Mission Name: STS-83 (83)
  Columbia (22)         
  Pad 39-A (60)
  83rd Shuttle Mission
  22nd Flight OV-102
  Spacelab(14)

 NOTE: Click Here for Countdown Homepage

Crew:
  James D. Halsell (3), Mission Commander
  Susan L. Still (1), Pilot
  Janice E. Voss (3), Payload Commander
  Donald A. Thomas (3), Mission Specialist
  Michael L. Gernhardt (2), Mission Specialist
  Roger Crouch (1), Payload Specialist
  Greg Linteris (1), Payload Specialist
 
Milestones:
   OPF-1 -- 12/07/96 (Reference KSC Shuttle Status 12/07/1996)  
     VAB -- 03/05/97 (Reference KSC Shuttle Status 3/05/1997)  
     PAD -- 03/11/97 (Reference KSC Shuttle Status 3/11/1997)  
    TCDT -- 03/13/97 (Reference KSC Shuttle Status 3/13/1997)

Payload:
  MSL-1,SAREX

  (Reference KSC Shuttle Status Feb 1997)
  (Reference KSC Shuttle Status Mar 1997)
  (Reference KSC Shuttle Status Apr 1997)

Mission Objectives:
  The primary payload on STS-83 is the Microgravity Science Laboratory
(MSL-1).  MSL-1 is a collection of microgravity experiments housed inside
a European Spacelab Long Module (LM).  It builds on the cooperative and 
scientific foundation of the International Microgravity Laboratory missions
(IML-1 on STS-42 and IML-2 on STS-65), the United States Microgravity Laboratory 
missions (USML-1 on STS-50 and USML-2 on STS-73), the Japanese Spacelab mission 
(Spacelab-J on STS-47), the Spacelab Life and Microgravity Science Mission 
(LMS on STS-78) and the German Spacelab missions (D-1 on STS 61-A and D-2 on STS-55).

  MSL-1 features 19 materials science investigations in 4 major
facilities.  These facilities are the Large Isothermal Furnace, the
EXpedite the PRocessing of Experiments to the Space Station (EXPRESS)
Rack, the Electromagnetic Containerless Processing Facility (TEMPUS)
and the Coarsening in Solid-Liquid Mixtures (CSLM) facility and the
Combustion Module-1 Facility. Additional technology experiments will 
also be performed in the Middeck Glovebox (MGBX) developed by the 
Marshall Space Flight Center (MSFC) and the High-Packed Digital 
Television (HI-PAC DTV) system will be used to provide multi-channel
real-time analog science video.

  The Large Isothermal Furnace was developed by the Japanese Space Agency 
(NASDA) for the STS-47 Spacelab-J mission and was also flown on
STS-65 IML-2 mission. It will house
the Measurement of Diffusion Coefficient by Shear Cell Method Experiment, 
the Diffusion of Liquid Metals and Alloys Experiment, 
the Diffusion in Liquid Led-Tin-Telluride Experiment, 
the Impurity Diffusion in Ionic Melts Experiment, 
the Liquid Phase Sintering II Experiment (LIF), and 
the Diffusion Processes in Molten Semiconductors Experiment (DPIMS).

  The Combustion Module-1 (CM-1) facility from the NASA Lewis Research Center
houses experiments on Laminar Soot Processes Experiment and the Structure of
Flame Balls at Low Lewis-number Experiment (SOFTBALL).

  The EXPRESS rack replaces a Spacelab Double rack and special hardware
will provide the same structural and resource connections the rack will
have on the Space Station.  It will house the Physics of Hard Spheres (PHaSE)
experiment and the Astro/PGBA Experiment.

  The Electromagnetic Containerless Processing Facility (TEMPUS) is used
for the Experiments on Nucleation in Different Flow Regimes,
Thermophysical Properities of Advanced Materials in the Undercooled
Liquid State Experiment, Measurements of the Surface Tension of Liquid
and Undercooled Metallic Alloys by Oscillating Drop Technique
Experiment, Alloy Undercooling Experiments, the Study of the
Morphological Stability of Growing Dendrites by Comparative Dendrite
Velocity Measuremetns on Pure Ni and Dilute Ni-C Alloy in the Earth
and Space Laboratory Experiment, the Undercooled Melts of Alloys with
Polytetrahedral Short-Range Order Experiment, the Thermal Expansion of
Glass Forming Metallic Alloys in the Undercooled State Experiment, the
AC Calorimetry and Thermophysical Properties of Bulk Glass-Forming
Metallic Liquids experiment and the Measurement of Surface Tension and
Viscosity of Undercooled Liquid Metals experiment.

  There will also be experiments on measuring microgravity.  They 
include the Space Acceleration Measurement System (SAMS), 
the Microgravity Measurement Assembly (MMA), 
the Quasi-Steady Acceleration Measurement System and 
the Orbital Acceleration Research Experiment (OARE).

  The Middeck Glovebox (MGBX) facility will support the Bubble and
Drop Nonlinear Dynamics (BDND) Experiment, the Study of the Fundamental
Operation of a Capillary-driven Heat Transfer (CHT) Device in Microgravity
Experiment, the Internal Flows in a Free Drop (IFFD) experiment and
the Fiber Supported Droplet Combustion experiment (FSDC-2).

Launch:
  Launch April 4, 1997 2:20:32.074 pm EST. Launch window was 
2 hours 30 min.  
  
  At 1:32pm EST, the countdown clock came out of the hold at the T-20
minute mark and the OMS/RCS crossfeed valves and MPS Helium system
were configured for flight. The GPC computers were dumped and their
contents verified to be in flight configuration. At 1:41pm EST, the
countdown clock entered the hold at the T-9 minute mark.  The hold at
T-9 minutes will be extended to give the white room crew additional
time to clear the pad due to the need to replace a seal on the crew
hatch and perform the cabin leak test.   At 1:53pm EST the white room
crew cleared the pad.  At 2:05pm EST, the close out crew made it back
to the launch control center area and the launch team was polled to
determine if all stations were ready to come out of the T-9 minute
hold.  All stations except position SPE gave a clear to launch.  The
only concern was an excess concentration of O2 in the shuttle midbody.
The gaseous purge was modified and the concentrations decreased.  At
2:11pm the launch team was polled again and there were no constraints
to launch.  The count picked back up at T-9 minute mark at 2:12pm.
The sound supression water system was armed at 2:20pm at the T-1
minute mark with a T-0 at 2:21pm EST.  SRB seperation at 2:23pm 43
miles east of KSC.  SSME Cutoff at 2:30pm EST with Columbia traveling
at 15,500mph and 720 miles east of KSC.  External Tank separation
occured at 2:30pm EST.

  At the T-3 hour mark, the launch final inspection team was at the
pad doing a final walkdown.  The inspection team is at the launch pad
for about 2 hours and looks for any ice buildup on the external tank
and any debris that could impact the orbiter at liftoff. The white
room crew began their initial preparations with an estimated
hatch closure time of 12:30pm.  The flight crew ate breakfast in 
the crew quarters of the Operations and Checkout Building and at
10:30am EST, they donned their flight suits.  The countdown
clock came out of the T-3 hour hold at 10:40am EST and the
crew departing for Launch Pad 39-A at 10:42am.

  The countdown resumed at 2 a.m. Thursday at the T-19 hour mark
following a 24-hour postponement of launch necessary to add additional
insulation to water coolant lines in the payload bay.  Launch is set
for 2 p.m. EST Friday, April 4, at the opening of a 2 1/2 hour
window. Air Force weather forecasters are currently indicating only a
10 percent probability of weather prohibiting launch of Columbia on
April 4. The only concern is for a slight chance of rain showers
generated by sea breezes.  
(Reference KSC Shuttle Status 4/3/97)

  The countdown began at the T-43 hour mark at 2 pm on Monday, March
31, 1997 with a planned launch date of Thursday, April 3, 1997 at
2:01pm. (Reference KSC Press Release 54-97).  However, the clock was
held at the T-19 Hour mark on Tuesday April 1, 1997 and a new T-0 was
set for Friday, April 4, 1997 at 2:00pm EST.  The Mission Management
Team briefly considered but decided against an option to move the
launch time forward approximately 1 hour to 1:07pm EST.  The move
forward in launch time would have allowed more daylight at the Banjul
TAL site and help with concerns about delamination of a backup antenna
system at Banjul.

  On Tuesday, April 1, 1997 the decision was made to slip the launch
one day, after managers determined that a water coolant line in the
orbiter's payload bay was not properly insulated. Additional
insulation was required to prevent this line from possibly freezing
during Columbia's 16 days in space. 
(Reference KSC Shuttle Status 4/1/97)

  On Tuesday, 3/25/97, the loading of hypergolic propellants into
the orbiters Reaction Control System (RCS) was completed and ordnance
installation conducted. (Reference KSC Shuttle Status 3/25/1997)

  On Thursday, 3/20/97, following completion of the Flight Readiness
Review, NASA managers set April 3, 1997, as the official launch date
for NASA's Microgravity Science Laboratory (MSL-1) mission.  
Donald A. Thomas, who suffered a broken ankle following a routine training
exercise on Jan. 29, has officially been cleared to fly as planned.
(Reference KSC Press Release 49-97)

  On Thursday, 3/13/97, The STS-83 Terminal Countdown Demonstration
Test (TCDT) was conducted at KSC. The TCDT is held prior to each Space
Shuttle flight providing the crew of each mission opportunities to
participate in simulated countdown activities.  Overnight, inspections
were made of the low pressure fuel turbo pumps on the three Space
Shuttle main engines. The pump on engine No. 1 was found to have
unacceptable rotor blades and the decision was made to remove and
replace this pump. (Reference KSC Shuttle Status 3/13/1997)

  On 3/11/97, Rollout of Space Shuttle Columbia from the Vehicle
Assembly Building to Pad 39A began at 6:32 a.m. The crawler
transporter was positioned under the mobile launcher platform (MLP)
with the Shuttle mounted on top and final preparations were made for
the 3.4 mile move to the pad.  Once at the pad, workers prepared to
hot fire auxiliary power unit No. 2. The Rotating Service Structure
was then placed around the vehicle Wednesday morning.  
(Reference KSC Shuttle Status 3/11/1997)

  On 3/10/97, Columbia's roll out to Pad 39A was delayed 24-hours due
to a liquid oxygen T-0 umbilical carrier plate alignment problem
encountered during operations to mate Columbia with the external tank
Friday/Saturday.  Also, the liquid hydrogen tail service mast required
minor repairs. Because of these issues, the Shuttle interface
verification test was delayed from Saturday to Sunday, 3/9/1997,
delaying roll out Tuesday. (Reference KSC Shuttle Status 3/10/1997)

  On 3/5/97, Columbia moved to the VAB shortly after noon. Inserts
necessary to secure an umbilical flow liner in the orbiter's 17-inch
disconnect area were installed overnight. Power-up was not required
and close-outs of the umbilical were complete. The orbiter was placed
on the orbiter transporter in the early morning on 3/5/97 and the
landing gear retracted.  Once in the Vehicle Assembly Building (VAB),
Columbia was lifted to the vertical position and hard mated to the
External Tank (ET) and Solid Rocket Boosters (SRB's) in VAB High Bay
No. 1. on 3/6/97. (Reference KSC Shuttle Status 3/05/1997) 

  On 2/27/97, preparations continue to roll Columbia to the VAB.
Final close-outs of the body-flap cove area are complete and the aft
engine compartment doors will be installed on Sunday, 3/2/97. 
Integrated hydraulic checks of the aerosurfaces and other orbiter 
systems will be completed tonight. On Monday, the orbiter will
be weighed and the center of gravity checks made. Early Tuesday, the
vehicle will be mated to the orbiter transporter. First motion is
expected to occur Tuesday afternoon. (Reference KSC Shuttle Status 2/27/1997)

  On 2/26/97, the strong backs have been removed from the payload bay doors
as preparations continue to roll Columbia to the VAB early next week. Final
repairs to minor corrosion in the body-flap cove area are complete and
close-outs are expected to be finished later today. Integrated hydraulic
checks of the aerosurfaces and other orbiter systems will begin tonight.
Aft engine compartment close-outs are also scheduled to be finished this
weekend. (Reference KSC Shuttle Status 2/26/1997)

  On 2/17/97, during scheduled modifications to existing lines in OPF
bay 2's hypergolic fuel system, monomethyl hydrazine (the liquid fuel
used in the orbiter's reaction control system) unexpectedly spilled
out onto two technicians doing the work. Other workers were also
treated for possible inhalation. All treated for either exposure or
possible inhalation were later released with no apparent serious
injuries. OPF bay 2, OPF bay 1 and the OPF Annex were evacuated at the
time of the spill. All but bay 2 was reopened about three hours after
the incident.  (Reference KSC Shuttle Status 2/18/1997)

  On 2/14/97, The spacelab transfer tunnel has been installed and an
interface verification test is scheduled for next week. Also, the
right hand Orbital Maneuvering System (OMS) pod has been installed and
cross-feed connections are complete. The crew of mission STS-83 arrived
for the Crew Equipment and Interface Test (CEIT) on 2/15/97. They spent
the time inspecting the orbiter and the spacelab which was installed 
into the payload bay on Feb. 1. (Reference KSC Shuttle Status 2/13/1997)

  On 1/30/97, the external tank was mated to the Solid Rocket Boosters
in the VAB.  (Reference KSC Shuttle Status 1/30/1997)

Orbit:
  Altitude:    184 statute miles
  Inclination: 28.45   
  Orbits:  
  Duration: 15 days,  16 hours, 29 minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: BI-086
  SRM:
  ET :  SN-84
  MLP : 
  SSME-1: SN-2012
  SSME-2: SN-2109
  SSME-3: SN-2019

Landing:  

   KSC 4/8/1997 2:33 pm EDT. Landing at KSC Shuttle Landing Facility (SLF) Runway 15. 
Main gear touchdown at 1:33:11 pm EDT (MET 3days 23hr 12min 39sec). Nose gear 
touchdown at 1:33:23 pm EDT (MET 3days 23hours 12min 51sec) and Wheel Stop at 
1:34:10 pm EDT (MET 3days 23hours 13min 38sec). 

   The first deorbit opportunity was on orbit 63 with an engine firing at 1:31 pm EDT.31 pm EDT.
  
   Landing was originally scheduled for KSC April 19 at 7:30am EDT.

Mission Highlights:

  STS-83 Flight Day 1 Highlights:

 On Friday, April 4, 1997, 5:00 p.m. CST, STS-83 MCC Status Report #1
reports: 
 
  The shuttle Columbia, carrying seven astronauts on board, blasted off
at 1:21 p.m. Central time from the Kennedy Space Center for the start
of a 16-day Spacelab microgravity research mission.

  Commander Jim Halsell, Pilot Susan Still, Mission Specialists Janice
Voss, Mike Gernhardt and Don Thomas and Payload Specialists Roger
Crouch and Greg Linteris blasted off into the mid-afternoon Florida
skies en route to an orbit about 170 statute miles above the
Earth. The crew will spend more than two weeks studying the behavior
of metals, materials and fluids in the absence of gravity and the
properties of combustion. The astronauts will be split into two teams
to conduct that work on a round-the-clock basis in the pressurized
Spacelab science module in Columbia's cargo bay.

  After the astronauts opened up Columbia's cargo bay, Voss and Crouch
began to activate Spacelab and experiment systems before entering the
Spacelab about 2 and a half hours into the mission. The Red team,
consisting of Halsell, Still, Thomas and Linteris, began a 7-hour
sleep period at 5 p.m. They'll be will be awakened at midnight to pick
up experiment work from Blue team members Voss, Crouch and Gernhardt,
who are scheduled to begin a full 8-hour sleep period at 1:21
a.m. Saturday.

 On Friday, April 4, 1997, 6:00 p.m. EST, STS-83 Payload Status Report #01
reports: (MET 0/04:39)

  This afternoon's picture-perfect launch of Space Shuttle Columbia
began a 16-day joint effort by the United States and 23 other
countries to explore a variety of scientific mysteries.

  Just before 6 p.m. CST this evening, Payload Commander Dr.  Janice
Voss and Payload Specialist Dr. Roger K. Crouch floated into the
Spacelab module aboard Columbia and began setting up their orbiting
research laboratory.

  "Everything's going great" said Mission Manager Teresa Vanhooser
from the Spacelab Mission Operations Control Center at the Marshall
Space Flight Center in Huntsville, Ala.  "We've planned and practiced
for this mission for a long time and it's wonderful to see it coming
together so well."

    Mission Scientist Dr. Mike Robinson of the Marshall Center said,
"We're tremendously excited about the opportunities that await us.  We
can't wait to get down to business -- the business of fundamental
scientific research in space."

  Over the next 12 hours, working with the science control team at
Marshall, Columbia's crew will begin their research by initiating
the protein crystal growth experiments, and firing up the onboard
furnace that uses electromagnetic force to suspend and mix various
samples of molten metals and alloys.  They will also start recording
how small disturbances aboard the Shuttle's laboratory affect the
experiments conducted onboard.

  This mission, Microgravity Science Laboratory 1, is primarily
dedicated to 33 experiments being conducted in the low-gravity
environment of space.  These investigations concentrate on unraveling
mysteries in three main areas: protein crystals, combustion and the
study of metals and alloys.  Also, this mission will test some of the
hardware, facilities and procedures that will be used on the
International Space Station.

  The unique benefit of research in microgravity is that important
scientific processes normally masked by gravity can be studied and
experiments which are impossible to conduct on the ground become
feasible.

  A major thrust of this mission's overall scientific effort is in
the area of protein crystal growth.  Grown in space, proteins ranging
from insulin to HIV-Reverse-Transcriptase have been produced as
larger, purer and new, never-before-seen crystal structures.  Only by
obtaining the highest possible quality of crystals can scientists
achieve the ultimate goal of this research -- determining the
three-dimensional structure or blueprint of the proteins.  By
unlocking the structural details, scientists can better understand how
they fit into the overall biology of the human body.

  Protein crystal growth is a recurring Space Shuttle experiment
because there are over 300,000 proteins in the human body and
scientists know the structure of less than 1 percent of them.

  The three Protein Crystal Growth Experiments on this mission will
attempt to grow a record number of nearly 1,500 protein crystal
samples.

  Knowledge from these studies will help to address the social costs
of illnesses and diseases -- now estimated at $900 billion annually
just in the United States.  These include cancer, diabetes,
alcoholism, Alzheimer's and AIDS.  Proteins associated with all of
these illnesses either have been studied in space or continue to be
part of ongoing experiments.

  Other experiments to be conducted aboard Columbia involve combustion
science -- the study of burning.  These are designed to help
researchers gain an understanding of the characteristics of fuels and
fires, which can lead to increased efficiency and reduced emissions in
internal combustion engines.

 In the United States, the yearly expenditure on crude oil is
estimated by the American Petroleum Institute as nearly $200 billion.
A mere 1 percent increase in fuel efficiency -- for instance,
improving a car's gas mileage from 25 mpg to 25.25 mpg - - would
translate into an overall savings for the United States of nearly 100
million barrels of oil a year, or roughly $5.5 million per day.

  In another category of experiments, scientists will study the mixing
of constituents in molten metals and alloys and the "undercooling" of
these mixed metals.  Undercooling followed by rapid freezing or
solidification is the process by which snowflakes are made.  A drop of
liquid can be cooled to a temperature below its normal freezing point,
yet still remain liquid.  The freezing process, when it occurs for
these undercooled liquids, is very rapid. When these metals solidify,
unique materials result that cannot be made or studied in any other
way.  Understanding the undercooling mixing process could lead to
better aircraft, car and truck engines, stronger construction
materials, as well as better foundry methods.  This research could
also lead to better welding, casting and soldering techniques.

  STS-83 Flight Day 2 Highlights:

 On Saturday, April 5, 1997, 6:30 a.m. CST, STS-83 MCC Status Report #2
reports: 

  The red team members of STS-83, Commander Jim Halsell and Pilot
Susan Still along with Mission Specialist Don Thomas and Payload
Specialist Greg Linteris have been busy continuing the payload
activation process begun by their blue team counterparts as the
research efforts of the first Microgravity Science Laboratory-1
(MSL-1) mission get into full swing.

  The STS-83 crew will spend more than two weeks studying the
properties of combustion and the behavior of metals, materials and
fluids in the absence of gravity.  The astronauts are split into red
and blue teams, each working a 12-hour shift, to allow
around-the-clock operations in the pressurized Spacelab science module
in Columbia's cargo bay.

  After being awakened just before midnight, Halsell and Still set up
the bicycle ergometer in the Shuttle's middeck area.  Each of the
STS-83 crewmembers will use the bicycle for exercise during the
flight.  Thomas activated the Large Isothermal Furnace (LIF)
experiment and the Expedite the Processing of Experiments to the
International Space Station (EXPRESS) rack while Linteris continued
the activation of Protein Crystal Growth experiments.

  Remaining activities in the red team's day will include the setup
and checkout of the Wireless Data Acquisition System (WDAS)
experiment.  This is a proof of concept payload that uses wireless RF
signals to relay data from temperature sensors in the payload bay and
spacelab module.  Analysis of future Space Station operation
requirements indicate that there may be a requirement for real time
monitoring of temperature readings in various parts of the station and
a system such as the WDAS could meet that need.

  Columbia's blue team of astronauts is scheduled to be awakened at
9:21 a.m. CST this morning to begin Flight Day 2 activities.  Columbia
continues to circle the Earth in a 187 x 184 s.m. orbit, completing
one full revolution of the Earth every 90 minutes.  Voss and Crouch
will conduct an interview with two television stations in the Rockford
Illinois area at 5:46 p.m. this afternoon.  Voss is a native of
Rockford.

 On Saturday, April 5, 1997, 6:00 a.m. EST, STS-83 Payload Status Report #02
reports: (MET 0/16:39)

  Overnight, the crew of the Microgravity Science Laboratory mission
continued to power on facilities in the Spacelab and began some of the
more than 30 experiments to be conducted during the 16-day mission.

  Yesterday evening, Mission Specialist Dr. Janice Voss activated the
High-Packed Digital Television to give scientists on Earth the ability
to view multiple channels of live video from the Spacelab.  This
technology allows scientists on the ground to monitor their
experiments, change parameters and improve the quality and quantity of
scientific information gathered during the mission.

  Payload Specialist Dr. Roger Crouch activated one protein crystal
growth experiment late yesterday. Voss later activated a second
experiment. The goal of these studies -- the Protein Crystallization
Apparatus for Microgravity and the Hand-Held Diffusion Test Cell -- is
to grow high-quality protein crystals which may be used to help
determine the three-dimensional structure and function of proteins in
the human body. Findings from this and other protein crystal growth
studies may lead to the development of new, more effective drugs to
fight diseases such as cancer, diabetes, alcoholism, AIDS and
Alzheimer's.

  All four acceleration measurement systems are now operating,
following activation of the Quasi-Steady and Space Acceleration
Measurement Systems by Voss last night. These systems work together to
detect and record the slight, unavoidable disturbances in the
near-zero gravity environment of the Spacelab. Science teams rely on
this information -- downlinked in near-real-time -- to determine the
effect of the disturbances on experiments.

  Before retiring for the day, Crouch configured the TEMPUS facility
for operations. This electromagnetic containerless processing furnace
will be used to study the undercooling and rapid solidification of
metals and alloys. Undercooling occurs when a solid is melted into a
liquid then cooled below its normal freezing point without
solidifying. "When the metal or alloy is solidified, it occurs very
rapidly, forming new types of materials we cannot manufacture or study
in any other way" said Jan Rogers, TEMPUS project scientist.

  A better understanding of this process may lead to improved welding,
casting and soldering techniques, and in turn, better products
manufactured using these processes.

  Voss and Crouch handed off to Mission Specialist Dr. Donald Thomas
and Payload Specialist Dr. Gregory Linteris around midnight. One of
the first orders of business for the oncoming crew was activating
another protein growth experiment -- the Vapor Diffusion
Apparatus. Flown on earlier missions, this device has helped
scientists define procedures and mixtures for efficient growth of
protein crystals in space. During this mission, researchers will
continue to study protein crystal mixtures to further enhance crystal
growth.

  Early this morning Thomas activated the Large Isothermal Furnace.
This facility will be used to study the diffusion of liquid metals --
the process by which liquid metals mix without stirring -- similar to
how a drop of food coloring disperses in a glass of water. This
process cannot be adequately studied on Earth because of fluid
movement caused by gravity.

  Thomas powered on the EXPRESS (Expedite the Processing of
Experiments to the Space Station) rack, an experiment support facility
designed to simplify and speed the process of housing, transporting,
installing and operating experiments planned for the International
Space Station.

  Following activation of the facility, Thomas initiated the Physics
of Hard Spheres Experiment to examine the changes which occur as
substances go from the liquid to the solid state and vice versa --
processes fundamental to materials processing. This research will
provide a better understanding of these transitional phases and may
result in improved techniques for processing materials on Earth.

  Ahead, Linteris will set up the Combustion Module to begin a study
of the properties of soot; and Thomas will begin a study in the Large
Isothermal Furnace to measure the fundamental variables which regulate
the diffusion of impurities in molten salts. Crouch and Voss will
assume science operations aboard the Shuttle around mid-day. Crouch
will power up the Middeck Glovebox facility for an experiment to study
the manipulation of fluid drops in low- gravity. Voss will configure
the Droplet Combustion Apparatus for a study of burning fuel droplets.

  STS-83 Flight Day 3 Highlights:

 On Sunday, April 6, 1997, 6:00 a.m. CST, STS-83 Payload Status Report #03
reports: (MET 1/16:39)

  After nearly two full days in space, the crew of the Microgravity
Science Laboratory mission has successfully activated all Spacelab
facilities and, along with science teams on the ground, is getting
down to the primary business of the mission -- to conduct fundamental
scientific research in space.

  Startup difficulties with one of the combustion experiments aboard
Space Shuttle Columbia were successfully resolved Saturday afternoon
and all research facilities are now fully operational.

  Working with Alternate Payload Specialist Dr. Paul Ronney at the
Spacelab Mission Operations Control Center in Huntsville, Ala.,
Payload Commander Dr.  Janice Voss changed a cable configuration. This
procedure resolved a communications glitch between a laptop computer
and the Combustion Module.  The module is a facility used to perform
experiments and to test combustion hardware and experiment methods on
Spacelab.

  Payload Specialist Dr. Gregory Linteris then activated the Laminar
Soot Processes experiment in the facility. This study, headed by
Dr. Gerard Faeth of the University of Michigan in Ann Arbor, is
collecting information on flame shape, the type and amount of soot
produced under various conditions and the temperature of soot
components. Carbon monoxide emissions associated with soot are the
primary source of fatalities in unwanted fires. Information gathered
from the study may lead to a better understanding of how to contain
unwanted fires and limit the number of fatalities from carbon monoxide
emissions.

  Twenty-three hours into the mission, just after noon Saturday, Voss
and Payload Specialist Dr. Roger Crouch of the mission's Blue Team
assumed science operations aboard the Shuttle.

  Late Saturday afternoon, Voss configured the Droplet Combustion
Apparatus for a study of burning fuel droplets. The study is gathering
information on burning rates of flames, flame structures and
conditions when a flame is extinguished.

  A major amount of the energy produced around the world comes from
burning fuels, said Dr. Vedha Nayagam, project scientist for the
Droplet Combustion Experiment, from NASA Lewis Research Center in
Cleveland, Ohio.  By studying burning fuel droplets in space and
comparing the results to theoretical models, we can learn about the
chemistry of these fuels. This will help us to burn these fuels more
efficiently and minimize pollutants.

  Crouch began his shift Saturday afternoon by powering up the Middeck
Glovebox facility to begin a fluid physics study which examines
non-contact and remote manipulation techniques for controlling the
position and motion of liquids in low-gravity. Results of this study
may find application in improving many important processes used by
chemical manufacturing industries on Earth, including the petroleum
technology, cosmetics and food sciences industries.

  Just prior to the end of the Blue Team's shift -- around 2:30
a.m. CDT Sunday -- Crouch completed the first of two runs of a study
being conducted in the Large Isothermal Furnace. This investigation is
a study of the diffusion of impurities in molten salts. Diffusion is
the process by which liquid metals mix without stirring -- similar to
how the smell of baking bread, for instance, spreads from the oven
throughout the house. This process cannot be adequately studied on
Earth because of fluid movement caused by gravity.

  The goal of the experiment is to determine the diffusion coefficient
of the sample -- a fundamental quantity which describes the diffusion
process. The study, headed by Dr. Tsutomu Yamamura of Tohoku
University in Sendai, Japan, is designed to reveal ideal conditions
for electrolysis of molten salts. Electrolysis is the use of an
electrical current to break down a dissolved substance into its
constituent components. Results may also benefit basic science and
engineering processes on Earth.

  Early this morning, when Red Team crew members began their 12-hour
shift, Mission Specialist Don Thomas initiated the first of two
studies in the Large Isothermal Furnace to test a specially designed
experiment cartridge. This cartridge will be used to conduct two of
the metallic alloy diffusion studies planned for later in the mission.

  Ahead, Thomas will continue the diffusion study in the furnace;
Linteris will continue the soot study in the Combustion Module; and
Thomas will continue the fluid drop study in the Glovebox. Prior to
handing over to the Blue Team, Thomas will transfer the plant growth
experiment in the Shuttle's Middeck to the EXPRESS rack. Voss and
Crouch will assume science operations aboard the Shuttle around
mid-day and continue fluid drop, droplet combustion and soot studies.

  While maintaining their primary focus on proceeding with normal
planned science operations, the experiment teams are also assessing
their options if Columbia's Fuel Cell #2 situation should impact
mission duration.

 On Sunday, April 6, 1997, 7:00 a.m. CST, STS-83 MCC Status Report #4
reports: 
 
 Science activities associated with the Microgravity Science
Laboratory-1 (MSL-1) payload are proceeding as planned while the
flight team in Houston continues to monitor the performance of one of
the shuttle's three fuel cell power units.

  The issue with fuel cell number 2 is a degradation in one portion of
the fuel cell.  There are three fuel cells on board Columbia, each
containing three stacks made up of two banks of 16 cells each.  In one
stack of fuel cell 2, the difference in output voltage between the two
banks of cells has been increasing.

  Late last evening, the shuttle's electrical power configuration was
adjusted to reduce the demands on fuel cell number 2.  Since the power
reconfiguration, the behavior of fuel cell number 2 has stabilized.
Flight controllers have decided to leave the shuttle's power systems
in their current condition while they monitor and evaluate trends.

  The Mission Management Team with hold a meeting at 8 a.m. CDT this
morning to assess the status of the fuel cell and the options
available for future flight operations. Shuttle managers will report
on the results of the meeting in a press briefing at 10 a.m. CDT.

 On Sunday, April 6, 1997, 12:00 p.m. CST, STS-83 MCC Status Report #5
reports: 
 
 Space shuttle managers today decided to cut short the STS-83
Microgravity Science Laboratory-1 mission because of problems with one
of the shuttle's three fuel cell power generation units.

   In a meeting that concluded at 9 a.m. CDT, NASA's Mission
Management Team (MMT) decided to order the early return due to data
received on fuel cell number 2, which has exhibited evidence of
internal voltage degradation since launch.  To ensure the safety of
the crew and Columbia, mission managers decided to reduce power demand
on the degraded cell and to isolate it from the other two fuel cells,
which are performing normally.  Meanwhile, flight controllers and
engineers on the ground are continuing analysis of fuel cell data in
order to decide whether to shut down the defective unit or to leave it
operating at minimum output in a standby mode.

  Columbia is now scheduled to land at 1:35 p.m. CDT Tuesday at
Kennedy Space Center. There is no concern for crew safety.

  The shuttle has three fuel cells, which use a reaction of liquid
hydrogen and liquid oxygen to generate electricity and produce
drinking water. Although one fuel cell produces enough electricity to
conduct on-orbit and landing operations, shuttle flight rules require
that all three be functioning well to ensure the safety of the crew
and provide sufficient backup capability for the highly dynamic
reentry and landing periods.

  Spacecraft Communicator Chris Hadfield informed the crew of the
decision at 9:21 a.m. CDT, saying: "The MMT had all players in on
the meeting right through from the factory.  The consensus is they
just do not understand the behavior of fuel cell 2. Even though your
efforts have done a good job toward stabilizing the problem, it's
significantly out of family. So, we'll shorten the mission"

  Commander Jim Halsell replied, "That's certainly a disappointment
but we know you guys put your best effort forward and you're doing the
right thing. We appreciate all the work that's gone into that"

  The early landing, which is only the third of the shuttle program
behind STS-2 in November 1981 and STS-44 in November 1991, means that
scientists will not be able to perform the majority of the research
planned for the MSL-1 mission. Columbia continues to circle the Earth
in a 188 x 183 statute mile orbit every 90 minutes with all of its
other systems operating normally.

 On Sunday, April 6, 1997, 6:00 p.m. CST, STS-83 Payload Status Report #04
reports: (MET 2/03:39)

  Microgravity Science Laboratory researchers at Marshall Space Flight
Center in Huntsville, Ala., are working to take maximum advantage of
the remaining hours before Space Shuttle Columbia's return to Earth
Tuesday. A malfunction in the Shuttle's number two fuel cell will end
the mission much earlier than the planned return on April 20.  Though
disappointed because of the need to cut the mission short, Mission
Manager Teresa Vanhooser at the Marshall Center said that the Spacelab
science control team was working with the crew members aboard Columbia
to reduce experiment run times and to realign the mission's schedule
to maximize the scientific return.  Researchers hope to get as many
science experiments completed as possible in the short time remaining.

  Despite this condensed time period, researchers have been able to
record a first in the Combustion Module.

  We've hit a homerun -- it's the first truly steady non-buoyant flame
that's been observed by anybody anywhere on Earth, said Combustion
Scientist Dr. Gerard Faeth from the University of Michigan, Ann
Arbor. While describing results from the Laminar Soot Processes
experiment, he stated that scientists have gotten their first glimpse
of the concentration and structure of soot from a fire burning in
microgravity. It's a real first and the pictures we saw today will
probably find their way into textbooks of the future, said Faeth.

  Much of the energy from fire is expelled in the soot it
produces. Researchers are gaining a better understanding of the role
soot plays in combustion and how it is produced by different
fuels. Soot has a lot of negative attributes and that's why we're
concerned about it. It's a pollutant, said Faeth. It is harmful to
public health.  It is the major source of difficulties of unwanted
fires in homes. Soot has carbon monoxide associated with it, which is
toxic and in that role soot is responsible for the deaths of about
4,000 people a year in the United States, and it's responsible for
fire injuries of about 25,000.

  Working in concert with science teams on the ground at the Marshall
Center, Columbia crew members Dr. Gregory Linteris and Dr. Don Thomas
continued experiments in TEMPUS, a German acronym for the
electromagnetic levitation furnace facility. These investigations were
pushed up in the timeline, according to William Hoffmeister, assistant
TEMPUS investigator at Marshall Center. The team was able to activate,
observe and complete an experiment run by melting a zirconium metal
sample and levitating it in the facility. This experiment, led by
Vanderbilt University Professor Robert Bayuzick, is studying the
relationship between internal flows in liquids and the amount of
undercooling that can be tolerated before solidification occurs. To
understand this experiment, Bayuzick said, imagine if you cooled a
glass of distilled water. The temperature could go below freezing
without the water actually becoming ice. That is undercooling.
However, if the glass were tapped or disturbed, then the water would
freeze very quickly. This process may have many benefits to
industry. New, enhanced properties in never-before-seen materials
could become possible.

  Thomas continued work in the middeck Glovebox as he conducted the
experiment called Internal Flows in a Free Drop. Tracer particles
inside the drop gave scientists the ability to map the internal flows
taking place as the drop was manipulated by sound waves. Understanding
the flows of fluids has far reaching applications for scientists in
the areas of weather prediction and ocean flows. Acoustic positioning
using this containerless technique is important to industries such as
chemical manufacturing, petroleum, cosmetics and food sciences.

  Later Thomas also set up the Large Isothermal Furnace for the Liquid
Phase Sintering experiment. This investigation tests theories on how
liquefied materials form a mixture without reaching the melting point
of the new alloy combination.

  Pilot Susan Still monitored the cooling samples from the earlier
Large Isothermal Furnace experiments. These dealt with the diffusion
of different types of metals.  Diffusion is a process where two
compounds mix -- much like how a droplet of food coloring will slowly
mix into a glass of water. After Columbia's return, researchers
will cut the column of lead-tin-telluride into segments to study how
uniform the various components mixed during sample cooling.

  Before the end of his shift, Linteris continued work in the
combustion module, performing the Droplet Combustion Experiment. The
purpose of this experiment is to collect information on the burning
rates of flames, flame structures and conditions when extinguishing a
flame. With improved understanding of droplet combustion, the results
of this experiment could lead to cleaner and safer ways to burn fossil
fuels, and more efficient methods of generating heat and power on
Earth.

  The experiment, Coarsening in Solid-Liquid Mixtures investigation
was moved up in the schedule as well. This experiment may help
researchers develop improved manufacturing processes and stronger
alloys. Because the coarsening experiment was moved up, it was decided
that the Astro/Plant Generic Bioprocessing Apparatus would remain
stowed in the middeck compartment.

  Meanwhile, protein crystal growth experiments continue unattended as
planned.

  During this shift, researchers also dealt with a temporary
malfunction of the Experiment Control Systems Computer. This computer
oversees all the experiments aboard Spacelab. Commander Jim Halsell
Jr. ran trouble shooting steps to remedy the problem. Science
experiments continued after only a short interruption.

 On Sunday, April 6, 1997, 6:00 p.m. CST, STS-83 MCC Status Report #07
reports: ()

  This afternoon, Columbia's crew shut down one of three
electricity-generating fuel cells that had been experiencing problems
since shortly after launch and made plans for ending the STS-83
mission on Tuesday, 12 days early, following a decision by shuttle
managers this morning to shorten the flight.

  Science activities are continuing inside the Microgravity Science
Lab-1 today, however, with the two remaining fuel cells operating
normally and supplying electricity for the lab experiments and for
Columbia's systems. The laboratory module is not planned to be
deactivated until late Monday evening as the crew readies for the
Tuesday return to Earth. Fuel cell 2, as the problem cell is
designated, was shut down by the crew at about 2:30 p.m. CDT
today. After the fuel cell was shut down, the crew also powered down
several pieces of non-critical equipment aboard Columbia to provide
additional power for the experiment work.

  Columbia's Commander Jim Halsell, Pilot Susan Still and Mission
Specialist Don Thomas will answer questions from media at JSC, the
Kennedy Space Center, Fl., and the Marshall Space Flight Center,
Huntsville, Al., in a 20-minute press conference planned for 8:31
a.m. CDT Monday.

  The three shuttle fuel cells generate electricity by combining
liquid hydrogen and oxygen and creating, as a byproduct,
water. Although only one operational fuel cell can provide sufficient
electricity to safely conduct Columbia's orbital and landing
operations, shuttle managers decided to end the mission early due to
the loss of the failed fuel cell as a backup to the two currently
operating cells.  The loss of the fuel cell also reduces the amount of
power available for experiments.

  Later this afternoon, flight controllers noted an apparent problem
with one of two Pulse Code Master Modulation Units (PCMMUs) on
Columbia as the crew was working with a computer that controls
experiments in the Spacelab module. The two PCMMUs serve as relay
stations to transmit data and telemetry from a variety of sources on
board to the ground and to the Columbia's five flight control
computers. The crew switched to the second PCMMU and have not
experienced further problems, and flight controllers are continuing to
analyze the trouble. The problem did not interrupt the ongoing science
operations. Columbia is now scheduled to land at 1:35 p.m. CDT Tuesday
at Kennedy Space Center.

  STS-83 Flight Day 4 Highlights:

 On Monday, April 7, 1997, 7:00 a.m. CST, STS-83 Payload Status Report #05
reports: (MET 02/16:39)

  Spacelab crew members and science teams at Marshall Space Flight
Center in Huntsville, Ala., worked steadily through the night to
complete as much science as possible in the remaining hours of the
mission. Due to a malfunction in the Space Shuttle's number two fuel
cell, Columbia is now scheduled for landing Tuesday afternoon.

  The abbreviated mission came as a disappointment to participating
scientists.  The atmosphere, however, was also marked by bright spots,
such as the excitement of one science team which recorded a
"first" in combustion research.  Payload Commander Dr. Janice
Voss completed several runs of the Droplet Combustion Experiment last
night. "Six burns were successful and for the first time, we're
burning free droplets" said Principal Investigator Dr. Forman
Williams of the University of California at San Diego.

  The experiment is collecting information on burning rates of flames,
flame structures and conditions under which flames are
extinguished. "We can't get this kind of information from
ground-based experiments" said Williams. "We have burned at two
different atmospheres of oxygen concentration and calculated the
burning times of free fuel droplets at each."

  Combustion of fuel droplets is an important element in heating
furnaces for materials processing, heating homes and businesses, and
producing energy in gas turbines and gasoline-powered
engines. Findings from this investigation are providing researchers
with a better understanding of the combustion process and may lead to
cleaner and safer ways to burn fossil fuels as well as more efficient
methods of generating heat and power on Earth.

  The Coarsening in Solid-Liquid Mixtures experiment continued to run
in the Middeck Glovebox facility. This investigation, led by Dr. Peter
Voorhees of Northwestern University in Evanston, Ill., is studying
coarsening in metal mixtures at very high temperatures. During
coarsening, small particles shrink by losing atoms to larger
particles, resulting in a lack of uniform particle distribution. This
weakens the material and shortens its life-span.

  "Because of our small size and power usage we've been able to
continue experiment runs, completing four runs with good success"
said John Caruso, project manager for the experiment, with NASA's
Lewis Research Center. "From the engineering data we've
received, we expect to get satisfactory science. We expect the samples
will show uniform particle distribution."

  Findings from this research may lead to improved manufacturing
processes and stronger, longer-lasting materials.

  Early Sunday evening, Payload Specialist Dr. Roger Crouch began a
study of the Structure of Flame Balls at Low Lewis-number, called
SOFBALL, in the Combustion Module. The study is designed to determine
under what conditions a stable flame ball can exist and if heat loss
is responsible in some way for the stabilization of the flame ball
during burning.

  "The two completed runs were successful beyond my wildest dreams"
said Principal Investigator Dr. Paul Ronney of the University of
Southern California in Los Angeles. During the first experiment, a
mixture of hydrogen, oxygen and carbon-dioxide burned in the facility
for the entire 500-second limit. This result is significant because
"these are the weakest flames ever burned -- lowest temperature,
weakest, most diluted mixtures" explained Ronney. "These mixtures will
not burn in Earth's gravity."

  "We have known that burning weaker mixtures increases efficiency"
said Ronney, "but not much is known about the burning limits of
these mixtures." Findings from this experiment will also provide
researchers with a better understanding of the combustion process and
will help to improve theoretical models. "Combustion models give
different results for these types of flames" said Ronney.  "This
is an acid test to show which, if any, current combustion modules
should be used."

  The Experiment Control Systems Computer, which relays
ground-commands to the experiment facilities, malfunctioned. The
Spacelab crew performed a procedure to disconnect the computer from
the master timing unit, allowing the computer and experiments to go to
internal timing sources.

  In the electromagnetic containerless processing facility, called
TEMPUS, two experiment runs ended early when the undercooled,
levitated samples came in contact with the wall. Undercooling refers
to a liquid being cooled to a temperature below its normal freezing
point yet remaining in a liquid state -- like cooling a glass of
distilled water on Earth. However, if the glass is tapped or
disturbed, ice begins to form quickly -- just as the samples began to
solidify when they hit the wall. Another study of undercooled
materials was initiated in the facility. This experiment, which
measures the specific heat of undercooled metallic melts, is examining
how metallic glass forms in zirconium-based alloys.

  Before ending his shift early this morning, Crouch began another run
of the Liquid Phase Sintering experiment in the Large Isothermal
Furnace. This experiment is investigating how liquid metals form a
mixture without reaching the melting point of the formed metallic
alloy. Information gathered will provide researchers with a better
understanding of liquid phase sintering in low-gravity and comparisons
of findings to theoretical predictions, should improve theoretical
models. The principal investigator for the study is Dr. Randall German
of Pennsylvania State University in University Park, Pa.

  Dr. Donald Thomas and Dr. Gregory Linteris assumed science
operations aboard the Shuttle early this morning. Thomas completed
another run of the Liquid Phase Sintering experiment in the Large
Isothermal Furnace before beginning to deactivate protein crystal
growth experiments.

  After completion of another run of the Droplet Combustion
Experiment, Linteris began reconfiguring the Droplet Combustion
Apparatus for return to Earth.

  Ahead, crew members will continue to deactivate experiment
facilities in preparation for the Shuttle's journey home.

 On Monday, April 7, 1997, 7:30 a.m. CST, STS-83 MCC Status Report #7
reports: 

  Microgravity research aboard the Shuttle Columbia neared an end this
morning as the astronauts prepared to check out the Shuttle's
flight control systems that will be used during tomorrow's landing
at the Kennedy Space Center

  Commander Jim Halsell and Pilot Susan Still will check out
Columbia's aerosurfaces which are used to control the Shuttle after
it reenters the Earth's atmosphere and will test fire the ship's
maneuvering jets used to steer the Shuttle while it is in space.  The
tests will be completed before Red team crew members Halsell, Still,
Mission Specialist Don Thomas and Payload Specialist Greg Linteris go
to bed for what is expected to be their final sleep period on orbit.

  Blue team crew members Janice Voss, Mike Gernhardt and Roger Crouch
will finish up science activities this afternoon and will deactivate
Spacelab systems in the pressurized research module shortly after 9
p.m. tonight.

  With Columbia's mission having been cut short because of a
voltage problem with fuel cell number 2, which was shut down and safed
yesterday, the astronauts will spend part of the day stowing their
crew cabin for their return to Earth tomorrow. All of Columbia's
other systems are functioning in excellent condition, including the
two remaining fuel cells which are carrying the load of electrical
production for the orbiter and the Spacelab.

  Columbia and its crew are scheduled to return home tomorrow
afternoon.  The deorbit burn to drop Columbia out of orbit is
scheduled for 12:35 p.m. Central time.  Landing at Kennedy Space
Center's Shuttle landing facility would take place one hour later
at 1:35 p.m. with additional opportunities available on subsequent
orbits to their KSC or the backup landing site at Edwards Air Force
Base, California.

 On Monday, April 7, 1997, 5:00 p.m. CST, STS-83 MCC Status Report #8
reports:
 
  Columbia's seven astronauts spent what should be their last full day
on orbit preparing to close down science operations and ready their
vehicle for a Tuesday landing at the Kennedy Space Center.

  This morning, mission commander Jim Halsell and pilot Susan Still
conducted a routine pre-entry check of Columbia's flight control
systems and performed a hot fire test of the reaction control system
jets.  One jet, designated F3F, failed off during the test, but does
not affect reentry plans since redundant jets perform the same
function as the failed jet.

  Halsell and Still, together with their Red Team partners Don Thomas
and Greg Linteris, participated in a crew news conference talking with
media in Houston, Florida and Alabama.  The crew remarked that while
the short mission was a disappointment to them, they feel significant
science had been accomplished in the few days of Spacelab operations.

  On the ground, flight controllers continue to manage electrical
power loads on the spacecraft.  They also performed troubleshooting
procedures on an experiment control computer for the Spacelab module
and on the minus-Y startracker, part of the Shuttle's navigation
system.  One of two startrackers, the minus-Y unit showed indications
that it was not communicating properly with other components and,
after troubleshooting procedures were run, was considered failed.
There is no impact to the mission since the remaining minus-Z
startracker continues to perform well and the startrackers are
designed to work independently of one another to provide information
to Columbia's Inertial Measurement Units.

  Columbia and its crew are scheduled to return to the Kennedy Space
Center on Tuesday afternoon.  The deorbit burn to drop Columbia out of
orbit is scheduled for 12:31 p.m. Central time.  Landing at Kennedy
Space Center's Shuttle landing facility would take place one hour
later at 1:33 p.m. with additional opportunities available on
subsequent orbits to either KSC or the backup landing site at Edwards
Air Force Base, California.  Weather appears acceptable at both sites,
although crosswinds will be near normal limits.

  STS-83 Flight Day 5 Highlights:

 On Tuesday, April 8, 1997, 7:30 a.m. CST, STS-83 MCC Status Report #9
reports:

Science work aboard Columbia has been completed and the Spacelab 
module has been deactivated as the seven astronauts prepare for their 
return to Earth later today.

Overnight, Blue team crewmembers, Janice Voss, Mike Gernhardt  
and Roger Crouch shut down equipment and experiments being carried 
in the pressurized Spacelab module and the laboratory was deactivated 
just before midnight.  The Red team astronauts, Commander Jim Halsell, 
Pilot Susan Still, Mission Specialist Don Thomas and Payload Specialist 
Greg Linteris were awakened at 1:21 a.m. Central time.  After a quick 
handover with their blue team counterparts, the red team began stowing 
equipment that was used during the flight in preparation for the Shuttles 
return to Earth.  Voss, Gernhardt and Crouch began an abbreviated 6 hour 
sleep period. Once they were awakened, the astronauts began deorbit 
preparations for their anticipated landing later today at the Kennedy
Space Center.

Columbias deorbit burn is planned for 12:31 p.m. Central time for a KSC 
landing at the 3 mile long landing strip at the Florida spaceport one 
hour later at 1:33 p.m., although the backup landing site at California's
Edwards Air Force Base could be used on the same orbit if the weather 
in Florida does not cooperate. Currently, conditions at KSC are expected 
to be favorable for landing.  Backup landing opportunities exists on 
both coasts on subseqent orbits, if needed. A 3  minute firing of the 
twin orbital maneuvering system engines will reduce Columbias velocity 
enough to allow the Shuttle to drop out of orbit and begin the journey
home.  About 30 minutes after the deorbit burn, Columbia will begin to
encounter the first traces of Earths atmosphere at an altitude of 4
00,000 feet as it travels west of Hawaii.

No significant changes are planned in the management of Shuttle systems
for entry and landing.  Due to the loss of fuel cell two, flight 
controllers plan to have some of the Shuttles navigation equipment po
wered off for the early portion of entry as the flight rules call for.  
Those systems will be activated about 20 minutes before landing.

The STS-83 astronauts will spend the night at the landing site and will 
return to the Johnson Space Center at about midday Wednesday.

<end of mission>

Mission Name: STS-84 (84)
  Atlantis (19)         
  Pad 39- () (estimated)
  84th Shuttle Mission (estimated)
  19th Flight OV-104 (estimated)
   6th Mir docking (estimated)

Crew:
  Charles J. Precourt (3), Mission Commander
  Eileen M. Collins (2), Pilot
  C. Michael Foale (4), Mission Specialist
  Carlos I. Noriega (1),  Mission Specialist
  Edward T. Lu, (1),  Mission Specialist 
  Jean-Francois Clervoy (2), (ESA) Mission Specialist
  Elena V. Kondakova (2), (RSA) Mission Specialist

 Download from Mir
  Jerry M. Linenger 

  NOTE: C. Michael Foale will will stay aboard Mir,  replacing 
  Jerry M. Linenger who will have arrived on Mir from STS-81.

Milestones:
   OPF-3 -- 1/22/97 (Reference KSC Shuttle Status 1/22/1997)
     VAB -- 4/10/97 Estimated (Reference KSC Shuttle Status 3/28/1997)
     PAD -- 

Payload:
  Mir-Docking/6, SpaceHab-DM

  (Reference KSC Shuttle Status Mar 1997)
  (Reference KSC Shuttle Status Apr 1997)

Mission Objectives:
  The 6th Mir Docking mission will carry a Spacehab double module and
will have Atlantis docked with the station for five days transferring
in addition to an astronaut exchange.  The shuttle previously Mir
missions were STS-71, STS-74, STS-76, STS-79 and STS-81.

Launch:  

  Launch May 15, 4:07am 1997 (ESTIMATED).  Launch window is 7-10 minutes.

 On 3/28/97, New thruster seals were installed in Atlantis' aft 
Reaction Control System (RCS). The forward Reaction Control System is
scheduled to be returned to the OPF this weekend and reinstalled on
the orbiter later. Close-outs of the orbiter's midbody continued
and Main Propulsion System (MPS) vacuum line leak checks were performed.
(Reference KSC Shuttle Status 3/28/1997)

 On 3/25/97, The forward reaction control system was removed from
Atlantis to allow for additional checks of the thruster seal
savers. X-rays of the FRCS will continue today. Securing of main
engine No. 3 also continues. In the VAB, the external tank was mated
to the solid rocket boosters 3/24/97.  (Reference KSC Shuttle Status 3/25/1997)

 On 3/5/97, The forward reaction control system was mechanically
installed on the orbiter overnight. Electrical connections continued
and the Space Shuttle Main Engines (SSME's) will be installed
beginning 3/6/97. Engine No. 1 has already been delivered to the OPF
in preparation for this work. Orbital Maneuvering System (OMS) pod
close-outs and mid-body close-outs continue in work.
(Reference KSC Shuttle Status 3/05/1997)

 On 2/27/97, The European Proximity Sensor (EPS) payload has been
installed and the interface verification test is now in work. A
functional check of the airlock hatches is also underway. Preparations
continue for Space Shuttle main engine installation and forward
reaction control system installation next week. Stacking of the solid
rocket boosters in the Vehicle Assembly Building is complete and joint
close-outs are underway. (Reference KSC Shuttle Status 2/27/1997)

 On 2/26/97,  Decay checks on the Power Reactant and Storage Distribution System     
(PRSDS) and close-outs of the Orbital Maneuvering System (OMS) continue. The
European Proximity Sensor (EPS) payload has been installed and the
Interface Verification Test (IVT) is scheduled to take place tomorrow.
Stacking of the solid rocket boosters in the Vehicle Assembly Building
also continues. Mate of the external tank to the solid rocket boosters
is now scheduled for March 24. (Reference KSC Shuttle Status 2/26/1997)

 On 2/18/97, Securing of APU No. 3 and work to hook-up the fuel line
was completed. A leak and functional test of the newly installed APU
was then performed. Also, the main landing gear's right inboard brakes
were removed and replaced. The Orbital Maneuvering System (OMS) pod
functional checks were performed on 2/18/97 and 2/19/97.  Stacking of
the Solid Rocket Boosters (SRB's) in the VAB resumed following repairs 
to the fine control mechanism (hydraset) on the crane. 
(Reference KSC Shuttle Status 2/18/1997)

 On 2/14/97, removal of the left hand pod will not be required
(removal was considered due to concerns with the engine actuator
controller) and work is underway to complete the Orbital Maneuvering System 
(OMS) functional checks.  Stacking of the Solid Rocket Boosters (SRB's) has
been delayed several days due to problems with a fine control
mechanism (hydraset) for the crane. Work is being rescheduled to least
impact external tank/solid rocket booster mating operations. Workers
hope to resume booster stacking operations on Monday (2/17/97).
(Reference KSC Shuttle Status 2/14/1997)

  On 2/13/97, functional checks of the orbital maneuvering system were
performed. Removal of the FRCS was completed last weekend. Auxiliary
power Unit (APU) No. 3 has been replaced and securing of the new APU
is in work today. Stacking of the solid rocket boosters for mission
STS-84 was underway in the VAB. (Reference KSC Shuttle Status 2/13/1997)

Orbit:
  Altitude: 184 statute miles    
  Inclination: 51.6
  Orbits:  
  Duration: 9 days, 3 hours, 45 minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: BI-087
  SRM:
  ET :  SN-85
  MLP : 
  SSME-1: SN-2032
  SSME-2: SN-2039
  SSME-3: SN-2029

Landing:  
  KSC May 24 8:12 am (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-85 (85)
  Discovery (23)         
  Pad 39- () (estimated)
  85th Shuttle Mission (estimated)
  23rd Flight OV-103 (estimated)

Crew:
  Curtis L. Brown, Jr (4), Mission Commander
  Kent V. Rominger (3), Pilot
  N. Jan Davis (3), Mission Specialist
  Robert L. Curbeam, Jr. (1), Mission Specialist
  Stephen K. Robinson (1), Mission Specialist
  Bjarni Tryggvason (1),(CSA) Payload Specialist

  Note:   Jeffrey S. Ashby (1), Pilot was previously assigned
          as pilot of STS-85.

Milestones:
   OPF-2 -- 
     VAB -- 
     PAD -- 

Payload:
  CRISTA, IEH-2, MIM, TAS-01, MFD, MAHRSI, SEH, UVSTAR

  (Reference KSC Shuttle Status Mar 1997)

Mission Objectives:

    During the flight, Davis will use Discovery's robot arm to                 
deploy the CRISTA-SPAS payload (Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere - 
Shuttle Pallet Satellite) for about 9 days of free-flight. CRISTA-SPAS 
consists of three telescopes and four spectrometers that
will measure trace gases and dynamics of the Earth's middle
atmosphere. Davis also will operate the robot arm for CRISTA-SPAS 
retrieval.
 
     Two other instruments mounted on the Shuttle Pallet Satellite
also will study the Earth's atmosphere. The Middle Atmosphere High
Resolution Spectrograph Instrument (MAHRSI) will measure hydroxyl and
nitric oxide by sensing UV radiation emitted and scattered by the
atmosphere, while the Surface atomic oxygen on optical materials.
                                                                           
     The Shuttle Pallet Satellite on which the scientific instruments
are mounted is a self-contained platform that provides power, command,
control and communication with Discovery during free-flight. CRISTA-SPAS 
previously flew on STS-66 in 1994. STS-85 will mark the fourth in a 
series of missions designed to study the Earth's atmosphere.
 
    The crew also will support the Manipulator Flight Development
(MFD) investigation being sponsored by NASDA, the Japanese Space
Agency.  MFD consists of three separate experiments located on a
support truss in the payload bay and is designed to demonstrate
applications of the Shuttle's robot arm for possible use on the
Japanese Experiment Module of the International Space Station.
 
     Several Hitchhiker payloads, including the 
Technology Applications and Science Payload (TAS-01), the 
International Extreme Ultraviolet Hitchhiker (SEH), and the 
Ultraviolet Spectrograph Telescope for Astronomical Research (UVSTAR) 
will be housed in Discovery's payload bay, operating independently 
of crew support during the flight.  

     The Microgravity Vibration Isolation Mount (MIM) experiment
will be operated by Canadian Space Agency astronaut Bjarni Tryggvason.
The MIM experiment is a small double-locker size device designed to
isolate International Space Station payloads and experiments from
disturbances created by thruster firings or crew activity.  MIM will
be operated for 30 hours with real-time data transmission
to investigators on the ground.  (Reference NASA Press Release 96-224)

Launch:  
  Launch July 17, 1997 10:06am (ESTIMATED). Launch window is 1 hour, 54 minutes.
  On 3/25/97, Space Shuttle Main Engines (SSME) No. 1 and 3 have been removed
and Engine No. 2 will be removed. The forward Reaction Control System (RCS) 
functional checks continue today. Work to remove and replace fuel cell 
No. 2 will begin 3/27/97. (Reference KSC Shuttle Status 3/25/1997)

  On 3/5/97, deservicing of Discovery's hypergolic system began. This
hazardous operation to remove residuals from the Reaction Control
System (RCS) keeps the bay closed to non-essential personnel and other
work through most of the day.  An orbiter navigational aid activation
test is scheduled for 3/6/97 and hydraulic system inspections will
begin.  (Reference KSC Shuttle Status 3/05/1997)

Orbit:
  Altitude: 160nm   
  Inclination: 57
  Orbits:  
  Duration: 11 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: BI-088
  SRM:
  ET :  SN-86
  MLP : 
  SSME-1: SN-2041
  SSME-2: SN-2040
  SSME-3: SN-2042

Landing:  
  KSC July 28 at about 6:54 am (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-86 (86)
  Atlantis (20)         
  Pad 39-A () (estimated)
  86th Shuttle Mission (estimated)
  20th Flight OV-104 (estimated)

Crew:
  James D. Wetherbee (4), Commander
  Michael J. Bloomfield (1), Pilot
  Vladimar G. Titov (5), (RSA) Mission Specialist
  Scott E. Parazynski (2), Mission Specialist
  Jean-Loup J.M. Chretien, (CNES) Mission Specialist 
  Wendy B. Lawrence (2), Mission Specialist

 Download:
  C. Michael Foale

 NOTE: Wendy B. Lawrence will replace C. Michael Foale onboard MIR and will 
       join the Mir 24 crew. She will be replaced by David A. Wolf on STS-89.

  (Reference the Crew's Personal World Wide Web page)

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

  (Reference KSC Shuttle Status Mar 1997)

Payload:
  Mir-Docking/7, SpaceHab-DM

Mission Objectives:
  The 7th Mir Docking mission will carry a Spacehab double module and
will have Atlantis docked with the station for five days transferring
in addition to an astronaut exchange. The shuttle previously Mir
missions were STS-71, STS-74, STS-76, STS-79, STS-81 and STS-84.
  
  Highlights of the 9-day mission include five days of docked
operations between Atlantis and Mir and the exchange of crew members
Foale and Lawrence to continue a permanent American presence of the
Russia complex.  A spacewalk is scheduled to retrieve the four Mir
Environmental Effects Payloads which were attached to the Mir's
docking module by Linda Godwin and Rich Clifford during STS-76 to
characterize the environment surrounding the Mir space
station. Atlantis will carry the SPACEHAB double module to support the
transfer of logistics and supplies for Mir and the return of
experiment hardware and specimens to Earth.

Launch:  
  Launch September 18, 1997 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.6
  Orbits:  
  Duration: 9 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET : SN-87 
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-87 (87)
  Columbia (23)         
  Pad 39- () (estimated)
  87th Shuttle Mission (estimated)
  23rd Flight OV-102 (estimated)

Crew:
  Kevin R. Kregel (3), Commander
  Steven W. Lindsey (1), Pilot
  Winston E. Scott (2), Mission Specialist
  Kalpana Chawla (1), (NASDA) Mission Specialist
  Takao Doi (1), (NASDA) Mission Specialist
 
Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
  USMP-4, SPARTAN-201-04

Mission Objectives:
  Spartan 201-04 is a Solar Physics Spacecraft designed to perform
remote sensing of the hot outer layers of the sun's atmosphere or
corona. The objective of the observations are to investigate the
mechanisms causing the heating of the solar corona and the
acceleration of the solar wind which originates in the corona. The
fourth Spartan 201 mission, SP201-04, is coordinated with the ongoing
ESA/NASA SOHO mission. The previous two flights of SP201 were
coordinated with the passage of the Ulysses spacecraft over the sun's
south and north poles. Ulysses is an ESA deep space solar physics
spacecraft launched in 1990 which performs in-situ measurements of the
solar wind

Launch:  
  Launch October 9, 1997 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.6
  Orbits:  
  Duration: 9 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  SN-88
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-88 (88)
  Endeavour ()         
  Pad 39- () (estimated)
  88th Shuttle Mission (estimated)
  xxth Flight OV-105 (estimated)
  1st USA Space Station Assembly Flight

Crew:
  Robert D. Cabana (4), Mission Commander
  Frederick W. Sturckow (1), Pilot
  Nancy J. Currie (3), Mission Specialist
  Jerry L. Ross (6), Mission Specialist
  James H. Newman (3), Ph.D, Mission Specialist

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
  Space Station Assembly Flight, Node 1, PMA1/2

Mission Objectives:
     The seven-day mission will be highlighted by the mating of
the U.S.-built Node 1 station element to the Functional Energy
Block (FGB) which will already be in orbit, and two spacewalks
to connect power and data transmission cables between the Node
and the FGB.  The FGB, built by Boeing and the Russian Space
Agency, is scheduled for launch on a Russian Proton rocket from
the Baikonur Cosmodrome in Kazakstan in November 1997.

     Node 1 will be the first Space Station hardware delivered
by the Space Shuttle.  It has two Pressurized Mating Adapters
(PMA), one attached to either end.  One PMA is permanently
mated to the FGB and the other used for orbiter dockings and
crew access to the station.  Node 1 also will contain an
International Standard Payload Rack used to support on-orbit
activities once activated after the fifth Shuttle/Station
assembly flight.

     To begin the assembly sequence, the crew will conduct a
series of rendezvous maneuvers similar to those conducted on
other Shuttle missions to reach the orbiting FGB.  On the way,
Currie will use the Shuttle's robot arm to place Node 1 atop
the Orbiter Docking System.  Cabana will complete the
rendezvous by flying Endeavour to within 35 feet of the FGB,
allowing Currie to capture the FGB with the robot arm and place
it on the Node's Pressurized Mating Adapter.
 
     Once the two elements are docked, Ross and Newman will
conduct two scheduled spacewalks to connect power and data
cables between the Node, PMAs and the FGB.  The day following
the spacewalks, Endeavour will undock from the two components,
completing the first Space Station assembly mission.

Launch:  
  Launch December 4, 1997 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.6
  Orbits:  
  Duration: 7 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-89 (89)
  Discovery (24)         
  Pad 39- () (estimated)
  89th Shuttle Mission (estimated)
  xxth Flight OV-103 (estimated)

Crew:

  Download:
    Wendy B. Lawrence (Mir 24-25 / STS-86) will return on STS-89

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
  Mir-Docking/8, SpaceHab-DM

Mission Objectives:

Launch:  
  Launch January 15, 1998 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.6
  Orbits:  
  Duration: 9 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-90 (90)
  Columbia (24)         
  Pad 39- () (estimated)
  90th Shuttle Mission (estimated)
  24th Flight OV-102 (estimated)

Crew:
  TBD, commander
  TBD, pilot
  Richard M. Linnehan DVM (2), Mission Specialist 
  Dafydd Rhys Williams MD (1),   Mission Specialist 

  Selection Trainees (only 2 will fly, and 2 will be alternates)
  Dr. Jay C. Buckey (0), Payload Specialist
  Dr. Alexander W. Dunlap (0), Payload Specialist
  Dr. Chiaki Mukai (1) (NASDA), Payload Specialist
  Dr. James A. Pawelczyk (0), Payload Specialist    

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
  Neurolab

Mission Objectives:

Launch:  
  Launch March 5, 1998 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 28.45
  Orbits:  
  Duration: 16 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-91 (91)
  Discovery (25)         
  Pad 39- () (estimated)
  91th Shuttle Mission (estimated)
  xxth Flight OV-103 (estimated)

Crew:

 Download:
   David Wolf (Mir-25/STS-89) will return

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
  Mir-Docking/9, AMS, SpaceHab-SM

Mission Objectives:

Launch:  
  Launch May 21, 1998 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.60
  Orbits:  
  Duration: 9 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-92 (92)
  Endeavour ()         
  Pad 39- () (estimated)
  92nd Shuttle Mission (estimated)
  xxth Flight OV-105 (estimated)

Crew:

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
  Space Station Assembly Flight SSAF-2 (Z1 Truss)

Mission Objectives:

Launch:  
  Launch July 2, 1998 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.60
  Orbits:  
  Duration: 9 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-93 (93)
  Columbia (25)         
  Pad 39- () (estimated)
  93rd Shuttle Mission (estimated)
  25th Flight OV-102 (estimated)

Crew:

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
  AXAF-1

Mission Objectives:

Launch:  
  Launch August 27, 1998 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 28.4
  Orbits:  
  Duration: 5 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-94 (94)
  Discovery (26)         
  Pad 39- () (estimated)
  94th Shuttle Mission (estimated)
  xxth Flight OV-103 (estimated)

Crew:

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
 Space Station Assembly Flight SSAF-3 (P6, PV Module)

Mission Objectives:

Launch:  
  Launch October 22, 1998 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.6
  Orbits:  
  Duration: 8 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-95 (95)
  Endeavour ()         
  Pad 39- () (estimated)
  95th Shuttle Mission (estimated)
  xxth Flight OV-105 (estimated)

Crew:

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
 Space Station Assembly Flight SSAF-4 (US Lab)

Mission Objectives:

Launch:  
  Launch November 19, 1998 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.6
  Orbits:  
  Duration: 9 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-96 (96)
  Atlantis (21)         
  Pad 39- () (estimated)
  96th Shuttle Mission (estimated)
  21st Flight OV-104 (estimated)

Crew:

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
 Space Station Assembly Flight SSAF-5 (MPLM,SLP)

Mission Objectives:

Launch:  
  Launch January 14, 1999 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.6
  Orbits:  
  Duration: 11 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-97 (97)
  Discovery (27)         
  Pad 39- () (estimated)
  97th Shuttle Mission (estimated)
  xxth Flight OV-103 (estimated)

Crew:

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
 Space Station Flight SSUF-1 (MPLM,SLP)

Mission Objectives:

Launch:  
  Launch March 11, 1999 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.6
  Orbits:  
  Duration: 8 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-98 (98)
  Endeavour ()         
  Pad 39- () (estimated)
  98th Shuttle Mission (estimated)
  xxth Flight OV-105 (estimated)

Crew:

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
  Space Station Assembly Flight SSAF-6 (Airlock, SLP)

Mission Objectives:

Launch:  
  Launch April 8, 1999 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.6
  Orbits:  
  Duration: 9 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-99 (99)
  Atlantis (22)         
  Pad 39- () (estimated)
  99th Shuttle Mission (estimated)
  22nd Flight OV-104 (estimated)

Crew:

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
  Space Station Assembly Flight SSAF-7 (S0 Truss)

Mission Objectives:

Launch:  
  Launch June 10, 1999 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.6
  Orbits:  
  Duration: 8 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>

Mission Name: STS-100 (100)
  Discovery (28)         
  Pad 39- () (estimated)
  100th Shuttle Mission (estimated)
  xxth Flight OV-105 (estimated)

Crew:

Milestones:
     OPF -- 
     VAB -- 
     PAD -- 

Payload:
  Space Station Assembly Flight SSUF-2 (MPLM,MBS)

Mission Objectives:

Launch:  
  Launch August 5, 1999 (ESTIMATED).  

Orbit:
  Altitude:    
  Inclination: 51.6
  Orbits:  
  Duration: 7 days,  hours, minutes,  seconds. (Estimated)
  Distance:  miles

Hardware:
  SRB: 
  SRM:
  ET :  
  MLP : 
  SSME-1: SN-
  SSME-2: SN-
  SSME-3: SN-

Landing:  
  KSC (estimated)

Mission Highlights:

<end of mission>