During the 10 day mission, the Space Radar Laboratory (SRL) payload in Endeavour's cargo bay will make its second flight. The SRL payload, which first flew during STS-59 in April 1994, will again give ... scientists highly detailed information that will help them distinguish between human-induced environmental changes and other natural forms of change.
SRL-2 will take radar images of the Earth's surface for Earth system sciences studies, including geology, geography, hydrology, oceanography, agronomy and botany.
The SRL payload is comprised of the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR), and the Measurement of Air Pollution from Satellite (MAPS). The German Space Agency (DARA) and the Italian Space Agency (ASI) are providing the X-SAR instrument.
The imaging radar of the SIR-C/X-SAR instruments has the ability to make measurements over virtually any region at any time, regardless of weather or sunlight conditions. The radar waves can penetrate clouds, and under certain conditions, also can "see" through vegetation, ice and extremely dry sand. In many cases, radar is the only way scientists can explore inaccessible regions of the Earth's surface.
The SIR-C/X-SAR radar data provide information about how many of Earth's complex systems - those processes that control the movement of land, water, air and life - work together to make this a livable planet. The science team particularly wants to study the amount of vegetation coverage, the extent of snow packs, wetlands areas, geologic features such as rock types and their distribution, volcanic activity, ocean wave heights and wind speed. STS-68 will fly over the same sites that STS-59 observed so that scientists will be able to study seasonal changes that may have occurred in those areas between the missions.
An international team of 49 science investigators and three associates will conduct the SIR-C/X-SAR experiments. Thirteen nations are represented: Australia, Austria, Brazil, Canada, China, the United Kingdom, France, Germany, Italy, Japan, Mexico, Saudi Arabia and the United States. The MAPS experiment will measure the global distribution of carbon monoxide in the troposphere, or lower atmosphere. Measurements of carbon monoxide, an important element in several chemical cycles, provide scientists with indications of how well the atmosphere can cleanse itself of "greenhouse gases," chemicals that can increase the atmosphere's temperature.
STS-68 provided a continuation of NASA's Get Away Special (GAS) experiments program. The project gives a person or organization a chance to perform experiments in space on a Shuttle mission. Two universities, North Carolina A&T State University and University of Alabama in Huntsville, and the Swedish Space Corp., Soina, Sweden, will have small self-contained payloads flying during the STS-68 mission. Other GAS hardware in Endeavour's payload bay will carry 500,000 commemorative stamps for the U.S. Postal Service in recognition of the 25th anniversary of the Apollo 11 Moon landing.
Other payloads aboard Endeavour include the Biological Research in Canister (BRIC) which will fly for the first time, and the Military Applications of Ship Tracks (MAST) which will be making its second flight. BRIC experiments, sponsored by NASA's Office of Life and Microgravity Sciences and Applications, are designed to examine the effects of microgravity on a wide range of physiological processes in higher order plants and arthropod animals (e.g., insects, spiders, centipedes, crustaceans). MAST is an experiment sponsored by the Office of Naval Research (ONR) and is part of a five-year research program developed by ONR to examine the effects of ships on the marine environment.
The Commercial Protein Crystal Growth (CPCG) experiment, the Chromosome and Plant Cell Division in Space Experiment (CHROMEX) and the Cosmic Radiation Effects and Activation Monitor (CREAM) experiment also will be carried aboard Endeavour.
[Summary provided by NASA]