
How NASA and ISRO discovered water on the Moon - uncertainquark
https://jatan.space/how-nasa-and-chandrayaan-discovered-water-on-the-moon/
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unchocked
This is potentially the most important discovery in planetary science to date.
The reason, which is left until the end of this article, is that water can be
electrolyzed to yield hydrolox propellant, i.e. rocket fuel.

Rocket fuel dominates logistics in space. The tyranny of the rocket equation
is that it takes an exponential (literally exponential, not in the colloquial
sense) amount of fuel for a linear increase in velocity. This is why it's so
hard to go to Mars, and why we need to slingshot around Jupiter to go anywhere
else.

A source of rocket fuel above Earth's gravity well would break the tyranny of
the rocket equation, and serve as a stepping stone to other parts of the solar
system where water is abundant (i.e. Ceres, Mars). Until we have nuclear or
other exotic propulsion, water is the oil of space.

To paraphrase the lunar anthropic principle, if the universe had wanted
humanity to become a spacefaring species, it would have given us a Moon, and
it would have put water on it.

We're just scratching the surface of what these lunar water deposits mean.

~~~
PaulHoule
I see it the other way around.

Earthers find it hard to kick the idea that hydrogen and hydrocarbons are
fuels, but that is because oxygen is free on the surface of the Earth.

On Luna you might use that hydrogen to reduce hematite ore (found in
commercial quantity by astronauts) to Iron and Oxygen. Oxygen is like 7/8 the
mass of the fuel you need, you can make storage tanks, residential
neighborhoods, whatever you want out of steel if you can find a small amount
of carbon. You can recycle the hydrogen, it's not lost as it would be if you
burned it.

Lunar oxygen mining to refuel something like the SpaceX Starship faces tough
competition from Earth via the SpaceX Starship -- a 1990s study looked at 5
Earth to Mars mission scenarios with and without lunar materials and it wasn't
clear you could win with lunar oxygen.

The moon is close in configuration space to the Earth but far away in phase
space (including energy differences) NASA figured Apollo hardware could make
it to Venus

[https://en.wikipedia.org/wiki/Manned_Venus_flyby](https://en.wikipedia.org/wiki/Manned_Venus_flyby)

because you can use resonances around the moon to get a kick away from the
Earth as opposed to fighting the gravity well with a low-ISP rocket on the way
up and down from La Luna (no, atmospheric reentry on Earth is not "a problem"
but rather free delta-V and one hell of a preimage for your landing site)

A good main belt asteroid might be like Saudi Arabia but with the relative
proportions of sand and hydrocarbons reversed. You would be looking at a solar
5km/sec mission unless we got lucky and found a medium rare asteroid in the
"near earth" area.

Either way if you could build a chemical factory that can make things like
Kapton, Mylar or sheet graphene it shouldn't be that hard to handle giant
films to make a solar sail factory, install sunshades at L1, beam solar power
to moon bases at night, etc.

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jlgaddis
I know the guidelines on submission titles but this is a good example of how
one (missing/removed) word completely changes the entire meaning.

Perhaps the "How" should be added back in?

\--

Edit: The title has been changed. Originally, it was " _NASA and ISRO
discovered water on the Moon_ ".

~~~
EE84M3i
The "How" prefix was likely removed automatically during submission. dang has
confirmed there is a list of suffixes and prefixes that this happens with, but
it is not public what they are.

Edit: when I posted this the title was "NASA and ISRO discovered water on the
Moon"

~~~
umvi
I'm fairly certain the word "quietly" is automatically removed from submission
titles.

i.e. "Apple quietly drops case against X" => "Apple drops case against X"

However, I do think "quietly" provides extra context - it indicates Apple (in
this fictitious scenario) did not issue an official statement on what they did
or why; a 3rd party just happened to notice by reviewing public legal
documents.

~~~
pradn
It also implies a nefariousness that might not be appropriate.

~~~
mhh__
That's true but given that HN (via dang and the rules) often states that it's
supposed to be a more highbrow forum I think the subtleties of the title
should be left to the author of the submission.

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ricardobeat
> equivalent to at least 240,000 Olympic-sized swimming pools

For scale, the Earth has enough water to fill ~532 trillion pools.

~~~
antepodius
I wonder what the most efficient way to move bulk amounts of water out of
earth's gravity well would be?

It's probably mostly like any bulk freight lifted to orbit/escape: you could
pump it up space elevators, assuming you could get around the problems of
making those; An orbital ring is more physically plausible but has a much
higher initial outlay. Maybe you could accelerate a stream of it accurately
enough that the resulting hail of ice would reach, say, an earth-moon l3/4
point slow enough to be continuously captured and processed.

~~~
hinkley
One of the first futurists I read had a bunch of suggestions.

The most interesting was combining earth hydrogen with lunar oxygen freed up
by reduction operations on moon regolith.

More pedestrian was having ships sell their surplus fuel to a transfer station
in orbit. If your mission is completely nominal, you will have reaction mass
that you no longer need. Better to leave it for the next guy. I'm not sure how
you do that in a failsafe way, though. A burst line or a stuck valve could
ruin everybody's day.

It might require aux tanks that can be removed. For longer missions that might
be worth the complexity.

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GlenTheMachine
I’d like to correct the record here a bit. Although Clementine, the first
spacecraft to sense water ice on the moon, was indeed funded by NASA (and the
Ballistic Missile Defense Organization), it was in fact designed, built, and
operated by my senior colleagues at the US Naval Research Laboratory. For some
reason NRL rarely gets mentioned in this story even though it was our
spacecraft!

[https://www.nrl.navy.mil/clementine/](https://www.nrl.navy.mil/clementine/)

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causality0
It would be nice if we could stop moving the goalposts to give credit to our
favorite institutions. The Soviet probe Luna 24 in 1976 brought back samples
that were found to be 0.1% water. "NASA and ISRO are the discoverers because
they did the analysis without returning to earth" is such a cop-out.

~~~
xmprt
What did the Soviets do that was special? Did the samples from the Apollo
missions not show any water content?

~~~
causality0
Very little. What was there was dismissed as contamination, though a 2008
analysis showed small amounts of water locked inside pieces of volcanic glass
inside the Apollo samples. The recent tremendous emphasis on the Chandrayaan-1
mission is motivated largely by the failure of Chandrayaan-2.

~~~
uncertainquark
That's not right. The Chandrayaan 2 failure has nothing to do with the
Chandrayaan 1 discoveries. The lander of Chandrayaan 2 failed but it was not
tasked with a follow-up science of any of these water-related discoveries.
That is the job of the Chandrayaan 2 orbiter.

------
phoe-krk
[2019], [2009]

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garmaine
s/NASA and ISRO/Air Force/

Article can’t even get that part right....

~~~
notRobot
Do you have any sources to back this up?

~~~
garmaine
Well apparently I shouldn't have had the snark because even I couldn't get it
right. Should have been US Navy, which built and operated the Clementine
spacecraft which discovered large reservoirs of water on the moon. Follow-up
missions by NASA and ISRO confirmed this with better instruments, but it was a
military mission that made the initial discovery.

It's a bit of a contentious issue because loonies had trouble getting NASA
interested in the Moon again, and NASA rejected without evidence the notion of
cold trap volatiles. So they went around NASA and used defense money to get an
early version of Lunar Prospector launched, which was the Clementine mission,
and gave the evidence necessary to prove the value of the poles as potential
sources of in-situ resources.

(I got all the details of this from a talk given by a retired Air Force
general who was involved, so I mistakenly thought it was the Air Force that
ran it. Looks like it was actually a research division within the Navy.)

[https://www.lpi.usra.edu/publications/slidesets/clem2nd/](https://www.lpi.usra.edu/publications/slidesets/clem2nd/)

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praveen9920
Now I am worried about exploitation in the name of exploration by humans

~~~
hinkley
Would it be so bad if the mining was on the far side of the moon?

~~~
ffpip
It won't stop there.

~~~
hinkley
Could be. One of the things I'm worried about is that I think space mining
rhetoric has vastly underestimated the consequences of the dust, both on the
moon and in the asteroid belt. It might take generations to scrape the far
side of the moon, but the dust could be a problem within a few years.

