Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!nrl-cmf!ames!vsi1!apple!ems From: ems@Apple.COM (Mike Smith) Newsgroups: sci.space Subject: Re: `Days' in space Message-ID: <551@internal.Apple.COM> Date: 7 Feb 89 01:50:29 GMT References: <208@loci.UUCP> <327@antares.UUCP> <10285@well.UUCP> <768@mv03.ecf.toronto.edu> <10365@well.UUCP> Organization: Circle C Shellfish Ranch, Shores-of-the-Pacific Ca Lines: 35 In article <10365@well.UUCP> tneff@well.UUCP (Tom Neff) writes: >I strongly urge all you cave dwellers out there to factor in the >resource cost, not just of spending X months *at equilibrium* at some >artificial day length, but of sustaining two or three *transitions* >between day lengths, all the while trying to run a Mars mission at its >most critical moments. This pre-supposes that there IS a resource cost in making a transition or that there is a resource savings at some schedule. I would make the (bald faced, poorly supported) assertion that this is not true. I underwent many transistions (during a study described in a prior posting) and spent weeks at a time on free run, then shifted to another schedule and free run. My resource consumption profile? Consistently downward over time, leveling out at about a starvation level of calories. (1100-1200/day). The dominant factor BY FAR was that there wasn't much to do in a room 11x17 with two other guys, bunk beds, chairs, and a TV, other than be a couch potatoe. Since most of my time was spent laying down or sitting, I didn't consume much. Period. Free run day or day-night schedule. The cost of a transisition is NOT resources, but rather PERFORMANCE. We were awakened at the bottom of our {heart rate, temperature, etc} curves and put on a flight simulator. Being at a bottom (or going through a desyncronization) resulted in SIGNIFICANT drops of performance. The conclusion? Keep folks syncronized, but out of phase. (i.e. have one person who is awake and near a body temperature high point on each shift so that they will perform well in an emergency.) The exact interval for syncronization doesn't matter much, but time in the range of 22-28 hours are easiest for most folks to accept (given our sample of 9 people in a 3 1/2 month study). Unless there is an overwhelming need for something other than 24, it wouldn't be worth the confusion of using a non-standard day, IMHO.