The STS-95 mission launched in October of 1998. Its seven-member crew performed a number of duties, including a variety of science experiments carried in the pressurized Spacehab module, the deployment and retrieval of the Spartan free-flyer payload, and operations with the HST Orbiting Systems Test (HOST) and the International Extreme Ultraviolet Hitchhiker (IEH) payloads carried in the payload bay.
The UCSD team, in collaboration with a group from Brigham and Women's Hospital at the Harvard Medical School, did a study of sleep on orbit, in a sleep experiment similar to that flown on Neurolab. Two subjects were instrumented for sleep with EEG, EOG, and EMG electrodes in a "sleep net," and wore the RIP Suit and harness, which provided respiratory movement, ECG, sound, light, pulse oximetry, and nasal air flow. All signals were recorded on the Digital Sleep Recorder. Body core temperature was measured constantly throughout the flight, and the subjects' cognitive performance was tested on days following instrumented sleep to see how the quality of sleep that the astronauts got affected their performance the next day. The subjects participated in experiment sessions before, during, and after the mission, and acted as their own controls.
An additional scientific study being performed as part of the sleep study on STS-95 is the study of aging, with John Glenn being one of the participants in the sleep experiment. Certain physiological changes that occur in space also occur with aging: cardiovascular deconditioning, balance disorders, weakening bones and muscles, a depressed immune response, as well as disturbed sleep. An important difference, however, is that these changes are reversible in astronauts. The change in sleep pattern that typically comes with aging is early waking and fragmented or otherwise disturbed sleep. Optimal alertness during the day and sound sleep at night, valuable qualities on Earth and in space, require proper synchronizing of the human circadian pacemaker. Thus, we seek to better understand how aging and space flight affect the mechanisms governing circadian rhythms.
For more information about the STS-95 mission, please see these pages:
You may also visit our Photo Gallery to see pictures of our activities during STS-95 training and baseline data collection.