LCROSS: Mission to HYPErspace
The LCROSS impact site seen from LRO
Early last Friday, the public and families of employees at Ames Research Center in California, where the LCROSS mission was conceived, built and operated, camped on the lawn in an all-night vigil. NASA’s educational outreach and public relations push about the pending lunar impact event was very effective, having reached a wide audience in the weeks leading up to the much hyped event. Alas, the promised giant plume of impact debris was invisible from Earth, leaving a receptive public feeling cheated and disappointed.
The understanding that a high-velocity impactor can yield important information about planetary composition and state is very old. The first probes to the Moon (both Soviet and American) were impactors. We know that when something strikes a planetary surface at high speed, target material is thrown up into space, some of it vaporized by heat generated in the energy of the impact. By studying this impact ejecta, we learn about the composition of the target object.
I didn’t post on it earlier, but as the LCROSS mission has successfully concluded, I think it is a good time to examine this mission, how it came about, and the lessons that hopefully it has taught NASA about public appeal and its involvement with space.
LCROSS was not originally a part of the robotic precursor program for lunar return. Initially, the Lunar Reconnaissance Orbiter (LRO) spacecraft was to be launched on a Delta II. By the end of 2005 it had outgrown its booster and was forced onto the much larger Atlas V booster where it had surplus payload margin. The Associate Administrator for the Exploration Systems Mission Directorate (ESMD) Scott Horowitz, decided to use this margin to fly an additional small spacecraft (called a secondary payload) that would address the raging debate about whether water ice exists at the poles of the Moon. Horowitz looked to NASA’s field centers for a small payload that would provide data about this contentious and nagging issue.
Although a variety of small missions were proposed, including survivable hard landers and small “hoppers,” the idea of slamming the Centaur upper stage into the Moon and examining the resulting ejecta plume was selected as LCROSS in April 2006. It was considered a low-risk, low-cost concept, as the used Centaur upper stage had no value and would have been steered into a solar orbit anyway. A small satellite was built to track the Centaur impact, measure the properties of the ejected plume and with luck, would “settle” the issue of water on the Moon.
A serious defect in this mission concept was that it presupposed that we understood the Moon well enough to identify in advance the most likely site for ice on the Moon. Lunar investigators knew from previous data that water ice, if present, was not present everywhere – it had a patchy, heterogeneous distribution because the permanent shadow around the poles (where the ice would be stable) is itself patchy. Moreover, the remote sensing data of the time was ambiguous as to which shadowed locales contained ice, if any.
In March of 2006, because of these uncertainties, those who had worked on the robotic precursor program laid out a sequential, incremental strategy to first map the deposits from orbit and identify the best candidate sites for ice. Following orbital mapping, we would soft-land with capable rovers and map and test the surface composition at a minimum of about 20 different sites. Although this strategy is more costly than a simple impactor mission, it would have provided us an unequivocal answer to the ice issue; we would know without doubt whether there is or is not water ice at the poles of the Moon. Moreover, rovers would collect information on the possible presence, physical nature and setting of other volatile substances (such as ammonia and methane) that have resource value. In other words, we would have collected the critical strategic information needed to locate, prospect, harvest and use lunar water.
Instead, the mission chosen and flown and heavily advertised by NASA as a citizen participation viewing event to find water on the Moon, could not answer key questions about polar water. If LCROSS detects water, we still won’t know where all the ice deposits are located, what other species might be present, what its physical state might be, and how it is distributed laterally and vertically in the surface regolith. If LCROSS detects nothing, it won’t prove that water doesn’t exist on the Moon, only that the wrong site was selected. In other words, after this mission, we will still know next to nothing about the material that will enable and advance permanent, sustainable economic presence on the Moon.
An impact plume wasn’t the only thing missing. Hopefully, NASA will recognize the real discovery of LCROSS – mission hype is a poor substitute for shortcomings in programmatic logic.
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The only justification I can imagine for you being upset is that the survivable hard lander or small hopper path was not taken as an add-on to the LRO mission, instead of the impactor that was selected. The rest of your arguments about knowing WHERE first to send a future lander/rover depend on the results of the LRO mission, which has just begun. Thus they would likely had fared no better than the impactor if they too were a just shot in the dark. So do not fret, as nothing precludes us from still sending a dedicated lander or rover after LRO data come in. As you did not specify the cost or schedule issues of the alternatives to the impactor, this reader is left with insufficient data to know if any of these alternatives could have met the LRO schedule constraints (which may have been “firm” at that time) or cost constraints (which no doubt had a desired cap). While I agree that LCROSS may have been overhyped, if NASA had NOT hyped-it-up, it would have been harrassed for NOT doing that — as NASA-Watch just did with regards to a recent sounding rocket mission from Wallops.
Comment by Ronnie Lajoie — October 12, 2009 @ 6:52 pm
Well, what happened to the rover that was supposed to be the LRO follow-on ? ( a rhetorical question )
Comment by kert — October 12, 2009 @ 7:42 pm
I can tell you that LCROSS generated a lot excitement. Our blog gets anywhere from 30 to 70 hits per day. Last Friday, we had over 300. The public is interested in space exploration.
Comment by Dave — October 13, 2009 @ 12:41 am
Ronnie,
You completely missed my point.
It’s not that NASA should have selected a hopper or other kind of hard lander (those had their own issues) — it’s that they chose to fly a mission that basically adds nothing to our strategic knowledge of the polar deposits while discarding entirely the robotic flight program that would have given us such information. They didn’t have to fly a secondary payload at all, so the LRO launch date (which was over a year late anyway) was not a constraint.
The mission has been advertised as big exploration event. I contend that it is not.
Comment by Paul D. Spudis — October 13, 2009 @ 5:13 am
Kert,
The money for the robotic program got absorbed into the Ares launch vehicle development.
Comment by Paul D. Spudis — October 13, 2009 @ 5:14 am
The data from the LCROSS mission is still coming in, so hopefully the next weeks or months of analysis will find something useful. While the mission may not have been as scientifically useful as the science community may have hoped, it did raise interest in the Moon by the general public; interest that hopefully won’t go away too soon in light of the lack of an obvious impact splash. As for the deferral of the Robotic Lunar Exploration Program (RLEP) program, now the much weakened Lunar Precursor Robotic Program (LPRP), that decision was indeed made to provide funds for near-term Constellation goals, and I too was not happy about that action. But we have a new NASA administration now and thus have an opportunity to seek to restore a viable robotic lunar exploration program (while waiting for human return). Let’s get some good LRO data, then finally get a U.S. rover to the Moon and down to a pole where it can drill for ice. So do not despair; the NEW Golden Age of Space Exploration is just beginning. Ad Astra!
Comment by Ronnie Lajoie — October 13, 2009 @ 11:20 am
Paul,
You make excellent points — ones that, I suspect, all but the most informed are not even aware of. That is a weakness of the current culture. Scientists and engineers need to get better at communications — with each other and with the larger public. There also need to be ways for scientists such as yourself to get greater attention from the larger world. Too many scientists and engineers dismiss this kind of work out of hand. You, thankfully, seem to be an exception. There are others. We need more.
Comment by Chuck Divine — October 13, 2009 @ 1:07 pm
[...] Read the full story. [...]
Pingback by Spudis: LCROSS More Hype Than Science | Parabolic Arc — October 13, 2009 @ 1:42 pm
[...] a comment » Still not much out of the LCROSS team, victims of “HYPErspace” to say the least. Let’s entertain ourselves in the intervening time with a Forbes.com [...]
Pingback by (Legally) Bombing The Moon « Maurizio – Omnologos — October 13, 2009 @ 5:50 pm
What’s your take on Arlin Crotts’ suggestion (particularly http://thespacereview.com/article/1485/1) that lunar water may be primordial?
Comment by Nels Anderson — October 14, 2009 @ 2:18 am
Yeah, it was rather disappointing. I was watching the live coverage and hoping to see *something*.
Still, apart from the broad criticism and uninformed complaints of ‘bombing’ of the Moon, I am hoping that soon someone will actually step up and try to explain why there was no impact ejecta. Because it does seem to me that if we expected something and didn’t get it, then that is of interest in itself.
If there was no impact plume, then what did we hit?
Comment by Paul — October 14, 2009 @ 3:33 am
Nels,
While I appreciate Arlin’s enthusiasm and tenacity in following up on the TLP problem, my suspicion is that the vast bulk of lunar water is from external sources, not the Moon itself. But the whole issue should be re-opened and examined afresh.
Comment by Paul D. Spudis — October 14, 2009 @ 5:19 am
Paul,
If there was no impact plume, then what did we hit?
There probably was an impact plume — it was just much smaller and much darker than had been supposed beforehand.
Comment by Paul D. Spudis — October 14, 2009 @ 5:20 am
Paul
I’m surprised at your attitude. As you will soon see LCROSS is a spectacular scientific success. The fact that the plume was not as pronounced as predicted IS significant. The data we are obtaining from these missions WILL be the justification for the landers etc. we all agree on. While I admire your forceful commentary, I believe you just may become an advocate.
Pete
Comment by Pete Worden — October 16, 2009 @ 7:36 pm
Pete,
Thanks for reading the piece and for your thoughtful comment. We simply disagree on the value of LCROSS, which I believe to be a “bargain basement” mission that ESMD used and is using as an excuse to ignore their duty to craft a robotic program capable of obtaining the data we need to use lunar resources. My position is that NASA as an agency has never embraced the “mission” of the Vision for Space Exploration — to go to the Moon and learn to use its resources to create new space faring capability. Because they have never accepted that charge, they do not see strategic knowledge about the Moon (particularly regarding resources and ISRU) as in the critical path. Hence, a real robotic program to get the strategic knowledge we need was dumped.
Comment by Paul D. Spudis — October 17, 2009 @ 5:49 am
I was listening to Science Friday and it got me thinking, why hasn’t anyone planed a mars rover like mission to take soil samples. If those rovers lasted 5 years with mars level dust storms and weaker solar energy a similar rover could give scientist 10 years of functionality.
Comment by Matt — October 19, 2009 @ 10:55 am
Matt,
Your question is excellent and should be directed to the Associate Administrator of NASA’s Exploration Systems Mission Directorate.
Comment by Paul D. Spudis — October 19, 2009 @ 11:39 am
Unfortunately, this all may not matter anyway. The Augustine report is about to come out, and the current Presidential administration and NASA leaders spend a lot of their time talking about the ‘flexible option’, one that mostly ignores the Moon and instead flies around space on “a three hour tour” to near-earth asteroids or the moons of Mars. It doesn’t help when an anonymous administration official asserts that options that include returning astronauts to the moon “are not sellable to the public or to the president.” Politics will trump any logical, methodical approach to space exploration as it always has. I suppose one could say the word ‘flexible’ could include the Moon, but I’m concerned that ‘flexible’ will be used by NASA to look a little at a lot, and come up with such an amorphous, open-ended do all for everybody plan that we wind up with nothing but view graphs for another 20 years. The path is so obvious and it goes through the Moon. It is painful to watch politics make a mess of it all. Maybe a more appropriate name for the new crew exploration vehicle should be the S.S. Minnow.
Comment by JohnG — October 21, 2009 @ 10:23 am
[...] weeks ago a crater from the LCROSS impact formed on the Moon. The pre-impact build-up had been sensational, but the actual event was largely invisible to observers on Earth. It was a [...]
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[...] Experiment” …; as one very leading lunar and planetary scientist, Dr. Paul Spudis, pointedly observed in his daily [...]
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