Friday, June 6, 2008
Wednesday, June 4, 2008
Thuraya 3
2008-001A
Thuraya 3 is 5180 kg. 28.5E Boeing GEM satellite for regional mideast, africa, europe comms. Uses the primary gateway in Sharjah, UAE; Thuraya Sat Telecom Co. based in Abu Dhabi.
Zenit-3SL launch.
| Thuraya 3 | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 2008 Jan 15 | 1148:59 | Launch by Zenit-3SL | Odyssey |
| T+2:29 Stage 1 sep | |||
| T+3:41 Fairing sep | |||
| 1156:19 | T+8:20 Stage 2 sep | -1987 x 184 x 6.2 | |
| 1156:28 | T+8:29 DM-SL MES-1 | ||
| 1201:47 | T+12:48 MECO-1 | 180 x 889 x 6.2 | |
| 1302:08 | T+1:13:09 MES-2 | ||
| 1308:30 | T+1:19:31 MECO-2 | 736 x 35932 x 6.2 | |
| 1327:44 | T+1:38:51 DM sep | ||
| T+6:38:34 First apogee | 740 x 35786 x 6.2 | ||
| 641.60 726 x 35800 x 6.2 | |||
| 2008 Jan 18 | LAM-1 | 798.21 8471 x 35827 x 6.2 | |
| 2008 Jan 20 | LAM-2 | 1049.81 19880 x 35795 x 6.2 | |
| 2008 Jan 23? | LAM-3 | ||
| 2008 Jan 26 | 1419.50 35145 x 35776 x 6.4 | ||
| 2008 Feb 1 | 1436.02 35756 x 35814 x 6.2 GEO 98.4E | ||
Monday, June 2, 2008
Progress M-45
2001-036A
Progress mission 5P, 11F615A55 No 245, to the ISS was launched on 2001 Aug 21. It carries 1300 kg of supplies, 600 kg of fuel. It delivered MPAC/SEED, which was installed on Zvezda on the 2001 Oct 15 EVA.
| Progress M-45 | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 2001 Aug 21 | 0923:54 | Launch by Soyuz-U | KB |
| 0932:43 | Blok-I sep | ||
| 2001 Aug 23 | 0920 | Range 1 km | |
| 0943 | Range 120m, final approach | ||
| 0951:11 | Docked with Zvezda | ||
| 0959:14 | Hard dock | ||
| 2001 Aug 25 | 0740 | HO | |
| 2001 Nov 21 | 1420 | HC | |
| 2001 Nov 22 | 1612:01 | Undocked | |
| 2048:00 | Deorbited | ||
| 2124:12 | Entry | ||
STS-6: the mission
STS-6 will be launched from Complex 39's Pad A at Kennedy Space Center. The launch window in April extends from 1:30 p.m. EST, to about 1:50 p.m. EST. The window's brevity is driven by sunset at Dakar, Senegal, for a trans-Atlantic abort. The window assumes a nominal landing at Edwards Air Force Base, California. STS-6 will be launched into a 298-km (185-mi.) circular orbit with an inclination to the equator of 28.5 degrees. The total payload weight up will be approximately 20,798 kg (45,853 lb.); payload weight down is estimated at 3,719 kg (8,200 lb.) The mission is designed to last 120 hours (5 days), 19 minutes, with landing scheduled for approximately 10:49 a.m. PST at Edwards.
The five-day first flight of Challenger is requiring only three sets of liquid hydrogen and liquid oxygen tanks in the cargo bay which forms the storage portion of the Power Reactant Storage and Distribution System (PDRS) and the liquids used to activate the spacecraft’s fuel cells and provide necessary oxygen for the Environmental Control and Life Support Systems (ECLSS). The Remote Manipulator System, the 50-foot-long arm for handling payloads which can be attached and operated from the left side of the open cargo bay, is not on this flight of Challenger. It will be used in later flights. Challenger also will use a Ku-band antenna for later flights.
Challenger's primary cargo for STS-6 is the first of two Tracking and Data Relay Satellites which, by STS-9 in September 1983, will provide continuous voice and data from shuttle orbiters except for one narrow patch of "loss of signal" over Asia. The TDRS spacecraft are propelled to their geosynchronous parking orbits by Inertial Upper Stage solid-rocket two-stage boosters after deployment from Challenger's payload bay.
Mission specialists Don Peterson and Dr. Story Musgrave will don Extravehicular Mobility Units (EMU) on the fourth day of the flight to check out the new-generation shuttle spacesuits and to gain experience in simulated spacewalk tasks in the payload bay. A similar spacewalk was dropped from STS-5 when the suit pressure regulators and a fan malfunctioned.
TDRS-A is the first of three identical spacecraft which are planned for the TDRS system. The TDRS system was developed following studies in the early 1970s which showed that a system of telecommunication satellites operated from a single ground station could better support the Space Shuttle and planned scientific and application mission requirements and, at the same time also halt the spiraling cost escalation of upgrading and operating a worldwide tracking and communications network of ground stations.
In addition to the Space Shuttle, the TDRSS will be equipped to support up to 26 user satellites simultaneously and will provide two basic types of service: a multiple access service which can relay data from as many as 20 low-data-rate-user satellites simultaneously, and a single access service which will provide two high data rate communication relays.
The TDRS spacecraft will be deployed from the orbiter Challenger approximately 11 hours after launch. Transfer to geosynchronous orbit will be provided by the solid propellant Inertial Upper Stage (IUS). Separation from the upper stage occurs approximately 17 hours after launch. Required earth pointing for TDRS commands and telemetry, plus thermal control maneuvers, will be done by the upper stage between first and second stage burns.
Deployment of the solar panels, C-band antenna and space-ground-link antenna occur prior to TDRS separation from the upper stage. The single access parabolic antennas deploy after separation and subsequent to acquisition of the Sun and Earth by spacecraft sensors utilized for attitude control. Attitude and velocity adjustments place the TDRS into its final geostationary position. The TDRS is three-axis stabilized with the body fixed antennas pointing constantly at the Earth while the solar arrays track the Sun.
In addition to the Space Shuttle, the TDRSS will be equipped to support up to 26 user satellites simultaneously and will provide two basic types of service: a multiple access service which can relay data from as many as 20 low-data-rate-user satellites simultaneously, and a single access service which will provide two high data rate communication relays.
The TDRS spacecraft will be deployed from the orbiter Challenger approximately 11 hours after launch. Transfer to geosynchronous orbit will be provided by the solid propellant Inertial Upper Stage (IUS). Separation from the upper stage occurs approximately 17 hours after launch. Required earth pointing for TDRS commands and telemetry, plus thermal control maneuvers, will be done by the upper stage between first and second stage burns.
Deployment of the solar panels, C-band antenna and space-ground-link antenna occur prior to TDRS separation from the upper stage. The single access parabolic antennas deploy after separation and subsequent to acquisition of the Sun and Earth by spacecraft sensors utilized for attitude control. Attitude and velocity adjustments place the TDRS into its final geostationary position. The TDRS is three-axis stabilized with the body fixed antennas pointing constantly at the Earth while the solar arrays track the Sun.
The TDRS satellites are the largest privately owned telecommunications spacecraft ever built, each weighing about 2,268 kg (5,000 lb.). Each satellite spans more than 17.4 m (57 ft.) measuring across the solar panels. The single-access antennas, fabricated of woven molybdenum mesh and plated with 14K gold, each measure 4.9 m (16 ft.) in diameter, and when deployed, span more than 12.8 m (42 ft.) from tip to tip.
The TDRS satellites are composed of three distinct modules: an equipment module, a communications payload module, and an antenna module. The modular structure reduces the cost of individual design and construction efforts that, in turn, lowers the cost of each satellite.
The equipment module housing the subsystems that operate the satellite and the communications service is located in the lower hexagon of the spacecraft. The attitude control subsystem stabilizes the satellite so that the antennas have the proper orientation toward the Earth and the solar panels toward the Sun. The electrical power subsystem consists of two solar panels that provide a 10-year life span of approximately 1,700 watts power. The thermal control subsystem consists of surface coatings and controlled electric heaters.
The communications payload module is composed of the electronic equipment and associated antennas required for linking the user spacecraft with the ground terminal. The receivers and transmitters are mounted in compartments on the back of the single-access antennas to reduce complexity and possible circuit losses.
The antenna module is composed of four antennas. For single-access services, each TDRS satellite has two dual-feed S-band/Ku-band deployable parabolic antennas. These antennas are 4.9 m (16 ft.) attached on two axes that can move horizontally or vertically to focus the beam on orbiting spacecraft below. Those antennas are used primarily to relay communications to and from user spacecraft. The high bit-rate service made possible by these antennas is available to users on a time-shared basis.
Each antenna simultaneously supports two user spacecraft services (one at S-band and one at Ku-band). For multiple-access service, the multi-element S-band phased array of helical radiators is mounted on the satellite body. The multiple-access forward link (between TDRS and the user spacecraft) transmits command data to the user spacecraft. In the return link, the signal outputs from the array elements are sent separately to the White Sands Ground Terminal parallel processors.
A fourth antenna, a 2-m (6.5-ft.) parabolic reflector, provides the prime link for relaying transmissions to and from the ground terminal at Ku-band. The satellites are the first designed to handle telecommunications services through three frequency bands: S, Ku, and C.
The TDRSS network will have all three satellites in geosynchronous orbit, over the equator. TDRS East will be located at 41 degrees west longitude over the Atlantic Ocean; TDRS West will be 171 degrees west longitude, about mid-Pacific Ocean. The position of the TDRS in-orbit spare tentatively has been assigned a location of 79 degrees west longitude, which is over the Pacific just off the coast of South America. The second TDRS satellite is scheduled for launch in June 1983, on STS-8, with TDRS-C scheduled for March 1984 on STS-12.
The TDRS satellites are composed of three distinct modules: an equipment module, a communications payload module, and an antenna module. The modular structure reduces the cost of individual design and construction efforts that, in turn, lowers the cost of each satellite.
The equipment module housing the subsystems that operate the satellite and the communications service is located in the lower hexagon of the spacecraft. The attitude control subsystem stabilizes the satellite so that the antennas have the proper orientation toward the Earth and the solar panels toward the Sun. The electrical power subsystem consists of two solar panels that provide a 10-year life span of approximately 1,700 watts power. The thermal control subsystem consists of surface coatings and controlled electric heaters.
The communications payload module is composed of the electronic equipment and associated antennas required for linking the user spacecraft with the ground terminal. The receivers and transmitters are mounted in compartments on the back of the single-access antennas to reduce complexity and possible circuit losses.
The antenna module is composed of four antennas. For single-access services, each TDRS satellite has two dual-feed S-band/Ku-band deployable parabolic antennas. These antennas are 4.9 m (16 ft.) attached on two axes that can move horizontally or vertically to focus the beam on orbiting spacecraft below. Those antennas are used primarily to relay communications to and from user spacecraft. The high bit-rate service made possible by these antennas is available to users on a time-shared basis.
Each antenna simultaneously supports two user spacecraft services (one at S-band and one at Ku-band). For multiple-access service, the multi-element S-band phased array of helical radiators is mounted on the satellite body. The multiple-access forward link (between TDRS and the user spacecraft) transmits command data to the user spacecraft. In the return link, the signal outputs from the array elements are sent separately to the White Sands Ground Terminal parallel processors.
A fourth antenna, a 2-m (6.5-ft.) parabolic reflector, provides the prime link for relaying transmissions to and from the ground terminal at Ku-band. The satellites are the first designed to handle telecommunications services through three frequency bands: S, Ku, and C.
The TDRSS network will have all three satellites in geosynchronous orbit, over the equator. TDRS East will be located at 41 degrees west longitude over the Atlantic Ocean; TDRS West will be 171 degrees west longitude, about mid-Pacific Ocean. The position of the TDRS in-orbit spare tentatively has been assigned a location of 79 degrees west longitude, which is over the Pacific just off the coast of South America. The second TDRS satellite is scheduled for launch in June 1983, on STS-8, with TDRS-C scheduled for March 1984 on STS-12.
The first scheduled user of the TDRSS network is the Landsat 4 Earth resources satellite, which was launched from Vandenberg Air Force Base, Calif., July 16, 1982. Landsat 4 is an experimental spacecraft with powerful remote-sensing capabilities from both a multi-spectral scanner and a thematic mapper. Other major users of the TDRSS include Spacelab and the Space Telescope.
Other future users of the TDRSS network will include the Cosmic Background Explorer (COBE), which will explore the diffuse cosmic background radiation of the universe; Gamma Ray Observatory (GRO), which will make a high-sensitivity survey of the galactic plane to study galactic structure, gamma-ray emission and spatial variations; Earth Radiation Budget Experiment (ERBE), which will obtain an accurate measurement of the Earth's monthly radiation budget for the upper atmosphere and for regional, zonal, and global spatial scales; and the Upper Atmosphere Research Satellite (UARS), which will study the chemistry and physical processes acting upon and within the stratosphere, mesosphere and the lower thermosphere.
The ground station network now in operation by NASA is able to provide communications support for only a small fraction (typically 15 percent) of the orbital period. The TDRSS network, when established, should provide coverage for almost the entire orbital period of a user spacecraft. The TDRSS does no processing of user traffic, in either direction. Thus, the TDRSS operates as a "bent-pipe" repeater; in other words, it relays signals and data between the user spacecraft and ground terminal.
A TDRSS ground terminal has been built at White Sands, N.M., which provides a location at a longitude with a clear line-of-sight to the TDRSS satellites and a place where rain conditions do not interfere with the availability of the K-band uplink and downlink channels. Also-located at White Sands is the NASA Ground Terminal (NGT), which provides the interface between the TDRSS and the other TDRSS network elements which have their primary tracking and communication facilities at Goddard Space Flight Center in Greenbelt, Maryland.
Also located at Goddard are the Network Control Center (NCC), which provides system scheduling and is the focal point for NASA communications with the TDRSS and the other TDRSS network elements; the operating Support Computing Facility (OSCF), which provides the network with orbital predictions and definitive orbit calculations for user spacecraft and the TDRSS; and the NASA Communications Network (NASCOM), which provides the common carrier interface at network locations and consists of domestic satellites and their interface through Earth terminals at Goddard, White Sands, and the Johnson Space Center in Houston, Texas.
The Network Control Center at Goddard contains data processing equipment and software. Console operators monitor the data, schedule emergency interfaces, isolate faults in the system, account for the system, test the system, and simulate user spacecraft. The user services available from the TDRSS network are sent through the NASA Communications Network (NASCOM), a global system that provides long-line operational communications support to all NASA projects. It offers voice, data, and teletype links with the TDRSS network, the Ground Spaceflight Tracking and Data Network (GSTDN) and the user spacecraft control centers. NASCOM's circuits are provided and operated by commercial carriers under contract to NASCOM, which sends the TDRSS user data to the Operations Support Computer Facility (OSCF) and to the Sensor Data Processing Facility (SDPF), also at Goddard.
The Sensor Data Processing Facility receives the telemetry and image data directly from the users through TDRSS or a ground station via the NASCOM or from magnetic tapes recorded and mailed from a ground station. At the Sensor Data Processing Facility the data are processed and distributed, including editing, time tagging, decommutating, formatting, and applying ancillary data. In addition, selected data are monitored for fault isolation.
All of the telemetry data are routed directly to a user's Payload Operations Control Center (POCC). Each payload center is tailored to a specific space mission, providing support to one spacecraft or to a series of spacecraft in a project. Scientists, engineering and other technical experts in the center process experiment status, command and telemetry; handle attitude data for proper orientation of cameras and measuring instruments in the payload; control the payload operations and instrument sensors; and plan and analyze the mission.
The Payload operations Control Center interfaces directly with the scientific investigators to plan payload experiment operations and to determine support requirements. Thus, a coordinated ground effort exists between the TDRSS network's NASA Ground Terminal, Network Control Center, the NASA Communications Network, and each Payload Operations Control Center to unite users with their spacecraft for command, telemetry, and data.
Other future users of the TDRSS network will include the Cosmic Background Explorer (COBE), which will explore the diffuse cosmic background radiation of the universe; Gamma Ray Observatory (GRO), which will make a high-sensitivity survey of the galactic plane to study galactic structure, gamma-ray emission and spatial variations; Earth Radiation Budget Experiment (ERBE), which will obtain an accurate measurement of the Earth's monthly radiation budget for the upper atmosphere and for regional, zonal, and global spatial scales; and the Upper Atmosphere Research Satellite (UARS), which will study the chemistry and physical processes acting upon and within the stratosphere, mesosphere and the lower thermosphere.
The ground station network now in operation by NASA is able to provide communications support for only a small fraction (typically 15 percent) of the orbital period. The TDRSS network, when established, should provide coverage for almost the entire orbital period of a user spacecraft. The TDRSS does no processing of user traffic, in either direction. Thus, the TDRSS operates as a "bent-pipe" repeater; in other words, it relays signals and data between the user spacecraft and ground terminal.
A TDRSS ground terminal has been built at White Sands, N.M., which provides a location at a longitude with a clear line-of-sight to the TDRSS satellites and a place where rain conditions do not interfere with the availability of the K-band uplink and downlink channels. Also-located at White Sands is the NASA Ground Terminal (NGT), which provides the interface between the TDRSS and the other TDRSS network elements which have their primary tracking and communication facilities at Goddard Space Flight Center in Greenbelt, Maryland.
Also located at Goddard are the Network Control Center (NCC), which provides system scheduling and is the focal point for NASA communications with the TDRSS and the other TDRSS network elements; the operating Support Computing Facility (OSCF), which provides the network with orbital predictions and definitive orbit calculations for user spacecraft and the TDRSS; and the NASA Communications Network (NASCOM), which provides the common carrier interface at network locations and consists of domestic satellites and their interface through Earth terminals at Goddard, White Sands, and the Johnson Space Center in Houston, Texas.
The Network Control Center at Goddard contains data processing equipment and software. Console operators monitor the data, schedule emergency interfaces, isolate faults in the system, account for the system, test the system, and simulate user spacecraft. The user services available from the TDRSS network are sent through the NASA Communications Network (NASCOM), a global system that provides long-line operational communications support to all NASA projects. It offers voice, data, and teletype links with the TDRSS network, the Ground Spaceflight Tracking and Data Network (GSTDN) and the user spacecraft control centers. NASCOM's circuits are provided and operated by commercial carriers under contract to NASCOM, which sends the TDRSS user data to the Operations Support Computer Facility (OSCF) and to the Sensor Data Processing Facility (SDPF), also at Goddard.
The Sensor Data Processing Facility receives the telemetry and image data directly from the users through TDRSS or a ground station via the NASCOM or from magnetic tapes recorded and mailed from a ground station. At the Sensor Data Processing Facility the data are processed and distributed, including editing, time tagging, decommutating, formatting, and applying ancillary data. In addition, selected data are monitored for fault isolation.
All of the telemetry data are routed directly to a user's Payload Operations Control Center (POCC). Each payload center is tailored to a specific space mission, providing support to one spacecraft or to a series of spacecraft in a project. Scientists, engineering and other technical experts in the center process experiment status, command and telemetry; handle attitude data for proper orientation of cameras and measuring instruments in the payload; control the payload operations and instrument sensors; and plan and analyze the mission.
The Payload operations Control Center interfaces directly with the scientific investigators to plan payload experiment operations and to determine support requirements. Thus, a coordinated ground effort exists between the TDRSS network's NASA Ground Terminal, Network Control Center, the NASA Communications Network, and each Payload Operations Control Center to unite users with their spacecraft for command, telemetry, and data.
The Inertial Upper Stage (IUS) will be used to place NASA's Tracking and Data Relay Satellite TDRS-A into geosynchronous earth orbit. The STS-6 crew will begin deployment activities approximately nine hours after Challenger reaches a low earth
orbit of 283 km (153 nm). Upper stage airborne support equipment, located in the orbiter payload bay, will be used to position the IUS/TDRS-A combined vehicle into the proper deployment attitude -- an angle of 59 degrees -- and "kick" it into low Earth orbit. Deployment will be by a spring eject system.
Following deployment from Challenger's payload bay, the orbiter will move away from the IUS/TDRS-A to a safe distance. The first stage will fire about 55 minutes after deployment from the payload bay. Following the aft (first) stage burn of two minutes 33 seconds, the solid fuel motor shuts down and the two stages separate. After coasting for several hours the forward (second) stage motor ignites at six hours 12 minutes after deployment for the final push to higher orbit. Following a 1-minute, 44-second burn, the forward stage will shut down as the IUS/TDRS-A reaches the predetermined geosynchronous orbit position.
Six hours 54 minutes after deployment from Challenger the forward stage will separate from the TDRS-A and perform an anti-collision maneuver with its on board reaction control system. After the IUS upper stage reaches a safe distance from the TDRS, the stage will relay performance data back to a NASA tracking station and then shut itself down seven hours five minutes after deployment from the payload bay.
A number of advanced features distinguish the IUS from other previous upper stages. It has the first completely redundant avionics system ever developed for an unmanned space vehicle. The system has the capability to 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 in which the second computer is capable of taking over functions from the primary computer if necessary.
Originally intended as a temporary substitute for a reusable space tug when it was designed in the 1970s, the IUS booster was dubbed the “Interim” Upper Stage and later became “Inertial” in recognition of its inertial guidance system. Losing its “interim” status also reflected a growing awareness, when the space tug was cancelled in late 1977, that the IUS’ services would be needed throughout the 1980s.
Physically, IUS is 5.18 m (17 ft.) long, 2.7 m (9 ft.) in diameter, and weighs more than 14,515 kg (32,000 lb.). The NASA version of the IUS contains 12,247 kg (27,000 lb.) of solid fuel propellant. The IUS consists of an aft skirt; an aft (first) stage that contains 9,707 kg (21,400 lb.) of solid propellant fuel and generates 20,685 kg (45,600 lb.) of thrust; an interstage; a forward (second) stage that contains 2,720 kg (6,000 lb.) of propellant and generates 8,390 kg (18,500 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.
Solid propellant rocket motors were selected in the design of the IUS because of their compactness, simplicity, inherent safety, demonstrated reliability and lower cost. Hydrazine-fed reaction control thrusters provide the IUS with additional stability during the coasting phase between first and second stage firings, as well as ensuring accurate roll control and assisting with the satellite payload’s insertion into geosynchronous orbit.
During the IUS’ development, obstacles have been encountered with its propulsion system, including burst cases, tacky liners, soft and cracked propellants and nozzle delaminations, together with problems with its onboard software and avionics. The first operational use of the booster was supposed to be on the shuttle with TDRS-A, although delays and scheduling conflicts caused it to be leapfrogged by a pair of military communications satellites on an Air Force Titan 34D launched October 30, 1982. In spite of telemetry dropouts, that IUS mission proved successful.
orbit of 283 km (153 nm). Upper stage airborne support equipment, located in the orbiter payload bay, will be used to position the IUS/TDRS-A combined vehicle into the proper deployment attitude -- an angle of 59 degrees -- and "kick" it into low Earth orbit. Deployment will be by a spring eject system.
Following deployment from Challenger's payload bay, the orbiter will move away from the IUS/TDRS-A to a safe distance. The first stage will fire about 55 minutes after deployment from the payload bay. Following the aft (first) stage burn of two minutes 33 seconds, the solid fuel motor shuts down and the two stages separate. After coasting for several hours the forward (second) stage motor ignites at six hours 12 minutes after deployment for the final push to higher orbit. Following a 1-minute, 44-second burn, the forward stage will shut down as the IUS/TDRS-A reaches the predetermined geosynchronous orbit position.
Six hours 54 minutes after deployment from Challenger the forward stage will separate from the TDRS-A and perform an anti-collision maneuver with its on board reaction control system. After the IUS upper stage reaches a safe distance from the TDRS, the stage will relay performance data back to a NASA tracking station and then shut itself down seven hours five minutes after deployment from the payload bay.
A number of advanced features distinguish the IUS from other previous upper stages. It has the first completely redundant avionics system ever developed for an unmanned space vehicle. The system has the capability to 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 in which the second computer is capable of taking over functions from the primary computer if necessary.
Originally intended as a temporary substitute for a reusable space tug when it was designed in the 1970s, the IUS booster was dubbed the “Interim” Upper Stage and later became “Inertial” in recognition of its inertial guidance system. Losing its “interim” status also reflected a growing awareness, when the space tug was cancelled in late 1977, that the IUS’ services would be needed throughout the 1980s.
Physically, IUS is 5.18 m (17 ft.) long, 2.7 m (9 ft.) in diameter, and weighs more than 14,515 kg (32,000 lb.). The NASA version of the IUS contains 12,247 kg (27,000 lb.) of solid fuel propellant. The IUS consists of an aft skirt; an aft (first) stage that contains 9,707 kg (21,400 lb.) of solid propellant fuel and generates 20,685 kg (45,600 lb.) of thrust; an interstage; a forward (second) stage that contains 2,720 kg (6,000 lb.) of propellant and generates 8,390 kg (18,500 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.
Solid propellant rocket motors were selected in the design of the IUS because of their compactness, simplicity, inherent safety, demonstrated reliability and lower cost. Hydrazine-fed reaction control thrusters provide the IUS with additional stability during the coasting phase between first and second stage firings, as well as ensuring accurate roll control and assisting with the satellite payload’s insertion into geosynchronous orbit.
During the IUS’ development, obstacles have been encountered with its propulsion system, including burst cases, tacky liners, soft and cracked propellants and nozzle delaminations, together with problems with its onboard software and avionics. The first operational use of the booster was supposed to be on the shuttle with TDRS-A, although delays and scheduling conflicts caused it to be leapfrogged by a pair of military communications satellites on an Air Force Titan 34D launched October 30, 1982. In spite of telemetry dropouts, that IUS mission proved successful.
The Extravehicular Activity planned for STS-6 is virtually a replay of that which had been planned for STS-5 and scrubbed because of equipment problems. Mission specialists Donald Peterson and Dr. Story Musgrave will enter the airlock and don Extravehicular Mobility Units before pre-breathing 100 percent oxygen for three hours. The orbiter cabin will remain pressurized at 14.7 psi during the extravehicular activity, planned for the fourth day of the flight.
After depressurizing the airlock to space vacuum, Peterson and Musgrave will attach safety tethers prior to moving aft along the hinge line slide wires to the aft bulkhead, one observing the other as each translates aft. Spacesuit status checks are scheduled throughout the extravehicular activity. En route to the aft bulkhead, both crewmen will inspect the now empty IUS cradle and evaluate payload bay lighting, suit radio communications and other aspects affecting future extravehicular activities.
Translating forward to a work station and toolbox, both will next evaluate unstowage and handling of tools adapted or built for extravehicular activity use. While at the work station, spacesuit joint mobility and reach, and suit-to-body zero-g pressure points will be evaluated.
Both crewmen next move again to the aft bulkhead where they rig the aft winch cable through rollers and a snatch block to the IUS cradle to simulate contingency restowing of a stuck IUS cradle. Against the forward bulkhead, the crewmen operate the forward winch against an "Exergenie" acting as a dummy load on the winch line. A bag of tools will be transformed into a sort of space barbell in an evaluation of moving an object of large mass as one crewman tows the tool bag to the aft bulkhead and back again.
Tools and equipment restowed, both men enter the airlock, close the hatch and repressurize to cabin pressure, ending the extravehicular activity at three and a half to four hours elapsed time.
After depressurizing the airlock to space vacuum, Peterson and Musgrave will attach safety tethers prior to moving aft along the hinge line slide wires to the aft bulkhead, one observing the other as each translates aft. Spacesuit status checks are scheduled throughout the extravehicular activity. En route to the aft bulkhead, both crewmen will inspect the now empty IUS cradle and evaluate payload bay lighting, suit radio communications and other aspects affecting future extravehicular activities.
Translating forward to a work station and toolbox, both will next evaluate unstowage and handling of tools adapted or built for extravehicular activity use. While at the work station, spacesuit joint mobility and reach, and suit-to-body zero-g pressure points will be evaluated.
Both crewmen next move again to the aft bulkhead where they rig the aft winch cable through rollers and a snatch block to the IUS cradle to simulate contingency restowing of a stuck IUS cradle. Against the forward bulkhead, the crewmen operate the forward winch against an "Exergenie" acting as a dummy load on the winch line. A bag of tools will be transformed into a sort of space barbell in an evaluation of moving an object of large mass as one crewman tows the tool bag to the aft bulkhead and back again.
Tools and equipment restowed, both men enter the airlock, close the hatch and repressurize to cabin pressure, ending the extravehicular activity at three and a half to four hours elapsed time.
The Continuous Flow Electrophoresis System, the first commercial experiment flown aboard the Space Shuttle, makes a return visit to space on STS-6. In addition to experimentation by the company, this flight marks the first use of the device by NASA scientists to expand the knowledge base of electrophoretic separation processes and further characterize the effects of gravity on continuous flow electrophoresis.
NASA's use of the system for its own research is part of the consideration provided to the space agency under the terms of the NASA/McDonnell Douglas Joint Endeavor Agreement. This agreement provides a vehicle for private enterprise and NASA to work together to promote the utilization of space where a technological advancement is needed and there is a potential commercial application.
During this flight McDonnell Douglas will seek to verify that the device separates materials to purity levels four times higher than those possible on earth. McDonnell Douglas separated samples of rat and egg albumin and cell culture fluid in the device during the STS-4 flight. Similar model protein samples will be separated on this flight.
NASA's first sample, which will be the initial sample to be run in the device during the mission, is a high concentration of hemoglobin and will be used to evaluate the flow profile during the continuous flow electrophoresis unit operating in weightlessness. The second NASA sample, a mixture of hemoglobin and a polysaccharide, is intended to evaluate resolution of the separation and investigate separation of different molecular configurations.
The agreement provides that general equipment performance data and the results from NASA's experiments using the device will be made public.
The electrophoresis system, developed by the McDonnell Douglas Astronautics Co., St. Louis, Mo., and initially carried into space on STS-4, has the potential for separating biological materials for both research and the production of pharmaceuticals. The device is designed to separate biological materials according to their surface electrical charge as they pass through an electric field. Unlike previous electrophoresis experiments conducted in space on the Apollo-Soyuz Test Project and on STS-2, this device processes large quantities of materials carried in a continuous stream.
NASA's use of the system for its own research is part of the consideration provided to the space agency under the terms of the NASA/McDonnell Douglas Joint Endeavor Agreement. This agreement provides a vehicle for private enterprise and NASA to work together to promote the utilization of space where a technological advancement is needed and there is a potential commercial application.
During this flight McDonnell Douglas will seek to verify that the device separates materials to purity levels four times higher than those possible on earth. McDonnell Douglas separated samples of rat and egg albumin and cell culture fluid in the device during the STS-4 flight. Similar model protein samples will be separated on this flight.
NASA's first sample, which will be the initial sample to be run in the device during the mission, is a high concentration of hemoglobin and will be used to evaluate the flow profile during the continuous flow electrophoresis unit operating in weightlessness. The second NASA sample, a mixture of hemoglobin and a polysaccharide, is intended to evaluate resolution of the separation and investigate separation of different molecular configurations.
The agreement provides that general equipment performance data and the results from NASA's experiments using the device will be made public.
The electrophoresis system, developed by the McDonnell Douglas Astronautics Co., St. Louis, Mo., and initially carried into space on STS-4, has the potential for separating biological materials for both research and the production of pharmaceuticals. The device is designed to separate biological materials according to their surface electrical charge as they pass through an electric field. Unlike previous electrophoresis experiments conducted in space on the Apollo-Soyuz Test Project and on STS-2, this device processes large quantities of materials carried in a continuous stream.
The Monodisperse Latex Reactor (MLR), is a materials processing in space experiment carried and operated in the middeck area of the orbiter cabin. The purpose of this experiment is to study the kinetics involved with the production of uniformly sized (monodisperse) latex beads (tiny spheres) in a low-gravity environment where the effects of buoyancy and sedimentation are minimized.
The experiment consists of four, 0.3-m (1-ft.) tall reactors, each containing a chemical latex-forming recipe, housed in a 0.6-m (2-ft.) tall metal cylinder. The recipe consists of a suspension of very small latex beads in water plus other chemical ingredients which cause the beads to polymerize when the experiment is activated on orbit.
The reactor was carried into space on two previous Shuttle missions. The experiment worked on its maiden voyage in space on STS-3 and produced quantities of 5-micron latex particles. During the STS-4 flight, the chemical processing was not completed because of a hardware malfunction. Engineers have since identified the malfunction and have made necessary modifications. On STS-6, the experiment will study the effects of varying processing parameters to better understand limitations in producing uniformly larger diameter spheres on earth. Latex spheres up to 10 microns in diameter are expected to be obtained.
Monodispersed particles may have medical and industrial research applications. Some of the proposed applications of the latex beads include measuring the size of pores in the wall of the intestine in cancer research; measuring the size of pores in the human eye in glaucoma research; and as a carrier of drugs and radioactive isotopes for treatment of cancerous tumors. The National Bureau of Standards has also indicated its interest in routine use of the beads as calibration standards in medical and scientific equipment.
Prior to launch, each of the reactors is loaded with 100 cubic centimeters of the chemical latex forming recipe. A small onboard computer will control the experiment after the Shuttle crew turns it on. In orbit, the latex mixture is heated to a constant 70-degree centigrade which initiates a chemical reaction to form the larger plastic beads. A recorder will store all data produced during operation of the experiment. The experiment requires about 20 hours of processing time. The reactor will be removed from the Challenger at the landing site and returned to the experimenters for sample and data analysis.
The experiment consists of four, 0.3-m (1-ft.) tall reactors, each containing a chemical latex-forming recipe, housed in a 0.6-m (2-ft.) tall metal cylinder. The recipe consists of a suspension of very small latex beads in water plus other chemical ingredients which cause the beads to polymerize when the experiment is activated on orbit.
The reactor was carried into space on two previous Shuttle missions. The experiment worked on its maiden voyage in space on STS-3 and produced quantities of 5-micron latex particles. During the STS-4 flight, the chemical processing was not completed because of a hardware malfunction. Engineers have since identified the malfunction and have made necessary modifications. On STS-6, the experiment will study the effects of varying processing parameters to better understand limitations in producing uniformly larger diameter spheres on earth. Latex spheres up to 10 microns in diameter are expected to be obtained.
Monodispersed particles may have medical and industrial research applications. Some of the proposed applications of the latex beads include measuring the size of pores in the wall of the intestine in cancer research; measuring the size of pores in the human eye in glaucoma research; and as a carrier of drugs and radioactive isotopes for treatment of cancerous tumors. The National Bureau of Standards has also indicated its interest in routine use of the beads as calibration standards in medical and scientific equipment.
Prior to launch, each of the reactors is loaded with 100 cubic centimeters of the chemical latex forming recipe. A small onboard computer will control the experiment after the Shuttle crew turns it on. In orbit, the latex mixture is heated to a constant 70-degree centigrade which initiates a chemical reaction to form the larger plastic beads. A recorder will store all data produced during operation of the experiment. The experiment requires about 20 hours of processing time. The reactor will be removed from the Challenger at the landing site and returned to the experimenters for sample and data analysis.
STS-6: the crew
CDR Paul Joseph “P.J.” Weitz, Captain USN, ret., was born in Erie, Pennsylvania, on July 25, 1932, where he attended McKinley Elementary School and in 1950 graduated from nearby Harborcreek High School. He received a Bachelor of Science degree in Aeronautical Engineering from Pennsylvania State University in 1954 and a master’s degree in Aeronautical Engineering from the U.S. Naval Postgraduate School in Monterrey, California, in 1964.
Weitz retired from the Navy in 1976 with 22 years of service. In 1954 he had received his commission as an ensign through the Naval ROTC program at Penn State. He served for one year at sea aboard a destroyer before going to flight training and was awarded his wings in September 1956. Weitz was an A-4 tactics instructor at the Naval Air Station in Jacksonville, Florida, from 1956 to 1960, a project officer at China Lake, California, in various air-to-ground delivery tactic projects from 1960 to 1962. After having received his master’s degree in 1964, Weitz also flew combat missions in Vietnam and served as detachment officer-in-charge at Whidbey Island. He logged more than 6,200 hours flying time – 5,100 hours in jet aircraft.
Paul Weitz was one of the 19 astronauts selected by NASA in April 1966. Michael Cassutt described his first assignments, “Weitz specialized in the Apollo Command and Service Module system. He served as CapCom for Apollo 12 and had been informally selected as backup CMP for Apollo 17 (putting him in line for a flight to the Moon on Apollo 20) when Congressional budget cuts eliminated that mission. In 1970 he began to work on the Apollo Applications Program Saturn Workshop, later known as Skylab, and was officially selected as pilot of Skylab 2 in January 1972.”
Skylab 2, the first manned Skylab mission, was launched on May 25, 1973 and ended on June 22, 1973. Joining Weitz for the initial on-orbit repair, activation and 28-day flight qualification operations of Skylab were spacecraft commander Charles Conrad and science pilot Joseph Kerwin. In logging 672 hours and 49 minutes aboard the workshop, the crew established a new world record for a single mission. Weitz also logged two hours and 11 minutes in extravehicular activities.
Paul Weitz later admitted feeling really glad having been able to take command of NASA’s newest addition to the shuttle fleet in 1983. “As a crew we were glad to have the opportunity. It's a little distinction. Each crew, each mission looks for some distinction you like to hang your hat on. Flying the inaugural flight or the maiden flight with Challenger, we thought it was a good deal.”
As to the rest of the STS-6 crew assignments, Paul Weitz later explained he didn’t have any input. “The four names were just, ‘There they are. This is the F crew.’ It was Weitz, Bobko, Musgrave, and Peterson. So, no. As opposed to in Apollo, I think – it’s my understanding that the commanders, once they flew, well, they had to fly before. Typically they flew before being assigned as commander, and they had strong input into crew makeup.” He explained, “For example, Pete Conrad's first flight was with Gordo Cooper. After that, Pete's crew was always all Navy. He obviously had a strong input into the crew makeup. Because I wasn't a mission commander; I was the head of this F crew, but if we did fly, then the people were going to fly in these positions. I was going to get to fly. I never did care that much and I had confidence in the other three guys.”
- PLT Karol Joseph “Bo” Bobko, Colonel USAF, was born in New York City on December 23, 1937, and graduated Brooklyn Technical High School in 1955. He received a Bachelor of Science degree from the Air Force Academy in 1959 and a Master of Science degree in Aerospace Engineering from the University of Southern California in 1970. Bobko received his wings in 1960 and from 1961 to 1965 flew F-100 and F-105 aircraft at Cannon AFB, New Mexico, and Seymore Johnson AFB, North Carolina. He then attended the Aerospace Research Pilots School at Edwards Air Force Base and in June 1966 was assigned as an astronaut in the USAF Manned Orbiting Laboratory program.
STS-6 was his first spaceflight, but Karol Bobko had already logged over 4,800 hours of flying time in the F-100, F-104, F-105, T-33 and T-38. In 1970, after he had transferred to NASA after the cancellation of the MOL program a year earlier, Bobko became a crewmember on the Skylab Medical Experiments Altitude Test (SMEAT) – a 56-day simulation of a Skylab mission, enabling crewmen to collect medical experiments baseline data and evaluate equipment, operations and procedures. He was joined by astronauts Robert Crippen and William Thornton. Bobko was also a member of the astronaut support crew for the joint U.S./Soviet ASTP mission in 1975.
Karol Bobko then became support crewmember for the shuttle Approach and Landing Test program and was assigned to the Orbital Flight Test group involved with ground tests and checkout of the orbiter Columbia. He worked as CapCom and chase pilot. But being assigned for his first spaceflight changed his outlook a lot, as he explained in a 2002 interview for the JSC Oral History Project. “It just changes the way you look at things. It’s not something out there in the mist; it’s up close and personal. So I think, you know, there’s a lot to be learned for a spaceflight, and it doesn’t seem like there’s ever enough time. You feel you want to learn it all, and it gives you a lot of incentive to work hard and try to learn as much as you can and get things as squared away as you can.”
MS1/EV1 Franklin Story Musgrave, MD, was born August 19, 1935, in Boston, Massachusetts, but considered Lexington, Kentucky., to be his hometown. He graduated from St. Mark’s School, Southborough, Massachusetts, in 1953. Musgrave received a Bachelor of Science degree in Mathematics and Statistics from Syracuse University in 1958, a Master of Business Administration degree in Operations Analysis and Computer Programming from the University of California at Los Angeles in 1959, a Bachelor of Arts degree in Chemistry from Marietta College in 1960, a doctorate in Medicine from Columbia University in 1964, and a Master of Science in Physiology and Biophysics from the University of Kentucky in 1966.
Also, following graduation from high school in 1953, Musgrave entered the Unites States Marine Corps and completed basic training at Parris Island, South Carolina. He completed training at the U.S. Naval Airman Preparatory School and the U.S. Naval Aviation Electrician and Instrument Technician School in Jacksonville, Florida. He served as an aviation electrician and instrument technician and as an aircraft crew chief while completing duty assignments in Korea, Japan, Hawaii, and aboard the carrier USS Wasp in the Far East.
By April 1979 Musgrave had flown 90 different types of civilian and military aircraft, logging over 10,800 hours flying time, including 4,300 in jet aircraft, and he held instructor, instrument instructor, glider instructor, and airline transport ratings. An accomplished parachutist, he made more than 330 freefalls – including over 100 experimental freefall descents involved with the study of human aerodynamics. He held an International Jumpmaster Class C license and was President and Jumpmaster of the Bluegrass Sport Parachuting Association in Lexington, Kentucky, from 1964 to 1967.
Story Musgrave was employed as a mathematician and operations analyst by the Eastman Kodak Company, Rochester, New York, during 1958. He served a surgical internship at the University of Kentucky Medical Center in Lexington from 1964 to 1965. He continued there as a USAF postdoctoral fellow (1965 to 1966), working in aerospace medicine and physiology and as a National Heart Institute postdoctoral fellow (1966 to 1967), teaching and doing research in cardiovascular and exercise physiology. Musgrave had written 30 scientific papers in the areas of aerospace medicine and physiology, temperature regulation, exercise physiology and clinical surgery.
Dr. Musgrave was selected as one of 11 scientist astronauts in August 1967, “at a time when NASA was planning an ambitious series of Apollo lunar landings and scientific missions in Earth orbit,” said Michael Cassutt. “Within months budget cuts forced on NASA because of the Vietnam War eliminated most of the scientist astronauts’ flight opportunities.”
Musgrave completed astronaut academic training and a year of military flight training. He worked on the design and development of the Skylab program and became backup science pilot for Skylab 2. He served as CapCom for the Skylab 2 and 3 missions. From 1974 he was working on the development of the Space Shuttle; Musgrave was Mission Specialist on the first and second Spacelab Mission Simulations. He participated in the design and development of all shuttle EVA equipment, including spacesuits, life support systems, airlocks, and Manned Maneuvering Units. From 1979 to 1982 Musgrave was involved in testing computer software at the Shuttle Avionics Integration Laboratory.
While preparing for future space missions, Musgrave continued clinical and scientific training as a part-time surgeon at the Denver General Hospital and was a part-time professor of physiology and biophysics at the University of Kentucky Medical Center.
Married to the former Patricia Marguerite Van Kirk of Patterson, New Jersey, Story Musgrave also was a father of five children: Lorelei Lisa (March 21, 1961), Bradley Scott (July 3, 1962), Holly Kay (December 13, 1963), Christopher Todd (May 12, 1965), and Jeffrey Paul (June 19, 1967). Among his recreational interests he listed bicycling, chess, flying, gardening, long-distance running, motorcycling, parachuting, photography, scuba diving, skateboarding, and soaring.
MS2/EV2 Donald Herod “Don” Peterson, Colonel USAF, ret., was born in Winona, Mississippi, on October 22, 1933, where he graduated from Winona City High School. In 1955 he received a Bachelor of Science degree from the United States Military Academy in West Point, New York, and later, in 1962, a master’s degree in Nuclear Engineering from the Air Force Institute of Technology, Wright-Patterson AFB, Ohio.
Astronaut biographer Michael Cassutt said, “Peterson elected to serve in the Air Force, and, after pilot training, served as an instructor with the Air Training Command until 1960.” After four years as a military training officer, Peterson continued three years as a nuclear systems analyst with the Air Force Systems Command. He was also a pilot with the Tactical Air Command and graduated from the Aerospace Research Pilot School at Edwards AFB before being assigned to the Air Force Manned Orbiting Laboratory program in June 1967.
Also belonging to this third selection group of MOL astronauts was Major USAF James Alan Abrahamson, who since 1981 had been in charge of the Space Shuttle program and was soon to become the head of President Reagan’s “Star Wars” program – the Strategic Defense Initiative. Other than Abrahamson, after the cancellation of MOL in 1969, Donald Peterson had joined the NASA astronaut corps. He served in the astronaut support crew for Apollo 16 before being assigned to the shuttle program.
Astronaut biographer Michael Cassutt said, “Peterson elected to serve in the Air Force, and, after pilot training, served as an instructor with the Air Training Command until 1960.” After four years as a military training officer, Peterson continued three years as a nuclear systems analyst with the Air Force Systems Command. He was also a pilot with the Tactical Air Command and graduated from the Aerospace Research Pilot School at Edwards AFB before being assigned to the Air Force Manned Orbiting Laboratory program in June 1967.
Also belonging to this third selection group of MOL astronauts was Major USAF James Alan Abrahamson, who since 1981 had been in charge of the Space Shuttle program and was soon to become the head of President Reagan’s “Star Wars” program – the Strategic Defense Initiative. Other than Abrahamson, after the cancellation of MOL in 1969, Donald Peterson had joined the NASA astronaut corps. He served in the astronaut support crew for Apollo 16 before being assigned to the shuttle program.
STS-6: introduction
The STS-6 flight, the first space voyage of Challenger, is symbolized by the hexagonal shape of its crew emblem. The overall color theme of the patch is a patriotic red, white and blue. It has a border of royal blue, which surrounds an inner band of white. This inner band is bordered on the interior by a thin red line. This band lists, in royal blue to match the border, the surnames of Challenger’s four crew members – astronauts Paul J. Weitz, Karol J. Bobko, F. Story Musgrave, and Donald H. Peterson – along with the mission’s sequence numeral and the name of the spacecraft in the inner line’s red color.
The center area of the patch is dominated by a spacescape, which depicts the orbiter flying in the foreground as it creates an orbital path from behind the Earth. The planet is depicted as a large, light-blue sphere, rimmed with a slightly darker blue. The orbiter is seen in a side – and slightly frontal – view with the payload bay doors open. The Tracking and Data Relay Satellite, combined with the Inertial Upper Stage, is depicted during its deployment from the Challenger’s cargo bay. It trails a white streamer behind the far side of the globe, just as Challenger trails a red one. Both the orbiter and the TDRS are shown in shades of white, with light blue shading and black detail. The IUS has got a band of red on its exterior.
Slightly above and behind Challenger are shining white stars which form the constellation Virgo. These six stars against a background of deep navy blue represent the mission sequence number – whereby the five stars to the right of the vertical tail symbolize Columbia’s five trips into space, the lone star to the left the first use of the newest member of the Space Shuttle fleet. Virgo itself is also symbolic of the maiden flight of Challenger.
The spacecraft Challenger was the “Early Bird” of America’s Space Transportation System’s Earth-orbiting fleet. Structural fabrication of Challenger had commenced on January 6, 1975, about a year earlier than the origin of Columbia. In several transitional periods Challenger went from structural assembly to becoming the Structural Test Article (STA-099), then back into manufacturing modification period for renovation and uprating to “flight worthy” status to final assembly.
Rockwell’s original $2.6 billion contract had authorized the building of a pair of static test articles (MPTA-098 and STA-099) and two initial flight test vehicles (OV-101 and OV-102). The 1978 decision not to modify Enterprise from her ALT configuration would leave only one space-rated orbiter. This vehicle, Columbia, was rolled out of the Palmdale plant on March 8, 1979.
While Enterprise and MPTA-098 were undergoing tests, Lockheed-California in Palmdale was busy trying to verify the structural integrity of STA-099. On February 4, 1978, Rockwell had delivered the nearly-complete airframe to the Lockheed-California Company located across the runway at Plant 42. Twelve months of testing would take place in a 43-ton steel rig built especially for the Space Shuttle test program.
The test rig contained 256 hydraulic jacks, distributed over 836 load application points, which simulated various stress levels under control of a computer. These stress levels duplicated the launch, ascent, on-orbit, reentry and landing phases of flight. Three 1,000,000 pound-force hydraulic cylinders were used to simulate the thrust from the Space Shuttle Main Engines. Heating and cooling simulations were conducted along with the stress tests.
In the meantime, on January 5, 1979, NASA awarded Rockwell a supplemental contract to modify STA-099 into a space-rated orbiter (OV-099), and followed this on January 29, 1979, with an order to construct two additional vehicles (OV-103 and OV-104). This $1.9 billion contract also covered modifying OV-102 following the orbital flight test series (STS-1 thru STS-4).
On February 2, 1979, the Structural Test Article officially was renamed Challenger. Like Columbia (and, indeed, the subsequent vehicles), Challenger was named for a seafaring vessel that had made a prolonged cruise from December 1872 until May 1876, gathering the equivalent of 50 volumes of information about the Atlantic and Pacific Oceans. Later, the name’s proud heritage continued when the Apollo 17 crew chose it for their lunar module in December 1972.
Testing was completed successfully and Challenger was returned to Rockwell on November 7, 1979, for conversion into OV-099. This conversion, while easier than it would have been to convert Enterprise, still involved a major disassembly of the vehicle. Within a month of arriving back from Lockheed, the payload bay doors, elevons and body flap had been removed so they could be returned to the original vendors for modifications. By January 18, 1980, the vertical stabilizer had been removed and shipped back to Fairchild-Republic in New York for rework.
Challenger had been built with a simulated crew module (which had arrived at Palmdale on January 28, 1977), and the forward fuselage halves had to be separated to gain access to the crew module. This had occurred on February 1981, and the upper forward fuselage was subsequently sent to Downey for rework. The construction of a space-worthy crew module design had already started with long-lead fabrication on January 2, 1979. This had been followed by the start of crew module assembly on June 21, 1979, followed by installation of initial systems on November 3, 1980. On July 14, 1981, the crew module arrived at Palmdale for integration into the vehicle structure. The lower fuselage was modified in Palmdale. The entire aft fuselage was removed and sent to Downey for modifications, returning to Palmdale on July 21, 1981.
On October 15, 1976, the mid-fuselage for STA-099 had arrived at Palmdale for integration with the rest of the vehicle’s components. Following the structural test program, preparations for the modifications to the mid-fuselage were begun on January 28, 1980. On May 26, 1977, the aft payload bay doors for STA-099 had arrived at Palmdale, followed by the forward doors on July 22. On December 7, 1979, after completion of the STA program, the doors were demated from Challenger for rework to orbital certification. By January 25, 1980, the doors had arrived at Rockwell, Tulsa, for rework operations, and were delivered for configuration on Challenger on July 10, 1981.
The final assembly of the vertical tail had begun on October 1, 1976, the structure being delivered on dock at Palmdale on April 6, 1977. It had been mated to STA-099 on September 30, 1977, and, after the structural test program, was demated and delivered back to Fairchild, New York, on January 18, 1980, for rework. It was on dock at Palmdale again on March 26, 1981, for mating to Challenger.
The body flap for Challenger had arrived on dock at Palmdale on May 31, 1977, and after the STA program was demated by December 14, 1979, for rework, returning to Downey on January 25, 1980. On September 1, 1980, modifications to the body flap were begun. The modifications were completed by July 17 and the unit was placed on dock at Palmdale on July 24, 1981, for final installation activities.
The final assembly of the original STA-099 wings had begun at the prime contractor on October 1, 1976, and the units had arrived on dock at Palmdale on March 16, 1977. Following the completion of the STA program, the elevons were demated on December 21, 1979 and returned to the prime contractor for rework on February 1, 1980. Three days later the preparations for the wing modifications were started, this part of the program being completed by November 21 of the same year. By March 30, 1981, the rework on the elevons had been completed at Palmdale, and these units were installed on Challenger’s wings.
Additionally the wings were modified to incorporate lessons learned from the static testing. Part of the new loads data base analysis also allowed Rockwell to relax the requirements for the wing design on OV-103 and OV-104 in order to achieve a slight weight reduction. Challenger would end up some 2,486 pounds lighter than Columbia, in spite of having additional operational equipment installed, including two heads-up displays in the cockpit.
On November 7, 1977, the Forward Reaction Control System (FRCS) for STA-099 had arrived on dock at Palmdale, and was demated by February 8, 1980, following completion of the STA program. By March 21, 1980, the forward RCS had arrived at Downey for rework to flight standard. On February 2, 1981, installation of the system components started, the package finally arriving at Palmdale on January 31, 1982, for installation in Challenger.
The first set of OMS pods for Challenger arrived early in 1982 at Palmdale for installation of the TPS. The right-hand pod was delivered on February 15, and the left-hand pod on March 3. Following this activity the pods were transported to KSC on September 3, 1982, for installation on Challenger for its first mission.
By October 23, 1981, the airframe had been modified to flight standard, and on October 26 the initial series of powered subsystems tests was started. An unpowered subsystems test was begun on November 2, and by January 29, 1982, the initial subsystems tests series had been completed. On April 16 the Challenger’s subsystems were cleared for operational use, and on April 30, 1982, the final acceptance test was completed at the Palmdale plant. In June 1982 Challenger received her final certifications before delivery. On June 4 the post-checkout operations were successfully completed, as was the configuration inspection 17 days later.
Challenger had been built with a simulated crew module (which had arrived at Palmdale on January 28, 1977), and the forward fuselage halves had to be separated to gain access to the crew module. This had occurred on February 1981, and the upper forward fuselage was subsequently sent to Downey for rework. The construction of a space-worthy crew module design had already started with long-lead fabrication on January 2, 1979. This had been followed by the start of crew module assembly on June 21, 1979, followed by installation of initial systems on November 3, 1980. On July 14, 1981, the crew module arrived at Palmdale for integration into the vehicle structure. The lower fuselage was modified in Palmdale. The entire aft fuselage was removed and sent to Downey for modifications, returning to Palmdale on July 21, 1981.
On October 15, 1976, the mid-fuselage for STA-099 had arrived at Palmdale for integration with the rest of the vehicle’s components. Following the structural test program, preparations for the modifications to the mid-fuselage were begun on January 28, 1980. On May 26, 1977, the aft payload bay doors for STA-099 had arrived at Palmdale, followed by the forward doors on July 22. On December 7, 1979, after completion of the STA program, the doors were demated from Challenger for rework to orbital certification. By January 25, 1980, the doors had arrived at Rockwell, Tulsa, for rework operations, and were delivered for configuration on Challenger on July 10, 1981.
The final assembly of the vertical tail had begun on October 1, 1976, the structure being delivered on dock at Palmdale on April 6, 1977. It had been mated to STA-099 on September 30, 1977, and, after the structural test program, was demated and delivered back to Fairchild, New York, on January 18, 1980, for rework. It was on dock at Palmdale again on March 26, 1981, for mating to Challenger.
The body flap for Challenger had arrived on dock at Palmdale on May 31, 1977, and after the STA program was demated by December 14, 1979, for rework, returning to Downey on January 25, 1980. On September 1, 1980, modifications to the body flap were begun. The modifications were completed by July 17 and the unit was placed on dock at Palmdale on July 24, 1981, for final installation activities.
The final assembly of the original STA-099 wings had begun at the prime contractor on October 1, 1976, and the units had arrived on dock at Palmdale on March 16, 1977. Following the completion of the STA program, the elevons were demated on December 21, 1979 and returned to the prime contractor for rework on February 1, 1980. Three days later the preparations for the wing modifications were started, this part of the program being completed by November 21 of the same year. By March 30, 1981, the rework on the elevons had been completed at Palmdale, and these units were installed on Challenger’s wings.
Additionally the wings were modified to incorporate lessons learned from the static testing. Part of the new loads data base analysis also allowed Rockwell to relax the requirements for the wing design on OV-103 and OV-104 in order to achieve a slight weight reduction. Challenger would end up some 2,486 pounds lighter than Columbia, in spite of having additional operational equipment installed, including two heads-up displays in the cockpit.
On November 7, 1977, the Forward Reaction Control System (FRCS) for STA-099 had arrived on dock at Palmdale, and was demated by February 8, 1980, following completion of the STA program. By March 21, 1980, the forward RCS had arrived at Downey for rework to flight standard. On February 2, 1981, installation of the system components started, the package finally arriving at Palmdale on January 31, 1982, for installation in Challenger.
The first set of OMS pods for Challenger arrived early in 1982 at Palmdale for installation of the TPS. The right-hand pod was delivered on February 15, and the left-hand pod on March 3. Following this activity the pods were transported to KSC on September 3, 1982, for installation on Challenger for its first mission.
By October 23, 1981, the airframe had been modified to flight standard, and on October 26 the initial series of powered subsystems tests was started. An unpowered subsystems test was begun on November 2, and by January 29, 1982, the initial subsystems tests series had been completed. On April 16 the Challenger’s subsystems were cleared for operational use, and on April 30, 1982, the final acceptance test was completed at the Palmdale plant. In June 1982 Challenger received her final certifications before delivery. On June 4 the post-checkout operations were successfully completed, as was the configuration inspection 17 days later.
On June 30, 1982, the vehicle was officially rolled out of the Palmdale facility, completing more than 7 1/2 years work, so bringing it up to operational standard as the second flight vehicle. On July 1, 1982, as her sister ship Columbia was orbiting the Earth during the fourth flight day of the fourth shuttle mission, Challenger was transported by road in a 38-mile journey from the Palmdale plant to Edwards Air Force Base for attachment to the Shuttle Carrier Aircraft for its journey to KSC.
Challenger was the first orbiter delivered with a name on the upper right wing and the “USA” and American flag on the left. The new stylized NASA logo and the name Challenger appeared on the right wing. The name of the vehicle was also positioned beneath the cockpit windows on the side of the forward fuselage, which remained visible with payload bay doors open for on-orbit identification.
Shortly after Columbia STS-4 landed at Edwards AFB, completing the fourth flight of the program and its OFT series, Challenger was sent on its way to KSC by President Reagan, the vehicle taking to the air for the first time on the USA’s 206th birthday, July 4, 1982. Literally millions first saw Challenger when, atop the 747 Shuttle Carrier Aircraft, the orbiter’s right wing was dipped during a nationally televised low-pass salute to President and Mrs. Reagan at Edwards Air Force Base.
The SCA flew to Florida in two stages, taking the orbiter to Ellington Field, Texas, for an overnight stop and finally, on July 5, from Ellington Field to Kennedy Space Center, Florida. Following demate from the SCA Challenger was moved to the OPF to begin final preparations for its first flight on STS-6 early in 1983.
Challenger was the first orbiter delivered with a name on the upper right wing and the “USA” and American flag on the left. The new stylized NASA logo and the name Challenger appeared on the right wing. The name of the vehicle was also positioned beneath the cockpit windows on the side of the forward fuselage, which remained visible with payload bay doors open for on-orbit identification.
Shortly after Columbia STS-4 landed at Edwards AFB, completing the fourth flight of the program and its OFT series, Challenger was sent on its way to KSC by President Reagan, the vehicle taking to the air for the first time on the USA’s 206th birthday, July 4, 1982. Literally millions first saw Challenger when, atop the 747 Shuttle Carrier Aircraft, the orbiter’s right wing was dipped during a nationally televised low-pass salute to President and Mrs. Reagan at Edwards Air Force Base.
The SCA flew to Florida in two stages, taking the orbiter to Ellington Field, Texas, for an overnight stop and finally, on July 5, from Ellington Field to Kennedy Space Center, Florida. Following demate from the SCA Challenger was moved to the OPF to begin final preparations for its first flight on STS-6 early in 1983.
Challenger is the first “operational” shuttle spacecraft. All of its onboard systems have qualified to operate for a minimum of 100 missions without major overhaul. Although Columbia, on its STS-5 flight, was billed as the first operational mission, the onboard systems do not have operational certification. Following the STS-9 mission later in 1983, Columbia will be scheduled to return to Rockwell’s Palmdale plant for major modification, which includes installation of operational systems.
Each new spacecraft to come off the assembly bays in the orbiter manufacturing facility at Palmdale carries improvements in structure, materials and equipment that are not apparent to the observer. Challenger weighs 1,128 kg (2,486 lb.) less than Columbia as a result of weight-saving structural changes that include use of lightweight honeycomb for such things as landing gear doors and vertical tail tip and leading edge.
Much of the secondary support structure in the aft fuselage around the main engine thrust frames has been eliminated or combined with the primary structure. The main engine heatshields are lighter, and in the mid-fuselage the titanium cryogenic tank supports have been replaced with tubing made of boron-aluminum. Challenger weighs 67,876 kg (149,642 lb.) "dry" while Columbia weighs 69,004 kg (152,128 lb.). Loaded with crew, cargo, consumables and experiments, during STS-6 Challenger will weigh 117,267 kg (258,529 lb.) at launch. The STS-6 vehicle, with lightweight External Tank and Solid Rocket Booster casings, will weigh 2,036,856 kg (4,490,498 lb.) at SRB ignition, just 880 kg (1,939 lb.) more than the STS-5 vehicle at launch.
Advanced Flexible Reusable Surface Insulation (AFRSI) blankets, consisting of sewn composite quilted fabric blanket with the same silica tile material sandwiched between outer and inner blanket, have replaced more than 600 Low-temperature Reusable Surface Insulation (LRSI) glass tiles over the two Orbital Maneuvering System pods and the Reaction Control System. AFRSI sheets do not require Thermal protection system silica glass tiles over the rest of Challenger's skin have been densified for improved bonding, based on the lesson learned from Columbia's early tile problems. All 30,000 tiles have been specially treated (densified) to improve their durability.
The Challenger main engines, numbers 2012, 2015 and 2017, will deliver 104 percent of rated thrust, a higher thrust level than the engines on Columbia, which were operated at 100 percent. For each percent increase of thrust over 100 percent, the shuttle gains 454 kg (1,000 lb.) of payload carrying capability.
This higher thrust level was accomplished by incorporating redesigned engine parts into the original engine design. The changes were necessary because of higher temperatures, pressures and pump speeds that the new engines will encounter at the higher thrust level. All the changes were proved out in a very intense engine testing program, which included more than 62,000 seconds of engine firings.
Significant engine changes include: use of higher strength liquid oxygen posts in the main injector due to higher temperatures and pressures; use of a modified fuel pre-burner because of previous erosion of turbine blades and thermal shield nut erosion; and using thicker tubes and redesigning coolant supply lines in the nozzle to accommodate high loads at ignition. The test program and manufacture of the main engines is carried out by the Rocketdyne Division of Rockwell International under the direction of the NASA Marshall Space Flight Center, Huntsville, Alabama.
Each new spacecraft to come off the assembly bays in the orbiter manufacturing facility at Palmdale carries improvements in structure, materials and equipment that are not apparent to the observer. Challenger weighs 1,128 kg (2,486 lb.) less than Columbia as a result of weight-saving structural changes that include use of lightweight honeycomb for such things as landing gear doors and vertical tail tip and leading edge.
Much of the secondary support structure in the aft fuselage around the main engine thrust frames has been eliminated or combined with the primary structure. The main engine heatshields are lighter, and in the mid-fuselage the titanium cryogenic tank supports have been replaced with tubing made of boron-aluminum. Challenger weighs 67,876 kg (149,642 lb.) "dry" while Columbia weighs 69,004 kg (152,128 lb.). Loaded with crew, cargo, consumables and experiments, during STS-6 Challenger will weigh 117,267 kg (258,529 lb.) at launch. The STS-6 vehicle, with lightweight External Tank and Solid Rocket Booster casings, will weigh 2,036,856 kg (4,490,498 lb.) at SRB ignition, just 880 kg (1,939 lb.) more than the STS-5 vehicle at launch.
Advanced Flexible Reusable Surface Insulation (AFRSI) blankets, consisting of sewn composite quilted fabric blanket with the same silica tile material sandwiched between outer and inner blanket, have replaced more than 600 Low-temperature Reusable Surface Insulation (LRSI) glass tiles over the two Orbital Maneuvering System pods and the Reaction Control System. AFRSI sheets do not require Thermal protection system silica glass tiles over the rest of Challenger's skin have been densified for improved bonding, based on the lesson learned from Columbia's early tile problems. All 30,000 tiles have been specially treated (densified) to improve their durability.
The Challenger main engines, numbers 2012, 2015 and 2017, will deliver 104 percent of rated thrust, a higher thrust level than the engines on Columbia, which were operated at 100 percent. For each percent increase of thrust over 100 percent, the shuttle gains 454 kg (1,000 lb.) of payload carrying capability.
This higher thrust level was accomplished by incorporating redesigned engine parts into the original engine design. The changes were necessary because of higher temperatures, pressures and pump speeds that the new engines will encounter at the higher thrust level. All the changes were proved out in a very intense engine testing program, which included more than 62,000 seconds of engine firings.
Significant engine changes include: use of higher strength liquid oxygen posts in the main injector due to higher temperatures and pressures; use of a modified fuel pre-burner because of previous erosion of turbine blades and thermal shield nut erosion; and using thicker tubes and redesigning coolant supply lines in the nozzle to accommodate high loads at ignition. The test program and manufacture of the main engines is carried out by the Rocketdyne Division of Rockwell International under the direction of the NASA Marshall Space Flight Center, Huntsville, Alabama.
In September 1979 the NASA directed Rockwell International’s Shuttle Orbiter Division to add a heads-up display (HUD) system to the shuttle orbiter. This was the result of approximately two years of study activity by NASA and Rockwell with the support of several HUD subcontractors. Rockwell awarded a letter contract to Kaiser Electronics, San Jose, California, in June 1980 to provide a HUD system for the orbiter. The program was progressing on schedule and a pre-production hardware set was delivered to Rockwell in November 1980 for use in the Avionics Development Laboratory for preliminary interface testing.
A heads-up system allows an out-of-the-window view while providing flight commands and information to the flight crew by superimposing this information on a transparent combiner in the out-the-window field of view. The baseline orbiter, like most commercial aircraft, utilizes conventional electromechanical displays on a display panel beneath the glare shield which necessitates that the flight crew look down for information and then up for out-the-window information. During critical flight phases, in particular the approach and landing case, this is not an easy task. In the orbiter with its unique vehicle dynamics and approach trajectories, this situation is even more critical.
Since the orbiter is intended to be in service for several years, it was considered appropriate that it be equipped with this system. In the study phase it was determined that most recent military aircraft include HUD systems and that the airliners used by several European countries also contain HUD’s. Additionally, it was apparent that the display portion of some existing HUD systems would lend themselves to modification for installation in the orbiter. So as to minimize development costs, the HUD system requirements for the orbiter were patterned after existing hardware.
While the display portion of the orbiter system could be similar to existing HUD systems, the drive electronics could not. The orbiter avionics is digital and since minimal impact to the spacecraft was paramount, the HID drive electronics were designed to receive data from the orbiter data buses. Most existing HUD drive electronics use analog data or a combination analog/digital interface. In the orbiter system, the HUD drive electronics utilizes to the maximum extent possible the same data which drives the existing electromechanical display devices to minimize impact to the existing software.
The orbiter display device as designed by Kaiser Electronics uses a Cathode Ray Tube (CRT) to create the image which is then projected through a series of lenses on a combining glass which is very similar to a system they developed and produced for the Cobra Jet Aircraft. Certain orbiter design requirements, including vertical viewing angles, brightness and unique mounting requirements, dictated some changes from the Cobra Jet configuration.
On the orbiter, the HUD will be installed at each flight station (CDR and PLT). Each HUD system is single string although connected to two data buses; redundancy is achieved by the fact that a system is installed at each station (similar to the redundancy system used for present displays), and the fact that the already existing displays can be used in the event of one HUD failure.
The HUD system, which will first be used aboard OV-099 Challenger, is to be installed in line in the production flow for OV-103 and OV-104. It is planned to build a kit which supports installation of the HUD on OV-102. In addition, several other systems are being built for test sites and simulators. A new improved display format is being developed for the heads-up display which will further reduce the CDR/PLT workload during approach and landing. This improved format will be implemented on future Space Shuttle missions.
The HUD is an excellent landing aid and is considered the primary pilot display during this phase. As the system matures, it is anticipated that the HUD will be used for star/land mark sightings as well as rendezvous with other orbiting vehicles, space platforms, etc.
A heads-up system allows an out-of-the-window view while providing flight commands and information to the flight crew by superimposing this information on a transparent combiner in the out-the-window field of view. The baseline orbiter, like most commercial aircraft, utilizes conventional electromechanical displays on a display panel beneath the glare shield which necessitates that the flight crew look down for information and then up for out-the-window information. During critical flight phases, in particular the approach and landing case, this is not an easy task. In the orbiter with its unique vehicle dynamics and approach trajectories, this situation is even more critical.
Since the orbiter is intended to be in service for several years, it was considered appropriate that it be equipped with this system. In the study phase it was determined that most recent military aircraft include HUD systems and that the airliners used by several European countries also contain HUD’s. Additionally, it was apparent that the display portion of some existing HUD systems would lend themselves to modification for installation in the orbiter. So as to minimize development costs, the HUD system requirements for the orbiter were patterned after existing hardware.
While the display portion of the orbiter system could be similar to existing HUD systems, the drive electronics could not. The orbiter avionics is digital and since minimal impact to the spacecraft was paramount, the HID drive electronics were designed to receive data from the orbiter data buses. Most existing HUD drive electronics use analog data or a combination analog/digital interface. In the orbiter system, the HUD drive electronics utilizes to the maximum extent possible the same data which drives the existing electromechanical display devices to minimize impact to the existing software.
The orbiter display device as designed by Kaiser Electronics uses a Cathode Ray Tube (CRT) to create the image which is then projected through a series of lenses on a combining glass which is very similar to a system they developed and produced for the Cobra Jet Aircraft. Certain orbiter design requirements, including vertical viewing angles, brightness and unique mounting requirements, dictated some changes from the Cobra Jet configuration.
On the orbiter, the HUD will be installed at each flight station (CDR and PLT). Each HUD system is single string although connected to two data buses; redundancy is achieved by the fact that a system is installed at each station (similar to the redundancy system used for present displays), and the fact that the already existing displays can be used in the event of one HUD failure.
The HUD system, which will first be used aboard OV-099 Challenger, is to be installed in line in the production flow for OV-103 and OV-104. It is planned to build a kit which supports installation of the HUD on OV-102. In addition, several other systems are being built for test sites and simulators. A new improved display format is being developed for the heads-up display which will further reduce the CDR/PLT workload during approach and landing. This improved format will be implemented on future Space Shuttle missions.
The HUD is an excellent landing aid and is considered the primary pilot display during this phase. As the system matures, it is anticipated that the HUD will be used for star/land mark sightings as well as rendezvous with other orbiting vehicles, space platforms, etc.
A new, lighter-weight motor case has been developed for the Space Shuttle's Solid Rocket Boosters which will increase the shuttle's weight carrying capability by about 363 kg (800 lb.). Weights may vary slightly for each mission. Each booster's motor case used on STS-6 and future flights will weigh about 44,452 kg (98,000 lb.) which is approximately 1,814 kg (4,000 lb.) less than those flown on previous shuttle flights. The weight reduction was achieved by reducing the thickness of the casings' steel skin about two-hundredths to four-hundredths of an inch. Areas of the cases affected by the reduction are the cylindricals attach and stiffener segments.
The thinner casings of the motors will not affect their reusability. Also, the lighter case segments will be interchangeable with the heavier cases flown on previous shuttle flights. The motor cases for the boosters are manufactured by the Rohr Corp. for the motor prime contractor, the Wasatch Division of Morton Thiokol Corp., Brigham City, Utah, under the direction of Marshall Space Flight Center.
Beginning with the External Tank built for use on STS-6, all future tanks will be more than 4,536 kg (10,000 lb.) lighter than the tank which flew on the Space Shuttle's maiden flight in April 1981. Although, the weight of each future tank may vary slightly, each will weigh about 30,390 kg (67,000 lb.). The advantage of using a lighter weight tank is that for each pound of weight reduced from the tank, the shuttle gains almost an extra pound of cargo carrying capability.
The weight reduction was accomplished by eliminating portions of stringers (structural stiffeners running the length of the hydrogen tank), using fewer stiffener rings and by modifying major frames in the hydrogen tank. Also, significant portions of the tank are milled differently to reduce thickness, and the weight of the tank's aft Solid Rocket Booster attachments was reduced by using a stronger, yet lighter and less expensive titanium alloy.
Several hundred pounds were eliminated earlier by deleting an antigeyser line. The STS-5 tank was the first flown with this modification. Development is continuing to further reduce the weight of future tanks.
The External Tank is actually made up of two tanks and a collar-like intertank which connects the two. The two individual tanks carry the liquid hydrogen and liquid oxygen for the Space Shuttle's three main engines. Total length and diameter of the tank remains unchanged due to the weight reduction. The final 34,927 kg (77,000 lb.) tank, which was manufactured earlier than the lighter-weight tank used for STS-6, will be flown on STS-7. The tanks are manufactured by the Michoud Division of Martin Marietta Aerospace, near New Orleans, under the direction of Marshall Space Flight Center.
The thinner casings of the motors will not affect their reusability. Also, the lighter case segments will be interchangeable with the heavier cases flown on previous shuttle flights. The motor cases for the boosters are manufactured by the Rohr Corp. for the motor prime contractor, the Wasatch Division of Morton Thiokol Corp., Brigham City, Utah, under the direction of Marshall Space Flight Center.
Beginning with the External Tank built for use on STS-6, all future tanks will be more than 4,536 kg (10,000 lb.) lighter than the tank which flew on the Space Shuttle's maiden flight in April 1981. Although, the weight of each future tank may vary slightly, each will weigh about 30,390 kg (67,000 lb.). The advantage of using a lighter weight tank is that for each pound of weight reduced from the tank, the shuttle gains almost an extra pound of cargo carrying capability.
The weight reduction was accomplished by eliminating portions of stringers (structural stiffeners running the length of the hydrogen tank), using fewer stiffener rings and by modifying major frames in the hydrogen tank. Also, significant portions of the tank are milled differently to reduce thickness, and the weight of the tank's aft Solid Rocket Booster attachments was reduced by using a stronger, yet lighter and less expensive titanium alloy.
Several hundred pounds were eliminated earlier by deleting an antigeyser line. The STS-5 tank was the first flown with this modification. Development is continuing to further reduce the weight of future tanks.
The External Tank is actually made up of two tanks and a collar-like intertank which connects the two. The two individual tanks carry the liquid hydrogen and liquid oxygen for the Space Shuttle's three main engines. Total length and diameter of the tank remains unchanged due to the weight reduction. The final 34,927 kg (77,000 lb.) tank, which was manufactured earlier than the lighter-weight tank used for STS-6, will be flown on STS-7. The tanks are manufactured by the Michoud Division of Martin Marietta Aerospace, near New Orleans, under the direction of Marshall Space Flight Center.
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