr. Carlo Bonifazi, will demonstrate the capability of a
tether system to produce electrical energy and allow studies to be
made of the tether's interaction with the ionosphere.  It does this by
controlling the current flowing through the tether between the
satellite and the orbiter, and by making a number of basic electrical
and physical measurements of the Tethered Satellite System.  Finally,
the SPREE experiment, conducted by David Hardy of the Department of
the Air Force, will measure the charged particle quantities around
Columbia before and during active tethered satellite operations.

  Meanwhile, Nicollier took video of Earth's horizon using the Tether
Optical Phenomena (TOP) equipment.  This experiment, conducted by
Stephen Mende of Lockheed Martin, involves the use of a camera system
with image intensifiers and special filters and will provide visual
data that will allow scientists to answer a variety of questions
concerning tether motions and optical effects generated during the
Tethered Satellite's deployment.  In particular, this experiment will
examine the high voltage sheath of electrically charged, or "ionized"
gas that will surround the satellite as it flies through Earth's
ionosphere.

  One means to control the current developed by the Tethered Satellite
System involves the use of electron accelerators which return
electrons to the ionized gas, or plasma, surrounding the orbiter.  The
interaction between these electron beams and the plasma is not well
understood.  By using the TOP images to make measurements of the
visible light radiated by the plasma, this process, and how it affects
the spacecraft, can be better understood.

  During the next twelve hours, experiment operations will be
performed as mission managers and ground controllers meet to discuss
their schedule for deploying the tethered satellite.

 On Saturday, February 24, 1996, 10:30 a.m. CST, STS-75 MCC Status Report #05
reports:

  STS-75 mission managers Saturday morning decided to delay deployment
of the Tethered Satellite by 24 hours to give flight controllers time
to gain additional confidence in the operations of a data relay that
provides satellite system information during deploy and science
operations.

  The Smart Flex data relay box has been stable since early this
morning, but mission managers wanted additional time to understand its
previously observed behavior.  The relay box had experienced several
unexpected "restarts". It has been performing without incident,
however, since early this morning.

  The 24-hour delay also gives flight controllers the opportunity to
enhance any contingency procedures that might be used in the event the
Smart Flex develops problems during the deploy operations.

  Late this afternoon, the astronauts will begin a standard
one-day-before-deploy timeline, allowing them to catch up on some
activation steps which were omitted during the compressed timeline
which would have been required if TSS were deployed as originally
scheduled this afternoon.

 On Saturday, February 24, 1996, 6 p.m. CST, STS-75 Payload Status Report #04
reports: (02/03:42 MET)

  With the decision to delay deployment of the joint NASA/Italian
Space Agency Tethered Satellite System (TSS) by one day, researchers
located at Spacelab Mission Operations Control are working around the
clock, analyzing initial data and ensuring that their instruments are
ready for full-up science operations.  The initiation of satellite
deployment, known as "flyaway," now is scheduled for around 2:45 p.m.
CST Sunday.

  TSS principal investigators and their science teams view this
adjustment of the mission timeline as an opportunity to accomplish all
their major science objectives.  Specifically, Mission Scientist Nobie
Stone, of the Marshall Space Flight Center (MSFC), pointed out that
important baseline data collection would have been sacrificed by the
rush to complete instrument activation and checkout if the satellite
deployment had not been postponed by 24 hours.

  Dr. Stone emphasized that gathering baseline measurements before
deployment is "like learning to walk before you run."  Part of this
data set reveals how the sensitive TSS scientific instruments react to
periodic thruster firings to maneuver the Shuttle and the satellite.
Today's science activities included mapping Earth's charged particle
upper atmosphere, which varies dramatically as Columbia orbits through
periods of daylight and darkness every 45 minutes.  Scientists will
use these and other predeployment background readings when they
analyze data collected during the more than 30 hours of planned TSS
science operations.

  One example of baseline data is the Joint Science Display produced
earlier today by combining measurements gathered by several TSS
instruments.  This graphical profile of the intensity of charged
particles around the Shuttle is giving scientists an indication of how
instruments may respond when the tethered satellite collects such
particles when deployed.  This display showed intense electron and ion
collection in the Shuttle's flight direction, or "ram," versus the
trailing side, known as the "wake" direction.

  Another example of baseline data is a "space weather map" produced
today by the Theory and Modeling Support of Tether (TMST) Sundial
investigation.  The map provides a global view of the plasma density
and temperature in the ionosphere at the altitude of the STS-75 orbit
(160 nautical miles).  This map is produced from a combination of
theoretical ionospheric models and measurements obtained from 30
ground-based stations around the world.

  Mission Manager Robert McBrayer, also of MSFC, said the deployment
delay "makes sense," especially since the satellite will be operating
on battery power once the umbilical that attaches it to the Shuttle's
power system is removed shortly before flyaway.  He emphasized the
satellite and its deployer, as well as the TSS experiments, have been
activated and are operating properly.  McBrayer noted that ground-
based flight controllers are using the extra time to better understand
problems that arose and to develop enhanced contingency plans for
satellite deployment.

  Essentially turning back the clock 24 hours, the crew spent the day
stepping through normal science and satellite predeployment activities
that were interrupted yesterday while they performed troubleshooting
for three on-board computers.  As part of a dress rehearsal for
satellite deployment, the crew maneuvered Columbia to the altitude for
satellite flyaway.  They also worked through a number of steps
designed to simulate the same orbital conditions and environment for
actual deployment the satellite, including lighting and lighting
angles.

  During some nighttime orbital passes, crew members worked with the
Tether Optical Phenomena Experiment (TOP), which gave a stunning view
of atmospheric air glow and auroras over the South Pole as viewed from
the flight deck's overhead window.  This is the window through which
the crew later will watch the deployed satellite.  TOP science team
members viewed live video images and sent voice commands to vary the
filters and exposure setting for better viewing.  The heart of the TOP
instrument is a hand-held low-light video camera with special filters
whose primary purpose on TSS is to observe luminescence produced by
electron beams and the interaction of the electrically charged
satellite with the local charged-particle and neutral atmosphere.  The
TOP has many advantages over similar photographic recordings made on
previous flights because it allows real-time observations of the
images seen by the orbiter crew.

  The crew also resumed calibration of on-board instruments and
electron accelerators, including one test of the Shuttle
Electrodynamic Tether System (SETS).  SETS instruments, mounted in the
cargo bay, will make measurements of tether voltage and current, as
well as background magnetic fields and plasma characteristics.  SETS
also provides one electron accelerator, known as an electron gun,
designed to propel charged particles back into the ionosphere after
they travel from the satellite, down the conducting tether, and
collect in the cargo bay.  The ejection of electrons is one step in
completing the circuit required for current to flow.

    During the next 12 hours, science data will continue to be
collected while the crew continues predeployment activities.

  STS-75 Flight Day 4 Highlights:

 On Sunday, February 25, 1996, 6 a.m. CST, STS-75 Payload Status Report #05
reports: (2/15:42 MET)

  "At this point, all of the instruments are working fine and
returning data," concluded Theory and Modeling in Support of Tether
(TMST) Principal Investigator Dr. Adam Drobot in a live interview with
WSFA-TV in Montgomery, Alabama.  "I think everybody is quite excited
that things are going very well."  Last night, data collection for the
STS-75 mission continued to take advantage of the additional science
opportunities afforded by the extra day of predeployment operations as
the crew performed science activities in preparation for this
afternoon's deployment of the Tethered Satellite System (TSS- 1R).

  These activities included observations of electrically charged, or
"ionized," gas in Columbia's environment and its interactions with
electron beams and orbiter water dumps.  This will enhance the control
and monitoring of the electrical charge on the Shuttle as it moves
through the ionosphere.  During tethered satellite deployment, the
tether's ability to form a complete circuit and generate electrical
power will be dependent on the path electrons take while traveling in
the vicinity of the orbiter's immediate environment and the satellite.
According to TSS-1R Mission Scientist Dr. Nobie Stone, the science
teams have already gathered "very interesting data" from these
investigations.

  One of the investigations involved using the Shuttle Electrodynamic
Tether Effects (SETS) experiment's Fast-Pulse Electron Guns to fire a
series of electron beams along the Earth's magnetic field lines.  It
also used the Shuttle Potential and Return Electron Experiment (SPREE)
to detect returning electrons which were reflected back into the
payload bay.  This reflection results from a variety of processes,
including scattering by neutral particles and magnetic reflection.

   Another investigation of Columbia's surroundings made use of the
orbiter's Flash Evaporator System (FES). To accomplish this
experiment, the crew participated in activating and deactivating the
orbiter's water release systems and manually operating the Shuttle's
attitude control system jets.  This provided a controlled means of
studying the distribution of neutral and charged particles in the
vicinity of the payload bay during Shuttle water dumps.

  Meanwhile, science teams at the Marshall Space Flight Center used
the SETS experiment's instruments to give measurements which related
to the ionized gas as it interacted with the water cloud.  The water
molecules in this cloud exchanged electrical charges with the
surrounding ionized oxygen and formed a ring shape which could be
easily distinguished from the ionized gas background around Columbia.
This gave scientists and crew members an idea of how the Shuttle's
environment might react to water dumps released while the tethered
satellite is deployed.

  For a third investigation of the orbiter's ionospheric surroundings,
the SETS and SPREE experiments teamed up with the Tether Optical
Phenomena (TOP), Research on Orbital Plasma Electrodynamics (ROPE) and
Research on Electrodynamic Tether Effects (RETE) experiments to study
the electron beams fired from the SETS experiment's electron gun.
Previous measurements indicated that a thin electron beam emitted from
the orbiter quickly expands in width to form a cylinder.  The
effectiveness of these electron emissions from the orbiter depends on
various factors, including the beam's direction, the local
ionosphere's density, and the orbiter's electrical potential compared
with that of the ionosphere.

  While Mission Specialist Claude Nicollier used the TOP camera to
watch the electron beams, the tethered satellite-mounted ROPE and RETE
experiments used their plasma diagnostic instruments to observe the
beams during both sunlight and darkness to obtain data.

  The RETE investigation also participated in an electromagnetic
environment calibration with the SETS instruments.  This calibration
observes low-frequency waves not produced by the tethered satellite.
Sources of these waves include interaction of the orbiter with the
ionosphere, ground-based transmitters, atmospheric lightning, orbiter
electrical machinery and electron gun firings.  Essentially, this
experiment calibrates the "background noise" that can be picked up by
tethered satellite instruments.

  The RETE experiment, led by Dr. Marino Dobrowolny of the Italian
Space Agency, will provide information about the electrical potential
of the ionized gas, or "plasma," sheath that will surround the
tethered satellite during its deployed operations.  The ROPE
investigation, led by Dr. Nobie Stone of the Marshall Space Flight
Center, is designed to study the behavior of charged and neutral
particles around the tethered satellite under a variety of conditions.
Last night, these investigations helped scientists to determine how
quickly electrons will be returned to the ionosphere to complete the
tether system's electrical circuit and allow the tethered satellite
system to generate electricity.

  During the night, the crew also reconfigured the laptop computer to
enable it to communicate with both cores of the smartflex data relay
in Columbia's cargo bay.  During the next twelve hours, actual
deployment operations for the tethered satellite will begin at 2:45
p.m., CST as the crew releases the satellite so it can be reeled out.

 On Sunday, February 25, 1996, 8:00 a.m. CST, STS-75 MCC Status Report #06
reports:

  Columbia's crew will begin the deploy sequence of the Tethered
Satellite System about 2:45 this afternoon after a one-day delay to
allow flight controllers and the astronauts additional time to
properly check out the various science instruments and equipment that
will be used throughout the two-day operation.

  The delay also gave flight controllers time to refine any
troubleshooting procedures that might be used in the event the Smart
Flex computer relay system develops problems during the deploy
operations.  The system has been operating trouble-free for more than
24 hours since being systematically checked out early Saturday
morning.

  Prior to initiating the deploy sequence, the boom supporting the
Tethered Satellite will be raised out of the payload bay to a height
of about 39 feet.  The satellite will be released from its docking
ring capture latches at the top of the boom and will slowly and
deliberately be deployed to a distance of slightly more than 12 mile
(20 kilometers) over a five and a half hour period.  The satellite
will remain 'on station' for science operations for about 22
hours.

  Retrieval of TSS would follow with the satellite being reeled back in
during another five and half hour period, stopping for additional
science data gathering at a distance of about one mile from the
Shuttle.  This second 'on station' operation is scheduled to
last for nine hours before the final retrieval and docking of the
satellite.  The entire TSS operation is scheduled to last about 48
hours.

  Communications and commanding of the satellite during deploy and
retrieve is done by a radio link to the Space Shuttle by ground
commands from NASA's Marshall Space Flight Center in Huntsville,
which has overall program management for the TSS project.

  With Columbia's systems in excellent shape, activities today are
focused on the deploy of the Tethered Satellite.  Columbia continues
to circle the Earth every 90 minutes at an altitude of 184 miles.

 On Sunday, February 25, 1996, 6:00 p.m. CST, STS-75 MCC Status Report #07
reports:

  Three and a half years after an errant bolt halted its deployment, the
Italian Tethered Satellite successfully began its journey from the
Shuttle Columbia for two days of scientific studies.

  Suspended at the end of a slim tether, the satellite's thrusters
nudged TSS away from a docking ring atop a 40-foot boom towering over
Columbia's cargo bay at 2:45 PM Central time. The satellite slowly
moved away from Columbia into the darkness of space as the astronauts
reported little oscillation in the long tether. An hour later, the TSS
had passed the distance of maximum deployment achieved on its previous
flight, 843 feet, during the STS-46 mission in the summer of 1992.

  Astronauts and ground controllers overcame previous difficulties
with data handling equipment and portable computers which had caused a
one-day delay in the deployment.  Operating on a normal timeline
today, the crew checked out the satellite and its associated systems
before extending the TSS boom above the bay like a giant tower.  After
making sure that Columbia and the TSS could communicate over radio
links, a power umbilical to the satellite was released, placing the
satellite on internal battery power. Columbia's maneuvering jets
were temporarily disabled during the TSS deployment, to avoid any
disturbances to the tether during the satellite's initial flyaway.

   TSS is expected to reach its farthest distance from Columbia,
almost 13 miles, by late this evening for more than 24 hours of
scientific studies on electromagnetic phenomena and the use of tethers
for satellite management. The satellite will begin its slow creep back
to Columbia Monday night in advance of its final retrieval and docking
back on its boom at about 12:43 PM Central time Tuesday afternoon.

  Columbia is functioning perfectly in support of TSS operations as it
orbits the Earth every 90 minutes at an altitude of about 180 statute
miles.

 On Sunday, February 25, 1996, 6 p.m. CST, STS-75 Payload Status Report #06
reports: (03/03:42 MET)

  Today marked a major milestone as the STS-75 crew aboard the Space
Shuttle Columbia began deploying the joint NASA/Italian Space Agency
Tethered Satellite System (TSS) on schedule at 2:45 p.m. CST.  The
world watched as the satellite smoothly and gently lifted from its
cradle atop the latticework boom that previously had been extended
some 40 feet (11.3 meters) out of Columbia's cargo bay.  The crew
continues carefully unreeling the satellite on its slender tether.
Mission Specialist Jeffrey Hoffman reported that "the satellite is
rock solid," an observation confirmed by downlinked telemetry being
viewed by the TSS ground crew.

  After Mission Manager Robert McBrayer of the Marshall Space Flight 
Center affirmed that his team was ready, the crew began actual 
deployment, known as "flyaway," by activating small tether-aligned 
thrusters mounted on the satellite.  It will take about 5.5 hours for 
the 12.8-mile (20.7-kilometer) tether to fully extend above the 
Shuttle.  Although not yet fully deployed, voltage is already being 
created across the copper-cored tether, and current is flowing 
through the tethered system.

  Shortly before flyaway, Mission Scientist Dr. Nobie Stone, also of 
the Marshall Center, made a final readiness check among the 12 
science teams at Spacelab Mission Operations Control.  He then gave 
the go-ahead to initiate the master timeline.  This timeline is a 
computer-controlled sequencing of science instrument activities.  One 
unique feature of this mission is the TSS investigations effectively 
work together as a single experiment to learn more about Earth's 
charged particle environment and how tethered satellites might be 
used to generate power in space.

  At full deployment, more than 22 hours of science data collection 
will begin.  During this mission phase, known as "On Station 1," 
researchers will gather the real-world information needed to verify 
theories and computer-based models for many physical processes active 
in the Earth's near-space environment and for a number of proposed 
future uses of tethers in space.  Ideas range from producing 
alternate forms of spacecraft power, to unraveling the mysteries of 
Earth's upper atmosphere by deploying instruments downward into 
regions that have not been fully explored.

  The TSS Deployer Core Equipment (DCORE) Principal Investigator Dr. 
Carlo Bonifazi, of the Italian Space Agency, reported that the DCORE 
successfully completed the first performance run at about a 3.8 mile 
(6 kilometer) tether length, generating a current of 195 milliamps, a 
level 97 times greater than the level obtained during the TSS-1 
mission.

  DCORE consists of control electronics and two electron accelerators, 
known as electron guns.  These will be used to reemit the electrical 
charge that collects on the satellite as the TSS moves through 
Earth's electromagnetic field and flows down the tether to the 
neutral environment in the cargo bay.  These electron guns, and those 
provided by the Shuttle Electrodynamic Tether System, then will eject 
these electrons back into the ionosphere, effectively continuing the 
circuit required for current to flow.

  Activities between science teams and crew members were carefully 
coordinated as final deployment preparations were completed.  
Predeployment science activities earlier in the day included 
gathering more baseline data, effectively "testing the waters" around 
the Shuttle and in its cargo bay prior to initiation of more complex 
conditions that accompany deployed operations.

  Pressure readings and profiles of the electron and ion density in the 
vicinity of the Shuttle and in its cargo bay were made by orbiter-
mounted Shuttle Potential and Return Electron Experiment instruments 
and satellite-mounted Research on Orbital Plasma Electrodynamics 
instruments.  At the time these measurements were made the Research 
on Orbital Plasma Electrodynamics experiment was still located in the 
Columbia's cargo bay.  These measurements give scientists and 
engineers a better understanding of how the shuttle-tether-satellite 
system works during full deployment operations.

  During the next 12 hours, full-up science activities are expected to
begin.

 On Sunday, February 25, 1996, 9:30 p.m. CST, STS-75 MCC Status Report #08
reports:

  The tether on the Italian Tethered Satellite broke about 7:30 p.m. CST
Sunday as the satellite was nearing the full extent of its deployment
from the Shuttle.  The satellite, which was nearing the end of its
planned 12.8 mile distance, immediately began accelerating away from
Columbia at a rapid rate as a result of normal orbital forces.  TSS is
separating from Columbia at a rate of 420 miles each 90 minute orbit.

  The tether apparently snapped near the top of the 39-foot TSS boom
in Columbia's cargo bay.  Neither the astronauts nor the Space
Shuttle were ever in any danger.

  Following the break, Mission Control asked the astronauts to record
television of the boom and broken tether for post-flight analysis.

  Flight controllers now will be determining when and how to secure
the TSS support equipment, including the deployment boom, before
moving on with other mission objectives.  Scientists and engineers
managed to gather about five hours of data on the performance of the
satellite and tether dynamics before the break.

  STS-75 Flight Day 5 Highlights:

 On Monday, February 26, 1996, 1 a.m. CST, STS-75 Payload Status Report #07
reports: (3/10:42 MET)

  The tether on the Italian Tethered Satellite System (TSS-1R)
separated at about 7:30 p.m. CST Sunday as the satellite was nearing
the full extent of its deployment from the Shuttle.  Just prior to
last evening's unexpected separation of the tether attaching the
satellite to Columbia's cargo bay, science activities aboard the
STS-75 Tethered Satellite System reflight (TSS-1R) mission had been
proceeding very smoothly, resulting in collection of about five hours
of extensive and exciting scientific data on the performance of the
satellite and tether dynamics and electrodynamics before the break.

  Tethered Satellite System science teams were able to take good
advantage of this period of deployed operations to collect data on a
variety of phenomena including the generation of electrical current as
the extended structure of satellite, tether and Shuttle circled the
Earth at approximately five miles per second.

  Soon after satellite release at 2:45 p.m. Sunday, the science
investigators began stepping through their plans for conducting
integrated science operations during the satellite-unreeling phase of
the TSS-1R mission.  Primary objectives for this phase included
characterizing relatively low-voltage operations of the tether system,
with controlled electric current flows through the tether and
associated electron gun firings from apparatuses mounted in the
Shuttle cargo bay.

  Tether voltages of as high as 3,500 volts were developed across the
tether, and current levels of approximately 480 milliamps, or nearly
half an amp were achieved, giving the science teams an indication of
results surpassing expectations.

  During deployment, science teams for the Deployer Core Equipment
(DCORE), led by Dr. Carlo Bonifazi of the Italian Space Agency,
operated their electron generators successfully completed initial
performance-evaluation runs, generating a 480 milliamp current along
the tether.  That level was nearly 200 times greater than that
obtained during the TSS-1 (STS- 46) mission, which was limited to a
much lower voltage (60 volts) by the shorter tether length.  The Core
team members reported that their equipment was performing better than
predicted by analytical models.

  It was pointed out that at the time of the break, the electrical
system had been in a passive mode with no current flow in the tether
for over four minutes.  The tether apparently separated near the top
of the 39-foot TSS boom in Columbia's cargo bay.  Neither the
astronauts nor the Space Shuttle were ever in any danger.

  The satellite, which was nearing the end of its planned 12.8 mile
distance, immediately began accelerating away from Columbia at a rapid
rate as a result of normal orbit forces.  TSS is separating from the
Shuttle at a rate of 420 miles each 90 minute orbit.  Following the
separation, Mission Control asked the astronauts to record television
of the boom and the broken tether for post-flight analysis.

  The several hours of deployed operations were summarized by Mission
Specialist Jeff Hoffman aboard Columbia, who noted "We did get a lot
of good data during the deploy."  Flight controllers now will be
determining when and how to secure the TSS support equipment,
including the deployment boom, before moving on with other mission
objectives

 On Monday, February 26, 1996, 10:00 a.m. CST, STS-75 MCC Status Report #09
reports:

  Columbia's astronauts are preparing to retract the Tethered
Satellite boom structure today after the Italian science probe
suddenly seperated from the Shuttle last night following a break in
the tether. The boom tower, upon which TSS was anchored prior to its
deployment Sunday afternoon, will be slowly lowered back into its
berthing platform once the remaining tether inside the boom is reeled
in.

  After its connecting cable seperated from Columbia last night, the
Tethered Satellite is trailing the Shuttle at a distance of more than
3,000 nautical miles this morning.

  The satellite is in an orbit about 30 miles above Columbia and the
distance between the two spacecraft continues to increase at a rate of
about 280 nautical miles with every orbit of the Earth. At the time
the tether broke, it was extended 12.2 miles from Columbia, just short
of its planned 12.8 mile fully-deployed length.

  About 32 feet of tether remains on the reel assembly inside the TSS
support boom in Columbia's payload bay. Once the tether is fully
retracted, the 39-foot boom will be restowed to its launch
configuration.  On Columbia, the astronauts this morning saved TSS
onboard computer data for post-flight analysis.

  Once the tether is retracted and the boom is restowed, the crew
members will turn their attention to the science activities involving
the U. S. Microgravity Payload.  The USMP experiments will study
various aspects of materials science investigation.

 On Monday, February 26, 1996, 5 p.m. CST, STS-75 MCC Status Report #10
reports:

  Astronauts aboard Space Shuttle Columbia today reeled back the
remaining length of tether and stowed the mast for the Tethered
Satellite System following last night's loss of the satellite.  The
crew and flight control teams spent much of the day putting TSS
equipment in a safely stowed condition and preparing for experiment
operations with the U.S. Microgravity Payload.

  The Italian Satellite unexpectedly separated from Columbia about
7:30 p.m. CST Sunday as the tether broke within the mast. No immediate
explanation for the incident was apparent and the crew and Mission
Control concentrated last night and today on gathering any data that
might be useful in discovering the cause.  NASA today named a board
chairman for the investigative body looking into the incident.
Members to the board are expected to be named within a few days.

  Following separation from Columbia Sunday, the satellite moved
rapidly away from the Shuttle into its higher orbit.  The satellite is
in an orbit about 30 miles above Columbia and the distance between the
two spacecraft continues to increase at a rate of about 280 nautical
miles with every orbit of the Earth. At the time the tether broke, it
was extended 12.2 miles from Columbia, just short of its planned 12.8
mile fully-deployed length.

  The crew members will now turn their attention to the science
activities involving the U.  S. Microgravity Payload.  The USMP
experiments will study various aspects of materials science
investigation.  The astronauts held a crew news conference today at
2:03 p.m. Central time to discuss the loss of the Tethered Satellite
and other aspects of their flight.

 On Monday, February 26, 1996, 6 p.m. CST, STS-75 Payload Status Report #08
reports: (4/3:42 MET)

  After successfully reeling in the remaining tether and stowing the
deployer boom, the STS-75 crew aboard the Shuttle Columbia resumed the
normal mission timeline.  They turned their attention to completing
post-satellite-retrieval science and starting full-up operations for
the third United States Microgravity Payload (USMP- 3).  During
USMP-3, the crew will conduct combustion science experiments in the
middeck glovebox, while crystals for high- technology electronics and
industrial metals research grow in materials processing furnaces in
the cargo bay.  Also, researchers located at Spacelab Mission
Operations Control will explore a substance as it simultaneously
exists in two states of matter, liquid and gas, to shed light
on how materials can be manipulated on Earth by looking at how they
act in microgravity.

  As part of TSS post-satellite-retrieval investigations, the Shuttle
Potential and Return Electron Experiment (SPREE) and Shuttle
Electrodynamic Tether System (SETS) continued making measurements of
the plasma environment in the Shuttle's cargo bay.  The crew
maneuvered Columbia into position for both instruments to gather more
information about the composition of the upper atmosphere in the
Shuttle's wake, similar to that of a boat moving through water.  In
addition to supersonic wakes produced by the orbiter, the payload bay
often houses structures that form their own wake, adding to the
complexity of the environment surrounding the system.  Since wake
profiles are difficult to accurately predict, especially at the edges,
SETS mapping will enhance future missions.

  Relecting over the activities of the past 24 hours, Mission Manager
Robert McBrayer confirmed that a good deal of data is "in the bank"
and reported that ground crews are gathering evidence to determine
what happened to cause the tether to break.  He added that "everyone
is happy over what we got, and disappointed over what we didn't get."

  Describing more than five hours of data collected during the
deployment phase, Tethered Satellite System Mission Scientist Dr.
Nobie Stone reported that "things in the data really pop out at you,
that are unexpected and unexplained.  We are anxious to see what these
are and what they entail."  Data showed that current levels in the
unreeling tether were higher than predicted by the models and that
electrons detected at the satellite, when current flowed in the
tether, were much more energetic than expected.

  Although obviously disappointed with the loss of the tethered
satellite, scientists got an exciting glimpse of the data they had
hoped to collect at full deployment.  The Tethered Satellite System
Science Investigator Working Group at Spacelab Mission Operations
Control is looking at options for reactivating the satellite as it
flies over the Johnson Space Center on Tuesday to gain additional
insight into Earth's charged atmosphere.  Plans are tentative at this
time.

  Dr. Carlo Bonifazi, of the Italian Space Agency, summed up mission
accomplishments by saying that "when you do research, it's not the
amount of data you collect that's important, but the information that
you can extract from the data.  If we discover two weeks from now that
we got the information we were looking for to understand the basic
behavior of the system, we could move forward." Payload Specialist
Dr. Umberto Guidoni also observed that for the first time, "we
demonstrated that tether dynamic applications work and we can generate
electricity using tethers."

  STS-75 Flight Day 6 Highlights:

 On Tuesday, February 27, 1996, 10 a.m. CST, STS-75 MCC Status Report #11
reports:

  Columbia's crew is preparing to move into the second major portion
of the STS-75 mission activating the United States Microgravity
Payload, or USMP, after completing work with several experiments
associated with the tethered satellite portion of the flight.

  The USMP experiments will gather data on various materials science
investigations including crystal growth, materials solidification and
fluid dynamics.  TSS-related experiments have been operated by the
crew throughout the night gathering data on the orbiter's payload
environment.  Investigations included measuring glow and
electrodynamic phenomena around the orbiter surfaces during thruster
firings.  At about 2:30 this afternoon, the crew will begin shifting
to USMP operations for the remainder of the flight.

  In the meantime, tethered satellite payload and ground controllers
are taking snapshots of data from the satellite sending data through
available ground stations around the world.  Commands were scheduled
to be sent directly to the satellite during several passes throughout
the day over Houston as it passed within range of the Electronics
Signal Test Lab at the Johnson Space Center.  Data collection will
continue as long as the TSS batteries remain fuctioning, about 24 - 48
hours.

  Initial configuration data received from TSS indicates that the
thruster valves, which were commanded to a closed position as the
satellite was being reeled out from Columbia, are open and that no
gaseous nitrogen remains on board.  Additionally, two of four
stabilizing gyros on the satellite give indications of being in the
"off" position.  This and all other data gathered during dumps to the
ground stations will be gathered for post-flight analysis.

  The satellite unexpectedly separated from Columbia about 7:30
p.m. CST Sunday as the tether broke within the mast.  The latest
information on the satellite shows it trailing Columbia at a distance
of 8,500 nautical miles, in an orbit 221 nm by 170 nm.  Columbia
remains in an orbit 30-40 miles lower than the satellite causing the
distance between the two spacecraft to increase by about 350 nm per
orbit.

  With the TSS operations winding down, the crew will begin
concentrating its attention on the remaining payload activity and
Commander Andy Allen will begin shifting his schedule to match that of
the Red Team of astronauts which includes Pilot Scott Horowitz,
Mission Specialist Maurizio Cheli and Payload Specialist Umberto
Guidoni.  Mission Specialist Jeff Hoffman has shifted his schedule to
match the Blue Team of mission specialists Claude Nicollier and
Franklin Chang-Diaz.

 On Tuesday, February 27, 1996, 6 a.m. CST, STS-75 Payload Status Report #09
reports: (4/15:42 MET)

  The third United States Microgravity Payload (USMP-3) has completed
its first night of full-up operations in orbit aboard the Space
Shuttle Columbia.  The Marshall-managed payload's activities are
greatly enhanced by the science teams' ability to conduct
"telescience," the process of monitoring and changing experiment
activities from ground sites to take full advantage of the time on
orbit.

  Last night, the science team for the Middeck Glovebox Facility
developed procedures for continued Glovebox operations in the event
that the facility's gas sensor warning light activates during
experiment investigations.  Earlier in the day, the gas sensors, which
monitor the Glovebox's ability to absorb experiment combustion
products, had raised some concerns when their sensor lights activated.

  The Glovebox team concluded that the sensors were activated either
by cleaning solution or packing material residues.  Because all such
materials have been flight qualified, and all combustion samples to be
burned in the Glovebox have a zero toxicity rating, the gas sensor
lights do not indicate a hazardous condition.

  For the STS-75 mission, the Glovebox, managed by Marshall's Science
and Applications Projects Office, provides an area of containment to
conduct combustion experiments.  These experiments include the
Radiative Ignition and Transition to Spread Investigation, the Forced
Flow Flamespreading Test and the Comparative Soot Diagnostics
experiment.  The first of the Glovebox's experiment runs will begin
Wednesday afternoon, 24 hours after a test of the facility's video
equipment.

  The MEPHISTO directional solidification furnace began its first
experiment run for the STS-75 mission last night.  MEPHISTO is flying
for the third time on a USMP mission in a series of cooperative
investigations between NASA, the French CNES and the French Atomic
Energy Commission.

  MEPHISTO studies the behavior of metals as they solidify.  It is
allowing scientists to closely monitor its first 32-hour- long cycle
of solidification and remelting of its three tin- bismuth alloy
samples by taking real-time temperature and resistance readings at the
point where the molten and solid metals meet called the solid-liquid
interface.  Because the molten material is not transparent,
researchers monitor electronic impulses to gain detailed information
about conditions occurring at this interface.  These data should
provide scientists with greater insights into other, more subtle
influences that impact solidification of materials.  Ultimately, the
MEPHISTO experiments may bring dramatic improvements in materials
production on Earth.

  The Isothermal Dendritic Growth Experiment (IDGE), developed by
Rensselaer Polytechnic Institute, is taking advantage of full
real-time data collection.  Now that USMP-3 is receiving the majority
of the mission's science data flow, IDGE is gathering all its
information in real-time downlink and assembling data that will test
theories concerning the effects of gravity-driven fluid flows on
solidification of molten materials. The experiment records photographs
and video images of dendrites, or Christmas tree-shaped crystals,
grown in the absence of gravity.

  Photographs are taken each time a dendrite is grown.  The
photographs, together with slow-scan television images, have produced
comprehensive microgravity data that will provide a standard for
testing solidification theories and mathematical models.  Microgravity
research such as this will lead to manufacturing improvements on Earth
in metals and alloys that display dendrite formation.

   The Space Acceleration Measurement System (SAMS), developed by the
NASA Lewis Research Center, continues to measure the microgravity
environment of the USMP-3 equipment carrier in support of the four
major onboard experiments.  Measurements are made at specific times
when microgravity disturbances are caused by events such as crew
exercise and repositioning the Shuttle's Ku-band antenna.

  A related system, the Orbital Acceleration Research Experiment
(OARE), is also managed by NASA's Lewis Research Center.  It proves
very useful on missions such as USMP-3, where it is important to
accurately depict a wide variety of disturbances in the microgravity
environment.  Working closely with SAMS, the OARE records
low-frequency activity such as the Shuttle's friction with the upper
atmosphere.  SAMS is more suitable for recording higher-frequency
activity such as crew exercise.  The OARE instrument continues to
process data in support of the USMP-3 experiments, and team members
say all is going well.

  Science activities for USMP-3 over the next twelve hours will
continue, as STS-75 enters its sixth day in orbit.

 On Tuesday, February 27, 1996, 5 p.m. CST, STS-75 MCC Status Report #12
reports:

  Columbia's crew moved into the second major objective of their
flight this afternoon, turning attention to the weightless
investigations of the United States Microgravity Payload-3.

  The crew performed further checks this afternoon of the Middeck
Glove Box Experiment, readying the equipment on Columbia's lower deck
for several studies of combustion planned later in the mission. Crew
members this evening will have a light day of activities, each
enjoying a half-day of free time as is customary on two-week long
shuttle flights.

  The crew also took a break from today's experiments for interviews
by the Cable News Network and the syndicated Conus Communications
Network.

  Earlier today, ground controllers used tracking stations scattered
around the world to receive information from the Tethered Satellite
which broke free from the shuttle on Sunday. Now in an orbit of 219 by
170 nautical miles, experiments on the satellite recorded emissions of
electrons from Columbia's cargo bay, almost half a world away,
scientists reported. Although a variety of ground tracking sites
received transmissions from the satellite, commands were sent to the
satellite only from a ground station at the Johnson Space Center in
Houston. The opportunities for ground contact with the satellite for
today are finished, but controllers plan to attempt further
communications with the satellite during orbital passes tomorrow.

  Flight controllers reported that the satellite is orbiting the Earth
in a different configuration that it was in at the time its tether
broke, with its thruster fuel depleted and no ability to receive
commands to deploy its twin science booms. But science officials said
valuable data is being received from TSS regarding the
characterization of electromagnetic fields in low Earth orbit. The
satellite, dragging about 12 miles of tether, is expected to begin to
drop out of orbit sometime in the next 30 days and will burn up in the
atmosphere during its reentry.

  Columbia, meanwhile, is functioning to near perfection, with no
mechanical problems of concern to flight controllers. The shuttle is
in a 184 by 177 statute mile orbit of Earth.

 On Tuesday, February 27, 1996, 6 p.m. CST, STS-75 Payload Status Report #10
reports: (5/3:42 MET)

  As the Tethered Satellite System (TSS) research team at Spacelab
Mission Operations Control began receiving data from the free- flying
tethered satellite, the third United States Microgravity Payload
(USMP-3) became the primary payload for the rest of mission STS-75.
This afternoon, the crew finished setting up the Middeck Glovebox for
a series of combustion experiments and prepared to conduct a series of
orbiter attitude calibrations for the Advanced Automated Directional
Solidification Furnace (AADSF), the last of four major USMP-3
investigations to be readied.

  While continuing to assemble data to support the investigation into
the cause of the tether separation, ground controllers successfully
commanded the three experiments in the upper half of the satellite to
turn on.  Now operating as a remote sensing science platform, Tethered
Satellite System (TSS) scientists are collecting real-time data about
Earth's upper atmosphere in the vicinity of the satellite.  The
Research on Orbital Plasma Electrodynamics (ROPE) equipment is
measuring ions and electrons, the Magnetic Field Experiment for TSS
Missions (TEMAG) is measuring magnetic fields, and the Research on
Electrodynamic Tether Effects (RETE) experiment is measuring electric
fields.

  With telemetry reestablished, TSS Mission Scientist Dr. Nobie Stone
reported that science teams rapidly put together plans for a set of
experiments that will make use of the free-flying satellite with the
tether still attached.  Electron beams fired from the orbiter will
create plasma disturbances that will spread through the ionosphere.
The satellite-mounted instruments will attempt to measure and
characterize these disturbances as they pass the satellite.  In
addition, the satellite's accelerometer may provide valuable
information on the condition of the tether and how well it survives
the micro-meteorite and space debris environment over the next few
days.

  Meanwhile, USMP-3 is quickly approaching full-up operations.  USMP
researchers are looking for new insights into basic physics and
materials science, while setting the stage for future long- duration
space missions.  USMP-3 scientists used the time when the TSS-1R
payload was primary to do "science of opportunity" in preparation for
the time when USMP-3 became the primary payload.

  The four experiments on USMP have all been flown previously.  The
value of experience is underscored by early progress made by the
Critical Fluid Light Scattering Experiment team.  This investigation,
called "Zeno" after the Greek philosopher who theorized about the
concept of infinity, was flown earlier on USMP-2.  Principal
Investigator Dr. Robert Gammon, of the University of Maryland, reports
that his science team has benefited from lessons learned as the Zeno
team determines the precise temperature and density needed for their
xenon sample to reach the critical point.  The critical point is the
exact pressure and temperature at which the densities of coexisting
liquid and vapor phases become identical.  The clear xenon sample will
essentially exist in both the liquid and gaseous states of matter.
This is a phenomenon that cannot be accurately measured in Earth-based
laboratories.

  Payload Commander Franklin Chang-Diaz completed setup of the Middeck
Glovebox (MGBX) with a series of checks on the video cameras.  These
cameras are an important part of the self- contained Glovebox.  The
video capability of the Glovebox records the science for later
analysis and allows investigators to view the experiments as they are
done and make needed adjustments in real time.  In the Glovebox, the
crew will conduct a series of hands-on combustion science
investigations.  The first of these, the Forced Flow Flamespreading
Test (FFFT), led by Dr. Kurt Sacksteder of the NASA Lewis Research
Center, will be run Wednesday afternoon.

  Columbia's on-board acceleration sensors have given USMP researchers
valuable information about how to make adjustments to enhance science
collection.  As the Advanced Automated Directional Solidification
Furnace goes through a "dress rehearsal" this evening, the sensors
will make measurements that will enable the science team, led by
Dr. Archie Fripp of the Langley Research Center, to work with
Columbia's flight crew who will "tweak" the orbiter's position for
maximum science return.  The team's first experiment sample will be
processed tomorrow.

  STS-75 Flight Day 7 Highlights:

 On Wednesday, February 28, 1996, 7 a.m. CST, STS-75 MCC Status Report #13
reports:

  With the focus of work aboard Columbia turning to weightless
investigations of the United States Microgravity Payload, flight
controllers in Houston and Huntsville continue to gather as much data
from the tethered satellite as possible before its batteries run out.

  USMP experiments are collecting data on various materials science
investigations including crystal growth, materials solidification and
fluid dynamics.

  Half of the crew enjoyed a half day of free time as is customary on
two-week long shuttle flights.  During the break, Pilot Scott
Horowitz, Mission Specialist Maurizio Cheli and Payload Specialist
Umberto Guidoni discussed the flight with the C-SPAN network and
answered questions from viewers.

  The ground commanding to the tethered satellite began yesterday and
is expected to continue today as it passes within range of the ground
station at the Johnson Space Center.  Payload officials will again
take snapshots of data from the satellite to determine its health
before its batteries completely discharge; this is expected within the
next couple of days.

 On Wednesday, February 28, 1996, 6 a.m. CST, STS-75 Payload Status Report #11
reports: (5/15:42 MET)

  As the third United States Microgravity Payload (USMP-3) performs
its early primary science operations aboard the STS-75 Shuttle
mission, the Tethered Satellite System (TSS) science teams at Spacelab
Mission Operations Control continue to receive data from the
free-flying tethered satellite.

  Overnight, Commander Andrew Allen maneuvered Columbia through a
series of orbiter calibrations for NASA Marshall Space Flight Center's
Advanced Automated Directional Solidification Furnace (AADSF) which
performed a "dress rehearsal" for their first experiment sample
processing, scheduled for early Thursday morning.  The Shuttle's
on-board acceleration sensors made measurements that gave the AADSF
science team valuable information about how they will make adjustments
to enhance science collection during this first experiment run.

The
AADSF will grow three cylinder-shaped crystals using samples of
lead-tin-telluride, a material used to make infrared radiation
detectors and lasers.  This process is expected to take a number of
days to complete.  It is important to conduct this kind of experiment
in microgravity in order to provide insight into the influence of
gravity-driven fluid flows on crystal formation.

  Scientists hope that information gathered from this experiment will
lead to the production of better, faster semiconductors for components
used in products ranging from automobiles to computers.  The speed and
amount of information that can be stored and sent by computers and
high-tech electronics, using sophisticated semiconductor materials,
may be increased by better control of how the semiconductors'
structures form.

  AADSF findings will help researchers develop improved processes for
semiconductor materials that cost less to produce.  "The ages of
humanity are known for the type of materials humans used, such as
'Stone Age,' 'Bronze Age,' etcetera," observed AADSF Principal
Investigator Dr. Archie Fripp of NASA's Langley Research Center.  "If
we can contribute in any way to the development of the 'Semiconductor
Age,' then we have really achieved something."

  Rensselaer Polytechnic Institute's Isothermal Dendritic Growth
Experiment (IDGE), has completed its "science of opportunity" phase
and, now that USMP-3 is the primary mission payload, has entered its
main science gathering mode.  The investigation team members are
studying the three-dimensional shape of their tiny "pine tree-shaped"
dendrite crystals.  The device consists of a thermostat containing a
growth chamber filled with a transparent substance that imitates the
behavior of metals and solidifies as it cools to form these dendrites.

  IDGE scientists, led by Dr. Martin Glicksman, used the preliminary
acceleration data gathered by NASA Lewis Research Center's Space
Acceleration Measurement System (SAMS) and Orbiter Acceleration
Research Experiment (OARE) to evaluate their opportunity science data
and to relate the size and speed of the dendrite growths with
accelerations in the microgravity environment.  Also, scientists
looked for relationships between the angle of the dendrites' direction
and the direction from which microgravity influences their growth.
The experiment's science team at Rensselaer will use their telescience
capabilities to remote-command and receive data from their IDGE
instrument.

  Early in the evening, the Critical Fluid Light Scattering
Experiment, or Zeno, science team, led by Dr. Robert Gammon of the
University of Maryland, completed the collection of dynamic light
scattering data just above their xenon sample's "critical point." The
critical point is the exact temperature and pressure at which the
sample is simultaneously in both the liquid and vapor
phase. Understanding how matter behaves at the critical point can
provide insight into a variety of physics problems, ranging from state
changes in fluids to changes in the magnetic properties of solids.
This knowledge will prove valuable in a wide variety of applications,
including liquid crystals and superconductors.

  Meanwhile, science teams for the Tethered Satellite System
demonstrated their own brand of telescience throughout the night,
commanding and receiving data from their reactivated instruments on
the satellite.  The Marshall Space Flight Center's Research on Orbital
Plasma Electrodynamics (ROPE), the Italian Space Agency's Research on
Electrodynamic Tether Effects (RETE) and the Second University of
Rome's Magnetic Field (TEMAG) experiments continue to collect what TSS
Mission Scientist Dr. Nobie Stone called "very good data" about the
satellite's interaction with its surrounding region of charged
particles and magnetic fields.

  Scientists report that they can measure a sunlight-induced
electrical charge on the satellite as it moves through the daylight
and night portions of its orbit around the Earth.  Later today, the
satellite's ROPE and RETE instruments will measure the effects of
electron gun firings from the Shuttle Electrodynamic Tether System
(SETS) on the satellite and its environment.

  Also today, science data collection by the USMP-3 experiments will
continue, and the crew will perform a Forced Flow Flamespreading Test
(FFFT), an investigation led by Dr. Kurt Sacksteder of NASA's Lewis
Research Center, the first in a series of hands-on combustion
experiments conducted in the Middeck Glovebox.

 On Wednesday, February 28, 1996, 5 p.m. CST, STS-75 MCC Status Report #14
reports:

  NASA managers decided today not to return Columbia to the Tethered
Satellite for either a close inspection or a possible retrieval after
concluding that propellant margins would not be adequate to support
the operations.

  Officials were asked to investigate the possibility of a rendezvous
with TSS.  After reviewing propellant margins, spacewalking
considerations, and radar requirements, a decision was made not to
fire Columbia's engines to begin what would have been a six-day
phased approach to meet up with the satellite.
  
  The Tethered Satellite is currently 7,100 nautical miles ahead of
Columbia with the distance between the two spacecraft closing at the
rate of 340 nm with every revolution of the Earth.  The two spacecraft
will pass within 50 nm of one another about 11:48 p.m.  Thursday, at a
Mission Elapsed Time of 7/09:30.

  Earlier today, Mission Specialist Jeff Hoffman set a record for the
most hours flown on a Space Shuttle, breaking the previous record of
975 hours 18 minutes held by Kathy Thornton. Hoffman will break the
1,000 hour mark aboard the Shuttle on Thursday.

  Work with the United States Microgravity Payload experiments continues
with the astronauts supporting a variety of investigations including
crystal growth, materials solidification and fluid dynamics.

  Columbia is functioning normally, with no problems being tracked by
the flight control team as the Shuttle orbits the Earth every 90
minutes at an altitude of 180 statute miles.

 On Wednesday, February 28, 1996, 6 p.m. CST, STS-75 Payload Status Report #12
reports: (06/3:42 MET)

  With the shift to the third United States Microgravity Payload
(USMP-3) as the primary science on STS-75, the Tethered Satellite
System (TSS) is in a "science of opportunity" mode.  The spirit of
cooperation was evident at Spacelab Mission Operations Control as the
USMP-3 team worked with their TSS colleagues to accommodate
post-tether-break science plans.

  After ground controllers successfully commanded the free-flying
satellite's on-board instruments to turn on yesterday, data began to
flow to TSS science teams in Huntsville.  TSS Mission Manager Robert
McBrayer emphasized that "a tremendous amount of cooperation" has made
this possible.  The satellite is now operating on battery power, with
enough energy to last another day, depending on how commanding and
data resources are handled.

  TSS Mission Scientist Dr. Nobie Stone confirmed that "we have a very
interesting and high-quality data set.  We are still taking data and
already are seeing evidence that some very significant things will
come out of this mission."  The science of opportunity being
formulated by the entire TSS Investigators Working Group involves
firing electron accelerators, known as "electron guns," located in
Columbia's cargo bay, to see if the satellite's instruments detect
plasma disturbances as they spread out through the ionosphere.  This
experiment has been executed once, and there are opportunities to
repeat it several times as the Shuttle and satellite move toward a
closer approach of about 56 nautical miles.

  One of the TSS primary mission objective may be met in spite of the
overall situation.  Dr. Marino Dobrowolny, the Italian Space Agency
TSS mission scientist, noted that a main goal was to characterize the
relationship between current collected and voltage across the tether.
During tether deployment, current and voltage levels were observed
under conditions that cannot be duplicated in the laboratory.  He said
"we have shed light on plasma physics questions raised in the 1920s
that have never before been understood and are too difficult to
duplicate in the laboratories or model with computers."

  Data gathered while the satellite was deployed is better than
scientists anticipated.  There are cases where twice as much current
was collected than was predicted by the best computer models
available.  This may indicate some degree of ionization around the
satellite even during the period when the satellite thrusters were not
on when no enhanced gas cloud was present.  In fact, when satellite
thruster operations were performed, the current went even higher, up
to 580 milliamps, compared to the 270 milliamps predicted by the
models.

  In addition, after commanding current to flow in the tether,
energetic electrons were observed on the satellite with energies
ranging up to 10 kiloelectronvolts -- ten times the energy of the
electron beams that were emitted.  This provides valuable clues into
the physical processes by which electrons become energized.

  The acceleration that should be seen with a 12.2 mile (19.7
kilometer) tether hanging below the satellite was predicted
theoretically to be 0.9 milli-g's, or less than one-thousandth of
Earth's gravity.  The satellite's linear accelerometer data measured
accelerations within this range, indicating the tether to be intact.
Based on this, it may be possible to tell if the tether length changes
by more than 4 kilometers due to orbital debris or micro-meteoroid
hits over the next day or so.  Dr. Stone noted that "this would be an
interesting and useful data point for future applications.  If it
doesn't sever, that's even better information."  The accelerometer
also is providing tether dynamics data that indicates a possible
swinging back and forth motion known as libration.

  During the post-break, free-flight phase, the Research on Orbital
Plasma Electrodynamics (ROPE) equipment, located on one of the
satellite's booms, is collecting information about the plasma sheath
created by applying a voltage to the boom tip.  Understanding this
effect that may be significant to geosynchronous satellites, such as
those that transmit television and telephone signals, where
differential charging occurs on the order of kilovolts.

  STS-75 Flight Day 8 Highlights:

 On Thursday, February 29, 1996, 9 a.m. CST, STS-75 MCC Status Report #15
reports:

  Columbia's crew continues its work with the United States
Microgravity Payload experiments supporting a variety of
investigations including crystal growth, materials solidification and
fluid dynamics. Meanwhile, payload controllers continue to obtain
snapshots of data from the tethered satellite as it passes within
range of available groundstations around the world.

  As TSS battery power diminishes, plans are in work to turn on
science instruments, Earth sensors and stabilizing gyros in
anticipation of the closest approach of TSS to Columbia at about 11
p.m.  central time today (approximately 07/08:50 mission elapsed
time). At that point, the orbiter should pass within about 50 miles of
the satellite possibly allowing payload bay instruments a chance to
gather data on the satellite as well.

  Because of the instability of the satellite and its varying
gravitational drag, the distance between the two spacecraft and the
time of closest approach likely will change. In any case, there is no
concern about Columbia passing too close to the satellite. Whether or
not the crew can visually observe the satellite during the fly-by will
depend on lighting conditions at that time.

  The Tethered Satellite is currently about 3,000 nautical miles ahead
of Columbia with the distance between the two spacecraft closing at
the rate of 340 nm with every revolution of the Earth.

 On Thursday, February 29, 1996, 6 a.m. CST, STS-75 Payload Status Report #13
reports: (6/15:42 MET)

  The third United States Microgravity Payload (USMP-3) completed
another night of successful operations aboard the Space Shuttle
Columbia, with the four experiments that make up the payload
processing good data in the microgravity environment of Earth's orbit.
The smooth ride aboard Columbia, in free fall around Earth, was made
even smoother yesterday as crew members restricted their movements in
"quiescent" periods.  This allowed USMP-3 researchers with the
MEPHISTO experiment to gather baseline data about the effects of
movement on their delicate semiconductor material samples by comparing
them to times of no activity.

  The scientific activities of the MEPHISTO experiment, led by
Dr. Jean-Jacques Favier of the French Atomic Energy Commission,
included a study of "g-jitter," or microgravity disturbance effects
such as those caused by crew activities and orbiter thruster firings.
As expected, the first 25-second thruster firing, or "burn," produced
accelerations of more than 10,000 micro-g's, a force equal to one-
hundredth of Earth's gravity, and provided a significant response in
the experiment's real-time data transmission.  Another 15- second
firing also produced a marked change in this signal.  The science team
observed that the measurements continued to increase for a few minutes
after each of these burns before slowly decreasing.  Before and after
each thruster firing, the crew remained in a relatively still mode to
allow scientists to perform real-time correlations of MEPHISTO's data
with information collected from the Space Acceleration Measurement
System (SAMS) aboard the Shuttle.

  The understanding gained from the MEPHISTO experiment may ultimately
lead to improvements in materials preparation and processing on Earth.
MEPHISTO uses very selective methods to study the role of
gravity-driven fluid flows in the solidification of materials.
Microgravity reduces fluid flows caused by sinking and rising,
allowing researchers to explore effects normally hidden by gravity.

  This morning, the Marshall Space Flight Center's Advanced Automated
Directional Solidification Furnace (AADSF) began its first experiment
operations, melting a lead-tin-telluride sample to test theories about
gravity's effects on growing semiconductor materials.  Today, the
instrument's science team, led by Principal Investigator Dr. Archie
Fripp, will continue melting and positioning all three samples, then
actually start growing crystals by seeding and re-solidifying the
lead-tin-telluride alloy.

  Yesterday afternoon, Pilot Scott Horowitz and Mission Specialist
Claude Nicollier performed runs of the Lewis Research Center-managed
Forced Flow Flamespreading Test (FFFT) experiment in the Middeck
Glovebox Facility.  They burned flat paper samples to help the science
team, led by Glovebox Investigator Kurt Sacksteder, study how air
motion affects flame spreading in microgravity.

  Scientists who study combustion want to know the details of how air
motion affects flame spreading and how to better control fires that
may occur on orbit.  On Earth, gravity causes hot air to rise and cool
air to fall.  Because of the complexity of the physical and chemical
processes involved, the theoretical understanding of flame spreading
in space is still a relatively new science.  The microgravity
environment available in the self-contained Glovebox aboard the Space
Shuttle is an important tool for scientists and engineers to study
this important phenomenon.

  The Isothermal Dendritic Growth Experiment (IDGE), developed by the
Rensselaer Polytechnic Institute, has completed 15 dendrite growth
cycles during its primary science phase.  Images of free-floating
dendrites, acquired during melting after a growth cycle, show no
detectable motion compared with images of dendrites attached to the
experiment's container.  Analysis of such post-melting images help
researchers define the mobility limits of the free-floating, pine
tree-shaped dendrite crystals in the microgravity environment.

  The Zeno Critical Fluid Light Scattering Experiment's sample cell
temperature continues to approach the critical temperature and
pressure at which xenon exists simultaneously in both the liquid and
vapor phases.  Zeno uses precise light-scattering measurements as an
unintrusive way of seeing changes in a xenon sample as it fluctuates
rapidly between two states of matter.

  In addition to continued sample processing by the four USMP-3
investigations, the next 12-hours will begin with the first in a
series of Comparative Soot Diagnostics combustion experiment runs in
the Middeck Glovebox.

 On Thursday, February 29, 1996, 5 p.m. CST, STS-75 MCC Status Report #16
reports:

  Columbia and the Tethered Satellite will pass within about 51
nautical miles of each other at 11:17 p.m. central time today
(approximately 7/08:59 MET), providing the astronauts a chance to
glimpse the errant spacecraft since it separated from the orbiter
Sunday night.

  Tonight's encounter with TSS marks the point of closest approach for
the two spacecraft before they begin to separate once again.
Currently, the orbiter trails TSS by a distance of about 1900 nautical
miles, with Columbia closing on the satellite at the rate of 340 nm
with each revolution of the Earth.  Whether or not the crew will be
able to see the satellite during the fly-by will depend on lighting
conditions and orbiter position.

 This afternoon, crewmembers discussed the progress of the flight
during an in-flight interview with two Philadelphia television
stations.  A second interview, at 6:08 p.m., is with the United States
Information Agency's Worldnet program.

  Columbia is functioning normally, with no problems being tracked by
the flight control team as the Shuttle orbits the Earth every 90
minutes at an altitude of 180 statute miles.

  STS-75 Flight Day 9 Highlights:

 On Friday, March 1, 1996, 6 a.m. CST, STS-75 Payload Status Report #14
reports: (7/15:42 MET)

  Researchers for the third United States Microgravity Payload (USMP-3)
are on an "incredible atomic journey," according to Principal
Investigator Dr. Robert Gammon.  He and his science team, stationed at
Spacelab Mission Operations Control, are pushing the envelope of
knowledge about the precise conditions under which one material can
coexist in two states of matter.

  This atomic journey, courtesy of the Critical Fluid Light Scattering
experiment, or "Zeno," is geared toward searching for insight into the
fundamental physics processes involved in this phenomenon.  Zeno
scientists currently are setting the stage to arrive at the point
where temperature and density combine to balance two states of matter
-- liquid and gas.  This is known as the "critical point."

  Team members are remotely commanding their small experiment cell to
cool -- slowly and methodically stepping down a range of temperatures
to reach a point where something quite remarkable happens.  The
normally clear xenon "turns milky white because it does not know
whether it really wants to be like a liquid or like a vapor.  It just
can't decide," Dr. Gammon explains.  That will be the point where the
Zeno apparatus will collect the all-important data for his
investigation.

  Yesterday, the Advanced Automated Directional Solidification Furnace
(AADSF) team members adjusted their timeline, delaying the first
crystal processing run until later today, to ensure that conditions
are right for their solidification techniques.  AADSF team members can
tell that solidification has begun in their furnace when a "seed" or
solid core forms in the molten lead-tin-telluride, a sample of
semiconductor material.  In ground-based solidification, this seed
formation would normally show up as a "spike," or sharp rise and fall,
in the temperature data the team receives from the experiment.

  When the seed formed more slowly than expected Thursday, appearing
as a "hump" instead of a spike in the data plot, due to the
low-gravity environment, the team re-melted their sample to again
verify the exact time of seed formation.  Having accomplished this,
they decided to wait for the next period of reduced crew activity,
scheduled for this evening, in order to take maximum advantage of the
relatively undisturbed microgravity environment.  Such "quiescent
periods" are necessary to allow each of three crystal samples to
develop in the best possible growth conditions.

  The Isothermal Dendritic Growth Experiment (IDGE) and MEPHISTO teams
are studying details of crystal growth to improve metals processing on
Earth.  The IDGE science team has completed data collection for their
first 20-cycle phase of primary science and have begun their second
phase.  During each cycle, the facility studies crystal structures for
clues about how to solidify liquid materials into forms with just the
right characteristics for their intended purpose.  Applications range
from aluminum to steel products.

  The MEPHISTO series of investigations explores the liquid/solid
interface, or boundary, of metal alloys.  Alloys are combinations of
metals that reinforce or add properties not found in each constituent
alone.  The goal is to develop processes to distribute constituents in
a precise manner to improve the final product. The MEPHISTO science
team has reported previously unseen results from the effects of two
scheduled Shuttle thruster firings on their molten tin and bismuth
alloy sample, which finished another round of solidification last
night.  They noticed that the thrusters had a great impact on the
sample's crystallization when fired at a perpendicular orientation, at
a 90-degree angle, to the direction in which the sample grows, but no
effect when fired parallel to that direction.  This was the first time
this effect has been demonstrated in space, and it could prove
important to materials processing in similar furnaces aboard the
International Space Station.

  Working in the Marshall-managed Middeck Glovebox, Commander Andrew
Allen successfully completed a set of Comparative Soot Diagnostics
(CSD) burns ahead of schedule due to an early start.  The CSD
experiment team, led by Dr. David L. Urban of NASA's Lewis Research
Center, received good data from the burns, which will contribute to
the understanding and prevention of possible fires on spacecraft.
Later in the night, Mission Specialist Claude Nicollier performed
Forced Flow Flamespreading Test (FFFT) runs, burning flat and
cylinder-shaped samples in the Glovebox to help FFFT investigators
learn more about how flames spread in weightlessness.

  Tethered Satellite System (TSS) "science of opportunity," during
Columbia's final approach to within 46 nautical miles of the
satellite, included firing the electron accelerators in Columbia's
cargo bay.  The electron guns' effects on the charged particles,
electrical waves and magnetic fields around the satellite were
detected by the Research on Electrodynamic Tether Effects, Research on
Orbital Plasma Electrodynamics and Magnetic Field Experiment for TSS
Mission's instruments mounted on the satellite.  All three instrument
teams reported receiving good quality data from the satellite, data
which are now being analyzed by the experiment investigators.

  Over the next 24 hours, in addition to AADSF's first sample
crystallization, the MEPHISTO crystal-growth furnace will perform
shorter and quicker melting and solidification cycles, and combustion
experiments in the Glovebox will study smoldering and ignition effects
as the second half of the STS-75 mission continues.

 On Friday, March 1, 1996, 8 a.m. CST, STS-75 MCC Status Report #17
reports:

  Columbia's astronauts had a clear view of the Tethered Satellite as
the two spacecraft passed within about 46 nautical miles
overnight. The closest approach occurred at 11:17 central time last
night (approximately 7/08:59 MET), and was captured on videotape as
the satellite and its 12-mile tether came into view.

  Meanwhile, flight controllers monitored the Tethered Satellite
through ground stations as its batteries drained, but not before
holding in for last night's fly-by.

  About 6 a.m. today, weak signals from the satellite, indicating its
battery life was waning, were observed through the Merritt Island
tracking station and the Bermuda tracking station.  During a second
pass across the southern United States about 7:30 a.m. today (7/17:12
mission elapsed time), ground controllers confirmed there was no
acquisition of signal from the satellite, effectively ending its
mission.

  Three in-flight special events are planned for the crew this morning
and early afternoon.  An Italian media interview is set for about 10
a.m.; an Italian VIP call to crewmembers Maurizio Cheli and Payload
Specialist Umberto Guidoni is set for 11:50 this morning and a Swiss
educational event with Mission Specialist Claude Nicollier is
scheduled for 2:48 this afternoon.

  Columbia is continuing to provide a stable platform for microgravity
investigations as Columbia sails 180 statute miles above the Earth,
circling the globe every 90 minutes.

 On Friday, March 1, 1996, 4 p.m. CST, STS-75 MCC Status Report #18
reports:

  Science investigations occupied much of the crew's time on board
Columbia today as the astronauts continued to support the
U.S. Microgravity Payload.

  Experiments into convection and the behavior of flame patterns in
microgravity were the focus of activity on Columbia's middeck
today. The astronauts also took time today to share their thoughts
during an Italian media interview and a Swiss educational event.

 Late in the afternoon, Commander Andy Allen, Mission Specialist
Maurizio Cheli and Payload Specialist Umberto Guidoni accepted a
congratulatory phone call from Giorgio Salvini, the Italian Minister
of Universities and Scientific Research.

  Columbia continues to perform in near flawless fashion as it sails
180 statute miles above the Earth, circling the globe every 90
minutes.

  STS-75 Flight Day 10 Highlights:

 On Saturday, March 2, 1996, 8 a.m. CST, STS-75 MCC Status Report #19
reports:

  While science investigations continued on the middeck --
specifically studying how fire spreads and soot develops in the
microgravity environment of space -- a procedure was performed to
remove ice from the core of Columbia's flash evaporator system which
shutdown earlier this morning.

  The FES core flush procedure was identical to one carried out on the
last Shuttle flight to melt ice and recover use of the subsystem which
is designed as a subtle method for dumping excess water overboard
without disrupting the experiments on board.  The FES also cools the
freon used to keep orbiter and payload electronics at operating
temperatures.

  Later today, Franklin Chang-Diaz (from Costa Rica) will be
interviewed by the Spanish NewsChannel and CNN International.  Joining
him for the 4:30 interview are Andy Allen, Jeff Hoffman and Claude
Nicollier.

  At 7:30 this evening, Jeff Hoffman with other available crew members
will receive a congratulatory call from organizers of the annual
Houston Livestock Show and Rodeo.

  Columbia's systems continue to operate well, providing a platform
for USMP operations in orbit 180 miles above the Earth.

 On Friday, March 1, 1996, 6 a.m. CST, STS-75 Payload Status Report #15
reports:  (8/15:42 MET)

  The future of high-technology electronics, metal alloys and
industrial chemical processes is the main benefactor from scientific
research in progress on the third United States Microgravity
Laboratory (USMP-3).  But the future of space-based operations also is
being shaped by the "telescience," or remote control, capabilities of
USMP-3 researchers working at Spacelab Mission Operations Control in
Huntsville.  From their unique vantage point, the USMP team is not
only gaining insight into the subtle laws of nature, they also are
directly interacting with their experiments on orbit.

  The Advanced Automated Directional Solidification Furnace (AADSF)
early today finished processing the first of three lead-tin- telluride
samples and prepared the "seed," or solid core, of their next sample's
crystal, scheduled for solidification tonight.  The AADSF team is
studying how semiconductor crystals might be improved for applications
such as infrared detectors used by the aircraft industry and in
medical technology, and for such high- tech apparatus as night vision
goggles.  Semiconductor performance is based, in large part, on
uniform distribution of elements for the best electrical properties.
Crystals such as these can be grown more uniformly in space.

  Telescience was a major tool that allowed AADSF researchers to delay
the start of their experiment when the seed, around which the sample
crystallization grows, was not indicated by the data.  The team took a
careful second look at the real-time information they received and
halted the furnace.  From this temperature data, they could determine
when the first seed formed.  Based on that information, they regulated
the temperature and position of the second sample accordingly to
ensure proper seed formation.  "We think the first solidification went
well," said Principal Investigator Dr. Archie Fripp of NASA's Langley
Research Center.  "When we get the samples back and look at them with
eyes sharper than mine, such as an electron microscope, we'll know
even more."

  The ability to remote command the unique MEPHISTO furnace has
allowed its science team members to use a new strategy to improve
their data on the stability of their sample's shape.  The approach
involves tracking small changes in the speed of their sample's growth
during several shorter and faster cycles of the furnace's processing.
During each cycle, the MEPHISTO experiment's high- temperature furnace
melts and re-solidifies a tin-bismuth mixture that acts very much like
the metal alloys used for products such as jet engine turbine blades
and electronic materials.

  MEPHISTO team members watch real-time data displays to "visualize"
the sample as it is being processed.  Based on this and additional
real-time data analysis done in Toulouse, France, and at the
University of Alabama in Huntsville, Principal Investigator Dr.
Jean-Jacques Favier carefully analyzes and modifies the furnace's
temperature and position and rate of movement over the sample to
gather the highest quality science.  "We are extremely excited to be
able to modify our sample's growth conditions in response to real-time
science data," he explained.

  Another experiment that utilizes a remote site to gather and analyze
data is the Isothermal Dendritic Growth Experiment (IDGE) team from
the Rensselaer Polytechnic Institute.  Real-time analysis by IDGE
teams working at the Marshall Center and at the Rensselaer Remote
Operations Control Center, in Troy, N.Y., has greatly reduced the time
needed to perform each growth cycle of tree-like structures, or
dendrites, like those that form when metals solidify.

  Early data gathered by the Orbiter Acceleration Research Experiment
indicate that changes in the speed of such growths are not caused by
the effects of Columbia's movement and position on small fluid flows
in the IDGE experiment chamber.  This information will become critical
in further discussions about the effects that minor disturbances, or
accelerations, have on dendrite growth.  "Time is money.  In our
limited time on orbit, typical pre-programmed experiments would have
missed out on a tremendous amount of science return if we had not been
able to adjust these growth cycles," explains IDGE Project Scientist
Ed Winsa of NASA's Lewis Research Center.

  The science team of the Critical Fluid Light Scattering Experiment,
or Zeno, also points out that remote commanding significantly reduces
on-orbit crew training time.  These highly specialized investigations
are performed by those who know them best.  "The Zeno data displays
are alive.  We monitor over 100 channels of information and maintain
close personal contact with the experiment," explains Principal
Investigator Dr. Robert Gammon, of the University of Maryland.
Informed decisions are made by those who are most knowledgeable.

  Zeno team members have been closely watching how their experiment
responds to command adjustments.  As the experiment's xenon sample
approaches ever closer to its critical temperature and density, in
which liquid and gas phases coexist, changes in Space Shuttle
Columbia's position become increasingly important.  The science team
is working in close cooperation with mission flight controllers to
control the effect of these changes on their investigation.

  Over the next 24 hours, microgravity telescience aboard the STS-75
mission will continue, as the MEPHISTO experiment remains in its new
"short cycle" mode.  The crew, meanwhile, is continuing to perform
more combustion experiments in the Middeck Glovebox, demonstrating the
importance of crew interaction in some experiments.

  STS-75 Flight Day 11 Highlights:

 On Sunday, March 3, 1996, 6 a.m. CST, STS-75 Payload Status Report #16
reports: (9/15:42 MET)

  As "telescience," or remote controlled, operations for the third
United States Microgravity Laboratory (USMP-3) continue, the crew has
been actively conducting combustion experiments.  While the four
primary USMP-3 investigations depend on remote commanding from the
ground, the three combustion investigations require, and benefit from,
intensive crew involvement.  To ensure safety, these are conducted in
the enclosed Middeck Glovebox work area.

  Combustion plays a key role in energy production, air pollution,
transportation, propulsion, global environmental heating, materials
processing and waste incineration.  Two experiments -- the Radiative
Ignition and Transition to Spread Investigation (RITSI) and the
Forced-Flow Flamespreading Test (FFFT) -- study how fires behave in
the low-gravity environment of space, so that they can be prevented
and controlled.  The third experiment -- Comparative Soot Diagnostics
(CSD) -- is designed to determine how soot produced by flames in
microgravity can be detected by on- board fire detectors.  CSD may
also help researchers better understand this major industrial
byproduct.

  Many space experiments require human interaction but contain
irritating substances or potentially hazardous conditions.  The
Marshall-managed Middeck Glovebox provides a controlled and safe work
environment for these operations.  Project Scientist Dr.  Donald
Reiss, of NASA's Marshall Space Flight Center, says that scientists
use the Glovebox to simulate experiments done in their ground-based
laboratories but that their experiment samples behave quite
differently than they do on Earth.  The facility also provides power,
light, data collection, air and particle filtration, and sensors for
gas, temperature, air pressure and humidity.  The microgravity
environment of the Space Shuttle is itself an essential tool

  RITSI principal investigator Dr. Takashi Kashiwagi, of the National
Institute for Standards and Testing, got a boost in science return
thanks to the help of Mission Specialist Maurizio Cheli.  During the
first RITSI run on Friday, Cheli was able to speed up a relatively
long process and complete half of a second run ahead of schedule.
This frees up a valuable time period for possible additional runs.
Early results from RITSI dramatically illustrate that flames produced
in space are quite different from those produced on Earth.  "They were
upside down, completely the reverse of flames one usually sees,"
Dr. Kashiwagi explained.  On Earth, warm air rises, and cool air falls
due to buoyancy-driven convection.  In microgravity, the convective
process is virtually eliminated.

  The Forced Flow Flamespreading Test (FFFT) studies how air motion
affects flame spreading to be able to better prevent or control fires.
When a fire starts on Earth, flames spread due to the movement of air
around and through the flames.  Air motion also supplies oxygen to the
fire, removes combustion products and controls how heat is released
and the flame is distributed.  Dr.  Kurt Sacksteder and his
investigator team from NASA's Lewis Research Center watched closely as
flat paper and cellulose cylinder fuel samples were heated and
ignited.  The FFFT low-speed wind tunnel creates air movements of one
to four inches per second, much slower than can be properly studied on
Earth, where normal gravity causes air flows of at least ten inches
per second.

  As Pilot Scott Horowitz conducted an FFFT run, he adjusted the
Glovebox's camera angle and focus to give the science team a better
view of what he termed a "blue ball moving down the tube," referring
to the cylindrical ashless paper sample he had lit up.  Horowitz also
reported seeing a "yellow flame inside the blue flame that is quite
spectacular.  I've never seen anything like this."  Dr. Sacksteder
said that the information his science team already has gathered will
take months to fully analyze.

 Dr. David Urban, also of the Lewis Center, is principal investigator
for the Comparative Soot Diagnostics experiment.  He worked through
the Crew Interface Coordinator at Marshall who, in turn, sent up voice
commands to Commander Andrew Allen to "tweak" various parameters such
as fan speed and the ignition setting.  Dr. Urban explained that
"microgravity is quite different from the laboratory on Earth where we
use models to guess the power it will take to ignite a material.  In
orbit, we realized that we could reduce the ignition power settings."

  Over the next 24 hours, dedicated microgravity operations will
continue with both MEPHISTO experiment teams, at the French Space
Agency in Toulouse, France, and at the University of Alabama in
Huntsville, Alabama, processing real-time data from their furnace's
tin and bismuth alloy sample.  The sample is again undergoing longer,
slower melting and re-solidification cycles to take advantage of the
best possible crystal growth conditions.  Later today, the Advanced
Automated Directional Solidification Furnace (AADSF) team will
solidify their third lead-tin-telluride crystal.  Meanwhile, the
Critical Fluid Light Scattering Experiment continues cooling its xenon
sample ever closer to its critical temperature.  Also, tomorrow
morning, the Isothermal Dendritic Growth Experiment (IDGE) team will
shift its main remote control and data collection activities to the
Rensselaer Polytechnic Institute, the first time that a campus site
has ever sent remote commands to the Space Shuttle.

 On Sunday, March 3, 1996, 8 a.m. CST, STS-75 MCC Status Report #20
reports:

  Flying 180 miles above the Earth, Columbia continues to provide a
stable platform for the experiments comprising the United States
Microgravity Payload mission with all orbiter systems performing well.

  Science investigations continued through the night without
interruption. Among the activities, crew members worked with an
experiment called the Forced Flow Flamespreading Test which studies
how flames react in the absence of gravity.

  This morning, Commander Andy Allen had some time to relax while Pilot
Scott Horowitz, Mission Specialist Maurizio Cheli, and Payload
Specialist Umberto Guidoni talked with Voice of America about the
progress of the flight so far. Later in the day, Horowitz, Cheli and
Guidoni will have a break from their payload activities while Allen
continues the scientific investigations.

  The Blue Team will wake for its next shift at shortly after 3
p.m. Central.  Columbia continues to orbit the Earth in smooth fashion
at an altitude of 180 miles, completing one revolution of the Earth
every 90 minutes.

  STS-75 Flight Day 12 Highlights:

 On Monday, March 4, 1996, 8 a.m. CST, STS-75 MCC Status Report #21
reports:

  Science investigations continue aboard Columbia as mission managers
on the ground contemplate extending the flight at the request of the
United States Microgravity Payload customer.

  Meanwhile, studies into how flame behaves in the absence of gravity
continue in a controlled environment on the middeck of the orbiter.
The investigations will hopefully provide additional data for improved
fire-fighting techniques on Earth.

  From an orbiter standpoint, Columbia is in excellent shape supporting
the USMP operations.  One of the three navigation units on board --
Inertial Measurement Unit number 3 -- was turned off yesterday after
controllers monitored small drifts in its gyroscopes.  Drifts such as
these are compensated through alignments periodically and pose no
problem for the flight duration since only one IMU is required for on
orbit operations.  The unit will be turned back on before landing day.

  Columbia is in an orbit 182 by 171 statute miles above the Earth
circling the globe every 90 minutes.

 On Monday, March 4, 1996, 6 a.m. CST, STS-75 Payload Status Report #17
reports: (10/15:42 MET)

  The four microgravity experiments that make up the third United
States Microgravity Payload (USMP-3) complement depend on the
smoothest, quietest ride available on the Space Shuttle.  As Columbia
orbits in free-fall, it, along with everything on board, experiences
the same gravitational pull; but with no resistance to the
gravitational force, people and objects fall at the same speed and
float within the Shuttle.  Each USMP-3 investigation was precisely
planned to take advantage of this valuable research tool.  They also
depend on the Shuttle itself, its on-board acceleration monitors, and
the crew's cooperation as integral elements of their research methods.

  Scientists using the NASA Marshall Space Flight Center's Advanced
Automated Directional Solidification Furnace (AADSF) have finished
growing their third and final sample of semiconductor material.  The
furnace is now in a 15-hour cooling mode in preparation for stowage.
The AADSF uses a high-temperature chamber in which three samples of
the material lead-tin-telluride have been processed.  During the
mission, the crew changed the Shuttle's orientation and reduced their
activities throughout quiet, or "quiescent," periods.  The result was
a smooth, excellent microgravity environment in which each sample
could crystallize, testing the results with different alignments of
growth direction, relative to the direction of flight.

  AADSF grew its first sample vertically, pointing away from Earth,
with the hot end at the top and the cool end at the bottom, while the
second crystal solidified in the opposite direction, with the cool end
up and the hot end down.  The third sample represented what would be a
horizontal crystal growth on Earth.  Growing the crystals in different
directions will give the AADSF scientists insight on how important
such orientations will be for sample processing aboard the
International Space Station.

  "As the Space Station structure grows, the orientation of its
microgravity environment could change, and affect the direction of
samples growing in an on-board furnace," explained AADSF Principal
Investigator Dr. Archie Fripp.  "If there's a measurable difference
between the uniformity of semiconductor samples grown in different
directions on this mission, then we know that this will be significant
on the Space Station."  The uniformity of the AADSF samples being
returned for analysis will be compared with that of Earth-grown
crystals to shed light on how to improve ground-based processing of
such materials.

  The Shuttle's attitude is also crucial for the MEPHISTO experiment,
one in a series of cooperative investigations between NASA, the French
Space Agency and the French Atomic Energy Commission.  MEPHISTO uses a
similar furnace to melt and resolidify a tin-bismuth alloy, or mixture
of metals.  Last night and throughout the mission, the experiment team
used data gathered during firings of the Shuttle's reaction control
thrusters to record the effects of orbiter accelerations on the
samples.  According to MEPHISTO Principal Investigator
Dr. Jean-Jacques Favier, science teams at the French Space Agency's
center in Toulouse and at the University of Alabama in Huntsville are
getting good results by correlating this real-time data with
information from Columbia's on-board Space Acceleration Measurement
System.

  Scientists working with the NASA Lewis Research Center's Critical
Fluid Light Scattering Experiment, or Zeno, have further refined their
estimate of their xenon sample's "critical point" by adjusting the
experiment's heat sensors.  As Zeno approaches closer and closer to
this critical temperature and density, in which gas and liquid phases
coexist, changes in Columbia's position become increasingly
important. The Zeno science team, led by Dr. Robert Gammon of the
University of Maryland, is working with mission flight controllers to
control the effects these changes have on their investigation.

  Early in the mission, before their primary science activities began,
investigators for the Rensselaer Polytechnic Institute's Isothermal
Dendritic Growth Experiment (IDGE), led by Dr. Martin Glicksman,
studied the effects that a variety of orbiter attitudes had on their
experiment.  Using data gathered by the on-board Orbiter Acceleration
Research Experiment, they compared the influence of the Shuttle's
microgravity directions with the direction that their microscopic pine
tree-shaped dendrite crystals grew.  The IDGE team discovered that
small fluid flows caused by Columbia's gradual, slow movement had no
effect on the dendrites' growth rate.  The shape and speed of dendrite
growth ultimately determines the strength and durability of a range of
metals from aluminum to steel.

  The IDGE team has already completed over 90 of its planned 120
dendrite growths.  This kind of space science unmasks processes that
are obscured on Earth, where gravity-induced flows and other phenomena
cloud the waters of understanding.  Just as a jet of hot water changes
the shape of an icicle, fluid flows caused by gravity on Earth distort
the shape of dendrite tips.  Therefore, precise determination of
dendrite shapes can best be performed in the microgravity environment
of space.

  In the next 24 hours, more combustion studies for the Forced Flow
Flamespreading Test and Radiative Ignition and Transition to Spread
Investigation will continue in the Glovebox.  Meanwhile, Commander
Andrew Allen and Pilot Scott Horowitz will maneuver Columbia through a
360-degree roll in order to stir the MEPHISTO furnace's sample, and
the IDGE team at Rensselaer Polytechnic Institute will issue the first
ever remote command from a campus site to actually control an
experiment aboard the Space Shuttle.

 On Monday, March 4, 1996, 5 p.m. CST, STS-75 MCC Status Report #22
reports:

  Columbia's astronauts will spend an additional day in orbit after
flight controllers opted to extend the flight to support ongoing
scientific investigations with the United States Microgravity Payload.

  Commander Andy Allen responded to the news by telling flight
controllers the crew was ready to support any additional mission
extensions. With the additional day, landing is now set for 6:13
a.m. CST on March 8.

  Columbia's astronauts also may have an opportunity to view the
Tethered Satellite once again as the two spacecraft will pass within
40-50 nautical miles of each other mid- morning Tuesday.  Flight
controllers will work through the night to refine the exact time of
tomorrow's close approach. Currently, Columbia trails the satellite
at a distance of 3,900 nautical miles, closing the gap at the rate of
314 nautical miles with every orbit of the Earth.

  The seven-member crew will discuss the progress of the mission with
reporters in the United States and Europe during the traditional
in-flight news conference at 5:54 central time Tuesday morning.

  STS-75 Flight Day 13 Highlights:

 On Tuesday, March 5, 1996, 8 a.m. CST, STS-75 MCC Status Report #23
reports:

  Aboard Columbia, crew members continue to work around the clock
investigating flame behavior in a controlled, microgravity
environment.  Early today, a balky cooling system froze up again but
was cleared using the same procedure run a couple of days ago.

  The flash evaporator system core flush procedure was identical to the
one carried out on Saturday to melt ice and recover use of the
subsystem which is designed as a subtle method for dumping excess
water overboard without disrupting the experiments on board.  The FE
also cools the freon used to keep orbiter and payload electronics at
operating temperatures.

  The unit was turned on to evaluate its operation with freon running at
a slightly higher temperature than usual to prevent ice formation in
the core.  The test was conducted on one of two controllers for the
unit.  A second test on the alternate controller may be conducted
later.

  Columbia is scheduled to pass within 50 to 60 miles of the tethered
satellite at 10:25 this morning, just as the satellite enters orbital
sunrise.  It is unclear whether the crew will be able to view the
satellite as it did several days ago.

  This morning, the astronauts took time out from science operations to
discuss the progress of the mission with reporters in the United
States and Europe.

  With an extra day on orbit for science operations, the seven
astronauts will continue work supporting the United States
Microgravity Payload experiments.  The end of Columbia's 19th
mission is now scheduled for 6:19 a.m. central on Friday.

  Despite the intermittent freeze-up of the FES, the orbiter continues
to provide a stable environment for USMP operations.  Columbia is in
an orbit 181 by 173 statute miles.

 On Tuesday, March 5, 1996, 6 a.m. CST, STS-75 Payload Status Report #18
reports: (11/15:42 MET)

  Along with yesterday's decision to extend the third United States
Microgravity Laboratory (USMP-3) mission by one day to enhance science
return, the space science network also expanded with an historic first
for microgravity science.  "This is the first time a principal
investigator has commanded a microgravity science instrument on the
Space Shuttle from his home institution -- a U.S. college campus,"
USMP-3 Program Scientist Dr. Steve Davison reported, referring to the
remote commanding of the Isothermal Dendritic Growth Experiment
(IDGE).

  Dr. Martin Glicksman, of the Rensselaer Polytechnic Institute (RPI)
in Troy, N.Y., has the distinction of being that principal
investigator.  Around 9:10 a.m. CST, one of Dr. Glicksman's team
members, who joined him from the NASA Lewis Research Center, sent a
command to their experiment in Columbia's cargo bay.  That step began
a third science phase for the dendrites research team, to continue
studying how metal alloys solidify free from the convective flows
caused by Earth's gravity.

  Throughout the mission, the Rensselaer Operations Control Center
crew has been working hand-in-hand with their counterparts at the NASA
Marshall Space Flight Center's Spacelab Mission Operations Control to
analyze data produced by the IDGE experiment.  Now, with RPI in the
driver's seat, the results of their first growth cycle became clear,
as the first dendrite of this operational phase emerged in record
time.  The characteristics of these microscopic crystals help
determine the strength and flexibility of products such as automobile
engine blocks and jet engine turbine blades. The ultimate goal of the
IDGE investigation is to improve ground-based materials processing for
metals ranging from aluminum to steel.

  Another collaborative effort between NASA centers is the Advanced
Automated Directional Solidification Furnace (AADSF) investigation.
AADSF brings together a sophisticated Marshall- developed furnace for
growing semiconductor materials and a science team under the direction
of Principal Investigator Dr.  Archie Fripp of NASA's Langley Research
Center.

  The three delicate lead-tin-telluride crystals that have been
successfully grown by AADSF during this mission are slated for
microscopic study when the samples are returned to Earth.  Referring
to the detailed science support provided by the Spacelab Mission
Operations Control cadre, Dr. Fripp commented that his experiment
performed "flawlessly."  "The pilot and crew put the Shuttle in the
proper attitudes required for sample processing and held them there,"
Fripp said.  Monday afternoon, the high- temperature AADSF furnace was
cooled and prepared for landing on Friday.

  The Critical Fluid Light Scattering Experiment, known as Zeno, also
shows the value of cooperation between NASA, academia and industry.
Under the direction of Dr. Robert Gammon of the University of Maryland
in College Park, the Zeno team includes members of NASA's Lewis
Research Center and Ball Aerospace.  As his research team moves to
within millionths of a degree of the point where the xenon sample will
exist simultaneously as a liquid and a gas, known as the critical
point, Dr. Gammon also complimented the work of the Spacelab Mission
Operations Control cadre.  This special operations team works with the
orbiter crew to put the Shuttle in the best possible position for the
USMP-3 microgravity experiments.  The basic science questions that the
Zeno investigation seeks to answer could improve chemical engineering
processes ranging from applying special paints to handling toxic
waste.

  The MEPHISTO investigation brings together nations working toward a
common goal, with their French Space Agency center in Toulouse,
France, and their NASA teams at the Marshall Center and the University
of Alabama in Huntsville all gathering data about crystal
solidification.  "Most of the materials we use are formed by
solidification," explained MEPHISTO principal investigator Dr.
Jean-Jacques Favier.  "This is true for semiconductors as well as
high-strength alloys."  The Information Age has linked people from
around the world, and research conducted by the international MEPHISTO
team could lead to faster computers and more versatile metals.

  In the next 24 hours, combustion experiments in the Middeck Glovebox
will continue gathering more science than originally planned, as crew
members burn additional samples for the Radiative Ignition and
Transition to Spread Investigation.  The Marshall- managed Glovebox
experiments are contributed by NASA's Lewis Research Center and the
National Institute for Standards and Testing.  Meanwhile, the MEPHISTO
team plans to speed up one of their furnace's solidification cycles to
coincide with a Shuttle thruster firing to monitor its effect on their
sample.

 On Tuesday, March 5, 1996, 4 p.m. CST, STS-75 MCC Status Report #24
reports:

  Columbia's astronauts had one last look at the Tethered Satellite
late this morning telling flight controllers they could see both the
satellite and the tether hanging beneath it.

  Lighting precluded a viewing opportunity during the point of closest
approach between the two spacecraft, but one orbit later the crew saw
and filmed TSS from a distance of about 450 nautical miles.  The
videotape was played back for flight controllers on the ground this
afternoon.  Today's pass of the satellite marks the final viewing
opportunity for the seven astronauts on board Columbia.

  Shortly before 7 p.m. central today, Franklin Chang-Diaz, Jeff
Hoffman and Claude Nicollier will participate in the final on-orbit
interview for the flight.  The three crew members will discuss their
missions with both Univision and Telenoticias, the two largest
Hispanic television networks.

  Wednesday morning, Commander Andy Allen will attempt to make contact
with the crew of Atlantis on Launch Pad 39-B. STS-76 Commander Kevin
Chilton and the crew of the next Shuttle/Mir mission will be on board
Atlantis participating in a final dress rehearsal of their planned
March 21 launch.

  Columbia continues to provide a stable platform for the continuing
scientific investigations being conducted in the United States
Microgravity Payload.

  STS-75 Flight Day 14 Highlights:

 On Wednesday, March 6, 1996, 8 a.m. CST, STS-75 MCC Status Report #25
reports:

  Columbia flew over the Shuttle launch site this morning allowing
STS-75 Commander Andy Allen and STS-76 Commander Kevin Chilton the
opportunity to talk briefly while the Atlantis crew practiced its
launch countdown at the Kennedy Space Center.

  STS-76 remains scheduled for launch in the early hours of March 21
to begin the third docking mission of a Shuttle to the Russian Space
Station Mir.  The mission commanders exchanged greetings as the STS-75
crew crowded around Columbia's overhead windows to catch a glimpse of
KSC as they passed overhead.

  Meanwhile, with an extension day ahead of them, Columbia's seven
astronauts continue around the clock operation and oversight of the
various microgravity investigations that make up this third mission of
the United States Microgravity Payload.

  Small thruster firings to put Columbia into a subtle 360-degree
rotation were conducted to allow experimenters the opportunity to
gather data into how movements such as these affect samples being
grown in the quiet, stable environment of space.

  Mission managers are evaluating the long-range weather forecast for
Friday -- the scheduled day for landing -- to determine if it will be
acceptable for landing.  The current landing time is 6:19 a.m. central
on the first of three available opportunities that day.  Columbia has
enough consumables on board to stay in space into the early part of
next week.

  Columbia continues to provide a stable platform for the continuing
scientific investigations being conducted in the United States
Microgravity Payload.

 On Wednesday, March 6, 1996, 6 a.m. CST, STS-75 Payload Status Report #19
reports: (12/15:42 MET)

  "The agreement to extend the STS-75 mission length by one day
demonstrates NASA's commitment to the type of science that will be
typical of Space Station operations."  That was the assessment of
Sherwood Anderson, Mission Manager for the third United States
Microgravity Payload (USMP-3), as he emphasized the value of each day
in orbit for microgravity science experiments aboard Columbia.

  An extra day for the unique Space Shuttle laboratory will give the
MEPHISTO science team an unexpected opportunity to test critical
theories about materials solidification in a way that cannot be done
on Earth.  Last night, they adjusted the speed of one of their
solidification cycles to observe the effects of a Shuttle thruster
firing on a tin-bismuth mixture.  They also studied the influence of
two thruster firings in opposite directions.  These orbiter maneuvers
simulate those that will occur on the International Space Station.

  The MEPHISTO scientists are studying the stability of the point
where the front of their solidifying crystal changes from the shape
commonly formed during semiconductor crystal growth, to the shape that
appears when metals solidify on Earth.  Principal Investigator
Dr. Jean-Jacques Favier of the French Atomic Energy Commission, says
the data quality he anticipates obtaining will be better than any to
date.  "We expect results within five-percent accuracy on some of the
crystal structures with the extra runs," Dr. Favier explained.  He
noted that, based on the success of Shuttle flights, "MEPHISTO is an
ideal apparatus for long-term operations on the Space Station."

  The Critical Fluid Light Scattering Experiment, known as Zeno, is on
the verge of taking a xenon sample to the precise conditions -- a
combination of temperature and density -- where it reaches its
"critical point."  This is where the sample will exist in both the gas
and liquid states simultaneously.  More time makes "the difference
between seeing the peak of 'Mt. Zeno' and setting foot on the summit,"
explained USMP-3 Mission Scientist Dr. Peter Curreri.

  Since the Zeno team is journeying an uncharted path, they do not
know just exactly where the top of the mountain is, but all indicators
show that the small steps they are taking are putting them closer and
closer to their elusive goal.  This stage of the experiment is also
"like reading a great mystery novel and getting near the end, but
knowing all the while that you are running out of time to finish the
last chapter," says Principal Investigator Dr. Robert Gammon of the
University of Maryland.  This basic science experiment will provide
valuable knowledge for a variety of fields, including liquid crystals
and superconductors.

  Benefiting from hands-on crew member work, Middeck Glovebox
combustion experimenters completed all their burn samples Tuesday,
both primary and spares.  And the additional time on orbit was an
unexpected bonus for Glovebox engineers.  They sent up detailed
directions for the crew to perform checkout and evaluation before
stowing this special enclosed work compartment.  According to Glovebox
Facility Manager David Jex, of the Marshall Center, "these procedures
will give the Marshall project team a post- operation look at Glovebox
performance following a range of combustion experiments completed over
the last few days."  Dr.  Curreri points out that "the mix of remote
controlled experiments in Columbia's cargo bay, with the hands-on
Glovebox demonstrations in the Shuttle middeck, have proven the
compatibility of the two approaches to conducting science on orbit."

  According to Principal Investigator Dr. Martin Glicksman, the
Rensselaer Polytechnic Institute's Isothermal Dendritic Growth
Experiment (IDGE) is now getting 10 percent more data from each
additional day of operations.  The more data gathered, the better
their statistical sampling will be.  This basic research will help
scientists better understand materials, materials processing and the
potential the microgravity environment offers for research.
Ultimately, it may lead to improvements in production methods and
materials on Earth.

  While waiting for the day that microgravity research will be
conducted over a period of months aboard the International Space
Station, USMP-3 scientists are taking full advantage of this one- day
mission extension.  Each extra day in space nets a significant return
on investment.  "The contingency day gives us the flexibility to come
home with more than 100 percent of planned science," according to
Dr. Curreri.

  Over the next 24 hours, the Zeno experiment will continue to
approach xenon's critical point, and the MEPHISTO team will ask the
flight crew to maneuver Columbia through a 360-degree roll to stir the
furnace's samples and gain additional science data.  Meanwhile, the
IDGE team continues remote commanding operations from the Rensselaer
Operations Control Center in Troy, N.Y.

 On Wednesday, March 6, 1996, 4 p.m. CST, STS-75 MCC Status Report #26
reports:

  After 13 days in orbit, Columbia's astronauts are preparing for
their return trip to Earth.

  Tonight, the crew will deactivate and stow the Middeck Glove Box
experiment, used during the flight to study the behavior of flame in a
microgravity environment. A special low-light camera in Columbia's
payload bay, called TOP, will make some final observations of the
luminous glow that surrounds the shuttle as its surfaces react to
atomic oxygen.

  Early Thursday morning, Commander Andy Allen, Pilot Scott Horowitz
and Mission Specialist Maurizio Cheli will perform the standard checks
of Columbia's flight control surfaces and reaction control system to
prepare the orbiter for reentry and landing.  Allen and Horowitz also
will fine tune their landing skills using a portable laptop computer
called PILOT which simulates the orbiter's reentry and landing
profile.

  There are three opportunities for Columbia's return to the Kennedy
Space Center on Friday morning.  The targeted landing time is 6:19
a.m. central, with back-up opportunities at 7:55 a.m. and 9:31 a.m.
Mission managers are evaluating the long-range weather forecast for
Friday to determine if it will be acceptable for landing at KSC.
Current predictions call for low, broken and scattered clouds, and a
chance of rain and gusty winds. The alternate landing site at Edwards
Air Force Base in California, will not be called up to support a
Friday landing, but weather conditions at Edwards are expected to be
acceptable throughout the weekend.

Columbia continues to perform well as its 19th journey in space nears
its end.

  STS-75 Flight Day 15 Highlights:

 On Thursday, March 7, 1996, 6 a.m. CST, STS-75 Payload Status Report #20
reports: (13/15:42 MET)

  As the STS-75 mission nears the finish line, the prize for the third
United States Microgravity Payload (USMP-3) research teams is data as
diverse as their experiments.  "USMP-3 has given scientists a richness
of information about the space environment, plus real-time interaction
that now extends from a university environment into space," said
USMP-3 Mission Scientist Dr. Peter Curreri.  Referring both to overall
mission success and the first remote commanding of a Space Shuttle
microgravity science instrument from a U.S. college campus, he added,
"these accomplishments give us the sense that orbital space is ours to
manipulate to further our knowledge."

  The Critical Fluid Light Scattering Experiment, known as Zeno, is
providing data about today's final approach to the xenon sample's
critical point.  A fluid's critical point is the precise temperature
and pressure at which it exists as both a liquid and a gas.  At
"supercritical temperatures," fluids make remarkable solvents and have
other applications, such as the use of carbon dioxide at its critical
point to extract caffeine from coffee beans.  Near the critical point,
the normally clear xenon sample undergoes some dramatic physical
changes, going from clear to cloudy as the fluid fluctuates between
vapor and liquid states.

  To determine the precise point where this phenomenon occurs, the
Zeno team relies on over 100 channels of data from their experiment,
updated every second, to plot statistical curves that point to the
sample's critical temperature.  These plots, known as correlograms,
show the relationship between temperature and pressure to give
researchers clues as to exactly when the critical point is reached.

  "When you get way up near the top of Mount Zeno, everything has to
move very slowly, like climbing through the low-oxygen environment of
a mountain at high altitudes," explained Principal Investigator
Dr. Robert Gammon of the University of Maryland, referring to his
desired slow approach to the critical point.  As the sample's
temperature is nudged downward through ever-smaller steps, the Zeno
light-scattering equipment measures the xenon's cloudiness, caused by
variations in density near the critical point.  In addition to these
real-time measurements, the Zeno team will further analyze the set of
correlograms, along with light- scattering measurements, to gain
insight into this unusual state of matter.

  Early this morning, the joint U.S./French MEPHISTO experiment began
solidifying its final crystal samples to be brought back to Earth for
post-flight analysis.  Using a high-temperature furnace and three
samples of a tin-bismuth alloy, representative of mixtures used for
semiconductors and metal alloys on Earth, MEPHISTO studies the point
at which materials change from the melted to solid state.  This is
done by selectively heating and cooling the material, while making
noninvasive electronic measurements -- readings that do not interfere
with the actual crystallization process.

  With help from the Space Acceleration Measurement System, the
MEPHISTO team again adjusted their sample's growth rate in response to
Shuttle maneuvers.  This knowledge could lead to the development of
furnaces that compensate for unavoidable acceleration effects in
future space experiments.  Today, the team will "flash-cool" a portion
of one of their final samples to preserve the crystal's shape for
microscopic analysis.

  Yesterday, crew members prepared the Middeck Glovebox, a versatile
facility for hands-on lab work in space, for landing.  They also ran
procedures to gather engineering data comparing checkout steps
performed in low gravity with similar procedures conducted on the
ground.  This gives better assurance that such procedures will work
when this facility flies later this year on the Russian space station
Mir and in the future on the International Space Station.

  Using the Glovebox over the course of the mission, crew members
burned 65 samples, ranging from paper to Teflon, while researchers
closely observed how these samples reacted in low gravity, free from
the effects of rising hot air and falling cool air found on Earth.
The combustion researchers gathered more than 125 percent of planned
scientific data, in the form of video and photographs, in order to
better understand how to control and prevent fires.  Other data from
the Glovebox include soot and ashes, as well as particles trapped in
the facility's filters.

  Having completed primary science collection for the Rensselaer
Polytechnic Institute's (RPI) Isothermal Dendritic Growth Experiment
(IDGE), scientists at RPI in Troy, N.Y., and at Spacelab Mission
Operations Control in Huntsville, continue analyzing the dozens of
video images they have been collecting from on board Columbia.  The
images will reveal, in greater detail than ever before possible, how
microscopic dendrites grow free from the sedimentation and convection
effects experienced on Earth.  As most molten materials solidify, they
form tiny crystals, or dendrites, that look like frost on a cold
window.  The size, shape and direction of these crystals dictate the
final properties of the resulting solid materials.

  "Now, we're using our 'telescience' capabilities to probe the effect
of our sample container on solidification," explains IDGE Research
Scientist Dr. Matthew Koss.  "This is important because, eventually,
every metal product is affected by the container it's in."  After
landing, the IDGE team will use a series of photographs, taken from
two 90-degree angles, to compose three-dimensional images of these
dendrites.

  Over the next 18 hours, the MEPHISTO, Zeno and IDGE experiments will
be deactivated in preparation for Columbia's landing.

 On Thursday, March 7, 1996, 4 p.m. CST, STS-75 MCC Status Report #28
reports:

  Columbia's astronauts have readied their ship to return to Earth
after a journey of more than 6 million miles.  Landing at the Kennedy
Space Center is targeted for 7:52 a.m.  central time, the first of two
opportunities to KSC tomorrow.

  Early this morning, during the standard pre-landing check of
Columbia's flight control system, one of four data channels
failed. The command path involved is one of four that commands an
actuator to move flight control surfaces during reentry.  The command
path is considered "failed", but the three remaining command paths
remain healthy and in position to support tomorrow's planned landing.

  Throughout the night, the reentry flight control team will continue
to review weather conditions at the primary landing site at KSC, as
well as the alternate landing site at Edwards Air Force Base in
California.

  Flight controllers opted to forego an earlier KSC landing
opportunity at 6:16 a.m. central time, because of forecast low clouds
and the possibility of rain and gusty winds.  Weather conditions are
expected to improve later in the morning to support the two KSC
landing opportunities.

  The first landing opportunity would see a deorbit firing of
Columbia's engines at 6:49 a.m.  central time, with a landing on
Runway 33 at 7:52 a.m.  The second opportunity, one orbit later, has a
deorbit burn at 8:25 a.m., followed by landing at 9:27 a.m.

  If weather precludes a landing at KSC, there are two opportunities
for a Friday landing at Edwards Air Force Base.  The first would see a
deorbit burn of Columbia's engines at 8:15 a.m. central time, with
landing on Runway 22 at 9:27 a.m.  The second opportunity, has a
deorbit burn at 9:54 a.m. central time with landing at 10:54 a.m.
Weather in California is predicted to be acceptable to support
landing.

  If Columbia remains in orbit an additional day due to weather
conditions, there are three landing opportunities available on
Saturday at KSC and three at Edwards.

  STS-75 Flight Day 16 Highlights:

 On Friday, March 8, 1996, 9 a.m. CST, STS-75 MCC Status Report #29
reports: 

  Shuttle managers today elected to wait for better weather in Florida
on Saturday due to unpredictable cloud cover this morning at Kennedy
Space Center.  The weather forecast indicates improved conditions
Saturday.

  Today's landing opportunities slipped by one by one as the flight
control team saw some improvement in cloud cover at the KSC landing
site, only to be faced with a prediction of bands of low clouds moving
over the runway area at the scheduled landing time.  Weather was
generally good at Edwards Air Force Base, the alternate site, but with
some hope of better weather in Florida Saturday, managers decided to
keep Columbia in orbit one additional day.

  Early Friday, Columbia's astronauts prepared the vehicle for entry,
packing up gear aboard the shuttle and closing the payload bay doors.
They will now reopen the doors to provide necessary cooling and go
through the deorbit preparations again Saturday morning.

  The first opportunity Saturday for a KSC landing comes on orbit 250
with a deorbit burn at 5:23 a.m. CST and a landing at 6:24 a.m. CST.
The second KSC opportunity is at 7:59 a.m. CST and the final
opportunity in Florida comes at 9:35 a.m.  Edwards landing
opportunities Saturday morning are at 7:51, 9:26 and 11:01 CST.

 On Friday, March 8, 1996, 9 a.m. CST, STS-75 Payload Status Report #21
reports: (14/18:42 MET)

  With over 14 days of research in space accomplished, the STS-75
Space Shuttle mission of Columbia has produced a vast array of
scientific information for diverse applications -- from using
electrically conducting tethers in space to improving ground-based
materials processing.

  The combination of real-time data already collected and samples on
their way back into the hands of experimenters will stoke the fires of
scientific investigation throughout the weeks and months ahead.
Researchers for both the Tethered Satellite System Reflight (TSS-1R)
and the third United States Microgravity Payload (USMP-3) mission
phases are already hard at work to learn what these data mean.

  "The Italian tethered satellite was built about 100 miles from the
birthplace of Christopher Columbus.  Today, he is remembered not for
what he set out to find, but what he actually discovered."  That is
how NASA Mission Scientist Dr. Nobie Stone characterized the
importance of the tethered satellite experiment.  The mission
demonstrated that electrical current-collection and power-generating
capabilities of the system can be several times the predicted levels.
This knowledge will help researchers assess and shape the future of
tethered satellites in space, said Stone and Dr. Carlo Bonifazi,
principal investigator from the Italian Space Agency.  Promising
fields for applications range from spacecraft power production to
placing scientific platforms in unexplored regions of Earth's
atmosphere and changing a spacecraft's orbit.

  Despite the unexpected break in the tether on which the satellite
was being unreeled from Columbia, TSS scientists collected data that
has helped them meet several key science goals, according to Stone and
Bonifazi.  Early results, in fact, go beyond existing models of plasma
and space physics phenomena.  Stone predicted that contemporary texts
that treat these subjects will address the surprising findings already
gained from the deployment phase.  The TSS mission also included
several "firsts."

  A primary goal was to study the relationship between voltage and
current in a tethered satellite system.  Currents measured during the
deployment phase were at least three times greater than predicted by
analytical modeling.  When planning to use tether-produced energy as a
power system, or as an electrical generator in space, the amount of
power that can be generated is directly proportional to the current.
This means that it may be possible for a tether system to generate two
or three times more power than originally thought.  Conversely,
another application is to reverse current flow and use the tether in
an electric-motor mode to create thrust for boosting spacecraft in
orbit.  Again, the force generated is directly proportional to current
and was well in excess of predictions.

  Another successful study was how gas from the satellite's thrusters,
moving rapidly through Earth orbit, interacts with the ionosphere, the
electrically charged region of the upper atmosphere.  The environments
around the orbiter and satellite were substantially modified by
neutral gas emissions, and ionization of the gas at the satellite
greatly enhanced the current capacity of the system.

For the first
time, measurements were made of the high-voltage plasma sheath, or
ionized shock wave, around a satellite.  Although essentially
impossible to study in the laboratory and difficult to mathematically
model, this phenomenon affects satellites, including those in much
higher orbits, such as communications satellites.  Also, the TSS
deployment created the world's longest antenna in space.  Scientists
hope to analyze emissions from the TSS that may have been picked up by
receivers at a ground site.

   Although satellites have been flying in space for 40 years, aspects
of the interaction of a moving body as it cuts through the plasma
environment are still unclear.  Another first is the collection of a
rich data set on these plasma wakes, which are somewhat similar to the
wake made by a boat moving through water.  TSS has given researchers a
unique opportunity to study this very fundamental interaction.  This
knowledge is important to understanding many types of measurements
made by spacecraft and also applies to celestial bodies, such as the
interaction of the moon with the solar wind -- a stream of electrons
and charged hydrogen atoms that flows past the Earth at speeds over
180 miles per second (300 kilometers per second).

  Meanwhile, the scientific harvest for the third United States
Microgravity Payload (USMP-3) research team topped the 100-percent
mark, thanks to a bonus day in space for their experiments.  USMP-3
researchers, who had already won their "game," scored extra points by
gathering additional data with which to better understand materials
processing and fire-related phenomena in space.  The ultimate benefit
of USMP-3 research will be improvements in products manufactured on
Earth.  "I couldn't be happier.  The science we've obtained is
fundamental to a lot of processes that are very important to all of
us," concluded USMP-3 Mission Scientist Dr. Peter Curreri.

  During the eight and one-half day dedicated microgravity science
phase of STS-75, USMP-3 researchers used an effective combination of
remote control, or "telescience," for materials processing and
thermodynamic experiments, and hands-on work with combustion studies
performed in the Middeck Glovebox.  Telescience will be increasingly
important for long-term research in space, such as aboard the
International Space Station.

  The MEPHISTO science team, led by Dr. Jean-Jacques Favier of
France's Center for Nuclear Study, used flight-proven equipment to
learn how the chemical composition of molten material changes, and can
be controlled, as they solidify.  Such knowledge applies to
ground-based materials processing and chemical engineering.  For the
first time, the changes in the microgravity environment caused by
carefully planned Shuttle thruster firings were correlated with fluid
flows in a crystal sample.  With the help of data from the Space
Acceleration Measurement System on board Columbia, research showed
that in one direction of movement, a large effect was noted, whereas
in another direction, there was little impact.  Such information is
important in future designs and experiment planning for similar
facilities aboard the International Space Station.  Also, the MEPHISTO
team successfully monitored the point at which their sample's crystal
edge underwent a key change -- from flat to grooved -- as it
solidified.

  During each cycle, the MEPHISTO experiment's high-temperature
furnace melted and re-solidified a tin-bismuth mixture representative
of alloys found in airplane turbine blades, electronic materials and
many other products.  The ability to remotely command the MEPHISTO
experiment let the science team use a new strategy to improve data on
the stability of their sample's shape.  This involved tracking small
changes in the speed of sample growth during several furnace operating
cycles.  After finishing its final run on Thursday, one sample was
flash-cooled to preserve it for microscopic analysis.  Measurements
from the MEPHISTO facility -- one in a series of cooperative
investigations between NASA, the French Space Agency and the French
Atomic Energy Commission -- will now be analyzed, along with the final
metallic samples, in order to increase understanding of subtle changes
that occurred during the samples' cooling and solidification.

  The Advanced Automated Directional Solidification Furnace (AADSF)
team, led by Dr. Archie Fripp of NASA's Langley Research Center,
completed more science than they had hoped to accomplish.  In the
AADSF, three lead-tin-telluride crystals were grown while Columbia
orbited in three different attitudes, to determine how these
orientations affect crystal growth.  This knowledge is expected to
help researchers develop processes and semiconductor materials that
perform better and cost less to produce.  It is also likely to lead to
future furnace experiments aboard the Space Station, where crystal
growth directions are subject to change.  In addition to planned
experiments, they got the added bonus of new data at their crystal's
freezing point and an unintended, but interesting, marker in the
growth of their first crystal caused by an unscheduled Shuttle
thruster firing.

  A team from Rensselaer Polytechnic Institute (RPI) and NASA's Lewis
Research Center, designed the Isothermal Dendritic Growth Experiment
(IDGE) to provide high-quality data on the solidification of a
material that imitates the characteristics of common metals and
alloys.  The team collected twice the data they needed, which will
significantly improve statistical analysis.  Knowledge gained from
this experiment will help improve Earth-based processes such as metal
casting, welding and production of aluminum, steel and copper.  The
ability to perform real-time materials science in space has already
shown IDGE investigators that variations in Columbia's microgravity
environment did not affect variations in the speed of dendrite growth.
This finding will allow materials scientists to refine theories of how
tiny, pine-tree-shaped crystals, called dendrites, form as metals
solidify.

  The IDGE team also participated in an important technology
demonstration by commanding a microgravity space instrument from a
remote site located at RPI.  This first-ever remote commanding to the
Shuttle from a U.S. university campus foreshadows operations aboard
the International Space Station.  "This was an important operational
experiment, as well as a significant science experiment," emphasized
Principal Investigator Dr. Martin Glicksman.

  Investigators for the Critical Fluid Light Scattering Experiment, or
Zeno, led by Dr. Robert Gammon of the University of Maryland, were
successful in observing, with unprecedented clarity, xenon's critical
point behavior -- the precise temperature and pressure at which it
exists as both a gas and a liquid.  On Thursday, the experiment which
measures changes in laser light scattering due to variations in the
xenon sample's density, completed the long, methodical approach to the
critical point.  After nearly 14 days of stepping through a series of
tiny decreases in temperature, the team reached the peak of "Mount
Zeno."  The transparent xenon sample displayed the unusual critical
point condition, with maximum light scattering followed by a sudden
increase in cloudiness.  This effect was much more distinctive than
observed during the USMP-2 mission (STS-62) and happened at a lower
temperature than previously thought.

  "We've been to the top, did our flyover of Mount Zeno, and have
actually seen the highest count rates from this sample that we've ever
seen anywhere," emphasized Dr. Gammon.  "There's no other system that
lets you approach this kind of intensity of thermal fluctuation -- you
just can't do this on the ground."  Dr. Gammon further compared the
critical point to the violent reactions in the Sun's core and at the
beginning of the universe when condensed matter expanded to the states
observed today.  Knowledge from this experiment will prove valuable
for applications from liquid crystals to superconductors.

  While USMP-3 remote commanding was in progress in Columbia's cargo
bay, crew member work in conducting Middeck Glovebox investigations
went so smoothly that all combustion samples on board were processed,
both primary and spares.  This, combined with the combustion
researchers' ability to monitor and change procedures in progress,
enabled the combustion team to obtain more than 125 percent of their
planned science.  A further bonus came with crew support for
performing some post-experimentation Glovebox evaluation procedures.
Valuable engineering information that was gathered will be used to
verify Glovebox performance in low-gravity with what had been seen on
the ground.  The versatile Glovebox and the Forced Flow Flamespreading
Test experiment are slated for flight aboard the Russian space station
Mir later this year.  The Glovebox is also one of the facilities
planned for the International Space Station.

  The Forced Flow Flamespreading Test (FFFT), conducted by Kurt
Sacksteder of NASA's Lewis Research Center, processed 16 paper
samples, both flat and cylinder-shaped.  Video of the cylinder-shaped
samples showed significant differences in flame size, growth rate and
color with variations in air flow speed and fuel temperature.  In
post-flight analysis, the flame behavior will be compared with that of
ground simulations to aid in better control and prevention of fires.

  The Comparative Soot Diagnostics (CSD) investigation led by
Dr. David Urban, also of the Lewis Center, completed 25 combustion
experiment runs, 10 more than originally planned.  The CSD team
obtained excellent results, testing the effectiveness of two different
smoke-sensing techniques, for detecting fires in microgravity aboard
the Shuttle and the International Space Station.  Both detectors
responded to smoke from all the burning samples.  Post-flight analysis
involves examination of smoke particles with an electron microscope to
obtain a more complete comparison of the two detectors' performance.

  The Radiative Ignition and Transition to Spread Investigation
(RITSI) team, led by Dr. Takashi Kashiwagi of the National Institute
for Standards and Testing, reported observing new combustion
phenomena, such as "tunneling" flames which move along a narrow path
instead of fanning out from the burn site.  Also, for the first time,
these investigators studied the effects of sample edges and corners on
fire spreading in microgravity.  The RITSI group likewise successfully
conducted 15 planned and 10 extra sample burns.  Data obtained will be
compared with computed predictions as part of efforts to further
reduce the dangers posed by the possibility of fires aboard
spacecraft.

 On Friday, March 8, 1996, 5 p.m. CST, STS-75 MCC Status Report #30
reports: 

  Space Shuttle Columbia's astronauts were scheduled to awaken about
10:30 p.m. Friday night to begin preparations for a Saturday landing,
concluding over two weeks of science operations in space.  Shuttle
managers earlier today elected to pass up landing at the Edwards Air
Force Base in California Friday in the hope that improving weather at
Kennedy Space Center in Florida would allow for a landing there
Saturday.

  Early Saturday, Columbia's astronauts will prepare the vehicle for
entry, packing up gear aboard the shuttle, closing the payload bay
doors and getting into their launch/entry suits.

  The first opportunity Saturday for a KSC landing comes on orbit 250
with a deorbit burn at 5:23 a.m. CST and a landing at 6:24 a.m. CST.
The second KSC opportunity is at 7:59 a.m. CST and the final
opportunity in Florida comes at 9:35 a.m.  Edwards landing
opportunities Saturday morning are at 9:26 and 11:01 CST.

  STS-75 Flight Day 17 Highlights:

 On Saturday, March 9, 1996, 8:30 a.m. CST, STS-75 MCC Status Report #31
reports: 

  Space Shuttle Columbia completed a 16-day science mission this
morning with a landing at 7:58 a.m. CST at the Kennedy Space Center in
Florida.  An early landing opportunity this morning was passed over
because of cloudy conditions at the landing site, but weather
conditions improved for the one-orbit later end of mission.

  The seven-member flight crew will return to Houston to a welcoming
ceremony at Ellington Field Saturday mid-afternoon at the Hangar 990
area.  The event is open to the public.  This recording will be
updated later today as the crew return time becomes known.

  Columbia's flight covered approximately six and a half million miles
in 251 orbits of the Earth.  It was the 75th mission of the Shuttle
program and Columbia's 19th trip into space.  Originally scheduled to
end Thursday, the flight was first extended one day to gain additional
science time on orbit and extended until Saturday after landing
opportunities Friday were missed due to unacceptable weather in
Florida.

  Columbia's entry ground track took it across Mexico, the center of
Texas and Louisiana before tracking over the Gulf of Mexico on its way
to the Florida landing site.  The orbiter's main gear touched the
runway at 7:58 a.m. and 21 seconds.

<end of mission>

Mission Name: STS-76 (76)
  Atlantis (16)         
  Pad 39-B (35)
  76th Shuttle Mission
  3rd MIR Docking
  16th Flight OV-104
  Night Launch (13)
  EVA
  EAFB Landing
  1st Launch and Landing using new MCC

 NOTE: Click Here for Countdown Homepage

Crew:
  Kevin P. Chilton (3), Commander
  Richard A. Searfoss (2), Pilot
  Shannon W. Lucid (5), Mission Specialist
  Linda M. Godwin (3), Mission Specialist
  Michael R. Clifford (3), Mission Specialist
  Ronald M. Sega (2), Mission Specialist

  Shannon W. Lucid will remain on MIR

Milestones:
     OPF -- 11/20/95  (Reference KSC Shuttle Status 11/21/1995)  
     CEIT - 2/8/96 (Reference KSC Shuttle Status 2/09/1996)  
     VAB -- 2/19/96 (Reference KSC Shuttle Status 2/20/1996)  
     PAD -- 2/28/96 (Reference KSC Shuttle Status 2/29/1996)  
     CTDT - 3/5/96 (Reference KSC Shuttle Status 3/06/1996)  
     FRR -- 3/11/96 (Reference KSC Shuttle Status 3/12/1996)  

Payload:
 S/MM-03, SPACEHAB-SM, SAREX-II, MEEP (PPMD, ODC, POSA-I, POSA-II), TRIS (GAS),WNE, KidSat  

Mission Objectives:
  The primary mission objective will be the third docking between
the Space Shuttle Atlantis and the Russian Space Station Mir.  It
will include a crew transfer, an extravehicular activity (EVA), 
logistics operations and scientific research.

  Rendezvous and docking with Mir is scheduled to occur on flight
day three using the same approach as previously used during STS-74.
Docking will occur between the Orbiter Docking System in the forward
area of Atlantis' payload bay and the Docking Module installed during
STS-74 on Mir's Kristall module docking port.

  The mission will also feature a SPACEHAB module, middeck
experiments, a Get Away Special (GAS) canister and a 6-hour EVA.
Over 1,900 pounds (862 kilograms) of equipment are being transfered
from Atlantis to Mir including a gyrodyne, transformer, batteries,
food, water, film and clothing.

  Planned Experiments include the Mir Electric Field Characterization
(MEFC) experiment, numerious European Space Agency's (ESA) Biorack
life sciences experiments, the Queen's University Experiment in Liquid
Diffusion (QUELD) experiment, the Optizone Liquid Phase Sintering
Experiment (OLIPSE) and a Naval Research Laboratory (NRL) Get Away
Special (GAS) payload Trapped Ions in Space (TRIS) experiment.  TRIS
will measure low-energy particle radiation in the inner magnetosphere.
Another experiment conducted on Mir during STS-76 will be the 
Mir Wireless Network Experiment (WNE) which was launched on STS-74 in
November 1995.  It will test the first wireless client-server network
in the space environment.

  The mission will also include KidSat, a prototype of Earth viewing
cameras and instruments that allows students in grades Kindergarden to
Grade 12 (K-12) to see and direct the capture of pictures from space.

  Mission Specialists Godwin and Clifford are also scheduled to perform a
six-hour spacewalk on flight day six.  They will attach four
experiments, known collectively as the Mir Environmental Effects
Payload MEEP, onto handrails located on the Mir Docking Module.
These experiments include the Polished Plate Micrometeoriod Debris
(PPMD) experiment, the Orbital Debris Collector (ODC) experiment, and
the Passive Optical Samples (POSA) I and II experiments.

Launch:  
  Launch March 22, 1996 at 3:13:04 a.m. EST.  Launch Window was 7 min.

  The countdown began at the T-43 hour mark at 2 a.m. Monday, March
18th, 1996. (Reference KSC Shuttle Status 3/14/1996).  The countdown
was conducted from Firing Room 1 of the Launch Control Center
(LCC) and included 30 hours and 33 minutes of build-in holds.
(Reference KSC Press Release 32-96).  The launch countdown proceeded
smoothly and launch occured exactly on time at the start of the 
available window.  During ascent, the only problem noted was a small
leak of hydraulic fluid from the hydraulic system powered by APU # 3.
(Reference STS-76 MCC Status Report #1)

  Post flight inspections of the mobile launcher platform (MLP) at
Pad 39-B revealed a 63 foot long crack on one of the MLP steel plates 
running from the north end of the left-hand flamehole to the north end
of the MLP surface.  Cracks are sometimes found and easily repaired on
the MLPs following launch operations.  No impact to later scheduled
launches is expected.  MLP-3 will next be used for Mission STS-79 in
July. (Reference KSC Shuttle Status 3/25/1996).

  On 3/20/96, the Rotating Service Structure (RSS) at Launch Pad-39B was 
rolled back and external tank fueling operations were set to begin for a 
launch at 3:34am EST 3/21/96. However, there were high winds and rough
seas in the launch area which would violate RTLS constraints at the 
Shuttle Landing Facility. Weather forecasts showed only a 20% chance of 
favorable weather.  (Reference KSC Weather History 03/20/1996 1800).  The 
shuttle mission management team decided at 6:45pm to delay the launch 24 hours 
with a new T-0 at 3:12 a.m. EST on 3/22/96. (Reference KSC Shuttle Status 3/21/1996).

  The Payload interface verification tests were completed 3/12/96 and
the payload bay doors closed for fight.  The Flight Readiness Review
and the mission management team selected March 21, 1996 as the official
launch date. (Reference KSC Shuttle Status 3/12/1996).

  The Spacehab single module has been installed into the payload bay and
connected to the tunnel adapter. The Space Shuttle main engine flight
readiness test was conducted 3/1/96. The Helium signature test was done
on 3/4/96. The STS-76 crew arrived at KSC 3/3/96 at about 8 p.m. for the
Terminal Countdown Demonstration Test (TCDT) with a simulated engine
cut-off at 11am 3/6/96. (Reference KSC Shuttle Status 3/04/1996).

  On 11/27/95, Post flight access was being established.  The payload
bay doors were opened in preparation for removing the Orbiter Docking
System data analysis is complete with no issues or concerns.
(Reference KSC Shuttle Status 11/27/1995).

Orbit:
  Altitude:   160 nm
  Inclination: 51.6  degrees
  Orbits:  145 (estimated)
  Duration:  9 days, 5 hours, 16 minutes, 48 seconds. 
  Distance:  3.8 million miles (estimated)

Hardware:
  SRB: BI-79
  SRM:
  ET :  SN-77
  MLP : 3
  SSME-1: SN-2035
  SSME-2: SN-2109
  SSME-3: SN-2019

Landing:  
  Edwards AFB March 31, 1996 at 8:28:57 a.m. EST.  Runway 22.
Conditions at EAFB were clear and calm with no weather concerns.
Landing was 11min before daylight at 5:29am local time which
under flight rules is considered a daylight landing.  The deorbit burn
fired at 7:24 a.m EST.  Atlantis executed a 275degree left overhead
turn into the landing strip and twin sonic booms were heard at Edwards
3min before landing.  Main Gear Touchdown at 9 days 5 hours 15 min 53 sec
or 8:28:57 EST.  Nose gear touchdown at a MET of 9 days 5 hrs 15 min 4 sec
or 8:29:08 EST and wheels stop at 9 days 5 hours 16 min 48 sec or 8:29:52 EST.

  Time critical science experiments were removed while Atlantis was
on the runway and the orbiter was towed from the runway at 5:35pm EST.
Towing was completed by 7:23pm EST. (Reference KSC Shuttle Status 4/01/1995).
Residual cryogenic reactants were offloaded and technicians entered the
aft main engine compartment to inspect the hydraulic system.
(Reference KSC Shuttle Status 4/02/1995).

  The decision to aim Atlantis toward the one-day-early landing in
Florida was made by shuttle managers on 3/28/96. KSC was the only
landing site considered for Saturday, 3/30/96 however the landing
opportunities were waived off due to trends of clouds forming to the
south of the Shuttle Landing Facility.  KSC landings on Sunday
3/31/96 would have required a deorbit burn on orbit 143 at 5:57am EST 
or 7:33am EST and led to landings at either 7:00am EST or 8:29am EST.
The KSC landings were waived off due to weather.
(Reference KSC Weather History 03/31/1996 0700).

  Three landing opportunities existed for a Sunday landing at Edwards
Air Force Base on orbits 144, 145 and 146.  The three Edwards
opportunities were: an orbit 144 deorbit burn at 7:25 a.m. EST with a
8:29 a.m. EST landing; an orbit 145 deorbit at 9:02 EST a.m. landing
at 10:06 EST; and an orbit 146 engine firing at 10:38 EST a.m. landing
at 11:42 a.m EST.  (Reference STS-76 MCC Status Report #17)

  Weather conditions Sunday at KSC were a concern. Early morning ground
fog, scattered clouds at 1000 ft and thunderstorms within 30 miles of
the landing strip. Weather at Edwards Air Force Base was predicted to
be acceptable on Sunday.  A total of five opportunities were present
for a Sunday landing, two to KSC and three to Edwards.  
(Reference STS-76 MCC Status Report #16)

  After the landing opportunity on Saturday was waived off, the crew
was given the go to open Atlantis' payload bay doors.  Latches 5 thru
8 on the doors released (starboard side) but latches 9-12 on the
starbord side not release.  The latching system consists of 16
bulkhead latches (eight aft and eight forward) and 16 payload bay door
centerline latches.  Astronaut Linda Godwin inspected the latches thru
the payload bay door windows and the SpaceHab windows and reported
that the latches appeared to be open.  The astronauts manually commanded
the latches to open and the payload bay doors opened as expected.

  On 4/6/96, the orbiter Atlantis, bolted atop the Shuttle Carrier Aircraft
(SCA), aborted its departure from Edwards Air Force Base, Calif. after
being airborne for only 15 min.  The orbiter/SCA departed EAFB at 4:55 EST
en route back to Kennedy Space Center but about 5 minutes after departure,
the flight crew of the SCA observed a fire warning indicator light for
engine No. 3, the right inboard engine.  Pilots Gordon Fullerton and Tom
McMurtry shut down the engine and returned to Edwards on the remaining
three engines without further incident.  The engine was replaced and
the SCA carrying Atlantis arrived at KSC on 4/12/96
(Reference KSC Shuttle Status 4/9/1996).

Mission Highlights:

  STS-76 Flight Day 1 Highlights:

 On Friday, March 22, 1996, 7 a.m. CST, STS-76 MCC Status Report #1
reports: 

  Atlantis was launched from the Kennedy Space Center on time at 2:13
a.m. CST today to begin Shuttle mission STS-76, the third shuttle
mission to dock with the Russian Mir space station.

  Currently in a 157 by 123 nautical mile orbit, Atlantis is now
trailing Mir by 13,100 nautical miles and closing in on the Russian
station at 694 nautical miles with each hour and a half -long orbit of
Earth.  Docking with the station remains targeted for about 8:34
p.m. CST Saturday.

  Atlantis' crew -- Commander Kevin Chilton, Pilot Rick Searfoss,
Payload Commander Ron Sega, and Mission Specialists Rich Clifford,
Linda Godwin and Shannon Lucid, who will join two cosmonauts as a
member of the Mir-21 crew after docking -- is now setting up the
shuttle for an extended stay in orbit.  All of Atlantis' systems
are currently functioning well.

   Flight controllers did notice an apparent small leak of hydraulic
fluid from one of three hydraulic systems aboard the shuttle shortly
after liftoff. The hydraulic systems are only used during launch and
landing, and the leak from the backup system was observed only while
that system was in operation during the climb to orbit. When all three
hydraulic systems were shut down after reaching orbit, as is normal,
no further indications of a leak were observed.

  Only two hydraulic systems are actually needed for the shuttle to
land safely, although flight controllers prefer to have all three
operating to ensure a backup system is available in the event of a
problem.  Shuttle managers believe it is unlikely that the leak in the
backup system will cause any change to the planned mission, although
they are continuing to evaluate the situation.

  The leaking hydraulic system, which is powered by Auxiliary Power
Unit 3 aboard Atlantis, still has sufficient hydraulic fluid to be
used during landing operations, the next time it would normally be
powered up.  None of the hydraulic systems are needed for Atlantis'
operations in orbit, and flight controllers have ample time to analyze
the leaking system and assess any impact it could have on the flight.

 On Friday, March 22, 1996, 5:30 p.m. CST, STS-76 MCC Status Report #2
reports:

  Closing on the Russian Space Station Mir at a rate of 661 nautical
miles per orbit, the STS-76 crew will perform several rendezvous burns
today as the third Shuttle docking mission proceeds as planned.

  This afternoon, the Mission Management Team met in Houston to
discuss a leak seen in one of the hydraulic systems during the ascent
portion of the flight. After an examination of the data, engineers
concluded that the leak began as the high pressure hydraulic fluid
system pumps were started shortly before launch. Data showed a leak
rate of about 1 percent of the system's total reservoir per minute
leading flight controllers to believe that about 20 percent of the
reservoir leaked from the system.

  The leak stopped when the system was shut down after ascent, and no
further leakage has been detected.  Since the leak only appears while
the system is operating, mission managers are confident that the
system will remain stable on orbit, and that there is no reason to
change the duration of the mission.  Controllers will continue to
monitor the system for any changes in its status.

  Today, crew members will configure the SpaceHab module for its
on-orbit operations, check out the spacesuits that will be used by
Mission Specialists Rich Clifford and Linda Godwin later in the
flight, and test the equipment that will be used for the rendezvous
operations.

  The crew began its day today at 3:13 p.m. Central with the song
"Anywhere Is" by Enya. Atlantis, making its 16th flight, is performing
well as it circles the Earth in a 159 by 127 n.m. orbit.

  STS-76 Flight Day 2 Highlights:

 On Saturday, March 23, 1996, 5 a.m. CST, STS-76 MCC Status Report #3
reports: 

  STS-76 Commander Kevin Chilton and Pilot Rick Searfoss fired
Atlantis' orbital maneuvering system jets just before 3:30 a.m. today,
refining its path for this evening's rendezvous with the Mir Space
Station.

  This morning's burn slowed the rate at which Atlantis is closing on
Mir, and raised the high point of its orbit to 210 nautical miles in
anticipation of the terminal initiation burn that will position
Atlantis to intercept the space station. Currently Atlantis trails Mir
at a distance of about 3,000 nautical miles, closing the distance by
about 400 nautical miles every 90 minutes.

  Throughout the night and into the early morning hours, the six
astronauts prepared for their docking with Mir, checking out the radio
communications equipment they will use during their approach. Mission
Specialists Linda Godwin and Rich Clifford also checked out the space
suits they will wear during Wednesday's planned six-hour EVA. The
suits and hardware have been temporarily stowed in Atlantis' airlock.

  Chilton, Searfoss and Mission Specialist Shannon Lucid also spent
time this morning discussing the progress of their mission and Lucid's
planned stay on the Mir Space Station with NBC's Nightside
program. Lucid told Nightside host Tom Miller that she believed her
four-month stay on Mir "will be a great adventure."

  The astronauts will begin a 7-hour sleep period at 7:13 a.m. central
time today before waking to begin final rendezvous and docking
activities. About one hour after waking up, Chilton and Searfoss will
fire Atlantis' maneuvering system engines in the final phasing burn
designed to further slow Atlantis' closing rate to 34 nautical miles
per orbit. One orbit later, Atlantis will be eight miles away from
Mir, in position for the terminal initiation burn that allows Atlantis
to intercept the Russian space station.

  Chilton will initiate the TI burn at 5:52 p.m. central time, moving
Atlantis along a precise course to meet up with Mir. Atlantis will
stationkeep at a distance of 170 feet from Mir while flight
controllers in Houston and Moscow confer before giving a final "go"
for docking operations. Docking is targeted for 8:34 p.m. today.

  All systems are continuing to perform well as Atlantis makes its 16th
journey into space.

  STS-76 Flight Day 3 Highlights:

 On Sunday, March 24, 1996, 1 a.m. CST, STS-76 MCC Status Report #4
reports: 

   Following a flawless rendezvous, Atlantis successfully docked to
the Russian Mir space station as Commander Kevin Chilton gently guided
Atlantis to a linkup at 8:34 PM Central time Saturday night.

  A little less than two hours later, Mission Specialist Rich Clifford
completed safing and pressurizing Atlantis' docking vestibule and the
hatches were opened between the two spacecraft as Atlantis' crew was
greeted by Mir 21 Commander Yuri Onufrienko and Flight Engineer Yuri
Usachev.  Shortly after the hatch opening and initial greetings, the
shuttle crew moved into the Mir and astronaut Shannon Lucid officially
became the third member of the Mir-21 crew, embarking on a 4 1/2 month
stay in space to inaugurate a permanent U.S. presence in space on Mir
for the next two years. Lucid will be replaced by astronaut John Blaha
in August. Onufrienko and Usachev were launched on a Soyuz rocket to
the Mir on February 21st. They'll return to Earth in July after a
replacement crew of Russian cosmonauts and a French researcher joins
Lucid aboard the Mir.

  As is traditional, the crews exchanged gifts during a short
welcoming ceremony in the Mir Core module, with the Mir crew giving
Atlantis' astronauts a variety of placards and memorabilia. Atlantis'
crew gave the cosmonauts commemorative shirts, chocolate Easter
bunnies and two books, including autographed copies of Apollo 13
Commander Jim Lovell's "Lost Moon," on which the movie "Apollo 13" was
based. Chilton described the rendezvous, docking and initial moments
on the Mir as "unreal."

  Following safety briefings for both crews on each other's respective
spacecraft, the astronauts and cosmonauts began transferring more than
a ton of water, Russian supplies, science equipment and other gear
from the shuttle to Mir. The transfer of equipment will continue
through much of the five days Atlantis is docked with the Mir.

  Early Wednesday morning, while Atlantis is still docked to the Mir,
Clifford and Mission Specialist Linda Godwin will perform a six-hour
spacewalk outside Atlantis to affix four experiment packages to the
exterior of the Mir docking module.

  The 230-ton Atlantis-Mir complex is orbiting the Earth every 90
minutes at an altitude of about 240 statute miles with all systems on
both craft operating normally.

 On Sunday, March 24, 1996, 11 a.m. CST, STS-76 MCC Status Report #5
reports:

  A long-term, continuous U.S. presence on Russia's Mir space station
was inaugurated early Sunday with the transfer of astronaut Shannon
Lucid to the Mir 21 crew.  The two spacecraft linked up in orbit at
8:34 p.m. CST Saturday for five days of joint operations.

  Lucid is embarking on a 4 1/2 month stay in space, joining Mir 21
Commander Yuri Onufrienko and Flight Engineer Yuri Usachev.  Lucid is
the second U.S. astronaut to make an extended visit to Mir as part of
Phase 1 of the International Space Station Program.

  The point of her transfer to the Mir crew occurred when the seat
liner she would use in the event of a return to Earth in the Soyuz
capsule was moved to the Mir.  Official assignment of Lucid to the Mir
21 crew came at 7:30 a.m. central time today after Flight Director
Bill Reeves in Houston and Nikolai Nikiforov in Mission Control,
Moscow, gave a joint 'go' statement.

  The astronauts and cosmonauts have begun transferring more than a
ton of water, Russian supplies, science equipment and other gear from
the shuttle to Mir. The transfer of equipment will continue through
much of the five days Atlantis is docked with the Mir.

  The crew is now asleep, having begun a 10-hour sleep period at 8:43
a.m. central time today.  Astronauts will wake at 6:43 p.m. to begin
Flight Day 4.

  Early Wednesday morning, while Atlantis is still docked to the Mir,
astronauts Rich Clifford and Linda Godwin will perform a six-hour
spacewalk outside Atlantis to attach four experiment packages to the
exterior of the Mir docking module.

  The Shuttle and its now five person crew is expected to return to
Earth March 31 with a 6:03 a.m. CST landing at Kennedy Space Center,
Florida.

  The 230-ton Atlantis-Mir complex is orbiting the Earth every 90
minutes at an altitude of about 240 statute miles with systems on both
craft operating normally.

  STS-76 Flight Day 4 Highlights:

 On Monday, March 25, 1996, 7 a.m. CST, STS-76 MCC Status Report #6
reports: 

  Transfer and resupply activities on board the joined Atlantis/Mir
spacecraft continue on or ahead of schedule as the eight astronauts
and cosmonauts work smoothly through their timeline.  Throughout the
night and early morning hours, the crews moved between the two
vehicles transferring water, logistical supplies and hardware.
Mission Specialist Linda Godwin also continued her work with the
European Space Agency Biorack which contains 11 separate scientific
investigations.

  Just before 2:30 a.m. central time today, Pilot Rick Searfoss narrated
a videotaped tour of the Mir complex which will be home to Shannon
Lucid and her Mir 21 crew mates -- Commander Yuri Onufrienko and Yuri
Usachev -- for the next few months.  Godwin and Mission Specialist Ron
Sega then provided a video update of their work with the Biorack
investigations and showed some of the transfer items currently stowed
in the SpaceHab module.

  Shortly after 8 a.m., Atlantis Commander Kevin Chilton, Onufrienko
and Lucid will talk with NASA Administrator Daniel Goldin in
Washington, D.C.  Goldin is expected to congratulate the crew on the
successful docking of the two spacecraft.  The Atlantis crew will
begin an eight-hour sleep period at 10:43 a.m. today, waking up at
6:43 p.m.

 On Monday, March 25, 1996, 5 p.m. CST, STS-76 MCC Status Report #7
reports:

  Astronauts aboard Space Shuttle Atlantis were due to awaken at 6:43
p.m. CST to begin flight day five of the 76th shuttle mission.

  Coming up late Monday and early Tuesday are continued transfer of
water, supplies and experiment hardware to Mir and preparations
leading up to Wednesday mornings spacewalk.  In the previous flight
day, transfer and resupply activities on board the joined Atlantis/Mir
spacecraft continued on or ahead of schedule as the eight astronauts
and cosmonauts worked smoothly through their timeline.

  Throughout the night and early morning hours, the crews moved
between the two vehicles transferring water, logistical supplies and
hardware.  Mission Specialist Linda Godwin also continued her work
with the European Space Agency Biorack which contains 11 separate
scientific investigations.

  Just before 2:30 a.m. central time Monday, Pilot Rick Searfoss
narrated a videotaped tour of the Mir complex which will be home to
Shannon Lucid and her Mir 21 crew mates -- Commander Yuri Onufrienko
and Yuri Usachev -- for the next few months.  Godwin and Mission
Specialist Ron Sega then provided a video update of their work with
the Biorack investigations and showed some of the transfer items
currently stowed in the SpaceHab module.

  Shortly after 8 a.m., Atlantis Commander Kevin Chilton, Onufrienko
and Lucid talked with NASA Administrator Daniel Goldin in Washington,
D.C.  Goldin congratulated the crew on the successful docking of the
two spacecraft.

  STS-76 Flight Day 5 Highlights:

 On Tuesday, March 26, 1996, 6 a.m. CST, STS-76 MCC Status Report #7
reports: 

  Atlantis' astronauts viewed Comet Hyakutake early this morning as it
continued its close pass by Earth, and they told reporters the comet
was brilliant and could be seen almost from horizon to horizon.

  The comments came during an in-flight press conference with the
Atlantis/Mir crews taking questions from reporters at NASA centers and
in Russia.  Although reporting that their glimpse of the comet was
spectacular, the crew has not yet been able to capture it on
televison. The astronauts and cosmonauts also took time out from their
transfer and resupply activities to talk with Charlie Gibson of
'Good Morning America' shortly after 4 a.m. central time today.

  For much of the first half of their day, the crew members continued to
transfer water, supplies and science equipment between the two
spacecraft.  More than 1,000 pounds of water, in 10 water containers,
has been moved to the Mir space station to provide drinking and
bathing water for the Mir 21 crew.

  The last half of the Atlantis crew's day was devoted to preparing for
Wednesday morning's six-hour spacewalk by Linda Godwin and Rich
Clifford. The hatches between Atlantis and Mir were closed, as was the
hatch between Atlantis and the SpaceHab module. The astronauts then
depressurized the Shuttle's cabin from its standard 14.7 pounds per
square inch to 10.2 psi, a standard pre-spacewalk protocol.  At the
same time, Godwin and Clifford breathed pure oxygen to begin the
process of purging nitrogen from their bodies for the spacewalk. The
SpaceHab and Shuttle-Mir hatches will remain closed until the
spacewalk is completed.

  The two spacewalkers currently are scheduled to float out of
Atlantis' airlock just after midnight, marking the start of the
first extravehicular activity to be conducted around the Mir by
American astronauts.  During the spacewalk, four experiment containers
designed to characterize the environment around Mir will be attached
to handrails on the space station.  The packages will be retrieved in
a subsequent spacewalk in about 18 months and will provide information
on the quantity and type of orbital debris and contaminants found in
the same general altitude and orbital inclination planned for the
International Space Station.

  The Atlantis-Mir complex continues to orbit the Earth every 90 minutes
at an altitude of about 240 statute miles with systems on both
spacecraft operating normally.

 On Tuesday, March 26, 1996, 5 p.m. CST, STS-76 MCC Status Report #9
reports: 

  At 5 p.m. Tuesday, Atlantis' astronauts were nearing the end of
their sleep period, due to awaken at 6:43 p.m.  Preparations for the
spacewalk by astronauts Rich Clifford and Linda Godwin begin at
approximately 8:45 p.m. CST.

  The hatches between Atlantis and Mir were closed early Tuesday, as
was the hatch between Atlantis and the SpaceHab module. The astronauts
then depressurized the Shuttle's cabin from its standard 14.7 pounds
per square inch to 10.2 psi, a standard pre- spacewalk protocol.  At
the same time, Godwin and Clifford breathed pure oxygen to begin the
process of purging nitrogen from their bodies for the spacewalk. The
SpaceHab and Shuttle-Mir hatches will remain closed until the
spacewalk is completed.

  The two spacewalkers currently are scheduled to float out of
Atlantis' airlock just after midnight, marking the start of the first
extravehicular activity to be conducted around the Mir by American
astronauts.  During the spacewalk, four experiment containers designed
to characterize the environment around Mir will be attached to
handrails on the space station.  The packages will be retrieved in a
subsequent spacewalk in about 18 months and will provide information
on the quantity and type of orbital debris and contaminants found in
the same general altitude and orbital inclination planned for the
International Space Station.

  Atlantis' astronauts viewed Comet Hyakutake early this morning as it
continued its close pass by Earth, and they told reporters the comet
was brilliant and could be seen almost from horizon to horizon.

  The comments came during an in-flight press conference with the
Atlantis/Mir crews taking questions from reporters at NASA centers and
in Russia. The astronauts and cosmonauts also took time out from their
transfer and resupply activities to talk with Charlie Gibson of "Good
Morning America" shortly after 4 a.m. central time today.

  The Atlantis-Mir complex continues to orbit the Earth every 90
minutes at an altitude of about 240 statute miles with systems on both
spacecraft operating normally.

 On Tuesday, March 26, 1996, 5 p.m. CST, STS-76 MCC Status Report #9
reports: 

   At 5 p.m. Tuesday, Atlantis' astronauts were nearing the end of
their sleep period, due to awaken at 6:43 p.m.  Preparations for the
spacewalk by astronauts Rich Clifford and Linda Godwin begin at
approximately 8:45 p.m. CST.

  The hatches between Atlantis and Mir were closed early Tuesday, as
was the hatch between Atlantis and the SpaceHab module. The astronauts
then depressurized the Shuttle's cabin from its standard 14.7 pounds
per square inch to 10.2 psi, a standard pre- spacewalk protocol.  At
the same time, Godwin and Clifford breathed pure oxygen to begin the
process of purging nitrogen from their bodies for the spacewalk. The
SpaceHab and Shuttle-Mir hatches will remain closed until the
spacewalk is completed.

  The two spacewalkers currently are scheduled to float out of
Atlantis' airlock just after midnight, marking the start of the first
extravehicular activity to be conducted around the Mir by American
astronauts.  During the spacewalk, four experiment containers designed
to characterize the environment around Mir will be attached to
handrails on the space station.  The packages will be retrieved in a
subsequent spacewalk in about 18 months and will provide information
on the quantity and type of orbital debris and contaminants found in
the same general altitude and orbital inclination planned for the
International Space Station.

  Atlantis' astronauts viewed Comet Hyakutake early this morning as it
continued its close pass by Earth, and they told reporters the comet
was brilliant and could be seen almost from horizon to horizon.

  The comments came during an in-flight press conference with the
Atlantis/Mir crews taking questions from reporters at NASA centers and
in Russia. The astronauts and cosmonauts also took time out from their
transfer and resupply activities to talk with Charlie Gibson of "Good
Morning America" shortly after 4 a.m. central time today.

  The Atlantis-Mir complex continues to orbit the Earth every 90
minutes at an altitude of about 240 statute miles with systems on both
spacecraft operating normally.

  STS-76 Flight Day 6 Highlights:

 On Wednesday, March 27, 1996, 7 a.m. CST, STS-76 MCC Status Report #10
reports:

  Astronauts Linda Godwin and Rich Clifford successfully completed the
first ever spacewalk from a docked Space Shuttle this morning,
installing four experiments on the exterior of the Russian Mir space
station.

  Starting at 12:36 a.m. CST, Godwin and Clifford spent six hours, two
minutes and twenty-eight seconds spacewalking in Atlantis's cargo bay
and on the exterior of the Mir's docking module. They smoothly
performed all of the objectives planned for the spacewalk, the most
important of which was to install the four experiments to monitor the
space environment on the exterior of Mir for the next year and a half.

  The Mir Environmental Effects Payload, as the experiments are called,
were clamped to outside rails on the docking module. They will gather
information on space debris encountered outside the Mir; the amounts
and types of contaminants around the station; and the corrosive
effects of space on various materials. When retrieved and brought back
to Earth, the experiments will provide valuable insight to engineers
about the space environment likely to be encountered by the future
International Space Station.

  Godwin and Clifford also detached a television camera from the
outside of the Mir docking module to return it to Earth, and they
evaluated a variety of new spacewalking tools capable of being used on
both U.S. and Russian spacecraft.

  Shortly after the spacewalk was completed, the hatches between Mir
and Atlantis were reopened, reuniting the two space crews. Atlantis'
crew will begin a sleep period at 10:43 a.m. CST and awaken to begin
Day 7 of their mission at 6:43 p.m. CST.

 On Wednesday, March 27, 1996, 4 p.m. CST, STS-76 MCC Status Report #11
reports:

  The Atlantis astronauts are due to awaken just before 7 p.m. tonight
to begin their final full day of joint docked operations with the Mir
space station.  Transfer of water, supplies and experiment equipment
was nearly completed early Wednesday, moving 1500 pounds of water from
the Atlantis to Mir.

  A farewell ceremony is planned for 4:38 a.m. Thursday, followed by
closing of the hatches at 6:43 a.m.  After the crew's sleep period
during the day Thursday, the orbiter will undock from Mir at
approximately 7 p.m. CST.  Atlantis will fly around Mir for about an
hour and a half, taking photos before firing its engines at 8:53
p.m. and dropping into a lower orbit of about 220 nautical miles.

  Atlantis is expected to return home Sunday, landing at the Kennedy
Space Center in Florida about 6 a.m. CST.  Weather considerations
could alter the landing site or day of landing.

  Earlier Wednesday, astronauts Linda Godwin and Rich Clifford
successfully completed the first ever spacewalk from a docked Space
Shuttle this morning, installing four experiments on the exterior of
the Russian Mir space station.

   Starting at 12:36 a.m. CST, the two spent six hours, two minutes and
twenty-eight seconds spacewalking in Atlantis's cargo bay and on the
exterior of the Mir's docking module. They smoothly performed all of
the objectives planned for the spacewalk, the most important of which
was to install the four experiments to monitor the space environment
on the exterior of Mir for the next year and a half.

  Shortly after the spacewalk was completed, the hatches between Mir
and Atlantis were reopened, reuniting the two space crews.

  STS-76 Flight Day 7 Highlights:

 On Thursday, March 28, 1996, 7:30 a.m. CST, STS-76 MCC Status Report #12
reports:

  The Atlantis and Mir crews bid an emotional farewell to one another
early this morning, in what STS-76 Commander Kevin Chilton called "a
bittersweet moment."

  Shortly after 3 am. CST today, Atlantis and Mir commanders Chilton and
Onufrienko, along with spacewalkers Linda Godwin and and Rich
Clifford, took time out to talk with CBS' "Up to the Minute."
The space flyers discussed the success of their joint mission and the
6-hour spacewalk conducted Wednesday by Godwin and Clifford.

 On Thursday, March 28, 1996, 10 a.m. CST, STS-76 MCC Status Report #13
reports:

  The Atlantis and Mir crews bid an emotional farewell to one another
early this morning, in what STS-76 Commander Kevin Chilton called 'a
bittersweet moment.' Atlantis is now scheduled to undock this evening
and land at 6:57 a.m. CST Saturday at the Kennedy Space Center, one
day earlier than originally planned, to avoid predicted rain and
clouds in Florida on Sunday.

  The eight astronauts and cosmonauts exchanged handshakes and hugs in
the Mir core module, and then praised mission control centers in both
Houston and Kaliningrad for their support throughout the joint phase
of the mission.

  "We just don't believe that in a few minutes the STS-76 crew will go
through the docking module and we'll say farewell," said Mir 21
Commander Yuri Onufrienko. "We will observe each other only through
the portholes -- they'll be looking at us and we'll be looking at
them.  It will be sad to say farewell to such a good team."

  At the start of the farewell ceremony, the Mir crew received a call
from Vladimir Solovyev, Chief Flight Director at Mission Control
Kaliningrad, congratulating the crews on the success of the mission.

  With the official goodbyes complete, the eight astronauts and
cosmonauts spent time together for a more personal farewell between
friends.  Hatches between the Shuttle and Mir were closed for the
final time at about 7:15 a.m. today, in preparation for Atlantis'
undocking at about 7:08 p.m. tonight.

  When the capture mechanism on the docking module releases and
Atlantis moves away from the Mir Space Station, the STS-76 crew will
leave behind former crewmate Shannon Lucid to begin more than four
months of scientific research on board Mir.  Lucid is inaugurating a
continual American presence on board Mir that will continue to
1998. Following tonight's undocking from Mir, Atlantis will fly around
the space station once, instead of twice as previously planned, before
firing its engines and dropping into a lower orbit of about 220
nautical miles altitude. Tonight, the crew also will perform checkouts
of the shuttle's flight control systems and steering jets in
preparation for the Saturday landing.

  Prior to this morning's hatch closure, the crews transferred about
two tons of scientific equipment, logistical material, and resupply
items between the two spacecraft, including 1,507 pounds of water in
15 containers.  They also performed a final check of their inventory
lists to ensure all the transfer activity was complete.

  The decision to aim Atlantis toward the one-day-early landing in
Florida was made by shuttle managers this morning. The Kennedy Space
Center is the only landing site that will be considered on Saturday,
with the primary landing opportunity set to begin with a deorbit
engine firng at 5:53 a.m. CST leading to the 6:57 a.m.  CST
touchdown. A second opportunity to land at KSC also exists on
Saturday, starting with a deorbit burn at 7:29 a.m. CST leading to an
8:33 a.m. CST touchdown. The Saturday weather forecast for Florida
predicts light winds and scattered clouds, good weather for a landing.

  If Atlantis should have to stay in space until Sunday for any
reason, both KSC and Edwards Air Force Base, Ca., would be considered
for a landing. A total of five opportunities are present for a Sunday
landing, two to KSC and three to Edwards.

 On Thursday, March 28, 1996, 8:30 a.m. CST, STS-76 MCC Status Report #14
reports:

  Space Shuttle Atlantis and the Russian Space Station Mir moved
slowly away from each other Thursday night, following an undocking at
7:08 p.m. CST.  Atlantis spent about an hour flying around Mir at a
distance of 600 feet, conducting a photographic survey.  The shuttle
initiated a separation burn at 8:07 p.m. central time, dropping into a
slightly lower orbit and moving ahead of Mir.

  Tonight, the crew also was scheduled to perform checkouts of the
shuttle's flight control systems and steering jets in preparation for
the landing Saturday at the Kennedy Space Center.

  The Atlantis and Mir crews bid an emotional farewell to one another
early Thursday, in what STS-76 Commander Kevin Chilton called "a
bittersweet moment." The eight astronauts and cosmonauts exchanged
handshakes and hugs in the Mir core module, and then praised mission
control centers in Houston and Kaliningrad for their support
throughout the joint phase of the mission.

  With the separation of the two spacecraft, the STS-76 crew leaves
behind former crewmate Shannon Lucid to begin more than four months of
scientific research on board Mir.  Lucid is inaugurating a continual
American presence on board Mir that will continue to 1998.

  Atlantis is now scheduled to land at 6:57 a.m. CST Saturday at the
Kennedy Space Center, one day earlier than originally planned, to
avoid predicted rain and clouds in Florida on Sunday.  The decision to
aim Atlantis toward the one-day-early landing in Florida was made by
shuttle managers Thursday morning. The Kennedy Space Center is the
only landing site that will be considered on Saturday, with the
primary landing opportunity set to begin with a deorbit engine firing
at 5:53 a.m. CST leading to the 6:57 a.m. CST touchdown. A second
opportunity to land at KSC also exists on Saturday, starting with a
deorbit burn at 7:29 a.m. CST leading to an 8:33 a.m. CST
touchdown. The Saturday weather forecast for Florida predicts light
winds and scattered clouds, good weather for a landing.

  If Atlantis should have to stay in space until Sunday for any reason,
both KSC and Edwards Air Force Base, CA, would be considered for a
landing. A total of five opportunities are present for a Sunday
landing, two to KSC and three to Edwards.

  STS-76 Flight Day 8 Highlights:

 On Friday, March 29, 1996, 6:00 a.m. CST, STS-76 MCC Status Report #15
reports:

  With the Mir Space Station some 60 nautical miles behind them, the
Atlantis astronauts are preparing for tomorrow's return to Earth.

  Overnight, Commander Kevin Chilton, Pilot Rick Searfoss and Mission
Specialist Rich Clifford performed a routine checkout of Atlantis'
flight control surfaces, using a circulation pump instead of an
auxiliary power unit to route hydraulic fluid to the ailerons,
elevons, speedbrake and rudder used during reentry. Mission Managers
elected not to power on the APUs prior to entry to preserve them for
use during Atlantis' return to Earth.

  Auxiliary Power Units 1 and 2 will be powered on as they normally
are, with APU3, the system associated with the leaking hydraulic unit,
turned on late in reentry and run in a low pressure, low speed mode
for use only as a backup system if needed.  All three hydraulic
systems are expected to be in good working order to support Atlantis'
landing.

  During a hot-fire test of the orbiter's reaction control system jets
early this morning, three of the 38 primary jets failed, with one
leaking fuel. The crew closed the left aft manifold and stopped the
leak.  The loss of these three jets has no effect on tomorrow's
planned landing since each has at least two jets in the same positions
that can perform the same functions.

  Today, the astronauts will continue stowing some of the final
transfer items received from the Mir-21 crew and the equipment and
checklists they have used during their seven days on orbit as they
ready Atlantis for landing. Mission Specialist Linda Godwin will
continue to work with the European Space Agency Biorack located in the
Spacehab module before closing out the module for the final time
tonight.

  Atlantis is now scheduled to land at 6:57 a.m. CST Saturday at the
Kennedy Space Center. A second opportunity to land at KSC also exists
on Saturday, with an 8:33 a.m. CST touchdown.  Edwards Air Force Base
in California is not being called up to support tomorrow's landing
attempts, but should weather preclude a Saturday landing at KSC, both
sites will be available for a Sunday landing.

  Weather conditions Saturday at KSC are expected to be good for
landing, with only a slight concern for early morning ground fog.
High winds and thunderstorms are expected to move into the area on
Sunday. Weather at Edwards Air Force Base is predicted to be
acceptable on Sunday.  A total of five opportunities are present for a
Sunday landing, two to KSC and three to Edwards.

 On Friday, March 29, 1996, 4:00 p.m. CST, STS-76 MCC Status Report #16
reports:

  Astronauts aboard Space Shuttle Atlantis this afternoon were getting
their final hours of sleep in space before they make final
preparations for Saturday morning's planned landing in Florida.

 Atlantis is now scheduled to land at 6:57 a.m. CST Saturday at the
Kennedy Space Center. A second opportunity to land at KSC also exists
on Saturday, with an 8:33 a.m. CST touchdown.  Edwards Air Force Base
in California is not being called up to support tomorrow's landing
attempts, but should weather preclude a Saturday landing at KSC, both
sites will be available for a Sunday landing.

  Weather conditions Saturday at KSC are expected to be good for
landing, with only a slight concern for early morning ground fog.
High winds and thunderstorms are expected to move into the area on
Sunday. Weather at Edwards Air Force Base is predicted to be
acceptable on Sunday.  A total of five opportunities are present for a
Sunday landing, two to KSC and three to Edwards.

  STS-76 Flight Day 9 Highlights:

 On Saturday, March 30, 1996, 8:00 a.m. CST, STS-76 MCC Status Report #17
reports:

  Space Shuttle Atlantis and its five member crew will remain in orbit
one additional day following the wave-off of two landing opportunities
at Kennedy Space Center today.  Weather for both landing opportunities
was too dynamic to assure flight controllers that it would be
acceptable one hour after having to commit to an entry.  Early morning
fog obscured the landing site on the first opportunity when the
decision had to be made and apparently increasing low clouds made the
second landing try too uncertain for comfort.

Atlantis has five landing opportunities for a return home on Sunday,
two at KSC and three at Edwards Air Force Base, California.  Weather
forecasters and flight controllers will examine expected conditions
for each of those times to determine whether all are usable.  The
first available time is for a 4:47 a.m. CST deorbit burn on orbit 143
with a 6 a.m. landing at Kennedy Space Center. The second and final
KSC opportunity is a 6:33 a.m. CST deorbit burn and a 7:29 CST
landing.

  The three Edwards opportunities are: an orbit 144 deorbit burn at 6:25
a.m. with a 7:29 a.m. landing; an orbit 145 deorbit at 8:02
a.m. landing at 9:06; and an orbit 146 engine firing at 9:38
a.m. landing at 10:42 a.m.  All times are Central.

  Following the wave-off, astronauts were told they could begin backing
out of their deorbit readiness condition, reconfiguring orbiter
systems, opening the payload bay doors and getting out of their suits.

  During the stand-down from entry preparations as the astronauts were
opening the payload doors, there was brief concern when microswitches
which show the position of a set of door centerline latches indicated
that they were not fully open, halting the door opening process.  Open
doors are required to allow the shuttle's radiators to provide
necessary cooling.

  Astronaut Linda Godwin visually compared the latch position with
drawings and described them as appearing to be fully open. Flight
controllers asked the crew to operate switches which manually open the
remaining latches along the starboard door. Once that was done and the
door appeared to open freely, the full door opening process continued
without additional delay.

  The crew will spend the day conducting Earth observations photography
and keeping the orbiter ready for entry.

  Weather conditions Sunday at KSC are potentially the same or worse
than Saturday. Weather at Edwards Air Force Base is predicted to be
acceptable on Sunday.

  STS-76 Flight Day 10 Highlights:

 On Sunday, March 31, 1996, 8:00 a.m. CST, STS-76 MCC Status Report #18
reports:

  Space Shuttle Atlantis returned to Earth early today with a 7:29
a.m. CST landing at Edwards Air Force Base, California.  Weather at
Kennedy Space Center in Florida was uncertain enough to cause the
flight control team to pass up the first and second landing
opportunities at KSC today, selecting Edwards with its excellent, more
stable weather as the landing site.

  Atlantis descent from Earth orbit occurred on orbit 144 with an
engine firing at 6:25 a.m. CST.  The main gear touched down at a
mission elapsed time of 9 days, five hours, 15 minutes and 53 seconds
or 7: 28 and 57 seconds central time this morning.  The spacecraft
covered approximately 3.8 million miles since its launch Feb. 22.

  An early-mission leak in one of three hydraulic systems caused no
difficulty on entry.

  Astronauts Kevin Chilton, Rick Searfoss, Linda Godwin, Ron Sega and
Rich Clifford are expected to return to Houston at approximately 3:30
p.m.  A welcoming ceremony at Ellington Field's Hangar 990 is open to
the public.  A more precise estimate of crew arrival time will be made
later in the day.

<end of mission>

Mission Name: STS-77 (77)
  Endeavour (11)         
  Pad 39-B (36)
  77th Shuttle Mission
  11th Flight OV-105
  Night Launch (14)
  KSC Landing (30)

 NOTE: Click Here for Countdown Homepage

Crew:
  John H. Casper (4), Commander
  Curtis L. Brown Jr. (3), Pilot
  Daniel W. Bursch (3), Mission specialist
  Mario Runco, Jr.(3), Mission Specialist
  Marc Garneau (2), Mission Specialist (CSA)
  Andrew S. W. Thomas (1), Mission Specialist

Milestones:
     OPF -- 1/20/96 (Reference KSC Shuttle Status 1/22/1996)  
     CEIT - 3/26/96 (Reference KSC Shuttle Status 3/26/1996)  
     VAB -- 4/09/96 (Reference KSC Shuttle Status 4/09/1996)  
     PAD -- 4/16/96 (Reference KSC Shuttle Status 4/17/1996)  
     TCDT - 4/23/96 (Reference KSC Shuttle Status 4/24/1996)  
     FRR -- 5/07/96 (Reference KSC Shuttle Status 5/08/1996)

  (Reference KSC Shuttle Status Apr 1996)
  (Reference KSC Shuttle Status May 1996)

Payload:
  SPACEHAB-04 (CFZF,SEF), SPARTAN-207/IAE, TEAMS(GANE,VTRE,LMTE,PAMS), GBA(12, G-056,G-200), BETSCE, ARF, BRIC

Mission Objectives: 

  NASA's flight of shuttle Endeavour is devoted to opening the
commercial space frontier.  During the flight the crew will perform
microgravity research aboard the commercially owned and operated
SPACEHAB module.  The mission will also deploy and retrieve the 
Spartan-207/IAE (Inflatable Antenna Experiment) satellite and 
will also rendezvous with a test satellite.  A suite of four
technology experiments known as the Technology Experiments for
Advancing Missions in Space (TEAMS) will also fly in the Shuttle's 
payload bay.  

  The SPACEHAB single module will be carrying nearly 3,000 pounds
of experiments and support equipment for 12 commercial space
product development payloads in the areas of biotechnology,
electronic materials, polymers and agriculture as well as several
experiments for other NASA payload organizations.  One of these,
the Commercial Float Zone Facility (CFZF) has been developed through
international collaboration between the U.S., Canada and Germany. 
It will heat various samples of electronic and semiconductor material thru
the float zone technique.  Another facility on SPACEHAB will be the
Space Experiment Facility (SEF) which will grow crystals by vapor
diffusion.

  The Goddard Space Flight Center's (GSFC) Spartan-207 satellite
will be used to deploy and test the Inflatable Antenna Experiment
(IAE) which will lay the groundwork for future technology development
in inflatable space structures.  It will test the performance of a
large inflatable antenna during a ninety-minute mission.  The antenna
structure will then be jettisoned and the SPARTAN-207 spacecraft recovered
at mission end.

  Inside Endeavour's cargo bay the four TEAMS experiments will operate
throughout the mission.  They include the Global Positioning System (GPS) 
Attitude and Navigation Experiment (GANE) which will determine to what
accuracy the GPS system can supply attitude information to a space
vehicle; the Vented Tank Resupply Experiment (VTRE) will test improved
methods for in-space refueling; the Liquid Metal Thermal Experiment (LMTE)
will evaluate the performance of liquid metal heat pipes in microgravity
conditions and the Passive Aerodynamically Stabilized Magnetically Damped
Satellite (PAMS) payload will be a technology demonstration of the principle
of aerodynamic stabilization in the upper atmosphere.  Cameras on the
shuttle will record the PAMS satellite as it is deployed and track its
movements.

  Secondary experiments on the flight will include the 
Brilliant Eyes Ten Kelvin Sorption Cryocooler Experiment (BETSCE), the 
Aquatic Research Facility (ARF) and the Biological Research In a Canister 
(BRIC) experiment.

Launch:  

  Launch Sunday, May 19, 1996 at 6:30:00.066 a.m. EDT  Launch window was
2 hours 30 min. 

  The countdown proceeded very smoothly. The crew suited up, ate
breakfast and was transported to the space shuttle Endeavour on
Launch Pad LC-39B.  By 3:30am EDT 5/19/96 the crew was in the
White Room boarding the shuttle and 6:22am the Countdown clock picked
up at the T-9 minute mark.  Crew visors closed at 6:29am EDT. Liftoff
occured exactly on time.  MECO at 6:40am. EDT.  

  On Friday, 5/17/96 the countdown was proceeding on schedule and 
cryogenic propellant loading operations began shortly before 10:00pm
on Saturday 5/18/96. (Reference KSC Shuttle Status 5/17/1996).

  On Monday, 5/13/96, the access doors were installed on the orbiter's 
aft engine compartment.  The launch countdown began at 4 a.m. Thursday, 
May 16th, 1996 and the crew arrived from the Johnson Space Center 
in Houston at 9 a.m. later that day.(Reference KSC Shuttle Status 5/13/1996).

  On 5/7/96, the Mission Management Team met at the STS-77 
Flight Readiness Review (FRR) and set May 19, 1996 as the official 
launch date.  The original target date of May 16 was not available 
on the Eastern Range schedule.

  On 4/30/96, hypergolic loading was completed. The SpaceHab, TEAMS
and Spartan-207/IAE payload interface verification tests were completed.
(Reference KSC Shuttle Status 5/02/1996).  And on 5/3/96, the 
payload bay doors were closed for flight.
(Reference KSC Shuttle Status 5/06/1996).

  On 4/9/96, rollover of Endeavour occured from OPF Bay 3 to the
VAB.  The Solid Rocket Boosters (SRB's) have been stacked and
mated with external tank.    At 10:00am on 4/16/96, the shuttle 
began it's roll from the VAB to Launch Pad 39-B and arrived at
3:30pm  (Reference KSC Shuttle Status 4/17/1996).

  On 3/25/96, Payload premate testing was complete and the tunnel
adapter was installed and leak checked.  The external tank had
been mated to the solid rocket boosters and close-out operations
were underway.  The Crew Equipment Interface Test (CEIT) and the
landing gear functional test was conducted 3/26/96.
(Reference KSC Shuttle Status 3/26/1996).

  The Space Shuttle Main Engines (SSME's) were installed on Endeavour
in OPF bay 3 (Reference KSC Shuttle Status 3/13/1996).

  The payload bay doors were opened on 1/24/96 for the first time
since Endeavour landed from STS-72. The Japanese satellite retrieved 
during the mission and the OAST-Flyer were removed. Testing continued
on the Flash Evaporator System (Reference KSC Shuttle Status 1/24/1996)
and a decision was made to remove and retest the robotic arm prior
to the next flight (Reference KSC Shuttle Status 1/29/1996)

Orbit:
  Altitude:   153 nm (176 statute miles)
  Inclination:  39 degrees
  Orbits:  161 
  Duration:  10 days, 0 hours, 40 minutes, 10 seconds. 
  Distance:  4.1 million miles

Hardware:
  SRB: BI-080
  SRM:
  ET :  SN-78
  MLP : 
  SSME-1: SN-2037
  SSME-2: SN-2040
  SSME-3: SN-2038

Landing:  
  KSC May 29, 1996 at 7:09:18 a.m. EDT Shuttle Landing Facility Runway 33.  
At 6:00 am EDT, the crew was given a go for the deorbit burn and
the burn was performed at 6:09am EDT.  Main Gear touchdown at
7:09:18 EDT (MET of 10 days, 0 Hours, 39 Min and 18 sec), Nose
Gear touchdown at 7:09:33 (MET of 10 days, 0 hours 39 min 33 sec)
and Wheels Stop at 7:10:10 a.m. EDT (MET of 10 days, 0 hours 40 min 10 sec).
KSC Weather at the time of landing was favorable. (Reference KSC Weather History 05/29/1996 0700).

  There were a total of four landing opportunities for Endeavour on
Wednesday -- two to KSC and two to Edwards Air Force Base. 
The 1st KSC Landing Opportunity on 5/29/96 was selected for a 7:09
a.m. touchdown.  KSC Weather at the time of the deorbit burn was
favorable. (Reference KSC Weather History 05/29/1996 0600).

  The 2nd KSC Landing Opportunity on 5/29/96 would have been at 8:44 a.m. 
EDT, requiring a deorbit engine burn at 7:43 a.m. EST.  The California
landing opportunities would have been at 8:36a.m. EST and 10:11am EST.
(2nd EAFB Landing Opportunity on 5/29/96).

Mission Highlights:

  STS-77 Flight Day 1 Highlights:

 On Sunday, May 19, 1996, 8:30 a.m. CDT, STS-77 MCC Status Report #1
reports: 

  The Shuttle Endeavour blasted off right on time this morning from
the Kennedy Space Center at 5:30 AM Central time following a flawless
countdown and its six astronauts went right to work activating the
Spacehab module systems in the cargo bay laboratory and the ship's
robot arm.

  Commander John Casper, Pilot Curt Brown and crewmates Andy Thomas, 
 Dan Bursch, Mario Runco and Marc Garneau wasted no time moving into their
activities once they reached orbit, deploying the Shuttle's KU-band
radio antenna and beginning the process of turning on a host of
materials and life science experiments in the Spacehab, which is
designed to increase the volume of workspace available to orbiting
Shuttle crews.

  The only glitch during the launch phase this morning occured when a
cooling device for one of Endeavour's three hydraulic power units
froze up, but the water spray boiler is expected to thaw once the
orbiter is maneuvered into its on-orbit experiment orientation and is
not expected to have any impact on the mission.

  The first major activity of the flight will occur Monday morning, when
Runco uses Endeavour's robot arm to grapple and deploy the Spartan
satellite which is housed in the Shuttle's cargo bay. Once it is
deployed, a timing device on Spartan will command a large inflatable
antenna to deploy at the top of a three-legged tripod. The 90 by
50-foot antenna will then be inflated by nitrogen gas in a technology
demonstration of how large inflatable structures can operate in
weightlessness.

 On Sunday, May 19, 1996, 4:30 p.m. CDT, STS-77 MCC Status Report #2
reports:

  Following an on-time launch this morning, the crew of Endeavour set
up a variety of experiments today that will operate for much of the
mission while preparing for tomorrow's work with the first of two
satellites to be deployed during the flight.

  One of the first activities for the crew was to activate the
Spacehab module, making its fourth flight on STS-77 and carrying more
than 3,000 pounds of experiment equipment.  Astronauts Andy Thomas and
Marc Garneau opened the hatch to the Spacehab and entered the module
shortly after the crew was given a go for extended orbital operations.

  Mission Specialist Mario Runco began experiments with the Aquatic
Research Facility, a type of orbital aquarium on Endeavour's lower
deck. The facility, a joint project by the Canadian Space Agency and
NASA, will study the early development in weightlessness of sea
urchins, mussels and starfish. The studies may provide clues to how
humans may develop in weightlessness.

  Other experiments which were activated aboard Endeavour include an
investigation called GANE that uses Global Positioning System
satellites to determine a spacecraft's orientation, an experiment
called BETSCE that tests a new, supercold refrigeration system that
needs no moving parts and could be used on orbiting astronomical
instruments and a Commercial Float Zone Furnace, which will produce
large crystals for use in semiconductors and infrared sensors.

  Mission Specialist Andy Thomas prepared for the deployment of the
Spartan-207 satellite on Monday, as he conducted a thorough checkout
of the Shuttle's robot arm, which Runco will use to grapple and
release the satellite. The Spartan-207 satellite, carrying the
Inflatable Antenna Experiment, will be released at about 6:29 a.m. CDT
Monday and the antenna, which is the size of a tennis court, will be
inflated at about 8:38 a.m. CDT as Endeavour holds position nearby.

  Endeavour is currently in a 176-mile high circular orbit, completing
one revolution of Earth every hour and a half. The crew began an
eight-hour sleep period at 4:30 p.m. CDT and will awaken for Day 2 of
the planned 10-day mission at 12:30 a.m. CDT Monday.

  STS-77 Flight Day 2 Highlights:

 On Monday, May 20, 1996, 7 a.m. CDT, STS-77 MCC Status Report #3
reports:

  The Spartan satellite was released at 6:29 Central time this morning
for its 24 hour free flight away from Endeavour to test new inflatable
antenna technology.

  The Inflatable Antenna Experiment, or IAE, was scheduled to be
inflated shortly after 8:30 this morning.  The inflation procedure
lasts about 5 minutes, bringing the antenna to its full size of 90
feet by 50 feet, or the equivalent size of a tennis court.  After an
hour and a half, the antenna was to be jettisoned from the Spartan.
The satellite will be retrieved tomorrow morning and placed back in
the payload bay for the remainder of the flight.

  Experiment activity continues around the clock aboard the orbiter
and in the Spacehab science module -- even while the crew sleeps.  An
investigation using Global Positioning System satellites to determine
a spacecraft's orientation rather than just location is in progress.
GPS is becoming a more and more useful tool in position location and
attitude which will be beneficial with the International Space Station
in precisely determining its proper position in space.

  Another experiment called BETSCE (pronounced betsy) is testing a
new, supercold refrigeration system that needs no moving parts and
could be used on orbiting astronomical instruments.  The Commercial
Float Zone Furnace operates continuously to produce large crystals for
use in semiconductors and infrared sensors.

  Endeavour is currently in a 176-mile high circular orbit, completing
one revolution of Earth every 90 minutes. The crew was awakened at
12:30 this morning to the "Air Force Song" in honor of Casper, an Air
Force Colonel and Brown, an Air Force Lieutenant Colonel.  The crew
will go to sleep at 4:30 this afternoon.

 On Monday, May 20, 1996, 5 p.m. CDT, STS-77 MCC Status Report #4
reports:

  With the free-flying Spartan spacecraft trailing Endeavour by about
21 nautical miles, and the jettisoned Inflatable Antenna Experiment
leading by a distance of more than 100 nautical miles, the six
astronauts on board Endeavour have begun a planned eight-hour sleep
shift.

  Early this morning, Mission Specialists Mario Runco used the
Shuttle's robot arm to deploy the Spartan and its Inflatable Antenna
Experiment from Endeavour's payload bay.  At 8:38 a.m. Central time,
the antenna structure inflated to its full 92 foot length supporting a
50 foot diameter dish.  Cameras and sensors on the Spartan spacecraft
took precise measurements of the smoothness of the antenna dish
surface.  IAE was jettisoned about 90 minutes later according to plan.

  The antenna continues to move ahead of Endeavour at the rate of 50
to 60 nautical miles with every revolution of the Earth, and at 3:30
p.m. was approximately 85 nautical miles in front of, and below
Endeavour.  Due to IAE's dynamic characteristics -- its large size but
relatively light weight -- an exact orbital lifetime is difficult to
predict, but flight controllers estimate that it should reenter the
Earth's atmosphere within the next 17 to 24 hours.

  The IAE may be visible in the early morning skies over the United
States early Tuesday morning, in those areas where the Shuttle is
predicted to be visible. Viewing opportunities for the antenna will
precede the Shuttle by about one to two minutes.

  Tuesday morning, about 9 a.m. Central time, Endeavour will
rendezvous with the Spartan spacecraft, retrieving it about one hour
later before Marc Garneau uses the robot arm to place it back in the
payload bay for its return to earth.

  Studies with a variety of experiments housed in the Spacehab science
module -- including the Commercial Float Zone Furnace -- will continue
as the crew sleeps. The CFZF operates independently producing large
crystals for use in semiconductors and infrared sensors.

  Endeavour is currently in a 176-mile high circular orbit, completing
one revolution of Earth every 90 minutes. The crew will receive a
wake-up call from Mission Control at 12:30 a.m. Tuesday.

  STS-77 Flight Day 3 Highlights:

 On Tuesday, May 21, 1996, 7 a.m. CDT, STS-77 MCC Status Report #5
reports: 

  Endeavour's astronauts are focusing their attention today on
retrieving the Spartan satellite and returning it to the Shuttle's
payload bay.

  After being awakened at 12:30 a.m. CDT Commander John Casper, Pilot
Curt Brown and Mission Specialist Dan Bursch prepared for the
rendezvous while Mission Specialists Andy Thomas, Mario Runco and Marc
Garneau continued work on the orbiter's middeck and in the Spacehab
module.

  The retrieval operations began shortly after the crew was awakened
by the Fifth Dimension's "Up, Up and Away" in honor of the Inflatable
Antenna Experiment conducted yesterday as part of the Spartan mission.
The IAE was jettisoned later in the morning and is expected to enter
the Earth's atmosphere about 3 p.m. today.

  This morning's rendezvous is the first of four planned during the
mission.  Following a series of jet firings, Endeavour will approach
Spartan to within a distance of about 30 feet, where Garneau will
extend the ship's robot arm to grapple the satellite for its berthing
back on its payload bay platform. After the retrieval of Spartan,
three more rendezvous are scheduled after tomorrow's deployment of a
technology demonstration satellite designed to test an aerodynamically
stabilized method of attitude control.

  Endeavour is currently in a 176-mile high circular orbit, completing
one revolution of Earth every 90 minutes. The crew will go to sleep at
3:30 this afternoon and wake up at 11:30 tonight.

 On Tuesday, May 21, 1996, 4 p.m. CDT, STS-77 MCC Status Report #6
reports:

  Endeavour's third day in space was highlighted by the successful
retrieval of the Spartan- 207 satellite and its complement of data
from Monday's studies with the Inflatable Antenna Experiment.

  As Commander John Casper eased Endeavour within 35 feet of the
Spartan, Canadian astronaut Marc Garneau captured the satellite with
the Shuttle's robot arm at about 9:53 a.m. central time with Endeavour
176 statute miles above New Guinea. Before berthing Spartan back in
Endeavour's payload bay, the astronauts conducted a video and
photographic survey of the satellite attached to the robot arm.

  Inflatable Antenna Experiment investigators will not have an
opportunity to review the data stored on Spartan until after Endeavour
lands next week. The IAE itself remains in orbit and is now predicted
to reenter the Earth's atmosphere and burn up by about 4 a.m.  central
time Wednesday.

  Meanwhile, the crew continued work with the variety of experiments
housed in the Spacehab module, including some troubleshooting of the
Fluid Generic Bioprocessing Apparatus, a soft-drink dispenser designed
to investigate the mixture of fluid and gas in weightlessness. The
troubleshooting was not completed, however, before the crew's day
ended.

  Early Wednesday morning, Mission Specialist Mario Runco will deploy
the PAMS-STU satellite from its canister in Endeavour's payload bay.
This investigation will demonstrate the passive stabilization of a
small satellite using aerodynamic stabilization and magnetic damping,
rather than propellant.  The PAMS-STU satellite will not be retrieved
by Endeavour, but Commander John Casper and Pilot Curt Brown will
maneuver the orbiter to within 2000 feet of the satellite during three
separate stationkeeping exercises to take precise measurements of its
stability and to observe if its behavior matches the predicted models.

  Endeavour is currently in a 176-mile high circular orbit, completing
one revolution of Earth every 90 minutes. The crew will receive a
wake-up call from Mission Control at 11:30 p.m. Tuesday.

  STS-77 Flight Day 4 Highlights:

 On Wednesday, May 22, 1996, 6 a.m. CDT, STS-77 MCC Status Report #7
reports: 

  With the Spartan satellite's mission completed, Endeavour's six
astronauts turned their attention today to the deploy of a small
technology demonstration satellite known as PAMS.

  The Passive Aerodynamically Stabilized Magnetically Damped Satellite
uses aerodynamic stabilization to orient itself properly and
demonstrates a technique that could prolong the lifetime of a
satellite by reducing or eliminating the requirement for attitude
control propellants.

  After Mission Specialist Mario Runco deployed the satellite from a
canister in the rear of Endeavour's payload bay on time at 4:18
a.m. Central time, it drifted away from the orbiter in a rotating,
unstable attitude by design to evaluate how quickly and effectively
the spacecraft could stabilize itself using the aerodynamic
stabilization method rather than with thrusters.

  Commander John Casper and Pilot Curt Brown backed Endeavour away to
a distance of 48,000 feet to begin one of three planned rendezvous
with the satellite to measure its stability using lasers mounted in
the payload bay. The first rendezvous approach was scheduled later
this morning as the crew placed Endeavour at a station-keeping
distance of about 2,000 feet. The second and third rendezvous are
scheduled for Friday and Saturday.

  Meanwhile, the Inflatable Antenna, jettisoned from the Spartan
satellite after its mission Monday, was expected to enter the Earth's
atmosphere today.

  Endeavour is in a 176-mile high circular orbit, completing one
revolution of Earth every 90 minutes. The crew will go to sleep at
3:30 today and awaken at 10:30 tonight.

 On Wednesday, May 22, 1996, 4 p.m. CDT, STS-77 MCC Status Report #8
reports:

  Endeavour's crew spent another day in space devoted to precision
flying as they deployed the second satellite of their mission, moved
nine miles away, and then returned to within a half-mile to study the
satellite's stability.

  Four and one-half hours after releasing and separating from the
Passive Aerodynamically Stabilized Magnetically Damped
Satellite-Satellite Test Unit, or PAMS-STU, early this morning,
Endeavour returned to a position about 2,000 feet from the satellite.
Commander John Casper and Pilot Curt Brown kept Endeavour near
PAMS-STU to allow ground-based researchers to attempt to track the
satellite with instruments mounted in Endeavour's cargo bay.

  PAMS-STU was ejected from its canister in Endeavour's payload bay at
4:18 a.m. central time today.  It was placed in an intentionally
unstable orientation and it is anticipated that it should slowly
reorient itself to a stable attitude. The PAMS-STU technology
demonstration investigates the use of natural, aerodynamic
stabilization to orient a spacecraft properly, a technique that could
prolong the lifetime of future satellites by reducing or eliminating
the requirement for attitude control propellants.

  During the two hours Endeavour held position this morning,
investigators noted that the satellite had not yet stabilized and they
did not obtain a strong lock on the satellite using the laser-based
tracking instruments aboard the shuttle. However, two more such close
encounters with the satellite are planned later in the flight to check
its progress.  Those stationkeeping exercises are expected to last up
to six and one-half hours each.

  The astronauts have begun an eight-hour sleep period and will awaken
to begin Flight Day 5 at 11:30 p.m. central time today.  Flight Day 5
will be dedicated to continued scientific investigations in the
Spacehab module.

  All of Endeavour's systems continue to perform well as the orbiter
circles the Earth every 90 minutes at an altitude of 175 statute
miles.

  STS-77 Flight Day 5 Highlights:

 On Thursday, May 23, 1996, 7 a.m. CDT, STS-77 MCC Status Report #9
reports: 

  The work aboard the Space Shuttle Endeavour has switched from
rendezvous and proximity operations with satellites to science
gathering aboard an orbiting laboratory.

  The six astronauts spent the first half of their workday assisting
payload controllers with investigations into materials processing of
samples and the growth of crystals while documenting the progress of
starfish and mussel development in a spaceborne aquarium in the
Spacehab module in the Shuttle's cargo bay.

  The crew was awakened at 11:30 PM Central time last night with a
children's song from Mission Control called "Milky Way". The crew then
moved off in different directions to support work with many of the
experiments that make up the fourth mission of the Spacehab
pressurized module.

  Endeavour is about 64 miles away from the Passive Aerodynamically
Stabilized Magnetically Damped Satellite-Satellite Test Unit, or
PAMS-STU, which was deployed from a canister in the payload bay
yesterday.  A small engine firing aboard Endeavour is planned later
this morning to begin the slow re-rendezvous with the satellite
scheduled for Saturday.

  This technology demonstration experiment investigates the use of
natural, aerodynamic stabilization to orient a spacecraft properly, a
technique that could prolong the lifetime of future satellites by
reducing or eliminating the requirement for attitude control
propellants.

  During the first proximity operations of Endeavour to the satellite,
a strong lock on the satellite using the laser-based tracking
instruments aboard the shuttle was not obtained.  However, two more
close rendezvous operations with the satellite are planned Saturday
and Sunday to check its progress.  Those stationkeeping exercises are
expected to last up to six and a half hours each.

  The astronauts also completed an in-flight maintenance procedure to
improve the flow of beverages in a dispenser aboard Endeavour designed
to test the capability of soft drinks to stay cold and carbonated in
weightlessness.

  The astronauts will go to bed at 2:30 this afternoon and will wake
up at 10:30 tonight.  Endeavour continue to provide a stable platform
for the science investigations going on around the clock, even while
the crew sleeps.  The orbiter's current altitude is 175 statute miles
with an orbital period of 90 minutes.

 On Thursday, May 23, 1996, 4 p.m. CDT, STS-77 MCC Status Report #10
reports: 

  Endeavour's crew members spent their fifth day in space tending to a
host of experiments today, ranging from biological studies of sea
creatures in weightlessness to experiments in crystal growth and
materials processing.

  Commander John Casper, Pilot Curt Brown and Mission Specialists Dan
Bursch and Andy Thomas took a brief break from their work today to
answer questions from CNN, and Canadian astronaut Marc Garneau, along
with Bursch, also spoke with Canadian networks CBC and RDI. As the
attention of the crew turned to the laboratory work inside the
spacecraft, Endeavour maintained its distance from the PAMS-STU
satellite released yesterday. Casper fired the shuttle's jets today in
one of a series of periodic engine firings which, during the next two
days, will keep Endeavour poised for a return to the PAMS- STU
Saturday for continued studies of the satellite's stability.

  Also today, Bursch and Garneau repaired the Fluid Generic
Bioprocessing Apparatus, an orbital soft drink dispenser, which had a
cooling problem. The dispenser was then tested by the crew and
currently is working well in filling drink containers.

  The six astronauts will be awakened at 10:30 p.m. central time today
to begin their sixth flight day on orbit, another day devoted to
scientific and technical investigations in the Spacehab module.  The
crew also will enjoy a few hours off tomorrow, a standard policy
during longer shuttle missions, to ensure the crew remains well
rested.

  Endeavour continues to circle the Earth every 90 minutes at an
altitude of 175 miles with all systems on board performing well.

  STS-77 Flight Day 6 Highlights:

 On Friday, May 24, 1996, 6 a.m. CDT, STS-77 MCC Status Report #11
reports: 

  Halfway through the STS-77 mission, the six Endeavour astronauts
spent some time relaxing, then went back to working in the Spacehab
module and preparing to revisit a small cylindrical satellite they
deployed several days ago.

  While Commander John Casper and Pilot Curt Brown monitored
Endeavour's systems, Mission Specialist Mario Runco tested an attitude
determination system using the GPS attitude and navigation experiment
called GANE.  The remaining crew members -- Mission Specialists Andy
Thomas, Dan Bursch and Marc Garneau -- monitored the health of
experiments ongoing in the Spacehab and on the middeck of the orbiter.

  Thomas monitored the Space Experiment Facility (SEF), Garneau worked
with the Commercial Float Zone Furnace (CFZF), changing samples and
videotapes, and Bursch taste tested soda in the Fluids Generic
Bioprocessing Apparatus (FGBA), which was repaired during an inflight
maintenance procedure yesterday.

  The crew also conducted a health check of the Aquatic Research
Facility (ARF) which contains starfish, mussels and sea urchins.
Three separate investigations are being conducted to study embryonic
development in space, adult tissue structure and the ability to orient
to the microgravity environment of space.  The investigations are
designed to help researchers understand and improve models of human
adaptation to space and the factors that may disrupt that adaptation.

  The crew will perform a small engine firing later today to refine
the distance between Endeavour and the small PAMS-STU satellite in
preparation for tomorrow's planned second rendezvous with the
spacecraft. The astronauts answered questions from the rendezvous team
in Mission Control to better understand their ability to see the
satellite and verify its orientation under different lighting
conditions.  The two spacecraft are currently about 60 miles apart.

  The crew will go to sleep at 1:30 this afternoon and wakeup at 9:30
tonight.  Endeavour's 11th mission begins the second half of the
flight at a stable altitude of 175 miles with an orbital period of 90
minutes.

 On Friday, May 24, 1996, 5 p.m. CDT, STS-77 MCC Status Report #12
reports:

  Endeavour's astronauts enjoyed a few hours off today following a
busy pace of scientific investigations and satellite deployments
during the first half of their mission.

  Crewmembers today tended to several investigations in the Spacehab
module and on Endeavour's middeck, and began preparations for Saturday
morning's rendezvous with the PAMS-STU satellite.  The small satellite
was deployed from Endeavour's payload bay Wednesday to begin a study
into the use of natural, aerodynamic stabilization to maintain a
spacecraft's attitude on orbit.

  Saturday morning's rendezvous will be the second visit paid by
Endeavour to the satellite since its deployment.  Commander John
Casper and Pilot Curt Brown will again pull to within 2,000 feet
behind PAMS-STU and remain there for approximately six and one-half
hours.  During that stationkeeping exercise, a device in Endeavour's
cargo bay will measure the satellite's stability and orientation by
reflecting light on the satellite.  The images returned by those
reflectors will be recorded by the AMS for subsequent analysis to
determine the satellite's stability on orbit.

  Preparations for the rendezvous will begin shortly after the crew
awakens at 9:30 p.m.  Central time today.  Casper and Brown will
perform a series of engine firings to put Endeavour on a course to
intercept PAMS-STU, and should arrive at the 2,000-foot point about 3
a.m. central time Saturday.

  STS-77 Flight Day 7 Highlights:

 On Saturday, May 25, 1996, 6:30 a.m. CDT, STS-77 MCC Status Report #13
reports: 

  Endeavour returned to the small, cylindrical PAMS-STU satellite
today and began eight hours of station-keeping about 1,800 feet away
that will conclude about 11 a.m.

  The second rendezvous with the Passive Aerodynamically Stabilized
Magnetically Damped Satellite (PAMS) began shortly after the crew was
awakened to the song "Down Under" performed by Men At Work, in honor
of Australian-born Mission Specialist Andy Thomas.

  Commander John Casper and Pilot Curt Brown performed a series of
thruster firings over the course of several hours that allowed
Endeavour to close in on the 2 foot by 3 foot satellite.  The PAMS
Satellite Test Unit was deployed from a canister in the rear of the
payload bay Wednesday to begin a study into the use of aerodynamic
stabilization to maintain a spacecraft's attitude on orbit.  The
rendezvous took place as other crewmembers monitored science
experiments ongoing in the Spacehab module and on the middeck of the
orbiter.

  Casper and Brown pulled to within less than 2,000 feet behind
PAMS-STU on time at 3 a.m. today where the astronauts began to take
attitude measurements of the satellite's stability by reflecting laser
light on the satellite.  The images returned by reflectors on the
PAMS-STU satellite are being recorded by the Attitude Measurement
System in Endeavour's cargo bay for analysis.

  Today's rendezvous is the second of three planned visits to the
satellite since its deployment, and the third of a record four planned
during the mission.  The final rendezvous with the PAMS-STU, planned
for tomorrow, could be rescheduled for Monday depending on the results
of this morning's exercise.

  Just as Endeavour approached the satellite, a commanding problem was
seen with the Space Experiment Facility in the Spacehab module and
Thomas began troubleshooting procedures called up from the Payload
Operations Control Center. A few hours later, payload officials said
the device had failed. SEF was one of several materials processing and
crystal growth experiments that make up the flight's science
investigations.

  Endeavour continues to provide a stable platform for the scientific
investigations being conducted on board.  The six-astronaut crew will
go to sleep at 1:30 this afternoon and will be awakened at 9:30
tonight.

 On Saturday, May 25, 1996, 6 p.m. CDT, STS-77 MCC Status Report #14
reports:

  Endeavour returned to the small, cylindrical PAMS-STU satellite this
morning holding position about 1,700 feet behind it for more than six
hours as scientists studied the experimental craft's stability and
orientation.

  Through video of the satellite taken by Endeavour's crew and
information gleaned from the shuttle's radar system, experimenters
reported the satellite was stabilizing using natural aerodynamic
forces, although stabilization appeared to occur slower than
anticipated.  PAMS-STU studies the use of weighting and the Earth's
magnetic field to stabilize a small satellite in orbit instead of
using costly and complex steering jets.

  A third and final rendezvous with PAMS-STU for further observations is
scheduled for Monday, one day later than originally
planned. Scientists requested the final encounter be postponed 24
hours to allow time to evaluate the Attitude Measurement Systems, a
laser- based system designed to provide highly accurate readings of
PAMS-STU behavior.

  Although scientists reported good results today from the PAMS-STU
visual and radar observations, they experienced some difficulty
tracking the satellite with the AMS. The system did appear to track
the satellite for extended periods several times this morning, but
investigators want to be sure the laser system is tracking the
appropriate reflector targets on the satellite. The AMS should provide
data on the PAMS-STU stability accurate to one-tenth of one degree.

  The crew began a sleep period at 1:30 p.m. Central time and will
awaken for Day 8 of STS-77 at 9:30 p.m. With the final PAMS-STU
rendezvous rescheduled to Monday, the crew will perform activities on
Sunday that had originally been planned for Monday.

  In addition to a slate of experiment work in the Spacehab module,
Sunday's schedule includes a crew news conference at 6:40 a.m. Central
time.  The astronauts will discuss their mission with media in the
United States and Canada.

  Endeavour, in a 177 by 172 mile-high orbit, is in excellent mechanical
condition with no system problems being tracked by flight controllers.

  STS-77 Flight Day 8 Highlights:

 On Sunday, May 26, 1996, 8 a.m. CDT, STS-77 MCC Status Report #15
reports: 

  Endeavour's crew spent the first half of its eighth day on orbit
working with experiments and helping payload controllers troubleshoot
unexpected readings by equipment designed to acquire data on the
PAMS-STU satellite's ability to stabilize itself.

  Commander John Casper and Pilot Curt Brown watched over orbiter
systems and helped Bursch and payload controllers on the ground
investigate potential causes of the failure of the Attitude
Measurement System to effectively lock on to reflective targets
mounted on the PAMS-STU satellite. Even though video of the satellite
and information from the shuttle's radar system showed the satellite
in a stable attitude using aerodynamic stabilization rather than
propellant for control, the AMS continued to lock on to an unknown
target that may be an undetermined structure in the payload bay.

  Troubleshooting is continuing and experts on the ground are
discussing what course of action to take leading up to tomorrow's
third and final planned rendezvous with the small satellite.
Scientists asked to postpone the final encounter by 24 hours to allow
time to evaluate the laser-based measuring system designed to record
data accurate to one-tenth of one degree.

  The astronauts took time out from their schedule to discuss the
progress of the mission with reporters. Casper said the flight has
been highly successful so far, having accomplished all of the goals
set out before launch.

  Overnight, Mission Specialists Dan Bursch and Andy Thomas described
protein crystal growth and plant growth experiments being conducted
throughout the flight in the Spacehab module.  Meanwhile, Mario Runco
tested soft drink samples in the Fluids Generic Bioprocessing
Apparatus and Marc Garneau checked sample growth in the Commercial
Float Zone Furnace.

 On Sunday, May 26, 1996, 4 p.m. CDT, STS-77 MCC Status Report #16
reports:

  Endeavour's crew spent its eighth day in orbit working with a host
of on-board experiments and performing a quick repair on a Spacehab
module cooling system.

  Mission Specialists Andy Thomas and Dan Bursch fixed a faulty cooling
system in the Spacehab module today by switching a valve in the
cooling water loop to a backup motor. For the past day, the valve had
not been opening and closing in response to the settings of a
thermostat in the module, set to regulate the temperature at about 76
degrees Fahrenheit. Temperatures in the module had cooled off to about
70 degrees Fahrenheit during the day the valve was stuck open.  It is
now operating normally.

  Crew members also spent a half-hour answering questions from
U.S. and Canadian media during their in-flight news conference.

  In preparation for Monday morning's planned rendezvous with the
PAMS-STU satellite, Commander John Casper fired Endeavour's
steering jets to put the shuttle on a course closing in toward
PAMS-STU. Endeavour had been moving away from the satellite for about
24 hours, reaching a maximum distance of about 115 miles before that
engine firing. The two spacecraft currently are about 60 nautical
miles apart, with Endeavour closing in on PAMS-STU at the rate of 2
nautical miles per orbit.

  STS-77 Flight Day 9 Highlights:

 On Monday, May 27, 1996, 7 a.m. CDT, STS-77 MCC Status Report #17
reports: 

  The third rendezvous with the small aerodynamically stabilized
satellite went by the book this morning as Commander John Casper and
Pilot Curt Brown guided Endeavour to just under 2,000 feet from the
cylindrical shaped PAMS-STU satellite.

  While the orbiter's payload bay was pointed carefully toward the
satellite, payload controllers at NASA's Goddard Space Flight Center
sent commands to an on- board Attitude Measurement System (AMS) to try
to calculate the satellite's attitude to within a tenth of a degree of
accuracy.

  The crew was given permission to move within 1,650 feet and
controllers verified the laser was hitting the reflectors on the
satellite, confirming that the Shuttle was pointed correctly.

  The mechanism which swivels the AMS to the proper position was slowly
moved through various positions to lock on to the satellite to gather
attitude data.  The PAMS-STU (Passive Aerodynamically Stabilized
Magnetically Damped Satellite - -Satellite Test Unit) was deployed
from a small canister in Endeavour's payload bay Wednesday in an
unstable, slightly tumbling attitude to observe how or whether it
could stabilize itself without using satellite lifetime-limiting
propellants.

  The technology demonstration experiment has, according to engineers,
proven the concept of propellent-free satellite stabilization based on
comments from the crew during three separate rendezvous.

Endeavour's close encounter with the PAMS-STU is scheduled to last
until about 9 this morning before a final separation maneuver is
conducted. The satellite is expected to reenter the Earth's
atmosphere and burn up in about a month.

Casper was scheduled to take time out during the final phase of the
rendezvous to talk to fellow astronaut Shannon Lucid and her two
cosmonaut crewmates aboard the Russian Space Station Mir at about 8:25
this morning.  The conversation was scheduled as the two vehicles
passed within about 900 miles of one another over New Guinea and the
Philippines.

Late today and tomorrow the crew will wrap up science investigations
and begin shutting down experiments and packing up the orbiter for
Wednesday's planned return to Earth.  Landing is currently
scheduled for 6:12 a.m. Central time at the Kennedy Space Center in
Florida.

  Endeavour's eleventh mission is in the homestretch with all systems
in excellent shape.  The crew will go to bed at 1:30 this afternoon
and will be awakened at 9:30 tonight.

 On Monday, May 27, 1996, 5 p.m. CDT, STS-77 MCC Status Report #18
reports:

  Endeavour's third and final encounter with a satellite deployed from
the shuttle five days ago was highlighted by almost eight hours of
formation flying, with science investigators reporting they obtained
the best measurements yet on the stability of the PAMS-STU satellite.

  For seven hours and 45 minutes, Pilot Curt Brown held Endeavour in
position less than 1,600 feet behind PAMS-STU, as video cameras and
other instruments documented the satellite's behavior.

  The Attitude Measurement System (AMS), a laser-based instrument in
Endeavour's payload bay, consistently locked on to the satellite today
and attained highly accurate readings. During two previous encounters,
the AMS experienced some difficulty accurately tracking the satellite.
With AMS performing so well, the stationkeeping activities were
extended about an hour and 10 minutes to allow scientists to gather as
much information as possible.

  PAMS-STU appeared to be very stable, demonstrating the concept of
using aerodynamic forces and the Earth's magnetic field to naturally
control a small satellite in orbit, without a need for thrusters.

  Based on the satellite's stability, flight controllers revised their
estimate of its orbital lifetime, predicting that it could remain in
orbit until January 1997.  Initial estimates predicted an orbital
lifetime of several weeks.  PAMS-STU is expected to burn up when it
reenters the Earth's atmosphere.

  As Endeavour held position with the satellite today, Commander John
Casper spoke briefly with astronaut Shannon Lucid, marking her 65th
day on board Russia's Mir space station.

  The six-member Endeavour crew will awaken at 9:30 p.m. central time
today to begin what should be its final full day on orbit.  Flight Day
10 will see the astronauts perform routine activities for the day
before landing.  Casper, Brown and Mission Specialist Dan Bursch will
conduct a checkout of systems to ensure the orbiter is in top shape
for its return to Earth early Wednesday morning.  The astronauts also
will begin to deactivate some of the experiments housed in the
Spacehab module, and stow some of the equipment they have used over
the past nine days on orbit.

  STS-77 Flight Day 10 Highlights:

 On Tuesday, May 28, 1996, 6 a.m. CDT, STS-77 MCC Status Report #19
reports: 

  Endeavour's flight control system was checked earlier today and
verified in good working order to support a return to Earth tomorrow
at the Kennedy Space Center in Florida or at the Edwards Air Force
Base facility in California, weather permitting.

  Shortly after wakeup late last night to the Rolling Stones "Start Me
Up", the six astronauts began cleaning up the orbiter for the trip
home and checked the movable control surfaces on the wings and tail to
verify they are working properly for the atmospheric portion of the
entry.  Consoles in Mission Control were shared through the night by
entry flight controllers preparing messages for the crew related to
landing and also to review weather conditions forecast for landing.

  Weather conditions are expected to be favorable for landing tomorrow
in Florida, but a cold front is expected to move into Florida before
Thursday's landing opportunities.  Based on that forecast, and a
deteriorating forecast for California, both sites will be supporting
landing tomorrow.

  Two landing opportunities are available at each location Wednesday.
The Florida landing opportunities are at 6:09 a.m. and 7:44
a.m. Central.  The California landing times are 7:36 a.m. and 9:11
a.m. Central.

  The entry team will arrive at Mission Control at 11 p.m. to watch
over Endeavour and its crew through the final hours of the STS-77
mission.  The crew will wake up at 9:30 this evening to prepare for
the end of mission.

 On Tuesday, May 28, 1996, 5 a.m. CDT, STS-77 MCC Status Report #20
reports:
 
  Endeavour's crew Tuesday spent its final full day in orbit preparing
for a Wednesday morning return to Earth.
 
  The astronauts performed a routine check of the shuttle's flight
control surfaces and reaction control system jets, wrapped up work
with a number of scientific investigations, and began securing the
cabin for the trip back to Earth.  Most experiments aboard the shuttle
have been completed and stowed away, although a few will operate
throughout the night and be deactivated once the crew wakes.
 
  Crew members Andy Thomas, a native of Australia, and Marc Garneau, a
Canadian, each received special greetings today as STS-77 neared its
end. South Australia Premier Dean Brown called Thomas with
congratulations early this morning as the shuttle passed above Brown's
office in Adelaide, Australia, Thomas' hometown. Later, Canadian Prime
Minister Jean Chretien called Garneau to congratulate him on the
mission and the joint Canadian Space Agency and NASA experiments that
were conducted.
 
  The crew will awaken at 9:30 p.m. and prepare for a Wednesday
morning return to the Kennedy Space Center. Weather conditions in
Florida are expected to be acceptable for landing, with only a
possibility of rain. If weather precludes a landing in Florida, flight
controllers have the option of returning Endeavour to Edwards Air
Force Base in California.  The Edwards site is available to support a
Wednesday landing, if required.
 
  There are a total of four landing opportunities for Endeavour on
Wednesday -- two to KSC and two to Edwards Air Force Base.  The first
landing opportunity would call for firing Endeavour's braking rockets
at 5:09 a.m. Central time, with a landing at 6:09 a.m.  on KSC Runway
33.  The second KSC opportunity has a deorbit engine firing at 6:43
a.m.  Central time, followed by a landing at 7:44 a.m.
 
  There are also two opportunities for Endeavour to land in
California, where the weather is expected to be acceptable to support
landing.  The first opportunity calls for the deorbit burn conducted
at 6:35 a.m. Central time with a landing at 7:36 a.m. on Runway 22.
The second opportunity would have a deorbit burn at 8:10 a.m. Central
time with landing to follow at 9:11 a.m.
 
  As Endeavour returns to Earth, it will conclude a voyage of 4.1
million miles, having performed a record four rendezvous during its 10
days on orbit. Endeavour rendezvoused with and retrieved the Spartan
207 satellite, and visited the PAMS-STU satellite three times,
spending a total of 21 hours of precise formation flying.

  STS-77 Flight Day 11 Highlights:

 On Wednesday, May 29, 1996, 6:30 a.m. CDT, STS-77 MCC Status Report #21
reports: 

  The Shuttle Endeavour glided home this morning to a smooth landing
at the Kennedy Space Center to wrap up a 10-day, 4.1 million mile
mission devoted to technology research.

  Commander John Casper and Pilot Curt Brown guided Endeavour to a
touchdown on Runway 33 at 6:09 AM Central time, wrapping up the fourth
Shuttle mission of the year in which the astronauts completed four
rendezvous' with a Spartan satellite and an aerodynamically stabilized
satellite called PAMS-STU, designed to test new ways to keep a
satellite in the correct orientation without the use of propellents.

  Casper and Brown fired Endeavour's braking rockets at 5:09 AM
Central time to enable the Shuttle to drop out of orbit for its
hour-long slide back to Earth. Endeavour streaked across the Pacific,
the San Francisco Bay Area, the Rocky Mountains and the Gulf Coast
before crossing over into Florida to align itself with KSC's Shuttle
Landing Facility.

  This is Endeavour's last flight until December 1997, when it will be
launched again on the STS-88 mission, the first launch of
U.S. hardware for the assembly of the International Space
Station. Endeavour will be ferried to Palmdale, California in August
for eight months of major modifications in preparation for Station
assembly missions.

  Endeavour's astronauts will return to Ellington Field at about 4:30
this afternoon following medical exams in Florida and reunions with
their families.

<end of mission>

Mission Name: STS-78 (78)
  Columbia (20)         
  Pad 39-B (37)
  78th Shuttle Mission
  20th Flight OV-102
  KSC Landing (31)
  Longest Mission to date

 NOTE: Click Here for Countdown Homepage

Crew:
  Terence T. Henricks (4), Commander 
  Kevin R. Kregel (2), Pilot
  Susan J. Helms (3),  Flight Engineer
  Richard M. Linnehan, DVM (1), Mission Specialist
  Charles E. Brady, Jr., MD (1), Mission Specialist
  Jean-Jacques Favier, PhD (1) (CNES), Payload Specialist
  Robert Brent Thirsk, MD (1) (CSA), Payload Specialist

  Pedro Duque (0) (ESA), Alternate Payload Specialist
  Luca Urbani, MD (0) (ASI), Alternate Payload Specialist

Milestones:
     OPF -- 3/9/96  (Reference KSC Shuttle Status 3/09/1996)  
     CEIT - 5/10/96 (Reference KSC Shuttle Status 5/13/1996)  
     VAB -- 5/20/96 (Reference KSC Shuttle Status 5/21/1996)  
     PAD -- 5/30/96 (Reference KSC Shuttle Status 5/30/1996)
     TCDT - 6/04/96 (Reference KSC Shuttle Status 6/04/1996)
     FRR -- 6/06/96 (Reference KSC Shuttle Status 6/06/1996)

  (Reference KSC Shuttle Status May 1996)
  (Reference KSC Shuttle Status Jun 1996)
  (Reference KSC Shuttle Status Jul 1996)

Payload:
  SPACELAB-LMS, SAMS-D, OARE, BDPU(TMIBD,SIE), SAREX-II

Mission Objectives:
    The scheduled 15-day, 21-hour STS-78 Life and Microgravity Spacelab 
(LMS) mission will help set the stage for the International
Space Station by studying the effects of long-duration space flight on
human physiology and conducting the type of experiments that would fly
on the orbital platform. Columbia will climb to a 173-statute-mile
(278-kilometer)-high orbit with a 39-degree inclination to the Earth's
equator to allow the seven-member flight crew to maintain the same
sleep/wake rhythms they are accustomed to on Earth and to reduce
vibrational and directional forces that could affect on-board
microgravity experiments.

     Once in orbit, the crew will enter the 40-foot (13-meter)
pressurized Spacelab module to begin the 22 LMS life science and
microgravity experiments in the laboratory and in lockers in the
middeck area of the orbiter's crew cabin. Thirteen of the life
sciences experiments will be devoted to the study of the effects of
microgravity on human physiology, while six microgravity experiments
will be conducted to produce metallic alloys and protein crystals and
study the behavior of fluids and materials processing in the
near-weightless environment of space.

       The mission's experiments will build on previous Shuttle spacelab
 flights dedicated to life sciences and microgravity investigations
 (Spacelab Life Sciences 1 and 2 -- STS-40 and STS-58, and International
 Microgravity Laboratory 1 and 2 -- STS-42 and STS-65).

Launch:  
  Launch June 20, 1996 10:49:00.0075 a.m. EDT.  Launch window was
2 hours 30 min.  The STS-78 launch countdown was conducted in Firing Room 3
of the Launch Control Complex (LCC) and it included 35 hours 49 minutes of
built in holds. (For hold times, Reference KSC Shuttle Status 6/18/1996). 

  On 6/20/96, the payload crew was woken up at 5:39am EDT and the flight
crew at 5:54am EDT.  The crew had breakfast in the Operations and Checkout
Building at 6:25am EDT.  At 7:29am EDT, the  countdown clock came out of
a scheduled two hour hold and was at T-3 hours and counting.  At 7:31am 
EDT, the crew departed the O&C building on their way to Launch Pad 39A.
The crew entered Columbia and the hatch was closed out by 9:29am EDT. At
10:19am EDT the countdown clock picked up the T-20 minutes and counting.

  On 6/19/96, workers completed closeout of the aft engine compartment
and the Master Events Controller (MEC) #1 was retested and no problems
were found relating to its critical control functions.  The MEC has been
cleared for flight.  All late access stowage of experiments in the Spacelab
module and middeck were completed.  The RSS was retracted around 10:30 pm.
(Reference KSC Shuttle Status 6/19/1996). 

  On 6/18/96, the mission management team decided to have the aft main
engine compartment reopened and X-ray the Power Drive Units (PDU) for
the orbiter's external tank doors.  The units were suspected of having 
possible loose screws in the PDU terminal circuitry boards because of
inspections on the orbiter Atlantis PDU's.  After the X-rays were
developed, it was verified that all suspect screws are secure and properly
installed and the aft compartment was closed again for flight.  Cryogenic
reactant loading into the power reactant storage and distribution system 
and the extended duration orbiter (EDO) pallet was completed and late access
stowage of experiments into the Life and Microgravity Spacelab (SPACELAB-LMS) 
payload will begin on 6/19/96.  KSC area weather forcases indicate a 60
percent probability of good weather on launch day. (Reference KSC Shuttle Status 6/18/1996).  (Reference KSC Weather History 06/18/1996 2000).  Another
issue has arisen concerning the No. 1 Master Events Controller (MEC).  During
routine testing, engineers noticed incorrect BITE (Built In Test Equipment) 
indications from the MEC. Further analysis revealed the software errors 
were not critical to this mission, but managers want to insure the errors 
are not masking other potential problems that might come to light later 
in the countdown.  There are two MECs in the orbiter's aft engine 
compartment.  They process signals to arm and safe pyrotechnics and command 
and fire pyrotechnics during SRB / external tank separation and orbiter / 
external tank separation.

  On 6/17/96, the Countdown began at the T-43 hour mark at 4:00am EST.
A countdown status briefing was held 9:30am EST and crew arrived
at KSC SLF at 3:30pm. (Reference KSC Shuttle Status 6/17/1996). 

  On 6/3/96, Columbia's crew arrived for the Terminal Countdown
Demonstration Test.  The TCDT is a countdown rehearsal for the crew
and launch team at KSC and is conducted prior to each flight.  The
test ends on 6/4/96 with a simulated main engine shutdown at the pad.
(Reference KSC Shuttle Status 6/03/1996). 

  On 5/29/96, the Shuttle Columbia began moving out of the Vehicle
Assembly Building to Pad 39B at around 11:50pm.  The shuttle arrived
at the pad about 5 hours later. (Reference KSC Shuttle Status 5/29/1996). 
  
  On 4/18/96, in OPF Bay 2, the installation of the three 
Space Shuttle Main Engines (SSME's) was completed as well
as the removal and replacement of the No. 3 TACAN unit used
in landing navigation.  In the O&C Building, closeouts of
the Spacelab Life Sciences LMS Payload were completed.
(Reference KSC Shuttle Status 4/18/1996).  The LMS payload moved 
to the Orbiter Processing Facility and was installed in Columbia. 
(Reference KSC Shuttle Status 4/29/1996) and the tunnel adapter was 
installed 4/30/96. (Reference KSC Shuttle Status 5/01/1996).

  On 3/27/96, in Orbiter Processing Facility (OPF) Bay 2, the drag chute
was installed on orbiter Columbia and test were started on the
Orbital Maneuvering System (OMS).  The Space Shuttle Main Engines (SSME's)
are scheduled to be installed April 15. (Reference KSC Shuttle Status 3/27/1996).  The nose landing gear wheel and tires were installed on 3/29/96 and
 the payload bay was prepared for the Spacelab Life and Microgravity
Science Laboratory.  Also Tacan No. 1 did not pass functional testing and
was removed. (Reference KSC Shuttle Status 3/29/1996).  In the OPF, 
Columbia's Windows No. 3 and 4 were polished and in the VAB, stacking
of the left Solid Rocket Booster (SRB) on the Mobile Launcher Platform (MLP)
was underway.  A Crew Equipment Interface Test (CEIT) was also being
conducted on Spacelab LMS experiments in the Operations and Checkout (O&C)
building. (Reference KSC Shuttle Status 4/02/1996).  On 4/5/96, leak
and functional checks of the LOX side of the MPS was completed and work
was done to remove one of the orbiter's S-Band transponders which did not
pass testing. (Reference KSC Shuttle Status 4/05/1996)

Orbit:
  Altitude:    173 statute miles
  Inclination:   39 degrees
  Orbits:  271
  Duration: 16 days, 21  hours, 48 minutes,  30 seconds.
  Distance:  7 million miles

Hardware:
  SRB: BI-081
  SRM:
  ET :  SN-79
  MLP : 
  SSME-1: SN-2041
  SSME-2: SN-2039
  SSME-3: SN-2036

Landing:  
  KSC July 7, 1996 8:37.30 a.m. EDT.  Runway 33.  At 7:25 a.m. EDT 
Columbia was given the go for a deorbit burn on the first KSC Landing 
opportunity.   The burn occured on orbit 271 at 7:37 a.m. EDT and the
landing at KSC completed 272 revolutions of the planet. KSC weather at 
the time of landing was acceptable. Cloud ceilings were at 13,000 
and 21,000 ft. (Reference KSC Weather History 07/07/1996 0800).
Main Gear Touchdown at Mission Elapsed Time (MET) of 16 days 21 hours 47 min
45 sec. Nose Gear Touchdown at MET 16days 21hours 47min 57sec and Wheels 
stop at 16days 21hours 48min 30sec.

  Two landing opportunities were available Sunday, July 7. The first
at 8:37 a.m. EDT and the second at 10:11 a.m. EDT. No landing support 
was scheduled for Edwards Air Force Base (EAFB) California on July 7th 
and in the event of bad weather at KSC, Columbia would have remained 
in orbit an additional day.  On Monday, two landing opportunities were 
available at KSC and two at Edwards. KSC Monday landing opportunities 
were 8:29am EDT and 10:03am EDT.  EAFB landing opportunities for 
Monday were at 9:55am EDT and 11:29am EDT. (Reference KSC Press Release 84-96)

Mission Highlights:

  STS-78 Flight Day 1 Highlights:

 On Thursday, June 20, 1996, 12:00 p.m. CDT, STS-78 MCC Status Report #1
reports: 

  The Space Shuttle Columbia blasted off from Florida's Kennedy Space
Center on time at 9:49 a.m. CDT today on a 16-day medical research
mission that, if extended to 17 days as planned, would become the
longest shuttle mission in history.

  The seven member crew of U.S., French and Canadian astronauts will
conduct 41 major experiments on how human beings and other living
organisms along with various materials change in a weightless
environment.

  Crew members opened the shuttle's payload bay doors about 11:15
a.m. CDT, signaling the beginning of orbital operations and giving the
go-ahead to activate the pressurized Spacelab module which is housed
in Columbia's cargo bay.

  With all systems aboard Columbia performing well, the orbiter
continues to circle the Earth every 90 minutes at an altitude of 176
statute.

 On Thursday, June 20, 1996, 5:00 p.m. CDT, STS-78 MCC Status Report #2
reports:

  Orbiting more than 170 miles over the surface of the Earth,
Columbia's astronauts successfully activated the Spacelab module
housing more than 40 life science and microgravity experiments in the
Shuttle's cargo bay.

  The experiments focus on the physiological changes that take place
in the human body during spaceflight and also on utilizing the unique
microgravity environment to study materials processing techniques.
For the next 16 days, the seven-member crew will devote their time to
these investigations.

  Commander Tom Henricks shared a unique view of Columbia's climb to
orbit with flight controllers today, replaying images from a small
camera that was mounted on the flight deck.  The video followed
Columbia's flight from just before main engine start through main
engine cutoff, showing the force of main engine and solid rocket
booster ignition as experienced by the astronauts.

  Late this afternoon, flight controllers performed a dump of the
Backup Flight Software that experienced intermittent transients during
Columbia's launch this morning. With the dump complete, the flight
control team will assess and evaluate the data.  The error seen on the
BFS this morning will not affect orbiter operations or mission
duration.
	
  With all systems aboard Columbia and in the Spacelab performing
well, work with the life and microgravity science payloads is underway
as the orbiter circles the Earth very 90 minutes.

 On Thursday, June 20, 1996, 6:30 p.m. CST, STS-78 Payload Status Report #01
reports: (MET 0/09:00)

  The Life and Microgravity Spacelab mission, laying the foundation
for future long-term space exploration, is under way after a picture-
perfect launch of Space Shuttle Columbia at 9:49 a.m. CDT today.

  After achieving an intended altitude of 173 statute miles above
Earth, where Columbia will orbit for the next 16 days, the
seven-member flight crew began work immediately.

  In fact, they began ahead of schedule: Approximately an hour before
scheduled, the crew opened and set up their Spacelab laboratory -- the
astronauts' workplace for the next two-plus weeks.

  There they began setting up systems to conduct more than 40 diverse
experiments representing involvement in the mission of 11
nations. These experiments are designed to examine how human beings
and other organisms, as well as various materials, change in the
weightless environment of space.

    This first flight day has been a fast-paced one: LMS Mission
Scientist Dr. Patton Downey, characterizing the flight as a "marathon
mission," said "today was the busiest first shift of activities we've
ever had for Spacelab. Virtually every experiment on board either had
its equipment activated or checked out."

    Just two hours after launch, Payload Specialists Dr. Jean-Jacques
Favier of France and Dr. Robert Thirsk of Canada began the mission's
important human physiology studies by donning electrodes and sensors
to monitor their eye, head and torso movements.

     Because many astronauts experience motion sickness in space
particularly for the first several days of flight as they adapt to the
weightless environment researchers hope the results of this study
could help astronauts avoid movements that contribute to motion
sickness. That could also lead to practical ways on Earth to avoid
motion sickness in our cars, boats or on planes. The experiment,
called the Torso Rotation Experiment, was designed by Dr. Douglas Watt
of McGill University in Montreal, Canada.

    Mission Specialists Dr. Charles E. Brady and Dr. Richard Linnehan,
who joined their two crew members in the early afternoon in the motion
sickness study, also participated with Favier and Thirsk in initial
flight tests to measure muscle strength and control.

    Researchers have found that muscle fibers become smaller, or
atrophy, in the absence of gravity. On previous missions, loss of
muscle and a reduction in fiber size have been documented in numerous
studies.  Fortunately, these responses to microgravity seem to be
short-lived, disappearing when astronauts return to Earth. But the
effects of long- duration spaceflight on muscles and bones remains
unknown. A series of six tests on this mission three sponsored by NASA
and three by the European Space Agency will continue investigations in
this area.

    This series of experiments is conducted on the Torque Velocity
Dynamometer, a device somewhat akin to but more highly sophisticated
than exercise equipment found in a gym. The device provides precise
measurements to calculate levels of muscle performance and function,
including strength, the amount of force produced and fatigue.

    Initial blood samples have been drawn from four payload crew
members: Favier, Thirsk, Brady and Mission Specialist Dr. Richard
Linnehan. The blood samples will be used by scientists conducting the
human physiology investigations. Information collected from these life
science investigations will help prepare crews for longer duration
missions as human activity in space expands.

    Just as life science experiments onboard Columbia may unlock
secrets of microgravity's effect on humans, the LMS microgravity
experiments are focused on understanding the subtle influences at work
in the gravity- free environment during processing of various
materials, such as samples of specialized alloys. During previous
missions, scientists found that materials processed on orbit revealed
underlying secrets that were masked or distorted by gravity in
Earth-based laboratories.

    Today, Favier activated the Advanced Gradient Heating Facility
furnace which will be used to solidify alloys and crystals in a number
of experiments designed to understand the conditions at which the
structures of freezing materials change in the solidifying process.
Researchers hope the investigations with this new furnace will
increase knowledge of the physical processes involved in
solidification, and lead to improvements in materials processing on
Earth.

    For the mission's first experiment using this high-temperature
facility, Payload Commander Susan Helms this afternoon placed an
experiment cartridge into the furnace to study the transition in
solidifying metal mixtures from ordered, long, column-like grains to
unordered, round grains. The principal investigator for the experiment
is Dr. Denis Camel of the French Atomic Energy Commission in Grenoble,
France.

    With today's launch of Columbia on the LMS mission, NASA and its
international partners are on the way toward a significant, short-term
goal to discover new applications in cutting-edge areas of science.
Similar to the way business will be conducted on the Space Station,
the international crew aboard Columbia is working together as a single
shift to ensure a consistent, daily pattern of activities.  Also very
similar to future Space Station operations, LMS researchers from the
United States and abroad are sharing resources such as crew time and
equipment.

    Some LMS science teams are huddled at Marshall Center's Spacelab
Mission Operations Control Center, as in previous missions. But for
the first time, most of the science teams are working from their bases
all over the world, and are linked to Marshall Center by a
sophisticated teleconferencing network.

    LMS Mission Manager Mark Boudreaux of Marshall summed up this
meticulously planned mission as having "the key ingredients to take us
into the next era of space exploration: the International Space
Station."

    With the Spacelab program moving toward its conclusion, Mission
Scientist Downey said, "The scientific investigations of this mission
resemble the operations envisioned for the Space Station more than any
previous mission. The mixture of scientific disciplines, international
participation, and shortened time for the development of this mission
are an ideal precursor for the Space Station."

  STS-78 Flight Day 2 Highlights:

 On Friday, June 21, 1996, 7:00 a.m. CDT, STS-78 MCC Status Report #3
reports: 

  STS-78 Commander Tom Henricks told ground controllers this morning
that Columbia's "free fallers" are starting their first full day of
life science and microgravity experimentation with a great attitude.

  Henricks' comment followed a 4:49 a.m. CDT wake-up call featuring
one of his favorite songs, "Free Falling," sung by Tom Petty and
Heartbreakers. The term "free fallers" is used because the
microgravity conditions that are the basis of the flight's
investigations are possible because the shuttle is in a state of
perpetual free-fall around the Earth. More than 40 experiments being
conducted in the Spacelab module will look into the physiological
changes that take place in the human body during spaceflight and will
utilize the microgravity environment to study materials science
techniques.

  Today, Henricks will work with the Bubble Drop Facility while Pilot
Kevin Kregel works at a computer workstation that assesses human
behavior changes during long-duration space flight. The scientists on
board, Rick Linnehan, Susan Helms, Chuck Brady, Jean-Jacques Favier
and Bob Thirsk will work with neurological and cardiovascular
experiments.

  All systems aboard Columbia and in the Spacelab are performing well
as the orbiter circles the Earth every 90 minutes at an altitude of
170 miles. Columbia is in a gravity gradient attitude, with its tail
pointing to the ground and its belly facing in the direction of travel
so that the fewest possible thruster firings are needed to prevent the
sensitive microgravity experiments from being disturbed.

 On Friday, June 21, 1996, 5:00 p.m. CDT, STS-78 MCC Status Report #4
reports:

  The STS-78 astronauts spent their first full day in orbit continuing
the scientific investigations housed in the Spacelab module and on
Columbia's middeck.

  Columbia continues to function well and activities by the flight
control team in Mission Control have focused mainly on assisting
investigators with the array of life and materials science experiments
being conducted on board.

  Late this afternoon, Payload Specialist Bob Thirsk replayed video of
some of the life science investigations conducted in the Spacelab
module, discussing the experiments and the data that will be provided
to ground-based researchers.

  The crew is scheduled to begin an eight-hour sleep period at 8:49
p.m. CDT today and will wake for the third day of the mission at 4:49
a.m. CDT Saturday. The crew will continue its work with the life and
microgravity science investigations shortly after 8 a.m. CDT Saturday.

  Columbia is in a 167 statute mile high circular orbit, completing a
revolution of Earth every hour and a half.

 On Friday, June 21, 1996, 6:30 p.m. CST, STS-78 Payload Status Report #01
reports: (001/07:30 MET)

  Settling into the first full workday of their mission, the
seven-member crew of Space Shuttle Columbia have had a busy and
productive day.

  As evident from live, televised views today, the Spacelab has been
transformed by the crew into an operational, sophisticated multi-use
research laboratory.  The busy astronauts (each with individual,
specific tasks) could be seen floating over and beneath one another as
they went about their work in the Spacelab efficiently.  That
space-borne laboratory, with a work area approximately 18 feet by 7
feet, houses most of the more than 40 diverse experiments aboard
Columbia.  Those experiments are designed to examine the effects of
weightlessness on human beings, other organisms and various materials.

  Overnight, many of the microgravity science investigations were
begun, and today the first actual sample processing run was completed
in the area of materials research.  In an experiment designed by
Dr. Denis Camel of the French Atomic Energy Commission in Grenoble,
France, a copper and aluminum alloy sample was placed in a high-
temperature furnace, called the Advanced Gradient Heating
Facility. Researchers will study the transition in solidifying metal
mixtures from ordered, long, column-like grains to unordered, round
grains.  The experiment is designed to possibly improve processing of
metals on Earth.

  Television viewers today could also see, through a microscope
onboard Spacelab, an embryo of the Medaka fish.  This hardy fish is
the focus of an experiment to help understand gravity's role in normal
animal development. Dr.  Debra Wolgemuth of Columbia University
College of Physicians and Surgeons in New York is the principal
investigator for the experiment.  The embryos are growing in the fully
automated cell culture system, called the Space Tissue Loss Module,
which was designed by the Walter Reed Army Institute of Research.

  Today all of Columbia's crew began participating in life sciences
research.  The payload crew wore sensors which continuously monitor
information 24-hours a day, measuring muscle performance and function.
This series of experiments is conducted in conjunction with the Torque
Velocity Dynamometer, a device much like exercise equipment, which
provides precise measurements of muscle use, including strength, the
amount of force produced and fatigue.  These investigations are
designed to determine the effects of spaceflight on muscles.

  The four payload crew members today continued to provide blood,
saliva and other body samples for metabolic experiments designed to
understand the biochemical changes and effects of spaceflight on
humans.  These specimens will allow measurement of calcium intake and
loss from the body, protein metabolism and caloric intake and use.

  Three crew members (Pilot Kevin Kregel, Commander Terence Henricks
and Payload Specialist Dr. Robert Thirsk) began a study to determine
the effects of spaceflight on mental skills that are critical to
performing tasks in space.  Scientists want to determine how
information processing changes throughout the mission.

  The first of several tests of the Astronaut Lung Function Experiment
was performed.  This investigation examines spaceflight's effects on
lung function and respiratory muscles during rest and heavy exercise.
The crew also set up the Gas Analysis System for Metabolic Analysis
Physiology, which measures the types and amount of air breathed in and
out.  This investigation may lead to a better understanding of how
gravity affects the pulmonary system during exercise.

  Crew members today donned special head gear with a screen that
displays visual and motion targets.  This is for a study examining
middle ear functions and head and eye movement in microgravity, called
the Canal and Otolith Integration Studies. The experiment could lead
to a better understanding of how people maintain their balance in
space and on Earth.

  Dr. Patton Downey of the Marshall Spaceflight Center, mission
scientist for the Life and Microgravity Spacelab Mission, said today
was "the busiest day of the mission because of the desire to make a
number of measurements regarding the crew's adjustment to the first
few days and hours of flight.  This - plus the desire to check the
status of our other experiments' hardware" made this one of the
busiest days in space ever."

  STS-78 Flight Day 3 Highlights:

 On Saturday, June 22, 1996, 6:00 a.m. CDT, STS-78 MCC Status Report #5
reports: 

  With the Life and Microgravity Spacelab experiments relating to
bone-mass loss in mind, flight controllers in Houston awakened the
crew of Columbia with the song "Bad to the Bone" at 4:49 a.m. CDT.
Human physiology tests on STS-78 include the Direct Measurement of the
Initial Bone Response to Space Flight investigation, which scientists
hope to use to discover countermeasures for this detrimental effect of
space flight.  The research also could lead to treatments for the
debilitating effects of the disease osteoporosis.

  As Spacelab experiments continue today, Commander Tom Henricks and
Payload Specialist Jean-Jacques Favier will set up the bicycle
ergometer on the middeck so that crew members can exercise their
cardiovascular systems.  Henricks also will test a device designed to
permit voice control of shuttle closed circuit television, intended
for use on future missions when astronauts' hands are busy controlling
the robot arm.

  Henricks again will participate in a video teleconference as part of a
demonstration combining Shuttle communications and commercial
teleconferencing systems.  Yesterday, he remotely commanded a small
camera mounted on the CAPCOM console to get a view of the flight
control team in Houston while talking with Spacecraft Communicator
Chris Hadfield.  The demonstration should ultimately provide two-way
video, audio and interactive computer communication and application
sharing for the International Space Station.

  Columbia is continuing to provide a stable workshop for the biological
and materials science experiments, orbiting the Earth every 90 minutes
at an altitude of 170 miles in a gravity gradient attitude that
minimizes steering jet firings and disturbances to the microgravity
experiments.

 On Saturday, June 22, 1996, 5:00 p.m. CDT, STS-78 MCC Status Report #6
reports:

  Columbia's astronauts continued their work in the Spacelab module
today, as the oldest shuttle in the fleet continued to provide a
stable platform for what is planned to be two more weeks of
experiments and investigations into microgravity science.

  Late this morning, flight controllers assisted the astronauts in a
procedure to flush an ice blockage out of the Flash Evaporator System
(FES) which is used to dissipate heat from the shuttle. The procedure,
which runs warm freon through the FES, was successful and the system
is once again fully operational.  To supplement the FES, flight
controllers also deployed one of two sets of radiators mounted on the
Shuttle's payload bay doors to further radiate heat from the orbiter.

  Commander Tom Henricks and Pilot Kevin Kregel tested a device designed
to permit voice control of the Shuttle closed circuit television
system.  The Voice Command System should allow astronauts to command
the CCTV system verbally while performing other tasks. Kregel reported
that the system responded to at least 90% of his verbal commands.

  Late this afternoon, Henricks was scheduled to participate in a
video teleconference as part of a demonstration combining Shuttle
communications and commercial teleconferencing systems.  Yesterday, he
remotely commanded a small camera mounted on the CAPCOM console to get
a view of the flight control team in Houston while talking with
Spacecraft Communicator Chris Hadfield.  The demonstration should
ultimately provide two-way video, audio and interactive computer
communication and application sharing for the International Space
Station.

 On Saturday, June 22, 1996, 6:00 p.m. CST, STS-78 Payload Status Report #03
reports: (002/06:44 MET)

  Human physiology studies onboard Columbia today entered the first of
two key periods for specialized types of measurements to understand
changes in the human sleep and performance patterns in space.

  In this first of two 72-hour time blocks during the Life and
Microgravity Spacelab Mission, the four payload crew members --
Dr. Jean-Jacques Favier, Dr. Robert Thirsk, Dr. Charles Brady and
Dr. Richard Linnehan -- embarked on a first-ever, comprehensive study
of sleep, 24-hour circadian rhythms and task performance in the
microgravity environment of space.

   Scientists hope to learn what happens to astronauts' sleep patterns
and their circadian clocks while in space. The study's principal
investigator, Dr. Timothy Monk of the University of Pittsburgh, said
the investigation is essential "if we are really going to do long-term
exploration in space. We have to know," he said, "what happens when we
remove ourselves from real-time cues."

   Astronauts orbiting Earth experience 16 sunrises and sunsets in a
24-hour period. This significantly affects their normal time
cues. Results of this study may also benefit people on Earth by
helping workers whose normal work and sleep schedules change as their
work shift changes.

 During the investigation, the four payload crew members wear a sleep
cap with electrodes that measure brain waves, eye movements and muscle
activity while they sleep.

  Four crew members -- Linnehan, Brady, Favier and Payload Commander
Susan Helms -- continued their participation today in the human
physiology musculoskeletal experiments. Linnehan, Brady and Favier
wore sensors for 24 hours, continuously monitoring their muscle
activity. They also performed right leg tests on the Torque Velocity
Dynamometer, a sophisticated exercise device that provides precise
measurements of muscle strength, power and endurance. This is one of
several studies on Columbia's Spacelab mission that are designed to
determine how spaceflight effects muscle size and strength.

 A special device which stimulates muscles electrically was used for
the first time during the mission today by Linnehan and Favier. They
attached the Percutaneous Electrical Muscle Stimulation electrodes to
their left legs, a means of applying precise electrical stimuli to
cause involuntary muscle contractions. Investigators are obtaining
information from the muscle contractions that will help them interpret
why muscle loses strength.

   An important space biology experiment began today when Payload
Commander Helms carefully bent 20 loblolly pine seedlings growing in
the Plant Growth Facility. When trees growing on Earth bend and then
right themselves, they form "reaction" wood which is structurally
inferior.  Biologists will study the cellular structures of these
6-inch seedlings. They hope to learn how to prevent reaction wood
formation on Earth which could help the lumber and paper industry.

  Microgravity research again was the focus of scientific activity
overnight. A fluid physics experiment in the Bubble Drop and Particle
Unit produced results which may aid in understanding such fundamental
processes as evaporation and condensation.

  Dr. Johannes Straub of the University of Munich, who designed the
experiment, said results from this study may refine a long-standing
physics theory. In the test cell containing the experiment onboard
Columbia, a small heater emitted an electrical charge into a liquid
Freon supersaturated with gas, producing a single bubble by
boiling. For the investigation, scientists measure its development and
then reverse the process by increasing pressure to cause condensation
in which the gas bubble is redissolved into the liquid. Said Straub,
who is overseeing his experiment from the Marshall Space Flight Center
in Huntsville, Ala.: "Eventual applications of what is learned from
this basic study will benefit designers of power and chemical plants
and of air conditioners, among others."

   Also in the microgravity research area, processing of another
specialized material is under way in the high-temperature furnace.
Dr. Doru Stefanescu of the University of Alabama in Tuscaloosa, who is
the principal investigator of the experiment, has a sample of pure
aluminum reinforced with zirconia particles that is being
processed. The experiment is designed to better understand the physics
of liquid metals containing ceramic particles as they solidify. It is
hoped the results will lead to improved materials processing on
Earth.

  STS-78 Flight Day 4 Highlights:

 On Sunday, June 23, 1996, 7:00 a.m. CDT, STS-78 MCC Status Report #7
reports: 

  Columbia's astronauts are continuing work this morning with the human
physiology and materials science experiments of the Life and
Microgravity Spacelab mission.

  Today's research will concentrate on measurements of leg and arm
muscle power with the Torque Velocity Dynamometer, pulmonary function
with the Astronaut Lung Function Experiment and effects of
microgravity exercise with the bicycle ergometer and its associated
instruments.

  Crew members will work several small in-flight maintenance procedures,
including the replacement of a blown fuse in the Bubble Drop Particle
Unit and will attempt to adjust a balky door on the Thermoelectric
Holding Module, which maintains samples at the correct temperatures.

  In addition, Commander Tom Henricks, Pilot Kevin Kregel and Mission
Specialists Rick Linnehan and Susan Helms will be interviewed by CNN
at 10:04 a.m. Central time.

  The crew's day began at 4:24 AM Central time with a 1980 rendition of
"Flight of the Bumblebee" as played by the U.S. Air Force Academy's
Drum and Bugle Corps. Helms, a cadet at the Air Force Academy at the
time, played xylophone on the recording.

  Overnight, one of two sets of radiators mounted inside the Shuttle's
payload bay doors remained deployed to help dissipate excess heat. The
radiator was deployed before the crew went to sleep Saturday night
after an ice blockage temporarily hindered the operation of the Flash
Evaporator System (FES), also used as a Shuttle cooling system. The
FES resumed full function after the ice was flushed using warm freon.

 On Sunday, June 23, 1996, 5:00 p.m. CDT, STS-78 MCC Status Report #8
reports:

   In addition to continuing work in the Spacelab module, Columbia's crew
today also spent time sharing the progress of its mission with a
varied audience.

   The astronauts discussed the flight during an interview with the Cable
News Network this morning and Payload Commander Susan Helms took time
this afternoon to speak with students at Eisenhower Middle School in
San Antonio, Texas. The school has a "Young Astronaut Program" that
has had students launch a model rocket to an altitude of 15,000 feet,
and have assembled a permanent amateur satellite station.

   Late in the afternoon, Commander Tom Henricks replayed a video taken
earlier in the day of Mission Specialists Chuck Brady and Rick
Linnehan and Payload Specialist Jean- Jacques Favier as they prepared
to begin their fourth day on orbit.  Henricks also shared video of his
work with the Performance Assessment Workstation.  PAWS uses a pre-
programmed laptop computer to test the astronaut's response to a
variety of information and images to provide data on how critical
thinking skills may be affected by the microgravity environment of
space, or by long hours and shift work for people on Earth.

 On Sunday, June 23, 1996, 6:00 p.m. CST, STS-78 Payload Status Report #04
reports: (MET 003/08:00:00)

  During their third work day the crew of the Space Shuttle Columbia
resumed experiments focusing on human physiology studying the effects
of microgravity on areas such as muscle and circadian rhythms.

  The circadian studies focus on how living in space affects sleep
patterns and mental and physical functions. A series of performance
and mood tests, which the crew took using a laptop computer assessed
the quality of their sleep last night. Mission Specialists Charles
Brady and Dr. Richard Linnehan, and Payload Specialists Dr. Robert
Thirsk and Dr.  Jean-Jacques Favier participated in the experiment. 

  A related experiment, conducted daily, that studies the effects of
spaceflight on the thought processes was also performed. The crew
members participated in mental exercises, which show the speed and
accuracy of their responses to rotated letters, math problems, letter
sequences and rotated images. One of the harder challenges in the
tests for the crew is rapidly switching attention between two
tasks. The results of this study will help researchers to determine
levels of mental fatigue and alertness.

   Early this morning, a team of scientists in the Spacelab 
Mission Operations Control Center at the Marshall Space 
Flight Center in Huntsville, Ala., monitored and controlled 
an experiment in the Bubble Drop Particle Unit.

  This study, lead by principal investigator Dr. Antonio 
Viviani of Italy's Second University of Naples, looks at the 
surface tensions and interactions of gasses and liquids in 
the weightlessness of space. Various sized air bubbles are 
injected into a water-and-alcohol solution with temperature 
graduations ranging from hot to cold. From this 
investigation, researchers hope to learn how to control 
defects in many aspects of materials manufacturing. This 
could lead to production of better and stronger metals, 
alloys, glasses and ceramics.

  Later today, Favier installed a test container into the 
Bubble, Drop and Particle Unit for a fluid processing 
experiment designed to monitor the flows of individual liquid 
components induced by surface tension-driven convection. The 
understanding of this process is important for manufacturing. 
Dr. Jean-Claude Legros of Belgium's Microgravity Research 
Center at the Free University of Brussels is principal 
investigator of the study.

  A component of the unit is having a problem that limits its 
operation. Troubleshooting of the unit is planned for later 
in the mission. Meanwhile, researchers continue to use the 
facility to conduct experiments unaffected by the problem.
Participation in the Astronaut Lung Function Exercise 
experiment continued today. The container supplying oxygen 
for one part of the experiment was found to be only partially 
full. The astronaut continued that part of the experiment 
until the oxygen container was empty. The rest of that 
experiment is continuing as planned.

  Favier, Thirsk and Brady continued tests in the mission's 
important musculoskeletal experiments. Crew members, who 
continuously wear sensors to monitor their muscle activity, 
performed a number of exercises today on a complex device 
called the Torque Velocity Dynamometer. The device provides 
precise measurements of muscle strength, power and endurance.
In the high-temperature furnace, called the Advanced 
Gradient Heating Facility, processing concluded for an 
experiment involving solidification of pure aluminum 
containing zirconia particles. The experiment "went 
"perfectly," said principal investigator Dr. Doru Stefanescu 
of the University of Alabama in Tuscaloosa. He and his 
research team monitored experiment progress from the Spacelab 
Mission Operations Control Center. This experiment, said 
Stefanescu, "may lead to more inexpensive ways to  make 
mixtures of metals and ceramics -- particularly for the metal 
casting industry. We hope to find ways to help manufacturers 
make composite products with superior quality."

  STS-78 Flight Day 5 Highlights:

 On Monday, June 24, 1996, 6:00 a.m. CDT, STS-78 MCC Status Report #9
reports: 

   Microgravity research today aboard Columbia will concentrate on the
use of the gradient furnace and the Bubble Drop Particle Unit to study
materials processing, and on studies of human muscles and balance
mechanisms.

  STS-78 crew members also will have opportunities to exercise and
contact friends and family members on the ground with the Shuttle
Amateur Radio Experiment (SAREX).

  Late in the crew's day, Commander Tom Henricks and Pilot Kevin
Kregel will reassign one of the shuttle's five general purpose
computers (GPC) to run the backup flight software (BFS). The procedure
is designed to ensure that a fully functional backup computer will be
available during reentry and landing. The GPC assigned to run the BFS
software exhibited intermittent transients during the climb to orbit,
but is not affecting orbiter operations or mission duration.

  Flight controllers woke the crew at 4:08 a.m. CDT with the song
"Space Oddity," which mentions a fictitious astronaut named "Major
Tom." Tom Henricks is an Air Force colonel.

 On Monday, June 24, 1996, 6:00 p.m. CST, STS-78 Payload Status Report #05
reports: (MET 004/07:00:00)

  The Canal and Otolith Integration Studies, experiments 
which measure the effect of the weightless environment on the 
vestibular system of the inner ear, occupied much of today's 
work schedule for the four payload crew members aboard the 
Space Shuttle Columbia.  These studies examine the effects of 
microgravity on the vestibular system of the inner ear and 
the resulting changes in eye-hand-head coordination.

  Payload Commander Susan Helms, Mission Specialist Dr. 
Richard Linnehan, and Payload Specialists Dr. Robert Thirsk 
and Dr. Jean-Jacques Favier wore high-tech, modified ski 
goggles which helped record their eye and head movements as 
they tracked illuminated targets displayed on the goggles' 
surface.  The operations were conducted both while the crew 
members remained in a fixed position seated on an exercise 
bicycle, called an Ergometer, and when they were allowed to 
free-float in the Spacelab cabin.

  Using these procedures, the crew members completed a series 
of 17 objectives designed to test spatial orientation in the 
absence of a gravitational reference.

  Also, Mission Specialist Dr. Charles Brady joined Thirsk, 
Linnehan and Favier in conducting musculoskeletal tests that 
measured arm and hand-grip strength.  With their arms 
strapped into the Torque Velocity Dynamometer -- which 
resembles an arm or leg exercise machine found in many health 
clubs -- the crew members curled and extended their arms at 
the elbow while the machine provided resistance.   The crew 
members also participated in tests of their motor skills to 
define how well specific muscle groups are performing after 
an extended time in the microgravity environment.

  The crew completed the final hours of the first of two 72-
hour sleep study periods as part of the human sleep and 
circadian study. This research is looking at how life in 
space affects sleep patterns and mental alertness.  The crew 
members completed wake-up and end-of-shift questionnaires, as 
well as alertness and mood tests before each meal and 
throughout the day.

  Principal Investigator Dr. Timothy Monk of the University 
of Pittsburgh said the study is critical to understanding 
what happens when the body's biological clock is altered.  As 
with all the experiments, the sleep study has direct 
relevance to life on Earth as sleep disorders are often 
caused by shift-work changes and jet lag, Monk explained. 
"And aging and depression are related to the clock going 
wrong," he added.  

  LMS Mission Program Scientist Dr. Victor Schneider said 
today scientists and researchers "are very pleased with how 
the crew is working with us to achieve the goals of this 
mission."

  Schneider, of NASA Headquarters in Washington, D.C., said 
previous life science studies have shown the types of 
physiological changes that occur in spaceflight. But those 
limited studies have not revealed the 'whys' of those 
changes. With the LMS mission's comprehensiveness and 
sophisticated level of capabilities, however, it is now 
possible to move beyond and explore more fully the 'whys.'"

  In one major area of microgravity research being conducted 
on this mission, investigators today looked to a 
polycrystalline sample in the Advanced Gradient Heating 
Facility for information on how to combine liquid metal alloy 
components into a precise, well-ordered solid structure. 
Knowledge gained from melting and resolidifying this compound 
may help manufacturers to produce higher quality metal alloys 
and semiconductor crystals.  Principal Investigator Dr. 
Thierry Duffar of the French Atomic Energy Commission of 
Grenoble, France, and his team monitored and controlled this 
experiment from Spacelab Operations in Huntsville, Ala.  He 
was in communication with his backup support group in France 
during this experiment.

 On Monday, June 24, 1996, 5:00 p.m. CDT, STS-78 MCC Status Report #10
reports:

  Scientific investigations continued today with Columbia providing a
trouble-free platform for the experiments housed in the Spacelab
module on Columbia's middeck.

  This afternoon, Mission Commander Tom Henricks and Pilot Kevin
Kregel successfully moved the backup flight software from its host
computer to a second computer in an effort to determine whether a
computer error early in the flight was due to software or
hardware. The astronauts reassigned the Backup Flight Software (BFS)
from General Purpose Computer 5 (GPC5) to GPC2.  Following the
reassignment of the software, the data were dumped to the ground for
review and analysis by the flight control team. GPC 5 is in "freeze
dry" mode, which means although it is operating, it is not issuing any
commands. Flight controllers will watch GPC 5 and gather telemetry on
its operation over the next 48 hours.

  Henricks again participated in a demonstration of the two-way
teleconferencing system being flown on board Columbia.  He was joined
by Payload Specialists Bob Thirsk and Jean-Jacques Favier who viewed
video of their June 20 launch from Kennedy Space Center.  In the
flight control room, Spacecraft Communicator Chris Hadfield was joined
by members of the International Space Station Program Office to
observe the demonstration which has applications for use on both
Shuttle and Space Station missions.

  Payload Commander Susan Helms today congratulated the United States
Air Force Academy Class of 2000, due to start its four-year training
in just a few weeks. Helms also congratulated the Academy on the 20th
anniversary of the first class to include female cadets.  Helms was a
member of that class of 1980, arriving at the Air Force Academy on
June 28, 1976. She graduated with a bachelor of science degree in
aeronautical engineering.

  STS-78 Flight Day 6 Highlights:

 On Tuesday, June 25, 1996, 7:00 a.m. CDT, STS-78 MCC Status Report #11
reports: 

  Columbia's seven astronauts will get a break from their work with
the Life and Microgravity Spacelab experiments, taking the second half
of today off to recharge their batteries a third of the way through
what is expected to be a 17-day flight.

  Before taking time off, crewmembers will perform status checks on
the 40 Spacelab experiments, exercise on the bicycle ergometer and
work on several in-flight payload maintenance procedures.

  The maintenance work will continue trouble-shooting on an electrical
circuit in the Bubble Drop Particle Unit fluids experiment, strap down
the Torque Velocity Dynamometer used to measure muscle power and
replace a fuse on the Advanced Gradient Heating Facility that is
working on semiconductor and alloy solidification techniques.  The
problems are considered minor and are having little effect on data
gathering from the experiments.

  The crew also is scheduled to connect with school children in
Colleyville, Texas, through the Shuttle Amateur Radio Experiment, and
with family members through normal shuttle air-to-ground channels.

  The astronauts were awakened at 3:34 a.m. CDT to the sounds of
"Blinded Me with Science," and will go to sleep at about 7 tonight.
Their sleep schedules are shifting slightly to accommodate landing day
activities.

 On Tuesday, June 25, 1996, 5:00 p.m. CDT, STS-78 MCC Status Report #12
reports:

  Early today, Columbia's astronauts performed status checks on the
life and microgravity experiments and conducted a brief maintenance
procedure to trouble-shoot an electrical circuit in the Bubble Drop
Particle Unit investigation.

  The crew also enjoyed four hours of off-duty time today, taking the
opportunity to relax after five days of work with the life and
microgravity science investigations being conducted on board.

  Flight controllers routinely schedule off-duty time for shuttle
missions longer than 10 days duration.  STS-78 is currently targeted
for a 16-day flight, with the possibility of a one- day extension for
science activities.

  The seven astronauts will begin their sleep period at 7:09
p.m. Central time today, awakening at 3:09 a.m. Wednesday to begin
Flight Day 7 on orbit. The oldest space shuttle in the fleet continues
to perform well as it orbits the Earth every 90 minutes at an altitude
of 170 miles.

 On Tuesday, June 25, 1996, 6:00 p.m. CDT, STS-78 Payload Status Report #06
reports: (MET 005/06:00:00)

  The sixth day of the Space Shuttle Columbia mission was 
marked by an abbreviated work shift for the crew, and a 
planned half-day off to ensure they stay at peak efficiency 
for the remainder of what may be a record-setting Shuttle 
mission.

  Following a morning of scheduled experiments and lunch, the 
seven-member crew enjoyed four hours of leisure time. 
Throughout the afternoon each had the opportunity to talk 
with their family for 15 minutes.

  The crew is also slated for a second half-day off on the 
10th day of their mission. Their meticulously planned, 
comprehensive flight and activity schedules are the product 
of many people and many months of planning -- primarily based 
on the accumulated experience from previous flights.
For future spaceflights, scheduling of crews' work and rest 
schedules may be refined based on the knowledge being gained 
on this mission. The Columbia crew is participating in a 
series of investigations that focus on how living and working 
in space affects sleep patterns and mental and physical 
functions. A related experiment, conducted on alternating 
days, studies the effects of spaceflight on thought 
processes.

  Before their four-hour rest period this afternoon, the crew 
attended to a number of operations involving microgravity 
research. An experiment known as the Oscillatory Marangoni 
Instability investigation was removed from the Bubble, Drop 
and Particle Unit today by Shuttle Commander Tom Henricks. 
The experiment is headed by Dr. Jean-Claude Legros of the 
Microgravity Research Center at Belgium's Free University of 
Brussels.  While varying levels of heat to the sample, 
researchers tracked the fluid flows between the layers of a 
unique three-layered liquid system. The experiment's goal is 
to study flows caused by changing surface tensions as liquids 
approach solidification.  At certain temperatures, the flows 
often become irregular, leading to layer instability. Aided 
by precise temperature readings and video images tracking the 
events, researchers hope to create a model of the flows and 
to develop a method for maintaining stability. This could 
lead to the development of higher-quality semiconductors and 
other electronics products.

  On Monday, crew members were successful in isolating an 
electrical short affecting the Bubble, Drop and Particle 
Unit. The short did not affect today's experiment.  Based on 
their findings, the plan is for the crew later this week to 
install a bypass power line to circumvent the short. In 
preparation for that maintenance, engineers at the Marshall 
Space Flight Center in Huntsville, Ala., have been rehearsing 
the procedure on a model of the Bubble, Drop and Particle 
Unit.

  In another of the microgravity research areas, an 
experiment cartridge was inserted into the Advanced Gradient 
Heating Facility -- a high-temperature furnace -- for 
processing of an aluminum and indium sample. The focus of 
this 35-hour-long experiment run is to obtain a uniform mix 
of indium fibers in the aluminum. Controlling the internal 
structures of these materials during the solidification could 
lead to improved alloys for engineering, chemical and 
electronic applications.

  Mission Specialist Dr. Richard Linnehan and Payload 
Commander Susan Helms earlier today performed a diagnostic 
check of a previous sample cartridge that had been placed in 
the Advanced Gradient Heating Facility. That experiment is 
intended to study the segregation of components during the 
formation of alloys. The study of the sample indicated that 
there was an open circuit in the sample. Discussions are 
being held to determine if this indeed is a problem. While a 
resolution is being sought, processing of other samples 
continues, as only one of 14 samples on the flight requires 
the electrical pulse.

  Helms used a video microscope to beam images to Earth of 
the Medaka fish embryos that are developing in a growth 
facility onboard Spacelab. Investigators are tracking the 
embryos' growth. Periodically, groups of the Medaka embryos 
are preserved for testing on return to Earth. This will 
enable investigators to test a hypothesis that gravity is 
required for normal embryo development. Since the embryos are 
transparent, investigators can easily follow development of 
internal organs. Principal investigator for the experiment is 
Dr. Debra Wolgemuth of the Columbia University College of 
Physicians and Surgeons in New York. As humans undertake even 
longer duration spaceflights, understanding the impact of 
microgravity on vertebrate development becomes increasingly 
important.

  STS-78 Flight Day 7 Highlights:

 On Wednesday, June 26, 1996, 7:00 a.m. CDT, STS-78 MCC Status Report #13
reports: 

  After a half day of off-duty relaxation, Columbia's crew went back to
work this morning on the 41 science investigations associated with the
STS-78 Life and Microgravity Spacelab mission.

  Mission Control played "Chain Gang" as the wake-up music for the crew
at 3:09 AM Central time for its seventh day in space, and spacecraft
communicator Bill McArthur told the astronauts the song was chosen to
remind them that it is "back on the chain gang today." Commander Tom
Henricks told McArthur the crew was ready to return to its
multifaceted research studies into the effect of weightlessness on the
human body and materials.

  In addition to continuing scientific investigations, Payload Commander
Susan Helms will take time out to speak with Portland, Ore.,
television station KGW-TV later today. Helms considers Portland to be
her hometown.

  Pilot Kevin Kregel will discuss the progress of the fifth Shuttle
mission of the year with students at Bethlehem Central Senior High
School in Delmar, N.Y., using the Shuttle Amateur Radio Experiment,
and Payload Specialist Bob Thirsk will take up the ham radio gear to
make contact with students at the Saskatoon Public Aerospace Education
school in Saskatchewan, Canada.

  Columbia's astronauts have also been alerted to keep a sharp eye out
for forest fires in Arizona near the Grand Canyon, as part of their
Earth observation photography.

  The oldest space shuttle in the fleet continues to perform in
excellent fashion on its 20th mission, with no significant systems
problems being tracked by flight controllers.

 On Wednesday, June 26, 1996, 5:00 p.m. CDT, STS-78 MCC Status Report #14
reports: 

  Columbia's crew completed another day of scientific investigation in
the Spacelab module as the orbiter circled the Earth at an altitude of
about 170 miles.

  In addition to their work in the Spacelab module, the astronauts took
time today for a scheduled interview with KGW Television in Portland,
Oregon.  The event was cancelled due to technical difficulties at the
television station, but the crew used the time to discuss the progress
of the mission to date and their personal feelings about their time in
space.

  Early today, as Columbia passed over the area of the Grand Canyon in
Arizona, Payload Commander Susan Helms reported that the crew could
see smoke from the forest fires burning in that area.

  On schedule for the crew tomorrow is work with the Human Behavior and
Performance Experiments which gauges the ability of the human body to
respond to changes in its environment, such as stress, fatigue or
sickness.  The astronauts' responses to computerized performance tests
will be measured and compared to pre- and post-flight data.

  The crew also will continue as test subjects in a series of
investigations that seek to understand the effects of microgravity on
the human musculoskeletal system.

  Thursday morning, Helms will talk with KNX Radio in Los Angeles to
discuss the mission's progress. That interview is set for 8:59
a.m. Central time.  In the afternoon, Commander Tom Henricks and
Payload Specialist Jean-Jacques Favier will participate in an
educational event with students in Paris.

  The oldest space shuttle in the fleet continues to perform well on its
20th mission, with no significant systems problems being tracked by
flight controllers.

 On Wednesday, June 26, 1996, 6:00 p.m. CDT, STS-78 Payload Status Report #07
reports: (MET 006/08:00:00)

  Approaching the half-way mark of a possible record-setting Space
Shuttle mission, the crew of Columbia continues its full schedule of
life science and microgravity experiments.  The seven-member crew
today began the second of three planned cycles of human physiology
investigations, as part of a research effort which scientists hope
will lead to improved adaptation to living and working in space.

  In the microgravity area, two experiments for Dr. R.S.  Subramanian of
Clarkson University in Potsdam, N.Y., were started today. The first
test, to study the movement of bubbles and drops in a liquid, was
completed earlier today.  Payload Specialist Dr. Jean-Jacques Favier
then successfully removed the container from the Bubble, Drop and
Particle Unit, and installed another container for the experiment,
which is now processing. This second portion of his experiment is
focusing on drops of liquid suspended in another liquid.  Findings
from the investigation may lead to the production of better-quality,
bubble-free alloys on Earth. This could help engineers design systems
for the recycling of waste material in space, essential during long-
duration missions.

  Today the crew started the first of two parts of a maintenance
procedure to bypass a possible short in the Bubble Drop Unit power
supply. Repair will be performed after Dr. Subramanian's experiment is
completed.

  Three crew members -- Mission Specialists Dr. Charles Brady,
Dr. Richard Linnehan and Favier -- early today resumed musculoskeletal
experiments on the Torque Velocity Dynamometer. The study is intended
to determine how spaceflight affects muscle size and strength. With
sensors monitoring muscle activity, they performed both arm and leg
exercises. Measurements were taken of muscle strength, power and
endurance.

  Favier, Linnehan, Brady and Payload Specialist Dr. Robert Thirsk,
wearing head and torso sensors, resumed the Torso Rotation Experiment
to determine how eye, head and body coordination is changed by longer
stays in space. Today's tests moved into the second of three stages of
the experiment. Results could help researchers identify causes of
motion sickness during space flight, develop counter measures and lead
to practical ways on Earth to avoid motion sickness in cars, boats, or
aircraft. The experiment is designed by Dr. Douglas Watt of McGill
University in Montreal, Canada.

  Shuttle Commander Tom Henricks, Pilot Kevin Kregel, and Thirsk and
Favier continued their participation today on the Performance
Assessment Work Station. In the experiment, a laptop computer displays
exercises to test their mental ability by measuring their responses to
operational tasks and critical thinking skills. The tests are
conducted on alternating days. Findings will help planners to schedule
crew activities during peak performance periods, increasing
productivity.

  In another area of microgravity research, Brady and Payload Commander
Susan Helms began an experiment today in the Advanced Gradient Heating
Facility aimed at controlling the internal structure of aluminum and
indium alloys during solidification. The research may lead to new
alloys for engineering, chemical and electronic applications. The
experiment is guided by Dr. Barry Andrews of the University of Alabama
at Birmingham.

  Lung function tests also continued today aboard Columbia.  This
experiment, headed by Dr. John West of the University of California
San Diego, may lead to a better understanding of how gravity affects
the pulmonary system during rest and heavy exercise. Crew members this
afternoon connected an alternative oxygen supply to the lung
experiment device. The alternative source of oxygen allowed completion
of today's pulmonary test to measure the diffusion capacity of the
lung.  This is the ability of gases to move from the air spaces into
the blood and vice versa. Included as subjects in the testing today
were both the commander and pilot.

  STS-78 Flight Day 8 Highlights:

 On Thursday, June 27, 1996, 7:00 a.m. CDT, STS-78 MCC Status Report #15
reports: 
  
  Life and Microgravity Spacelab experiments are continuing today as
Columbia's astronauts document how space flight is affecting their
minds and bodies.

  Work will concentrate on sessions at the Human Behavior Workstation,
which measures the ability of the astronaut to respond to changes in
his or her environment. The crew will also conduct investigations with
the Astronaut Lung Function Experiment, to measure the effects of
microgravity and heavy exercise on pulmonary capability, and the
Torque Velocity Dynamometer, which measures leg muscle strength.

  The seven STS-78 astronauts were awakened shortly before 3 AM Central
time today to the sound of "Every Breath You Take, Every Move You
Make" by Police -- played in honor of the Lung Function experiment and
the flight controllers in Mission Control overseeing what is expected
to be the longest Shuttle flight in history. A decision by mission
managers to extend the flight to 17 days for additional science will
likely be made over the weekend after consultations with payload
managers at the Marshall Space Flight Center in Huntsville, Alabama
and a review of Shuttle systems.

  Payload Commander Susan Helms is scheduled to be interviewed by KNX
Radio in Los Angeles at 8:59 a.m. Central time and Commander Tom
Henricks and Payload Specialist Jean-Jacques Favier will participate
in an educational discussion of the mission's scientific aspects with
French students at a Paris technical school at 2:39 p.m.

  Columbia again is orbiting with its tail to the Earth to minimize
disturbance to the microgravity experiments. There are no problems
being tracked aboard the oldest orbiter in the Shuttle fleet.

 On Thursday, June 27, 1996, 5:00 p.m. CDT, STS-78 Payload Status Report #08
reports: (MET 007/07:00:00)

  As the crew of the Space Shuttle Columbia today entered its second
week in space, the seven crew members conducted experiments primarily
focusing on the effects of weightlessness on human physiology.
Results from the studies of muscle activity, performance and sleep
will help future mission planners organize crew schedules for greater
efficiency and productivity.

  The crew continued the Astronaut Lung Function Experiment extensively
today.  Payload Commander Susan Helms, Mission Specialists Dr. Richard
Linnehan and Dr. Charles Brady, and Payload Specialist Dr. Robert
Thirsk all took part in the experiment, headed by Dr. John West of the
University of California in San Diego.  The experiment may lead to a
better understanding of how gravity affects the pulmonary system
during rest and heavy exercise. According to the experiment's
co-investigator, Dr. G.K. Prisk, also of the University of California
in San Diego, today's lung investigations followed "excellent runs"
Wednesday by Shuttle Commander Tom Henricks and Pilot Kevin Kregel.

  For a second consecutive day, Henricks, Kregel, Thirsk and Payload
Specialist Dr. Jean-Jacques Favier continued to enter responses to a
battery of problem-solving tasks on the laptop computer Performance
Assessment Work Station.  Information from the almost-daily tests of
the crew's mental function abilities will be used to create future
crew schedules, taking advantage of peak mental performance periods.
This morning Brady, Linnehan and Favier moved into a second
consecutive day of musculoskeletal experiments on the Torque Velocity
Dynamometer. They completed a series of left leg exercises while
sensors monitored muscle activity. Crew members have used the
dynamometer throughout the mission to measure how spaceflight affects
arm and leg strength, power and endurance.

  One of the life sciences experiments, tracing development of fish
embryos, will conclude during Friday's crew shift.  Thirty-six Medaka
embryos -- a hardy fish embryo known to tolerate reduced temperatures
well -- have been developing in the Space Tissue Loss Module onboard
Columbia.  Crew members have frequently monitored videos of the
embryotic development, which has been simultaneously viewed by
researchers on Earth. The goal of this experiment is to determine
gravity's role in normal development.

  Today, LMS Mission Scientist Dr. Patton Downey of the Marshall Center
said the "ultimate results of this experiment will depend on analysis
of the samples after the flight." But based on information gathered
from the video transmissions, said Downey, "it appears that the
samples in orbit are developing at a slower rate than the
ground-controlled samples."  That preliminary analysis, said Downey,
"indicates that gravity is an important factor in the development
process. One of the biggest mysteries in science is how you start from
one cell and develop different types of structures and tissues. This
experiment indicates that gravity may be an important factor in this
development."

  Two experiments continued today, in the microgravity sciences area, on
the movements and interaction between pairs of bubbles and drops in
liquids.  This morning crew members removed an experiment from the
Bubble, Drop and Particle Unit which began Wednesday afternoon that
consisted of injecting drops of Fluorinet into silicone oil.
Principal Investigator Dr. R.S. Subramanian of Clarkson University in
Potsdam, N.Y., then elected to schedule a second one-day run of his
investigation that injects inert gas bubbles into silicone oil.
Subramanian said his fluid physics experiment may help uncover
processes involving gas bubbles, liquid drops or liquid layers. He
said this research could lead to new high- strength metals and
temperature-resistant glasses and ceramics.

  On Wednesday a team of engineers and scientists at the Marshall Space
Flight Center's Payload Crew Training Complex practiced an in-flight
maintenance procedure on a model of the Bubble Drop Unit.  The
practice procedure was designed to route around a shorted cable in
that unit.  Tonight, a video of the ground practice is to be uplinked
to Columbia before the crew begins its sleep period.  Maintenance on
the unit is now scheduled to be performed by the crew on Friday.

  Teams of scientists and researchers on the ground at Marshall Center
and other sites around the world continue their 24-hour observation
and monitoring of the more than 40 experiments aboard Columbia. On
previous Spacelab missions, most of the principal researchers for
onboard experiments gathered at a central location. But for this
mission, principal remote sites are operating in the United States,
Belgium, France and Italy -- all are linked to the Marshall Center by
a sophisticated teleconferencing network.

  At Marshall Center for this mission, Dr. Graham Biddis of the European
Space Agency, who serves as operations engineer for the Advanced
Gradient Heating Facility, is helping to oversee an international
group of researchers.  "We have a multi-national team and we are
working extremely well together," said Biddis. "I am pleased with the
successful communication and cooperation among the international
teams."  This world-wide cooperative effort foreshadows similar
science operations that are planned for the future International Space
Station.

 On Thursday, June 27, 1996, 6:00 p.m. CDT, STS-78 MCC Status Report #16
reports: 

  With another day of scientific investigation behind them, Columbia's
astronauts were set to begin an eight-hour sleep period at 6:19 this
evening.

  The crew continued its work in the Spacelab module today measuring
changes in muscle strength and lung capacity, and working on a Human
Behavior Workstation that measured their ability to respond to changes
in their external environment.

  Mission Specialist Chuck Brady held an unlit Olympic Torch aloft while
exercising on the bicycle ergometer in the Spacelab today.  He was
joined by his crewmates on board in that informal salute to the 1996
Olympics which open July 19 in Atlanta.

  Also this morning, Payload Commander Susan Helms discussed the STS-78
mission in an interview with KNX Radio in Los Angeles.  In the
afternoon, science students in Paris, France asked questions of French
Payload Specialist Jean-Jacques Favier and Mission Commander Tom
Henricks.

  Late in the crew's day, flight controllers in Mission Control Houston
and investigators in the Spacelab Operations Control Center in
Huntsville, Alabama, used a videoteleconferencing system on Columbia
to demonstrate a maintenance procedure on the Bubble Drop and Particle
Unit experiment.  The system allowed the crew and ground controllers
to view a videotape of the procedure and discuss each step with each
other as they worked through the procedure.

  The astronauts will awaken to begin Flight Day 9 at 2:19 Friday
morning.  Columbia again is orbiting with its tail to the Earth to
minimize disturbance to the microgravity experiments.  There are no
problems being tracked aboard the orbiter.

  STS-78 Flight Day 9 Highlights:

 On Friday, June 28, 1996, 7:00 a.m. CDT, STS-78 MCC Status Report #17
reports: 

  Columbia's astronauts are continuing to serve as test subjects for a
host of human health and microgravity investigations today as the
STS-78 Life and Microgravity Spacelab mission nears the halfway point.

  Today's tests will concentrate on measurements of lung capacity and
muscle strength. In addition, the crew will continue its work to
operate and maintain the experiment equipment, with two more in-flight
maintenance procedures scheduled to bring the Bubble Drop Particle
Unit back to full operation.

  The crew also performed a second successful procedure to flush a small
buildup of ice from orbiter's Flash Evaporator cooling system after
the ice formed during a dump of the supply water tanks. The procedure,
which ran warm freon through the cooling system took about 20 minutes
to complete and had no impact on science operations. Otherwise,
Columbia's systems are trouble-free.

  Commander Tom Henricks, Payload Commander Susan Helms and Mission
Specialists Rick Linnehan and Chuck Brady participated in an interview
with KABC-TV in Los Angeles early this morning to discuss the progress
of their mission.

  Henricks will also offer best wishes to four engineers at Johnson
Space Center who are involved in a test of renegerative life support
systems which may be used for future space travel. The four test
subjects are living in a specially equipped chamber at JSC to gather
data on recycled air and water for three weeks. The test is scheduled
to end July 12.

  Columbia's seven astronauts were awakened shortly before 2:30 AM
Central time to "Carolina in My Mind," by James Taylor. The song holds
special significance for North Carolina native Brady, who responded
with best wishes for family and friends there.

  Columbia will reach the midway mark of its marathon mission just
before 9 PM this evening, with a decision expected by the end of the
weekend by mission managers whether to extend the flight by an extra
day for science. If the flight is extended, Columbia would land at the
Kennedy Space Center on Sunday, July 7.

 On Friday, June 28, 1996, 6:00 p.m. CDT, STS-78 MCC Status Report #18
reports: 

  While Columbia's astronauts sleep, investigators on the ground will
remotely command the Bubble Drop and Particle Unit experiment
throughout the night.  The crew will receive a wakeup call from
Mission Control at 1:54 Saturday morning.

  The bubble drop experiment is once again operating at full capacity
following a successful maintenance procedure by the crew this morning.
That procedure rerouted power to one of the test containers, bypassing
a circuit which had been causing an intermittent power short.

  Life science investigations in the Spacelab module today once again
focused on studying the astronaut's pulmonary function and muscle
strength.  Tomorrow's activities will continue those investigations
into the effects of microgravity on the human body.

  Columbia will reach the midway mark of its marathon mission just
before 9 tonight, with a decision expected by the end of the weekend
by mission managers whether to extend the flight by an extra day for
science.  If the flight is extended, Columbia's mission would end with
landing July 7 at the Kennedy Space Center in Florida.

  The flight control team has not been working any significant problems
on board Columbia, which is continuing to provide a stable platform
for the Life & Microgravity Spacelab mission.

 On Friday, June 28, 1996, 6:00 p.m. CDT, STS-78 Payload Status Report #09
reports: (MET 008/07:00:00)

  During their ninth day in flight, the Space Shuttle Columbia's crew
successfully implemented an in-flight maintenance procedure with a
specialized fluid research system, eliminating a glitch that had posed
a problem for one of the experiments.

  Late today, experiment processing resumed normally in the Bubble, Drop
and Particle Unit, after a team effort by the crew and engineers and
scientists on the ground successfully circumvented a short in the
unit's power supply.  This morning, Payload Specialist
Dr. Jean-Jacques Favier and Pilot Kevin Kregel performed the in-flight
maintenance procedure.

  Verification that the maintenance plan succeeded came after Favier and
Kregel initiated the Electrohydrodynamics of Liquid Bridges
experiment.  Headed by Dr. Dudley Saville of Princeton University,
Princeton, N.J., the experiment focuses on shape changes which occur
in a fluid bridge suspended between two electrodes.  Fluids being
studied include castor oil, clove oil, eugenol and silicone oil. The
investigation could have applications in industrial processes where
the control of a liquid column or spray is necessary, such as ink-jet
printing and polymer fiber spinning.

  Prior to maintenance on the Bubble unit, the Thermocapillary Migration
of Bubbles and Drops experiment was concluded earlier today.  The
experiment, developed by Dr.  R.S. Subramanian of Clarkson University,
Potsdam, N.Y., examined the behavior of bubbles injected in silicone
oil under a temperature gradient.

  In another area of microgravity research, processing of samples is
continuing in the Advanced Gradient Heating Facility. A minor snag
with the facility was cleared up early this morning. At 5:20 a.m.,
crew members turned the facility on and off, which served to
resynchronize the furnace's computer with a data-relay device.  The
procedure was accomplished between sample processing runs, therefore
not affecting the planned experiment schedule.

  Crew members today began the Comparative Study of Cells and Dendrites
experiment, led by Dr. Henri Nguyen Thi of the University of
Aix-Marseille, France.  This experiment melts and solidifies two
samples of an aluminum alloy at a precise growth rate. The alloys are
then rapidly cooled to preserve the shape of their solidification
boundaries.  After the mission, these samples will be cut and polished
so investigators can determine the structure's quality.  Researchers
hope to improve microscopic qualities of materials by controlling the
exact conditions at which these shapes change.

  In the mission's important experiment area of life sciences, today
Payload Specialists Dr. Robert Thirsk and Favier and Mission
Specialists Dr. Richard Linnehan and Dr.  Charles Brady completed
hand-grip, arm and leg strength tests today using the Torque Velocity
Dynamometer. The dynamometer is a sophisticated device providing
precise measurement of muscle strength, power and endurance.  This is
one of several studies to determine how spaceflight affects muscle
size and strength.

  Thirsk and Favier also participated in the Percutaneous Electrical
Muscle Stimulation investigation.  The experiment requires attachment
of electrodes to the left leg -- a means of applying precise
electrical stimuli to muscles to cause involuntary muscle
contractions. The study will help researchers determine why muscles
lose strength in a microgravity environment.

  Linnehan and Favier continued tests today in the mission's important
musculoskeletal experiments using the ergometer, a bicycle-like
device. To create and maintain a constant workload, the ergometer has
a large, weighted flywheel surrounded by a braking band to resist the
subject's pedaling. On-orbit results will be compared with pre- and
post-flight data to determine the effects of microgravity on muscle
activity, ability to control muscles, and capacity to secrete growth
hormones.  The test will provide investigators with qualitative
measurements of the stress induced by exercise and may help develop
measures to reduce in-flight muscle atrophy.

  Favier, Thirsk and Linnehan continued experiments today to measure the
effects of microgravity on the pulmonary system during rest and heavy
exercise.

  STS-78 Flight Day 10 Highlights:

 On Saturday, June 29, 1996, 6:00 a.m. CDT, STS-78 MCC Status Report #19
reports: 

  Columbia's astronauts will continue to record data on their bodies'
responses to microgravity as part of the Life & Microgravity Spacelab
mission, concentrating today on inner ear changes and muscular
strength measurements.

  Canadian Payload Specialist Bob Thirsk will have a chance to speak
with students at Maple Grove Education Center in Nova Scotia via the
Shuttle Amateur Radio Experiment, and Mission Specialist Chuck Brady
will talk with students from Anacortes Middle School in Washington
State using the on-board "ham" radio gear.

  The crew was awakened at 1:54 a.m. CDT to the sounds of "Another
Saturday Night," as performed by the all-astronaut Max-Q Band. Payload
Commander Susan Helms plays keyboard for the group.

  Columbia has passed the midway mark of its marathon mission. A
decision by mission managers on whether to extend the flight by an
extra day for science is expected by the start of next week. If the
flight is extended, Columbia's mission would end July 7 at Kennedy
Space Center in Florida.

  Flight controllers are not working any significant problems aboard
Columbia, which is providing a stable platform for the ongoing
laboratory reasearch.

 On Saturday, June 29, 1996, 1:00 p.m. CDT, STS-78 Payload Status Report #10
reports: (MET 009/03:00:00)

  Space Shuttle Columbia got a "Go!" in the name of science today --
formal approval by managers to extend the mission by one day, easily
putting this flight on track to become the longest Shuttle flight to
date.

  The science team at the Marshall Space Flight Center in Huntsville,
Ala., had requested the extension to allow an additional day to
conduct a flight manifest loaded with more than 40 experiments in life
and microgravity sciences from an international mix of researchers.

  That approval came at 8:24 a.m. CDT today.  The announcement was sent
up to the crew coupled with a few bars from the movie theme "Mission
Impossible."  The seven-member crew reacted with obvious jubilation,
thrusting their arms into the air and greeting one another with
high-fives.  Said Columbia Commander Tom Henricks: "We are willing,
able and eagerly anticipating" the flight extension.

  The extension will be inserted into the flight timeline on Monday,
adding 24 hours of experiments and activities to the mission.  On
Tuesday, the remainder of the flight schedule, as planned before the
mission, will resume.  For the crew and researchers stationed around
the globe, the extension means more work -- but of the type everyone
is clearly ready and eager to do. Most importantly, it means
substantial benefits to science.

  In the one-day add-on, more tests will be performed and information
gathered from experiments designed to understand the subtle influences
at work during processing of various samples, such as alloy materials,
when gravity's effects are greatly reduced. It means, as well,
additional study into the responses of living organisms and
musculoskeletal physiology to weightlessness.

  Columbia, launched June 20, is completing its 10th flight day
today. If all continues to go well, it will exceed the previous
Shuttle flight-duration record by 7 hours, landing at Kennedy Space
Center on Sunday, July 7 at 7:38 a.m. CDT.

  Space Shuttle Endeavour's Astro 2 mission now holds the endurance
record for its flight in March 1995, of 16 days, 15 hours and 9
minutes. Columbia is set to pass that record on July 7 at 12:58
a.m. CDT.

  Columbia and its orbiting laboratory Spacelab continue to perform in a
nearly flawless fashion today.  Henricks and Shuttle Pilot Kevin
Kregel initiated a study earlier today in the Bubble, Drop, and
Particle Unit.  Designed by Dr. Johannes Straub of Technical
University in Munich, Germany, the study uses small heaters of
different shapes and sizes to examine heat transfer during boiling.
Because boiling is an efficient way to exchange heat, it is used in
many energy conversion systems on Earth. Systems which may benefit
from research in this field include cooling of high-powered electronic
devices, such as computer chips.

  The Bubble, Drop and Particle Unit is working at full capacity today
following successful maintenance procedures Friday to bypass a short
in the unit's power supply. The Electrohydrodynamics of Liquid Bridges
experiment concluded this morning in the Bubble Unit. The study,
developed by Dr.  Dudley Saville of Princeton University, Princeton,
N.J., examined shape changes which occur in a fluid bridge suspended
between two electrodes.  This research may find application in
industrial processes where control of a liquid column or spray is
used. Those include ink-jet printing and polymer fiber spinning.

  In another microgravity sciences investigation, processing continued
today of an aluminum-copper mixture being solidified in the Advanced
Gradient Heating Facility.  In this experiment, designed by Dr. Denis
Camel of the French Atomic Energy Commission in Grenoble, France, one
sample is solidified at a nearly constant temperature, while the other
is processed at a high temperature gradient.  The samples' structure
then will be compared with those of theoretical models.  This research
may lead to better understanding the influence of natural fluid flows
in Earth-based metal alloy processing.  Aluminum alloys are important
in a wide array of applications, such as in manufacturing of
high-performance aircraft components.

  Later today, a cartridge is slated to be inserted into the
high-temperature furnace to begin a study of the segregation of
ternary, or three-component compounds, during solidification. As a
metal alloy or semiconductor crystal solidifies, fluid flows and the
movement of the solid's growing edge can cause the material's
ingredients to separate, forming an uneven sample.  In this
experiment, a compound of gallium, indium and antimony is melted and
resolidified to study the uniformity of the compound's structure.  The
goal of this research is to improve both production methods and final
products of Earth-based industries.  The principal investigator of the
experiment is Dr. Thierry Duffar of the French Atomic Energy
Commission in Grenoble, France.

  A number of experiments are continuing today in the study of life
sciences onboard Columbia.

  Mission Specialists Dr. Richard Linnehan and Dr. Charles Brady and
Payload Specialists Dr. Jean-Jacques Favier and Dr.  Robert Thirsk
participated in a series of tests aimed at measuring muscle strength,
energy expenditure and fatigue.  Using the Torque Velocity Dynamometer
to measure the turning effect on muscles when force is applied, the
four crew members performed arm tests.  One of the experiment's
principal investigators, Dr. Pietro di Prampero of the University of
Udine in Udine, Italy, said today that "analyses so far have shown
smaller changes in the maximal force of leg and arm muscles than
expected." Prampero added: "Researchers are very anxious to see how
the study will progress over the next 10 days."

  Today, the crew completed another of four tests focusing on the
effects of microgravity on the vestibular system in the inner ear. In
space, the vestibular system sometimes becomes confused as to which
way is up and down, leading to nausea and disorientation.  Using
specially designed head gear to monitor head movement and eye
coordination, crew members Linnehan, Brady, Favier, Thirsk and Payload
Commander Susan Helms performed tests throughout their shifts to
determine how the head and eyes track visual and motion targets in
microgravity.  The study, developed by Dr. Millard Reschke of Johnson
Space Center's Medical Sciences Division, is providing scientists with
important information about the crews' ability to adapt to
microgravity.

  Using a laptop computer at the Performance Assessment Work Station,
Favier, Thirsk, Kregel and Henricks today completed a series of tasks
to test thinking skills. The study is designed to help optimize a
crew's work schedule and maximize productivity in space.

 On Saturday, June 29, 1996, 6:00 p.m. CDT, STS-78 MCC Status Report #20
reports: 

  Columbia's crew today performed orbital high-fives when told of the
decision to extend the mission by one day to allow for additional
science data gathering.

  The call to the STS-78 crew came at 8:24 this morning from Astronaut
Chris Hadfield in Mission Control while the payload crew worked on
many of the 40 experiments that make up the Life and Microgravity
Spacelab mission.  Columbia's twentieth space flight is now likely to
break the Space Shuttle endurance record.

  Endeavour currently holds that mark on the STS-67 mission which flew
in March 1995.  That flight lasted 16 days, 15 hours.  The current
mission is now planned to last 16 days, 21 hours.  The record will be
broken as the crew prepares for reentry in the early morning hours of
July 7.

  The anticipated extension of the mission was based on acceptable
margins of electricity to power experiments for the added day and the
performance of Columbia as a platform for the laboratory work in the
Spacelab module.

  The seven-member crew has been adjusting its sleep and wake schedule
gradually throughout the flight to accommodate the early morning
landing at the Kennedy Space Center a week from now.  The astronauts
began an eight hour sleep period at about 5:30 this afternoon and will
receive the traditional wakeup call from Mission Control at 1:29
Sunday morning to begin flight day 12.

  Tomorrow morning beginning at 9:39, the crew will hold a press
conference to discuss the progress of the mission, its objectives and
the scientific investigations underway.

  Columbia's current orbit is circular at 168 statute miles, circling
the Earth every 90 minutes.

  STS-78 Flight Day 11 Highlights:

 On Sunday, June 30, 1996, 7:30 a.m. CDT, STS-78 MCC Status Report #21
reports: 

  Columbia's laboratory research is continuing smoothly, and the crew
will have a half-day off duty this afternoon, the second and final
such half-day break for the astronauts.

  The astronauts will also conduct a news conference at 9:39 a.m. CDT to
discuss the progress of the international mission with media from the
United States, Canada and Europe.

  The crew was awakened for an eleventh day in orbit at 1:29 a.m. to the
sounds of "Les Murs De Poussiere" ("Dusty Walls"), as performed by
French entertainer Francis Cabrel, in honor of French Payload
Specialist Jean-Jacques Favier.

  Columbia continues to operate flawlessly 168 statute miles above the
Earth, providing a stable platform for the ongoing scientific research
in the Spacelab science module. Shuttle managers have extended the
mission by one day to allow time for additional research work, and
landing is now planned for July 7 at the Kennedy Space Center. An
on-time landing would make STS-78 the longest shuttle flight ever,
surpassing the previous shuttle mission duration record by about seven
hours.

 On Sunday, June 30, 1996, 12:00 p.m. CDT, STS-78 Payload Status Report #11
reports: (MET 010/02:11:00)

  The crew of the Space Shuttle Columbia took an opportunity during a
30-minute news conference today to send out its prayers and sympathies
to the families and friends of the U.S. servicemembers killed and
injured in the bombing of the military dormitory in Saudi Arabia last
week.

  Mission Commander Tom Henricks, an astronaut and Air Force colonel,
passed along the crew's sentiments as he and fellow crew members
fielded questions from reporters at NASA locations across the United
States and press rooms in France and Canada.

  During the press conference which began at 9:39 a.m. CDT, the crew
also explained the relevance of the experiments conducted aboard the
Life Sciences and Microgravity mission, and praised support crews and
researchers on Earth who are involved in the mission.  Payload
Specialist Dr. Robert Thirsk told Canadian journalists of how the
research will not only benefit astronauts as they conduct long-term
space missions, but also people on Earth.  Some of the research will
aid studies on osteoporosis and the affects steroids have on bones,
and also may help doctors on Earth develop treatments for muscle
diseases like muscular dystrophy, Thirsk told reporters in Toronto.
"The findings will make a contribution to a further understanding,
countermeasures and rehabilitative programs for not only astronauts
but also for people in hospitals on Earth," Thirsk said.

  Joking with reporters that he and fellow "spaceflight rookies"
Dr. Charles Brady, Dr. Jean-Jacques Favier and Thirsk "were the
experiments," Mission Specialist Richard Linnehan also told reporters
this mission marked the first time such extensive studies of bone and
muscle loss in space have been done.  "With the information we can
figure better ways to keep people in space healthier and fight off
muscle and bone degeneration, and also use the information on Earth,"
he said.

  Pilot Kevin Kregel also praised the video teleconferencing system
being used for the first time on a Shuttle mission.  "The video
conferencing has really been outstanding," Kregel said.  "We used it
to fix the Bubble, Drop and Particle Unit experiment, and it made
fixes a lot easier as opposed to sending up the message and trying to
interpret the fix on paper."  Kregel also made mention of the video
system's morale-boosting properties, especially with regard to the
family teleconferences scheduled throughout the mission.

  Once the press conference was complete, the crew took its second half
day off during the mission.  Crew members used the about 4 1/2-hour
break to relax and complete their second series of 15-minute private
video conference calls with their families since the mission
began. The half-day breaks have been deliberately scheduled throughout
the mission to help the crew maintain a high level of productivity.
In fact, information from the on-going physiology and mental fatigue
studies crew members have been conducting will seek to validate or
possibly adapt later space mission work schedules for peak
performance.

  In other microgravity experiments, this morning Favier and Payload
Commander Susan Helms harvested four of the 20 Loblolly pine seedlings
flown aboard the Shuttle and placed them into a chemical fixative
while the procedure was photographed and recorded on video for
researchers on Earth.  The fixative halted the seedlings' growth to
capture their composition in a moment in time.

  Earlier in the mission the seedlings were bent to a 90- degree angle
and placed in the Plant Growth Facility. The seedling experiment
studies the effect of microgravity on the formation of reaction wood,
which forms when trees growing on Earth bend and then gradually
straighten. Plans call for the crew members to place four more
seedlings into the fixative in two to four days, while the remaining
12 seedlings will be allowed to grow throughout the mission's
duration.

  Mission Specialist Dr. Richard Linnehan performed modifications to the
shoulder straps on the respitrace suit today to adjust its fit for all
crew members.  The suit, worn when crew members participate in the
Astronaut Lung Function Experiment, is a vest-like garment equipped
with electrodes that help monitor rib cage and chest motions during
breathing.  The suit has not fit comfortably on all crew members
during the mission, prompting engineers on the ground to develop the
modification which was sent in message format to the crew early this
morning.

  Earlier today, Pilot Kevin Kregel removed the Straub experiment from
the Bubble, Drop and Particle Unit. Designed by Dr. Johannes Straub of
the Technical University in Munich, Germany, the study used small
heaters of different shapes and sizes to examine heat transfer as a
liquid refrigerant approached the boiling point. This heat transfer
research, which also was conducted on the Shuttle in 1994, will help
with the design of energy conservation systems, including cooling
systems used with high-powered electronic devices such as computer
chips.

  After removing the Straub experiment, Kregel and Shuttle Commander Tom
Henricks placed the second of two experiments developed by Dr. Dudley
Saville of Princeton University, Princeton, N.J., into the Bubble,
Drop and Particle Unit.  The first experiment was completed Saturday.
Both experiments examine the shape changes which occur in a fluid
bridge suspended between two electrodes. The research may find
application in industrial processes where control of a liquid column
or spray is important, such as with ink-jet printing or polymer fiber
spinning.

  Even though the crew members took time off this afternoon from their
busy schedule, many Life Science and Microgravity experiments will
continue this afternoon and overnight, controlled and tracked by
researchers at the Marshall Space Flight Center and at primary
investigation sites in Europe.

  An experiment studying the formation of a ternary, or three-
component, compound as alloys are melted and then solidified will
continue in the Advanced Gradient Heating Facility.  The second
Saville experiment in the Bubble, Drop and Particle Unit will also run
throughout the day as ground-based researchers manipulate the fluid
columns.  Finally protein crystals continue to grow unattended, and
the nearby Microgravity Measurement Assembly continues to measure the
surrounding microgravity environment in the Spacelab module.

  Crew members will be awakened at a little after 1 a.m. CDT Monday to
resume the home stretch of their record-breaking scientific mission.
Columbia is scheduled to land at the Kennedy Space Center one week
from today.

 On Sunday, June 30, 1996, 5:30 p.m. CDT, STS-78 MCC Status Report #22
reports: 

  Work in the Spacelab module this morning and a well deserved half-day
off for Columbia's astronauts in the afternoon, brought to a close the
eleventh flight day of the STS-78 mission.  The day was divided by the
traditional crew news conference this morning in which all seven
astronauts participated.

  Routinely during long-duration Space Shuttle flights crew members are
given two half days off to relax away from the science work ongoing in
the Spacelab.  Telescience -- or remotely operated experimentation
from the ground -- continued, however, while the crew rested today.

  The crew was asked about various aspects of the mission by reporters
during the news conference that began at 9:39 this morning.  News
media from the U.S., Canada and France asked about fatigue, life in a
laboratory environment during long periods and whether there were
noticeable changes in their bodies thus far in the mission.

  Late this afternoon, crew members sent a short video clip to the
ground of the full moon as seen from orbit.  Tonight marks the second
full moon of the month, commonly called a 'blue moon.'
Simultaneously with the downlink video, Mission Control uplinked the
song 'Blue Moon' by The Marcels.

  The crew began an eight hour sleep period at 5:04 this afternoon and
is scheduled to be awakened by Mission Control at 1:04 Monday morning
to begin the twelfth flight day of what is now planned to be the
longest Shuttle mission to date.

  No systems problems aboard Columbia means the orbiter is continuing to
provide a stable platform for the science investigations that continue
in the Spacelab even as the crew sleeps.  At an altitude of 167 miles,
the spacecraft is circling the Earth every 90 minutes providing the
crew with views of an orbital sunrise and sunset 16 times each day.

  STS-78 Flight Day 12 Highlights:

 On Monday, July 1, 1996, 6:00 a.m. CDT, STS-78 MCC Status Report #23
reports: 

  "Canada Day" is being observed on the Space Shuttle Columbia today as
Canadian Payload Specialist Bob Thirsk and his six crewmates spend
their 12th day in orbit on the Life and Microgravity Spacelab mission.

  The STS-78 crew was awakened just after 1 a.m. CDT by the Canadian
national anthem "Oh Canada" as performed by the Vienna State Opera
Orchestra. This morning, Thirsk is scheduled to deliver a holiday
message to Prime Minister Jean Chretien and other dignitaries gathered
at Parliament Hill in Ottawa.

  Also this morning, Mission Specialist Susan Helms will discuss the
progress of Columbia's flight with WBBM Radio in Chicago in an
audio-only interview.

  Columbia continues to operate flawlessly, circling the Earth once
every 90 minutes at an altitude of 168 statute miles.

 On Monday, July 1, 1996, 4:00 p.m. CDT, STS-78 Payload Status Report #12
reports: (MET 011/06:10:00)

  Sunday's half-day off for the Columbia Crew was a brief interlude to
the third and final set of intensive life science experiment runs
scheduled for the Life and Microgravity Spacelab Mission.  Researchers
will compare the crew's test results taken at intervals before, during
and after the mission to study the effects of weightlessness on the
human body.

  The crew -- Pilot Kevin Kregel, Payload Commander Susan Helms, Mission
Specialists Dr. Charles Brady and Dr. Richard Linnehan and Payload
Specialists Dr. Robert Thirsk and Dr.  Jean-Jacques Favier --
continued experiments today to measure the effects of microgravity on
the pulmonary system during rest, heavy exercise and deep
breathing. During the Astronaut Lung Function Experiment, three
electrodes monitor heart activity while the vest-like Respitrace Suit
monitors rib cage and chest motions. The suit was modified Saturday to
accommodate for the lengthening of the spine that crew members have
experienced during the mission. Helms reported this morning that the
suit seems to be working better after the adjustment was made to
lengthen the suit's shoulder straps.

  Wearing head and torso sensors, Linnehan and Thirsk resumed the
Torso Rotation Experiment to determine how eye, head and body
coordination is changed by longer stays in space. Today's test began
the third and final stage of the experiment. Results could help
researchers identify causes of motion sickness during spaceflight,
develop counter measures and lead to practical ways on Earth to avoid
motion sickness in cars, boats, or aircraft.

  In another life science experiment, Linnehan, Brady, Favier and
Thirsk used the Torque Velocity Dynamometer to perform hand-grip
strength tests. The four crew members have been participating in a
series of tests which measure how spaceflight affects muscle strength,
energy expenditure and fatigue.

  Commander Tom Henricks, Kregel, Thirsk and Favier continued an
experiment which studies the effects of spaceflight on thought
processes and mental reaction.  Today the crew members participated in
tests which show the speed and accuracy of their responses to rotated
letters, math problems, letter sequences and rotated images.  Results
of this study may be used to plan future crew schedules, taking
advantage of periods of peak mental performance.

  In the microgravity research area, processing of a three-component
sample in the Effects of Convection experiment led by Dr. Thierry
Duffar of the French Atomic Energy Commission at Grenoble, France,
concluded today in the Advanced Gradient Heating Facility.  Knowledge
from this experiment may help manufacturers produce higher quality
metal alloys and semiconductor crystals.

  After the Effects of Convection experiment concluded, Brady and
Favier inserted a cartridge into the high- temperature furnace,
beginning the Interactive Response of Advancing Phase Boundaries to
Particles experiment. Designed by Ulrike Hecht of the Aachen Center
for Solidification in Space in Aachen, Germany, this experiment
investigates the effects of solidification conditions on the spread of
particles in a sample as it crystallizes. The study focuses on the
different shapes that form on the boundary of the solid region of the
sample and how the development of these shapes is affected as the
boundary contacts floating particles.  Researchers hope to understand
the interaction between free-floating particles and the growing edge
of a solidifying material.  This information will help verify
theoretical models used to develop materials and design better
industrial processes.

  Kregel and Henricks removed the second of two experiments developed
by Dr. Dudley Saville of Princeton University, in Princeton, N.J.,
from the Bubble, Drop and Particle Unit.  The experiment examined the
shape changes which occur in a fluid bridge suspended between two
electrodes, as the voltage is varied. The research may find
application in industrial processes where control of a liquid column
or spray is important, such as with ink-jet printing or polymer fiber
spinning.

  Later, Favier and Brady began the Bubbles and Drops Interaction with
Solidification Fronts experiment in the bubble facility.  A solid
tetracosane test sample was implanted with gas bubbles and then melted
at a low temperature.  Once completely melted and transparent, the
sample was cooled and solidified.  The experiment, designed by
Dr. Rodolfo Monti of University of Naples, investigates the
interaction between the moving pre-formed bubbles and the melting and
solidifying edge.  Researchers hope to learn how to prevent flaws
caused by gases occurring in glass and crystal as they solidify.

  The onboard phase of the Medaka fish experiment concluded on Friday,
and today the crew prepared the experiment's facility for Sunday's
scheduled landing.  Investigators on Earth will study the Medaka fish
embryos which have been preserved, testing a hypothesis that gravity
is required for normal embryo development.  As humans undertake longer
duration spaceflights, understanding the impact of microgravity on
vertebrate development becomes increasingly important.

 On Monday, July 1, 1996, 6:00 p.m. CDT, STS-78 MCC Status Report #24
reports: 

  Columbia's crew went back to work full time today following
yesterday's half-day off.  In addition to the continued science
investigations in the Spacelab module, a couple of crew members took
part in two events to discuss the progress of the mission and to
recognize a holiday.

  Susan Helms, payload commander and flight engineer throughout the
mission, was interviewed this morning by Chicago radio station WBBM
and talked about the myriad of life and microgravity science
investigations that make up the STS-78 mission.  She compared life in
space to that on Earth and explained the reasons for conducting
extensive research into why the human body behaves the way it does in
space and how understanding that behavior can assist people on Earth.

  Also today, Canadian Payload Specialist Bob Thirsk recognized the
129th birthday of his country.  July first marks `Canada Day' and
Thirsk sent greetings in honor of the occasion.

  The astronauts' sleep shift continues to move slightly earlier each
day to condition them for the late night wakeup call on landing day,
now scheduled for Sunday, July 7.  Today the crew went to sleep at
4:39 and will be awakened just after midnight -- at 12:39 Tuesday
morning.

  Columbia continues to operate trouble-free, circling the Earth once
every 90 minutes at an altitude of 168 statute miles.

  STS-78 Flight Day 13 Highlights:

 On Tuesday, July 2, 1996, 6:00 a.m. CDT, STS-78 MCC Status Report #25
reports: 

  Another day of scientific investigations is under way on board
Columbia as the Life and Microgravity Spacelab mission enters its 13th
day in orbit.

  Today, the seven crew members will continue supporting a variety of
experiments investigating the effects of microgravity on the human
body.  Studies looking at muscle strength and energy expenditure and
astronaut pulmonary function will continue throughout the day, as will
the processing of advanced semiconductor materials and alloys in the
Advanced Gradient Heating Facility.

  In an interview this morning with the NBC Newschannel, Mission
Commander Tom Henricks discussed Columbia's flight and the varied
experiments which are being conducted on board.  Henricks explained
that the crew is shifting its scheduled sleep period 25 minutes
earlier with each day, in part to support an early morning wakeup call
on landing day, but also as an investigation into circadian rhythms
and their effect on crew performance.  Crew members participate in
tests which measure their performance on duty, and instrumentation
worn while the crew is asleep gages the quality of sleep for the crew
members.

  Flight Day 13 began with a wake-up call from Mission Control at 12:30
a.m. Central time today.  The crew awoke to "Closer to Free" by the
Bodines.

  Columbia continues to operate trouble-free as it circles the Earth
once every 90 minutes at an altitude of 168 statute miles.

 On Tuesday, July 2, 1996, 3:00 p.m. CDT, STS-78 Payload Status Report #13
reports: (MET 012/05:11:00)

  Four Shuttle crew members today began the second of two key 72-hour
periods of the Sleep and Circadian Rhythms Study.

  Mission Specialists Dr. Richard Linnehan and Dr. Charles Brady, and
Payload Specialists Dr. Jean-Jacques Favier and Dr. Robert Thirsk are
participating in this investigation which is the first-ever
comprehensive study of sleep, 24-hour circadian rhythms and task
performance in a microgravity environment.  Crew members complete
questionnaires before each meal, just after waking, and at the end of
their shift to help monitor their alertness and mood.  Just before
going to sleep, they also put on sleep caps with electrodes that will
help measure brain waves, eye movements and muscle activity while they
sleep.

  Researchers will compare information gathered during the current
72-hour period with information from the first period held June 22-24
to create a picture of how the crews' sleep patterns changed over the
duration of the mission.  The study's principal investigator,
Dr. Timothy Monk of the University of Pittsburgh, said the
investigation is essential to future space missions.  "If we are
really going to do long-term exploration in space, we have to know
what happens when we remove ourselves from real-time cues," Monk said.
The sleep study may also help people on Earth who undergo shift
changes at work or who suffer from jet lag.  Results of the study may
also help researchers better understand sleep patterns.

  Earlier today crew members resumed musculoskeletal experiments on
the Torque Velocity Dynamometer -- a device similar to exercise
equipment found in a gym. The study is intended to determine how
spaceflight affects muscle size and strength. With sensors monitoring
muscle activity, they performed exercises with their right legs as
measurements were made of their muscle strength, power and endurance.
Mission Commander Tom Henricks, Pilot Kevin Kregel, Thirsk and Favier
today resumed tests on the Performance Assessment Work Station, which
is used to determine the effects of microgravity on thinking skills
and mental reaction over the duration of the mission. By comparing
information from the flight and from the later tests performed on the
ground, the investigators may be able to quantify the effects of
spaceflight on each of the mental skills measured. In the future, this
information may be used to optimize work schedules in space.  The goal
is to maximize each crew member's productivity and job satisfaction
during extended missions.

  In the area of microgravity research, Payload Commander Susan Helms
and Thirsk placed an experiment into the Advanced Gradient Heating
Facility that measures the speed at which a mix of pure aluminum and
an aluminum-nickel alloy must solidify to engulf rather than push away
zirconia particles.  The study examines aspects of processing alloys
in a microgravity environment that may improve the processing of
alloys on Earth.

  After the experiment was placed into the high-tech furnace this
afternoon, investigators at Marshall discovered that the heating
facility was not providing data readouts.  Ground controllers
instructed Payload Commander Susan Helms to power down the heating
facility, and after about 30 minutes, it was turned back on and the
flow of data resumed.

  This morning, the first half of the Bubble and Drops Interaction
experiment led by Dr. Rodolfo Monti of the University of Naples,
Italy, was run in the Bubble, Drop and Particle Unit.  This
investigation studies the interaction between moving, pre-formed
bubbles and the melting and solidifying edge of a solid.

  The second part of this experiment, which was scheduled for today,
is designed to examine the way droplets are captured by or pushed away
from a moving solidification front.  The experiment calls for the
injection of water drops of different diameters into an alloy that is
in a liquid state to study drop behavior as heat is applied.  However,
difficulties encountered with the injector prompted the crew to
instead place a boiling experiment originally scheduled for Wednesday
into the Bubble, Drop and Particle Unit.

  The experiment, designed by Dr. Johannes Straub of the Technical
University in Munich, Germany, looks at heat transfer during
boiling. Because boiling is an efficient way to exchange heat, it is
used in many energy conversion systems on Earth. Systems which may
benefit from research in this field include cooling systems for
high-powered electronic devices, such as computer chips.  The same
experiment had a similar run on Sunday.

 On Tuesday, July 2, 1996, 6:00 p.m. CDT, STS-78 MCC Status Report #26
reports: 

  The thirteenth flight day of Columbia's STS-78 mission came to a close
earlier this afternoon following another busy day of science
investigations in the Spacelab module housed in the orbiter's payload
bay.

  The seven astronauts worked with a variety of experiments
investigating the effects of microgravity on the human body.  Studies
of muscle strength and energy expenditure as well as astronaut
pulmonary function continued throughout the day, while processing of
advanced semiconductor materials and alloys in the Advanced Gradient
Heating Facility proceeded uninterrupted.

  Mission Commander Tom Henricks talked about Columbia's flight with the
NBC News Channel early this morning discussing the experiments being
conducted on board.  Henricks explained that the crew is shifting its
scheduled sleep period 25 minutes earlier each day, in part to support
an early morning wakeup call on landing day, but also as an
investigation into circadian rhythms and their effect on crew
performance.

  With that shifting sleep schedule, the astronauts are now scheduled to
be awakened by Mission Control shortly after midnight central time --
at 12:14 a.m.

  Columbia continues to operate trouble-free as it circles the Earth
once every 90 minutes at an altitude of 168 statute miles.

  STS-78 Flight Day 14 Highlights:

 On Wednesday, July 3, 1996, 6:00 a.m. CDT, STS-78 MCC Status Report #27
reports: 

  Columbia's astronauts have begun another day of life and microgravity
science following an early morning wake-up call from Mission Control.

  Four of the crew members -- Mission Specialists Rick Linnehan and
Chuck Brady, and Payload Specialists Jean-Jacques Favier and Bob
Thirsk -- are participating in the second of two integrated 72-hour
studies of sleep cycles, circadian rhythms and crew performance.
Investigators for this study, which began yesterday, will be
monitoring crew alertness and mood through a series of questionnaires
the astronauts will complete over the next 48 hours.  The astronauts
also will don instrumented sleeping caps that will allow investigators
to monitor the quality of crew sleep.

  Columbia's seven astronauts also will work with a variety of
experiments investigating the effects of microgravity on the human
body.  Studies of muscle strength and energy expenditure as well as
astronaut pulmonary function will continue throughout the day, while
processing of advanced semiconductor materials and alloys in the
Advanced Gradient Heating Facility proceed.

  In addition to the ongoing science activities in the Spacelab module,
the crew will take time to discuss their mission in a series of
interviews today.  Shortly after 8 a.m. Central time, Favier and
Mission Commander Tom Henricks will take a call from French Prime
Minister Alain Juppe.  About two hours later, at 10:10 a.m. Central
time, some of Columbia's crew will contact the Mir Space Station crew
-- Commander Yuri Onufrienko, Flight Engineer Yuri Usachev and
Cosmonaut Researcher Shannon Lucid.  The two crews will discuss the
international nature of their flights and the upcoming Olympic Games
with Mr. Billy Payne, President and Chief Executive Officer, Atlanta
Committee for the Olympic Games.

  In the afternoon, Henricks and Thirsk, a Canadian Space Agency
astronaut, will answer questions from students at three different
locations in Canada.  That interactive educational event is scheduled
for 12:14 p.m. Central time.

  The crew awoke this morning to the tune "Wake Up Little Susie" by the
Everly Brothers.  They will go to sleep at 3:49 p.m. Central time
today.

 On Wednesday, July 3, 1996, 6:00 p.m. CDT, STS-78 MCC Status Report #28
reports:

  Columbia's Life and Microgravity Spacelab moved into the homestretch
as the seven astronauts near completion of two weeks in orbit on what
is expected to be the longest Space Shuttle mission to date.

  The crew went to sleep just before 4 p.m. and was scheduled to be
awakened at 11:49 tonight to begin the fifteenth flight day of the
mission.

  About an hour into the sleep period, a switch on the middeck was
inadvertently bumped sounding an alarm on board.  Commander Tom
Henricks reset the switch and went back to bed.

  The crew completed all of its in-flight special events Wednesday,
including a conversation with two cosmonauts and fellow astronaut
Shannon Lucid on Russia's Space Station Mir.  The conversation also
included congratulatory words to both crews from Billy Payne with the
Atlanta Olympic Organizing Committee.  The olympics begin July 19.

  Tomorrow the crew will continue work in the Spacelab module and also
celebrate Independence Day for the United States.  On Monday the crew
celebrated Canada Day in honor of Payload Specialist Bob Thirsk and
his country's 129th birthday.

 On Wednesday, July 3, 1996, 3:00 p.m. CDT, STS-78 Payload Status Report #14
reports: (MET 013/05:11)

  As the Life and Microgravity Spacelab mission today entered the home
stretch for Sunday's landing, crew members continue their work on
musculoskeletal experiments using the Torque Velocity Dynamometer, and
completed their work on the experiment in the Plant Growth Facility.

  Mission Specialists Dr. Richard Linnehan and Dr. Charles Brady, and
Payload Specialist Dr. Robert Thirsk performed muscle strength, power
and endurance tests conducted in the Spacelab using the Torque
Velocity Dynamometer. All three performed the tests with their left
legs.  Thirsk also wore electrodes which applied precise electrical
stimuli to his leg muscles to cause involuntary muscle contractions.
The crew members have performed similar experiments on their arms and
legs throughout the flight.  This study is designed in part to
determine why muscles lose strength in a microgravity environment.

  This morning, Payload Specialist Dr. Jean-Jacques Favier and Payload
Commander Susan Helms harvested the four final seedlings from what was
originally a group of 20 in the Plant Growth Facility and placed them
in a fixative to halt their growth. Four other seedlings were
harvested June 30. The remaining 12 seedlings will be allowed to grow
throughout the mission and then harvested after landing. Earlier in
the mission, the seedlings -- a mix of Loblolly pines and Douglas fir
-- were bent to a 90-degree angle to study the effect microgravity has
on the formation of reaction wood, which forms when trees on Earth
bend and then gradually straighten.  Results from the study may help
the lumber and paper industries which must use extra chemical
processes to remove the inferior reaction wood from pulp and other
products.

	Returning to the area of musculoskeletal experiments, Linnehan
and Brady exercised on a stationary bicycle-like device called the
ergometer.  Exercising on the ergometer during the mission not only
helps the crew members maintain cardiovascular conditioning in the
microgravity environment, but it also helps researchers gather data to
determine the effects of microgravity on muscle activity, the ability
to control muscles, and the capacity to secrete growth hormones.
Tests conducted on the ergometer may help scientists develop measures
to reduce in-flight muscle atrophy.  The ergometer also has been used
extensively in the Astronaut Lung Function Experiment, and has served
as a secure seat or base for crew members as they perform the Canal
and Otolith Integration Studies.

	The crew also continued the Astronaut Lung Function
Experiment, which measures the effects of microgravity on the
pulmonary system during rest, heavy exercise and deep breathing.

	Brady, Linnehan, Thirsk and Favier also crossed the half-way
point of the Sleep and Circadian Rhythms study's second 72-hour
period.  The four crew members completed a series of performance and
mood tests displayed on a laptop computer throughout the day to assess
the quality of their sleep and their mental functions.

	Favier also put on head and torso sensors and resumed the
Torso Rotation Experiment. The investigation examines how eye, head
and body coordination changes during long stays in space.  Results
could help researchers identify the causes of motion sickness during
space flight, and also help them develop countermeasures.  Results
could also lead to practical ways on Earth to prevent motion sickness
in cars, boats and aircraft. The principle investigator is Dr. Douglas
Watt of McGill University in Montreal, Canada.

	In the area of microgravity materials, an experiment measuring
the speed at which a mix of pure aluminum and an aluminum-nickel alloy
must solidify to engulf rather than push away zirconia particles
concluded today in the Advanced Gradient Heating Facility.  Pilot
Kevin Kregel and Mission Commander Tom Henricks later inserted the
Coupled Growth in Hypermonotectics Experiment into the high-tech
furnace.  Led by Principle Investigator Dr. Barry Andrews of the
University of Alabama at Birmingham, the experiment processes aluminum
and indium samples to study the segregation of alloys as they
solidify. The study is aimed at developing ways to control the
internal structure of alloys during processing. The research may lead
to the development of new alloys for engineering, chemical and
electronic applications.

	An experiment in the Bubble, Drop and Particle Unit that 
examines heat transfer as a refrigerant is brought to the 
boiling point ran overnight and through this afternoon on 
board Columbia.  Boiling is an efficient way to exchange 
heat, and it is used in many energy conversion systems on 
Earth.  Areas that may benefit from the study include the 
development of cooling systems for high-powered electronic 
devices, such as computer chips.

	This was the second run for the investigation designed 
by Dr. Johannes Straub of the Technical University in Munich, 
Germany.  Straub's experiment was placed in the unit one day 
ahead of schedule after technical problems with a separate 
cartridge Tuesday cut one half of an experiment short.  The 
experiment, designed by Dr. Rodolfo Monti of the University 
of Naples, Italy, first injects bubbles, then water drops, 
into a waxy substance is in a liquid state to study bubble 
and drop behavior as the wax is solidified. However, during 
the water drop phase Tuesday, investigators discovered that 
the injector would not retract from its deployed position, 
prompting the cartridge's removal and the rescheduling of the 
one remaining Straub experiment.  Within an hour and a half 
of discovering the problem, engineers developed a solution in 
the Spacelab mock-up at Marshall, and mission planners expect 
the second half of the Monti experiment will be completed by 
Friday.

  STS-78 Flight Day 15 Highlights:

 On Thursday, July 4, 1996, 6:00 a.m. CDT, STS-78 MCC Status Report #29
reports: 

  Bruce Springsteen's "Born in the USA," and Lee Greenwood's "I'm
Proud to be an American" greeted Columbia's seven astronauts today as
they awoke to begin their fifteenth flight day on orbit.

  Mission Commander Tom Henricks responded to Mission Control's wake
up call by saying that the five US-born crew members were very proud
to be Americans, particularly on the day America celebrates its 220th
anniversary. On Monday, the crew celebrated Canada Day in honor of
Payload Specialist Bob Thirsk and his country's 129th birthday.

  Today, work in the Spacelab module will continue with investigations
into the effects of microgravity on muscle strength and endurance,
astronaut lung function, and adaptation of the neurovestibular system
to a microgravity environment.  Henricks and Pilot Kevin Kregel will
complete work with a laptop computer designed to test the crew's
critical thinking skills and reaction time. They also will test a
voice control system that allows them to reposition Columbia's
closed-circuit television cameras with verbal cues, keeping their
hands free to perform other tasks.

 On Thursday, July 4, 1996, 5:00 p.m. CDT, STS-78 MCC Status Report #30
reports:

   With their sleep shifts now set on a schedule to prepare for
Sunday's planned return to Earth, the astronauts aboard Space Shuttle
Columbia will receive a wakeup call at 11:39 tonight to begin the
sixteenth flight day of the mission.

  Earlier today, Commander Tom Henricks recognized America's
Independence Day by showing a television view of the U.S. from space
with patriotic music playing in the background.  He also paid tribute
to the service personnel killed and injured in the recent bombing in
Saudi Arabia.

  Work in the Spacelab module continued today with investigations into
the effects of microgravity on muscle strength and endurance,
astronaut lung function, and adaptation of the neurovestibular system
to a microgravity environment.  Laboratory work will continue tomorrow
with several of the experiments being wrapped up in preparation for
the return trip home planned for Sunday morning at the Kennedy Space
Center in Florida.

  Henricks and Pilot Kevin Kregel completed work with a laptop
computer designed to test the crew's critical thinking skills and
reaction time.  They also tested a voice control system that
repositions Columbia's closed-circuit television cameras with verbal
cues.  The test showed the feasibility of the experiment to free crew
members' hands for other tasks.

  Columbia's twentieth spaceflight enters the last three days with no
orbiter problems being tracked by Mission Control.  The spacecraft is
circling the Earth every 90 minutes at an altitude of 168 statute
miles.

 On Thursday, July 4, 1996, 12:00 p.m. CDT, STS-78 Payload Status Report #15
reports: (MET 014/02:11)

  There were no fireworks, just a normal busy day of experiments for
the crew of the Space Shuttle Columbia as it crossed the two-week
point this Independence Day on the way to completing its
record-setting 17-day mission.  However, right after lunch crew
members did take an opportunity to play a few patriotic songs and wish
Americans on Earth a happy Fourth of July.

  It was evident to all that the closing days of the mission were at
hand as the crew members prepared to run a final planned experiment
through the Bubble, Drop and Particle Unit, and investigators on the
ground monitored the processing of a final planned experiment in the
Advanced Gradient Heating Facility.

  Pilot Kevin Kregel and Payload Commander Susan Helms successfully
performed an in-flight maintenance procedure on the Bubbles and Drops
Interaction with Solidification Fronts experiment cartridge and
inserted it into the Bubble, Drop and Particle Unit.

  Designed by Dr. Rodolfo Monti of the University of Naples, Italy,
the experiment first examines the interaction of gas bubbles, and then
liquid drops, against the leading edge of a solidifying waxy
substance.  The first half of the study focusing on bubbles was
successfully completed Tuesday.  The second half focusing on drops was
to have run immediately after the first; however, during the water
drop phase, investigators discovered a water injector would not
retract from its deployed position, prompting the cartridge's
removal. Engineers on the ground quickly developed a solution to what
was determined to be a minor electrical problem, and the crew members
completed the procedure without a hitch this morning.  Results of the
Monti experiment -- the final of 14 carried out as planned throughout
the flight -- may help researchers learn how to prevent flaws created
by gasses released as glass and crystal solidify.

  Before performing the scheduled in-flight maintenance procedure on
the Bubble, Drop and Particle Unit, Helms and Kregel removed an
experiment led by Dr. Johannes Straub of the Technical University in
Munich, Germany, from the unit.  This investigation -- which began its
second run of the mission Tuesday following the first half of the
Monti experiment -- examined heat transfer as a liquid refrigerant was
brought to the boiling point.  The research could lead to the creation
of cooling systems for small high-powered electronic devices, such as
computer chips.

  An aluminum-indium sample continued to be processed today in the
Advanced Gradient Heating Facility.  The experiment, led by Principle
Investigator Dr. Barry Andrews of the University of Alabama at
Birmingham, studies the segregation of alloys as they solidify.  Its
aim is to help researchers develop ways to control the internal
structure of alloys during processing.

  Today was a busy day for crew members using the Torque Velocity
Dynamometer, a multi-use exercise machine designed to test muscle
strength in various parts of the body.  This morning, Payload
Specialist Dr. Jean-Jacques Favier and Mission Specialist Dr. Richard
Linnehan resumed arm, hand-grip and leg strength tests on the
dynamometer, while Mission Specialist Dr. Charles Brady performed arm
strength tests, and Payload Specialist Dr. Robert Thirsk performed
hand-grip tests. Before the leg strength tests, both Favier and
Linnehan attached electrodes to their left legs which applied precise
electrical stimuli to cause involuntary muscle contractions.

  Thirsk and Favier also exercised on a stationary bicycle-like device
called the ergometer.  Exercising on the ergometer during the mission
not only helps the crew members maintain cardiovascular conditioning
in the microgravity environment, but it also helps researchers gather
data on in- flight muscle atrophy. Information from the various
dynamometer and ergometer operations today may help investigators
determine why muscles lose strength in a microgravity environment.

  Thirsk, Henricks, Favier and Kregel today also continued their tests
on the human behavior workstation, which they've conducted on
alternate days throughout the mission.  A laptop computer displays a
series of problem-solving exercises which help track each crew
members' level of mental fatigue.

  Researchers hope to use the results of the continuing study to plan
future crew schedules that take advantage of periods of peak mental
performance.

  Brady, Favier, Thirsk and Linnehan also brought to a close the final
72-hour period in the Sleep and Circadian Studies. The study looks at
how life in space affects sleep patterns, circadian rhythms and mental
alertness.  The crew members completed questionnaires at the beginning
and end of their day, as well as alertness and mood tests before each
meal and throughout the morning.  A similar 72-hour period was
completed earlier in the flight.

  Helms, Kregel, Thirsk and Favier continued the Astronaut Lung
Function Experiment to measure the effects of microgravity on the
pulmonary system during rest, heavy exercise and deep breathing. All
four crew members wore electrodes to monitor their heart activity, and
all but Helms wore the vest-like Respitrace Suit to monitor chest and
abdomen motions during breathing as they conducted the studies.

  STS-78 Flight Day 16 Highlights:

 On Friday, July 5, 1996, 6:00 a.m. CDT, STS-78 MCC Status Report #31
reports: 

  A bonus day of science is under way on board Columbia as the
astronauts continue their scientific investigations in the Spacelab
module.

  This morning's science activities consisted of experiment sessions
being held in reserve pending the extension of the STS-78
mission. With all orbiter systems performing well and plenty of
electricity available for the additional payload work, last week
mission managers gave crew members and the payload community that
extra day, potentially making Columbia's flight the longest is Space
Shuttle history.

  Work today focuses on how the astronauts' bodies are responding to the
microgravity environment after more than two weeks in orbit.  The
payload crew will support studies into adaptation of the
neurovestibular system and the musculoskeletal system during
spaceflight.  Mission Commander Tom Henricks and Pilot Kevin Kregel
will spend one additional day working with a human behavior
investigation that measures their reaction time to a series of
pre-programmed computer images.

  Columbia's crew will then begin to wrap up operations with many of
the experiments on board in preparation for Sunday morning's planned
return to the Kennedy Space Center in Florida. The crew awoke to
"Birthday" by The Beatles in recognition of Henricks' 44th birthday
today.

  Columbia enters the final days of this record-setting mission with
no orbiter problems being tracked by Mission Control.  The spacecraft
is circling the Earth every 90 minutes at an altitude of 168 statute
miles.

 On Friday, July 5, 1996, 5:00 p.m. CDT, STS-78 MCC Status Report #32
reports:

  Columbia's astronauts completed another full day of laboratory work
aboard the Spacelab today, a day which normally would have been used
to prepare for the spacecraft's return to Earth. But with a mission
extension granted last weekend, the crew could spend the extra time
with the 40-plus life and microgravity experiments.

  Work today focused on how the astronauts' bodies are responding to
the microgravity environment after more than two weeks in orbit.  The
payload crew's work will support studies into adaptation of the
neurovestibular system and the musculoskeletal system during
spaceflight.

  The crew will be awakened at 11:34 tonight central time to begin its
last full day on orbit.  Saturday the crew will prepare for Sunday's
landing by stowing equipment used throughout the mission and shutting
down the laboratory module carried in Columbia's payload bay.  Also
tomorrow, the crew will turn its attention to checking out Columbia's
systems by testing the flight control system and firing all of the
small maneuvering thruster jets to ensure their health and readiness
to support landing.

  Additionally, the crew will test a procedure to subtly boost its
altitude to prove a concept that may be used on Discovery's next
mission -- STS-82 -- to service the Hubble Space Telescope.  The test
has the crew firing the small vernier control jets in a precise
pattern to slightly raise the orbit while not disturbing payloads.  If
adopted, the concept will assist in boosting the telescope's altitude
without having to contract the sensitive solar arrays.

  Columbia's crew will then begin to wrap up the last of experiment
operations in preparation for Sunday morning's planned return to the
Kennedy Space Center in Florida.  Two landing opportunities are
available Sunday. The first is at 7:37 a.m. CDT and the second at 9:11
a.m. Based on the planned landing early Sunday morning, the orbiter
will complete 272 revolutions of the planet.

 On Friday, July 5, 1996, 4:30 p.m. CDT, STS-78 Payload Status Report #16
reports: (MET 015/06:43)

  While the record-setting 17-day mission of the Space Shuttle
Columbia will come to an end Sunday, researchers will use the coming
weeks and months to sift through the wealth of information gathered
from the more than 40 life sciences and microgravity experiments
conducted within the Spacelab capsule.

  The crew began winding down its science activities Friday morning
after what has been an extremely busy Spacelab mission.  Plans call
for the crew to shut down the Spacelab module at about noon CDT
Saturday.  The Shuttle is scheduled to land at 7:37 a.m. CDT Sunday at
the Kennedy Space Center in Florida.  This will eclipse the Shuttle
mission duration record set by Endeavour STS-67 in March 1995 by about
seven hours.

  In fact, the one extra day gained as the mission went from 16 to a
record 17 days allowed the crew members to give some investigators on
Earth extra runs in the Advanced Gradient Heating Facility and in the
Bubble, Drop and Particle Unit, and also help investigators gather
extra information for various life sciences studies.

  "We had 41 principal investigators involved with the mission, and
all but very few have 100 percent, if not 200 percent, of the data
they had hoped to collect during the mission," said Mission Scientist
Dr. J. Patton Downey at Marshall Spacelab Operations Control Center.

  "Overall, in terms of life sciences, the information gathering has
just been tremendous," added Dr. Victor Schneider, the Life and
Microgravity Sciences program scientist with NASA Headquarters.  "As a
scientist, I think the amount of data we will have is exciting."  An
international team of researchers from NASA, the European Space
Agency, and colleges and universities across the

  United States and in Europe monitored and remotely controlled
experiments as the crew helped conduct or process them.  This was the
most extensive use of "remote telescience" in the Shuttle program's
history.  According to Mission Manager Mark Boudreaux, the ability of
investigators to remotely control and monitor experiments from four
remote European and four remote domestic locations is a key aspect of
the upcoming International Space Station era. Thanks to Spacelab,
scientists can plan on using the now-proven technology to manipulate
experiments in space from their own research centers.  In many ways
the space station will serve as a remote space-bound scientific
platform where researchers will remotely control and conduct
experiments around the clock, just as was demonstrated in Spacelab.

  Another vital "first" on this mission was the beaming of video
images to the shuttle to help crew members perform in- flight
maintenance procedures.  Engineers developed solutions to minor
technical difficulties experienced on some of the Spacelab experiments
in the Spacelab mock-up at Marshall, and then beamed video images of
the procedures to the crew members to help them carry out the repairs.

  Equally vital to any future missions and the space station era is
the information gathered from the life sciences experiments that were
conducted aboard Spacelab.  Numerous experiments meant to gather
information on muscle strength, endurance, mental fatigue, muscle
tissue loss and sleep cycles were conducted, and researchers will
compare the results with baseline information gathered while the crew
was on Earth to determine the physiological effects of living in a
microgravity environment.  Investigators will gain insight on how to
develop ways to help astronauts maintain their muscle strength and
endurance not only on future shuttle missions, but also during future
long-term missions on board the space station and perhaps someday on a
mission to Mars.

  Learning how the human body adapts to a microgravity environment is
necessary if astronauts are to conduct future long-term space
missions.

  This mission also marked the first time researchers will collect
muscle tissue biopsy samples from crew members both before and after
the flight. Crew members are to undergo muscle biopsy samples and an
MRI scan almost immediately after they land at the Kennedy Space
Center.  The findings from the comparison of the biopsy samples, along
with the various musculoskeletal tests conducted on the flight, could
help scientists develop measures to reduce in-flight muscle atrophy
and also fight certain muscle diseases and osteoporosis on Earth.

  During the mission, crew members exercised regularly on an ergometer
to not only help them maintain cardiovascular conditioning in the
microgravity environment, but also help researchers gather data to
determine the effects of microgravity on muscle activity, the ability
to control muscles, and the capacity to secrete growth hormones.
Experiments focusing on muscle strength were conducted on the Torque
Velocity Dynamometer, a device which looks somewhat like exercise
equipment found in a gym. The dynamometer provided investigators on
Earth precise measurements of leg, arm and hand-grip strength, power
and endurance.  Some crew members also attached electrodes to their
leg muscles for studies on why muscles lose strength in the
microgravity environment. The electrodes applied precise electrical
stimuli to muscles causing involuntary muscle contractions.

  Metabolic experiments were also conducted as the crew collected
fluid and calcium tracer samples throughout the flight to help
investigators measure bone lose and changes to the metabolism. Crew
members also participated in studies on pulmonary function in
weightlessness.  The Astronaut Lung Function Experiment investigated
effects of spaceflight on the pulmonary system during heavy exercise,
deep breathing and rest.  During the experiment crew members wore
electrodes to monitor heart rhythm and a vest-like suit to monitor
movements of the chest and abdomen. The crew also used the Gas
Analysis System for Metabolic Analysis Physiology to compare inhaled
and exhaled gases.

  Two specific investigations also focused on how living and working
in space affects sleep patterns and mental and physical functions. The
goal of each investigation is to maximize a crew member's productivity
and job satisfaction during extended missions. The scheduling of
future crew work and rest schedules may be refined based on the
knowledge gained on this mission.

  The first investigation involved studying the effects of spaceflight
on thought processes. On alternating days, crew members completed a
battery of tests on the Performance Assessment Work Station.  The
tests tracked the speed and accuracy of their responses to rotated
letters and images, math problems and letter sequences. The results of
this study could help researchers determine levels of mental fatigue
and alertness.

  The second investigation was a comprehensive study of sleep patterns
in space.  The Circadian Rhythm and Sleep Study consisted of two
separate 72-hour test periods, one near the beginning of the flight
and one toward the end.  Crew members completed questionnaires before
each meal, just after waking and at the end of their shifts to help
monitor their alertness and mood.  They also wore sleep caps with
electrodes to measure brain waves, eye movements and muscle activity
while they slept. Results of this study may also benefit people on
Earth by helping people whose sleep schedules suffer from shift
changes or jet lag.

  "These were the first integrated studies where we could look at
mood, Circadian rhythms and sleep," Schneider said.  "We need to know
how we can help individuals in space and on Earth work different
schedules."

  Two neuroscience experiments yielded information on the crew
members' adaptation to the microgravity environment in regard to
balance and spatial orientation, and the part those two factors play
in motion sickness during space travel.  Past experience has shown
that motion sickness can be a problem for some crew members during the
first few hours of a mission.  Crew members, wearing head and torso
sensors, participated in the Torso Rotation Experiment to determine
how eye, head and body coordination changes during longer stays in
space. The experiment yielded results that could help researchers
identify causes of motion sickness during space flight, develop
counter measures, and lead to practical ways on Earth to avoid motion
sickness in cars, boats or aircraft.

  The Canal and Otolith Integration Study examined the effects of
microgravity on the vestibular system of the inner ear and the
resulting changes in eye-hand-head coordination.  During this
investigation, crew members wore high-tech modified ski goggles which
helped record their eye and head movements as they tracked illuminated
targets.

  In the area of microgravity sciences and materials processing, six
individual experiments, some with many separate runs, were conducted
in the Advanced Gradient Heating Facility, a furnace for solidifying
alloys and crystals. These experiments yielded information on the
physical processes involved in solidification, and the results may
help drive the production of advanced semiconductor materials in space
and on Earth.

  The crew also ran more than a dozen fluid physics experiments
through Bubble, Drop and Particle Unit.  The experiments primarily
focused on the interaction of gas bubbles or liquid drops in various
liquids as varying degrees of heat were applied.  Research gathered
from experiments completed in the unit could lead to advances in
material processing on Earth, including the processing of new high-
strength metals and temperature-resistant glasses and ceramics.

  Finally, four experiments ran in the Spacelab module almost
continuously throughout the 17-day mission.  The Advanced Protein
Crystallization Facility is the first facility ever designed to use
three methods of protein crystal growth. By examining the molecular
structure of proteins, medical researcher will gain insight into these
basic building blocks of life. Experiments could improve food
production, as well as lead to innovative new drugs to combat disease.

  In the Plant Growth Facility, researchers bent 20 seedlings to a
90-degree angle and monitored their growth in the microgravity
environment to study the formation of reaction wood. Reaction wood
forms when trees on Earth bend and then gradually straighten. Results
from the study may help the lumber and paper industries which must use
extra chemical processes to remove the inferior reaction wood from
pulp and other products.  Crew members harvested four of the seedlings
-- which were a mix of Loblolly pines and Douglas fir -- June 20, and
then harvested four more July 3, and placed the seedlings in a
fixative to halt their growth.  The remaining 12 seedlings were
allowed to grow through the scheduled landing.

  In a separate experiment, investigators also used video images to
monitor the development of Medaka fish embryos in the microgravity
environment. Since the embryos are transparent, investigators could
easily follow the development of internal organs. Also, groups of the
Medaka embryos were periodically preserved for testing on return to
Earth. The tests will enable investigators to support a hypothesis
that gravity is required for normal embryo development. As humans
undertake even longer duration spaceflights, understanding the impact
of microgravity on vertebrate development becomes increasingly
important.

  Twelve rodents also remained in the Animal Enclosure Module
throughout the Shuttle mission.  The laboratory rodents will be
studied after landing to provide researchers insight into bone mass,
levels of bone formation and bone cell activity in the microgravity
environment.

  STS-78 Flight Day 17 Highlights:

 On Saturday, July 6, 1996, 6:00 a.m. CDT, STS-78 MCC Status Report #33
reports: 

  Columbia's astronauts conducted routine firings of the orbiter's
reaction control system jets and checked out its flight control
systems and aero surfaces this morning in anticipation of Sunday's
planned landing at the Kennedy Space Center.

  Early this morning, Commander Tom Henricks and Pilot Kevin Kregel
successfully fired Columbia's 44 reaction control system jets and then
cycled the aero surfaces that will be used during Columbia's high
speed re-entry Sunday morning.  All of Columbia's systems are healthy
and ready to support tomorrow's landing.

  Just after 3 a.m. Central time today, Henricks and Kregel pulsed
Columbia's vernier reaction control system jets to gently raise
Columbia's altitude.  These firings were part of a test to prove a
concept that may be used on Space Shuttle Discovery's next mission --
STS-82 -- to service the Hubble Space Telescope.  The vernier jet
firings should raise the orbit without disturbing any payloads on
board, or in the case of the Hubble Space Telescope, without placing
any force on the telescope's fragile solar arrays.

  The payload crew --Mission Specialists Susan Helms, Rick Linnehan and
Chuck Brady, and Payload Specialists Jean-Jacques Favier and Bob
Thirsk -- began to wrap up the last of their experiment operations in
the Spacelab module this morning.  About noon today, they will begin
deactivating Spacelab, although the hatch between Columbia and the lab
will not be closed until early Sunday morning.

  There are two landing opportunities available on Sunday, both to the
Kennedy Space Center in Florida. The first opportunity would have
Columbia landing at the Kennedy Space Center at 7:37 a.m. Central time
Sunday, with a second opportunity one orbit later resulting in a
landing at 9:11 a.m. Central time.  If Columbia lands on the initial
opportunity, it will have completed 272 revolutions of the Earth and
traveled about 7 million miles, while setting a new shuttle endurance
record.

  Columbia continues to circle the Earth at an altitude of about 165
statute miles, with all of its systems in readiness to support
Sunday's landing.

<end of mission>