Ed Campion Headquarters, Washington, D.C. January 6, 1993 (Phone: 202/453-8536) RELEASE: 93-004 FIRST 1993 SHUTTLE MISSION DEMONSTATES UNIQUE CAPABILITIES The versatility of NASA's Space Shuttle system will be demonstrated next week during the first mission of 1993 when Shuttle Endeavour and her crew conduct a diverse group of experiments and tasks in Earth orbit. During the mission, a communications satellite will be deployed, x-ray astronomy observations will be taken, experiments covering a wide range of scientific disiplines will be conducted and a spacewalk to evaluate training techniques will be performed. Endeavour and her crew are scheduled to be launched on Wednesday, Jan. 13 with a launch window opening at 8:52 a.m. EST. The mission duration is approximately 6 days with landing scheduled for Tuesday, Jan. 19 at Kennedy Space Center, Fla. Crew members for the STS-54 mission are Commander John Casper, Pilot Don McMonagle and three mission specialists -- Mario Runco, Jr., Greg Harbaugh and Susan Helms. The STS-54 mission will be the third flight of Space Shuttle Endeavour and the 53rd flight of the system overall. Tracking and Data Relay Satellite System The Tracking and Data Relay Satellite System (TDRSS) is a space-based network that provides communications, tracking, telemetry, data acquisition and command services essential to the Space Shuttle and low-Earth orbital spacecraft missions. All Shuttle missions and nearly all NASA spacecraft in Earth orbit require TDRSS's capabilities for mission success. Tracking and Data Relay Satellite (TDRS-6) being deployed on the STS-54 mission is the sixth in a series of communications spacecraft planned for the TDRS system. - more - - 2 - The successful launch and checkout of TDRS-6 will give NASA the essential requirement of having two fully operational satellites and a fully operational ready reserve capability. This will assure that NASA communications, telemetry and data acquisition capabilities required by space missions will not be jeopardized. Diffuse X-ray Spectrometer The Diffuse X-ray Spectrometer (DXS) addresses a fundamental question of present-day astrophysics: What is the origin and nature of the interstellar medium -- the matter that fills the space between stars? A large percentage of x-rays from space do not originate from specific objects like stars or galaxies, but from some source that appears to be distributed over the entire sky. Astronomers have found that these emissions fall into two types: high-energy or "hard" x-rays that may be the unresolved emissions from a collection of distant galaxies and low-energy or "soft" x-rays that are not yet well understood. DXS will study the latter. Because low energy x-rays cannot travel more than a few hundred light years in interstellar space before they are absorbed, most of the diffuse soft x-ray background observed must have originated in the Milky Way galaxy from the vicinity of Earth's solar system. The DXS measures the arrival direction and wavelength of incident low energy x-rays in the wavelength range of 42 to 84 Angstroms (an Angstrom is one ten-thousandth of a millimeter). From this information, the DXS scientists will be able to determine the spectrum (brightness at each wavelength) of the diffuse soft x-ray background from each of several regions of the sky. By analyzing these spectral features, scientists can identify the temperature, the ionization state and the elements which constitute this plasma. From these data they can tell whether the plasma is young and heated in the last 100,000 years or old and heated millions of years ago. Previous experiments were not capable of measuring the spectrum of the diffuse soft X-ray background. EVA Test Objectives On the fifth day of the STS-54 flight, Mission Specialists Greg Harbaugh and Mario Runco, Jr., will perform the first in a series of test spacewalks to be conducted on Shuttle missions during the years leading up to the construction of Space Station Freedom, scheduled to begin in 1996. - more - - 3 - The spacewalk tests are designed to refine training methods for future spacewalks; expand the experience of ground controllers, instructors and astronauts; and aid in better understanding the differences between true weightlessness and the underwater facility used to train crew members. During the STS-54 spacewalk, Runco and Harbaugh will evaluate how well they respectively adapt to spacewalking; test their abilities to move about the cargo bay with and without carrying items; test the ability to climb into a foot restraint without handholds; and test their ability to align a large object in weightlessness. CHROMEX-4 Developmental and Physiological Processes Influencing Seed Production in Microgravity (CHROMEX-4) is designed to gain an understanding of the reproductive abnormalities which apparently occur in plants exposed to microgravity and to determine whether changes in developmental processes may be due to spaceflight conditions, especially microgravity. This experiment also will help scientists understand how gravity influences fertilization and development on Earth. To date, only a few studies have been conducted on developing seeds in space. They all showed very poor seed production. NASA would like to use plants as a source of food and atmospheric cleansing for astronauts staying in space for extended periods of time. Seed production is vital if crops like wheat and rice are to be utilized for food. Commercial Generic Bioprocessing Apparatus The purpose of the Commercial Generic Bioprocessing Apparatus (CGBA) is to allow a wide variety of sophisticated biomaterials, life sciences and biotechnology investigations to be performed in one apparatus in microgravity. During the STS-54 mission, the CGBA will support 28 separate commercial investigations, loosely classified in three application areas: biomedical testing and drug development, controlled ecological life support system and agricultural development and manufacture of biological-based materials. Results from the 28 investigations will be carefully considered in determining subsequent steps toward commercialization. STS-54 marks the second of six CGBA flights. Future flights will continue to focus on selecting and developing investigations that show the greatest commercial potential. - more - - 4 - Physiological and Anatomical Rodent Experiment The second Physiological and Anatomical Rodent Experiment (PARE.02) is a secondary payload flight experiment located in a locker on the Space Shuttle's mid-deck. The goal of PARE.02 is to determine the extent to which short-term exposure to microgravity alters the size, strength and stamina of skeletal muscles normally used to support the body against the force of gravity. The PARE.02 experiment is important for two reasons. When individuals are exposed to the microgravity of spaceflight, there appears to be a significant loss in muscle mass. This appears to be because the muscle must no longer exert a sufficient level of force, which produces a signal to the body to conserve mass. However, the loss of muscle mass hinders one's capability to function when returning to Earth. All movement patterns are difficult, and the individual may be prone to accidents because of this instability. Scientists need to find out the extent to which the muscle atrophies, what impact the atrophy process has on muscle performance and how to prevent the atrophy from occurring. Second, the problem of muscle atrophy is similar in part to what is seen on Earth during the normal span of aging. As one gets older, he or she becomes less physically active, and the degree of muscle disuse is exaggerated. This leads to the same problems as occur during exposure to microgravity. Thus, if the problem of atrophy in space can be solved, scientists should have good insight for maintaining the muscle system in a more viable condition as people age. Solid Surface Combustion Experiment The purpose of the Solid Surface Combustion Experiment (SSCE) is to study the physical and chemical mechanisms of flame propagation over solid fuels in the absence of gravity-driven buoyant or externally-imposed airflows. The controlling mechanisms of flame propagation in microgravity are different than in normal gravity. On Earth, gravity causes the air heated by the flame to rise. This air flow, called buoyant convection, feeds oxygen to the flame and cools the fire, creating competing effects. In microgravity, this flow is absent. Therefore, the fire is sustained only by the oxygen that it consumes as it migrates along the fuel's surface. The results of the SSCE have a practical application in the evaluation of spacecraft fire hazards, as well as providing a better understanding of flame propagation in microgravity and on Earth. - end -