[HN Gopher] How NASA and ISRO discovered water on the Moon
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How NASA and ISRO discovered water on the Moon
Author : uncertainquark
Score : 148 points
Date : 2020-08-31 13:49 UTC (9 hours ago)
(HTM) web link (jatan.space)
(TXT) w3m dump (jatan.space)
| GlenTheMachine wrote:
| 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/
| praveen9920 wrote:
| Now I am worried about exploitation in the name of exploration by
| humans
| hinkley wrote:
| Would it be so bad if the mining was on the far side of the
| moon?
| ffpip wrote:
| It won't stop there.
| hinkley wrote:
| 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.
| sbmthakur wrote:
| What kind of exploitation?
| garmaine wrote:
| s/NASA and ISRO/Air Force/
|
| Article can't even get that part right....
| notRobot wrote:
| Do you have any sources to back this up?
| garmaine wrote:
| 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/
| jlgaddis wrote:
| 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 wrote:
| 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"
| generalizations wrote:
| In this case, it makes a dramatic difference.
| uncertainquark wrote:
| Yes, the the prefix was removed automatically even though my
| submission title was "The story of how NASA and ISRO
| discovered water on the Moon." Big difference indeed.
| umvi wrote:
| 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.
| oconnor663 wrote:
| It provides context but also emphasizes a particular
| perspective, that the subject "should have" or maybe "would
| have been expected to" announce what they were doing more
| prominently.
|
| The whole question of what is or is not news necessarily
| takes a certain perspective, though, so I guess this is
| always going to be a gray area.
| pradn wrote:
| It also implies a nefariousness that might not be
| appropriate.
| mhh__ wrote:
| 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.
| Aardwolf wrote:
| This is an interesting case where removing the word "How"
| makes the title _more_ clickbaity rather than less!
|
| In one case, it's an article about an amazing new discovery,
| in another case it's an explanation about the method of
| something we already know.
| phoe-krk wrote:
| [2019], [2009]
| ricardobeat wrote:
| > equivalent to at least 240,000 Olympic-sized swimming pools
|
| For scale, the Earth has enough water to fill ~532 trillion
| pools.
| pvaldes wrote:
| If there is any amount of water, It could be life or life
| remains trapped on it. Maybe not based in cells, but other
| forms like viruses... Hum.
|
| Is a really intriguing discovery. Maybe supporting the
| panspermia theory. Maybe leading to one of the biggest
| discoveries in our recent history. Maybe they could find
| several types of ice, if they came from different comets.
|
| I hope that we could analyze this water before to burn it as
| fuel.
| antepodius wrote:
| 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.
| mncharity wrote:
| A LEO-altitude-to-GEO space elevator has been proposed as
| possible with near-current tech... so perhaps a railgun pop-
| up to catch an elevator?
| unchocked wrote:
| No need to do that - Ceres is a water world and you can haul
| it into cislunar space from there.
| hinkley wrote:
| 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.
| achow wrote:
| Another perspective:
|
| USA uses 322 billion gallons of water everyday. [1]
|
| 240,000 swimming pool contains 120 billion gallons.
|
| USA would survive approx 8 Hrs on the moon.
|
| [1] https://medium.com/ensia/america-uses-322-billion-gallons-
| of...
|
| [Edit: Corrected. Thanks SamBam]
| SamBam wrote:
| I think you swapped the numerator and the denominator. If the
| US uses more water than is on the moon every day, how would
| it survive 2.5 days?
|
| (There's also some conversion problems because the article
| took the amount of water on the moon and estimated a number
| of swimming pools, and you've taken the number of swimming
| pools and estimated the amount of water. From the article,
| the moon has 600 billion kg of water, or 159 billion
| gallons.)
| unchocked wrote:
| 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 wrote:
| 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
|
| 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.
| Aperocky wrote:
| Either more fuel or patience, and I think patience is going to
| win.
|
| There are interplanetary 'highways' where you can spend barely
| any deltaV to go everywhere, provided you have patience.
|
| Probes are already transiting Earth and Venus multiple time to
| get slingshots to outer solar system.
|
| The ideal space base is a manufacturing hub in the asteroid
| belt. Where deltaV to go to anywhere else is ~0 and deltaV to
| launch stuff from base is also ~0. That's the only way to have
| star wars sized ship. Launching one from gravity well of the
| Earth or even Moon is just lunacy.
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