Date: September 6, 2011
Title: The LCROSS Revolution
Podcaster: Nancy Atkinson
Organization: NASA Lunar Science Institute (NLSI)
Link: http://lunarscience.arc.nasa.gov/
Description: Lunar CRater Observation and Sensing Satellite (LCROSS). The LCROSS mission was designed to search for water on the moon by sending a rocket crashing into the moon, causing a big impact, and creating a crater throwing tons of debris and potentially water ice and vapor above the lunar surface. This impact released materials from the lunar surface that were analyzed for the presence of hydrated minerals to tell researchers if water is there or not.
Bios: The NLSI brings together leading lunar scientists from around the world to further NASA lunar science and exploration.
Dr. Jennifer Heldman is a Planetary Scientist at NASA Ames Research Center and a member of the LCROSS science team.
Nancy Atkinson is a science journalist and is the Senior Editor for Universe Today.
Sponsors: This episode of “365 Days of Astronomy” is sponsored by Jason Ramboz. Twitter @jramboz. Web http://jramboz.wordpress.com.
This episode of “365 Days Of Astronomy” has also been brought to you by Distant Suns 3, the award winning personal planetarium software for the iPad and iPhone. Unleashing your inner astronaut since 2008.
Transcript:
Hi, this is Nancy Atkinson for the NASA Lunar Science Institute, and this week I’m reporting from the 2011 Lunar Forum at NASA’s Ames Research Center, where we’re hearing the latest in science findings from our missions to the Moon. Back in October of 2009 the LCROSS mission slammed a Centaur rocket booster into a crater on the south pole of the Moon, which produced a plume of ejecta that was observed by both the LCROSS shepherding spacecraft and the Lunar Reconnaissance Orbiter. Scientists are still studying the data that was gathered during the mission, but it has been one of the recent missions that has revolutionized our understanding of the Moon.
With me today here at the Lunar Forum is Dr. Jennifer Heldman, one of the scientists for the LCROSS mission. Thanks for being with us Jennifer, and could you tell us more about this mission and some of the latest science findings your team is working on?
Heldman: LCROSS was designed to answer one very specific question about the Moon and that is, is there water ice near the poles of the Moon. It is amazing that in this day and age we didn’t know the answer to that question. We had Apollo, but Apollo went to several equatorial sights, and since Apollo we’ve pretty much thought the Moon is very, very dry — bone dry has some have said, without any water and so going to the poles, we had to answer this fundamental question and lo and behold it turns out there’s actually a significant water sequestered in these permanently shadowed craters, so the bottom of these craters near the poles where there is literally no sunlight shining – so it is very, very dark and very, very cold. And this has completely changed our thoughts about the Moon because now we know that there are these vast reservoirs of water ice that are there. This is very important scientifically, very important for exploration and we’re really changing our understanding of the Moon.
Nancy: And you’re also finding answers water but some volatiles that were in the crater.
Heldman: Right, we are finding other things like CO, CO2, NH3, C2H4, a lot of hydrocarbons. So these are volatiles, which basically means they are gases which can condense out of very low temperatures. And so we are seeing these in the permanently shadowed craters. So it is water and a whole bunch of other stuff. And some of our science team members think of these permanently shadowed regions is sort of the junk yards of the solar system, because material comes in and is deposited and it is just so cold that those molecules don’t have any energy to get out again, and so there is this vast reservoirs all the stuff that is stuck down here in the poles.
Nancy: And if people can recall about the impact of LCROSS made back in 2009, people were kind of looking for a flash, there were ground-based observatories that were looking for the impact and it never really happened. But since then you’ve learned more about the plume itself, the ejecta. What is all telling us about the surface composition in that region?
Heldman: We have really great images of the impact plume from shepherding spacecraft LCROSS and also there is some tantalizing evidence from some of the ground-based observatories and in looking at the data we see plume itself, so we can see how quickly expanded. We are using that to constrain that amount of dust that got thrown up. We are looking at the spectra and that how we learned there was water ice there and all these other volatiles and gases. Also when we were watching, we were looking for a visible flash, sort of a bright flash of light in the visible part of the spectrum, and we didn’t see that. And that is really important because that is telling us that we hit into a sort of fluffy, less consolidated type of material. Supporting that, in the near infrared part of the spectrum, we did see a flash that was a little delayed and a little bit long and that also is more evidence saying, okay we didn’t just hit just a big solid rock or boulder, but we were hitting a sort of fluffy, porous type material. That is also supported by when we look at the data in the plume itself, we are seeing there are very fine particles and dust particles mixed in with the ice grains. So we are really disentangling what that plume looked like.
Nancy: You mentioned that your science team is still trying to milk the data that you have for all it’s worth. What are some things that you looking at?
Heldman: There is a lot of work sill going on. We had four minutes of data from the shepherding spacecraft we are still actively analyzing pretty much all of it. Some of the projects we are working on now, we are looking at the thermal images — there was thermal camera basically measuring temperatures on the shepherding spacecraft. So we can look at temperatures of that impact site, and we can actually see where the LCROSS Centaur impacted the surface of the Moon and we can see how it got warmer where it impacted and then how it cooled off. So different materials cooled off at different rates. And so we are using that to figure out, oh, there was still some ice at the bottom of the crater after we impacted. And that was affecting how it cooled off. That is one of the projects we are looking at. Another thing we are doing is doing some numerical modeling suing computer simulations to look at what happens to those ice grains once they got lofted up into the sunlight. Once they get into the sunlight they are going to start to sublimate and so they are going to get smaller and smaller and so then you create more water vapor. We are looking at those whole phase transition for these ice grains that have been down at the bottom of this crater and how they are behaving when they get into the sunlight.
Nancy: Jennifer Heldman from the LCROSS science team. Thanks very much for this science update.
Heldman: Thank you.
End of podcast:
365 Days of Astronomy
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