I’ve been mulling how to address effective exercise on the Moon to address a host of health problems that come with low gravity. The main issues are loss of muscle and bone mass, and problems associated with redistribution of fluids, in particular how this can degrade eyesight. Also with the first habitat model coming along, i took a more critical look at its radiation protection and beefed it up.
As with many things, the exercise problem gets a lot easier if you have plenty of space to work with. That is why the first virtual moon colony being made is something pretty developed, to really assess the potential. Two things are being put in for exercise that hopefully could make a big difference. One is a human-powered centrifuge, a variation on the kind used to test human tolerance to high g forces. One the German space agency has is shown below:
In the low gravity of the Moon, two or three people could slowly spin up something much larger until the effect was like a full gravity pressing people against the outer wall of a connected wheel, like old-fashioned Rotor amusement park rides. As evidence it really doesn’t take that much power to revolve such a structure fast enough, I recall two older boys once had some fun spinning a roundabout, which is similar, so fast that i was no longer strong enough to hold on and went flying off, and i was not the only squealing kid on the ride begging them to stop. Ah, childhood… This is how long-term memories are formed…
So, it seems reasonable that in lunar conditions something that works on the same principle could be spun to the equivalent of one g and kept there by a few people. It would be good aerobic exercise for those keeping it going, time in one g for those who are on it, and it doesn’t need any motors or a power supply so it isn’t nearly as hard to build. In fact most of the structure could be made on-site. Everybody wins.
(The spoke support system probably isn’t adequate, but this is just a sketch right now.) Notice the 2-level central stand where up to 12 people could cooperate in keeping the wheel spun up, by first leaning against one of those red handles and pushing on it while trotting around the green platform, and then standing around the platform perimeter and hauling on the handles as they pass by. To be useful therapy for the people on the wheel, the speed for the equivalent of 1 gravity probably needs to be maintained for at least, say, a half hour, daily or a few times a week. Typically the human body keeps itself ready for the heaviest loading that is regularly experienced, so it is reasonable to suppose that such a level of exercise would keep lunar residents in decent shape. Crew on the ISS have to exercise much more than that, but they aren’t able to do so in artificial gravity. The hope is that would make the key difference. As it is a group activity where everyone benefits, and would likely be sort of fun, it doesn’t seem like it would be a problem to arrange for everyone to take turns, sometimes pushing the wheel, and sometimes riding on it. Turning the wheel would provide good aerobic exercise, working out on the wheel would be the anaerobic, strengthening component of their exercise program.
To be really effective, those on the wheel would need to do exercises while under that force, stuff that loads there bones and muscles well. Squats, push-ups, sit-ups, chin-ups, lunges, stuff like that. Just being on the wheel though would also be helpful. The crew on the International Space Station have some difficulties because there is no gravity keeping fluids properly distributed in their bodies, and so it collects in their upper bodies and especially in their heads. Pressure on their eyeballs due to that is the leading explanation for the vision problems they often have. Their sinuses also often get clogged. Being on the wheel would provide relief from that. The wheel has a wide enough radius to limit the dizziness people feel on such structures when they move their heads around - in this model it is 12 m. Spending an hour or more on it shouldn’t cause nausea, though it might take people a bit to adapt to the sensations.
It isn’t until we contemplate a space large enough for such an innovation, with the infrastructure in place to create it right there on the Moon so the expense isn’t exorbitant, that we can really get our juices flowing and imagine a future colony in detail. This is hopefully a good example of that process. In the next few days i’ll post about another very useful exercise option - swimming pools. That implies a lot of infrastructure too, more than this does even. But that is the goal, right? The thing is to outline the path leading there better and better.