Electrodes on the sleep net and sensors in the sleep suit monitor brain waves, eye movements, muscle tension, body movements and respiration. The electrodes and sensors are connected to a digital sleep recorder that records a variety of measurements as they sleep. Mukai also will swallow a capsule containing either melatonin or a placebo as part of the sleep study. Glenn removed the Holter monitor electrodes and data recorder he has worn for the past 24 hours, recording his heart rhythm on orbit, as part of an investigation of heart rate variability during space flight. Blood samples were again taken from Glenn and ESA astronaut Pedro Duque as part of the experiment monitoring the changes in muscle tissue in space.
Colloids are systems of fine particles suspended in fluid.
Researchers hope to learn more about how the organization of atoms changes as they form into orderly solid structures. Duque deactivated these two experiments for the remainder of the mission. All systems on board Discovery continue to operate well. The next STS-95 status report will be issued at approximately 6 a.m. Central time Thursday.