MAY 2009 CONTENTS i

CONTENTS 

Section Page

STS-125 MISSION OVERVIEW................................................................................................ 1

SPACE SHUTTLE ENDEAVOUR (STS-400) TO THE RESCUE – IF REQUIRED ........................... 11

STS-125 TIMELINE OVERVIEW ............................................................................................... 17

MISSION PROFILE................................................................................................................... 19

HST SERVICING MISSION PRIORITIES .................................................................................. 21

HUBBLE SPACE TELESCOPE HISTORY .................................................................................... 23

FLIGHT CONTROL .................................................................................................................... 33

STS-125 ATLANTIS CREW ...................................................................................................... 35

PAYLOAD OVERVIEW .............................................................................................................. 

HUBBLE SERVICING MISSION PAYLOAD BAY HARDWARE ................................................................... 

FLIGHT SUPPORT SYSTEM (FSS).........................................................................................................

SOFT CAPTURE AND RENDEZVOUS SYSTEM (SCRS) ............................................................................

SUPER LIGHTWEIGHT INTERCHANGEABLE CARRIER (SLIC) ................................................................

ORBITAL REPLACEMENT UNIT CARRIER .............................................................................................. 

MULTI-USE LIGHTWEIGHT EQUIPMENT CARRIER ................................................................................ 

45

4 5

 45

 45

 47

4 8

4 9

RENDEZVOUS & DOCKING....................................................................................................... 69

SPACEWALKS ......................................................................................................................... 73

SM4 FACILITIES ..................................................................................................................... 83

SHUTTLE REFERENCE DATA .................................................................................................... 87
Section Page

ii CONTENTS MAY 2009

LAUNCH AND LANDING ........................................................................................................... 105

LAUNCH............................................................................................................................................... 105

ABORT-TO-ORBIT................................................................................................................................ 105

TRANSATLANTIC ABORT LANDING ..................................................................................................... . 105

RETURN-TO-LAUNCH-SITE................................................................................................................... 105

ABORT ONCE AROUND ......................................................................................................................... 105

LANDING ............................................................................................................................................. 105

MEDIA ASSISTANCE ............................................................................................................... 113

PUBLIC AFFAIRS CONTACTS .................................................................................................. 115

  

  

  
MAY 2009 MISSION OVERVIEW 1

STS-125 MISSION OVERVIEW 

From the left are astronauts Mike Massimino, Michael Good, both mission specialists;  

Gregory C. Johnson, pilot; Scott Altman, commander; Megan McArthur, John Grunsfeld and

Andrew Feustel, all mission specialists.

The STS‐125 mission of space shuttle Atlantis is

scheduled for launch at 2:01 p.m. EDT on

Monday, May 11, from Launch Complex 39A  

at NASA’s Kennedy Space Center, Fla.  

Atlantis’ crew will service the Hubble Space

Telescope for the fifth and final time.

Nineteen years since its launch in April 1990,

Hubble’s view of the universe again will be

dramatically improved with the addition of two

new science instruments, the repair of two

others, and the replacement of other hardware

that will extend the telescope’s life into the next

decade.

The mission will be commanded by retired

Navy Capt. Scott Altman with retired Navy

Capt. Gregory C. Johnson serving as pilot.  

Megan McArthur is the flight engineer.    The

remaining four mission specialists will pair off

in teams for the five spacewalks.    They are

Andrew Feustel, Air Force Col. Michael Good,

John Grunsfeld, and Mike Massimino.
2 MISSION OVERVIEW MAY 2009

This graphic depicts the location of the STS‐125 payload hardware.

Altman will make his fourth flight, Grunsfeld

his fifth and Massimino his second.   Their last

mission was together on the fourth Hubble

servicing mission, STS‐109, in March 2002.  The

other four crew members are rookies.  

Grunsfeld will make his third consecutive visit

to Hubble, having performed five spacewalks

on his previous missions.

On STS‐125, Grunsfeld and Feustel will team  

on the odd‐numbered spacewalks, while

Massimino and Good are paired on spacewalks

two and four.

Identifying the Spacewalkers:

John Grunsfeld – Solid red stripes

Drew Feustel – No markings (solid white suit)

Mike Massimino – Broken horizontal red stripes

Michael Good – Diagonal red stripes (barber pole)

After launch, the crew will oversee the

checkout of the robotic arm, which will see

extensive action throughout the mission to

position spacewalkers in close proximity to

worksites.  The arm also will be used to survey

the outside surfaces of Atlantis’ crew cabin.

Additionally, the robotic arm will be used on

the second day of the flight to inspect the

shuttle’s sensitive thermal protection system

using the Orbiter Boom Sensor System.    The

boom includes sensors that can detect any

significant damage that may have occurred

during the launch and climb to orbit.  Imagery

experts in Mission Control, Houston, will

evaluate that data in near real‐time, to

determine the health of the orbiter’s thermal

protection system.    The boom is tucked along

the right sill of the payload bay, which also

houses the rest of the mission’s science

instruments, protective canisters and hardware.
MAY 2009 MISSION OVERVIEW 3

Astronaut John Grunsfeld, STS‐125 mission specialist, dons a training version of the

Extravehicular Mobility Unit (EMU) spacesuit before being submerged in the waters

of the Neutral Buoyancy Laboratory (NBL) near the Johnson Space Center.  Astronauts

Gregory C. Johnson (left) and Mike Massimino assist Grunsfeld.

On Flight Day Three Atlantis will arrive within

35 feet of the telescope, at an altitude of about

350 statute miles.    McArthur will carefully

extend the robotic arm to capture a grapple

fixture on the telescope.  She then will carefully

place Hubble atop its Flight Support System, or

FSS, in the back end of the shuttle’s payload

bay.

The FSS serves as a high‐tech “lazy Susan” that

can be rotated and tilted to present the desired

part of the telescope forward for easy access by

spacewalkers, and to offer the best viewing

angles for cameras and crew members inside

Atlantis.    It also provides all electrical and

mechanical interfaces between the shuttle and

the telescope.

With Atlantis’ payload bay essentially serving

as a giant tool box, the stage is set for the first  

of five spacewalks, known as Extravehicular

Activity, or EVA, on consecutive days

beginning on Flight Day Four.  Each spacewalk

is scheduled to last about 6 1/2 hours.

Since almost every part of Hubble was

designed to be repaired and upgraded by

astronauts, training has focused on actual

hardware at NASA’s Goddard Space Flight

Center, Greenbelt, Md., and underwater

mockups at the Johnson Space Center in

Houston, where timelines have been refined for

each day’s scheduled work.
4 MISSION OVERVIEW MAY 2009

The actual servicing of Hubble will begin on 

Flight Day Four with the first EVA. Grunsfeld, 

joined by Feustel initially, will focus on 

swapping the current Wide Field Planetary 

Camera 2 with the like-sized Wide Field 

Camera 3, which will extend Hubble’s 

capability not only by seeing deeper into the 

universe, but also by providing wide-field 

imagery in all three regions of the spectrum – 

ultraviolet, visible and near infrared. It is this 

wide-field “panchromatic” coverage that makes 

WFC3 so unique. The new instrument has a 

mass of 900 pounds and measures 26 inches 

high, 74 inches wide, and 87 inches long. 

The next task has Grunsfeld and Feustel 

swapping the Science Instrument Command 

and Data Handling (SI C&DH) system in 

Bay 10 with a ground spare called into service 

when the in-orbit unit’s “A” side suffered 

a permanent electronic failure in late 

September 2008. The unit provides command 

capability to Hubble’s science instruments 

from the ground and sends data back. Its 

criticality dictated a slight shuffle to the 

spacewalk plan to place the removal and 

replacement of the SI C&DH as the servicing 

mission’s second major task. 

The first spacewalk will wrap up with a 

forward-looking task requiring installation of a 

Soft Capture and Rendezvous System, or SCRS, 

which will enable the future rendezvous, 

capture, and safe disposal of Hubble by either a 

crewed or robotic mission. 

Comprised of the Soft Capture Mechanism, or 

SCM, and the Relative Navigation System, or 

RNS, the SCRS will mount underneath the 

telescope, using a Low Impact Docking System, 

or LIDS, interface. LIDS is designed to be 

compatible with the rendezvous and docking 

systems that will be used on the nextgeneration space transportation vehicle. 

The SCM is about 72 inches in diameter and 

24 inches high and will be attached to the 

telescope by three sets of jaws that clamp onto 

the existing berthing pins on Hubble’s aft 

bulkhead. 

Alternating EVA days, Massimino and Good 

will take their turn on Flight Day Five, focusing 

on the removal and replacement of three pairs 

of gyroscopes known as Rate Sensor Units, or 

RSUs. In concert with star trackers and Fine 

Guidance Sensors (FGS), the RSUs help point 

the telescope precisely for its science 

observations. 

EVA 2 will end with the swap out of the first of 

two battery modules behind an equipment bay 

directly above the WFC3 location. Each module 

weighs 460 pounds and measures 36 inches 

long, 32 inches wide, and 11 inches high and 

contains three batteries. Each nickel hydrogen 

battery weighs 125 pounds and provides all the 

electrical power to support Hubble operations 

during the night portion of its orbit. The 

second battery module will be installed during 

the fifth and final EVA. 

Designed to last only five years, Hubble’s 

batteries have lasted more than 13 years beyond 

their design life, longer than those in any other 

spacecraft located in low Earth orbit. 
MAY 2009 MISSION OVERVIEW 5

Installation of the second new science 

instrument, the Cosmic Origins Spectrograph, 

or COS, will kick off the third spacewalk by 

Grunsfeld and Feustel on Flight Day Six. The 

size of a phone booth, COS will effectively 

restore spectroscopy to Hubble’s scientific 

arsenal. It will replace the Corrective Optics 

Space Telescope Axial Replacement, or 

COSTAR, instrument that corrected Hubble’s 

vision during the first servicing mission 

15 years ago. COS weighs 851 pounds and 

measures 86 inches long, 35 inches wide, and 

35 inches high. 

COSTAR included an ingenious design of small 

mirrors on deployable arms that provided 

corrected light beams to the first generation of 

Hubble instruments in 1993. With all scientific 

instruments designed on the ground to 

compensate for the primary mirror’s “spherical 

aberration,” COSTAR is no longer needed and 

will be placed in a protective canister for its 

return to Earth. 

With the COS task completed, Grunsfeld and 

Feustel will turn their attention to one of the 

more delicate tasks of the mission, the 

restoration of the power supply for the 

Advanced Camera for Surveys, or ACS, which 

has been inoperable since January 2007, when 

its backup power supply system failed. 
6 MISSION OVERVIEW MAY 2009

While seated at the commander’s station, astronaut Scott Altman, STS-125 commander, 

participates in a post insertion/de-orbit training session in the crew compartment trainer (CCT-2) 

in the Space Vehicle Mockup Facility at Johnson Space Center. 

Repairing the ACS power supply will begin by 

preparing the worksite for removal and 

replacement of the failed circuit boards. This 

requires first removing 36 screws from the 

electronics access panel using a specially 

designed “fastener capture plate” that will 

prevent loss of the tiny screws after removal. 

When all of the screws have been removed, the 

entire capture plate can be released as one unit, 

safely taking the access panel and screws with 

it. 

With the ACS power failure likely confined to 

the instrument’s low-voltage power supply, a 

direct repair of that subsystem would require 

too much time for the spacewalk, so engineers 

devised a plan to replace the entire electronics 

box, which will be powered by a separate 

low-voltage power supply. The replacement 

power supply draws power from the Advanced 

Camera for Surveys’ primary power connectors 

via an astronaut-installed splitter cable. 

If careful removal of 36 screws weren’t enough, 

the fourth spacewalk on Flight Day Seven will 

arguably set the bar higher for access panel 

removal when Massimino and Good focus on 

the repair of the Space Telescope Imaging 

Spectrograph’s, or STIS, power supply system. 

They will begin by attaching another fastener 

capture plate to secure 117 screws, so they will 

not have to capture them with their pressurized 

gloved hands. 
MAY 2009 MISSION OVERVIEW 7

Astronaut Megan McArthur, STS-125 mission specialist, dons a training version of her 

shuttle launch and entry suit in preparation for a training session in the Space Vehicle Mockup 

Facility at Johnson Space Center. United Space Alliance (USA) suit technician Cody McNeil 

assists McArthur. 

To repair STIS, astronauts will replace a 

low-voltage power supply board, which 

contains a failed power converter. The repair is 

straightforward, but intricate, and Hubble 

engineers have designed special tools to restore 

one of two fully redundant electronic chains 

of the instrument. Due to this power supply 

failure, STIS has been in “safe mode” since 

August 2004. 

Once they have gained access behind the panel, 

the next challenge will be grasping the failed 

circuit boards for removal. A specially 

designed card extraction tool will allow the 

astronauts to more easily grab and remove the 

circuit boards, using large handles made 

specifically for their gloves. The astronauts 

will remove the failed power supply card and 

click in the new one, much like replacing a 

circuit board on a computer. 

A new, simplified panel then will be installed 

over the open electronics cavity, only this time 

117 fasteners will not be required because the 

new panel fits securely in place by throwing 

only two hand-friendly levers into place. 

The fourth spacewalk will conclude with the 

removal of some temporary thermal insulation 

on the outside of an equipment bay, and 

installation of a more permanent thermal 

protection blanket known as New Outer 

Blanket Layer, or NOBL. 

The fifth and final spacewalk planned for 

Hubble servicing will begin on Flight Day Eight 

with Grunsfeld and Feustel installing the 

second battery group replacement in an 

equipment bay above the Wide Field Camera 2 

and next to the compartment where the first 

battery set was installed on EVA 2. 
8 MISSION OVERVIEW MAY 2009

This image depicts the release of the Hubble Space Telescope on Flight Day 9. 

The two astronauts then will remove and 

replace one of the three Fine Guidance Sensors, 

FGS-2, used to provide pointing information for 

the spacecraft. The sensors also serve as a 

scientific instrument for determining the 

precise position and motion of stars, known as 

astrometry. 

The three Fine Guidance Sensors can hold the 

telescope steady for scientific observations over 

long periods of time. The system serves as the 

telescope’s pointing control system and has a 

precision comparable to being able to hold a 

laser beam focused on a dime 200 miles away, 

the distance from Washington D.C. to New 

York City. 

The refurbished and improved FGS previously 

had been returned on the third servicing 

mission in December 1999. This refurbished 

unit has an enhanced in-orbit alignment 

capability over the original FGS design. It 

weighs 478 pounds and measures 5.5 feet long, 

4 feet wide, and 2 feet high. 

Grunsfeld and Feustel’s last task before closing 

up the telescope for good will be to remove and 

replace at least one additional thermal blanket 

(NOBL) protecting Hubble’s electronics. 
MAY 2009 MISSION OVERVIEW 9

After the work on Hubble is completed, Altman

and Johnson will oversee Atlantis’ reboost of

the telescope to a higher altitude, ensuring it

will survive the tug of Earth’s gravity for the

remainder of its operational lifetime.    A final

decision on how much altitude will be gained

by the reboost will be dependent on Atlantis’

available propellant.

Hubble Space Telescope science observations

are expected to resume approximately three

weeks after the shuttle departs.

With servicing completed, the stage will be set

for release of Hubble from the shuttle’s robotic

arm for the final time on Flight Day Nine.  

Before release, the telescope’s new batteries will

be fully charged by placing Atlantis into a

position allowing Hubble’s solar arrays “sun

time.”    The aperture door will be opened and

the high‐gain antennas once again will be

deployed.

McArthur will release the grapple fixture as

Altman and Johnson guide Atlantis carefully

away, before subtle thruster firings place the

shuttle a safe distance from Hubble.

Later that day, attention will turn to surveys of

Atlantis’ thermal protection system, including

its wing leading edge panels, nose cap and

underside tiles.   Imagery experts will evaluate

the data to determine the health of the thermal

protection system.

A crew off‐duty day on Flight Day 10 will be

followed on Flight Day 11 by the standard  

day‐before‐landing checkout of landing

systems, including the flight control system and

reaction control system thrusters and

accompanying electronics.

Once Atlantis is cleared for entry following the

late inspection imagery review, space shuttle

Endeavour, on standby at Launch Pad 39B for

service as a rescue vehicle, will be released for

processing toward its mission to the

International Space Station in June.    Kennedy

ground operations will prepare it for relocation

to pad 39A about a week after Atlantis returns

to Earth.

STS‐125 will be the 30th for Atlantis, following

its previous flight to the International Space

Station in February 2008 to deliver the

European Space Agency’s Columbus science

laboratory.   This will be the 126th flight in the

history of the shuttle program.    Landing is

scheduled at about 11:41 a.m. EDT on May 22,

at the Kennedy Space Center.
10 MISSION OVERVIEW MAY 2009

The space shuttle Atlantis, backdropped over a colorful Earth, is pictured after it 

undocked from the International Space Station in 2006. 
MAY 2009 STS-400 11

SPACE SHUTTLE ENDEAVOUR (STS-400) TO THE 

RESCUE – IF REQUIRED 

Unlike shuttle missions to the International

Space Station, which can sustain a stranded

crew for up to 90 days, space shuttle Atlantis’

flight to the Hubble Space Telescope offers no

additional supplies other than those carried

aboard the orbiter.

Since Hubble is in a different orbit than the

space station, a second shuttle – Endeavour –

sits on standby at Launch Complex 39B to serve

as a rescue vehicle in the unlikely event Atlantis

is unable to return home safely.   It will be the

first time since October 2008 that shuttles have

simultaneously occupied both launch pads.

While Endeavour is readied for launch,

Atlantis’ crew would conserve as much power

and oxygen on board to extend its life for as

much as 25 days.
12 STS-400 MAY 2009

Designated STS‐400, the rescue mission of

Endeavour would launch with four astronauts

– the flight deck crew from the STS‐126 mission.  

Chris Ferguson would be the commander, Eric

Boe would be pilot, and Shane Kimbrough and

Steve Bowen would be mission specialists.  The

middeck would be reserved for the return of

the seven Atlantis crew members.

Following launch, Endeavour’s crew will spend

launch day checking out the rendezvous

equipment to be used the next day as well as

testing the robotic arm for the grapple of

Atlantis.

Endeavour would rendezvous from beneath

Atlantis approximately 23 hours after launch

with pilot Boe using the robot arm to grapple a

fixture on the forward end of the Orbiter Boom

and Sensor System mounted along the right

side of Atlantis’ payload bay.

The grapple occurs with the payload bay of

each vehicle pointed toward each other with

the orbiters perpendicular to one another for

clearance.    The distance between the two at

grapple would be about 24 feet.
MAY 2009 STS-400 13

After capture, a 90‐degree yaw of the arm will

put the vehicles payload bay‐to‐payload bay

providing the most stable attitude and position

relative to the Earth’s location ahead of the

three spacewalks by Atlantis’ crew to relocate

to Endeavour.

The third day of the mission will be dedicated

to set up of a translation path from Atlantis to

Endeavour and the start of crew transfer.   

John Grunsfeld and Andrew Feustel will string

a cable along the length of the robot arm  

to serve as the translation path and  

Megan McArthur will be moved to Endeavour.  

She will be followed aboard Endeavour by

Feustel, then Grunsfeld who will spend the

night on Endeavour.    The first spacewalk is

scheduled to last 4 hours, 50 minutes.

On the fourth day of the flight Grunsfeld will

suit up and head back to Atlantis and assist

Mike Massimino and Gregory C. Johnson  

with translation back to Endeavour.    The

second spacewalk is planned to last just under

two hours leaving Grunsfeld and Johnson on

Endeavour.

The third spacewalk occurs the same day with

Massimino moving back to Atlantis to assist

Michael Good and Scott Altman as they

prepare to depart Atlantis for Endeavour.  The

final spacewalk is budgeted for about

two hours, 30 minutes.    Prior to leaving

Atlantis, Altman would reconfigure the vehicle

so that it can be ground commanded through a

deorbit disposal burn.
14 STS-400 MAY 2009

With all seven STS‐125 crew members aboard,

Endeavour’s pilot Greg H. Johnson will release

the grapple fixture on Atlantis’ boom ending

the rescue operation.

The following day focuses on checkout of

Endeavour’s thermal protection system using

its robot arm and boom extension and sensor

package.    The “new” crew members from

Atlantis will perform the checkout.

The crew focuses on cabin stowage on the sixth

day in preparation for return home.

Traditional day‐before‐landing activities and

systems checkouts occur on the seventh day

with deorbit and landing on the eighth day.  

Atlantis’ seven astronauts will be seated on the

middeck for the return.

Though extremely unlikely to be needed, the

Space Shuttle Program decided long ago to

have a “launch on need” capability for the

remaining shuttle missions, including this flight

to the Hubble Space Telescope.

Once Endeavour is released from its rescue

obligation, it will be relocated from pad 39B to

39A for launch on its scheduled mission to

deliver the final components of the Japan

Aerospace Exploration Agency’s Kibo science

laboratory to the International Space Station.  

That flight (STS‐127) is scheduled for launch on

June 13.
MAY 2009 STS-400 15

Endeavour Crew

Chris Ferguson – Commander

Eric Boe – Pilot

Shane Kimbrough – Mission Specialist 1

Steve Bowen – Mission Specialist 2/Flight Engineer

Mission Timeline

Flight Day 1

• Launch

• Robot arm checkout

• Rendezvous tools checkout

Flight Day 2

• Rendezvous

• Robot arm grapples fixture on Atlantis’

OBSS

Flight Day 3

• First spacewalk (4 hours, 50 minutes)

− Grunsfeld and Feustel with McArthur to

Endeavour
16 STS-400 MAY 2009

Flight Day 4

• Second spacewalk (1 hour, 45 minutes)

− Grunsfeld to Atlantis

− Grunsfeld and Massimino with Johnson

to Endeavour

− Massimino back to Atlantis

• Third spacewalk (2 hours, 30 minutes)

− Massimino with Good and Altman to

Endeavour

• Release of Atlantis

• Separation burn

Flight Day 5

• OBSS survey of Endeavour’s Thermal

Protection System

• Crew off duty

Flight Day 6

• Crew cabin survey

• Crew off duty

Flight Day 7

• Flight Control System checkout

• Reaction Control System hotfire test

• Entry seating setup

• Cabin Stow

Flight Day 8

• Deorbit

• Landing
MAY 2009 TIMELINE OVERVIEW 17

STS-125 TIMELINE OVERVIEW 

Flight Day 1 

• Launch 

• Payload Bay Door Opening 

• Ku-Band Antenna Deployment 

• Shuttle Robotic Arm Activation 

• Space Support Equipment Checkout 

• Umbilical Well and Handheld External 

Tank Video and Stills Downlink 

Flight Day 2 

• Atlantis Thermal Protection System Survey 

with Orbiter Boom Sensor System 

• Extravehicular Mobility Unit Checkout 

• Payload Bay Flight Support System 

Preparations 

• Rendezvous Tools Checkout 

• HST Aperture Door Closure 

• HST Maneuver to Rendezvous and Grapple 

Attitude 

• HST High Gain Antenna Retraction 

Flight Day 3 

• Rendezvous with the Hubble Space 

Telescope 

• HST Solar Arrays Positioned for Grapple 

• HST Grapple and Berth on Flight Support 

System 

• Shuttle Robotic Arm Survey of HST 

• EVA 1 Procedure Review 

Flight Day 4 

• EVA 1 by Grunsfeld and Feustel (Wide 

Field Camera III Installation, Science 

Instrument Command and Data Handling 

Computer, Soft Capture Mechanism 

Installation and Latch Over Centerline Kit 

Installation) 

• Wide Field Camera III Aliveness Test and 

Checkout 

• SI C&DH Aliveness Checkout 

• Bay 3 Battery Checkout 

• EVA 2 Procedure Review 

Flight Day 5 

• EVA 2 by Massimino and Good (Rate 

Sensor Unit Changeout and Bay 2 Battery 

Changeout) 

• Bay 2 Battery Checkout 

• Rate Sensor Unit Checkout 

• EVA 3 Procedure Review 

Flight Day 6 

• EVA 3 by Grunsfeld and Feustel (Cosmic 

Origins Spectrograph replaces the 

Corrective Optics Space Telescope Axial 

Replacement known as COSTAR and the 

repair to the Advanced Camera for Surveys) 

• Cosmic Origins Spectrograph Checkout 

• ASC Checkout 

• EVA 4 Procedure Review 
18 TIMELINE OVERVIEW MAY 2009

Flight Day 7 

• EVA 4 by Massimino and Good (Space 

Telescope Imaging Spectrograph 

refurbishment and New Outer Layer 

Blanket replacement over Bay 8) 

• Space Telescope Imaging Spectrograph 

Checkout 

• EVA 5 Procedure Review 

Flight Day 8 

• EVA 5 by Grunsfeld and Feustel (Bay 3 

Battery Changeout, Fine Guidance Sensor-2 

Replacement and New Outer Layer Blanket 

replacement over Bay 5) 

• Fine Guidance Sensor-2 Checkout 

• Bay 3 Battery Checkout 

• Advanced Camera for Surveys and Wide 

Field Camera III Combined Checkout 

• High Gain Antenna Deployment 

• HST Reboost, if propellant permits 

• Rendezvous Tools Checkout 

Flight Day 9 

• HST Aperture Door Opening 

• Atlantis/HST Maneuver to Release Attitude 

• HST Release 

• Atlantis Separation Maneuver 

• Flight Support System Stowage in Payload 

Bay 

• OBSS Unberth 

• OBSS Late Inspection of Atlantis Thermal 

Protection System 

Flight Day 10 

• Crew Off Duty Time 

• Crew News Conference 

• Atlantis/ISS Ship-to-Ship Call 

Flight Day 11 

• Flight Control System Checkout 

• Reaction Control System Hot-Fire Test 

• Cabin Stowage 

• Ku-Band Antenna Stowage 

Flight Day 12 

• Deorbit Preparations 

• Payload Bay Door Closing 

• Deorbit Burn 

• Kennedy Space Center Landing 
MAY 2009 MISSION PROFILE 19

MISSION PROFILE 

CREW 

Commander: Scott Altman  

Pilot: Gregory C. Johnson

Mission Specialist 1: Michael Good

Mission Specialist 2: Megan McArthur

Mission Specialist 3: John Grunsfeld

Mission Specialist 4: Mike Massimino

Mission Specialist 5: Andrew Feustel

LAUNCH 

Orbiter: Atlantis (OV‐104)

Launch Site: Kennedy Space Center

Launch Pad 39A

Launch Date: May 11, 2009

Launch Time: 2:01 p.m. EDT

Launch Window: 42 minutes

(approximately)

Altitude: 297 Nautical Miles

(342 miles) Orbital

Insertion; 304 NM

(350 miles) Rendezvous

Inclination: 28.5 Degrees

Duration: 10 Days 20 Hours

27 Minutes

VEHICLE DATA 

Shuttle Liftoff Weight: 4,519,343

pounds

Orbiter/Payload Liftoff Weight: 264,165

pounds

Orbiter/Payload Landing Weight: 226,040

pounds

Software Version: OI‐32

Space Shuttle Main Engines: 

SSME 1: 2059

SSME 2: 2044

SSME 3: 2057

External Tank: ET‐130

SRB Set: BI‐137

RSRM Set: 105

SHUTTLE ABORTS 

Abort Landing Sites 

RTLS: Kennedy Space Center Shuttle

Landing Facility

TAL: Primary –Moron, Spain

AOA: Primary – Edwards Air Force Base

LANDING 

Landing Date: May 22, 2009

Landing Time: 11:41 a.m. EDT

Primary landing Site: Kennedy Space Center

Shuttle Landing Facility

PAYLOADS 

Hubble Space Telescope Servicing Mission

(HST SM4)
20 MISSION PROFILE MAY 2009

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MAY 2009 MISSION PRIORITIES 21

HST SERVICING MISSION PRIORITIES 

1. Three Rate Sensor Unit (gyroscope) removal 

and replacement 

2. Wide Field Camera 3 installed in place of 

Wide Field Planetary Camera 2 

3. Science Instrument Command & Data 

Handling System swap out 

4. Cosmic Origins Spectrograph installation 

5. Battery Module replacement installation 

(Bays 2 and 3) 

6. Fine Guidance Sensor 2 removal and 

replacement 

7. Remaining instrument repair 

8. Space Telescope Imaging Spectrograph 

power supply system repair, or restore 

power supply for the Advanced Camera for 

Surveys *

9. New Outer Blanket Layer installation 

(Bays 8, 5 & 7) 

10. Soft Capture Mechanism installation 

11. Reboost Hubble Space Telescope altitude 

* Choice of first instrument repair will be prioritized 

based on spacewalk efficiency and mission 

replanning scenarios
22 MISSION PRIORITIES MAY 2009

HST SERVICING MISSION SUCCESS CRITERIA 

• Minimum Mission Success 

− Two Rate Sensor Units (four 

gyroscopes) 

− Wide Field Camera 3 

− Science Instrument Command & Data 

Handling system 

− Cosmic Origins Spectrograph 

− Bay 2 & 3 Battery Module replacements 

(six new batteries) 

• Full Mission Success 

− Three Rate Sensor Units (five 

gyroscopes) 

− Wide Field Camera 3 

− Science Instrument Command & Data 

Handling system 

− Cosmic Origins Spectrograph 

− Bay 2 & 3 Battery Module replacements 

(six new batteries) 

− Space Telescope Imaging Spectrograph 

repair, or Advanced Camera for Surveys 

repair 

− Fine Guidance Sensor 2 
MAY 2009 HST HISTORY 23

HUBBLE SPACE TELESCOPE HISTORY 

The Hubble Space Telescope (HST) heads back toward its normal routine, after 

a week of servicing and upgrading by the STS-109 astronaut crew in 2002. 

HUBBLE PROGRAM 

Launched in April 1990 and poised for many 

more years of trailblazing science ranging from 

our own solar system to the edge of the 

observable universe, NASA’s Hubble Space 

Telescope is fulfilling the hopes astronomers 

have long held for a large, optically superb 

telescope orbiting above the Earth’s distorting 

atmosphere and providing uniquely clear and 

deep views of the cosmos. 

The only one of NASA’s four “Great 

Observatories” (Hubble, Compton Gamma-Ray 

Observatory, Chandra X-Ray Observatory, and 

Spitzer Space Telescope) that is serviceable by 

space shuttle astronauts, Hubble has seen its 

capabilities grow immensely in its 18 historic 

years of operation. This has been the direct 

result of the installation of new, cutting-edge 

scientific instruments and more powerful 

engineering components. Replacement of 

aging or failed parts has been an important 

aspect of servicing and has been responsible for 

the telescope’s longevity. 

All of the Great Observatories have a particular 

range of light or electromagnetic radiation to 

which they are designed and are sensitive. 

Hubble’s domain extends from the ultraviolet, 

through the visible (to which human eyes are 

sensitive), and to the near-infrared. In terms of 

the wavelength of light, Hubble’s coverage 

ranges from 1,200 Angstroms in the ultraviolet 
24 HST HISTORY MAY 2009

(1 Angstrom = 1 hundred-millionth of a 

centimeter) to 2.4 microns (24,000 Angstroms) 

in the near-infrared. Hubble’s UV-to-near-IR 

spectral range is a key piece of “astronomical 

real estate” – a dominant range of wavelengths 

emitted by stars and galaxies – and Hubble 

takes advantage of this access with both 

imaging and spectroscopy. 

Compared to ground-based telescopes, Hubble 

is not particularly large. With a primary mirror 

diameter of 2.4 meters (94.5 inches), Hubble 

would at most be considered a medium-size 

telescope on the ground. However, the 

combination of its precision optics, location 

above the atmosphere, state-of-the-art 

instrumentation, and unprecedented pointing 

stability and control, allows Hubble to more 

than make up for its lack of size. The most 

detailed look at the farthest known galaxies in 

the universe has been obtained by imaging 

from the Hubble Space Telescope. 

Spectroscopically, Hubble has detected several 

atomic constituents in the atmosphere of a 

planet outside our solar system, an enormously 

difficult measurement and a first in this critical 

and growing field whose ultimate aim is to look 

for places elsewhere in the universe where the 

conditions for life exist. 

On Jan. 16, 2004, NASA Administrator 

Sean O’Keefe announced the cancellation of the 

final scheduled servicing mission to Hubble. 

The review board studying the shuttle 

Columbia disaster recommended that all future 

space shuttle missions fly in orbits that allow 

them to reach the International Space Station in 

case of an emergency. The orbit a shuttle 

would need to follow to service Hubble would 

not allow the shuttle to get to the station. 

However, during a meeting with agency 

employees at NASA’s Goddard Space Flight 

Center on Oct. 31, 2006, NASA Administrator 

Michael Griffin announced there would indeed 

be a fifth and final servicing mission to Hubble. 

In making the announcement, Griffin said, “We 

have conducted a detailed analysis of the 

performance and procedures necessary to carry 

out a successful Hubble repair mission over the 

course of the last three shuttle missions. What 

we have learned has convinced us that we are 

able to conduct a safe and effective servicing 

mission to Hubble. While there is an inherent 

risk in all spaceflight activities, the desire to 

preserve a truly international asset like the 

Hubble Space Telescope makes doing this 

mission the right course of action.” 

Previous Servicing Missions 

The STS-125/HST-SM4 mission was originally 

planned for an Oct. 14, 2008 launch. Space 

shuttle Atlantis and her 22,000 pounds of 

Hubble cargo were in the final days of launch 

preparations, when the “A” side of the Science 

Instrument Command and Data Handling 

(SI C&DH) system suffered a permanent 

electronic failure on Sept. 27, 2008. The 

SI C&DH provides all of the electronics to 

command Hubble’s science instruments from 

the ground and to flow science and engineering 

data back to the ground. Because this system is 

such a critical part of Hubble’s science 

capability, the mission was postponed in order 

to allow engineers enough time to prepare the 

spare SI C&DH for inclusion into the servicing 

mission. Meanwhile, in order to restore science 

operations to the orbiting telescope, flight 

controllers on the ground successfully switched 

to the “B” side of the SI C&DH electronics and 

several additional spacecraft data system 

modules. 
MAY 2009 HST HISTORY 25

Servicing Mission 1, December 1993: The 

primary goal of Servicing Mission 1 was to 

restore Hubble’s vision. Because Hubble’s 

primary mirror was incorrectly shaped, the 

telescope could not focus all the light from 

an object to a single sharp point. Instead, it 

saw a fuzzy halo around objects it observed. 

Astronauts on space shuttle Endeavour’s 

STS-61 mission spent five days tuning it up. 

They installed two new devices – the Wide 

Field and Planetary Camera 2 and the 

Corrective Optics Space Telescope Axial 

Replacement – to compensate for the primary 

mirror’s incorrect shape. Astronauts also 

installed new solar arrays, to reduce the jitter 

caused by excessive flexing of the solar panels 

during the telescope’s orbital transition from 

cold darkness into warm daylight, and new 

gyroscopes to help point and track the 

telescope, along with fuse plugs and electronic 

units. 

Servicing Mission 2, February 1997: During 

the 10-day mission (STS-82), astronauts aboard 

the space shuttle Discovery installed two 

technologically advanced instruments. The 

Near Infrared Camera and Multi-Object 

Spectrometer (NICMOS) enabled Hubble to 

observe infrared wavelengths, crucial for 

viewing very distant optical sources that have 

lost energy traveling across most of the visible 

universe and now radiate in the infrared band. 

The second instrument, the Space Telescope 

Imaging Spectrograph (STIS), could take 

detailed pictures of celestial objects and hunt 

for black holes. Both instruments featured 

technology that wasn’t available when 

scientists designed and built the original 

Hubble instruments in the late 1970s. 

Astronauts also installed a refurbished Fine 

Guidance Sensor, one of three essential 

instruments used to keep Hubble steady while 

viewing objects and to calculate celestial 

distances; a Solid State Recorder to replace one 

of Hubble’s data recorders; and a refurbished, 

spare Reaction Wheel Assembly, part of the 

Pointing Control Subsystem. 

Servicing Mission 3A, December 1999: NASA 

decided to split the third servicing mission into 

two parts, SM3A and SM3B, after the third of 

Hubble’s six gyroscopes failed. Hubble 

normally needs three gyroscopes to observe a 

target. Astronauts aboard space shuttle 

Discovery (STS-103) replaced all six gyroscopes, 

as well as one of Hubble’s three fine guidance 

sensors that are used to keep Hubble steady 

while viewing objects. The astronauts also 

installed a transmitter, an advanced central 

computer, a digital data recorder, an electronics 

enhancement kit, battery improvement kits and 

new outer layers of thermal protection. Shortly 

before the 3A mission, Hubble was placed into 

“safe-mode” after a fourth gyroscope failed 

unexpectedly. In safe-mode Hubble is in a sort 

of protective hibernation and cannot observe 

objects. 

Servicing Mission 3B, March 2002: Astronauts 

aboard space shuttle Columbia (STS-109) 

installed several new instruments on Hubble 

that vastly improved the observatory’s 

capability. Astronauts performed five 

spacewalks. Their principal task was to install 

the Advanced Camera for Surveys (ACS). With 

its wide field of view, sharp image quality and 

enhanced sensitivity, ACS could collect data 

10 times faster than the Wide Field and 

Planetary Camera 2, the telescope’s earlier 

surveying instrument. The ACS brought the 

then 12-year-old telescope into the 21st century. 

The ACS was quickly used to capture the most 

distant image of the universe, called the Hubble 

Ultra Deep Field. The 8-year-old solar array 

panels were replaced with smaller rigid ones 
26 HST HISTORY MAY 2009

Astronaut James H. Newman, mission specialist, moves about in the space shuttle Columbia’s 

cargo bay while working in tandem with astronaut Mike Massimino (out of frame), 

mission specialist, during the STS-109 mission’s second day of extravehicular activity (EVA). 

that produce 30 percent more power. 

Astronauts also replaced the outdated Power 

Control Unit, which distributes electricity from 

the solar arrays and batteries to other parts of 

the telescope; and they replaced one of the four 

reaction wheel assemblies that make up 

Hubble’s pointing control system. Another key 

upgrade was the installation of a new cooling 

system for the Near Infrared Camera and 

Multi-Object Spectrometer (NICMOS), down 

since 1999 after depleting its refrigerant. 

Hubble’s infrared vision was restored. 
MAY 2009 HST HISTORY 27

Best of Hubble Science 

As the 12.5-ton Earth-orbiting observatory 

looks into space, unburdened by atmospheric 

distortion, new details about planets, stars and 

galaxies come into crystal clear view. The 

telescope has produced a vast amount of 

information and a steady stream of images that 

have astounded the world’s astronomical 

community and the public as well. It has 

helped confirm some astronomical theories, 

challenged others and often come up with 

complete surprises for which theories do not 

yet exist. 

Hubble provides four basic capabilities: 

• High angular resolution – the ability to 

image fine detail. 

• High sensitivity – the ability to detect very 

faint objects. 

• Ultraviolet performance – the ability to 

produce ultraviolet images and spectra. 

• Infrared performance – the ability to 

produce infrared images and spectra. 

Each year the Space Telescope Science Institute 

(STScI) receives approximately a thousand new 

observing proposals from astronomers around 

the world. Observing cycles are routinely oversubscribed by a factor of six. 

The telescope is extremely popular because it 

allows scientists to get their clearest view ever 

of the cosmos and to obtain information on the 

temperature, density, composition and motion 

of celestial objects by analyzing the radiation 

they emit or absorb. On average 14 scientific 

papers per week, based on Hubble 

observations, are published in scholarly 

journals. Results of Hubble observations are 

presented regularly at meetings of the 

American Astronomical Society and other 

major scientific conferences. 

Although Hubble’s dramatic findings to date 

are too numerous to be described fully, the 

following paragraphs highlight some of the 

significant astronomical discoveries and 

observations in three basic categories: 

• Galaxies and cosmology 

• Formation and evolution of stars and 

planets 

• Earth’s Solar System. 

For further information, visit the STScI Web site 

at http://hubblesite.org/newscenter. 

Galaxies and Cosmology 

Deepest View Ever of the Universe Unveils 

Earliest Galaxies 

http://hubblesite.org/newscenter/archive/releas

es/2004/07

In a tiny patch of sky just one-tenth the 

diameter of the full moon, the Hubble 

Space Telescope revealed an estimated 

10,000 galaxies. Called the Hubble Ultra Deep 

Field (HUDF), the million-second-long 

exposure reveals the first galaxies to emerge 

from the so-called “dark ages,” the time shortly 

after the big bang when the first stars reheated 

the relatively cool and opaque hydrogen and 

helium gas produced in the big bang, making it 

transparent to light. The image offers new 

insights into what types of objects reheated the 

universe long ago leading ultimately to the 

universe as seen today. 
28 HST HISTORY MAY 2009

The sharpest image ever taken of the large “grand design” spiral galaxy M81 released at the 

American Astronomical Society Meeting in Honolulu, Hawaii. This beautiful galaxy is tilted at 

an oblique angle on to our line of sight, giving a bird’s-eye view of the spiral structure. 

The historic view is actually two separate sets 

of images taken by Hubble’s Advanced Camera 

for Surveys (ACS) and the Near Infrared 

Camera and Multi-object Spectrometer 

(NICMOS) and stacked together to form a 

single extremely deep time exposure. The 

resulting composite image, the HUDF, reveals 

galaxies that are too faint to be seen by groundbased telescopes, or even in Hubble’s previous 

faraway looks, called the Hubble Deep Fields 

(HDF’s), taken in 1995 and 1998. In groundbased images, the patch of sky in which the 

galaxies reside is largely empty. Located in the 

constellation Fornax, the region is below the 

constellation Orion. 

The combination of ACS and NICMOS images 

has been used to search for developing galaxies 

that were formed within the first billion years 

after the big bang, which occurred 13.7 billion 

years ago. To date, more than 500 objects have 

been detected in the HUDF that emitted the 

light we see with Hubble when the universe 

was less than one billion years old (at a redshift 

of 6 or greater.). At least one galaxy has been 

detected at a redshift of 7.4. Light from this 
MAY 2009 HST HISTORY 29

object started its journey toward us some 

700 million years after the big bang, when the 

universe was five percent of its current age. A 

key question for HUDF astronomers is in what 

respects the universe appeared different at this 

very early time, when star formation had just 

begun, than it did when the cosmos was 

between one and two billion years old, at which 

time the rate of star formation in the universe 

had dropped to a very low value. 

HUDF observations began Sept. 24, 2003, and 

continued through Jan. 16, 2004. The ACS, 

which is the size of a phone booth, captured 

ancient photons of light that began traversing 

the universe even before Earth existed. Photons 

of light from the very faintest objects arrived at 

a trickle of one photon per minute, compared 

with millions of photons per minute from 

nearer galaxies. 

Evolution of Stars and Planets 

Light Echo from Erupting Star 

http://hubblesite.org/newscenter/archive/releas

es/star/2004/10/

In January 2002, a dull star in an obscure 

constellation suddenly became 600,000 times 

more luminous than our sun, temporarily 

making it one of the brightest stars in our Milky 

Way galaxy. 

The mysterious star has long since faded back 

to obscurity, but Hubble observations of a 

phenomenon called a “light echo” have 

uncovered remarkable new features. These 

details have provided astronomers a CAT-scanlike probe of the three-dimensional structure of 

shells of dust surrounding an aging star. 

Astronomers used the Hubble images to 

determine that the ill-tempered star, called 

V838 Monocerotis (V838 Mon), is about 

20,000 light-years from Earth. The star puts out 

enough energy in a brief flash to illuminate 

surrounding dust. The star presumably ejected 

the illuminated dust shells in previous 

outbursts. Light from the latest outburst travels 

to the dust and then is reflected to Earth. 

Because of this indirect path, the light arrives at 

Earth months after light coming directly toward 

Earth from the star itself. 

The outburst of V838 Mon was somewhat 

similar to that of a nova, a more common stellar 

outburst. A typical nova is a normal star that 

dumps hydrogen onto a compact white-dwarf 

companion star. The hydrogen piles up until it 

spontaneously explodes by nuclear fusion – like 

a titanic hydrogen bomb. This exposes a 

searing stellar core, which has a temperature of 

hundreds of thousands of degrees Fahrenheit. 

By contrast, however, V838 Mon evidently did 

not expel its outer layers. Instead, it grew 

enormously in size, with its surface 

temperature dropping to temperatures not 

much hotter than a light bulb and its color 

becoming extremely red. This behavior of 

ballooning to an immense size but not losing its 

outer layers is very unusual and completely 

unlike an ordinary nova explosion. 

V838 Mon is so unique it may represent a 

transitory stage in a star’s evolution that is 

rarely seen. The star has some similarities to 

highly unstable aging stars called eruptive 

variables, which suddenly and unpredictably 

increase in brightness. 

The circular light-echo feature now has 

expanded to twice the angular size of Jupiter on 

the sky. Astronomers expect that it will 

continue expanding as reflected light from 

farther out in the dust envelope finally arrives 

at Earth. 
30 HST HISTORY MAY 2009

Earth’s Solar System 

Hubble Looks for Possible Moon Resources 

http://hubblesite.org/newscenter/archive/releas

es/2005/29

When Americans return to the moon, they will 

have the Hubble Space Telescope to thank for a 

new class of scientific observations of Earth’s 

nearest celestial neighbor. 

Hubble’s resolution and sensitivity to 

ultraviolet light have allowed it to search for 

important oxygen-bearing minerals on the 

moon. Since the moon does not have a 

breathable atmosphere, minerals such as 

ilmenite (titanium and iron oxide) may be 

critical for a sustained human lunar presence. 

Ilmenite is a potential source of oxygen for 

breathing or powering rockets. 

The new Hubble observations are the first 

high-resolution, ultraviolet images ever 

acquired of the moon. The images provide 

scientists with a new tool to study mineral 

variations within the lunar crust. Such data, in 

combination with other measurements, will 

help ensure the most valuable sites are targeted 

for future robotic and human missions. 

In 2005, Hubble’s Advanced Camera for 

Surveys captured ultraviolet and visible light 

images of known geologically diverse areas on 

the side of the moon nearest Earth. These 

included the Aristarchus impact crater and the 

adjacent Schroter’s Valley, which neither 

humans nor robotic spacecraft have visited. 

Hubble also photographed the Apollo 15 and 

17 landing sites, where astronauts collected 

rock and soil samples in 1971 and 1972. 

Scientists are comparing the properties of the 

rock and soil samples from the Apollo sites 

with the new Hubble images. The telescope’s 

observations of Aristarchus crater and 

Schroter’s Valley will help refine researchers’ 

understanding of the diverse, scientifically 

interesting materials in the region and unravel 

their full resource potential. 

Summary 

Astronauts Steven L. Smith, and 

John Grunsfeld appear as small figures in this 

wide scene photographed during 

extravehicular activity during STS-103 in 1999. 

The Hubble Space Telescope has established 

itself as a premier astronomical observatory 

that continues to make dramatic observations 

and discoveries at the forefront of astronomy. 

Among a long list of achievements: 

• Hubble’s ability to detect faint supernovae 

contributed to the discovery that the 

expansion rate of the universe is 

accelerating, indicating the existence of 

mysterious “dark energy” in space. 

• Observations of Cepheid variable stars in 

nearby galaxies were used to establish the 
MAY 2009 HST HISTORY 31

current expansion rate of the universe to 

better than 10 percent accuracy. 

• The Hubble Ultra Deep Field provided our 

deepest view yet into the universe’s distant 

past, allowing us to reconstruct how 

galaxies evolve and grow by swallowing 

other galaxies. 

• Hubble provided the first direct 

measurements of the three-dimensional 

distribution of Dark Matter in space. 

• Peering into nearby regions of star birth in 

the Milky Way galaxy, Hubble has revealed 

flattened disks of gas and dust that are the 

likely birthplaces of new planets. 

• When sun-like stars end their lives, they 

eject spectacular nebulae. Hubble has 

revealed fantastic and enigmatic details of 

this process 

• Hubble made detailed measurements of a 

Jupiter-sized planet orbiting a nearby star, 

including the first detection of the 

atmosphere of an extrasolar planet. 

• The explosive collision of comet 

Shomaker-Levy/9 with Jupiter gave 

Earthlings a cautionary tale of the danger 

posed by cometary impacts. 

• Hubble observations have shown that 

monster black holes, with masses millions 

to billions times the mass of our sun, inhabit 

the centers of most galaxies 

• Hubble played a key role in determining 

the distances and energies of gamma-ray 

bursts, showing that they are the most 

powerful explosions in the universe other 

than the big bang itself. 

After Servicing Mission 4, the telescope will 

view the universe with significantly expanded 

scientific capabilities from the new Wide Field 

Camera 3 and the new Cosmic Origins 

Spectrograph, as well as the reactivated 

Advanced Camera for Surveys and Space 

Telescope Imaging Spectrograph. These 

additions and the upgrades to Hubble’s 

operating hardware hold the promise of 

momentous discoveries in the years ahead. 
32 HST HISTORY MAY 2009

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MAY 2009 FLIGHT CONTROL 33

FLIGHT CONTROL 

KEY CONSOLE POSITIONS FOR STS-125 

 Flt. Director CAPCOM PAO

Ascent Norm Knight Greg (Box) Johnson 

TBD (Wx) 

Kyle Herring 

Orbit 1 (Lead) Tony Ceccacci Dan Burbank Kyle Herring 

(Lead) 

Orbit 2 Rick LaBrode Alan Poindexter Pat Ryan 

Planning Paul Dye Janice Voss Josh Byerly 

Entry Norm Knight Greg (Box) Johnson 

TBD (Wx) 

Kyle Herring 

Shuttle Team 4 Bryan Lunney N/A N/A 

 

JSC PAO Representative at KSC for Launch – Kylie Clem 

KSC Launch Commentator – George Diller 

KSC Launch Director – Mike Leinbach 

NASA Launch Test Director – Charlie Blackwell-Thompson 
34 FLIGHT CONTROL MAY 2009

KEY CONSOLE POSITIONS FOR STS-400 

 Flt. Director CAPCOM PAO

Ascent Norm Knight Greg (Box) Johnson 

TBD (Wx) 

Kyle Herring 

Orbit 1 (Lead) Paul Dye Steve Robinson Kyle Herring 

(Lead) 

Orbit 2 Mike Sarafin Greg (Box) Johnson Pat Ryan 

Planning Richard Jones Janice Voss Josh Byerly 

Entry Norm Knight Greg (Box) Johnson 

TBD (Wx) 

Kyle Herring 

Shuttle Team 4 Bryan Lunney N/A N/A 

 

JSC PAO Representative at KSC for Launch – TBD 

KSC Launch Commentator – George Diller 

KSC Launch Director – Mike Leinbach 

NASA Launch Test Director – Jeff Spaulding 
MAY 2009 CREW 35

STS-125 ATLANTIS CREW 

This STS-125/SM4 crew patch shows the 

Hubble Space Telescope along with a 

representation of its many scientific discoveries. 

The overall structure and composition of the 

universe is shown in blue and filled with 

planets, stars and galaxies. 

The black background is indicative of the 

mysteries of dark-energy and dark-matter. The 

new instruments to be installed on Hubble 

during this mission, Wide Field Camera-3 and 

the Cosmic Origins Spectrograph, will make 

observations to help understand these unseen 

components that seem to dominate the 

structure of the universe. 

The red border of the patch represents the redshifted glow of the early universe and the limit 

of the Hubble's view into the cosmos. Upon 

completion of STS-125/SM4, the fifth mission to 

service Hubble, the telescope will provide even 

deeper and more detailed views of the 

universe. 

Soaring by the telescope is the space shuttle, 

which initially deployed Hubble and has 

enabled astronauts to continually upgrade the 

telescope, significantly contributing to the 

expansion of human knowledge. 
36 CREW MAY 2009

These seven astronauts take a break from training to pose for the STS-125/SM4 crew portrait. 

From the left are astronauts Mike Massimino, Michael Good, both mission specialists; 

Gregory C. Johnson, pilot; Scott Altman, commander; Megan McArthur, 

John Grunsfeld and Andrew Feustel, all mission specialists. 

Short biographical sketches of the crew follow 

with detailed background available at: 

http://www.jsc.nasa.gov/Bios/
MAY 2009 CREW 37

STS-125 CREW BIOGRAPHIES 

Scott Altman 

Retired Navy Capt. Scott Altman will lead the 

crew of STS-125/SM4 on the fifth and final 

shuttle mission planned to service the Hubble 

Space Telescope. Altman served as the pilot on 

STS-90 in 1998 and STS-106 in 2000. He was the 

commander of STS-109 in 2002, the fourth 

Hubble servicing mission. He has overall 

responsibility for the safety and execution of 

this mission, orbiter systems operations and 

flight operations, including landing. He will fly 

Atlantis through its rendezvous and capture of 

the space telescope and will fly the shuttle 

during Hubble’s release. Altman will be 

involved in the robotic inspection of Atlantis’ 

heat shield. 
38 CREW MAY 2009

Gregory C. Johnson 

Astronaut Gregory C. Johnson, a captain in the 

Navy reserve component, has more than 9,000 

flight hours in 50 aircraft, including over 500 

carrier landings. He will make his first journey 

into space as the pilot of Atlantis’ STS-125/SM4 

mission. Selected by NASA in 1998, he has 

worked technical aspects of shuttle launches, 

landings and integration for the astronaut office 

and Space Shuttle Program. He will be 

responsible for orbiter systems operations and 

will assist Altman in the rendezvous with 

Hubble. Other responsibilities include 

orchestrating the photographic and video 

documentation of the mission. 
MAY 2009 CREW 39

Michael Good 

Air Force Col. Michael Good will be making his 

first spaceflight as mission specialist 1. Selected 

as an astronaut in 2000, Good has worked in the 

astronaut office advanced vehicles and space 

shuttle branches. To service Hubble, he will 

conduct the second and fourth spacewalks with 

Mike Massimino and serve as a coordinator of 

the other three. Good also will be involved in 

the robotic inspection of Atlantis’ heat shield 

and assist with range and rate information 

during rendezvous and deployment of Hubble. 

He will be seated on the flight deck for launch 

and on the middeck for landing. 
40 CREW MAY 2009

Megan McArthur 

Astronaut Megan McArthur will be making her 

first spaceflight as mission specialist 2. She has 

a doctorate in oceanography from the Scripps 

Institution of Oceanography, University of 

California-San Diego. Selected in 2000, 

McArthur has worked in the astronaut office 

space shuttle branch, served as a crew support 

astronaut for Expedition 9 and worked as a 

spacecraft communicator in Mission Control. 

She will be responsible for the robotic arm 

operations during the capture and release of 

Hubble, as well as during the spacewalks and 

Atlantis’ heat shield inspections. She also will 

serve as the flight engineer, assisting Altman 

and Johnson on the flight deck during ascent 

and landing. 
MAY 2009 CREW 41

John Grunsfeld 

Astronaut John Grunsfeld will be making his 

third trip to Hubble and his fifth spaceflight, 

serving as mission specialist 3. He has a 

doctorate in physics from the University of 

Chicago and has conducted research in X-ray 

and gamma-ray astronomy, high-energy cosmic 

ray studies and development of new detectors 

and instrumentation. He performed five 

spacewalks to service the telescope on STS-103 

in 1999 and STS-109 in 2002. He also flew on 

STS-67 in 1995 and STS-81 in 1997. Grunsfeld is 

the payload commander on STS-125/SM4, 

responsible for the telescope’s systems. He will 

lead the team of spacewalkers on the five 

excursions to service Hubble, conducting the 

first, third and fifth spacewalks with Andrew 

Feustel. They will serve as coordinators for the 

other two spacewalks. Grunsfeld will be on the 

middeck for launch and landing. 
42 CREW MAY 2009

Mike Massimino 

Astronaut Mike Massimino will be making his 

second spaceflight and trip to the Hubble Space 

Telescope, serving as mission specialist 4. He 

has a doctorate in mechanical engineering from 

Massachusetts Institute of Technology. He 

performed two spacewalks to service the 

telescope during the STS-109 mission in 2002. 

He is the lead of one of the two spacewalking 

teams on STS-125/SM4, conducting the second 

and fourth spacewalks with Good. They will 

serve as coordinators of the other three 

spacewalks. Massimino also will be involved in 

the robotic inspection of Atlantis’ heat shield 

and have backup robotic arm operation 

responsibilities for Hubble’s capture and 

release. He will be seated on the middeck for 

launch and the flight deck for landing. 
MAY 2009 CREW 43

Andrew Feustel 

Astronaut Andrew Feustel will be making his 

first trip into space, serving as mission 

specialist 5. He has a doctorate in geological 

sciences from Queen’s University. Selected as 

an astronaut in 2000, he has worked in the 

astronaut office space shuttle and space station 

branches. On STS-125/SM4, Feustel will 

perform the first, third and fifth spacewalks 

with Grunsfeld. They will serve as 

coordinators for the other two spacewalks. 

Feustel also will assist with range and rate 

information during rendezvous and 

deployment of Hubble and be responsible for 

Atlantis' onboard computing network 

throughout the flight. Feustel will be on the 

middeck for launch and landing. 
44 CREW MAY 2009

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MAY 2009 PAYLOAD OVERVIEW 45

PAYLOAD OVERVIEW 

HUBBLE SERVICING MISSION 

PAYLOAD BAY HARDWARE 

There will be four support structures flying in 

Atlantis’s cargo bay that will carry the 

science instruments, flight hardware, support 

equipment and tools to be used during the 

mission. 

• Flight Support System (FSS) 

• Super Lightweight Interchangeable 

Carrier (SLIC) 

• Multi-Use Lightweight Equipment (MULE) 

Carrier 

• Orbital Replacement Unit Carrier (ORUC) 

FLIGHT SUPPORT SYSTEM (FSS) 

The Flight Support System (FSS) is a reusable 

equipment system that provides the structural, 

mechanical, and electrical interfaces between a 

spacecraft and the orbiter for launch, retrieval, 

and in-orbit servicing missions. It also served 

as the maintenance platform holding Hubble in 

place while providing a means for rotation 

about two axes for correct positioning during 

deployment and in-orbit servicing. 

The FSS configuration for spacecraft 

deployment or retrieval consists of three 

structural cradles, mechanisms for spacecraft 

retention and positioning, and avionics. The 

cradles provide the structural support for the 

payload and storage locations for tools and 

electronics. The mechanisms for retention and 

positioning allow the spacecraft to be docked to 

the FSS, serviced, and released. The FSS 

provides the electrical interface between the 

orbiter and the Hubble, and between the orbiter 

and the servicing mission payload elements. 

The avionics provide all necessary power, 

command, control, and data monitoring 

interfaces to support operational modes of the 

spacecraft. The avionics also provide for 

remote control of all FSS mechanisms from the 

orbiter aft flight deck. The configuration for 

in-orbit servicing typically consists of one 

cradle with Berthing and Positioning System, 

mechanisms, and avionics. 

The FSS has a specific configuration for 

servicing the Hubble Space Telescope. The 

Hubble servicing configuration consists of a 

single cradle, avionics, mechanisms, and the 

Berthing and Positioning System (BAPS). Once 

Hubble is berthed to the FSS, the BAPS is used 

to orient the Hubble for servicing and to react 

to loads induced by reboosting Hubble to a 

higher orbit. The avionics and mechanisms 

used for Hubble servicing are a subset of the 

full complement available, with additional 

power capability. 

SOFT CAPTURE AND RENDEZVOUS 

SYSTEM (SCRS) 

Preparing for the Future 

When the Hubble Space Telescope reaches the 

end of its life, NASA will need to deorbit 

it safely using a next-generation space 

transportation vehicle. 

Originally planned for Earth return on the 

shuttle, Hubble’s scientific life will now extend 

beyond the planned retirement date of the 

shuttle in 2010. As part of Servicing Mission 4, 

engineers have developed the Soft Capture and. 
46 PAYLOAD OVERVIEW MAY 2009

The Soft Capture Mechanism is readied for STS-125 at Goddard Space Flight Center. 

Rendezvous System, or SCRS, which will 

enable the future rendezvous, capture, and safe 

disposal of Hubble by either a crewed or 

robotic mission. The SCRS greatly increases the 

current shuttle capture envelop interfaces on 

Hubble, therefore significantly reducing the 

rendezvous and capture design complexities 

associated with the disposal mission. 

The SCRS is comprised of the Soft Capture 

Mechanism (SCM) system and the Relative 

Navigation System (RNS). 

The Soft Capture Mechanism 

The Soft Capture Mechanism (SCM) will launch 

on a turn-table like piece of equipment called 

the Flight Support System (FSS) within the 

cargo bay of the shuttle. The FSS serves as the 

berthing platform for Hubble and provides all 

electrical and mechanical interfaces between the 

shuttle and the telescope while Hubble is 

docked. 

The SCM uses a Low Impact Docking System 

(LIDS) interface and associated relative 

navigation targets for future rendezvous, 

capture, and docking operations. The system’s 

LIDS interface is designed to be compatible 

with the rendezvous and docking systems to 

be used on the next-generation space 

transportation vehicle 
MAY 2009 PAYLOAD OVERVIEW 47

During the mission, astronauts will attach the 

SCM to Hubble. About 72 inches in diameter 

and 2 feet high, the SCM will sit on the bottom 

of Hubble, inside the FSS berthing and 

positioning ring, without affecting the normal 

FSS-to-Hubble interfaces. It will be attached 

onto the telescope by three sets of jaws that 

clamp onto the existing berthing pins on 

Hubble’s aft bulkhead. 

The astronauts will drive a gearbox, and the 

jaws will release the SCM from the FSS and 

clamp onto Hubble’s berthing pins. It can be 

transferred to Hubble at any time during the 

mission. 

The Relative Navigation System 

The Relative Navigation System (RNS) is an 

imaging system consisting of optical and 

navigation sensors and supporting avionics. It 

will collect data on Hubble during capture and 

deployment. 

The RNS system will acquire valuable 

information about Hubble by way of images 

and video of the telescope’s aft bulkhead as the 

shuttle releases it back into space. 

This information will enable NASA to pursue 

numerous options for the safe de-orbit of 

Hubble. 

The RNS system will be carried on the MultiUse Lightweight Equipment (MULE) carrier 

aboard the shuttle. 

SUPER LIGHTWEIGHT 

INTERCHANGEABLE CARRIER (SLIC) 

A New Kind of Equipment Carrier 

Each time astronauts upgrade the Hubble Space 

Telescope, the new equipment rides to orbit 

on specialized pallets called carriers. The 

composite Super Lightweight Interchangeable 

Carrier (SLIC) is a new breed of equipment 

carrier that will allow the space shuttle to 

transport a full complement of scientific 

instruments and other components to Hubble. 

Carriers transport Hubble’s new cargo in the 

space shuttle’s payload bay, protecting the 

cargo from the stress of launch and the trip to 

orbit. They also serve as temporary parking 

places for hardware during spacewalks. 

Once the mission is complete and the new 

hardware has been installed on Hubble, carriers 

provide storage space and protection for the old 

equipment’s journey back to Earth. 

These large carriers, which span the width of 

the shuttle’s payload bay, add thousands of 

pounds to the weight of the shuttle. Since the 

fully loaded shuttle cannot exceed a specified 

maximum weight limit, every pound trimmed 

from a carrier is one more pound that can be 

used for additional payload, e.g., science 

instruments or fuel for maneuvering or reboost. 

Trimming Pounds, Gaining Strength 

Anticipating that Servicing Mission 4 will need 

to carry a full load of instruments and 

equipment to orbit, in addition to equipment 

that will be needed to inspect the shuttle’s 

thermal protection system (TPS), the Hubble 

Space Telescope team built SLIC using state-ofthe-art, lightweight composite materials and a 

more structurally efficient design. Engineers 

dramatically increased performance and loadcarrying capability while significantly reducing 

weight. Compared to aluminum and titanium, 

which are metals typically used in spacecraft 

and launch vehicle design, the composites 

used to build SLIC have greater strength-tomass ratios. SLIC features other attractive 

performance characteristics such as fatigue 
48 PAYLOAD OVERVIEW MAY 2009

resistance, which means it is less susceptible to 

wear and tear. 

Made of carbon fiber with a cyanate ester resin 

and a titanium metal matrix composite, SLIC is 

the first all-composite carrier to fly on the 

shuttle. This flat, reusable pallet looks very 

different from the carriers flown on previous 

Hubble servicing missions because of its 

efficient design. This design plus SLIC’s 

composite construction makes it much lighter 

and stronger than traditional aluminum 

carriers. About half the weight of its 

predecessors, SLIC shows a dramatic increase 

in performance over other Hubble equipment 

carriers, with nearly double the carrying 

capability. 

Weighing in at just 1,750 pounds, SLIC will 

carry Hubble’s newest camera, the 980-pound 

Wide Field Camera 3, which will ride to orbit in 

a 650-pound protective enclosure. SLIC also 

will carry two new batteries, each weighing 

460 pounds. 

Benchmark for Technology 

As the pathfinder for the use of composites in 

human spaceflight, SLIC has established the 

benchmark for technology required for future 

space missions, including analysis, testing and 

verification. 

Following in the footsteps of SLIC’s 

development, future human and robotic 

exploration missions will benefit from the use 

of composite materials. Engineers for programs 

such as the Orion Crew Exploration Vehicle are 

currently in discussions with Goddard 

engineers to learn how they succeeded with 

SLIC so they, too, can construct stronger, more 

efficient composites in decades to come. 

SLIC Capabilities and Characteristics 

• Structure weight: 1,750 pounds 

• Load capability: 5,500 pounds 

• Hubble Servicing Mission payload weight: 

3,700 pounds 

• Performance (Load Capability/Weight): 3.14 

• Size: 180" x 104" 

• Structurally interchangeable: Wings can be 

added to increase deck size 

• Honeycomb surface can accommodate 

various payloads using post-bonded inserts 

• Compatible with all Hubble carrier avionics 

ORBITAL REPLACEMENT UNIT CARRIER 

The ORUC is centered in Atlantis’ payload bay. 

It provides safe transport of ORUs to and from 

orbit. 

• The Cosmic Origins Spectrograph (COS) is 

stored in the Axial Scientific Instrument 

Protective Enclosure (ASIPE). 

• The Fine Guidance Sensor (FGS) is stored in 

the Radial Scientific Instrument Protective 

Enclosure (FSIPE). 

• Three Rate Sensor Units (RSU) are stored on 

the starboard side Small ORU Protective 

Enclosure (SOPE). 

• The ORUC houses other hardware, 

including the Fine Guidance Sensor (FGS) 

and WF/PC Handhold stored on the port 

side Forward Fixture, an Aft Fixture, 

Scientific Instrument Safety Bar, MLI Repair 

Tool, two STS PFRs and an Extender, two 

Translation Aids (TA) and STIS MEB 
MAY 2009 PAYLOAD OVERVIEW 49

replacement cover. It also carries two 

Auxiliary Transport Modules (ATM), a 

Large ORU Protective Enclosure (LOPE), a 

New ORU Protective Enclosure (NOPE) 

and Fastener Capture Plate (FCP) enclosure 

to house miscellaneous CATs for the STIS 

and ACS repair work. 

The protective enclosure, its heaters and 

thermal insulation control the temperature of 

the new ORUs, providing an environment with 

normal operating temperatures. Struts between 

the ASIPE enclosure and the pallet protect 

science instruments from loads generated at 

liftoff and during Earth return. 

Also on the ORUC will be an IMAX 3D Cargo 

Bay Camera. 

IMAX Hubble 3D Movie 

Hubble 3D (working title), from the Space Station 

3D filmmaking team, tells the story of the most 

important, scientific instrument since Galileo, 

and the greatest success in space since the 

Moon Landing: the Hubble Space Telescope. 

Hubble has revealed our universe to us as 

never before. With Hubble’s amazing treasure 

trove of imagery brought to life in IMAX 3D, 

audiences of all ages will be able to explore the 

grandeur of galaxies, nebulae, birth and death 

of stars, and the curiosities and mysteries of our 

celestial surroundings as never before. With its 

dramatic story of endeavor, near catastrophic 

failure, and ultimate rescue, Hubble 3D will 

provide a unique legacy for generations to 

come, all in amazing IMAX 3D. 

Hubble 3D marks the fifth time the IMAX 3D 

Cargo Bay Camera has flown aboard the 

space shuttle. The IMAX team has trained the 

mission’s commander and pilot on the 

operation of the camera, which is mounted in 

the optimum position in the shuttle’s cargo bay 

to capture stunning IMAX 3D images of 

the historic final servicing mission. The 

commander and pilot will double as 

filmmakers as two teams of spacewalking 

astronauts, working in tandem with the 

shuttle’s robot arm, perform the most complex 

and challenging work ever undertaken in space 

as they replace and refurbish many of the 

telescope’s delicate precision instruments. 

The Hubble 3D movie will be in IMAX and 

IMAX 3D theaters worldwide beginning 

spring 2010. 

MULTI-USE LIGHTWEIGHT EQUIPMENT 

CARRIER 

The MULE is located in Atlantis’ aft payload 

bay. It has provisions for safe transport of 

ORUs to orbit: 

• The Contingency ORU Protective Enclosure 

(COPE) contains the spare ORUs and tools. 

• The MULE Integrated NOBL Container 

(MINC) contains the new NOBL protective 

coverings to be installed on the Telescope 

Support Systems Module Equipment 

Section (SSM-ES) bay doors. 

• The MULE also carries other hardware 

including eight Aft Shroud Latch Repair 

Kits and Low Gain Antenna Protective 

Covers (LGAPC). 

• The replacement SI C&DH will ride to orbit 

on the MULE. The unit is a collection of 

14 components, arranged in six stacks that 

are mounted on a tray to create a single 

Orbital Replacement Unit (ORU). 
50 PAYLOAD OVERVIEW MAY 2009

THE THREE “R’S” OF STS-125 

All of the payloads, tools and work on the 

telescope that will take place during STS-125 

can be thought of as falling into a new version 

of the Three Rs rule. But instead of Reading, 

(w)Riting and (a)Rithmithic., the STS-125 

version involves: 

• Refurbish – Hardware and activities that 

will extend Hubble’s operating life by 

installing new Battery Module Units 

(BMUs), new Rate Sensor Units (RSUs), 

New Outer Blanket Layer (NOBL) material 

and an upgraded Fine Guidance 

Sensor (FGS). 

• Restore – The astronauts will make repairs 

to two science instruments that have 

stopped working – Advanced Camera for 

Surveys (ACS) and the Space Telescope 

Imaging Spectrograph (STIS). 

• Renew – Two brand new science 

instruments – Wide Field Camera-3 

(WFC-3) and the Cosmic Origins 

Spectrograph (COS) will be installed. 

REFURBISH ACTIVITIES 

RATE SENSOR UNITS (RSUS) 

During Servicing Mission 4, astronauts will 

replace all six of Hubble’s gyroscopes, which 

are needed to point the spacecraft. Gyroscopes, 

or gyros, measure rates of motion when Hubble 

is changing its pointing from one target (a star 

or planet, for example) to another, and they 

help control the telescope’s pointing while 

scientists are observing targets. 

Each gyro is packaged in a Rate Sensor 

assembly. The assemblies are packed in pairs 

inside boxes called Rate Sensor Units (RSUs). It 

is the RSU that astronauts change when they 

replace gyros, so gyros are always replaced two 

at a time. 

Previously, Hubble needed three of the 

six gyros to conduct science, and the other 

three functioned as spares. However, after 

substantial changes to Hubble’s pointing 

control algorithms, only two gyros are now 

needed. 

How Gyros Work 

Gyros are used to maintain orientation and 

provide stability in boats, aircraft and 

spacecraft. They work by a scientific principle 

called the gyroscopic effect. You can 

demonstrate this effect by holding a bicycle 

wheel by its axle and asking someone to spin 

the wheel. If you try to move the axle of the 

spinning wheel, you will feel a force opposing 

your attempt to move it. This force is similar to 

the one produced in the gyros when Hubble 

moves. 

The gyroscopic function is achieved by a wheel 

inside each gyro that spins at a constant rate of 

19,200 rpm on gas bearings. This wheel is 

mounted in a sealed cylinder, which floats in a 

thick fluid. Electricity is carried to the motor by 

thin wires (approximately the size of a human 

hair) that are immersed in the fluid. Electronics 

within the gyro detect very small movements of 

the axis of the wheel and communicate this 

information to Hubble’s central computer. 
MAY 2009 PAYLOAD OVERVIEW 51

The STS-125 crew receives an overview on gyros and their role on the 

Hubble Space Telescope. 

The Best Gyros in the World 

Several different types of gyros are available, 

such as the mechanical gyro that uses ball 

bearings instead of gas. Other gyros use light 

or the frequency of a resonating hemisphere to 

detect movement. While all these methods can 

provide information on the movement of the 

telescope, only gas-bearing gyros offer 

extremely low noise with very high stability 

and resolution. Gas-bearing gyros are the most 

accurate in the world, and Hubble uses the best 

gas-bearing gyros available. 

Hubble’s gyros are extraordinarily stable and 

can detect extremely small movements of the 

telescope. When used with other fine-pointing 

devices, they keep the telescope pointing very 

precisely for long periods of time, enabling 

Hubble to produce spectacular images of 

galaxies, planets and stars and to probe to the 

farthest reaches of the universe. 

The Status of Hubble’s Gyros 

Gyros have limited lifetimes and need to be 

replaced periodically. Currently, three of the 

six gyros are working. 

In 2005 Hubble began operating in two-gyro 

mode. With two useable spare gyros, Hubble’s 

operating life can be extended and thus 

Hubble’s science observations can continue 

uninterrupted until the servicing mission. 

History of Gyro Replacement 

Four new gyros were installed on Hubble in 

1993 and all six gyros were replaced in 1999. 

During the servicing mission in 2009, 
52 PAYLOAD OVERVIEW MAY 2009

astronauts will replace all six gyros, which are 

nearing the end of their projected useful life. 

BATTERY MODULE UNITS (BMUS) 

Powering Hubble 

When astronauts return to the Hubble Space 

Telescope during the servicing mission, they 

will replace all six of the telescope’s 125-pound 

nickel hydrogen batteries. These batteries 

provide all the electrical power to support 

Hubble operations during the night portion of 

its orbit. 

The telescope’s orbit is approximately 

96 minutes long, about 60 minutes of which are 

in sunlight and 36 minutes are in the Earth’s 

shadow (night). During Hubble’s sunlight or 

daytime period, the solar arrays provide power 

to the onboard electrical equipment. They also 

charge the spacecraft’s batteries, so that the 

batteries can power the spacecraft during 

Hubble’s night. 

All six batteries are normally used at the same 

time. Like the ones they replace, the six new 

batteries reside in two modules, each 

containing three batteries. Each module weighs 

460 pounds and measures 36 inches long, 

32 inches wide, and 11 inches high. Astronauts 

will remove the old battery modules from 

equipment bays No. 2 and No. 3, and will 

install the new modules in the same locations. 

Each of the six batteries begins its life on the 

ground with approximately 88 amp-hrs of 

capacity. Each battery contains 22 individual 

cells wired together in series. Due to 

limitations of Hubble’s thermal control system, 

the batteries can only be charged to 75 amp-hrs 

when installed on Hubble. The six new 

batteries will begin their life in orbit by 

delivering a total of over 450 amp-hrs of 

capacity to Hubble. 

Durable and Reliable 

Now 19 years into its mission, Hubble’s nickel 

hydrogen batteries have lasted more than 

13 years longer than their design orbital life – 

longer than those in any other spacecraft 

located in low Earth orbit. This was possible 

partly because the batteries were built to very 

exacting standards using an extremely robust 

design. Nickel hydrogen battery chemistry is 

very stable and is known to exceed in-orbit 

performance requirements for long-duration 

missions. 

Another reason for the batteries’ longevity is 

that they are very carefully managed on a daily 

basis by Electrical Power System engineers at 

Goddard Space Flight Center, which has 

resulted in improved long-term in-orbit 

performance. This is done by closely 

monitoring the amount of current that flows 

into the batteries and their temperature during 

each charging cycle. Due to aging and cycling, 

the batteries are showing a slow loss in 

capacity, a normal and expected trend. If not 

replaced, they will eventually be unable to 

support Hubble’s science mission. 

The replacement batteries are superior to the 

old ones in several ways. The new batteries are 

made using a “wet slurry” process, in which 

powdered metallic materials mixed in a wet 

binder agent are poured into a mold and heated 

until the liquid boils off, leaving a porous solid. 

This process produces batteries which are 

physically stronger and better performing than 

the “dry sinter” batteries they are replacing. 

Metallic materials are mixed dry and pressed 

into a mold under high pressure in the “dry 

sinter” manufacturing process. Each new 
MAY 2009 PAYLOAD OVERVIEW 53

battery also has the added safety feature of 

battery isolation switch that electrically 

dead-faces each connector. “Dead-face” means 

no electrical power is present at the connectors 

while the switch is in the “off” position. This 

creates a safer environment for astronauts 

installing the battery modules. 

NASA uses nickel hydrogen batteries because 

they are highly reliable and are able to handle 

deep discharging better than other types of 

batteries. Nickel hydrogen batteries also can 

store more energy than other types of similar 

size. They perform very well over long 

missions in low Earth orbit, and have been used 

on many NASA missions in the past decade. 

SCIENCE INSTRUMENT COMMAND & 

DATA HANDLING (SI C&DH) MODULE 

When astronauts return to the Hubble during 

Servicing Mission 4, they will replace the 

Science Instrument Command and Data 

Handling, or SI C&DH, module. The SI C&DH 

provides all of the electronics to command 

Hubble’s science instruments from the ground 

and to flow science and engineering data back 

to the ground. 

The SI C&DH works with Hubble’s data 

management Unit (DMU) to process, format, 

and temporarily store information on Hubble’s 

digital recorders or transmit science and 

engineering data to the ground. The SI C&DH 

is a collection of 14 components, arranged in six 

stacks that are mounted on a tray to create a 

single Orbital Replacement Unit (ORU). 

The “brains” of the SI C&DH is the NASA 

Standard Spacecraft Computer, (NSSC-1). It 

contains a Central Processing Module (CPM) 

that runs the NSSC-1 software, four memory 

modules that store software and instrument 

commands and a Standard Interface (STINT) 

unit, which serves as the communications 

interface between the NSSC-1 and the Control 

Unit/Science Data Formatter, or CU/SDF. The 

flight software in the NSSC-1 computer 

monitors and controls the science instruments 

and the NICMOS Cooling System. The “heart” 

of the SI C&DH is the CU/SDF. It distributes all 

commands and data to designated destinations 

on the Hubble spacecraft such as the DMU, the 

NSSC-1, and the science instruments. It also 

translates the engineering and science data it 

receives into standard formats. 

The remaining components of the SI C&DH 

perform basic housekeeping functions such as 

distributing and switching power and 

transmitting system signals. The SI C&DH 

components are configured as redundant sets, 

known as the “A” side and the “B” side. This 

redundancy allows for recovery from any one 

failure. 

FINE GUIDANCE SENSOR 

The Fine Guidance Sensor (FGS) that will be 

taken to orbit on the servicing mission is an 

optical sensor that will be used on the Hubble 

Space Telescope to provide pointing 

information for the spacecraft and also as a 

scientific instrument for astrometric science. 

A FGS consists of a large structure housing a 

collection of mirrors, lenses, servos, prisms, 

beam splitters and photomultiplier tubes. 

There are three fine guidance sensors on 

Hubble located at 90-degree intervals around 

the circumference of the telescope. Along with 

the gyroscopes, the FGSs are a key component 

of Hubble’s highly complex but extraordinarily 

effective “pointing control system.” In this role 

the FGSs’ job is to acquire and “lock” onto 
54 PAYLOAD OVERVIEW MAY 2009

pre-chosen guide stars, feeding the position 

signals to the main Hubble computer where 

small but inevitable drifts in the gyro signals 

can be corrected. The end result is a rocksteady telescope which can take full advantage 

of its optics and instrumentation to perform 

world-class science on the full gamut of 

astronomical targets. Typically, two FGSs are 

used, each one locked onto one guide star. 

Find Guidance Sensor (FGS) 

There is more to the FGS story than “just” 

pointing control. The third FGS can be used as 

a scientific instrument for astrometry – the 

precise measurement of stellar positions and 

motions. The FGS chosen to be the “astrometer 

FGS” is the one which has the best 

performance. Currently, that role is filled by 

FGS1, and it will not be changed out during the 

servicing mission. The new FGS will take the 

place of FGS2 and the likelihood is that the new 

FGS will become the new astrometer. 

Pointing Control – How Good? 

The pointing requirement for Hubble is that the 

stability of the telescope – the so-called 

“jitter”—be no worse than 0.007 arcsecond 

(arcsec for short) for 95 percent of the time. 

What is an “arcsec”? One arcsecond is the 

angle created by the diameter of a dime 

(3/4 inch) at a distance of approximately 

2.5 miles (4 km). For example, the diameter of 

the moon as seen from Earth is roughly 

1800 arcseconds. After the FGSs lock onto 

guide stars, they can measure any apparent 

motion to an accuracy of 0.0028 arcsec. 

Combination of the FGS and gyro signals in the 

pointing control software gives Hubble the 

ability to remain pointed at targets with no 

more than 0.007 arcsec of deviation over long 

periods of time. This level of stability and 

precision is comparable to being able to hold a 

laser beam focused on a dime that is 200 miles 

away (the distance from Washington D.C. to 

New York City). 

Astrometry Science 

Astrometry is the science that deals with the 

determination of precise positions and motions 

of stars. The FGSs can provide star positions 

that are about 10 times more precise than those 

observed from a ground-based telescope. 
MAY 2009 PAYLOAD OVERVIEW 55

When used for astrometric science the FGSs 

will let Hubble: 

• Search for wobbles in the motion of nearby 

stars that could be indicative of planetary 

companions. 

• Determine if certain stars really are double 

stars. 

• Measure the angular diameter of stars, 

galaxies and other celestial objects. 

• Refine the positions, distances and energy 

output of stars. 

• Help determine the true distance scale for 

the universe. 

Servicing 

The FGS that was returned on SM3A has been 

refurbished and upgraded for re-use on 

Hubble’s Servicing Mission 4. This refurbished 

unit has an enhanced in-orbit alignment 

capability over the original FGS design. 

FGS PHYSICAL CHARACTERISTICS 

Size 5.5 x 4 x 2 feet

Weight 478 pounds

Power 19 Watts

NEW OUTER BLANKET LAYERS (NOBLS) 

During the Hubble Space Telescope Second 

Servicing Mission in 1997 and subsequent 

missions, astronauts observed damage to some 

of the telescope’s thermal insulation. Years of 

exposure to the harsh environment of space had 

taken a toll on Hubble’s protective multi-layer 

insulation, and some areas were torn or broken. 

This multi-layer insulation protects the 

observatory from the severe and rapid 

temperature changes it experiences as it moves 

through its 97-minute orbit from very hot sun 

to very cold night. 

Protecting and Maintaining Normal 

Operating Temperatures 

The New Outer Blanket Layer (NOBL) covers 

protect Hubble’s external blankets. They 

prevent further degradation of the insulation 

and maintain normal operating temperatures of 

Hubble’s electronic equipment. Each NOBL 

has been tested to ensure that it can withstand 

exposure to: charged particles, X-rays, 

ultraviolet radiation, and thermal cycling for at 

least 10 years. 

The covers are made of specially coated 

stainless steel foil which is trimmed to fit each 

particular equipment bay door that is covered. 

Each cover is supported by a steel pictureframe structure. Expanding plugs, like 

common kitchen bottle stoppers, fit into door 

vent holes to allow quick installation by the 

spacewalking astronauts. 

During Servicing Mission 3A in 1999, 

astronauts installed three NOBLs on damaged 

areas. During Servicing Mission 3B in 

March 2002, a fourth NOBL was installed. Up 

to three additional NOBL panels will be 

installed during Servicing Mission 4. 

RESTORE ACTIVITIES 

REPAIR OF ADVANCED CAMERA FOR 

SURVEYS 

The Advanced Camera for Surveys (ACS) was 

installed on the Hubble Space Telescope during 

Servicing Mission 3B in 2002. An electronics 

failure in January 2007 rendered inoperable the 

two most-used science channels, and ACS 

currently runs on one remaining channel. A 

repair attempt by spacewalking astronauts 
56 PAYLOAD OVERVIEW MAY 2009

during Servicing Mission 4 will specifically 

target restoration of the Wide Field 

Channel (WFC), the workhorse responsible for 

70 percent of the pre-2007 ACS science. The 

goal, however, is to restore both of the 

inoperable channels while preserving the third, 

bringing ACS back to full capability. 

Instrument and Repair Overview 

ACS was primarily designed to survey large 

areas of the sky at visible and red wavelengths 

with 10 times greater efficiency than the earlier 

premier Hubble camera, the Wide Field 

Planetary Camera 2 (WFPC2). For five years 

ACS brilliantly lived up to that promise. Many 

of the most extraordinary images from Hubble 

were taken with the ACS/ WFC, most famously 

perhaps the Hubble Ultra Deep Field, still the 

deepest, most detailed look into the early 

universe after galaxies had begun to form. The 

High Resolution Channel (HRC) provided 

higher angular resolution over a smaller 

field-of-view, and it included an option for 

corona-graphic imaging of faint objects around 

bright stars. The Solar-Blind Channel (SBC) – 

the one channel still working—was designed to 

provide small field-of-view imaging in the far 

ultraviolet region of the spectrum. Following 

its installation on Hubble, the ACS became the 

observatory’s most heavily used instrument. 

To increase scientific longevity, Hubble 

instruments are designed to be electrically 

redundant. The January 2007 failure was 

actually on electronics “Side 2,” an earlier 

power supply failure in 2006 having made 

Side 1 unable to operate WFC and HRC. With 

the high currents it generated, the Side 2 short 

circuit was very energetic, but it was not 

precisely localized to a particular component 

part. The failure took down operations on all 

three science channels, and the SBC is currently 

running on the portions of Side 1 that were 

unaffected by the 2006 event. Because of the 

certainty of greater damage to Side 2 and the 

more precise knowledge of what happened on 

Side 1, the Hubble Program settled on Side 1 as 

offering the greater chance for successful repair. 

To restore WFC and HRC, power not now 

available must somehow be provided to their 

control electronics. Because neither the 

partially failed Side 1 power supply nor the 

cabling which connects it to the control 

electronics is accessible to the astronauts, direct 

repair is not possible and a two-pronged 

alternative approach must be taken. The 

electronics boards that control WFC are 

accessible and will be replaced with modified 

boards. Second, a completely new power 

supply will be mounted to a handrail outside of 

ACS and mated to the new electronics with 

external cabling. 

HRC also has accessible electronics boards, but 

there is not enough EVA time available on the 

mission to allow replacement of the boards for 

both the WFC and HRC channels. However, 

inside ACS is wiring connecting the WFC and 

HRC electronics boxes which is believed to be 

intact, and by driving the new WFC electronics 

boards with the external power supply, it is 

expected, but not guaranteed, that the HRC will 

be “back-powered” and become operable. 

Astronauts will access the WFC electronics by 

removing a small panel outside the instrument. 

They must remove and replace four boards, for 

which special tools have been developed. To 

reduce repair time, a cartridge will hold the 

replacement boards and be mated into the 

electronics box with a single action. The new 

boards in their cartridge must be smaller than 

the originals. The new design incorporates a 

specialized integrated circuit called an 
MAY 2009 PAYLOAD OVERVIEW 57

Application-Specific Integrated Circuit, or 

ASIC, that enables an entire circuit board’s 

worth of electronics to be condensed into a very 

small package. A great strength of this 

approach is that the ASIC can be completely 

re-programmed by commands from controllers 

on the ground, and the WFC can be fine-tuned 

for best performance. The ASIC design is the 

same as the one already developed and tested 

for the James Webb Space Telescope (to be 

launched in 2013), although the electronics 

packaging is different because of the dissimilar 

environments for the two missions. 

The Instrument 

WFC and HRC have Charge Coupled Devices 

(CCDs) for detectors. WFC has a 4k x 4k pixel 

format created by two adjacent 2k x 4k devices. 

The CCDs were optimized for sensitivity in 

the red region of the spectrum, and spectral 

coverage extends from about 3500 Angstroms 

(A) in the blue, up beyond the visible-red to 

1.1 microns (11,000A). The field of view is 

202 x 202 arcseconds (arcsec). 

HRC’s CCD has smaller pixels in a 1k x 1k 

format. With sensitivity from 1700A to 

1.1 microns, HRC has greater spectral range 

than WFC. The field of view is 26 x 29 arcsec. 

Within HRC is a coronagraph that can place 

either of two opaque disks in front of stars so 

that nearby faint objects, e.g., brown dwarf 

companions, giant planets, or dusty disks, can 

be shielded from the stellar glare and be seen. 

In the far ultraviolet, SBC uses a Multi-Anode 

Microchannel Array (MAMA), also used by the 

Space Telescope Imaging Spectrograph (STIS) 

on Hubble. MAMAs are insensitive to visible 

light and have essentially no electronic noise. 

SBC has a 1k x 1k pixel format, a field of 

31 x 35 arcsec, and sensitivity from 1150 to 

1700A. All the detector channels employ 

selectable filters mounted on rotating filter 

wheels to transmit the desired color of light to 

the detector for any particular image. 

The restored ACS will complement the new 

WFC3, a bonus provided by the decision that 

WFC3 would not simply be a “carbon copy” of 

ACS but would have its own unique 

capabilities. The choice to optimize ACS 

performance in visible-to-red light was ideal 

for surveying red-shifted galaxies and clusters 

of galaxies at moderate-to-large distances 

across the universe. Although its sensitivity in 

visible-red wavelengths is good, WFC3’s CCD 

channel is optimized for high sensitivity, wide 

field-of-view, and high spatial resolution in the 

ultraviolet, a first for Hubble. A second 

WFC3 channel provides the high-sensitivity, 

wide-field imaging in the near-infrared (above 

1 micron) which is unavailable on ACS and 

which greatly surpasses the smaller-field Near 

Infrared Camera and Multi-Object 

Spectrograph (NICMOS). ACS and WFC3 

together enable the “best of all worlds” for 

astronomers, providing superb wide-field 

imaging over a huge range of wavelengths. 

Scientific Future of ACS 

Many scientific programs originally planned for 

ACS can be continued with WFC3. However, 

there are especially important areas for which 

the teaming of a restored ACS and WFC3 

would be especially well-suited, two examples 

being: 

• Dark Energy – The nature of Dark Energy, 

the mysterious “repulsive gravity” that 

causes accelerating expansion of the local 

universe, is one of the most compelling 

problems in contemporary physics. Dark 

Energy can be probed with Hubble through 
58 PAYLOAD OVERVIEW MAY 2009

observations of Type Ia supernovae, which 

because of their well-understood intrinsic 

brightness can be used to trace the 

expansion history of the universe over a 

sizable fraction of cosmic time. The more 

SN Ia’s that can be observed, the more 

precise becomes our understanding of 

Dark Energy’s strength and time variability 

(if any). ACS and WFC3 working in parallel 

would detect and make follow-up 

observations substantially more rapidly 

than WFC3 alone. ACS has already proven 

its remarkable capabilities in the efficient 

detection of distant supernovae. 

• Dark Matter – Approximately 24 percent of 

the universe’s matter and energy budget 

consists of a not-understood form of matter 

that neither emits nor absorbs light (hence 

is “dark”), and can only be detected by its 

gravitational influence on normal matter 

and light. By taking many images over 

large areas of sky (“tiling”), ACS has shown 

that the slight distortion of distant galaxy 

shapes produced by dark matter through 

“gravitational lensing” can be used to 

measure the amount and distribution of the 

dark matter in the universe. ACS and 

WFC3 working together would be a 

formidable team in this crucial area that, in 

spite of ACS’s tremendous work to-date, is 

still in its infancy. 

REPAIR OF SPACE TELESCOPE 

IMAGING SPECTROGRAPH 

The Space Telescope Imaging Spectrograph 

(STIS) was installed on the Hubble Space 

Telescope during Servicing Mission 2 in 1997. 

STIS stopped functioning in August 2004 due 

to a power supply failure, and is currently in 

“safe mode” pending a repair attempt during 

Servicing Mission 4. 

Instrument and Repair Overview 

STIS is a highly versatile instrument with a 

proven track record. Its main function is 

spectroscopy – the separation of light into its 

component colors (or wavelengths) to reveal 

information about the chemical content, 

temperature and motion of planets, comets, 

stars, interstellar gas and galaxies. A key 

feature of STIS is its ability to produce the 

spectrum of spatially extended objects, such as 

galaxies, covering many points across the 

image simultaneously. This is why it is called 

an “imaging spectrograph.” The instrument is 

sensitive to a wide range of wavelengths of 

light, spanning from the vacuum ultraviolet 

through the optical to the near infrared, 

Although spectrographs generally do not 

produce beautiful images like Hubble’s 

cameras, the data they provide are absolutely 

essential to understanding the physical 

properties of the material universe – they put 

the “physics” in astrophysics. At the time 

when operations suspended in August of 2004, 

STIS science constituted about 30 percent of the 

Hubble observing program. 

To repair STIS, astronauts will perform a 

spacewalk to replace a low voltage power 

supply board which contains a failed power 

converter. The repair is straightforward but 

requires diligence, and Hubble engineers have 

designed special tools for the job. If successful, 

the repair effort will restore one of two fully 

redundant electronic chains (or “sides”) of the 

instrument. Both were unusable after 

August 2004. 
MAY 2009 PAYLOAD OVERVIEW 59

STS-125 crew members visually inspect the STIS. 

The basics of the task involve installing a 

“fastener capture plate” over the top of a STIS 

electronics access panel. Astronauts will use a 

power tool to remove the 111 fasteners (screws) 

that attach the panel to STIS. The plate will 

ensure that the small fasteners are captured 

without astronauts having to grasp and stash 

them with gloved hands. 

After removing the panel (with capture plate 

and fasteners attached), the astronauts will 

remove the failed power supply card and click 

in the new one, much like replacing a circuit 

board on a computer. A new, simplified panel 

will then be installed over the open electronics 

cavity – only this time 111 fasteners will not be 

required. By throwing only two levers, the 

astronauts will latch the new panel securely 

into place. 

The Instrument 

STIS has three detectors, each with 1024 x 1024 

pixels. There’s a CCD (Charge Coupled 

Device) for detecting optical and near-infrared 

light, and two MAMA (Multi-Anode 

Microchannel Array) detectors for detecting 

near-(lower energy) and far-(higher energy) 

ultraviolet light. A limited filter set supports 

imaging, but STIS’s heart is spectroscopy, 

which is enabled by a diverse set of gratings 

ahead of the detectors in the optical chain. 

Gratings, like the more familiar prisms, create a 

spectrum by separating light into its individual 
60 PAYLOAD OVERVIEW MAY 2009

wavelength components. Close examination of 

the amount of light at each wavelength reveals 

the presence of absorption and emission lines, 

which are the “fingerprints” of the chemical 

composition and physical and dynamical states 

of stars and gas. The astronomer has a wide 

choice of gratings according to her/his needs for 

wavelength coverage and spectral resolution. 

A unique feature of STIS is that by having light 

enter a long, narrow slit before reaching the 

gratings, a separate spectrum can be recorded 

simultaneously along each of the 1024 “pixel 

rows” of the detector. By orienting the long slit, 

for example, across the nucleus of a galaxy, one 

can efficiently measure how fast the galaxy is 

rotating at different distances away from its 

center. 

In many respects STIS complements the new 

Cosmic Origins Spectrograph (COS) to be 

mounted on Hubble during the servicing 

mission. COS was designed with one primary 

purpose, to easily measure exceedingly faint 

levels of ultraviolet light emanating from very 

faint cosmic point sources, e.g., faint stars in 

our own galaxy and quasars far out across the 

universe. A repaired STIS will efficiently 

provide spatially resolved spectra of extended 

objects, spectra at visible and near-infrared 

wavelengths, very high (sharply defined) 

spectral resolution and measurements of the 

way some spectra vary with time – capabilities 

for which COS was not designed. 

Cosmic Origins Spectrograph (COS) 

Scientific Future of STIS 

Although it performed brilliantly for 7.5 years 

before suspending operations in 2004, the 

scientific potential of STIS is far from 

exhausted. Working side by side, the COS-STIS 

tandem will offer a full set of spectro-scopic 

tools for the astronomer. Each instrument 

partly backs up the other; each offers something 

the other doesn’t. Some glimpses into STIS’s 

scientific past offer a glimpse of future 

endeavors: 

• Black Holes – The light emitted by stars and 

gas orbiting around a black hole appears 

redder when moving away from us 

(redshift), and bluer when coming toward 

us (blueshift). By looking for this telltale 

Doppler shift, STIS has uncovered and 

weighed several dozen supermassive black 

holes at the cores of galaxies, but there is 

still much work to be done. To nail down 

the relationship between black hole mass 

and the properties of the host galaxies, more 

observations of both high- and low-mass 

black holes are needed. 

• Galaxies – STIS can simultaneously record 

the spectra of up to 50 spatially distinct 

locations within an extended object such as 

a galaxy. This is a crucial tool for the 
MAY 2009 PAYLOAD OVERVIEW 61

STS-125 mission specialist Mike Massimino conducts work on the STIS. 

efficient mapping of a complex 

environment. As an example, long-slit 

STIS spectra of young star clusters in the 

merging “Antennae Galaxies” revealed 

their ages, chemical compositions and 

velocities, and the slit was crucial for 

subtraction of the “sky background.” More 

STIS observations of such merging galaxies 

are important to our understanding of what 

happens to galaxies when they collide with 

each other. 

• Stars – At the time it ceased operating, STIS 

was being used in a continuing survey of 

the gas and dust blown off by the highly 

unstable, massive binary star, eta Carinae, 

which is located in our own galactic 

neighborhood, about 8000 light years from 

the sun. Astronomers expect that some day, 

perhaps a few thousand years from now, 

eta Carinae may explode as a supernova. 

STIS provides a unique opportunity to 

probe the details of the final stages of life of 

such a star before its cataclysmic death. 
62 PAYLOAD OVERVIEW MAY 2009

• Planets Around Other Stars – STIS spectra 

of the transiting star-planet system 

HD209458 resulted in transit light curves so 

precise that starlight absorption by the 

planet’s atmosphere was detected, allowing 

the identification of several planetary 

atmospheric constituents, including 

hydrogen, oxygen and sodium – a first. 

More examples of bright transiting systems 

are now known and available for study 

with a repaired STIS, and the promise of yet 

more systems being discovered is high. 

The STIS Team: NASA Goddard Space Flight 

Center led the original STIS development and is 

leading the repair effort. The principal 

investigator is Dr. Bruce E. Woodgate of NASA 

Goddard, and Ball Aerospace Systems Group is 

the prime contractor. The Space Telescope 

Science Institute in Baltimore, Md., manages 

STIS. 

RENEW ACTIVITIES 

Wide Field Camera 3 

After astronauts install the Wide Field 

Camera 3 (WFC3) during the servicing mission, 

it will continue the pioneering tradition of 

previous Hubble cameras, but with critical 

improvements to take the telescope on a new 

voyage of discovery. Together with the new 

Cosmic Origins Spectrograph (COS), WFC3 will 

lead the way to many more exciting scientific 

discoveries.

Instrument Overview 

WFC3 will study a diverse range of objects and 

phenomena, from young and extremely distant 

galaxies, to much more nearby stellar systems, 

to objects within our very own solar system. Its 

key feature is its ability to span the 

electromagnetic spectrum from the ultraviolet 

(UV, the kind of radiation that causes sunburn), 

through visible/optical light (what human eyes 

can detect), and into the near infrared (NIR, the 

kind of radiation seen with night-vision 

goggles). WFC3 extends Hubble’s capability 

not only by seeing deeper into the universe but 

also by providing wide-field imagery in all 

three regions of the spectrum – UV-Visible-NIR. 

It is this wide-field “panchromatic” coverage of 

light that makes WFC3 so unique. As an 

example, WFC3 will observe young, hot stars 

(glowing predominantly in UV) and older, 

cooler stars (glowing predominantly in the red 

and NIR) in the same galaxy. 

Should astronauts successfully repair the 

Advanced Camera for Surveys (ACS), it will 

complement the WFC3. ACS was optimized for 

wide-field imagery in the visible, and although 

it can detect UV light the field of view is small. 

ACS also was not designed to go very far into 

the NIR, a function currently served by the 

modest field-of-view NICMOS instrument. 

WFC3 will produce excellent images in the 

visible, but most importantly it will “fill in” the 

missing wide-field coverage in the UV and NIR. 

In short, WFC3 by itself, and especially WFC3 

and ACS working in tandem, will create a new 

golden age of imaging for Hubble. Moreover, 

WFC3’s ability to create crisp images of 

infrared sources makes it a steppingstone to 

NASA’s James Webb Space Telescope, Hubble’s 

successor planned for launch next decade. The 

first stars and galaxies to form in the universe 

are so old and distant that their light is now 

relegated to infrared wavelengths. WFC3 could 

bring us at last to this era. 
MAY 2009 PAYLOAD OVERVIEW 63

The Wide Field Camera 3 is inspected and readied for flight aboard STS-125. 

The Instrument 

The WFC3 is configured as a two-channel 

instrument. Its wide-wavelength coverage with 

high efficiency is made possible by this 

dual-channel design using two detector 

technologies. The incoming light beam from 

the Hubble telescope is directed into WFC3 

using a pick-off mirror, and is directed to either 

the Ultraviolet-Visible (UVIS) channel or the 

Near-Infrared (NIR) channel. The light-sensing 

detectors in both channels are solid-state 

devices. For the UVIS channel a large format 

Charge Coupled Device (CCD), similar to 

those found in digital cameras, is used. In the 

NIR detector the crystalline photosensitive 

surface is composed of mercury, cadmium and 

tellurium (HgCdTe). 

The high sensitivity to light of the 16 megapixel 

UVIS CCD, combined with a wide field of view 

(160x160 arcseconds), yields about a 35-times 

improvement in discovery power versus 

Hubble’s current most sensitive ultraviolet 

imager, the ACS High Resolution Channel. The 

NIR channel’s HgCdTe detector is a highly 

advanced and larger (one megapixel) version of 

the 65,000 pixel detectors in the current 
64 PAYLOAD OVERVIEW MAY 2009

near-infrared instrument, NICMOS. The 

combination of field-of-view, sensitivity, and 

low detector noise results in a 15-20x 

enhancement in capability for WFC3 over 

NICMOS. 

An important design innovation for the WFC3 

NIR channel results from tailoring its detector 

to reject infrared light (effectively “heat”) 

longer in wavelength than 1700 nm. In this 

way it becomes unnecessary to use a cryogen 

(e.g., liquid or solid nitrogen) to keep it cold. 

Instead the detector is chilled with an electrical 

device called a Thermo-Electric Cooler (TEC). 

This greatly simplifies the design and will give 

WFC3 a longer operational life. 

WFC3 will take the place of Wide Field 

Planetary Camera 2, which astronauts will 

bring back to Earth aboard the shuttle. 

Selected Science Goals 

Galaxy Evolution – Galaxies with new star 

formation emit most of their light at ultraviolet 

and visible wavelengths. Looking farther out 

across the universe and back in time, however, 

that light shifts toward red and near-infrared 

wavelengths. A young proto-galaxy in the 

early universe blazes strongly in ultraviolet. By 

the time that light has reached us 13 billion 

years later, its wavelength has been stretched, 

or red-shifted, by a factor of 6 to 7 or more. 

With the WFC3’s panchromatic imaging, 

astronomers will be able to follow galaxy 

evolution backward in time from our nearest 

neighboring galaxies to the earliest times when 

galaxies had just begun to form. 

Detailed Studies of Star Populations in Nearby 

Galaxies – WFC3’s panchromatic coverage, in 

particular its high UV-blue sensitivity over a 

wide field, will enable astronomers to sort out 

in detail the various populations of stars in 

nearby galaxies to learn when they were 

formed and what their chemical composition is. 

Such observations provide clues to the internal 

history of individual galaxies. They sometimes 

also reveal a history of collisions and mergers 

between galaxies. 

Dark Energy and Dark Matter – Two 

mysteries, two approaches. WFC3’s mapping 

of gravitational lenses can help determine the 

character and distribution of dark matter in 

galaxy clusters. A gravitational lens is a 

concentration of mass, such as the galaxies and 

intergalactic gas in a galaxy cluster, whose 

gravity bends and focuses light from a more 

distant object, such as a far-away galaxy, along 
MAY 2009 PAYLOAD OVERVIEW 65

our line of sight. This phenomenon was 

predicted by Einstein’s General Theory of 

Relativity and is frequently observed in 

Hubble images. WFC3 plus ACS could conduct 

systematic searches for Type Ia supernovae to 

measure the expansion history of the universe 

and get a handle on dark energy. The surveys 

will be 2-3 times more efficient than previous 

methods using ACS and NICMOS. 

WFC3 characteristics UVIS Channel NIR Channel 

Spectral range (nm) 200-1000 850-1700 

Detector type CCD HgCdTe 

Detector array size (pixels) 4096 x 4096 1024 x 1024 

Field of view (arcseconds) 160 x 160 123 x 137 

Pixel size (arcsec) 0.04 0.13 

Filter complement 62 15 

Discovery factor over previous 35x over 15-20x over 

Hubble instruments ACS/HRC NICMOS 

The Hubble Program at Goddard Space 

Flight Center jointly developed WFC3 with the 

Space Telescope Science Institute in Baltimore 

and Ball Aerospace & Technologies 

Corporation in Boulder. A community-based 

Science Oversight Committee, led by Prof. 

Robert O’Connell of the University of Virginia, 

provided scientific guidance for its 

development. 

COSMIC ORIGINS SPECTROGRAPH 

Installing the Cosmic Origins Spectrograph 

(COS) during the servicing mission will 

effectively restore spectroscopy to Hubble’s 

scientific arsenal, and at the same time provide 

the telescope with unique capabilities. 

Together with the other new Hubble 

instrument – the Wide Field Camera 3 

(WFC3) – COS will journey toward more 

ground-breaking scientific discoveries. 

Instrument Overview 

COS is designed to study the large-scale 

structure of the universe and how galaxies, 

stars and planets formed and evolved. It will 

help determine how elements needed for life 

such as carbon and iron first formed and how 

their abundances have increased over the 

lifetime of the universe. 

As a spectrograph, COS won’t capture the 

majestic visual images that Hubble is known 

for, but rather it will perform spectroscopy, the 

science of breaking up light into its individual 

components. Any object that absorbs or emits 

light can be studied with a spectrograph to 

determine its temperature, density, chemical 

composition and velocity. 

A primary science objective for COS is to 

measure the structure and composition of the 

ordinary matter that is concentrated in what 

scientists call the “cosmic web” – long, narrow 

filaments of galaxies and intergalactic gas 

separated by huge voids. The cosmic web is 
66 PAYLOAD OVERVIEW MAY 2009

shaped by the gravity of the mysterious, 

underlying cold dark matter, while ordinary 

matter serves as a luminous tracery of the 

filaments. COS will use scores of faint distant 

quasars as “cosmic flashlights,” whose beams 

of light have passed through the cosmic web. 

Absorption of this light by material in the web 

will reveal the characteristic spectral 

fingerprints of that material. This will allow 

Hubble observers to deduce its composition 

and its specific location in space. 

Observations like this, covering vast distances 

across space and back in time, will illuminate 

both the large-scale structure of the universe 

and the progressive changes in chemical 

composition of matter, as the universe has 

grown older. 

The Instrument 

COS has two channels, the Far Ultraviolet 

(FUV) channel covering wavelengths from 

115 to 177 nm, and the Near Ultraviolet (NUV) 

channel, covering 175-300 nm. Ultraviolet light, 

the type of radiation that causes sunburn, is 

more energetic than visible, optical light; and 

“near” UV refers to the part of the UV spectrum 

closer to the visible, just beyond the color violet. 

The light-sensing detectors of both channels are 

designed around thin micro-channel plates 

comprising thousands of tiny curved glass 

tubes, all aligned in the same direction. Simply 

described, incoming photons of light ultimately 

induce showers of electrons to be emitted from 

the walls of these tubes. The electron showers 

are accelerated, captured, and counted in 

electronic circuitry immediately behind the 

micro-channel plates. 

A key feature of COS – the one which makes it 

unique among Hubble spectrographs – is its 

maximized efficiency, or “throughput.” Each 

bounce of a light beam off an optical surface 

within an instrument takes some of the light 

away from the beam, reducing the throughput. 

This is a problem that is especially acute in the 

UV, and the COS FUV channel was designed 

specifically to minimize the number of light 

bounces. The incoming FUV beam makes one 

bounce off a selectable light-dispersing grating, 

and goes directly to the detector. An additional 

advantage within COS is the very low level of 

scattered light produced by its light-dispersing 

gratings. 

If astronauts are able to complete the in-orbit 

repair of the Space Telescope Imaging 

Spectrograph (STIS) aboard Hubble, it will 

serve to complement the COS. The “all 

purpose” STIS, installed in 1997 during 

Servicing Mission 2, suffered an electronics 

failure in 2004 and is currently in safe hold. By 

design, the COS does not duplicate all of STIS’s 

capabilities. Possessing more than 30 times the 

sensitivity of STIS for FUV observations of faint 

objects such as distant quasars, COS will enable 

key scientific programs which would not be 

possible using STIS. On the other hand, COS is 

best suited to observing point sources of light 

such as stars and quasars, while STIS has the 

unique ability to observe the spectrum of light 

across spatially extended objects such as 

galaxies and nebulae. Should STIS be repaired, 

the two spectrographs working in tandem will 

provide astronomers with a full set of 

spectroscopic tools for astrophysical research. 
MAY 2009 PAYLOAD OVERVIEW 67

COS CHARACTERISTIC FUV CHANNEL NUV CHANNEL 

Spectral range (nm) 115-205 170-320 

Spectral resolution 16000-24000 med. 

2000-3000 low 

16000-24000 med. 

2000-3000 low 

Detector type cross-delay line NUV MAMA 

Detector array (pixels) 32768 x 1024 1024 x 1024 

Pixel size (microns) 6 x 24 25 x 25 

Gratings 3 4

Enhancement factor over previous 

spectrograph 

Detection of objects more than 

30x fainter than with STIS 

Detection of objects more than 2x 

fainter than with STIS 

COS will be installed in the instrument bay 

currently occupied by “COSTAR,” the set of 

corrector mirrors on deployable arms that 

provided corrected light beams to the first 

generation of Hubble instruments after SM1 in 

1993. Astronauts will store the no longer 

needed COSTAR instrument aboard the shuttle 

for its return to Earth. 

Mission Science Goals 

The Origin of Large-Scale Structure – This goal 

uses the COS’ superior throughput to obtain 

absorption line spectra from the faint light of 

distant quasars as it passes through the 

nebulous intergalactic medium. The spectra 

will reveal the structure that is filtering the 

quasar light, and this will enable scientists to 

understand the hierarchal structure of the 

universe at its largest scales. Theories predict 

(and observations support) the notion of a 

cosmic web of structure. 

The COS will help determine the structure and 

composition of the ordinary baryonic matter 

that is concentrated in the cosmic web. 

Baryonic matter is made up of protons and 

neutrons, like the atoms in our body. The 

distribution of baryonic matter over cosmic 

time can best be detected, ironically, not by 

how much it glows (in stars and galaxies) but 

by how much light it blocks. 

The Formation, Evolution and Ages of Galaxies – 

This goal also will use quasar sightline 

observations. The light serves as a probe of 

galactic haloes it passes through, sampling their 

contents. By sampling galaxies near and far, 

scientists will constrain galaxy evolution 

models and measure the production of heavy 

elements over cosmic time. 

The Origin of Stellar and Planetary Systems – As 

an ultraviolet-detecting instrument, the COS 

can detect young, hot stars (hotter than our sun) 

embedded in the thick dust clouds that gave 

rise to their birth, clarifying the phenomenon of 

star formation. The COS also will be used to 

study the atmospheres of the outer planets in 

our solar system. 
68 PAYLOAD OVERVIEW MAY 2009

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MAY 2009 RENDEZVOUS & DOCKING 69

RENDEZVOUS & DOCKING 

This image depicts space shuttle Atlantis capturing the Hubble Space Telescope. 

HUBBLE SPACE TELESCOPE 

RENDEZVOUS, CAPTURE AND 

BERTHING 

The rendezvous of space shuttle Atlantis with 

the Hubble Space Telescope actually will begin 

with the precisely timed liftoff from NASA’s 

Kennedy Space Center, Fla. 

The launch will occur with the telescope 

orbiting in the same “plane” as the launch pad, 

which occurs once each day. 

After liftoff and during the first two days of the 

mission, periodic firings of the shuttle’s 

Reaction Control System thrusters and Orbital 

Maneuvering System engines will gradually 

increase and align Atlantis’ orbit with that of 

the telescope, approximately 350 statute miles 

above the Earth. 

Before the approach, the Space Telescope 

Operations Control Center at the Goddard 

Space Flight Center in Greenbelt, Md., will 

command the telescope to stow the two High 

Gain Antennas and close the aperture door to 

protect its sensitive equipment and mirror. 

About 2 1/2 hours before Hubble is captured by 

the shuttle’s robotic arm, Atlantis will drift to a 

point nearly 50,000 feet (9 1/2 statute miles) 

behind the telescope, the starting point from 
70 RENDEZVOUS & DOCKING MAY 2009

which the final approach to the observatory 

will begin. 

At that point, the crew will oversee a preciselytargeted thruster firing called the Terminal 

Initiation, or TI burn, that sets the stage for the 

final phase of the rendezvous. 

Atlantis will close the final miles to the 

telescope during the next orbit of Earth. During 

that time the shuttle’s rendezvous radar system 

will begin tracking Hubble by measuring the 

distance and rate of closure. 

During the final approach, the shuttle will 

have an opportunity to conduct four small 

mid-course corrections, if required. 

Simultaneously, Mission Specialist Megan 

McArthur will maneuver the robotic arm above 

the payload bay of Atlantis to a position poised 

to grapple a capture fixture on the telescope. 

After the fourth and final mid-course correction 

burn, the shuttle will be about a half-mile below 

the telescope. At that point, about an hour 

before the scheduled docking, Commander 

Scott Altman will move from his forward seat 

on the flight deck to the aft flight control 

station overlooking the payload bay. Looking 

out of two overhead windows, Altman, assisted 

by pilot Gregory C. Johnson and Mission 

Specialist Michael Good, will take over manual 

control of the approach. 

Good will operate a handheld laser 

range-finding device, aiming it through the 

shuttle windows at the telescope to provide 

Altman with supplementary distance and 

closing rate information. Mission Specialist 

Andrew Feustel will monitor a laptop computer 

program displaying real-time navigation 

information, which will provide Altman with 

additional cues to aid in controlling his 

approach. 

Altman will slow Atlantis’ approach and fly up 

toward the telescope, switching the Reaction 

Control System to a mode known as “low-Z” at 

a distance of about 1,500 feet. In that mode, jets 

offset to the direction of the telescope will be 

fired to continually slow the shuttle's approach, 

while avoiding any chance of contaminating 

Hubble with shuttle thruster exhaust, a 

phenomenon known as “pluming.” 

As Atlantis moves within 600 feet, its approach 

will be slowed to less than a half-mile per hour. 

As the distance decreases to about 200 feet, 

Hubble’s ground controllers will send 

commands to perform a final roll maneuver to 

position it for capture. The telescope’s solar 

arrays will remain parallel to Hubble’s optical 

axis. The shuttle will coast toward the 

observatory as it closes the final 100 feet, 

moving at a speed of only a tenth of a foot per 

second. 

Altman will fly Atlantis to within 35 feet of the 

telescope and hold position, while McArthur, 

using a view from a camera mounted at the end 

of the robotic arm to assess alignment, will 

latch on to the telescope with the robotic arm 

end effector. 

Using views from a camera centered in a 

structure where the telescope will be berthed, 

McArthur then will lower Hubble into a special 

cradle, called the Flight Support System, or FSS, 

in Atlantis’s payload bay. The telescope will be 

latched to the high-tech, lazy Susan-type device 

for the duration of the servicing work. An 

umbilical adjacent to the rotating FSS will be 

remotely connected to provide electrical power 

from Atlantis to the telescope. Then, Altman 

will position the shuttle to allow Hubble’s solar 

arrays to gather energy from the sun to fully 

charge the telescope’s batteries. 
7 

MAY 2009 RENDEZVOUS & DOCKING 71

During the five servicing spacewalks, the 

telescope’s support structure can be rotated and 

pivoted as needed to provide the best available 

access to various worksites. 

HUBBLE SPACE TELESCOPE DEPLOY 

On the day before Hubble’s deployment, 

controllers at Goddard Space Flight 

Center, Md., will send commands to unfurl the 

telescope’s high-gain antennas and conduct a 

final checkout of telemetry with the telescope’s 

control center. 

About three hours before the planned release 

time, McArthur will power up Atlantis’ robotic 

arm and latch on to the telescope’s grapple 

fixture. Altman will maneuver Atlantis to the 

correct orientation to release the observatory. 

The telescope will be switched back to its 

internal power, its aperture door will be 

commanded open to allow starlight to fall upon 

its optical instruments, and the connection to 

Atlantis’s power system will be remotely 

disconnected. Three latches securing Hubble to 

its support structure will be opened. 

After a poll of shuttle and telescope flight 

controllers, McArthur will unberth Hubble and 

maneuver it to a point high above the shuttle 

bay. Atlantis’ steering jets will be turned off to 

avoid any possible disturbance as McArthur 

commands the arm to release the telescope’s 

grapple fixture. 

About a minute later, the shuttle thrusters will 

fire in the Low-Z mode to slowly back Atlantis 

away. Another jet firing will be performed 

about a half-hour later to increase Atlantis’ 

separation rate from the telescope, as the seven 

crew members bid farewell to Hubble for the 

final time. 
72 RENDEZVOUS & DOCKING MAY 2009

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MAY 2009 SPACEWALKS 73

SPACEWALKS 

Astronaut John Grunsfeld, payload commander, peers into the crew cabin of the space shuttle 

Columbia during the first STS-109 extravehicular activity (EVA-1) on March 4, 2002. Grunsfeld’s 

helmet visor displays a mirrored image of the Earth’s hemisphere. The lower portion of the 

Hubble Space Telescope (HST) can be seen over Grunsfeld’s left shoulder. 

The five spacewalks of the STS-125 mission will 

extend the Hubble Space Telescope’s life and 

leave it with new equipment that will improve 

the data that it is able to send back to scientists 

here on Earth. More than 60 new spacewalk 

tools were developed for the work to be done 

on this mission. 

Mission Specialists John Grunsfeld, 

Andrew Feustel, Mike Massimino and 

Michael Good will spend a combined total of 

31 hours and 40 minutes outside of space 

shuttle Atlantis on flight days 4, 5, 6, 7 and 8. 

Grunsfeld, the lead spacewalker for the 

mission, will suit up for the first, third and fifth 

spacewalks in a spacesuit marked with solid 

red stripes. He is an experienced spacewalker 

with five extravehicular activities, or EVAs, 

performed in support of Hubble during 

STS-103 and STS-109. 

Massimino, another veteran spacewalker, will 

wear a spacesuit with a dashed red and white 

stripe for the mission’s second and fourth 
74 SPACEWALKS MAY 2009

spacewalks. He has two Hubble-servicing 

spacewalks under his belt, performed on 

STS-109. 

Feustel and Good will perform their first 

spacewalks. Feustel will participate in the first, 

third and fifth spacewalks and wear an all 

white spacesuit, while Good will wear a 

spacesuit with horizontal red stripes for 

spacewalks two and four. 

On each EVA day, the two spacewalkers inside 

the shuttle will act as the intravehicular officers, 

or spacewalk choreographers, for those 

working outside. And Mission Specialist 

Megan McArthur will work with the 

spacewalkers from the inside to operate the 

shuttle’s 50-foot-long robotic arm as needed. 

Unlike the preparations for International Space 

Station-based spacewalks, the spacewalkers for 

the STS-125 mission will not need to camp out 

in the shuttle’s airlock overnight to prepare for 

their time outside the shuttle. Instead, the 

entire shuttle will be kept at a pressure of 

10.2 pounds per square inch beginning on its 

second day in space, until the day after the last 

spacewalk. Doing so will decrease the amount 

of time they’ll need to spend breathing pure 

oxygen in the hours before they begin their 

spacewalk, which helps the spacewalkers avoid 

getting decompression sickness, also known as 

the bends. 

EVA-1 

Duration: 6 hours, 30 minutes

Crew: Grunsfeld and Feustel 

EVA Operations 

• Wide Field Planetary Camera 2 removal 

• Wide Field Camera 3 installation 

• Science Instrument Command and Data 

Handling Unit replacement 

• Latch Over Center Kit installation 

• Soft Capture Mechanism installation 

(get-ahead) 

Feustel will begin the first spacewalk of the 

STS-125 mission by making his way to 

Wide-field Scientific Instrument Protective 

Enclosure, in which the telescope’s new 

equipment was launched, and release some 

latches. Meanwhile Grunsfeld will set up the 

foot restraint Feustel (and later in the mission, 

Good) will use on the shuttle’s robotic arm and 

install the berthing and positioning system 

post, which will protect the telescope’s solar 

arrays from vibration while the spacewalkers 

are working. He’ll also install a fixture in the 

cargo bay that will be used to temporarily hold 

equipment after it is removed. 

Feustel will then install a handle on the foot 

restraint, before climbing on. Inside the station, 

McArthur will then maneuver him into position 

for the removal of the Wide Field Planetary 

Camera 2, or WFPC 2. They’ll replace it with a 

new wide-field camera that will allow the 

telescope to take large-scale, clear and detailed 

photos over a wide range of colors. 

Grunsfeld will take advantage of the time it 

takes Feustel to get into place by installing a 

protective cover on Hubble’s low-gain antenna. 

Once that’s done, he’ll join Feustel at the 

WFPC 2. 
MAY 2009 SPACEWALKS 75

To remove the camera, Feustel will simply 

release a blind-mate connector, a grounding 

strap and a latch, and allow the camera to slide 

out on some guide rails, while Grunsfeld 

monitors the camera’s clearance. The camera 

will be temporarily stored on the fixture 

Grunsfeld deployed, while the astronauts move 

on to the installation of the new Wide Field 

Camera 3. 

Feustel will again be doing the heavy lifting 

with the help of the shuttle’s robotic arm. He 

and Grunsfeld will install a handle on the new 

WFC 3 where it’s stowed inside the Wide-field 

Scientific Instrument Protective Enclosure, and 

then Feustel will carefully remove it while 

Grunsfeld monitors clearances. Before the 

camera can be removed, Feustel will need to 

release two vent valves, a ground strap and a 

latch. 

Feustel will carry the new camera to the former 

location of the old camera on the telescope, and 

slide it into place. He’ll secure it with a latch, a 

blind-mate interface and a ground strap that 

Grunsfeld will install on the telescope. 

Afterward, Feustel will remove the handle from 

the camera and hand it off to Grunsfeld for 

storage, and then permanently stow the 

WFPC 2 inside the Wide-field Scientific 

Instrument Protective Enclosure. 

The spacewalkers’ next major task will be the 

replacement of the Science Instrument 
76 SPACEWALKS MAY 2009

Command and Data Handling Unit. The 

computer sends commands to Hubble’s science 

instruments and formats science data for 

transmission to the ground. 

The computer will be carried to the telescope 

inside a multi-use lightweight equipment 

carrier in the shuttle’s cargo bay. Grunsfeld 

will remove the new computer from the carrier 

by releasing eight bolts, while Feustel removes 

the old computer from the telescope by 

releasing 10 bolts. Feustel will carry the old 

computer to Grunsfeld at the carrier, where the 

two will swap. Feustel will then carry the new 

computer back to the telescope and install it, 

while Grunsfeld stores the old one inside the 

carrier. 

If time permits, Grunsfeld will then install a 

soft capture mechanism, which will allow 

future vehicles to attach to the telescope. The 

mechanism will be attached to the flight 

support system – or FSS – that connects the 

shuttle to the telescope. To install it, Grunsfeld 

will only need to tighten a single bolt, which 

will both drive latches to attach it to the 

telescope and release the latches attaching it to 

the FSS. 

As a get-ahead, Feustel may also go ahead and 

open the door on the telescope’s Bay 2, where 

Massimino and Good will be working the 

following day. 

Their final scheduled task for the day will be to 

install three latch-over-center kits that will 

allow for faster opening and closing of the 

telescope doors during the third spacewalk. 

EVA-2 

Duration: 6 hours, 30 minutes 

Crew: Good and Massimino 

EVA Operations 

• Rate Sensor Units replacement 

• Bay 2 Battery replacement 

For their first spacewalk of the STS-125 mission, 

Massimino and Good will spend the bulk of 

their time replacing three rate sensor units. 

Each unit is part of a rate gyro assembly, which 

sense vehicle motion and provide rate data for 

the telescope. 

The replacement units will be stored inside a 

protective enclosure inside the shuttle’s cargo 

bay. Massimino will open the lid of the 

enclosure to allow Good, who will be riding the 

space shuttle’s robotic arm for the spacewalk, to 

retrieve the first unit and carry it to the 

telescope. Massimino will also retrieve a 

gripper tool that Good will use to maneuver the 

units into place. 

At the telescope, Good will retract two fixed 

head star tracker seals, allowing the doors on 

the telescope bay that the crew will be working 

in to open. Once open, Good will move a cross 

aft shroud harness inside the telescope to make 

room for the foot restraint Massimino will be 

using. Massimino will retrieve the foot 

restraint for Good to install, then Good will 

help Massimino into it. 
MAY 2009 SPACEWALKS 77

To remove the old rate sensor units, Massimino 

will disconnect two electrical connectors, while 

Good removes three bolts. The same 

connectors and bolts will need to be connected 

and tightened to install the replacement unit. 

The two spacewalkers will repeat this process 

two more times as they replace the remaining 

two rate sensor units. 

If time permits, Massimino and Good will do 

some get-ahead work for the third spacewalk of 

the mission by installing a power input element 

harness for the advanced camera for survey 

before they move the cross aft shroud harness 

back into place and close the doors on the 

worksite. 

After the new rate sensor units are installed, 

Massimino and Good are scheduled to perform 

the first half of the mission’s battery 

replacement work. They’ll be working in the 

telescope’s Bay 2 to replace the first of two 

batteries. Good will retrieve the old battery by 

disconnecting six electrical connectors and 

unscrewing 14 bolts, while Massimino retrieves 

the new battery from its stowage location inside 

the shuttle’s super lightweight interchangeable 

carrier. He’ll have to unscrew 12 bolts to 

remove it. 

The two astronauts will swap batteries at the 

carrier, and Good will transport the new 

battery to the telescope for installation, while 

Massimino stows the old. 
78 SPACEWALKS MAY 2009

EVA-3 

Duration: 6 hours, 30 minutes 

Crew: Grunsfeld and Feustel 

EVA Operations: 

• Corrective Optics Space Telescope Axial 

Replacement removal 

• Cosmic Origins Spectrograph installation 

• Advanced Camera for Surveys repair, 

part one 

Grunsfeld and Feustel will be back outside for 

the third spacewalk of the mission, this time 

focusing on the installation of the telescope’s 

new Cosmic Origins Spectrograph, and the first 

part of the advanced camera for survey repair 

work. 

Grunsfeld will begin by preparing a temporary 

storage fixture in the shuttle’s cargo bay, while 

Feustel opens the doors of the telescope bay he 

and Grunsfeld will be working in. Once 

everything is ready, Grunsfeld will get the 

Corrective Optics Space Telescope Axial 

Replacement – or COSTAR – ready for removal 

by unhooking four connectors, disconnecting 

one ground strap and unscrewing two latches. 

Feustel, again on the shuttle’s robotic arm, will 

actually remove the equipment and attach it to 

the temporary storage fixture Grunsfeld 

prepared. 

Both crew members will then move to the 

protective enclosure that the new Cosmic 

Origins Spectrograph was launched in and 

work together to remove it. They will need to 

disconnect a ground strap, disengage locks and 

release latches before Feustel will be able to 

remove the equipment from the carrier and 

make his way via robotic arm back to the 

telescope for its installation. 

Feustel will maneuver the equipment into place 

and engage its two latches. Grunsfeld will then 

hook up four connectors and a ground strap. 

Following that installation, the only thing left to 

do on the tasks will be to store the COSTAR in 

the protective enclosure that previously housed 

the spectrograph. 

Once that’s done, Grunsfeld and Feustel will 

begin work on the Advanced Camera for 

Surveys repair, which may be finished later in 

the mission if time permits or the Space 

Telescope Imaging Spectrograph repair on the 

fourth spacewalk is not successful. In that case, 

the rest of the Advanced Camera for Surveys 

work would be added to the fifth spacewalk, 

replacing the Fine Guidance Sensor work. 

For this spacewalk, Grunsfeld and Feustel will 

spend about two hours and 10 minutes working 

on the camera and remove two of the four 

electronics cards that need to be replaced. 

Grunsfeld’s first task will be to install four 

guide studs that will be used later to install 

tools. Feustel will assist him with that job, and 

then the two will work together to remove a 

grid. To do so, Grunsfeld will fit a grid cutter 

over the grid. Tightening the 12 bolts on the 

grid cutter will cause a blade to cut off the 

12 legs of the grid. The grid cutter will also trap 

the pieces of the grid, so that the spacewalkers 

don’t have to handle the sharp edges created by 

cutting the grid off. 

That will give them access to a cover plate, 

which is the next thing Grunsfeld and Feustel 

will need to remove. This will require 

Grunsfeld to unscrew 32 fasteners. Grunsfeld 

will first loosen all the fasteners, and then, to 

ensure that none of those fasteners are lost, he’ll 
MAY 2009 SPACEWALKS 79

install a fastener capture plate over the cover 

plate before he releases the fasteners. The 

fastener capture plate will then be removed 

along with the cover plate. 

With that, Grunsfeld will finally be able to 

access the electronics cards. Feustel will 

retrieve and hand to him a piece of equipment 

called a “wishbone” that will be used to mount 

the tool that will be used to extract the 

electronic cards from the camera. Feustel also 

will retrieve that tool for Grunsfeld, as well as 

the protective storage carrier that Grunsfeld 

will put each card into as it is removed. To 

actually remove the card, Grunsfeld will use a 

card extraction tool that has a jaw to grip the 

card, which Grunsfeld tightens by tightening 

bolts, and an elevator block that removes the 

card when Grunsfeld tightens a different bolt. 

EVA-4 

Duration: 6 hours, 30 minutes 

Crew: Massimino and Good 

EVA Operations: 

• Space Telescope Imaging Spectrograph 

repair 

• New Outer Layer Blanket 8 installation 

The bulk of Massimino and Good’s second 

spacewalk will be spent repairing the 

telescope’s Space Telescope Imaging 

Spectrograph – a task that has been compared 

to brain surgery. To access the electronics card 

the spacewalkers intend to replace, they’ll need 

to remove a cover plate. However, there are 

several obstacles to doing so. First Massimino 

will need to remove a clamp from the upper left 

corner of the cover plate. Then he’ll need to 

remove a handrail. Both of these tasks require 

special tools to catch the fasteners currently 

holding those pieces in place. The clamp 

removal tool fits over the fasteners of the clamp 

and catches them as they’re released; the 

handrail removal tool does the same over the 

fasteners of the handrail. 

The cover plate itself has 111 fasteners that 

need to be unscrewed. To ensure that none of 

those small pieces float away, another fastener 

capture plate will be installed. But to install 

the fastener capture plate, Massimino must first 

install guide studs that will be used to mount 

the plate onto the instrument. To install the 

guide studs, Massimino will have to release 

four fasteners without losing the fasteners or 

their bits. For that job, he’ll use the retainer 

installation bit caddy, which uses a retaining 

ring to go around the head of the fasteners and 

behind it to trap the washer. Then four 

fasteners can be removed with a fastener 

extraction bit, and their washers will stay in 

place to be removed by a washer extraction 

tool. 

That will leave a place for the guide studs to be 

installed, allowing for the installation of the 

fastener capture plate. Once it’s in place, 

Massimino will be able to unscrew the 

remaining 107 fasteners and washers safely, 

and – after Good has cut four wires – remove 

the cover plate. With it out of the way, 

Massimino will be able to finally access the 

electronics card that he and Good will replace. 

To actually remove the old card, Massimino 

will use a card extraction tool, just as Grunsfeld 

did during the third spacewalk. He’ll then 

store it in a transport case, detach the extraction 

tool and use the tool to unpack and install 

the new card. He’ll also install the new card’s 

simpler cover, which only requires him to 

engage two locking pins. 
80 SPACEWALKS MAY 2009

Once the new card is installed, Massimino and 

Good will wrap up their last spacewalk by 

installing one of two new protective thermal 

insulation panels – called New Outer Layer 

Blankets – delivered by space shuttle Atlantis. 

This insulation will be installed on the 

telescope’s bay 8 door, and Good will start 

the work by first removing the existing 

insulation in that area, including a temporary 

patch installed during the second Hubble 

servicing mission. This task will involve 

removing seven clips and unhooking a wire 

loop holding the patch in place, and cutting two 

ground wires to release the original insulation. 

The new insulation will be installed using four 

latches and pressure-activated adhesive that 

Good will activate by pressing a roller tool 

against its surface. 

EVA-5 

Duration: 5 hours, 45 minutes 

Crew: Grunsfeld and Feustel 

EVA Operations: 

• Bay 3 Battery replacement 

• Fine Guidance Sensor replacement 

• New Outer Layer Blanket 5 installation 

For the final spacewalk of the mission, 

Grunsfeld and Feustel will be finishing both the 

battery replacement and New Outer Layer 

Blanket installation tasks, following the same 

procedures as those of the work on the second 

and fourth spacewalks. 

Between those two jobs, however, they’ll also 

be replacing the telescope’s fine guidance 

sensor. To remove the old sensor, Grunsfeld 

and Feustel will work together to unhook nine 

connectors. Then Grunsfeld – who will be 

riding the shuttle’s robotic arm for this 

spacewalk – will release one latch and install a 

handle on the equipment that he’ll use to 

carefully lift the sensor out of the telescope. 

He’ll carry it to a protective enclosure inside the 

shuttle’s cargo bay, where Feustel will be 

waiting to assist him in storing it and removing 

the new sensor. 

Grunsfeld will carry the new sensor back to the 

worksite, slide it into place and engage its one 

latch. Then he’ll work with Feustel to hook up 

its nine connectors. 
MAY 2009 SPACEWALKS 81
82 SPACEWALKS MAY 2009

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MAY 2009 SM4 FACILITIES 83

SM4 FACILITIES 

HUBBLE SERVICING MISSION 

FACILITIES 

NASA GODDARD 

Space Telescope Operations Control Center 

(STOCC) 

The Hubble Space Telescope is kept under a 

watchful eye by a dedicated team of 

professionals at NASA Goddard Space Flight 

Center’s Space Telescope Operations Control 

Center, or STOCC. 

This group is called the Flight Operations 

Team (FOT) and is comprised of Hubble 

engineers and managers who work seven days 

a week, 365 days a year, constantly monitoring 

the telescope’s operations. 

The STOCC consists of three conjoined rooms: 

• In the Mission Operations Room the FOT 

closely monitors the telescope’s health and 

safety, as well as controlling flight 

operations. Some of the tasks they perform 

include in-depth subsystem analysis, 

simulated subsystem tests, integrating new 

databases, and validating new ground 

software and updates to flight software. 

• The Mission Support Room supports 

nominal Hubble operations through 

integrated testing for ground systems 

software updates and engineering activities 

by providing off-line mission planning 

functions, data processing and integrated 

testing. 

• Shortly before the Hubble servicing mission 

in 2009, additional engineers from the 

subsystems engineering group will be 

called upon to staff the Servicing Mission 

Operations Room. This Servicing Mission 

Operations Team (SMOT) will work in two 

12-hour shifts, supporting the preparation, 

test and simulation for the fifth and final 

shuttle mission to the famed telescope. 

Preparing Hubble for Servicing 

Just as NASA astronauts train extensively for 

each shuttle mission, so do the SMOT and FOT 

engineers. Their highly choreographed efforts 

and expertise help ensure the servicing mission 

goes as planned. 

A few hours after the shuttle Atlantis lifts off 

from Kennedy Space Center, the FOT will 

prepare the telescope for servicing by placing 

its science instruments into “safe hold.” During 

this time, engineers will track Hubble and 

downlink necessary engineering data. 

About 28 hours into the servicing mission, the 

team will command Hubble to close its 

aperture door to protect its ultra-sensitive 

optics. Then the team will send commands to 

the telescope so it obtains the required 

rendezvous attitude (for grappling by the 

shuttle arm), stows, or retracts, its high gain 

antennas, and repositions its solar arrays to 

enable the shuttle arm to grapple the telescope. 

The astronauts will then secure the telescope to 

the shuttle’s Flight Support System, which will 

allow them to reach all the instruments and 

components slated for repair or replacement. 
84 SM4 FACILITIES MAY 2009

Hubble’s internal power will be transferred to 

the shuttle during servicing. 

Testing Hubble during Servicing 

During the servicing mission, the SMOT 

engineers will perform aliveness and functional 

tests to ensure each instrument and component 

has power and operates as it should. While the 

astronauts sleep, this same team will conduct 

additional functional tests on each installed 

component to determine if the astronauts need 

to perform additional work. 

After all servicing tasks are completed, 

Hubble’s newly installed battery packs will be 

charged to full capacity. The shuttle supplied 

power feed will be disconnected and Hubble 

will operate under its own internal power. 

The FOT engineers will send commands to 

Hubble to open its aperture door and the 

telescope will be released. Additional 

commands will be sent to deploy Hubble’s high 

gain antennas and after orbital verification is 

completed, Hubble will be recommissioned for 

future science observations. 

Scheduling Science Observations 

The Space Telescope Science Institute in 

Baltimore, Md., annually solicits Hubble 

science research proposals from the worldwide 

astronomical community and competitively 

selects the most compelling science 

observations to place on Hubble’s science 

observing schedule. 

The FOT engineers upload these approved 

observing schedules to the telescope via a 

network interface to NASA’s White Sands 

Complex in New Mexico, which then transmits 

to NASA’s Tracking and Data Relay Satellite 

System for uplink to Hubble. Conversely, 

scientific data obtained by Hubble are sent back 

to Goddard by reverse path, and forwarded to 

the Space Telescope Science Institute via 

dedicated high-speed links. 

Since the Tracking and Data Relay Satellite 

System supports several orbiting spacecraft, all 

commands and returning data are carefully 

choreographed. Hubble’s command sequences 

are uplinked periodically and stored in the 

telescope’s onboard computer. Hubble then 

executes the observations automatically at 

pre-scheduled times. 

SPACE TELESCOPE SCIENCE INSTITUTE 

The Space Telescope Science Institute (STScI) 

oversees science operations for Goddard Space 

Flight Center. Among its functions are to: 

• Host astronomers 

• Evaluate proposals and choose observations 

programs 

• Schedule the selected observations and 

assist guest observers in their work 

• Generate an overall mission timeline and 

command sequences 

• Store and analyze science data from the 

telescope. 

STScI also monitors the telescope and science 

instruments for characteristics that could affect 

science data collection, such as instrument 

performance quality, pointing inaccuracies, and 

telescope focus. 

The flight operations team conducts mission 

operations from the STOCC at Goddard. 
MAY 2009 SM4 FACILITIES 85

Scientific Goals 

The Association of Universities for Research in 

Astronomy (AURA) operates STScI. AURA is a 

consortium of 29 United States universities that 

run several national facilities for astronomy. 

STScI helps conduct the science program to 

meet the overall scientific goals of the telescope 

program, set by the Institute and NASA in 

consultation with AURA’s Space Telescope 

Institute Council and committees representing 

the international astronomical community. 

STScI Software 

Computer hardware and software play an 

important role in STScI work, including a 

mission planning and scheduling system and a 

science data processing system. STScI also 

created a guide star catalog used to support the 

precise pointing requirements of the telescope 

pointing control subsystem. In addition, the 

Space Telescope Science Data Analysis 

Software (STSDAS) provides analytical tools for 

astronomers studying observational data. 

As part of the Planning and Scheduling System, 

the STScI Guide Star Selection System (GSSS) 

provides reference stars and other bright 

objects so the Fine Guidance Sensors (FGS) can 

point the telescope accurately. GSSS selects 

guide stars that can be located unambiguously 

in the sky when the sensors point the telescope. 

The guide star catalog has information on 

20 million celestial objects, created from 

1,477 photographic survey plates covering the 

entire sky. 

As STScI collects, edits, measures and archives 

science data, observers can use SDAS to analyze 

and interpret the data. 

Selecting Observation Proposals 

Astronomers worldwide may use the telescope. 

Any scientist may submit a proposal to STScI 

outlining an observing program and describing 

the scientific objectives and instruments 

required. 

STScI evaluates these requests for technical 

feasibility, conducts peer reviews and then 

chooses the highest ranked proposals. The final 

decision rests with the STScI director, advised 

by a review committee of astronomers and 

scientists from many institutions. 

Because individual astronomers and astronomy 

teams submit many more proposals than can 

possibly be accepted, the STScI encourages a 

team approach. 

Scheduling Telescope Observations 

The primary scheduling consideration is 

availability of a target, which may be limited by 

environmental and stay-light constraints. For 

example, a faint object occasionally must be 

observed when the telescope is in Earth’s 

shadow. The schedule takes into consideration 

system limits, observations that use more than 

one instrument, and required time for special 

observations. 

Data Analysis and Storage 

STScI is responsible for storing the massive 

amount of data collected by the telescope. The 

Hubble Data Archive catalog records the 

location and status of data as it pours into the 

storage banks. Observers can easily retrieve the 

stored data for examination or use data 

manipulation procedures created by the STScI. 

The European Space Agency provides 

approximately 15 staff members co-located 
86 SM4 FACILITIES MAY 2009

with STScI staff and operates its own data 

analysis facility in Garching, Germany. 

In addition to science data, the STScI stores 

engineering data. This is important for 

developing more efficient use of the telescope 

systems and for adjusting telescope operations 

based on engineering findings, for example, if 

an instrument provides unreliable data in 

certain temperature ranges. 

STScI processes all data within 24 hours after 

receipt. When STScI receives science data from 

PACOR, it automatically formats the data and 

verifies its quality. STScI also calibrates data to 

remove the instrument’s properties, such as a 

variation in the detector’s sensitivity across the 

data field. Then the software places the data in 

the archive where it can be retrieved 

electronically by an observer or archival 

researcher. 
SHUTTLE REFERENCE DATA 

MAY 2009 SHUTTLE REFERENCE DATA 87

SHUTTLE ABORT MODES 

Redundant Sequence Launch Sequencer 

(RSLS) Aborts 

These occur when the on-board shuttle 

computers detect a problem and command a 

halt in the launch sequence after taking over 

from the ground launch sequencer and before 

solid rocket booster ignition. 

Ascent Aborts 

Selection of an ascent abort mode may become 

necessary if there is a failure that affects vehicle 

performance, such as the failure of a space 

shuttle main engine or an orbital maneuvering 

system engine. Other failures requiring early 

termination of a flight, such as a cabin leak, 

might also require the selection of an abort 

mode. There are two basic types of ascent abort 

modes for space shuttle missions: intact aborts 

and contingency aborts. Intact aborts are 

designed to provide a safe return of the orbiter 

to a planned landing site. Contingency aborts 

are designed to permit flight crew survival 

following more severe failures when an intact 

abort is not possible. A contingency abort 

would generally result in a ditch operation. 

Intact Aborts 

There are four types of intact aborts: abort to 

orbit (ATO), abort once around (AOA), 

transoceanic abort landing (TAL) and return to 

launch site (RTLS). 

Return to Launch Site 

The RTLS abort mode is designed to allow the 

return of the orbiter, crew, and payload to the 

launch site, KSC, approximately 25 minutes 

after liftoff. 

The RTLS profile is designed to accommodate 

the loss of thrust from one space shuttle main 

engine between liftoff and approximately 

four minutes 20 seconds, after which not 

enough main propulsion system propellant 

remains to return to the launch site. An RTLS 

can be considered to consist of three stages – a 

powered stage, during which the space shuttle 

main engines are still thrusting; an external 

tank separation phase; and the glide phase, 

during which the orbiter glides to a landing at 

the KSC. The powered RTLS phase begins with 

the crew selection of the RTLS abort, after solid 

rocket booster separation. The crew selects the 

abort mode by positioning the abort rotary 

switch to RTLS and depressing the abort push 

button. The time at which the RTLS is selected 

depends on the reason for the abort. For 

example, a three-engine RTLS is selected at the 

last moment, about 3 minutes, 34 seconds into 

the mission; whereas an RTLS chosen due to an 

engine out at liftoff is selected at the earliest 

time, about 2 minutes, 20 seconds into the 

mission (after solid rocket booster separation). 

After RTLS is selected, the vehicle continues 

downrange to dissipate excess main propulsion 

system propellant. The goal is to leave only 

enough main propulsion system propellant to 

be able to turn the vehicle around, fly back 

toward the KSC and achieve the proper main 

engine cutoff conditions so the vehicle can glide 

to the KSC after external tank separation. 

During the downrange phase, a pitch-around 

maneuver is initiated (the time depends in part 

on the time of a space shuttle main engine 

failure) to orient the orbiter/external tank 

configuration to a heads-up attitude, pointing 

toward the launch site. At this time, the vehicle 

is still moving away from the launch site, but 
88 SHUTTLE REFERENCE DATA MAY 2009

the space shuttle main engines are now 

thrusting to null the downrange velocity. In 

addition, excess orbital maneuvering system 

and reaction control system propellants are 

dumped by continuous orbital maneuvering 

system and reaction control system engine 

thrustings to improve the orbiter weight and 

center of gravity for the glide phase and 

landing. 

The vehicle will reach the desired main engine 

cutoff point with less than 2 percent excess 

propellant remaining in the external tank. At 

main engine cutoff minus 20 seconds, a pitch 

down maneuver (called powered pitch-down) 

takes the mated vehicle to the required external 

tank separation attitude and pitch rate. After 

main engine cutoff has been commanded, the 

external tank separation sequence begins, 

including a reaction control system maneuver 

that ensures that the orbiter does not recontact 

the external tank and that the orbiter has 

achieved the necessary pitch attitude to begin 

the glide phase of the RTLS. 

After the reaction control system maneuver has 

been completed, the glide phase of the RTLS 

begins. From then on, the RTLS is handled 

similarly to a normal entry. 

Transoceanic Abort Landing 

The TAL abort mode was developed to 

improve the options available when a space 

shuttle main engine fails after the last RTLS 

opportunity but before the first time that an 

AOA can be accomplished with only two space 

shuttle main engines or when a major orbiter 

system failure, for example, a large cabin 

pressure leak or cooling system failure, occurs 

after the last RTLS opportunity, making it 

imperative to land as quickly as possible. 

In a TAL abort, the vehicle continues on a 

ballistic trajectory across the Atlantic Ocean to 

land at a predetermined runway. Landing 

occurs about 45 minutes after launch. The 

landing site is selected near the normal ascent 

ground track of the orbiter to make the most 

efficient use of space shuttle main engine 

propellant. The landing site also must have the 

necessary runway length, weather conditions 

and U.S. State Department approval. The three 

landing sites that have been identified for a 

launch are Zaragoza, Spain; Moron, Spain; and 

Istres, France. 

To select the TAL abort mode, the crew must 

place the abort rotary switch in the TAL/AOA 

position and depress the abort push button 

before main engine cutoff (Depressing it after 

main engine cutoff selects the AOA abort 

mode). The TAL abort mode begins sending 

commands to steer the vehicle toward the plane 

of the landing site. It also rolls the vehicle 

heads up before main engine cutoff and sends 

commands to begin an orbital maneuvering 

system propellant dump (by burning the 

propellants through the orbital maneuvering 

system engines and the reaction control system 

engines). This dump is necessary to increase 

vehicle performance (by decreasing weight) to 

place the center of gravity in the proper place 

for vehicle control and to decrease the vehicle’s 

landing weight. TAL is handled like a normal 

entry. 

Abort to Orbit 

An ATO is an abort mode used to boost the 

orbiter to a safe orbital altitude when 

performance has been lost and it is impossible 

to reach the planned orbital altitude. If a space 

shuttle main engine fails in a region that results 

in a main engine cutoff under speed, the MCC 

will determine that an abort mode is necessary 
MAY 2009 SHUTTLE REFERENCE DATA 89

and will inform the crew. The orbital 

maneuvering system engines would be used to 

place the orbiter in a circular orbit. 

Abort Once Around 

The AOA abort mode is used in cases in which 

vehicle performance has been lost to such an 

extent that either it is impossible to achieve a 

viable orbit or not enough orbital maneuvering 

system propellant is available to accomplish the 

orbital maneuvering system thrusting 

maneuver to place the orbiter on orbit and the 

deorbit thrusting maneuver. In addition, an 

AOA is used in cases in which a major systems 

problem (cabin leak, loss of cooling) makes it 

necessary to land quickly. In the AOA abort 

mode, one orbital maneuvering system 

thrusting sequence is made to adjust the 

post-main engine cutoff orbit so a second 

orbital maneuvering system thrusting sequence 

will result in the vehicle deorbiting and landing 

at the AOA landing site (White Sands, N.M.; 

Edwards Air Force Base, Calif.; or the Kennedy 

Space Center, Fla). Thus, an AOA results in the 

orbiter circling the Earth once and landing 

about 90 minutes after liftoff. 

After the deorbit thrusting sequence has been 

executed, the flight crew flies to a landing at the 

planned site much as it would for a nominal 

entry. 

Contingency Aborts 

Contingency aborts are caused by loss of more 

than one main engine or failures in other 

systems. Loss of one main engine while 

another is stuck at a low thrust setting also may 

necessitate a contingency abort. Such an abort 

would maintain orbiter integrity for in-flight 

crew escape if a landing cannot be achieved at a 

suitable landing field. 

Contingency aborts due to system failures other 

than those involving the main engines would 

normally result in an intact recovery of vehicle 

and crew. Loss of more than one main engine 

may, depending on engine failure times, result 

in a safe runway landing. However, in most 

three-engine-out cases during ascent, the 

orbiter would have to be ditched. The inflight 

crew escape system would be used before 

ditching the orbiter. 

Abort Decisions 

There is a definite order of preference for the 

various abort modes. The type of failure and the 

time of the failure determine which type of abort 

is selected. In cases where performance loss is 

the only factor, the preferred modes are ATO, 

AOA, TAL and RTLS, in that order. The mode 

chosen is the highest one that can be completed 

with the remaining vehicle performance. 

In the case of some support system failures, 

such as cabin leaks or vehicle cooling problems, 

the preferred mode might be the one that will 

end the mission most quickly. In these cases, 

TAL or RTLS might be preferable to AOA or 

ATO. A contingency abort is never chosen if 

another abort option exists. 

Mission Control Houston is prime for calling 

these aborts because it has a more precise 

knowledge of the orbiter’s position than the 

crew can obtain from on-board systems. Before 

main engine cutoff, Mission Control makes 

periodic calls to the crew to identify which 

abort mode is (or is not) available. If ground 

communications are lost, the flight crew has 

on-board methods, such as cue cards, dedicated 

displays and display information, to determine 

the abort region. Which abort mode is selected 

depends on the cause and timing of the failure 

causing the abort and which mode is safest or 
90 SHUTTLE REFERENCE DATA MAY 2009

improves mission success. If the problem is a 

space shuttle main engine failure, the flight 

crew and Mission Control Center select the best 

option available at the time a main engine fails. 

If the problem is a system failure that 

jeopardizes the vehicle, the fastest abort mode 

that results in the earliest vehicle landing is 

chosen. RTLS and TAL are the quickest options 

(35 minutes), whereas an AOA requires about 

90 minutes. Which of these is selected depends 

on the time of the failure with three good space 

shuttle main engines. 

The flight crew selects the abort mode by 

positioning an abort mode switch and 

depressing an abort push button. 

SHUTTLE ABORT HISTORY 

RSLS Abort History 

(STS-41 D) June 26, 1984 

The countdown for the second launch attempt 

for Discovery’s maiden flight ended at T-4 

seconds when the orbiter’s computers detected 

a sluggish valve in main engine No. 3. The 

main engine was replaced and Discovery was 

finally launched on Aug. 30, 1984. 

(STS-51 F) July 12, 1985 

The countdown for Challenger’s launch was 

halted at T-3 seconds when on-board 

computers detected a problem with a coolant 

valve on main engine No. 2. The valve was 

replaced and Challenger was launched on 

July 29, 1985. 

(STS-55) March 22, 1993 

The countdown for Columbia’s launch was 

halted by on-board computers at T-3 seconds 

following a problem with purge pressure 

readings in the oxidizer preburner on main 

engine No. 2. Columbia’s three main engines 

were replaced on the launch pad, and the flight 

was rescheduled behind Discovery’s launch on 

STS-56. Columbia finally launched on 

April 26, 1993. 

(STS-51) Aug. 12, 1993 

The countdown for Discovery’s third launch 

attempt ended at the T-3 second mark when 

onboard computers detected the failure of one 

of four sensors in main engine No. 2 which 

monitor the flow of hydrogen fuel to the 

engine. All of Discovery’s main engines were 

ordered replaced on the launch pad, delaying 

the shuttle’s fourth launch attempt until Sept. 

12, 1993. 

(STS-68) Aug. 18, 1994 

The countdown for Endeavour’s first launch 

attempt ended 1.9 seconds before liftoff when 

on-board computers detected higher than 

acceptable readings in one channel of a sensor 

monitoring the discharge temperature of the 

high pressure oxidizer turbopump in main 

engine No. 3. A test firing of the engine at the 

Stennis Space Center in Mississippi on 

September 2nd confirmed that a slight drift in a 

fuel flow meter in the engine caused a slight 

increase in the turbopump’s temperature. The 

test firing also confirmed a slightly slower start 

for main engine No. 3 during the pad abort, 

which could have contributed to the higher 

temperatures. After Endeavour was brought 

back to the Vehicle Assembly Building to be 

outfitted with three replacement engines, 

NASA managers set Oct. 2 as the date for 

Endeavour’s second launch attempt. 
MAY 2009 SHUTTLE REFERENCE DATA 91

Abort to Orbit History 

(STS-51 F) July 29, 1985 

After an RSLS abort on July 12, 1985, 

Challenger was launched on July 29, 1985. 

Five minutes and 45 seconds after launch, a 

sensor problem resulted in the shutdown of 

center engine No. 1, resulting in a safe “abort to 

orbit” and successful completion of the mission. 

SPACE SHUTTLE MAIN ENGINES 

Developed in the 1970s by NASA’s Marshall 

Space Flight Center, MSFC in Huntsville, Ala., 

the space shuttle main engine is the most 

advanced liquid-fueled rocket engine ever built. 

Every space shuttle main engine is tested and 

proven flight worthy at NASA’s Stennis Space 

Center in south Mississippi, before installation 

on an orbiter. Its main features include variable 

thrust, high performance reusability, high 

redundancy and a fully integrated engine 

controller. 

The shuttle’s three main engines are mounted 

on the orbiter aft fuselage in a triangular 

pattern. Spaced so that they are movable 

during launch, the engines are used, in 

conjunction with the solid rocket boosters, to 

steer the shuttle vehicle. 

Each of these powerful main engines is 14 feet 

long, weighs about 7,000 pounds and is 7.5 feet 

in diameter at the end of its nozzle. 

The engines operate for about 8.5 minutes 

during liftoff and ascent, burning more than 

500,000 gallons of super-cold liquid hydrogen 

and liquid oxygen propellants stored in the 

external tank attached to the underside of the 

shuttle. The engines shut down just before the 

shuttle, traveling at about 17,000 miles per 

hour, reaches orbit. 

The main engine operates at greater 

temperature extremes than any mechanical 

system in common use today. The fuel, 

liquefied hydrogen at -423 degrees Fahrenheit, 

is the second coldest liquid on Earth. When it 

and the liquid oxygen are combusted, the 

temperature in the main combustion chamber is 

6,000 degrees Fahrenheit, hotter than the 

boiling point of iron. 

The main engines use a staged combustion 

cycle so that all propellants entering the engines 

are used to produce thrust, or power, more 

efficiently than any previous rocket engine. In 

a staged combustion cycle, propellants are first 

burned partially at high pressure and relatively 

low temperature, and then burned completely 

at high temperature and pressure in the main 

combustion chamber. The rapid mixing of the 

propellants under these conditions is so 

complete that 99 percent of the fuel is burned. 

At normal operating level, each engine 

generates 490,847 pounds of thrust, measured 

in a vacuum. Full power is 512,900 pounds of 

thrust; minimum power is 316,100 pounds of 

thrust. 

The engine can be throttled by varying the 

output of the pre-burners, thus varying the 

speed of the high-pressure turbopumps and, 

therefore, the flow of the propellant. 

At about 26 seconds into ascent, the main 

engines are throttled down to 316,000 pounds 

of thrust to keep the dynamic pressure on the 

vehicle below a specified level,about 

580 pounds per square foot, known as max q. 

Then, the engines are throttled back up to 

normal operating level at about 60 seconds. 

This reduces stress on the vehicle. The main 

engines are throttled down again at about 

seven minutes, 40 seconds into the mission to 
92 SHUTTLE REFERENCE DATA MAY 2009

maintain three g’s, three times the Earth’s 

gravitational pull, reducing stress on the crew 

and the vehicle. This acceleration level is about 

one-third the acceleration experienced on 

previous crewed space vehicles. 

About 10 seconds before main engine cutoff, or 

MECO, the cutoff sequence begins. About 

three seconds later the main engines are 

commanded to begin throttling at 10 percent 

thrust per second until they achieve 65 percent 

thrust. This is held for about 6.7 seconds, and 

the engines are shut down. 

The engine performance has the highest thrust 

for its weight of any engine yet developed. In 

fact, one space shuttle main engine generates 

sufficient thrust to maintain the flight of two 

and one-half Boeing 747 airplanes. 

The space shuttle main engine also is the first 

rocket engine to use a built-in electronic digital 

controller, or computer. The controller accepts 

commands from the orbiter for engine start, 

change in throttle, shutdown and monitoring of 

engine operation. 

NASA continues to increase the reliability and 

safety of shuttle flights through a series of 

enhancements to the space shuttle main 

engines. The engines were modified in 1988, 

1995, 1998, 2001 and 2007. Modifications 

include new high-pressure fuel and oxidizer 

turbopumps that reduce maintenance and 

operating costs of the engine, a two-duct 

powerhead that reduces pressure and 

turbulence in the engine, and a single-coil heat 

exchanger that lowers the number of post flight 

inspections required. Another modification 

incorporates a large-throat main combustion 

chamber that improves the engine’s reliability 

by reducing pressure and temperature in the 

chamber. 

The most recent engine enhancement is the 

Advanced Health Management System, or 

AHMS, which made its first flight in 2007. 

AHMS is a controller upgrade that provides 

new monitoring and insight into the health of 

the two most complex components of the space 

shuttle main engine—the high pressure fuel 

turbopump and the high pressure oxidizer 

turbopump. New advanced digital signal 

processors monitor engine vibration and have 

the ability to shut down an engine if vibration 

exceeds safe limits. AHMS was developed by 

engineers at Marshall. 

After the orbiter lands, the engines are removed 

and returned to a processing facility at 

Kennedy Space Center, Fla., where they are 

rechecked and readied for the next flight. Some 

components are returned to the main engine’s 

prime contractor, Pratt & Whitney Rocketdyne, 

West Palm Beach, Fla., for regular maintenance. 

The main engines are designed to operate for 

7.5 accumulated hours. 

SPACE SHUTTLE SOLID ROCKET 

BOOSTERS 

The combination of reusable solid rocket motor 

segments and solid rocket booster 

subassemblies makes up the flight 

configuration of the space shuttle solid rocket 

boosters, or SRBs. The two SRBs provide the 

main thrust to lift the space shuttle off the 

launch pad and up to an altitude of about 

150,000 feet, or 28 miles. The two SRBs carry 

the entire weight of the external tank and 

orbiter and transmit the weight load through 

their structure to the mobile launcher platform. 

The primary elements of each booster are the 

motor, including case, propellant, igniter and 

nozzle; separation systems; operational flight 

instrumentation; recovery avionics; 
MAY 2009 SHUTTLE REFERENCE DATA 93

pyrotechnics; deceleration system; thrust vector 

control system; and range safety destruct 

system. 

Each booster is attached to the external tank at 

the SRB aft frame by two lateral sway braces 

and a diagonal attachment. The forward end of 

each SRB is attached to the external tank at the 

forward end of the SRB forward skirt. On the 

launch pad, each booster also is attached to the 

mobile launcher platform at the aft skirt by four 

bolts and nuts that are severed by small 

explosives at liftoff. 

Each booster has a sea level thrust of about 

3.3 million pounds at launch. The SRBs are 

ignited after the three space shuttle main 

engines’ thrust level is verified. They provide 

71.4 percent of the thrust at liftoff and during 

first-stage ascent. Seventy-five seconds after 

separation, SRB apogee occurs at an altitude of 

about 220,000 feet, or 40 miles. Impact occurs 

in the ocean about 140 miles downrange. 

The SRBs are used as matched pairs, each made 

up of four solid rocket motor segments. They 

are matched by loading each of the four motor 

segments from the same batches of propellant 

ingredients to minimize any thrust imbalance. 

The segmented-casing design assures 

maximum flexibility in fabrication and ease of 

transportation and handling. Each segment is 

shipped to the launch site on a heavy-duty rail 

car with a specially built cover. 

Reusable Solid Rocket Motor (RSRM) 

ATK Launch Systems of Brigham City, Utah, 

manufactures the Space Shuttle Reusable Solid 

Rocket Motor (RSRM) at its Utah facility. The 

RSRM is the largest solid rocket motor ever to 

fly, the only solid rocket motor rated for human 

flight and the first designed for reuse, one of 

the most important cost-saving factors in the 

nation’s space program. 

Each RSRM consists of four rocket motor 

segments, thrust vector control and an aft exit 

cone assembly. Each motor is just over 126 feet 

long and 12 feet in diameter. Of the motor’s 

total weight of 1.25 million pounds, propellant 

accounts for 1.1 million pounds. 

Approximately 110,000 quality-control 

inspections, in addition to static tests, are 

conducted on each RSRM flight set to verify 

flawless operation. 

Each space shuttle launch requires the boost of 

two RSRMs to lift the 4.5-million-pound shuttle 

vehicle. From ignition to the end of burn, about 

123 seconds later, each RSRM generates an 

average thrust of 2.6 million pounds. By the 

time the twin SRBs have completed their task, 

the space shuttle orbiter has reached an altitude 

of 28 miles and is traveling at a speed in excess 

of 3,000 miles per hour. Before retirement, each 

RSRM can be used as many as 20 times. 

The propellant mixture in each SRB motor 

consists of: ammonium perchlorate, an 

oxidizer; aluminum fuel; iron oxide, a catalyst; 

a polymer, which is a binder that holds the 

mixture together,; and an epoxy curing agent. 

The propellant has the consistency of a pencil 

eraser. It has a molded internal geometry 

designed to provide required performance. 

This configuration provides high thrust at 

ignition and then reduces the thrust by about 

one-third 50 seconds after liftoff to prevent 

overstressing the vehicle during maximum 

dynamic pressure. 

The RSRM segments are shipped by rail from 

ATK’s Utah facility to the Kennedy Space 

Center, Fla. At KSC, United Space Alliance 

joins the segments with the forward assembly, 
94 SHUTTLE REFERENCE DATA MAY 2009

aft skirt, frustum, and nose cap. The 

subassemblies contain the booster guidance 

system, the hydraulics system that steers the 

nozzles, Booster Separation Motors built by 

ATK, and parachutes. 

Following the Challenger accident, detailed 

structural analyses were performed on critical 

structural elements of the SRB. Analyses were 

primarily focused in areas where anomalies had 

been noted during postflight inspection of 

recovered hardware. 

One of these areas was the attach ring where 

the SRBs connect to the external tank. Areas of 

distress were noted in some of the fasteners 

where the ring attaches to the SRB motor case. 

The distress was attributed to the high loads 

encountered during water impact. To correct 

the situation and ensure higher strength 

margins during ascent, the attach ring was 

redesigned to encircle the motor case 

completely. Previously, the attach ring formed 

a “C” and encircled the motor case 270 degrees. 

Additionally, special structural tests were done 

on the aft skirt. During this test program, an 

anomaly occurred in a critical weld between the 

hold-down post and skin of the skirt. A 

redesign was implemented to add 

reinforcement brackets and fittings in the aft 

ring of the skirt. 

These two modifications added about 

450 pounds to the weight of each SRB. 

Beginning with the STS-8 mission, the nozzle 

expansion ratio of each booster is 7-to-79. The 

nozzle is gimbaled for thrust vector, or 

direction, control. Each SRB has its own 

redundant auxiliary power units and hydraulic 

pumps. The all-axis gimbaling capability is 

8 degrees. Each nozzle has a carbon cloth liner 

that erodes and chars during firing. The nozzle 

is a convergent-divergent, movable design in 

which an aft pivot-point flexible bearing is the 

gimbal mechanism. 

The cone-shaped aft skirt supports the weight 

of the entire vehicle as it rests on the mobile 

launcher platform. The four aft separation 

motors are mounted on the skirt. The aft 

section contains: avionics; a thrust vector 

control system that consists of two auxiliary 

power units and hydraulic pumps; hydraulic 

systems; and a nozzle extension jettison system. 

The forward section of each booster contains 

avionics, a sequencer, forward separation 

motors, a nose cone separation system, drogue 

and main parachutes, a recovery beacon, a 

recovery light, a parachute camera on selected 

flights and a range safety system. 

Each SRB has two integrated electronic 

assemblies, one forward and one aft. After 

burnout, the forward assembly turns on the 

recovery aids and initiates the release of the 

nose cap and frustum, a transition piece 

between the nose cone and solid rocket motor. 

The aft assembly, mounted in the external tankto-SRB attach ring, connects with the forward 

assembly and the shuttle avionics systems for 

SRB ignition commands and nozzle thrust 

vector control. Each integrated electronic 

assembly has a multiplexer/demultiplexer, 

which sends or receives more than one 

message, signal or unit of information on a 

single communication channel. 

Eight Booster Separation Motors, four in the 

nose frustum and four in the aft skirt of each 

SRB, thrust for 1.02 seconds when the SRBs 

separate from the external tank. Each solid 

rocket separation motor is 31.1 inches long and 

12.8 inches in diameter. 
MAY 2009 SHUTTLE REFERENCE DATA 95

After separation from the tank, the boosters 

descend. At a predetermined altitude, 

parachutes are deployed to decelerate them for 

a safe splashdown in the ocean. Just prior to 

splashdown, the aft exit cones, or nozzle 

extensions, are separated from the vehicles to 

reduce water impact loads. Splashdown occurs 

approximately 162 miles from the launch site. 

Location aids are provided for each SRB, 

frustum and drogue chutes, and main 

parachutes. These include a transmitter, 

antenna, strobe/converter, battery and 

salt-water switch electronics. The location aids 

are designed for a minimum operating life of 

72 hours and, when refurbished, are considered 

usable up to 20 times. The flashing light is an 

exception. It has an operating life of 280 hours. 

The battery is used only once. 

The recovery crew retrieves the SRBs, frustum 

and drogue chutes, and main parachutes. The 

nozzles are plugged, the solid rocket motors are 

dewatered, and the SRBs are towed back to the 

launch site. Each booster is removed from the 

water, and its components are disassembled 

and washed with fresh and deionized water to 

limit salt-water corrosion. The motor segments, 

igniter and nozzle are shipped back to ATK in 

Utah for refurbishment. The SRB nose caps and 

nozzle extensions are not recovered. 

Each SRB incorporates a range safety system 

that includes a battery power source, receiver 

and decoder, antennas, and ordnance. 

Hold-Down Posts 

Each SRB has four hold-down posts that fit into 

corresponding support posts on the mobile 

launcher platform. Hold-down bolts secure the 

SRB and launcher platform posts together. 

Each bolt has a nut at each end, but only the top 

nut is frangible. The top nut contains two 

NASA standard detonators, or NSDs, which are 

ignited at solid rocket motor ignition 

commands. 

When the two NSDs are ignited at each 

hold-down, the hold-down bolt travels 

downward because of the release of tension in 

the bolt (pretensioned before launch), NSD gas 

pressure and gravity. The bolt is stopped by 

the stud deceleration stand, which contains 

sand. The SRB bolt is 28 inches long and 

3.5 inches in diameter. The frangible nut is 

captured in a blast container. 

The solid rocket motor ignition commands are 

issued by the orbiter’s computers through the 

master events controllers to the hold-down 

pyrotechnic initiator controllers, or PICs, on the 

mobile launcher platform. They provide the 

ignition to the hold-down NSDs. The launch 

processing system monitors the SRB hold-down 

PICs for low voltage during the last 16 seconds 

before launch. PIC low voltage will initiate a 

launch hold. 

SRB Ignition 

SRB ignition can occur only when a manual 

lock pin from each SRB safe and arm device has 

been removed. The ground crew removes the 

pin during prelaunch activities. At T minus 

five minutes, the SRB safe and arm device is 

rotated to the arm position. The solid rocket 

motor ignition commands are issued when the 

three SSMEs are at or above 90 percent rated 

thrust, no SSME fail and/or SRB ignition PIC 

low voltage is indicated, and there are no holds 

from the Launch Processing System, or LPS. 

The solid rocket motor ignition commands are 

sent by the orbiter computers through the 

master events controllers, or MECs, to the safe 

and arm device NSDs in each SRB. A 

programmable interval clock, or PIC, 
96 SHUTTLE REFERENCE DATA MAY 2009

single-channel capacitor discharge device 

controls the firing of each pyrotechnic device. 

Three signals must be present simultaneously 

for the PIC to generate the pyro firing output. 

These signals – arm, fire 1 and fire 2 – originate 

in the orbiter General Purpose Computers, or 

GPCs, and are transmitted to the MECs. The 

MECs reformat them to 28-volt dc signals for 

the programmable interval clock. The arm 

signal charges the PIC capacitor to 40 volts dc. 

The fire 2 commands cause the redundant 

NSDs to fire through a thin barrier seal down a 

flame tunnel. This ignites a pyro booster 

charge, which is retained in the safe and arm 

device behind a perforated plate. The booster 

charge ignites the propellant in the igniter 

initiator; and combustion products of this 

propellant ignite the solid rocket motor 

initiator, which fires down the length of the 

solid rocket motor, igniting the solid rocket 

motor propellant. 

The GPC launch sequence also controls certain 

critical main propulsion system valves and 

monitors the engine-ready indications from the 

SSMEs. The Main Propulsion System, or MPS, 

start commands are issued by the on-board 

computers at T minus 6.6 seconds in a 

staggered start – engine three, engine two, 

engine one – all about within 0.25 of a second, 

and the sequence monitors the thrust buildup 

of each engine. All three SSMEs must reach the 

required 90 percent thrust within three seconds, 

otherwise, an orderly shutdown is commanded 

and safing functions are initiated. 

Normal thrust buildup to the required 90 

percent thrust level will result in the SSMEs 

being commanded to the liftoff position at 

T minus three seconds as well as the fire 1 

command being issued to arm the SRBs. At 

T minus three seconds, the vehicle base 

bending load modes are allowed to initialize, 

with a movement of 25.5 inches measured at 

the tip of the external tank, with movement 

towards the external tank. 

At T minus zero, the two SRBs are ignited 

under command of the four onboard 

computers; separation of the four explosive 

bolts on each SRB is initiated; the two T-0 

umbilicals, one on each side of the spacecraft, 

are retracted; the onboard master timing unit, 

event timer and mission event timers are 

started; the three SSMEs are at 100 percent; and 

the ground launch sequence is terminated. 

The solid rocket motor thrust profile is tailored 

to reduce thrust during the maximum dynamic 

pressure region. 

Electrical Power Distribution 

Electrical power distribution in each SRB 

consists of orbiter-supplied main dc bus power 

to each SRB via SRB buses A, B and C. In 

addition, orbiter main dc bus C supplies 

backup power to SRB buses A and B, and 

orbiter bus B supplies backup power to SRB 

bus C. This electrical power distribution 

arrangement allows all SRB buses to remain 

powered in the event one orbiter main bus fails. 

The nominal dc voltage is 28 volts dc, with an 

upper limit of 32 volts dc and a lower limit of 

24 volts dc. 

Hydraulic Power Units 

There are two self-contained, independent 

HPUs on each SRB. Each HPU consists of an 

auxiliary power unit, fuel supply module, 

hydraulic pump, hydraulic reservoir and 

hydraulic fluid manifold assembly. The 

auxiliary power units, or APUs, are fueled by 

hydrazine and generate mechanical shaft power 

to a hydraulic pump that produces hydraulic 
MAY 2009 SHUTTLE REFERENCE DATA 97

pressure for the SRB hydraulic system. The two 

separate HPUs and two hydraulic systems are 

located on the aft end of each SRB between the 

SRB nozzle and aft skirt. The HPU components 

are mounted on the aft skirt between the rock 

and tilt actuators. The two systems operate 

from T minus 28 seconds until SRB separation 

from the orbiter and external tank. The two 

independent hydraulic systems are connected 

to the rock and tilt servoactuators. 

The APU controller electronics are located in 

the SRB aft integrated electronic assemblies on 

the aft external tank attach rings. 

The APUs and their fuel systems are isolated 

from each other. Each fuel supply module tank 

contains 22 pounds of hydrazine. The fuel tank 

is pressurized with gaseous nitrogen at 400 psi, 

which provides the force to expel the fuel from 

the tank to the fuel distribution line, 

maintaining a positive fuel supply to the APU 

throughout its operation. 

The fuel isolation valve is opened at APU 

startup to allow fuel to flow to the APU fuel 

pump and control valves and then to the gas 

generator. The gas generator’s catalytic action 

decomposes the fuel and creates a hot gas. It 

feeds the hot gas exhaust product to the APU 

two-stage gas turbine. Fuel flows primarily 

through the startup bypass line until the APU 

speed is such that the fuel pump outlet pressure 

is greater than the bypass line’s. Then all the 

fuel is supplied to the fuel pump. 

The APU turbine assembly provides 

mechanical power to the APU gearbox. The 

gearbox drives the APU fuel pump, hydraulic 

pump and lube oil pump. The APU lube oil 

pump lubricates the gearbox. The turbine 

exhaust of each APU flows over the exterior of 

the gas generator, cooling it, and is then 

directed overboard through an exhaust duct. 

When the APU speed reaches 100 percent, the 

APU primary control valve closes, and the APU 

speed is controlled by the APU controller 

electronics. If the primary control valve 

logic fails to the open state, the secondary 

control valve assumes control of the APU at 

112 percent speed. Each HPU on an SRB is 

connected to both servoactuators on that SRB. 

One HPU serves as the primary hydraulic 

source for the servoactuator, and the other 

HPU serves as the secondary hydraulics for 

the servoactuator. Each servoactuator has a 

switching valve that allows the secondary 

hydraulics to power the actuator if the primary 

hydraulic pressure drops below 2,050 psi. A 

switch contact on the switching valve will close 

when the valve is in the secondary position. 

When the valve is closed, a signal is sent to the 

APU controller that inhibits the 100 percent 

APU speed control logic and enables the 

112 percent APU speed control logic. The 

100 percent APU speed enables one APU/ 

HPU to supply sufficient operating hydraulic 

pressure to both servoactuators of that SRB. 

The APU 100 percent speed corresponds to 

72,000 rpm, 110 percent to 79,200 pm, and 

112 percent to 80,640 rpm. 

The hydraulic pump speed is 3,600 rpm and 

supplies hydraulic pressure of 3,050, plus or 

minus 50, psi. A high-pressure relief valve 

provides overpressure protection to the 

hydraulic system and relieves at 3,750 psi. 

The APUs/HPUs and hydraulic systems are 

reusable for 20 missions. 
98 SHUTTLE REFERENCE DATA MAY 2009

Thrust Vector Control 

Each SRB has two hydraulic gimbal 

servoactuators, one for rock and one for tilt. 

The servoactuators provide the force and 

control to gimbal the nozzle for thrust vector 

control. 

The space shuttle ascent thrust vector control, 

or ATVC, portion of the flight control system 

directs the thrust of the three shuttle main 

engines and the two SRB nozzles to control 

shuttle attitude and trajectory during liftoff and 

ascent. Commands from the guidance system 

are transmitted to the ATVC drivers, which 

transmit signals proportional to the commands 

to each servoactuator of the main engines and 

SRBs. Four independent flight control system 

channels and four ATVC channels control six 

main engine and four SRB ATVC drivers, with 

each driver controlling one hydraulic port on 

each main and SRB servoactuator. 

Each SRB servoactuator consists of four 

independent, two-stage servovalves that 

receive signals from the drivers. Each 

servovalve controls one power spool in each 

actuator, which positions an actuator ram and 

the nozzle to control the direction of thrust. 

The four servovalves in each actuator provide a 

force-summed majority voting arrangement to 

position the power spool. With four identical 

commands to the four servovalves, the actuator 

force-sum action prevents a single erroneous 

command from affecting power ram motion. If 

the erroneous command persists for more than 

a predetermined time, differential pressure 

sensing activates a selector valve to isolate and 

remove the defective servovalve hydraulic 

pressure, permitting the remaining channels 

and servovalves to control the actuator ram 

spool. 

Failure monitors are provided for each channel 

to indicate which channel has been bypassed. 

An isolation valve on each channel provides the 

capability of resetting a failed or bypassed 

channel. 

Each actuator ram is equipped with transducers 

for position feedback to the thrust vector 

control system. Within each servoactuator ram 

is a splashdown load relief assembly to cushion 

the nozzle at water splashdown and prevent 

damage to the nozzle flexible bearing. 

SRB Rate Gyro Assemblies 

Each SRB contains two RGAs, with each RGA 

containing one pitch and one yaw gyro. These 

provide an output proportional to angular rates 

about the pitch and yaw axes to the orbiter 

computers and guidance, navigation and 

control system during first-stage ascent flight in 

conjunction with the orbiter roll rate gyros until 

SRB separation. At SRB separation, a 

switchover is made from the SRB RGAs to the 

orbiter RGAs. 

The SRB RGA rates pass through the orbiter 

flight aft multiplexers/demultiplexers to the 

orbiter GPCs. The RGA rates are then 

mid-value-selected in redundancy management 

to provide SRB pitch and yaw rates to the 

user software. The RGAs are designed for 

20 missions. 

SRB Separation 

SRB separation is initiated when the three solid 

rocket motor chamber pressure transducers are 

processed in the redundancy management 

middle value select and the head-end chamber 

pressure of both SRBs is less than or equal to 

50 psi. A backup cue is the time elapsed from 

booster ignition. 
MAY 2009 SHUTTLE REFERENCE DATA 99

The separation sequence is initiated, 

commanding the thrust vector control actuators 

to the null position and putting the main 

propulsion system into a second stage 

configuration 0.8 second from sequence 

initialization, which ensures the thrust of each 

SRB is less than 100,000 pounds. Orbiter yaw 

attitude is held for four seconds, and SRB thrust 

drops to less than 60,000 pounds. The SRBs 

separate from the external tank within 

30 milliseconds of the ordnance firing 

command. 

The forward attachment point consists of a ball 

on the SRB and socket on the external tank held 

together by one bolt. The bolt contains one 

NSD pressure cartridge at each end. The 

forward attachment point also carries the Range 

Safety System, or RSS, cross-strap wiring 

connecting each SRB RSS and the ET RSS with 

each other. 

The aft attachment points consist of three 

separate struts, upper, diagonal, and lower. 

Each strut contains one bolt with an NSD 

pressure cartridge at each end. The upper strut 

also carries the umbilical interface between its 

SRB and the external tank and on to the orbiter. 

There are four Booster Separation Motors, or 

BSMs on each end of each SRB. The BSMs 

separate the SRBs from the external tank. The 

solid rocket motors in each cluster of four are 

ignited by firing redundant NSD pressure 

cartridges into redundant confined detonating 

fuse manifolds. The separation commands 

issued from the orbiter by the SRB separation 

sequence initiate the redundant NSD pressure 

cartridge in each bolt and ignite the BSMs to 

achieve a clean separation 

SRB Cameras 

A new camera, the External Tank Observation 

Camera, was added on the first Return to Flight 

mission. Named because it was originally 

certified to give NASA engineers a closer look 

at the insulating foam on the external tank’s 

inter-tank, the mid-section that joins the liquid 

hydrogen and liquid oxygen tanks. It consists 

of an off-the-shelf SuperCircuits PC 17 video 

camera and Sony mini-DV tape recorder 

positioned in each forward skirt section of the 

two boosters and offers a view of the Orbiter’s 

nose, the tank’s intertank and, at separation, the 

booster opposite the camera. 

The camera’s 2.5 mm lens provides a wideangle, 90 degree horizontal field of view. 

Recording begins at launch and continues until 

after drogue parachute deployment, when the 

recorder switches over to a second identical 

camera looking out the top to record main 

parachute deployment. Audio is also recorded, 

which allows some correlation between the 

video and various flight events. The recorder 

battery pack is a 7.2 volt Lithium Ion battery 

which supports 90 minutes of operation, 

enough to support launch and then descent 

back to the Atlantic Ocean. The camera battery 

pack is a 24V Ni-Cad battery pack. 

Video from the cameras is available for 

engineering review approximately 24 hours 

after the arrival of the boosters on the dock at 

Kennedy Space Center, usually about 52 hours 

after the launch. 

Redesigned Booster Separation Motors 

Redesigned Booster Separation Motors will fly 

the first time in both forward and aft locations 

on STS-125. As a result of vendor viability and 

manifest support issues, space shuttle BSMs are 

now being manufactured by ATK. The igniter 
100 SHUTTLE REFERENCE DATA MAY 2009

has been redesigned and other changes include 

material upgrades driven by obsolescence 

issues and improvements to process and 

inspection techniques. 

As before, eight BSMs are located on each 

booster, four on the forward section and four 

on the aft skirt. Once the SRBs have completed 

their flight, the eight BSMs are fired to jettison 

the boosters away from the orbiter and external 

tank, allowing the solid rocket motors to 

parachute to Earth and be reused. 

SPACE SHUTTLE SUPER LIGHT WEIGHT 

TANK (SLWT) 

The super lightweight external tank (SLWT) 

made its first shuttle flight June 2, 1998, on 

mission STS-91. The SLWT is 7,500 pounds 

lighter than the standard external tank. The 

lighter weight tank allows the shuttle to deliver 

International Space Station elements (such as 

the service module) into the proper orbit. 

The SLWT is the same size as the previous 

design. But the liquid hydrogen tank and the 

liquid oxygen tank are made of aluminum 

lithium, a lighter, stronger material than the 

metal alloy used for the shuttle’s current tank. 

The tank’s structural design has also been 

improved, making it 30 percent stronger and 

5 percent less dense. 

The SLWT, like the standard tank, is 

manufactured at Michoud Assembly, near 

New Orleans, by Lockheed Martin. 

The 154-foot-long external tank is the largest 

single component of the space shuttle. It stands 

taller than a 15-story building and has a 

diameter of about 27 feet. The external tank 

holds over 530,000 gallons of liquid hydrogen 

and liquid oxygen in two separate tanks. The 

hydrogen (fuel) and liquid oxygen (oxidizer) 

are used as propellants for the shuttle’s three 

main engines. 

EXTERNAL TANK 

The 154-foot-long external tank is the largest 

single component of the space shuttle. It stands 

taller than a 15-story building and has a 

diameter of about 27 feet. The external tank 

holds more than 530,000 gallons of liquid 

hydrogen and liquid oxygen in two separate 

tanks, the forward liquid oxygen tank and the 

aft liquid hydrogen tank. An unpressurized 

intertank unites the two propellant tanks. 

Liquid hydrogen (fuel) and liquid oxygen 

(oxidizer) are used as propellants for the 

shuttle’s three main engines. The external tank 

weighs 58,500 pounds empty and 

1,668,500 pounds when filled with propellants. 

The external tank is the “backbone” of the 

shuttle during launch, providing structural 

support for attachment with the solid rocket 

boosters and orbiter. It is the only component 

of the shuttle that is not reused. Approximately 

8.5 minutes after reaching orbit, with its 

propellant used, the tank is jettisoned and falls 

in a preplanned trajectory. Most of the tank 

disintegrates in the atmosphere, and the 

remainder falls into the ocean. 

The external tank is manufactured at NASA’s 

Michoud Assembly Facility in New Orleans by 

Lockheed Martin Space Systems. 

Foam Facts 

The external tank is covered with spray-on 

foam insulation that insulates the tank before 

and during launch. More than 90 percent of the 

tank’s foam is applied using an automated 

system, leaving less than 10 percent to be 

applied manually. 
MAY 2009 SHUTTLE REFERENCE DATA 101

There are two types of foam on the external 

tank, known as the Thermal Protection System, 

or TPS. One is low-density, closed-cell foam on 

the tank acreage and is known as Spray-OnFoam-Insulation, often referred to by its 

acronym, SOFI. Most of the tank is covered by 

either an automated or manually applied SOFI. 

Most areas around protuberances, such as 

brackets and structural elements, are applied by 

pouring foam ingredients into part-specific 

molds. The other is a denser composite 

material made of silicone resins and cork and 

called ablator. An ablator is a material that 

dissipates heat by eroding. It is used on areas 

of the external tank subjected to extreme heat, 

such as the aft dome near the engine exhaust, 

and remaining protuberances, such as the cable 

trays. These areas are exposed to extreme 

aerodynamic heating. 

Closed-cell foam used on the tank was 

developed to keep the propellants that fuel the 

shuttle’s three main engines at optimum 

temperature. It keeps the shuttle’s liquid 

hydrogen fuel at minus 423 degrees Fahrenheit 

and the liquid oxygen tank at near minus 

297 degrees Fahrenheit, even as the tank sits 

under the hot Florida sun. At the same time, 

the foam prevents a buildup of ice on the 

outside of the tank. 

The foam insulation must be durable enough to 

endure a 180-day stay at the launch pad, 

withstand temperatures up to 115 degrees 

Fahrenheit, humidity as high as 100 percent, 

and resist sand, salt, fog, rain, solar radiation 

and even fungus. Then, during launch, the 

foam must tolerate temperatures as high as 

2,200 degrees Fahrenheit generated by 

aerodynamic friction and radiant heating from 

the 3,000 degrees Fahrenheit main engine 

plumes. Finally, when the external tank begins 

reentry into the Earth’s atmosphere about 

30 minutes after launch, the foam maintains the 

tank’s structural temperatures and allows it to 

safely disintegrate over a remote ocean location. 

Though the foam insulation on the majority of 

the tank is only 1-inch thick, it adds 

4,823 pounds to the tank’s weight. In the areas 

of the tank subjected to the highest heating, 

insulation is somewhat thicker, between 1.5 to 

3 inches thick. Though the foam’s density 

varies with the type, an average density is 

about 2.4 pounds per cubic foot. 

Application of the foam, whether automated by 

computer or hand-sprayed, is designed to meet 

NASA’s requirements for finish, thickness, 

roughness, density, strength and adhesion. As 

in most assembly production situations, the 

foam is applied in specially designed, 

environmentally controlled spray cells and 

applied in several phases, often over a period of 

several weeks. Before spraying, the foam’s raw 

material and mechanical properties are tested 

to ensure they meet NASA specifications. 

Multiple visual inspections of all foam surfaces 

are performed after the spraying is complete. 

Most of the foam is applied at NASA’s 

Michoud Assembly Facility in New Orleans 

when the tank is manufactured, including most 

of the “closeout” areas, or final areas applied. 

These closeouts are done either by hand 

pouring or manual spraying. Additional 

closeouts are completed once the tank reaches 

Kennedy Space Center, Fla. 

The super lightweight external tank, or SLWT, 

made its first shuttle flight in June 1998 on 

mission STS-91. The SLWT is 7,500 pounds 

lighter than previously flown tanks. The SLWT 

is the same size as the previous design, but the 

liquid hydrogen tank and the liquid oxygen 

tank are made of aluminum lithium, a lighter, 
102 SHUTTLE REFERENCE DATA MAY 2009

stronger material than the metal alloy used 

previously. 

Beginning with the first Return to Flight 

mission, STS-114 in June 2005, several 

improvements were made to improve safety 

and flight reliability. 

Forward Bipod 

The external tank’s forward shuttle attach 

fitting, called the bipod, was redesigned to 

eliminate the large insulating foam ramps as a 

source of debris. Each external tank has two 

bipod fittings that connect the tank to the 

orbiter through the shuttle’s two forward 

attachment struts. Four rod heaters were 

placed below each forward bipod, replacing the 

large insulated foam Protuberance Airload, or 

PAL, ramps. 

Liquid Hydrogen Tank & Liquid Oxygen 

Intertank Flange Closeouts 

The liquid hydrogen tank flange located at the 

bottom of the intertank and the liquid oxygen 

tank flange located at the top of the intertank 

provide joining mechanisms with the intertank. 

After each of these three component tanks, 

liquid oxygen, intertank and liquid hydrogen, 

are joined mechanically, the flanges at both 

ends are insulated with foam. An enhanced 

closeout, or finishing, procedure was added to 

improve foam application to the stringer, or 

intertank ribbing, and to the upper and lower 

area of both the liquid hydrogen and liquid 

oxygen intertank flanges. 

Liquid Oxygen Feedline Bellows 

The liquid oxygen feedline bellows were 

reshaped to include a “drip lip” that allows 

condensate moisture to run off and prevent 

freezing. A strip heater was added to the 

forward bellow to further reduce the potential 

of high density ice or frost formation. Joints on 

the liquid oxygen feedline assembly allow the 

feedline to move during installation and during 

liquid hydrogen tank fill. Because it must flex, 

it cannot be insulated with foam like the 

remainder of the tank. 

Other tank improvements include: 

Liquid Oxygen & Liquid Hydrogen 

Protuberance Airload (PAL) Ramps 

External tank ET-119, which flew on the second 

Return to Flight mission, STS-121, in July 2006, 

was the first tank to fly without PAL ramps 

along portions of the liquid oxygen and 

liquid hydrogen tanks. These PAL ramps were 

extensively studied and determined to not be 

necessary for their original purpose, which was 

to protect cable trays from aeroelastic instability 

during ascent. Extensive tests were conducted 

to verify the shuttle could fly safely without 

these particular PAL ramps. Extensions were 

added to the ice frost ramps for the pressline 

and cable tray brackets, where these PAL ramps 

were removed to make the geometry of the 

ramps consistent with other locations on 

the tank and thereby provide consistent 

aerodynamic flow. Nine extensions were 

added, six on the liquid hydrogen tank and 

three on the liquid oxygen tank. 

Engine Cutoff (ECO) Sensor Modification 

Beginning with STS-122, ET-125, which 

launched on Feb. 7, 2008, the ECO sensor 

system feed through connector on the liquid 

hydrogen tank was modified by soldering the 

connector’s pins and sockets to address false 

readings in the system. All subsequent tanks 

after ET-125 have the same modification. 
MAY 2009 SHUTTLE REFERENCE DATA 103

Liquid Hydrogen Tank Ice Frost Ramps 

ET-128, which flew on the STS-124 shuttle 

mission, May 31, 2008, was the first tank to fly 

with redesigned liquid hydrogen tank ice frost 

ramps. Design changes were incorporated at 

all 17 ice frost ramp locations on the liquid 

hydrogen tank, stations 1151 through 2057, to 

reduce foam loss. Although the redesigned 

ramps appear identical to the previous design, 

several changes were made. PDL* and NCFI 

foam have been replaced with BX* manual 

spray foam in the ramp’s base cutout to reduce 

debonding and cracking; Pressline and cable 

tray bracket feet corners have been rounded to 

reduce stresses; shear pin holes have been 

sealed to reduce leak paths; isolators were 

primed to promote adhesion; isolator corners 

were rounded to help reduce thermal 

protection system foam stresses; BX manual 

spray was applied in bracket pockets to reduce 

geometric voids. 

*BX is a type of foam used on the tank’s 

“loseout,” or final finished areas; it is applied 

manually or hand-sprayed. PDL is an acronym 

for Product Development Laboratory, the first 

supplier of the foam during the early days of 

the external tank’s development. PDL is 

applied by pouring foam ingredients into a 

mold. NCFI foam is used on the aft dome, or 

bottom, of the liquid hydrogen tank. 

Liquid Oxygen Feedline Brackets 

ET-128 also was the first tank to fly with 

redesigned liquid oxygen feedline brackets. 

Titanium brackets, much less thermally 

conductive than aluminum, replaced aluminum 

brackets at four locations, XT 1129, XT 1377, 

Xt 1624 and Xt 1871. This change minimizes ice 

formation in under-insulated areas, and 

reduces the amount of foam required to cover 

the brackets and the propensity for ice 

development. Zero-gap/slip plane Teflon 

material was added to the upper outboard 

monoball attachment to eliminate ice adhesion. 

Additional foam has been added to the liquid 

oxygen feedline to further minimize ice 

formation along the length of the feedline. 
104 SHUTTLE REFERENCE DATA MAY 2009

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MAY 2009 LAUNCH & LANDING 105

LAUNCH AND LANDING 

LAUNCH 

As with all previous space shuttle launches, 

Atlantis has several options to abort its ascent if 

needed after engine failures or other systems 

problems. Shuttle launch abort philosophy is 

intended to facilitate safe recovery of the flight 

crew and intact recovery of the orbiter and its 

payload. 

Abort modes include: 

ABORT-TO-ORBIT 

This mode is used if there's a partial loss of 

main engine thrust late enough to permit 

reaching a minimal 105 by 85 nautical mile orbit 

with the orbital maneuvering system engines. 

The engines boost the shuttle to a safe orbital 

altitude when it is impossible to reach the 

planned orbital altitude. 

TRANSATLANTIC ABORT LANDING 

The loss of one or more main engines midway 

through powered flight would force a landing 

at either Zaragoza, Spain; Moron, Spain; or 

Istres, France. For launch to proceed, weather 

conditions must be acceptable at one of these 

TAL sites. 

RETURN-TO-LAUNCH-SITE 

If one or more engines shuts down early and 

there's not enough energy to reach Zaragoza, 

the shuttle would pitch around toward 

Kennedy until within gliding distance of the 

Shuttle Landing Facility. For launch to 

proceed, weather conditions must be forecast to 

be acceptable for a possible RTLS landing at 

KSC about 20 minutes after liftoff. 

ABORT ONCE AROUND 

An Abort Once Around (AOA) is selected if the 

vehicle cannot achieve a viable orbit or will not 

have enough propellant to perform a deorbit 

burn, but has enough energy to circle the Earth 

once and land about 90 minutes after liftoff. 

LANDING 

The primary landing site for Atlantis on 

STS‐125 is the Kennedy Space Center’s Shuttle 

Landing Facility. Alternate landing sites that 

could be used if needed because of weather 

conditions or systems failures are at Edwards 

Air Force Base, Calif., and White Sands Space 

Harbor, N.M. 
106 LAUNCH & LANDING MAY 2009

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MAY 2009 ACRONYMS/ABBREVIATIONS 107

A/D Analog-to-Digital 

ac Alternating Current 

ACP Astronaut Control Panel 

ACS Advanced Camera for Surveys 

ACTR 5 Actuator 5 

AFD Aft Flight Deck 

AID Analog Input Differential 

AKA Active Keel Actuator 

ALC Automatic Light Control 

AMSB Advanced Mechanism Selection Box 

APE Auxiliary PFR Extender 

ASIPE Axial Science Instrument Protective Enclosure 

ASLR Aft Shroud Latch Repair 

ATM Auxiliary Transport Module 

BAPS Berthing and Positioning System 

BAR Berthing Assist and Restraint 

BITE Built-In Test Equipment 

BOT Beginning of Travel 

BSP BAPS Support Post 

BSR BITE Status Register 

BTU Bus Terminal Unit 

CAB Cabin 

CASH Cross Aft Shroud Harness 

CAT Crew Aids and Tools 

CCTV Closed Circuit Television 

CDU Common Drive Unit 

CEP Containment Environmental Package 

CNTL Control 

COPE Contingency ORU Protective Enclosure 

COS Cosmic Origins Spectrograph 

CPC Cyro Port Cover 

CPT Comprehensive Performance Test 

CPUA Clamp Pickup Assembly 

CRES Corrosion-Resistant Steel 

CSM Cargo Systems Manual 

CSS Center Support Structure 

ACRONYMS AND ABBREVIATIONS 
108 ACRONYMS/ABBREVIATIONS MAY 2009

D/R Deploy/Return 

DBA Diode Box Assembly 

DBC Diode Box Controller 

Data Bus Coupler 

dc Direct Current 

DI/DO Discrete Input/Discrete Output 

DIH Discrete Input High 

DIL Discrete Input Low 

DOF Degree of Freedom 

DOH Discrete Output High 

DOL Discrete Output Low 

DPC Direct Power Converter 

DPST Double Pole, Single throw 

ECU Electronic Control Unit 

EGSE Electrical Ground Support Equipment 

EMU Extravehicular Mobility Unit 

ENA Enable 

EOT End of Travel 

EPDSU Enhanced Power Distribution and Switching Unit 

EPDU Electrical Power Distribution Unit 

ESM Electronic Support Module 

ESS Essential 

ET External Tank 

EURM Emergency Umbilical Retract Mechanism 

EVA Extravehicular Activity 

EXT External 

FD Flight Day 

FDA Failure Detection/Annunciation 

FGS Fine Guidance Sensor 

FHST Fixed Head Star Tracker 

FMDM Flexible Multiplexer/Demultiplexer 

FOC Faint Object Camera 

FSS Flight Support System 

FWD Forward 

FXC Forward X-Constraint 

GPC General Purpose Computer 

GSE Ground Support Equipment 

GSFC Goddard Space Flight Center 
MAY 2009 ACRONYMS/ABBREVIATIONS 109

HOST Hubble-On-Orbit Space Test 

HPGSCA HST Payload General Support Computer Assembly 

HRD Harness Restraint Device 

HST Hubble Space Telescope 

HTR Heater 

I/F Interface 

I/O Input/Output 

ICD Interface Control Document 

IND indicator 

IOM Input/Output Module 

IPCU Interface Power Control Unit 

IVA Intravehicular Activity 

J-BOX Junction Box 

JSC Johnson Space Center 

L/A Latch Assist 

LAT Latch 

LIS Load Isolation System 

LOPE Large ORU Protective Enclosure 

LPS Light and Particle Shield 

LRU Line Replaceable Unit 

MCA Motor Control Assembly 

MCC Mission Control Center 

MDI Magnetically Damped Isolator 

MDM Multiplexer/Demultiplexer 

MET Mission Elapsed Time 

MGSE Mechanical Ground Support Equipment 

MIA Multiplexer Interface Adapter 

MLI Multilayer Insulation 

MMC Mid-Motor Controller 

MMCA Mid-Motor Control Assembly 

MNA Main A 

MNB Main B 

MOD Mission Operations Directorate 

MOPE Multi-Mission ORU Protective Enclosure 

MSID Measurement Stimulus Identification 

M-STRUT Magnetic Strut 

MULE Multi-Use Lightweight Equipment 

NBL Neutral Buoyancy Lab 

NCC NICMOS CryoCooler 
110 ACRONYMS/ABBREVIATIONS MAY 2009

NCS NICMOS Cooling System 

NICMOS Near Infrared Camera and Multi-Object Spectrometer 

NOBL New Outer Blanket Layer 

NRZ-L Non-Return-to-Zero Level 

NT NOBL Transporter 

OPA ORU Plate Assembly 

ORB Orbiter 

ORU Orbital Replacement Unit 

ORUC Orbital Replacement Unit Carrier 

PA Pallet Assembly 

PBM Payload Bay Mechanical 

PCM Pulse-Code Modulation 

PCN Page Change Notice 

PCU Power Control Unit 

Power Conditioning Unit 

PDI Payload Data Interleaver 

PDIP Payload Data Interface Panel 

PDRS Payload Deployment and Retrieval System 

PDSU Power Distribution and Switching Unit 

PE Protective Enclosure 

PFR Portable Foot Restraint 

PGT Pistol Grip Tool 

PI Payload Interrogator 

PL Payload 

PLB Payload Bay 

PLBD Payload Bay Door 

POH Pulse Output High 

PPCU Port Power Conditioning Unit 

PRB Preload Release Bracket 

PRCS Primary Reaction Control System 

PRLA Payload Retention Latch Actuator 

PROM Programmable Read-Only Memory 

PRT Power Ratchet Tool 

PSP Payload Signal Processor 

PWR Power 

RAC Rigid Array Carrier 

REL Released 

RF Radio Frequency 

RL Retention Latch 

RMS Remote Manipulator System 
MAY 2009 ACRONYMS/ABBREVIATIONS 111

RNS Relative Navigation System 

RSIPE Radial Science Instrument Protective Enclosure 

RSU Rate Sensing Unit 

RWA Reaction Wheel Assembly 

SA Solar Array 

SAC Second Axial Carrier 

SADA Solar Array Drive Adapter 

SADM Solar Array Drive Mechanism 

SAP SAC Adapter Plate 

SCM Soft Capture Mechanism 

SCRS Soft Capture and Rendezvous System 

SCU Sequence Control Unit 

SI Science Instrument 

SI C&DH Science Instrument Command and Data Handling 

SIP Standard Interface Panel 

SLIC Super Lightweight Interchangeable Carrier 

SLP SpaceLab Pallet 

SM Servicing Mission 

Systems Management 

SMEL Servicing Mission Equipment List 

SOPE Small ORU Protective Enclosure 

SORU Small Orbital Replaceable Unit 

SPCU Starboard Power Conditioning Unit 

SSE Space Support Equipment 

SSME Space Shuttle Main Engine 

SSP Standard Switch Panel 

SSPC Solid State Power Controller 

SSSH Space Shuttle Systems Handbook 

STBD Starboard 

STIS Space Telescope Imaging Spectrograph 

STOCC Space Telescope Operations Control Center 

STS Space Transportation System 

SURV Survival 

TA Translation Aid 

tb Talkback 

TM Transport Module 

TVAC Thermal Vacuum 

UA Umbilical Actuator 

UARS Upper Atmospheric Research Satellite 

UASE UARS Airborne Structure Equipment 
112 ACRONYMS/ABBREVIATIONS MAY 2009

UDM Umbilical Disconnect Mechanism 

UPS Under Pallet Storage 

USA United Space Alliance 

VCU Video Control Unit 

VIK Voltage Improvement Kit 

WFC Wide Field Camera 

WFPC Wide Field Planetary Camera 

WRKLT Worklight 
MAY 2009 MEDIA ASSISTANCE 113

MEDIA ASSISTANCE 

NASA TELEVISION TRANSMISSION 

NASA Television is carried on an MPEG‐2 

digital signal accessed via satellite AMC‐6, at 

72 degrees west longitude, transponder 17C, 

4040 MHz, vertical polarization. For those in 

Alaska or Hawaii, NASA Television will be 

seen on AMC‐7, at 137 degrees west longitude, 

transponder 18C, at 4060 MHz, horizontal 

polarization. In both instances, a Digital Video 

Broadcast, or DVB‐compliant Integrated 

Receiver Decoder, or IRD, with modulation of 

QPSK/DBV, data rate of 36.86 and FEC 3/4 will 

be needed for reception. The NASA Television 

schedule and links to streaming video are 

available at: 

http://www.nasa.gov/ntv

NASA TVʹs digital conversion will require 

members of the broadcast media to upgrade 

with an ʹaddressableʹ Integrated Receiver 

De‐coder, or IRD, to participate in live news 

events and interviews, media briefings and 

receive NASAʹs Video File news feeds on a 

dedicated Media Services channel. NASA 

mission coverage will air on a digital NASA 

Public Services ʺFree to Airʺ channel, for which 

only a basic IRD will be needed. 

Television Schedule 

A schedule of key in‐orbit events and media 

briefings during the mission will be detailed in 

a NASA TV schedule posted at the link above. 

The schedule will be updated as necessary and 

will also be available at: 

http://www.nasa.gov/multimedia/nasatv/

mission_schedule.html

Status Reports 

Status reports on launch countdown and 

mission progress, in‐orbit activities and landing 

operations will be posted at: 

http://www.nasa.gov/shuttle

This site also contains information on the crew 

and will be updated regularly with photos and 

video clips throughout the flight. 

More Internet Information 

Information on the ISS is available at: 

http://www.nasa.gov/station

Information on safety enhancements made 

since the Columbia accident is available at: 

http://www.nasa.gov/returntoflight/

system/index.html

Information on other current NASA activities is 

available at: 

http://www.nasa.gov

Resources for educators can be found at the 

following address: 

http://education.nasa.gov
114 MEDIA ASSISTANCE MAY 2009

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MAY 2009 PUBLIC AFFAIRS CONTACTS 115

PUBLIC AFFAIRS CONTACTS 

HEADQUARTERS 

WASHINGTON, DC 

Space Operations Mission Directorate 

Katherine Trinidad 

Public Affairs Officer 

Space Operations 

202-358-1100 

katherine.trinidad@nasa.gov

John Yembrick 

Public Affairs Officer 

Space Operations 

202-358-1100 

john.yembrick-1@nasa.gov

Mike Curie 

Public Affairs Officer 

Space Operations 

202-358-1100 

michael.curie@nasa.gov

Science Mission Directorate 

J.D. Harrington 

Public Affairs Officer 

202-358-5241 

202-262-7048 (cell) 

J.D.Harrington@nasa.gov

JOHNSON SPACE CENTER 

HOUSTON, TEXAS 

James Hartsfield 

News Chief 

281-483-5111 

james.a.hartsfield@nasa.gov

Kyle Herring 

Public Affairs Specialist 

Space Shuttle Program Office 

281-483-5111 

kyle.j.herring@nasa.gov

Rob Navias 

Program and Mission Operations Lead 

281-483-5111 

rob.navias-1@nasa.gov

Nicole Cloutier-Lemasters 

Public Affairs Specialist 

Astronauts 

281-483-5111 

nicole.cloutier-1@nasa.gov

Kelly Humphries 

Public Affairs Specialist 

International Space Station and Mission 

Operations Directorate 

281-483-5111 

kelly.o.humphries@nasa.gov
116 PUBLIC AFFAIRS CONTACTS MAY 2009

KENNEDY SPACE CENTER 

CAPE CANAVERAL, FLORIDA 

Allard Beutel 

News Chief 

321-867-2468 

allard.beutel@nasa.gov

Candrea Thomas 

Public Affairs Specialist 

Space Shuttle 

321-861-2468 

candrea.k.thomas@nasa.gov

George H. Diller 

Public Affairs Specialist 

HST Payload Operations 

321-867-2468 

george.h.diller@nasa.gov

GODDARD SPACE FLIGHT CENTER 

GREENBELT, MARYLAND 

Edward Campion 

News Chief/HST-SM4 Team Lead 

301-286-0697 

edward.s.campion@nasa.gov

Donald Savage 

Public Affairs Officer 

301-286-8982 

donald.l.savage@nasa.gov

Wade Sisler 

Executive Producer 

301-286-6256 

wade.e.sisler@nasa.gov

Susan M. Hendrix 

HST Public Affairs 

301-286-7745 

susan.m.hendrix@nasa.gov

MARSHALL SPACE FLIGHT CENTER 

HUNTSVILLE, ALABAMA 

Dom Amatore 

Public Affairs Manager 

256-544-0034 

dominic.a.amatore@nasa.gov

June Malone 

Public Affairs Specialist 

News Chief/Media Manager 

256-544-0034 

june.e.malone@nasa.gov

Steve Roy 

Public Affairs Specialist 

Space Shuttle Propulsion 

256-544-0034 

steven.e.roy@nasa.gov

STENNIS SPACE CENTER 

BAY ST. LOUIS, MISSISSIPPI 

Chris McGee 

News Chief 

228-688-3249 

christopher.mcgee@nasa.gov

Paul Foerman 

Public Affairs Officer 

228-688-1880 

paul.foerman-1@nasa.gov
MAY 2009 PUBLIC AFFAIRS CONTACTS 117

AMES RESEARCH CENTER 

MOFFETT FIELD, CALIFORNIA 

Mike Mewhinney 

News Chief 

650-604-3937 

michael.mewhinney@nasa.gov

Jonas Dino 

Public Affairs Specialist 

650-604-5612 

jonas.dino@nasa.gov

Rachel Prucey 

Public Affairs Specialist 

650-604-0643 

Rachel.L.Purcey@nasa.gov

DRYDEN FLIGHT RESEARCH CENTER 

EDWARDS, CALIFORNIA 

Kevin Rohrer 

Director, Public Affairs 

661-276-3595 

kevin.j.rohrer@nasa.gov

Alan Brown 

News Chief 

661-276-2665 

alan.brown@nasa.gov

Leslie Williams 

Public Affairs Specialist 

661-276-3893 

leslie.a.williams@nasa.gov

GLENN RESEARCH CENTER 

CLEVELAND, OHIO 

Lori Rachul 

News Chief 

216-433-8806 

lori.j.rachul@nasa.gov

Jeannette P. Owens 

Public Affairs Specialist 

216-433-2990 

jeannette.p.owens@nasa.gov

Katherine Martin 

Public Affairs Specialist 

216-433-2406 

katherine.martin@nasa.gov

LANGLEY RESEARCH CENTER 

HAMPTON, VIRGINIA 

Marny Skora 

Head, News Media Office 

757-864-3315 

marny.skora@nasa.gov

Keith Henry 

Public Affairs Officer 

757-864-6120 

h.k.henry@nasa.gov

Chris Rink 

Public Affairs Officer 

757-864-6786 

christopher.p.rink@nasa.gov

Kathy Barnstorff 

Public Affairs Officer 

757-864-9886 

katherine.a.barnstorff@nasa.gov
118 PUBLIC AFFAIRS CONTACTS MAY 2009

SPACE TELESCOPE SCIENCE 

INSTITUTE 

BALTIMORE, MARYLAND 

Ray Villard 

News Director 

Space Telescope Science Institute 

410-338-4514 

villard@stsci.edu

Cheryl Gundy 

Public Affairs Officer 

Space Telescope Science Institute 

410-338-4707 

gundy@stsci.edu

LOCKHEED-MARTIN SPACE SYSTEMS 

SUNNYVALE, CALIFORNIA 

Buddy Nelson 

Media Relations 

510-797-0349 

buddynelson@mac.com

LOCKHEED-MARTIN SPACE SYSTEMS 

MICHOUD ASSEMBLY FACILITY 

NEW ORLEANS, LOUSIANIA 

Marion A. LaNasa Jr. 

Director, Communications 

Michoud Operations 

504-257-1307 

marion.a.lanasa@maf.nasa.gov

BALL AEROSPACE 

BOULDER, COLORADO 

Roz Brown 

Media Relations Manager 

1600 Commerce St. 

Boulder, CO 80301 

303-533-6059 

rbrown@ball.com

Sarah Sloan 

Corporate Communications Manager 

1600 Commerce St. 

Boulder, CO 80301 

303-533-4945 

ssloan@ball.com

UNITED SPACE ALLIANCE 

Jessica Pieczonka 

Houston Operations 

281-212-6252 

832-205-0480 

jessica.b.pieczonka@usa-spaceops.com

Tracy Yates 

Florida Operations 

321-861-3956 

(c) 321-750-1739 

tracy.e.yates@usa-spaceops.com
MAY 2009 PUBLIC AFFAIRS CONTACTS 119

PRATT & WHITNEY ROCKETDYNE 

Bryan Kidder 

Communications Director 

Canoga Park, Calif. 

818-586-2213 office 

818-307-3830 cell 

bryan.kidder@pwr.utc.com

Carri Karuhn 

Media Relations – Canoga Park, Calif. 

818-586-4963 office 

818-307-2285 cell 

carri.karuhn@pwr.utc.com

Nancy Colaguori 

Media Relations – West Palm Beach, Fla. 

561-796-2219 office 

561-281-9734 cell 

nancy.colaguori@pwr.utc.com

ATK LAUNCH SYSTEMS 

George Torres 

Vice President, Communications – Salt Lake 

City, Utah 

801-251-2819 

801-699-2637 cell 

george.torres@atk.com

Jessica Rye 

Regional Communications, Senior Manager – 

Kennedy Space Center, Fla. 

321-328-2468 office 

jessica.rye@atk.com
120 PUBLIC AFFAIRS CONTACTS MAY 2009

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