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Water on the Moon

By catdynamics on November 13, 2009.

Yup, the LCROSS crash did kick up some water.
NASA shows proof.



Splash

UV-spectroscopy shows H2O vapour.
About 0.1 m3 from a ~ 10m radius crater.

Not much, but definitely there.

I must day, the LCROSS "bombing" of the Moon is one of the worst handled NASA events in a long time, from a press perspective - very poor explanation of why NASA did this when it did, the likely scale of the event or indeed the analysis.

Lunar orbits are generally unstable - chunks of metal going around the Moon will generally end up crashing into the Moon - this is partly due to the Earth's gravity perturbing orbits, and partly due to the Moon's intrinsic lumpiness.
The issue with the LCROSS upper stage was to choose the time and location of the Moon impact to get something out of it - in this case the spectroscopy of the impact plume and the secondary plume.
Lunar impacts happen all the time, but they are transient events, so generally instruments are not targeting the impact as it happens. Hence the benefit of knowing when even a small impact happens, in advance.

The impact was small - there was no chance ever of a huge glowing mushroom cloud visible in amateur class telescopes, I did not get up to watch the event because I knew there would be nothing to see. The Moon's potential well is shallow and the upper stage is low mass as these things go.

The spectral analysis takes time, there was very little chance of "'live" results, the main issue is whether there would be no water, or a tiny bit - 100 liters from a 10m radius crater is dry, by Earth standards. The amazing thing is that there is any water at all.

So, cool result, terrible public relations.

NYT story

NASA press release

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astro

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I honestly dont believe that there is water under the lunar surface, how can water exist without atmosphere? there must be a catch in this story.

The earlier Chandrayaan claim based on 3 micron absorption was announced only after it was accepted by Science (along with papers that went back and confirmed it in Cassini and Deep Impact)

http://www.sciencemag.org/cgi/content/full/326/5952/568

This, as Steinn points out was badly handled PR wise. And once they dug that hole I suppose they had to put out a press release relatively quickly to say that it worked.