With the Spartan solar science satellite again secured in its berth in Discovery's payload bay, the astronauts will turn their full attention to some of the more than 80 experiments on board. They also will begin shutting down some of the experiments and facilities in anticipation of their return to Earth on Saturday morning.
Mission Specialist Steve Robinson will power up the Orbiter Space Vision System (OSVS) for an image optimization test. OSVS will be used in International Space Station assembly as a key source of precision data with which the robot arm operator will perform station assembly activities. Robinson and European Space Agency Mission Specialist Pedro Duque also will power up the Extravehicular Mobility Unit (EMU) and check the unit's communications system. The EMU would be used should a spacewalk become necessary; it provides pressure, thermal and micro-meteoroid protection, oxygen, cooling water, drinking water, food, waste collection (including carbon dioxide removal), electrical power and communications.
As they have throughout the flight, Commander Curt Brown, Pilot Steve Lindsey, Mission Specialist Steve Robinson and Payload Specialist John Glenn will complete a back-pain questionnaire as part of a study of how the muscle, intervertebral discs and bone marrow change due to microgravity. Results will be compared with data provided by astronauts during previous missions.
Glenn will continue blood sample analysis and blood processing that are part of the Protein Turnover (PTO) experiment, which is studying the muscle loss that occurs during space flight. Better understanding of the mechanisms of muscle loss may help scientists combat the muscle wasting commonly seen as a result of aging and in bedridden individuals.
Deactivation of some of the experiments will begin today. After using the Electronic Nose one last time to test the shuttle's air quality, Brown will deactivate it for the duration of the mission. The Electronic Nose is a miniaturized electronic air quality monitoring system that mimics the way the human nose detects changes in the air. Duque also will do a final shutdown of the Microgravity Science Glovebox and stow equipment associated with the facility.
Mission Specialist Scott Parazynski will check on the fish in the Vestibular Function Experiment Unit (VFEU). By studying how the balance organs of oyster toadfish in the VFEU adapt to microgravity, scientists hope to gain important insights about similar functions in humans and apply this information to develop therapies for equilibrium disorders on Earth.
At 12:10 p.m. Central time, the entire crew will gather for a press conference with U.S. and Japanese reporters at the Johnson Space Center in Houston, as well as with reporters gathered at the European Space Agency's Villafranca tracking facility outside Madrid, Spain. At 2:40 p.m. Central time, the astronauts will gather again for a conversation with Vice-President Al Gore and former Mercury astronaut Scott Carpenter from the White House.
Before going to sleep Wednesday night, the entire crew will gather for the traditional crew photograph. Then Glenn and Japanese Payload Specialist Chiaki Mukai will don for the last time their sleep nets and suits to monitor brain waves, eye movements, muscle tension, body movements and respiration during sleep. Mukai also will swallow a capsule containing either melatonin or a placebo as part of the sleep study.
Lindsey and Mukai will conduct additional work with the Astroculture experiment to study the growth of plants in the weightless environment of space. Brown and Glenn will complete the eighth and ninth feedings of the bone cell cultures that are part of the Canadian OSTEO experiment.
Preliminary weather forecasts indicate generally favorable weather to support Saturday's landing at 11:10 a.m. Central time at the Kennedy Space Center. Remnants of tropical storm Mitch are expected to pass through the area and move off Florida's east coast Friday night, allowing good weather for landing on Saturday.
Discovery is orbiting the Earth every 95 minutes at an altitude of about 341 statute miles with all systems operating in excellent condition.