STS-78 Day 13 Highlights

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On Tuesday, July 2, 1996, 6:00 a.m. CDT, STS-78 MCC Status Report # 25 reports:

Another day of scientific investigations is under way on board Columbia as the Life and Microgravity Spacelab mission enters its 13th day in orbit.

Today, the seven crew members will continue supporting a variety of experiments investigating the effects of microgravity on the human body. Studies looking at muscle strength and energy expenditure and astronaut pulmonary function will continue throughout the day, as will the processing of advanced semiconductor materials and alloys in the Advanced Gradient Heating Facility.

In an interview this morning with the NBC Newschannel, Mission Commander Tom Henricks discussed Columbia's flight and the varied experiments which are being conducted on board. Henricks explained that the crew is shifting its scheduled sleep period 25 minutes earlier with each day, in part to support an early morning wakeup call on landing day, but also as an investigation into circadian rhythms and their effect on crew performance. Crew members participate in tests which measure their performance on duty, and instrumentation worn while the crew is asleep gages the quality of sleep for the crew members.

Flight Day 13 began with a wake-up call from Mission Control at 12:30 a.m. Central time today. The crew awoke to "Closer to Free" by the Bodines.

Columbia continues to operate trouble-free as it circles the Earth once every 90 minutes at an altitude of 168 statute miles.

On Tuesday, July 2, 1996, 3:00 p.m. CDT, STS-78 Payload Status Report # 13 reports: (MET 012/05:11:00)

Four Shuttle crew members today began the second of two key 72-hour periods of the Sleep and Circadian Rhythms Study.

Mission Specialists Dr. Richard Linnehan and Dr. Charles Brady, and Payload Specialists Dr. Jean-Jacques Favier and Dr. Robert Thirsk are participating in this investigation which is the first-ever comprehensive study of sleep, 24-hour circadian rhythms and task performance in a microgravity environment. Crew members complete questionnaires before each meal, just after waking, and at the end of their shift to help monitor their alertness and mood. Just before going to sleep, they also put on sleep caps with electrodes that will help measure brain waves, eye movements and muscle activity while they sleep.

Researchers will compare information gathered during the current 72-hour period with information from the first period held June 22-24 to create a picture of how the crews' sleep patterns changed over the duration of the mission. The study's principal investigator, Dr. Timothy Monk of the University of Pittsburgh, said the investigation is essential to future space missions. "If we are really going to do long-term exploration in space, we have to know what happens when we remove ourselves from real-time cues," Monk said. The sleep study may also help people on Earth who undergo shift changes at work or who suffer from jet lag. Results of the study may also help researchers better understand sleep patterns.

Earlier today crew members resumed musculoskeletal experiments on the Torque Velocity Dynamometer -- a device similar to exercise equipment found in a gym. The study is intended to determine how spaceflight affects muscle size and strength. With sensors monitoring muscle activity, they performed exercises with their right legs as measurements were made of their muscle strength, power and endurance. Mission Commander Tom Henricks, Pilot Kevin Kregel, Thirsk and Favier today resumed tests on the Performance Assessment Work Station, which is used to determine the effects of microgravity on thinking skills and mental reaction over the duration of the mission. By comparing information from the flight and from the later tests performed on the ground, the investigators may be able to quantify the effects of spaceflight on each of the mental skills measured. In the future, this information may be used to optimize work schedules in space. The goal is to maximize each crew member's productivity and job satisfaction during extended missions.

In the area of microgravity research, Payload Commander Susan Helms and Thirsk placed an experiment into the Advanced Gradient Heating Facility that measures the speed at which a mix of pure aluminum and an aluminum-nickel alloy must solidify to engulf rather than push away zirconia particles. The study examines aspects of processing alloys in a microgravity environment that may improve the processing of alloys on Earth.

After the experiment was placed into the high-tech furnace this afternoon, investigators at Marshall discovered that the heating facility was not providing data readouts. Ground controllers instructed Payload Commander Susan Helms to power down the heating facility, and after about 30 minutes, it was turned back on and the flow of data resumed.

This morning, the first half of the Bubble and Drops Interaction experiment led by Dr. Rodolfo Monti of the University of Naples, Italy, was run in the Bubble, Drop and Particle Unit. This investigation studies the interaction between moving, pre-formed bubbles and the melting and solidifying edge of a solid.

The second part of this experiment, which was scheduled for today, is designed to examine the way droplets are captured by or pushed away from a moving solidification front. The experiment calls for the injection of water drops of different diameters into an alloy that is in a liquid state to study drop behavior as heat is applied. However, difficulties encountered with the injector prompted the crew to instead place a boiling experiment originally scheduled for Wednesday into the Bubble, Drop and Particle Unit.

The experiment, designed by Dr. Johannes Straub of the Technical University in Munich, Germany, looks at heat transfer during boiling. Because boiling is an efficient way to exchange heat, it is used in many energy conversion systems on Earth. Systems which may benefit from research in this field include cooling systems for high-powered electronic devices, such as computer chips. The same experiment had a similar run on Sunday.

On Tuesday, July 2, 1996, 6:00 p.m. CDT, STS-78 MCC Status Report # 26 reports:

The thirteenth flight day of Columbia's STS-78 mission came to a close earlier this afternoon following another busy day of science investigations in the Spacelab module housed in the orbiter's payload bay.

The seven astronauts worked with a variety of experiments investigating the effects of microgravity on the human body. Studies of muscle strength and energy expenditure as well as astronaut pulmonary function continued throughout the day, while processing of advanced semiconductor materials and alloys in the Advanced Gradient Heating Facility proceeded uninterrupted.

Mission Commander Tom Henricks talked about Columbia's flight with the NBC News Channel early this morning discussing the experiments being conducted on board. Henricks explained that the crew is shifting its scheduled sleep period 25 minutes earlier each day, in part to support an early morning wakeup call on landing day, but also as an investigation into circadian rhythms and their effect on crew performance.

With that shifting sleep schedule, the astronauts are now scheduled to be awakened by Mission Control shortly after midnight central time -- at 12:14 a.m.

Columbia continues to operate trouble-free as it circles the Earth once every 90 minutes at an altitude of 168 statute miles.

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