STS-75
Columbia
Tethered Satellite System-1R (TSS-1R)
United States Microgravity Payload-3 (USMP-3)

KSC Release No. 5-96
February 1996
Aqui esta la version para la Mision STS-75 Fact Sheet en Espanol.
The seven-member international STS-75 crew will conduct scientific investigations with both the Tethered Satellite System-1R (TSS-1R) and United States Microgravity Payload-3 (USMP-3) primary payloads during the 75th Space Shuttle mission. The 13-day, 16- hour space flight will begin when the Space Shuttle Orbiter Columbia lifts off from Launch Pad 39B and climbs to a 184-statute-mile-high orbit with a 28.45- degree inclination to the Earth’s equator.

Once in orbit, the 5-foot (1.6 meter)-in-diameter TSS- 1R satellite will be deployed from its pallet in Columbia’s payload bay to a distance of 12.4 miles (20.7 kilometers) above the orbiter as an attached, electrically-conductive tether the diameter of a wooden matchstick unwinds from a motorized reel. After the TSS-1R investigations and retrieval of the satellite, the crew will conduct research with four major USMP-3 experiment packages in Columbia’s payload bay and three combustion experiments in a Glovebox facility located in the orbiter’s middeck area.

The STS-75 mission is scheduled to end with Columbia’s touchdown at the KSC Shuttle Landing Facility.

The Crew
The STS-75 crew includes two European Space Agency (ESA) astronauts and one from the Italian Space Agency (ASI), as well as four veterans of STS-46, the first TSS-1 mission.

Mission Commander Andrew M. Allen (Major, USMC) is on his third space flight, having served as pilot of both STS-62 and STS-46. The Pilot is Scott J. "Doc" Horowitz (Ph.D.) (Major, USAF), who is on his first Shuttle mission. Payload Commander Franklin R. Chang-Diaz (Ph.D.) has flown on STS-60, STS-46, STS-34, and STS 61-C. Mission Specialist Jeffrey A. Hoffman (Ph.D.) has served in this capacity on STS 61, STS-46, STS-35 and STS 51-D.Mission Specialist Claude Nicollier (ESA) has flown on both STS-61 and STS-46. Mission Specialist Maurizio Cheli (ESA) is a lieutenant colonel in the Italian Air Force. Payload Specialist Umberto Guidoni (ASI) is the project scientist responsible for the integration of the Electrodynamic Tether Effects (RETE) experiment on the TSS-1R.

The TSS-1R Mission
The TSS program is a joint venture between ASI and NASA. Its objectives on this flight are to demonstrate the ability to deploy and control satellites on long tethers in space and to conduct space plasma experiments that include the generation of electrical power. The TSS-1 first flew on STS-46 in 1992, but a mechanical problem allowed the satellite to be deployed only to height of 840 feet. The "R" designation indicates a reflight of the same payload with modifications.

The primary TSS-1R components are the 1,141- pound (518-kilogram) satellite, its deployer system mounted on a Spacelab pallet in the orbiter payload bay and the Spacelab Mission Peculiar Equipment Support Structure (MPESS) that holds the three- orbiter-based science instruments to be used in TSS-1R experiments. The satellite carries an additional four instruments. This sphere has an aluminum alloy skin that is electrically conductive, three instrument sensor booms, a payload module for the science instruments and a service module that contains telemetry, power distribution, data handling and navigational equipment. The middle section contains a gaseous nitrogen tank that will fuel the 12 low-powered thrusters that will propel the satellite during deployment above the orbiter.

Deployment, Experiments and Retrieval
On Flight Day 3, the crew will begin deployment by raising a 40-foot (12-meter) deployment boom that elevates the satellite and its support structure to this height. Once released, the satellite will climb upward from the orbiter and away from Earth, aided by gravitational force and the use of its onboard thrusters, to attain a distance of 12.4 miles (20.7 kilometers) over a 5-1/2 hour period. The crew will control the satellite and deployer system from the aft flight deck.

The attached tether, with a diameter of 0.1 inches (2.5 millimeters) is made of Nomex and Kevlar. This super- strong and thin strand, also contains a tin-coated, insulated copper wire bundle that makes it electrically conductive.

As the tether passes through the electromagnetic fields of the Earth’s atmosphere, an electrical charge is expected to build up between the satellite and the orbiter through an electrodynamic process. Electrons from the ionosphere will be collected at the satellite and will travel down the tether to the orbiter. The Deployer Core Equipment (DCORE) instrument in the payload bay will control this flow of electrical current in the tether with two electron generator assemblies. The Shuttle Electrodynamic Tether System (SETS) will provide measurements of the tether voltage and current and generate an electron beam in support of science investigations. The Shuttle Potential and Return Electron Experiment (SPREE) will measure ion and electron distribution and determine the orbiter electrical potential. Other investigations will study the effects of the deployed tether and satellite on the space environment.

Approximately 27 hours after deployment, the crew will activate the 5-horsepower electric motor that will rewind the tether and draw the satellite back to the top of the satellite support structure in the payload bay. The retrieval will be conducted in two phases over a period of 18 hours.

USMP-3 Experiments
Payload bay --The USMP-3 payload is designed to gather data that will continue NASA’s microgravity research program to provide advances in the fields of materials science and condensed matter physics. Two MPESSs located in Columbia’s payload bay will serve as the platforms for the five USMP-3 experiments in Columbia’s payload bay.

The Advanced Automated Directional Solidification Furnace (AADSF) will use lead tin telluride semiconductor alloy samples in the study of a common method of processing semiconductors known as direc- tional solidification. A better understanding of this process could lead to improved production methods on Earth.

The Critical Fluid Light Scattering Experiment, or ZENO, will analyze Xenon fluid at the "critical point", a phase where liquid changes to vapor. Understanding how matter behaves at this point could lead to advances in physics.

By investigating the physical process of convection in space, the MEPHISTO experiment could lead to improvements to materials preparation and processing during their manufacture on Earth. The Isothermal Dendritic Growth Experiment (IDGE) could also lead to the production of improved manufacturing processes by studying how dendritic crystals formed during solidification affect the strength and durability of metals. The Space Acceleration and Measurement System (SAMS) supports USMP-3 experiments by making accurate measurements of residual orbiter accelerations and vibrations that can affect these investigations. The Orbital Acceleration Research Experiment (OARE) will help USMP-3 scientists predict how microgravity conditions in space can influence their experiments.

Middeck experiments -- Three middeck experiments will study the characteristic of fires and how they spread in microgravity. The data from this work will be used to help design safer spacecraft and better fire detection systems on Earth.

KSC Payload Processing
The TSS-1 payload was returned to KSC at the end of the STS-46 mission and underwent the TSS Contingency Investigation in the Operations and Checkout (O&C) Building to determine the cause of the tether reel system malfunction during that space flight. Modifications were made to the system and processing began for its reflight on the STS-75 mission.

Integration of the USMP-3 payload began in 1995 and final checkout work was completed in December of that year. Both the TSS-1R and the USMP-3 were then transported to Launch Pad 39B for integration into Columbia’s payload bay on Jan 31, 1996. Columbia was rolled out to Pad 39B on Jan. 29.

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