yee@trident.arc.nasa.gov (Peter E. Yee) (02/28/89)
RELEASE: 89- IMMEDIATE
THIRD TRACKING AND DATA RELAY SATELLITE TO BE DEPLOYED BY STS-29
Deployment of the third Tracking and Data Relay Satellite
(TDRS-D) will highlight the 28th Space Shuttle mission (STS-
29). The assessed launch date is no earlier than March 10, 1989.
Three TDRS, operating from geosynchronous orbit, are
required to complete the constellation known as the Tracking and
Data Relay Satellite System (TDRSS). TDRSS will increase
communications, between Earth-orbiting spacecraft and a ground-
based tracking station, from 15 to 85 percent per orbit and
facilitate a much higher rate of data flow.
TDRS-C was successfully deployed on STS-26 in September 1988
and is located in geosynchronous orbit at 171 degrees W.
longitude, south of Hawaii. TDRS-D will be located at 41 degrees
W. longitude, east of Brazil. TDRS-A, deployed on STS-6 in April
1983, then will be moved to a parking orbit and used only if a
failure occurs with one of the remaining two satellites. TDRS-B
was lost in the 51-L Challenger accident.
Commander of the five-man crew is Michael L. Coats, captain,
USN. Coats was pilot of STS 41-D, the maiden flight of orbiter
Discovery. John E. Blaha, colonel, USAF, is pilot of the
mission. STS-29 will be his first space flight.
Rounding out the crew are three mission specialists: James
F. Buchli, colonel, USMC; Robert C. Springer, colonel, USMC; and
James P. Bagian, M.D. Buchli is making his third Shuttle flight
having flown as a mission specialist on STS 51-C, the first
Department of Defense Shuttle mission, and STS 61-A, the West
German Spacelab flight. Springer and Bagian are making their
first Shuttle flights.
Discovery, making its eighth flight, is assessed to be ready
for launch no earlier than 8:11 a.m. EST, March 10, from the
Kennedy Space Center, Fla., launch pad 39-B, into a 160 nautical
mile, 28.45 degree orbit. Nominal mission duration is 5 days, 1
hour, 7 minutes. Deorbit is planned on orbit 80, with landing
scheduled for 9:48 a.m. EST, March 15, at Edwards Air Force Base,
Calif. In the event of a slip in the launch, liftoff would occur
1 minute earlier for each day the launch is delayed.
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TDRS-D will be deployed 6 hours, 13 minutes into the mission
on flight day 1. Two additional deployment opportunities are
available on that day and one the following day.
An Air Force-developed inertial upper stage (IUS) will boost
the TDRS to geosynchronous orbit (22,300 miles above Earth) after
deployment from the Shuttle. The IUS is mated to the TDRS-D and
the combination spacecraft and upper stage will be spring ejected
from the payload bay of the orbiter.
Following deployment, Discovery will maneuver to a safe
position behind and above the TDRS-D/IUS before the first stage
of the two-stage IUS motor ignites about an hour after
deployment. The three-axis, stabilized upper stage will maneuver
TDRS to the desired attitude where it will be configured for
operation by the NASA White Sands Ground Terminal, N.M.
CONTEL, Atlanta, Ga., owns and operates the TDRSS for
NASA. TRW's Defense and Space Systems Group, Redondo Beach,
Calif., builds the satellites.
The Orbiter Experiments Program Autonomous Supporting
Instrumentation System (OASIS) will be flown again on STS-29 to
record environmental data in the orbiter payload bay during
flight phases. OASIS will measure TDRS vibration, strain,
acoustics and temperature during launch ascent using transducers
affixed directly to the payload.
OASIS flight hardware consists of signal conditioning,
multiplexing and recording equipment mounted on a Shuttle
adaptive payload carrier behind the TDRS. Command and status
interface is achieved through the standard mixed cargo harness
and the general purpose computers.
In addition to TDRS-D and OASIS, Discovery will carry the
Space Station Heat Pipe Advanced Radiator Element (SHARE) in the
payload bay. Several secondary payloads will be carried in the
middeck of Discovery, including the IMAX camera, two student
experiments, a protein crystal growth experiment and a chromosome
and plant cell division experiment.
After landing, Discovery will be towed to the NASA Ames-
Dryden Flight Research Facility, hoisted atop the Shuttle Carrier
Aircraft and ferried back to the Kennedy Space Center to begin
processing for its next flight scheduled for August.
(END OF GENERAL RELEASE, BACKGROUND INFORMATION FOLLOWS)
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GENERAL INFORMATION
NASA Select Television Transmission
The schedule for television transmission from the orbiter
and for the change-of-shift briefings from Johnson Space Center,
Houston, will be available during the mission at Kennedy Space
Center, Fla.; Marshall Space Flight Center, Huntsville, Ala.;
Johnson Space Center; and NASA Headquarters, Washington, D.C.
The television schedule will be updated daily to reflect changes
dictated by mission operations. NASA Select television is
available on RCA Satcom F-2R, Transponder 13, located at 72
degrees west longitude.
Special Note To Broadcasters
Beginning in February and continuing throughout the mission,
approximately 7 minutes of audio interview material with the crew
of STS-29 will be available to broadcasters by calling 202/269-
6572.
Status Reports
Status reports on countdown and mission progress, on-orbit
activities and landing operations will be produced by the
appropriate NASA newscenter.
Briefings
An STS-29 mission press briefing schedule will be issued
prior to launch. During the mission, flight control personnel
will be on 8-hour shifts. Change-of-shift briefings by the off-
going flight director will occur at approximately 8-hour
intervals.
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STS-29 QUICK LOOK
Assessed Launch Date: March 10, 1989
Launch Window: 8:11 a.m. - 10:41 a.m. EST
Launch Site: KSC, Pad 39B
Orbiter: Discovery (OV-103)
Altitude: 160 nm
Inclination: 28.45 degrees
Duration: 5 days, 1 hour, 7 minutes
Landing Date/Time: March 15, 1989, 9:48 a.m. EST
Primary Landing Site: Edwards AFB, Calif., Runway 17
Alternate Landing Sites:
Return to Launch Site - Kennedy Space Center, Runway 33
Transoceanic Abort Landing - Ben Guerir, Morocco
Abort Once Around - Edwards AFB, Calif.
Crew: Michael L. Coats, Commander
John E. Blaha, Pilot
James F. Buchli, Mission Specialist
Robert C. Springer, Mission Specialist
James P. Bagian, Mission Specialist
Primary Payload: Tracking & Data Relay Satellite (TDRS-D)
Secondary Payloads:
Space Station Heat Pipe Advanced Radiator Element (SHARE)
Chromosomes & Plant Cell Division (CHROMEX)
Protein Crystal Growth (PCG)
Shuttle Student Involvement Program (SSIP) - 2 experiments
Orbiter Experiments - Autonomous Supporting Instrumentation
System (OASIS)
IMAX Camera
STS-29 MISSION OBJECTIVES
The primary objective of this flight is to successfully
deploy the Tracking and Data Relay Satellite-D/Inertial Upper
Stage (TDRS-D/IUS). TDRS-D is scheduled to be deployed on flight
day 1, orbit 6. Several backup deployment opportunities exist
during the flight. Secondary objectives are to perform all
operations necessary to support the requirements of the middeck
and payload bay experiments.
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LAUNCH PREPARATIONS, COUNTDOWN AND LIFTOFF
After the successful STS-26 mission, Discovery was returned
to KSC from Dryden Flight Research Facility on Oct. 8. The next
day, Discovery was towed to the processing hangar for post-flight
deconfiguration and inspections.
As planned, the three main engines were removed in October
and taken to the main engine shop in the Vehicle Assembly
Building for the replacement of several components. During post-
flight inspections, technicians discovered a small leak in the
cooling system of the main combustion chamber of the number one
main engine. That engine was shipped back to the vendor where
repairs could be made and a new engine was shipped from the
Stennis Space Center, Miss.
Discovery's three main engines were installed before the end
of last year. Engine 2031 is installed in the number one
position, engine 2022 is in the number two position and engine
2028 is in the number three position.
The right hand orbital maneuvering system pod was removed in
late October and transferred to the Hypergolic Maintenance
Facility where a small internal leak was repaired. One of the
orbiter's cooling systems, called the flash evaporator system,
was replaced after some in-flight problems. Post-flight
inspections revealed that the system was clogged with foreign
material.
Once the turn-around activities were completed, Discovery
was transferred from the Orbiter Processing Facility to the
Vehicle Assembly Building on Jan. 19.
Solid rocket motor (SRM) segments began arriving at KSC in
September, and the first segment - the left aft booster - was
stacked on Mobile Launcher 2 in VAB high bay 1 on Oct. 21.
Booster stacking operations were completed by early December and
the external tank was mated to the two boosters on Dec. 16.
The OASIS payload was installed in Discovery's payload bay
for flight on Dec. 9. Flight crew members came to KSC to perform
the Crew Equipment Interface Test on Dec. 11 to become familiar
with Discovery's crew compartment and equipment associated with
the mission.
The Tracking and Data Relay Satellite (TDRS-D) arrived at
the Vertical Processing Facility (VPF) on Nov. 30, and its
Inertial Upper Stage (IUS) arrived Dec. 27. The TDRS/IUS were
joined together on Dec. 29 and all integrated testing was
performed the first week of January. As part of those tests,
Astronauts James Bagian and Robert Springer participated in the
mission sequence test to verify payload functions that occur
post-launch and during deployment.
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A variety of middeck payloads and experiments, some of which
are time critical and installed during the launch countdown, are
processed through various KSC facilities.
Discovery was moved from the OPF to the VAB on Jan. 23,
where it was mated to the external tank and SRBs. A Shuttle
Interface Test was conducted to check the mechanical and
electrical connections between the various elements of the
Shuttle vehicle and onboard flight systems.
The assembled Space Shuttle vehicle was rolled out of the
VAB aboard its mobile launcher platform for the 4.2 mile trip to
Launch Pad 39-B on Feb. 3. TDRS-D and its IUS upper stage were
transferred from the VPF to Launch Pad 39-B on Jan. 17. The
payload was installed into Discovery's payload bay on Feb. 6.
A countdown demonstration test, a dress rehearsal for the
STS-29 flight crew and KSC launch team and a practice countdown
for the launch, was completed on Feb. 7.
Launch preparations scheduled the last 2 weeks prior to
launch countdown include change-out of the orbiter SSME liquid
oxygen pumps; final vehicle ordnance activities, such as power-
on, stray-voltage checks and resistance checks of firing
circuits; loading the fuel cell storage tanks; pressurizing the
hypergolic propellant tanks aboard the vehicle; final payload
closeouts; and a final functional check of the range safety and
SRB ignition, safe and arm devices.
The launch countdown is scheduled to pick up at the T-
minus-43-hour mark, leading up to the first Shuttle liftoff for
the year. The STS-29 launch will be conducted by a joint
NASA/industry team from Firing Room 1 in the Launch Control
Center.
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MAJOR COUNTDOWN MILESTONES
COUNT EVENT
T-43 Hours Power up the Space Shuttle vehicle.
T-34 Hours Begin orbiter and ground support
equipment closeouts for launch.
T-30 Hours Activate orbiter's navigation aids.
T-27 Hours (holding) Enter first built-in hold for 8 hrs.
T-27 Hours (counting) Begin preparations for loading fuel
cell storage tanks with liquid
oxygen and liquid hydrogen
T-25 Hours Load fuel cell liquid oxygen
T-22 Hours, 30 minutes Load fuel cell liquid hydrogen.
T-22 Hours Perform interface check between
Mission Control and Merritt Island
Launch Area (MILA) tracking station.
T-20 Hours Activate and warm up inertial
measurement units (IMUs).
T-19 Hours Enter the 8-hour, built-in hold.
Activate orbiter comm system.
T-11 Hours (holding) Start 18-hour, 10-minute, built-in
hold. Check ascent switch list on
orbiter flight and middecks.
T-11 Hours (counting) Retract Rotating Service Structure.
T-9 Hours Activate orbiter's fuel cells.
T-8 Hours Configure Mission Control
communications for launch. Start
clearing blast danger area.
T-6 Hours, 30 minutes Perform Eastern Test Range open loop
command test.
T-6 Hours Enter 1-hour built-in hold.
T-6 Hours (counting) Start external tank chilldown and
propellant loading.
T-5 Hours Start IMU pre-flight calibration.
T-4 Hours Perform MILA antenna alignment.
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T-3 Hours Begin 2-hour built-in hold. Loading
external tank completed and tank in
stable replenishment mode. Ice team
to pad for inspections. Closeout
crew to white room to begin preping
orbiter's cabin for flight crew
entry. Wake flight crew (launch
minus 4 hours, 55 minutes).
T-3 Hours (counting) Resume countdown.
T-2 Hours, 55 minutes Flight crew departs O&C Building for
39-B (Launch minus 3 hours, 15
minutes).
T-2 Hours, 30 minutes Crew enters orbiter vehicle (Launch
minus 2 Hours, 50 minutes).
T-60 minutes Start pre-flight alignment of IMUs.
T-20 minutes (holding) 10-minute, built-in hold begins.
T-20 minutes (counting) Configure orbiter computers for
launch.
T-10 minutes White room closeout crew cleared
through area roadblocks.
T-9 minutes (holding) 10-minute, built-in hold begins.
Perform status check and receive
Mission Management Team "go."
T-9 minutes (counting) Start ground launch sequencer.
T-7 minutes, 30 seconds Retract orbiter access arm.
T-5 minutes Start auxiliary power units. Arm
range safety, SRB ignition systems.
T-3 minutes, 30 seconds Orbiter goes on internal power.
T-2 minutes, 55 seconds Pressurize liquid oxygen tank and
retract gaseous oxygen vent hood.
T-1 minute, 57 seconds Pressurize liquid hydrogen tank.
T-31 seconds "Go" from ground computer for
orbiter computers to start the
automatic launch sequence.
T-28 seconds Start SRB hydraulic power units.
T-21 seconds Start SRB gimbal profile test.
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T-6.6 seconds Main engine start.
T-3 seconds Main engines at 90 percent thrust.
T-0 SRB ignition, holddown-post release
and liftoff.
T+7 seconds Shuttle clears launch tower and
control switches to Houston.
STS-29 TRAJECTORY SEQUENCE OF EVENTS
_________________________________________________________________
RELATIVE
EVENT MET VELOCITY MACH ALTITUDE
(d:h:m:s) (fps) (ft)
_________________________________________________________________
Launch 0:00:00:00
Begin Roll Maneuver 0:00:00:09 157 .14 593
End Roll Maneuver 0:00:00:17 356 .32 2,749
SSME Throttle Down to 65% 0:00:00:28 652 .58 7,588
Max. Dyn. Pressure (Max Q) 0:00:00:52 1,173 1.08 26,089
SSME Throttle Up to 104% 0:00:00:57 1,274 1.20 30,768
SRB Staging 0:00:02:06 4,169 3.77 155,892
Negative Return 0:00:03:58 6,862 7.09 327,981
Main Engine Cutoff (MECO)* 0:00:08:32 24,507 22.70 363,209
Zero Thrust 0:00:08:39
OMS 2 Burn** 0:00:39:53
TDRS/IUS Deploy (orbit 5) 0:06:13:00
Deorbit Burn (orbit 80) 5:00:06:00
Landing (orbit 81) 5:01:07:00
* Apogee, Perigee at MECO: 156 x 35
** Direct insertion ascent: No OMS 1 required
Apogee, Perigee post-OMS 2: 160 x 160
Apogee, Perigee post-deploy: 177 x 161
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SPACE SHUTTLE ABORT MODES
Space Shuttle launch abort philosophy aims toward safe and
intact recovery of flight crew, orbiter and payload. Modes are:
* Abort-To-Orbit (ATO) -- Partial loss of main engine thrust
late enough to permit reaching a minimal 105-nm orbit with
orbital maneuvering system engines.
* Abort-Once-Around (AOA) -- Earlier main engine shutdown
with the capability to allow one orbit around before landing at
Edwards AFB, Calif.; White Sands Space Harbor (Northrup Strip),
N.M.; or the Shuttle Landing Facility (SLF) at KSC, Fla.
* Trans-Atlantic Abort Landing (TAL) -- Loss of two main
engines midway through powered flight would force a landing at
Ben Guerir, Morocco; Moron, Spain; or Banjul, The Gambia.
* Return-To-Launch-Site (RTLS) -- Early shutdown of one or
more engines and without enough energy to reach Ben Guerir, would
result in a pitch around and thrust back toward KSC until within
gliding distance of the SLF.
STS-29 contingency landing sites are Edwards AFB, White
Sands, Kennedy Space Center, Ben Guerir, Moron and Banjul.
SUMMARY OF MAJOR FLIGHT ACTIVITIES
DAY ONE
Ascent, Post-insertion checkout
Pre-deploy checkout, TDRS-D/IUS deploy; PCG activation, SSIP
DAY TWO
TDRS-D/IUS backup deploy opportunity
AMOS, CHROMEX, IMAX, PCG, SSIP, SHARE test 1
DAY THREE
AMOS, CHROMEX, IMAX, PCG, SSIP, SHARE test 2
DAY FOUR
AMOS, CHROMEX, SSIP
DAY FIVE
Flight control systems checkout, Cabin stowage, Landing preps
CHROMEX, SSIP; PCG deactivation, SHARE deprime
DAY SIX
SHARE cold soak test, SSIP
Deorbit preparation, Deorbit burn, Landing at EAFB
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LANDING AND POST-LANDING ACTIVITIES
KSC is responsible for ground operations of the orbiter once
it has rolled to a stop on the runway at Edwards AFB. Operations
include preparing the Shuttle for the return trip to Kennedy.
After landing, the flight crew aboard Discovery begins
"safing" vehicle systems. Immediately after wheelstop, specially
garbed technicians will first determine that any residual
hazardous vapors are below significant levels for other safing
operations to proceed.
A mobile white room is moved into place around the crew
hatch once it is verified that there are no concentrations of
toxic gases around the forward part of the vehicle. The crew is
expected to leave Discovery about 45 to 50 minutes after
landing. As the crew exits, technicians enter the orbiter to
complete the vehicle safing activity.
Once the initial aft safety assessment is made, access
vehicles are positioned around the rear of the orbiter so that
lines from the ground purge and cooling vehicles can be connected
to the umbilical panels on the aft end of Discovery.
Freon line connections are completed and coolant begins
circulating through the umbilicals to aid in heat rejection and
protect the orbiter's electronic equipment. Other lines provide
cooled, humidified air to the payload bay and other cavities to
remove any residual fumes and provide a safe environment inside
Discovery.
A tractor will be connected to Discovery and the vehicle
will be towed off the runway at Edwards and positioned inside the
Mate/Demate Device at the nearby Ames-Dryden Flight Research
Facility. After the Shuttle has been jacked and leveled,
residual fuel cell cryogenics are drained and unused pyrotechnic
devices are disconnected.
The aerodynamic tail cone is installed over the three main
engines, and the orbiter is bolted on top of the 747 Shuttle
Carrier Aircraft for the ferry flight back to Florida. A
refueling stop is necessary to complete the journey.
Once back at Kennedy, Discovery will be pulled inside the
hangar-like facility for post-flight inspections and in-flight
anomaly troubleshooting. These operations are conducted in
parallel with the start of routine systems reverification to
prepare Discovery for its next mission.
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TRACKING AND DATA RELAY SATELLITE SYSTEM
The Tracking and Data Relay Satellite, TDRS-D, is the fourth
TDRS communications spacecraft to be launched aboard the Space
Shuttle and completes the constellation of on-orbit satellites
for NASA's advanced space communications system. TDRS-1 was
launched during Challenger's maiden flight in April 1983. The
second was lost during the Challenger accident in January 1986.
TDRS-3 was launched successfully on Sept. 29, 1988, during the
landmark mission of Discovery, which returned the Space Shuttle
to flight.
TDRS-1 is in geosynchronous orbit over the Atlantic Ocean,
just east of Brazil (41 degrees west longitude at the equator).
When it was launched, it failed to reach its desired orbit
because of a failure in the upper-stage booster rocket. A NASA-
industry team subsequently conducted a series of delicate
spacecraft maneuvers, using on-board thrusters, to place TDRS-1
into the desired 22,300-mile-altitude orbit.
TDRS-3 is in geosynchronous orbit over the Pacific Ocean,
south of Hawaii (171 degree west longitude, also over the
equator). It has performed flawlessly in tests and helped
support the STS-27 mission in December 1988.
After its launch, TDRS-D will be designated TDRS-4.
Following its arrival at geosynchronous orbit and a series of
tests, it will replace the partially degraded TDRS-1 over the
Atlantic. TDRS-1 then will be moved to 79 degrees west
longitude, above the Equator, where it will be used as an on-
orbit spare.
The two operational TDRS -- those located at 41 and 171
degrees west longitude -- will support up to 23 user spacecraft
simultaneously and provide two basic types of service: a
multiple-access service that simultaneously relays data from as
many as 19 low-data-rate user spacecraft; and a single-access
service that provides two high-data-rate communications relays
from each satellite.
TDRS-4 will be deployed from the orbiter about 6 hours after
launch. The solid-propellant Boeing/U.S. Air Force Inertial
Upper Stage (IUS) will transfer the satellite to geosynchronous
orbit. IUS separation will occur about 13 hours after launch.
The concept of using advanced communications satellites was
developed in the early 1970s, following studies showing that a
system of communications satellites operated from a single ground
terminal could support Space Shuttle and other low-Earth-orbit
space missions more effectively than a worldwide network of
ground stations. The current ground station network can only
provide support for a small fraction -- typically 15 to 20
percent -- of the orbits of user spacecraft. The modern, space-
based TDRS network covers at least 85 percent of the orbits.
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The new system also will facilitate a much higher
information flow rate between the spacecraft and the ground.
This will be particularly important as NASA resumes regular
Shuttle flights and launches satellites with high data rates.
NASA's Space Tracking and Data Network ground stations,
managed by the Goddard Space Flight Center, Greenbelt, Md., will
be reduced significantly in number. Three of the network's
present ground stations -- Madrid, Spain; Canberra, Australia;
and Goldstone, Calif. -- already have been transferred to the
Deep Space Network, managed by the Jet Propulsion Laboratory,
Pasadena, Calif. The remaining ground stations, except those
needed for launch operations, will be closed or transferred to
other agencies.
The White Sands Ground Terminal (WSGT) is situated on a NASA
test site located between Las Cruces and White Sands, N.M. A
colocated NASA facility provides the interface between the WSGT
and the NASA space network facilities at Goddard Space Flight
Center. A technologically advanced second ground terminal is
being built near White Sands to provide back-up and additional
capability.
The tracking and data relay satellites are the largest
privately owned telecommunications spacecraft ever built, and the
first to handle satellite communications through the S and Ku
frequency bands. Each weighs about 2 tons, spans almost 60 feet
across its solar panels and contains seven antennas. Each of the
two gold-plated, single-access antennas measures 16 feet in
diameter and, when fully deployed, spans more than 42 feet from
tip to tip.
The combination of satellites and ground facilities is
referred to as the Tracking and Data Relay Satellite System or
TDRSS. NASA leases the TDRSS complement of services from CONTEL,
Atlanta, Ga., which is the owner, operator and prime
contractor. CONTEL's two primary subcontractors are TRW's Space
and Technology Group, Redondo Beach, Calif., and the Harris
Corporation's Government Communications Systems Division,
Melbourne, Fla. TRW designed and built the spacecraft and
software for ground terminal operation, and integrated and tested
the system. Harris designed and built the ground terminal
equipment.
The Space Shuttle, LANDSAT Earth Resources satellites, Solar
Mesosphere Explorer, Earth Radiation Budget Satellite, Solar
Maximum Mission satellite and Spacelab have been primary users of
TDRSS. They will be joined in the future by the Hubble Space
Telescope, Gamma Ray Observatory, Upper Atmosphere Research
Satellite and others.
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INERTIAL UPPER STAGE
The Interial Upper Stage (IUS) will be used to place NASA's
TDRS-D into geosynchronous orbit during the STS-29 Space Shuttle
mission.
The STS-29 crew will deploy the combined IUS/TDRS-D payload
approximately 6 hours, 13 minutes after liftoff, in a low-Earth
orbit of 160 nautical miles. Upper stage airborne support
equipment, located in the orbiter payload bay, positions the
combined IUS/TDRS-D into its proper deployment attitude -- an
angle of 52 degrees -- and ejects it into low-Earth orbit.
Deployment from the orbiter will be by a spring-ejection system.
Following deployment, the orbiter will move away from the
IUS/TDRS-D to a safe distance. The IUS first stage will fire
about 1 hour after deployment. After the first stage burn of 146
seconds, the solid fuel motor will shut down. After coasting for
about 5 hours, 13 minutes, the first stage will separate and the
second stage motor will ignite at 6 hours, 12 minutes after
deployment to place the spacecraft in its desired orbit.
Following a 108-second burn, the second stage will shut down as
the IUS/TDRS-D reaches the predetermined, geosynchronous orbital
position.
Thirteen hours, 9 minutes after liftoff, the second stage
will separate from TDRS-D and perform an anti-collision maneuver
with its onboard reaction control system.
The IUS has a number of features which distinguish it from
previous upper stages. It has the first completely redundant
avionics system developed for an unmanned space vehicle. It can
correct in-flight features within milliseconds.
Other advanced features include a carbon composite nozzle
throat that makes possible the high-temperature, long-duration
firing of the IUS motors and a redundant computer system.
The IUS is 17 ft. long, 9 ft. in diameter and weighs more
than 32,500 lb., including 27,400 lb. of solid fuel propellant.
The IUS consists of an aft skirt, an aft stage containing 21,400
lb. of solid propellant which generates approximately 42,000 lb.
of thrust, an interstage, a forward stage containing 6,000 lb. of
propellant generating 18,000 lb. of thrust, and an equipment
support section. The equipment support section contains the
avionics which provide guidance, navigation, telemetry, command
and data management, reaction control and electrical power.
The IUS is built by Boeing Aerospace, Seattle, under
contract to the U.S. Air Force Systems Command. Marshall Space
Flight Center, Huntsville, Ala., is NASA's lead center for IUS
development and program management of NASA-configured IUSs
procured from the Air Force.
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SECONDARY PAYLOADS
SPACE STATION HEAT PIPE ADVANCED RADIATOR ELEMENT (SHARE)
SHARE flight experiment will be mounted on the starboard
sill of the Orbiter's payload bay with a small instrumentation
package mounted in the forward payload bay. The goal of the
experiment is to test a first-of-its-kind method for a potential
cooling system of Space Station Freedom.
The heat pipe method uses no moving parts and works through
the convection currents of ammonia. Three electric heaters will
warm one end of the 51-foot long SHARE. The heaters turn liquid
ammonia into vapor which transports the heat through the length
of the pipe, where a foot-wide aluminum fin radiates it into
space. The fin is cooled by the space environment, and the
ammonia is inturn condensed and recirculated.
Two small pipes run through the center of the radiator down
its length, branching out like the tines of a fork at the end
which receives heat, called the evaporator. The top pipe holds
the vaporized ammonia; the bottom holds liquid ammonia. In the
evaporator portion, a fine wire mesh wick, which works along the
same principal as the wick of an oil lamp, pulls the liquid
ammonia from one pipe to the other, where it vaporizes. Small
grooves allow the condensed ammonia to drop back to the bottom
pipe.
The radiator for SHARE weighs about 135 pounds, but with its
support pedestals, support beam, heaters and instrumentation
package, the total experiment weighs about 650 pounds.
Crew members will switch the heaters on using controls
located on the aft flight deck. Each of the experiment's two
500-watt heaters and single 1,000-watt heater is controlled
individually and will be switched on in turn, applying heat that
will increase steadily in 500-watt increments up to a maximum of
2,000 watts.
The experiment will be activated for two complete orbits in
two different attitudes, the first with the payload bay toward
Earth and the second with the orbiter's tail toward the Sun. The
heaters will go through a complete 500-watt to 2,000-watt cycle
for each activation. This will simulate the heat that needs to
be dissipated from the Space Station, and the two attitudes will
provide data on the heat pipe's operation in different thermal
environments.
Other information also may be obtained during STS-29 if time
permits, including a test of the heat pipe's minimum operating
temperature, thought to be about minus 20 degrees Fahrenheit, and
a test of its ability to recover from acceleration.
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The crew may fire the orbiter's aft reaction control system
thrusters for about 6 seconds, an action that would push the
fluid in SHARE to one end of the pipe. The heaters then may be
turned on again to see if the heat pipe will automatically
reprime itself and begin operating.
CHROMEX
This experiment will determine whether the roots of a plant
in microgravity will develop similarly to those on Earth. Root-
free shoots of the plants daylily and haplopappus will be used.
The experiment will determine whether:
o The normal rate, frequency and patterning of cell division
in the root tops can be sustained in space.
o The chromosomes and genetic makeup is maintained during
and after exposure to space flight conditions.
o Aseptically grown tissue cultured materials will grow and
differentiate normally in space
The criteria for comparison include: number of roots
formed, length, weight and quality based on subjective appraisal
as well as quantitative morphological and histological
examination.
Root tip cells will be analyzed for their karyotype, the
configuration of chromosomes, upon return. Haplopappus
dicatolydon is a unique flowering plant with four chromosomes in
its diploid cells (2n=4). Daylily monocatolydon also has
specific features of its karyotype 2n=22.
Daylily and haplopappus gracilis will be flown in the plant
growth unit (PGU), located in the orbiter middeck. The PGU can
hold up to six plant growth chambers (PGC). One PGC will be
replaced with the atmospheric exchange system that will filter
cabin air before pumping through the remaining PGCs. The
experimental plan is to collect and treat roots post flight,
before the first cell division cycle is completed.
Previous observations of some plants grown in space have
indicated a substantially lowered level of cell division in
primary root tips and a range of chromosomal abnormalities, such
as breakage and fusion.
PROTEIN CRYSTAL GROWTH EXPERIMENT
STS-29 protein crystal growth experiments are expected to
help advance a technology attracting intense interest from major
pharmaceutical houses, the biotech industry and agrichemical
companies.
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