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posted by
martyb
on Wednesday June 08 2016, @09:17AM
from the build-a-space-elevator-on-the-moon dept.
from the build-a-space-elevator-on-the-moon dept.
NASA seems hell bent to go to Mars, but can't afford to on its own.
Its international partners have no stomach for that — they would would rather return to our moon and build a base there for further exploration.
Doesn't going back to the moon make more sense? Build a base on the moon, and use its low gravity and possible water at the poles as propellant for further space exploration?
Why not the moon first?
http://www.theverge.com/2016/6/7/11868840/moon-return-journey-to-mars-nasa-congress-space-policy
Links:
From NASA itself, in 2008: https://www.nasa.gov/centers/goddard/news/series/moon/why_go_back.html
The all-knowing, ever-trustworthy: https://en.wikipedia.org/wiki/Colonization_of_the_Moon
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Should We Skip Mars for Now and Go to the Moon Again?
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heavy, adj.:
Seduced by the chocolate side of the force.
(Score: 2) by Immerman on Wednesday June 08 2016, @08:01PM
0) Particle radiation comes in two flavors: charged (can be deflected by magnetic fields, so the ISS is mostly safe within the Earth's magnetosphere) and uncharged (blocked by direct nucleus impacts, shielding scales roughly linearly with the amount of mass, with only a slight variations due to density). Charged could hypothetically be reduced with magnetic shielding, uncharged probably not. Meaning you need ~14lb/in^2 of shielding to approach the shielding levels at the Earth's surface. That's going to be ridiculously expensive in space for the foreseeable future so, if you want shielding, you need to go to another moon/planet/asteroid. At which point you have plenty of radiation shielding available and don't really need magnetic shielding anymore.
Basically, the only place we're likely to see improvement in shielding is for traveling between large masses, and we can already do that with cancer risks lower than associated with many occupations and environments on Earth.
1) You do understand that all such "artificial gravity" experiments can only be done in space, right? And would consume a sizable percentage of the current research infrastructure. Unless someone quietly developed gravity shields, we can only really fake *increases* in gravity (typically using centripetal force, which also introduces additional variables in the form of torques and tidal effects). Also, like any medical research, such experiments would only be directly relevant to the species studied. If you want to know how low gravity will effect humans, you have to send humans. And fortunately there doesn't appear to be any shortage of volunteers, so the only genuine problem is how to manage the PR for the inevitable unpleasantness that will afflict the first wave. And you'd have to do that regardless, because there's inevitably going to be things you didn't think to test, and accidents will happen as well.
Meanwhile, the problems known to exist with microgravity do not seem to be, in and of themselves, fatal, and can mostly be mitigated with an appropriate exercise regime. Low gravity would presumably further mitigate the problems. So unless you can suggest a reason why low gravity might be worse than none, the presumption is that humans should be able to survive a prolonged period in low-gravity situations. Their life expectancy may be lower, their eyesight may degrade faster, and they might not be able to survive returning to Earth, but so long as the volunteers are willing to accept that price, it's largely a non-issue. Plenty of people work jobs right here on Earth with far greater risks.
The most problematic issue will likely be reproduction - but we've managed to breed many plants along with frogs, salamanders, and fish in microgravity, sea urchins apparently didn't do so well. Mammalian reproduction looks somewhat more problematic, with mouse embryonic cell division occurring much more slowly, on average, in simulated microgravity, but that might also be due to the deeply unnatural motion associated with the simulation, we'll have to test that in space to know more. Of those embryos eventually implanted in females, they developed to healthy births though at lower numbers than in normal litters.
So yeah, definitely still more research to be done on that front. Presuming humans behave similarly we might only have to deal with effectively reduced fertility due to higher early-term spontaneous abortion (already possibly as high as 25-75%, though I can't find any solid numbers), or problems could continue after implantation in sustained micro-g leading to high rates of birth defects without aggressive preventative measures. And whether such problems will also manifest in low-G environments, and to what extent, remains to be seen. However, gamete health seems unaffected by microgravity, so even in the absolute worst case, space habitats would simply require simulated gravity "maternity wards" if they wanted natural population growth. The more pressing question would be how much damage the simulated gravity would do to mothers acclimated to low-G.
Basically, to do the experiments you want to do, that haven't already been done, in a radiation-shielded environment, we need to have laboratories on the Moon or Mars. Or an asteroid, but that adds a bunch of additional challenges. So then the question becomes, what are the relative costs and benefits of manning those labs with people rather than remotely operated semi-autonomous robots. Robots would undoubtedly be cheaper per 'bot in terms of dollars and lives, but probably far more expensive in terms of the timescale at which research is accomplished. As the sentiment is sometimes expressed, almost everything Opportunity accomplished in it's decade-plus on Mars, could have been accomplished in a few days by a grad-student with a similar lab.
(Score: 2, Interesting) by khallow on Thursday June 09 2016, @03:00AM
1) You do understand that all such "artificial gravity" experiments can only be done in space, right? And would consume a sizable percentage of the current research infrastructure. Unless someone quietly developed gravity shields, we can only really fake *increases* in gravity (typically using centripetal force, which also introduces additional variables in the form of torques and tidal effects). Also, like any medical research, such experiments would only be directly relevant to the species studied. If you want to know how low gravity will effect humans, you have to send humans. And fortunately there doesn't appear to be any shortage of volunteers, so the only genuine problem is how to manage the PR for the inevitable unpleasantness that will afflict the first wave. And you'd have to do that regardless, because there's inevitably going to be things you didn't think to test, and accidents will happen as well.
Artificial gravity is not that hard to test. You could do that with a few hundred million dollars in satellite. And medical testing has shown that testing other species like mice are relevant to humans.
(Score: 2) by Immerman on Thursday June 09 2016, @03:09PM
Actually something like 90% of medical discoveries in mice don't end up translating to humans. We don;'t use them because they're accurate, but because they're cheap, live fast, (so that many long-term effects manifest quickly) and research strains are inbred to the point that they're only a stones-through from all being clones, drastically reducing genetic variables when testing. They give us rough guidance into further research, not much more than that.
For your satellite, fair point. I could see a little automated mouse cage with cameras, etc. coming in at that price range, and then gently de-orbit for dissection after a couple years. Couldn't be very big though, after all you need a lot of shielding if you want atmosphere-grade radiation shielding - covering a 1-foot diameter sphere with 14lb/in^2 of shielding comes to 6300lb, (assuming zero-thickness shielding. Geometric realities will push that number considerably higher, though high-density shielding will push it down again, might roughly cancel out). A pair of those, tethered together, and you could spin them up to whatever "gravity" you wanted. You might want to ask a biologist how much human intervention is required to keep caged mice healthy though - full automation for a multi-year experiment could prove challenging. It'd be a real shame if they got stressed and ate each other before you could dissect them.
(Score: 1) by khallow on Thursday June 09 2016, @04:03PM
Actually something like 90% of medical discoveries in mice don't end up translating to humans.
I imagine a fair number of those discoveries are due to spurious p-testing and don't end up translating to mice either. And 10% is a pretty good rate.
(Score: 2) by Immerman on Thursday June 09 2016, @05:37PM
Heh, don't get me started.
Still, if the results were due to spurious p-testing then I'd expect to see similar spurious positives in human trials by the same statistically incompetent researchers.
(Score: 1) by khallow on Thursday June 09 2016, @10:31PM
Still, if the results were due to spurious p-testing then I'd expect to see similar spurious positives in human trials by the same statistically incompetent researchers.
And your point is? The end result is still that the mouse model has relevance to the human model which really is all anyone is saying here. That is still a lot better than the low gravity research to date.
(Score: 0) by Anonymous Coward on Saturday June 11 2016, @09:04AM
Still, if the results were due to spurious p-testing then I'd expect to see similar spurious positives in human trials by the same statistically incompetent researchers.
I thought that was what we had.