

Revisiting the Moon - dnetesn
http://www.nytimes.com/2014/09/09/science/revisiting-the-moon.html?ref=science&_r=0

======
AndrewKemendo
I always feel like a curmudgeon when the topic of manned space travel comes up
or really space exploration in general.

From my perspective I see literally thousands of ambitious projects yearly
that go unfunded that would do mankind magnitudes more good than sending
people into space or generally peering upward.

I have heard the arguments ad-nausea for why investment in space exploration
has a positive ROI and find none of them compelling. No, the handful of
"dreamers" that it produces is not worth the billions of dollars, No, the
handful of technologies [1] that we can find terrestrial use for as a
byproduct are not worth the billions of dollars spent.

If invisible braces were that big of a need we likely could have found the
solution through much cheaper means.

We should be putting our money into Fusion, AGI and longevity research. Not
walkabouts on the moon.

[1] [http://en.wikipedia.org/wiki/NASA_spin-
off_technologies](http://en.wikipedia.org/wiki/NASA_spin-off_technologies)

~~~
toxican
You say that as though we can't do both. Have you seen NASA's pathetic little
budget? And who's to say it has to be a government that does this? Companies
like SpaceX are stepping up and picking up NASA's slack at a rapid pace.

~~~
zachrose
Is it actually meaningful to compare NASA with SpaceX? My understanding is
that SpaceX's primary—if not only—client is NASA. If I've got this right,
doesn't it mean that the money still comes from the Feds and SpaceX is not
that different from Boeing/Douglas/North American in the Apollo era?

~~~
soperj
You're wrong. Most of their launches are not for Nasa.

------
digikata
I worry for humanity in the long term if the only broad direction we can give
ourselves are evaluated in the framework of ROI. The very calculation of ROI
assumes that there's a known and stable model for predicting both the
investment required and a known output. Comparing many ROIs estimates assumes
the slate of options covers the gamut of where one should invest - it could
work very well for a small or midsize company with limited options going
forward, but it feels like a huge fallacy to assume that covers an entire
nation - let alone all of mankind.

The best answer I can muster against framing the question in terms of ROI, is
that we suspect we could go to the moon and stay there longer than ever
before, and that puts us on a path of opening up vastly more unknowns, more
rapidly than we would otherwise encounter by staying on the Earth and sending
probes with limited sets of instruments, with narrow perceptions into space.

Indeed, why would anyone travel anywhere on Earth even, when it's cheaper to
look at pictures of the destination from the internet, or read the guidebook
and be done.

You could dismiss this as a purely humanistic argument, but if at least some
of our resources aren't allocated to get to places where we simply don't
strictly know the outcomes, we will simply will never grow beyond some
confines.

------
sp332
Do people really think of the moon as "as a problem solved and a bit retro"?
Anyone I've talked to about it would love to see people get back up there.
Especially with the recent, incredibly expensive Mars missions, it seems like
we could put a little more effort into checking out the Moon.

~~~
tokenadult
What would we find up there that we didn't find last time with a new moon
mission?

EDIT: I guess the assumption about basketball played on the moon is that most
of us would watch that on television. But how much would a team have to make
in TV advertising revenues to recover the cost of sending athletes to the moon
and keeping them alive there? (A similar question applies to the costs of
running the Olympics on the moon.) Ladies and gentlemen, those are fun jokes,
but is this kind of joking response going to prompt anyone to invest their own
money in a moon mission?

~~~
jacquesm
It's not what we would find up there it is what we could _do_ up there.

For one we could set up a lunar observatory.

~~~
dalke
What could a lunar observatory do that an orbiting one like the planned James
Webb Space Telescope or the proposed Advanced Technology Large-Aperture Space
Telescope couldn't?

~~~
jacquesm
Stay aloft indefinitely (or at least, for our purposes indefinitely).
Satellite based telescopes will always have a limited life-span, either they
end up dropping too low and de-orbiting or they run out of aiming propellant.

~~~
dalke
"Aloft" is a bit of a misnomer, I believe, for something sitting on the Moon.

Both of the space telescopes I mentioned are targeted for L2, which is well
beyond the Moon's orbit, so there's no chance they'll de-orbit. I believe they
use reaction wheels for pointing, not propellant, but as L2 is not stable,
you're right that it needs some fuel for station keeping.

On the other hand, the Moon has quakes, and large temperature swings. Wouldn't
that be much easier to set up an effectively stationary sunshield for the
stillness of L2 instead? Plus, the Moon blocks out about 1/2 the sky, which
seems like it might limit what you can do.

~~~
jacquesm
> "Aloft" is a bit of a misnomer, I believe, for something sitting on the
> Moon.

Sure :) But it's attaching something to a satellite rather than launching a
satellite. After all, the moon _is_ a satellite of the earth, but a natural
one rather than an artificial one.

~~~
dalke
I still don't see what science objectives it could do better than one of the
ones proposed for L2.

~~~
jacquesm
Really long term observations without atmospheric distortion, really long
baseline stuff with very precisely defined distances between the various
elements. I'm not an astronomer but there have been quite a few proposals for
such observatories, all have been shot down on practical grounds, not on
grounds of not having some kind of benefit.

There has been talk of very large liquid based mirrors (limited in size on
earth), the far side of the moon is free from radio interference from the
earth and a bunch of other proposals. All of them were shot down based on a
very simple observation: we don't have people on the moon, nor do we have a
power plant or a way to install this stuff or assemble it out of pieces after
landing it there.

But that might change.

~~~
dalke
There's no atmosphere distortion in L2 either.

"Really long term" on the Moon means dealing with moonquakes, which can last
for more than 10 minutes. That's going to affect any baseline distances.

We can get a much longer baseline in space than on the Moon. LISA and DECIGO
give some idea of how accurate we can expect to measure a baseline that is
over 1 million km long. There's no way the Moon can match that baseline, if
that's what you're looking for.

Labeyrie has proposed a 100-kilometer space-based 'Hypertelescope' that might
be able to directly see continents on planets up to 10 light years away. I
strongly suspect this is harder to pull off on the Moon, which has gravity,
vibrations, and every-changing thermal stresses messing up the interferometry.

I think you are confusing two different telescope projects. Liquid-based
mirrors are for optical telescopes, which aren't affected by radio
interference. While there are proposals for 20m-100m liquid mirrors on the
Moon, they have the big problem that they can't be pointed; it seems to be
more cool than useful, as the lack of research for projects on Earth like the
Large Zenith Telescope suggests.

While there's some advantage to using the Moon as a radio shield, the WP page
at
[http://en.wikipedia.org/wiki/Far_side_of_the_Moon](http://en.wikipedia.org/wiki/Far_side_of_the_Moon)
points out other difficulties in addition to the simple difficulties you
pointed out:

> Before deploying radio telescopes to the far side, several problems must be
> overcome. The fine lunar dust can contaminate equipment, vehicles, and space
> suits. The conducting materials used for the radio dishes must also be
> carefully shielded against the effects of solar flares. Finally the area
> around the telescopes must be protected against contamination by other radio
> sources.

As an alternative, the radio telescope can be built in lunar orbit, as, for
example, the OLFAR proposal at
[http://doc.utwente.nl/75270/1/Smallsat_final.pdf](http://doc.utwente.nl/75270/1/Smallsat_final.pdf)
. This seems cheaper and easier than building a farside telescope and support
infrastructure with the same capabilities.

------
FD3SA
Now that we're sadly past the era of "Big Science", we need to rely on
business models to get anything done. This includes trips to the moon.

I would argue though, that even if Big Science were to make a comeback, manned
Moon or Mars missions would not be an efficient use of those precious dollars.
There is much more pressing and productive research that is starved for
funding at the moment. Robotic space exploration is cheap and effective, and
scientifically far more useful.

I say this as one of the biggest space nuts I know. Let SpaceX and Bigelow
Aerospace do their thing and develop commercial space. We'll get our Moon
bases eventually, it'll just take time to grow the economic infrastructure.

