[X] My Assistant

[Guest_PhilCo126_*]

NASA taps (amateur) Astronomy community to help search for lunar water

Lunar CRater Observing and Sensing Satellite
LCROSS (Lunar CRater Observing and Sensing Satellite) is scheduled to launch with the Lunar Reconnaissance Orbiter,
known as LRO, aboard an Atlas V rocket from Cape Canaveral, Fla., in late 2008. After launch, the LCROSS shepherding spacecraft and the
Atlas V's Centaur upper stage rocket will fly by the moon and enter an elongated Earth orbit to position themselves for a rapid descent
into a permanently shadowed crater near the moon's south pole.
On final approach, the instrument-laden spacecraft and the upper stage will separate. They will hit the lunar surface about four
minutes apart. The spacecraft will fly through the Centaur debris plume and collect data before its own impact. The LCROSS impacts are
expected to be visible from Earth using 10-to-12 inch and larger telescopes.

http://lcross.arc.nasa.gov/

[nprev]

Yikes. Just gotta say that this has a MAJOR pucker factor from the description...four minutes is not a hell of a lot of time to relay data.

[rogelio]

Probably worrying too much, but how much precious lunar water will be wasted by this impact? Water that could be used some day by a polar moon base...

[djellison]

That's the whole point - we don't even know if there is any down there. It's by doing experiments like this that we can find out.

They're expecting to kick up perhaps 1,100 tons of regolith with the impact, and there's supposedly 6 billion tons of the (H2O) stuff down there. 0.000183 percent of the water, if it's there. Personally, I'm quite skeptical about it.

Doug

[nprev]

High risk for a potentially high payoff, I guess...but damn, that's a tight margin.

[mchan]

Yikes. Just gotta say that this has a MAJOR pucker factor from the description...four minutes is not a hell of a lot of time to relay data.

Kind of like a Ranger mission.

[nprev]

Yeah, but even more so. All Ranger had to do was snap pics; LCROSS is performing analysis (spectroscopic, I assume, but if so why does it have to fly through the Centaur's impact plume?) Almost sounds like it has some kind of onboard sample acq/analysis instrument, but can't see how such a thing would produce results in such a brief time.

EDIT : The payload consists of "cameras and spectrometers" (note the plural). Sounds like a full multispectral campaign in real time; every segment of the downlink chain better be at 100%.

[centsworth_II]

At least the nearness of the Moon will allow for
a much larger and faster data stream than that
from planetary missions. (I assume).

[nprev]

It should; at the risk of sounding like a complete jackass, I think that one of our esteemed comm experts stated that the bit rate is proportional to something like the fourth power of the distance.

Sure would like to know which DSS will the the primary for the encounter, though; the rain in Spain has caused us massive pain, in the past

[tty]

Maybe it could relay the data to LRO?

[djellison]

It doesn't need to - and nor could it anyway -neither LCROSS or LRO are equipped with appropriate hardware to do that.

Yes -it's a short period of time. So what? If it works, it works. Get a couple of DSN's pointing at it, good data rates are planned they'll have a few months of operations practice before the impact anyway. I'm not concerned about it to be honst.

Doug

[nprev]

Well...the coolness factor is undeniable. Gonna be one hell of a stunt if they pull it off!

[dvandorn]

Besides, it's not like there's a long cruise phase during which problems might crop up, right? Last I saw, the Moon isn't more than a few days away (unless you take a *real* slow route).

-the other Doug

[djellison]

Actually LCROSS does take a long route. It's a couple of months longer than LRO, involving Lunar flybys to target for the south pole.

Doug

[mchan]

LCROSS includes live RocketCam on the way down

Putting that on my calendar for next year.