
Lunar bases may need to be quake-proof (2006) - curtis
https://science.nasa.gov/science-news/science-at-nasa/2006/15mar_moonquakes
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lisper
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.

~~~
landryraccoon
> 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

I have to ask, what do you mean by sustainability here? Biological life has
existed on earth for about 2 billion years, the human race for a million years
and civilization for thousands of years. So in what sense is life on earth not
sustainable, and what would have to change for you to consider it sustainable?

In the ultimate long run life anywhere isn't sustainable; the sun will
eventually die and then the universe itself will experience heat death. So
what's your cut off?

~~~
nawgszy
>what do you mean by sustainability

Biological life existed for 5 orders of magnitude longer than civilization
without the sort of devastating consequence civilization has wrought.

The cut off is civilization suggesting that it is no more disruptive than
biological life to the long term sustainability of itself, but that is just
obviously not looking like the case right now. Exponential population growth
in a resource-constrained system will hit a limit and the result will not be
pretty.

~~~
njarboe
"Exponential population growth in a resource-constrained system" is how
biological systems have behaved for billions of years. It may not be pretty
but very natural.

~~~
TeMPOraL
True. But also: natural sucks, and we want a better outcome.

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TeMPOraL
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
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._

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WalterBright
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.

~~~
pacificmint
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
Ironically, a lot more on-the-ground investigation has been done on Mars than
the moon. I suspect there's a lot more useful stuff waiting to be found. All
we've looked at from the moon are a few pounds of rocks from a handful of
sites.

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

~~~
wolfgang42
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
What kind of isotopes was nasa putting in their ALSEPs that the output dropped
off over mere years?

~~~
wolfgang42
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_ge...](https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator#Fuels)

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obilgic
Please add 2006

~~~
sctb
Thanks! Updated.

