Klog

The Blog of Ken.

from October 9, 2009

"Bombing" the Moon? No. LCROSS in a nutshell.

Wooshy lines added for dramatic effect.

Wow. I am absolutely amazed at the number of soft, information-free stories that have circulated about the LCROSS satellite hitting the Moon. Let me throw out a couple of quick paragraphs to help my friends:

“Bombing.” No. We did not “bomb” the Moon. We did not use the Moon for some sort of military purpose or target practice. Here’s what happened.

About four years ago, NASA was finalizing the design a of a probe called the Lunar Reconnaissance Orbiter. The purpose of this probe was to go into orbit around the Moon and take high-resolution pictures of the entire surface. (Here’s one showing the landing site of Apollo 12. You can even see the trails the astronauts left!)

The designers went over on their weight allowance for the LRO and managed to finagle a bigger rocket that could lift a lot more. Rather than waste the extra weight allowance they now had, they put out a call to all the NASA research centers, asking them for ideas on how to fill the space. But it had to be something cheap, and something they could make fast, because LRO wasn’t going to wait around for them.

Ames Research Center came up with the idea of crashing a probe into a crater on the south pole of the Moon. Why? Well, there are some craters near the south pole that never, ever get any sunlight because their rims are so high. Previous probes have found evidence of ice in those craters, but nothing conclusive. But if we could crash a big heavy probe into one of those craters, it might cause a plume of debris to rise up, and we could look at that debris and tell if there was water in it.

Water is important. If we found a spot on the Moon with lots of water, we could use it not only for drinking and growing stuff, but we could break it down into hydrogen and oxygen. That would give us rocket fuel and something to breath. We wouldn’t have to keep bringing new air and water all the way from Earth. It makes a Moonbase much easier to build.

So LCROSS was launched with the Lunar Reconnaissance Orbiter, and last night, it met its intended end. The booster rocket that took LCROSS and LRO to the Moon crashed into the shadowy south pole crater first while LCROSS watched. Then four minutes later, LCROSS crashed as well. The LRO and several observatories on Earth recorded the event and analyzed the results.

And that’s the story. There was no military involvement, and we didn’t bomb the Moon. We crashed a probe into it, which is actually something we’ve been doing since the 1960’s (and a couple of times early on in the space race… not on purpose!) And if we do find water there? It will be a big step forward in our exploration of space.

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