1.   For a sleep experiment, Glenn will swallow melatonin or placebo pills before retiring on four nights.

2.   Glenn was dropped from one top priority sleep experiment that involved taking a small amount of the hormone melatonin.

3.   Japanese physician-astronaut Chiaki Mukai will participate in all phases of the sleep experiment.

4.   Researchers are conducting sleep experiments on the mission.

5.   Similarly, in the sleep experiment, Glenn may not turn out to be typical.

6.   The sleep experiment will require Glenn to don a sleep cap with electrodes to monitor his heart rate, respiration and movement.

7.   The use of melatonin constitutes about one-third of the sleep experiment.

8.   The use of melatonin constituted about one-third of the Discovery sleep experiment.