Not that sleep-deprivation is the biggest danger to astronauts in space, this article includes some interesting sleep related facts:
- Nearly half of the medications the astronauts take with them are sleep aids
- Light sensitive cells in the eye use light to regulate the hormone melatonin, which in turn regulates our sleep-wake cycles, which is something that could also be used to help astronauts keep a sleep cycle
Mistakes made due to sleep deprivation could have even greater consequences in space so this is a big issue for NASA. Makes me wonder if the loss of that $100,000 tool bag recently was in part caused by astronaut fatigue. You can track its progress here.