9 ms·

Lunar bases may need to be quake-proof (2006)

69 points by curtis 9y ago

TeMPOraL 9y ago
Interesting. Never heard of that before. I didn't think there could be regular quaking in non-seismically-active bodies. > March 15, 2006: NASA astronauts are going back to the moon This broke my heart.
- morganvachon 9y ago
  According to the article, the moon is seismically active. > That's the surprising conclusion of Clive R. Neal, associate professor of civil engineering and geological sciences at the University of Notre Dame after he and a team of 15 other planetary scientists reexamined Apollo data from the 1970s. "The moon is seismically active," he told a gathering of scientists at NASA's Lunar Exploration Analysis Group (LEAG) meeting in League City, Texas, last October.
obilgic 9y ago
Please add 2006
- sctb 9y ago
  Thanks! Updated.
- deleted 9y ago
  [deleted]
lisper 9y ago
This will probably be a very unpopular point of view here on HN, but I think it needs to be said: if we can't figure out how to build a long-term sustainable society here on earth, there is no way we're going to be able to build a long-term sustainable society on the moon, or anywhere else. And the only way to build a long-term sustainable society is to figure out how to build an economy that does not rely on exponential growth. We haven't done that yet, and until we do, no technology will save us. Even if we could colonize new planets at will and expand at the speed of light, that only gives us polynomial (t^2) resources. Polynomial resources can never sustain exponential growth. Worrying about moonquakes is the ultimate bikeshedding.
- zitterbewegung 9y ago
  Hawking argues that due to the fact that we can't have a long term sustainable earth we need a backup in the form of a moon base and or mars outpost .
- mschuster91 9y ago
  > And the only way to build a long-term sustainable society is to figure out how to build an economy that does not rely on exponential growth. Oh, there was - look back in ancient history, with tribes using only what they needed in terms of resources and land (and for what its worth, some of these cultures still exist in remote places). The problem is capitalism and the imperialism that rose with it, beginning in Ancient Rome. By now, it's deeply ingrained into our societies, even those who call themselves "communist". I believe that only the natural constraints of a moon/Mars base, together with their initially small population, will force the settlers to cooperate on equal basis and thus lead to a small-scale sustainable economy. The only problem is, small colonies won't be sustainable in genetic terms: there will be an "incest bottleneck", and the only way to solve this is to expand the population base - where the effects of a capitalist society will become apparent again more sooner than later...
  - visarga 9y ago
    Why do you think you need to do that? You can import sperm and eggs.
    - mschuster91 9y ago
      Because it's unsafe to depend on Earth providing said sperm and eggs - that a highly technologically advanced civilization as the Roman Empire could basically disappear with all their knowledge (e.g. running water, sewage channels, street building and other) in less than a hundred years should be a warning that this can also happen to Earth now. All it takes is an all-out nuclear war, an asteroid strike or a catastrophic volcano eruption. And I'm not sure if it's wise to send sperm/eggs via space craft... while "inside a human" the cells are protected from radiation and especially they're (re)generated, not so much when they're frozen in space.
steffenfrost 9y ago
Why would they turn off those seismometers? What a shame.
- wolfgang42 9y ago
  The seismometers were part of the Apollo Lunar Surface Experiments Packages (ALSEPs), which were powered by radioisotope thermal generators. RTGs use the heat from decaying radioactive elements to produce power, and gradually produce less energy over time as the isotopes decay into more stable elements. By 1977 the ALSEP RTGs were only producing enough power to run either one experimental package or the radio transmitter at once; they probably would have stopped working altogether in a few more years anyway and it's better to have a controlled shutdown rather than a failing radio transmitter cluttering up the airwaves. Wikipedia also mentions "budgetary considerations", and apparently they wanted the ALSEP control room for another project as well. Edit: I've just found [1], which adds a few additional details: first, they were designed for a lifetime of one year, so 1977 was well beyond their expected activity; and second, after they were decommissioned they continued to send carrier signals (but no data) which were used for various purposes. [1]: https://www.hq.nasa.gov/alsj/HamishALSEP.html https://www.hq.nasa.gov/alsj/HamishALSEP.html More detail than you ever wanted to know can be found in the ALSEP termination report: https://nssdc.gsfc.nasa.gov/misc/documents/b32116.pdf https://nssdc.gsfc.nasa.gov/misc/documents/b32116.pdf
  - ouid 9y ago
    What kind of isotopes was nasa putting in their ALSEPs that the output dropped off over mere years?
    - wolfgang42 9y ago
      They were using Plutonium 238, which is the most common RTG fuel. The Wikipedia page on RTGs has a fairly comprehensive overview of the possible candidate fuels[1]; one advantage of 238Pu is that it requires the least amount of shielding, an important consideration when launching things into space. Pages 101-105 of the termination report I linked to above have the power output curves for the various RTGs, showing the decay curve (1 lunation ~= 1 month). [1]: https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator#Fuels https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...
WalterBright 9y ago
Building a moon colony seems far more practical and useful than a Martian one. On both you'd need pressure domes, shielding, etc., so why not be a couple days away rather than a year? You can have a much quicker cycle of trying and adapting than on Mars, a couple orders of magnitude faster. Because of the moon's low gravity, it is a fine place for manufacturing big, heavy equipment for space travel. And lastly, the technology developed for a sustainable moon base ought to transfer well to Mars.
- wfunction 9y ago
  > so why not be a couple days away rather than a year Hm, maybe because you'd get twice the gravity and a "day" that lasts closer to 24 hours than 24 days?
  - WalterBright 9y ago
    Does the diurnal cycle matter if you must stay within a shielded dome? Lower gravity doesn't matter as much if you can be regularly cycled back to earth.
- pacificmint 9y ago
  I used to be of the same opinion as you, but there are actually some good counter arguments: 1) Two week day/night cycle: This means it would be hard to power your base with solar energy. You'd need massive battery banks. Or another power source. You could try nuclear, but cooling might be a challenge without air or water. Mars has a slightly longer day than earth, which makes solar power much more viable (though solar insolation is less than on earth) 2) No atmosphere, so all Oxygen has to be brought in (unless we find it somewhere else on the Moon). Also any carbon needed to grow plants needs to be brought in. Mars has a thin atmosphere, but we could get Oxygen and Carbon from it. 3) It's not clear if we can find water on the moon. Mars almost certainly has water underground, and for sure at the pole. 4) The lower gravity might have long term effects on humans. Though to be fair, we don't know if Mars gravity will be harmful as well.
  - WalterBright 9y ago

69 points by curtis 9y ago

Interesting. Never heard of that before. I didn't think there could be regular quaking in non-seismically-active bodies. > March 15, 2006: NASA astronauts are going back to the moon This broke my heart.

morganvachon 9y ago
According to the article, the moon is seismically active. > That's the surprising conclusion of Clive R. Neal, associate professor of civil engineering and geological sciences at the University of Notre Dame after he and a team of 15 other planetary scientists reexamined Apollo data from the 1970s. "The moon is seismically active," he told a gathering of scientists at NASA's Lunar Exploration Analysis Group (LEAG) meeting in League City, Texas, last October.

obilgic 9y ago

Please add 2006

sctb 9y ago
Thanks! Updated.
deleted 9y ago
[deleted]

lisper 9y ago

This will probably be a very unpopular point of view here on HN, but I think it needs to be said: if we can't figure out how to build a long-term sustainable society here on earth, there is no way we're going to be able to build a long-term sustainable society on the moon, or anywhere else. And the only way to build a long-term sustainable society is to figure out how to build an economy that does not rely on exponential growth. We haven't done that yet, and until we do, no technology will save us. Even if we could colonize new planets at will and expand at the speed of light, that only gives us polynomial (t^2) resources. Polynomial resources can never sustain exponential growth. Worrying about moonquakes is the ultimate bikeshedding.

zitterbewegung 9y ago
Hawking argues that due to the fact that we can't have a long term sustainable earth we need a backup in the form of a moon base and or mars outpost .
mschuster91 9y ago
> And the only way to build a long-term sustainable society is to figure out how to build an economy that does not rely on exponential growth. Oh, there was - look back in ancient history, with tribes using only what they needed in terms of resources and land (and for what its worth, some of these cultures still exist in remote places). The problem is capitalism and the imperialism that rose with it, beginning in Ancient Rome. By now, it's deeply ingrained into our societies, even those who call themselves "communist". I believe that only the natural constraints of a moon/Mars base, together with their initially small population, will force the settlers to cooperate on equal basis and thus lead to a small-scale sustainable economy. The only problem is, small colonies won't be sustainable in genetic terms: there will be an "incest bottleneck", and the only way to solve this is to expand the population base - where the effects of a capitalist society will become apparent again more sooner than later...
- visarga 9y ago
  Why do you think you need to do that? You can import sperm and eggs.
  - mschuster91 9y ago
    Because it's unsafe to depend on Earth providing said sperm and eggs - that a highly technologically advanced civilization as the Roman Empire could basically disappear with all their knowledge (e.g. running water, sewage channels, street building and other) in less than a hundred years should be a warning that this can also happen to Earth now. All it takes is an all-out nuclear war, an asteroid strike or a catastrophic volcano eruption. And I'm not sure if it's wise to send sperm/eggs via space craft... while "inside a human" the cells are protected from radiation and especially they're (re)generated, not so much when they're frozen in space.

steffenfrost 9y ago

Why would they turn off those seismometers? What a shame.

wolfgang42 9y ago
The seismometers were part of the Apollo Lunar Surface Experiments Packages (ALSEPs), which were powered by radioisotope thermal generators. RTGs use the heat from decaying radioactive elements to produce power, and gradually produce less energy over time as the isotopes decay into more stable elements. By 1977 the ALSEP RTGs were only producing enough power to run either one experimental package or the radio transmitter at once; they probably would have stopped working altogether in a few more years anyway and it's better to have a controlled shutdown rather than a failing radio transmitter cluttering up the airwaves. Wikipedia also mentions "budgetary considerations", and apparently they wanted the ALSEP control room for another project as well. Edit: I've just found [1], which adds a few additional details: first, they were designed for a lifetime of one year, so 1977 was well beyond their expected activity; and second, after they were decommissioned they continued to send carrier signals (but no data) which were used for various purposes. [1]: https://www.hq.nasa.gov/alsj/HamishALSEP.html https://www.hq.nasa.gov/alsj/HamishALSEP.html More detail than you ever wanted to know can be found in the ALSEP termination report: https://nssdc.gsfc.nasa.gov/misc/documents/b32116.pdf https://nssdc.gsfc.nasa.gov/misc/documents/b32116.pdf
- ouid 9y ago
  What kind of isotopes was nasa putting in their ALSEPs that the output dropped off over mere years?
  - wolfgang42 9y ago
    They were using Plutonium 238, which is the most common RTG fuel. The Wikipedia page on RTGs has a fairly comprehensive overview of the possible candidate fuels[1]; one advantage of 238Pu is that it requires the least amount of shielding, an important consideration when launching things into space. Pages 101-105 of the termination report I linked to above have the power output curves for the various RTGs, showing the decay curve (1 lunation ~= 1 month). [1]: https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator#Fuels https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...

WalterBright 9y ago

Building a moon colony seems far more practical and useful than a Martian one. On both you'd need pressure domes, shielding, etc., so why not be a couple days away rather than a year? You can have a much quicker cycle of trying and adapting than on Mars, a couple orders of magnitude faster. Because of the moon's low gravity, it is a fine place for manufacturing big, heavy equipment for space travel. And lastly, the technology developed for a sustainable moon base ought to transfer well to Mars.

wfunction 9y ago
> so why not be a couple days away rather than a year Hm, maybe because you'd get twice the gravity and a "day" that lasts closer to 24 hours than 24 days?
- WalterBright 9y ago
  Does the diurnal cycle matter if you must stay within a shielded dome? Lower gravity doesn't matter as much if you can be regularly cycled back to earth.
pacificmint 9y ago
I used to be of the same opinion as you, but there are actually some good counter arguments: 1) Two week day/night cycle: This means it would be hard to power your base with solar energy. You'd need massive battery banks. Or another power source. You could try nuclear, but cooling might be a challenge without air or water. Mars has a slightly longer day than earth, which makes solar power much more viable (though solar insolation is less than on earth) 2) No atmosphere, so all Oxygen has to be brought in (unless we find it somewhere else on the Moon). Also any carbon needed to grow plants needs to be brought in. Mars has a thin atmosphere, but we could get Oxygen and Carbon from it. 3) It's not clear if we can find water on the moon. Mars almost certainly has water underground, and for sure at the pole. 4) The lower gravity might have long term effects on humans. Though to be fair, we don't know if Mars gravity will be harmful as well.
- WalterBright 9y ago