Q: After your return to Earth did you have trouble sleeping? (Tom Pogue, Waldron, Arkansas)
On my first night back on Earth after 18 days in orbit (my STS-80 Columbia mission), I slept fitfully. It was strange lying on a mattress again, and drifting off to sleep, I was sure that if I lost the grip on my pillow, I’d float up to the ceiling and stay there! That was one strange and restless night—I’d never squeezed a pillow so hard! But even this unsettled sleep was welcome, because by bedtime it had been close to 24 hours since I had woken up in orbit that morning on Columbia.
Being tired did help me get to sleep on my first night back, but I still had to deal with a kind of jet lag those first few days back, as I adjusted from shuttle time to normal day and night back on Earth in Houston.
Returning NASA space station crews face a westward time shift of about 5 or 6 hours, depending on the season, as they transition from Coordinated Universal Time in space to the local time at their home back in Houston. After landing, their bedtime is 5-6 hours later than it had been in orbit. Adjusting to a time shift that large takes the better part of a week, helped along by the fatigue caused by once more experiencing Earth gravity 24 hours a day.