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.
No comments:
Post a Comment