Thursday, August 25, 2016

Transportation that Builds Momentum

There is no way around it. The different resources of the Moon are in different places, and they don't seem to be close together. Mapping of resources is really patchy, low-resolution, and incomplete, so maybe there is a sweet spot that helps with this we have only to discover. Probably not, though, and even if there is, if you are talking about serious development, you are going to need to go get things from far away sooner or later.

Building first at the equator simplifies some things but runs into this as soon as the water supply comes up. For all that it is much easier to build big quickly at Lalande Crater, it has advantages in trajectories to and from Earth, and has much more iron, potassium, phosphorus, thorium, and rare earth elements than the poles, all of its water has to be delivered. A base at the poles could get its water from permanently shadowed craters once the machinery to do so had been developed and built. That could prove difficult and expensive though - we don't know yet.  If you set up an efficient supply route from Earth, supplying enough water doesn't get problematic until it is time to expand the colony from the initial crew of 30 to a population of hundreds. Even then, if you skipped putting in giant swimming pools it is conceivable you could simply add a few cargo runs  to your schedule loaded with nothing but water from Earth and stay within your budget. However, a place on the Moon where people are supposed to live for the rest of their lives really ought to have giant swimming pools. So, the trick is how to bring kilotons of water to the colony for those residents. And just aside from that you will want to be able to move kilotons onto and off of the Moon anyhow, so this is really just the first, most obvious case of that need.

Wednesday, August 17, 2016

Health Tips on the Moon - Part 3

It is time to speak of radiation on the Moon. First i am going to explain it a bit, and point out things a lot of people don't know. One, we can only make decent guesses how much radiation there is on the Moon. Two, we don't know what it will do to people. Three, a bit of shielding makes it much worse, not better.

One - We have no direct measurements of radiation levels on the Moon's surface, and modeling that environment with software is extraordinarily complex. This paper based on modelling found galactic cosmic radiation (GCR) fluctuates between 0.38 Sv/yr at solar minimum and 0.11 Sv/yr during solar maximum. (The solar wind scatters GCR particles that enter the solar system, and when it is stronger less penetrate to the inner solar system.) The Curiosity rover measured 0.66 Sv/yr in deep space on its way to Mars, 0.23 Sv/yr on the Martian surface in 2013, when solar activity was about half way between its minimum and maximum. The Moon is different than Mars because it has no atmosphere, but taking all those figures, using an average of 0.25 Sv/yr overall is probably within, say, 50% of the truth.

Two - Again using a lot of modeling and statistics, the estimate is that 0.5 Sv/yr increases an astronaut's chances of cancer by about 3% to 5%. In order to not increase those chances beyond that amount, radiation dose for a whole career is not to exceed 1 to 4 Sv, depending largely on the age and gender of the astronaut. There isn't enough data to consider other possible health risks due to radiation exposure, and even the figures used are a guesstimate. Actual effects could be much less or much more, they could vary a lot from person to person, and other factors like diet and exercise could change these probabilities greatly.

Tuesday, August 9, 2016

Health tips on the Moon - Part 2

Before i do anything else i am going to deliberately refer you away from this blog, to the wonderful Lunar Swimming entry on Randall Munroe's What If blog, and please note that i asked that question. Please return for further discussion of the proposition.

All done? Okay, hopefully you noticed the bit that points out 'The inertia of the water is the main source of drag when swimming, and inertia is a property of matter independent of gravity. The top speed of a submerged swimmer would be about the same on the Moon as here—about 2 meters/second'. So, if you can swim, you can load your muscles just as much as they are loaded when you swim on Earth, and swimming is one of the best forms of exercise there is. It develops all your main muscle groups while not straining your joints. The pressure of the water against you could also be useful for encouraging redistribution of fluids, if the low gravity isn't enough to keep the fluids in our body where they ought to be (which it might be, and if it isn't, the water pressure while swimming might not help - speculation here).

Let us come back in a bit to the much more intriguing fact you could leap out of the water like a dolphin, and the splashiness matter, and talk about how else so much water can be useful. And let us also come back to the point that water is heavy and it would take a lot of infrastructure to get the water for large swimming pools to the colony, and more infrastructure still to do the audacious things with them i am about to propose. That is all just a matter of how far along the development path of a colony something like this would make sense. Development timelines change a lot when people decide they want something to happen, thus the relevant thing is to talk about the neatest possibilities.

Monday, August 1, 2016

Health tips on the Moon - Part 1

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:

You go in the box then it spins real fast