Simulation Using LRO Data Shows More Locations With Ice on the Moon 55
ananyo writes "Water ice on the Moon may be more widespread than previously thought. Permanent shadows have been spotted far from the lunar poles, expanding the number of sites that would be good candidates for exploration by robotic rovers — or even for the locations of lunar bases."
Re:This is exciting (Score:4, Interesting)
Re:This is exciting (Score:5, Interesting)
What I'd be interested on knowing:
How fast would we have to spin something to approximate 1G, and how big would it have to be? (Several times the height of a human is my guess, in order to prevent having stratified gravity.)
Is 1G even optimum or necessary to retain bone mass and a strong heart?
Smaller diameters of "space station" require a higher angular velocity, but in principle there is no specific size restriction if you simply want to achieve a 1g accelleration at floor level. However, using a small diameter has a couple of problems:
1. The accelleration gradient is more extreme (equivalent to gravitational tidal forces). e.g. for a capsule twice the height of a human, your feet would be at 1g, but your head (being in the centre) would be in 0g. Use a bigger diameter and a slower angular velocity and you will reduce the gradient.
2. The coriolis effects associated with high angular velocities make it extremely unpleasant to move around in a fast spinning (hence small diameter) capsule. According to Wikipedia [wikipedia.org] you need to spin at under 7 RPM, preferably around 2 RPM, to make this manageable. At 2 RPM you need a diameter of about half a kilometer to achieve 1g. 7 RPM is a bit more managable, requiring a diameter of 40 metres. Rather than building a cylindrical capsule, a better option might be to have a pair of capsules tethered together with a 500 metre tether.