Guide to the Cosmos, gold, New Scientist

Monday, January 11th, 2010

As of today, I’m on a podcast! Check out “Guide to the Cosmos,” a podcast hosted by Dr. Robert Piccioni, at www.guidetothecosmos.com. It was actually Christmas Eve Day when we recorded this interview over the phone, and it’s a two-parter. The first part, in today’s episode, is about water on the moon, and I talk all about the recent discoveries by Chandrayaan-1 and LCROSS. The second part is about the origin of the moon, and that part of the interview will air in February.

The audio part of the podcast is actually on a different site, called WebTalkRadio. You can go to their main site, www.webtalkradio.net, and then look for “Guide to the Cosmos” under the “Show podcasts” tab. But I’ll make it easy for you and give you a direct link. Dr. Piccioni also puts some images up on his own website to go with the podcast, which you can look at here as you listen to the interview.

When I recorded the interview I did not know which images he was going to have up on his website, so I wasn’t able to refer to them directly. Let me fill in that gap here. Image #1 shows the impact plume from LCROSS’s crash into the Cabeus crater.

Cabeus impact plume

This cloud of debris was not visible from Earth. The photo was taken from the “shepherding satellite” that passed directly overhead and crashed into the moon 4 minutes later. The spectrometers on the shepherding satellite analyzed both the absorbed and emitted light from this cloud to look for traces of water and other compounds. Image #2 is just a pretty picture of the full moon, nothing else. The LCROSS impact happened way down at the bottom of that picture, in the bumpy area around the south pole. Image #3 is a “wiggly line” from the ultraviolet and visible spectrometer.

Spectrum showing sodium emission line plus something interesting

Interestingly, this is not the data set that Tony Colaprete, the main project scientist, has talked about the most. Unlike the near infrared spectrometer, whose readings they understand pretty well and which show definitive evidence of water, the UV/VIS spectrum requires more interpretation and they are just beginning to work on it. The peak on the right is actually not water but sodium. (This emission band looks yellow to the naked eye, and explains why a sodium lamp is yellow. See this Wikipedia entry to read more about it.)

You can also see two shorter peaks on the left that have not been identified yet. At the AGU meeting in December, Tony said they think that one of them could be gold! Yes, gold on the moon. You read about it here first.

Back in the days before Apollo went to the moon, there was a slightly kooky scientist named Tommy Gold who said that the moon was covered by a layer of dust so deep that any spacecraft that landed on the moon would just sink into it and never be seen again. Fortunately, this didn’t turn out to be the case, but for a while NASA had to take the possibility seriously, and his hypothetical surface layer became known as “Gold dust.” But now lunar gold dust may take on a whole new meaning!

I did not report on this earlier (“LCROSS Strikes Gold!”) because they really don’t know what the peaks are yet, and so Tony’s comment was at least partly meant in jest. If they ever get more serious about it, I’ll be sure to let you know.

Last month I wrote an article for New Scientist online about the moon sessions at the AGU meeting, called “Are We Looking in the Wrong Places for Water on the Moon?” This was a very ticklish article to write, but I was happy with it in the end. Basically, the story is that one of the instruments on the Lunar Reconnaissance Orbiter (LRO) has been seeing lots of indications of water in places where it isn’t supposed to be.

LCROSS went to a permanently shadowed crater because that is where theory says that lunar water, if it exists, should concentrate. It went to Cabeus, in particular, because that is where the Lunar Exploration Neutron Detector (LEND) on LRO saw the highest concentrations of water. But what’s interesting, and controversial, is that LEND has seen no correlation so far between permanent shadowing and hydrogen deposits! There are other regions with just as much water as Cabeus that aren’t in shadow.

What made the article ticklish to write is that there are some people who frankly don’t believe the LEND data yet. I tried to hint at this without pouring oil onto the fire. But there are three groups–one in Russia, two in the U.S.–who are working on the LEND data and they all are saying pretty much the same thing. You can’t just ignore this fact and pretend it isn’t there, while at the same time singing the praises of LCROSS and the LRO camera and the other experiments on LRO. That’s why I felt it was important to write this article, even if the jury is still out on what the results mean.

In a blog I think I can be more adventurous than I can in print, so I’ll hazard a guess as to what it might mean. The LCROSS results are hinting that there is way more water than you can produce by bombarding the moon’s surface with the solar wind–some of the water has to be from meteoroids or comets. LEND can see beneath the surface, and Igor Mitrofanov, the principal investigator for LEND, says that he thinks they are seeing deposits of hydrogen that lie beneath the surface, covered by a layer of dry soil. Putting two and two together, I think that the water is delivered by meteoroids/comets, and is then buried by some process we don’t understand yet (or maybe it’s just in a sufficiently thick layer to begin with?). Once it’s buried, it doesn’t need a permanently shadowed crater to keep it from evaporating. Sure, it might be associated with a permanently shadowed crater, but really any crater will do. Or maybe even something that isn’t a crater! One of the most puzzling things about the LEND data was that one of the hydrogen deposits seemed to be on one side of a mountain range. But maybe that makes sense, if the mountain range was created by the meteoroid/comet impact.

Well, this is just my feeble amateur speculation. The specialists will, of course, hash it out and either come up with an explanation, or agree to disagree. One thing that’s pretty certain is that there is a lot we don’t know yet.

Tags: Chandrayaan-1, hydrogen, LCROSS, LEND, lunar origin, New Scientist, podcast, Robert Piccioni, Thomas Gold, water, WebTalkRadio
Posted in Media, Meetings, Missions, NASA, Science, websites | 2 Comments »

LEAG Conference, part 1

Thursday, November 19th, 2009

I’m back from the Lunar Exploration Analysis Group (LEAG) meeting in Houston, which ran from Monday through Wednesday this week. There was plenty of talk about LCROSS, which one member of the LCROSS science team calls “the little mission that did,” and also lots of discussion about the future of lunar exploration. The big theme of the meeting was sustainability: How do we go back to the moon in such a way that we can keep on going there indefinitely? Many, though not all, of the participants interpreted that question to mean: How can we make the moon economically viable? Of course, the LCROSS mission has a great deal to say about that.

Of course, the talk I looked forward to the most was by Tony Colaprete, the principal investigator for LCROSS. He gave only a few more scraps of information beyond what was reported in the news conference last Friday, but nevertheless I felt that the scraps fit together into an interesting story, which I wrote for the New Scientist website. You can find it here. I concentrated on the discovery of other volatiles besides water, because that was clearly what most interested the people I talked with.

I had to do a little soul-searching, because I go a little farther in the article than Colaprete would go in saying where the water and volatiles probably came from. But isn’t that my job as a journalist? If the experts are pretty sure about piece A, and they are pretty sure about piece B, and if there is only one way that piece A and piece B fit together and everybody knows it, shouldn’t I tell the public about that? Or do I have to wait until, ta-dah!, they hold a press conference and say they are ready to draw conclusion C?

Anyway, there were lots of other interesting and fun things at the meeting. For my blog I will concentrate on personal impressions rather than scientific news.

First, one thing I really loved about this meeting was how much joking and camaraderie there was. I don’t know whether it’s because it is a small enough community that everybody knows each other, or because certain people who are leaders in the community set the tone with their irreverence, or whether it’s just because everyone was in high spirits over the LRO and LCROSS results (and let’s not forget the Chandrayaan-1 results before that). Or maybe it’s just because geologists and planetary scientists are by nature goofy people.

Anyway, the big running joke at the meeting was Larry Taylor’s shorts. After the LCROSS press conference, he was quoted by the New York Times saying that he would have to “eat his shorts.” He was one of the scientists during the Apollo days who came to the conclusion — with good cause, I might add — that the moon rocks were “bone dry” and did not have a scrap of water. He told me that his grandfather used to say that he would “eat his shorts” if he were proved wrong, and so Larry told the newspaper reporter that he would have to eat his shorts now that water had been found in abundance. He had no expectation that this quote would be featured prominently in the Publication of Record. But then he got about 50 e-mails the next day asking if he would have a side of fries with the shorts, and what else he wanted to eat along with them. At the meeting several speakers ribbed him about this, and he finally said that he would eat them if they were served with a bottle of Guinness. Well, with unbelievable alacrity, a four-pack of Guinness beer materialized at the front of the lecture hall! I’m afraid I am not sure whether he eventually made good on his promise (I rather doubt it), but it shows how much fun people had at this meeting.

One of my favorite moments from the meeting was listening to a conversation between Wendell Mendell, another scientist who has been around since the glory days of NASA in the early 1970s, and Igor Mitrofanov, who is sort of his Russian equivalent. They swapped stories about the beginning of the Space Age. Mitrofanov described how when Sergei Korolev wanted to launch the first Russian satellite, he went to the Academy of Sciences, who of course loaded it down with more and more things that they wanted the satellite to do. It looked as if it would take forever, and Korolev was worried that the Americans would launch a satellite first. So he went to Khrushchev, the leader of the Soviet Union, and asked if he could launch a satellite that would just go beep beep beep. Khrushchev said sure, and Sputnik was born. Khruschchev didn’t think much of it, but when Sputnik flew in October 1957 and he saw how panicked the Americans were, he called Korolev back into his office and said, “I want another satellite by November!” (The over-complicated Academy of Sciences satellite did finally get launched, Mitrofanov said, but it was their third satellite.)

Mendell said that President Eisenhower was actually glad to have the Russians launch the first satellite … until he saw the furor that it caused. He wanted to be able to fly satellites over Russia to take spy pictures, because the U-2 airplanes that were doing this job were at risk of being shot down. If the Russians launched the first satellite, they couldn’t very well complain when the Americans launched one of their own. Nice plan, until everyone in the U.S. got hysterical about Sputnik, and the U.S.’s first attempt at a satellite launch blew up.

I guess these stories are probably pretty well known, at least the U.S. side, but I loved the idea of these two scientists, once separated by an Iron Curtain, being able to talk and laugh about these things.

More meeting thoughts and recollections in my next post …

Tags: Chandrayaan-1, Dwight Eisenhower, economics, humor, Igor Mitrofanov, LCROSS, LRO, New Scientist, Nikita Khrushchev, Sergei Korolyev, Sputnik, sustainability, Tony Colaprete, Wendell Mendell
Posted in Just for Fun, Meetings, NASA, Science | 4 Comments »

Water on the Moon — Bring your Buckets!

Friday, November 13th, 2009

As usual, the LCROSS press conference had a lot of Power Point slides, but probably the most memorable thing about it was an empty 2-gallon industrial bucket. Tony Colaprete, the lead scientist for the mission, said: “I’m here today to tell you that yes, indeed, we found water on the moon, and we didn’t just find a little, but we found a significant amount.” Then he held up the bucket. ”In the 20-30 meter wide impact crater that LCROSS made, we found about a dozen of these 2-gallon buckets. And that is probably a lower bound.”

Let me back up and give a little bit of context. Earlier missions, Clementine and Lunar Prospector, had found evidence for water ice but no direct proof. This year, three different missions simultaneously reported proof of water ice, because they detected not just the spectral signature of hydrogen (H) but also the hydroxyl molecule (OH). [It doesn't take too much knowledge of chemistry to see that hydrogen, H, plus hydroxyl, OH, equals water, HOH.] Not only that, the hydroxyl comes and goes over the course of a lunar day, which suggests that there is some chemistry going on at the moon’s surface. Carle Pieters, the principal investigator for the Chandrayaan-1 mission’s Moon Mineralogy Mapper, estimated that you could get a liter of water from a football field-sized area of the moon’s surface. This was exciting news, but as a reality check, it still makes the moon drier than Earth’s driest desert.

LCROSS has found an oasis in the desert. It was targeted for a specific crater near the south pole, Cabeus, where remote sensors had detected a high concentration of hydrogen. It excavated a 30-meter crater, only a third the size of a football field. Within that region, it dug up not just a liter of water, but 100 liters. Again, for context, one reporter asked Colaprete how this compares with Earth’s driest deserts. He said, “If you stand on that beach [the sandy spot where LCROSS impacted], I can say that it is wetter than some deserts on Earth.”

Does this contradict the Chandrayaan-1 findings? Of course not. It just re-emphasizes how little we know. Chandrayaan-1′s measurements were taken over a broad swath of the moon. By comparison, LCROSS is just looking at a tiny pinprick on the surface. Also, Chandrayaan-1 was measuring only the water that is right at the surface, up to a few microns deep. On the other hand, LCROSS excavated to several meters below the surface. To me that was one of the most exciting things about LCROSS; unlike measurements from orbit, it really sees what is underground. (However, it turns out that I was not entirely correct when I thought that LCROSS would be the first mission to do this. Radar measurements can penetrate one or two meters. Chandrayaan-1 carried a radar instrument on board, but those results have not been published yet. When they do get published, Paul Spudis promises me that they will be good.)

So basically, we now have one data point where we had zero before. We know that at one particular location, we have found an oasis. It remains to be seen exactly how concentrated the water ice is there, how heterogeneous it is, how hard it is to find other areas with lots of water, how deeply it is buried, etc. Not only that, there is a whole new suite of questions: How does water get to the moon? Once it’s there, how does it get transported to the poles? There are lots of theories, and at this point absolutely no way to choose among them.

What we have here is the appearance, in less than two months (since Pieters’ paper), of a whole new field of science that didn’t exist before: lunar hydrology. The next step, of course, will be for the LCROSS team to continue analyzing their data and nail down the concentration of water at their impact site. Also, LRO (the Lunar Reconnaissance Observer) will continue making large-scale observations  to figure out where else on the moon we might find water. But then, if we’re really serious about following up on this discovery, the next step needs to be a lunar rover (or even several of them) to poke around these permanently shadowed craters and start answering the questions in the previous paragraph.

There was one other very interesting thing mentioned at the press conference, which Colaprete was clearly eager to say more about but he just doesn’t have the data yet. LCROSS found lots of other volatile elements in the debris plume and/or the vapor cloud released by the impact. These may include:

• carbon dioxide
• methane
• methanol
• ethanol
• ammonia
• other organic molecules

The case for these is not as clear yet as the case for water. Colaprete said that it is absolutely certain that some of them are present, but they can’t yet pin down which ones and in what amounts. The science team is going to continue working hard to answer those questions, but they felt that the detection of water was so clear and of such overriding importance that they voted to go public with it now (instead of waiting another month, as per the original plan). But still, stay tuned for news about these other volatile compounds, because this story ain’t over yet.

Tags: buckets, carbon dioxide, Carle Pieters, Chandrayaan-1, hydrology, LCROSS, LRO, methane, oasis, Paul Spudis, Tony Colaprete, volatile compounds, water
Posted in Media, Missions, NASA, Science | No Comments »

LCROSS Results Tomorrow

Thursday, November 12th, 2009

Last month the LCROSS satellite crashed into a crater near the Moon’s south pole, in an experiment designed to look for water ice. At that time the principal investigator, Tony Colaprete, said that they would probably announce the results from the mission within two months. Well, they’ve beaten that timeline by a month. Tomorrow there will be a press conference at NASA Ames at 9:00 am Pacific time (12 noon Eastern time) to announce the first findings.

As I wrote in my previous post, the LCROSS impact was sort of a dud from the point of view of public relations.  It was not possible to see the debris plume from an amateur telescope, as the mission planners had hoped. Nevertheless, the instruments on the spacecraft definitely did see the debris. Thus, from an engineering point of view, the mission was a success. They landed the spacecraft where they wanted to land it and they got data.

So that leaves one more question: Was the mission a success scientifically? And in particular, did they find water? That’s the question that I am almost certain will be answered, one way or another, tomorrow. And of course it is the most important question from the viewpoint of future exploration of the moon.

I don’t have any inside information, but Tony Colaprete did say this in an e-mail to me a couple weeks ago: “We have a wonderful data set … It amazes me a little more each and every day.” Read into those tea leaves whatever you will!

In related news, Colaprete and other members of the LCROSS and LRO missions are going to present their early results next week in Houston, at the annual meeting of the Lunar Exploration Analysis Group. Of course the press conference tomorrow will cover anything really big and important, but I’m sure there will be many more details and more discussion at the Houston meeting.

Fortunately, New Scientist has commissioned me to write an article about the status of the lunar water question, taking into account all the results that have been announced this year, from Kaguya to Chandrayaan-1 to LRO and LCROSS. I will attend the Houston meeting, and this will give me a chance to do lots of interviews.

I think we are now at a crossroads in lunar exploration. We’ve gotten a big influx of new data this year, with tantalizing signs that there is more water than we expected on the moon. Now is the time for planning the next steps. Do we shrug our shoulders? Do we invest $3 billion more into the NASA manned flight program, as the Augustine Commission suggested? Do we plan new robotic missions? If so, what should they do?

Lots of questions. Hopefully I’ll find out a few answers, starting tomorrow.

Tags: Houston, LCROSS, LEAG, New Scientist, Tony Colaprete, water
Posted in Media, Missions, NASA, Science | No Comments »

Craters in the Dark …

Friday, October 9th, 2009

The moon has two new craters in it today, courtesy of NASA and the LCROSS mission. Along with hundreds of thousands of other people, I got up before 4:00 this morning to watch the live coverage of the impact. It was … well, anticlimactic. But I’ll get to that below.

It gave me an amazing sense of deja vu to see live coverage, from a NASA spacecraft, of the moon getting larger and larger. It’s been only 37 years since the last time … Welcome back, moon! Nice to see you again!

Impact site is below and to the left of the prominent crater (center). NASA photo.

Of course, this was very different from the Apollo missions. The difference was especially apparent when the second spacecraft (the “shepherding satellite”) hit the moon. There was no astronaut saying from the moon, “Tranquillity Base here. The Eagle has landed.” Instead, we got the flight controller saying from a control room in Mountain View, California, “Flight shepherding spacecraft impact, stations report LOS [loss of signal]. Last tracking at 11:35:35.054 seconds.” And then, that was it. From the operational point of view, the mission was over. The controllers got up, exchanged high fives, and started milling about the control room. If this had been a manned mission, or even a soft landing of a robotic mission, the work would be just beginning. It was weird for it to be over so abruptly.

Just a few seconds earlier, there was an interesting comment from the science control room: “We confirm thermal signature of the crater over mid-IR camera.” For anyone wanting live, real-time science, this was it. As the chief scientist, Tony Colaprete, explained later in the press conference, the infrared camera saw a distinct bright spot, a little over a pixel wide, that was the hot, newly formed crater from the Centaur rocket impact. He was clearly jazzed about this detection, which they weren’t sure that they were going to be able to make. The ultraviolet spectrometers also got excellent readouts that should contain lots of information about the material that was thrown up by the impact. But Colaprete wouldn’t say, or even speculate, what they have seen yet. The main thing he wanted to emphasize was that the instruments worked and they got the data they wanted.

The press conference was kind of interesting to watch because it was clear that the story the media found interesting was exactly the opposite of the spin that NASA would like to put on the landing. None of the four speakers mentioned this, but it was clearly written on one of the slides taken from an Earth-based telescope: No plume detected.

Reporters are trained, of course, to look for the elephant in the room that nobody is talking about. They homed in on what Tony Colaprete, Jennifer Heldmann and Michael Wargo weren’t saying — the fact that none of the ground-based telescopes were reporting any visual evidence of the impact. I really think that the scientists should have acknowledged this up front. A lot of the publicity and a lot of the planning of the mission was built around the premise that the debris plume would be visible from Earth, certainly through the big professional telescopes in California and Hawaii, but even through a 10-12 inch amateur telescope. But it wasn’t. I think that the reporters were right to question the scientists on why no plume was seen (yet) and what this might mean.

However, though “no plume” might be the big news story at the moment, it is very far from the end of the story. The scientific work of the mission is just beginning. The press conference was held two hours after impact. But the more relevant time frames are two days (the time that will be spent with the full science team at NASA-Ames collecting data), two weeks (when they will meet again and start drawing their initial conclusions), and two months (when they are likely to make a public announcement of the results). Tony Colaprete and Michael Wargo made the following very important points:

1. It is not clear yet that the plume wasn’t detected. Further image processing could reveal that it was there, but fainter than expected. “Gray on black,” as Wargo said.
2. Even if the plume wasn’t detected, the crater was detected, and it was about the expected size. Its thermal signal will give a lot of information about what was at the impact site.
3. Colaprete kept coming back over and over to the point that “spectra are where the science is at.” The spectrometers are more sensitive than the cameras, and they tell you what the chemicals are that you are looking at. For the most part the readout is not instant (although Colaprete did talk about a clear sodium line).
4. Finally, Wargo reminded the reporters that this was an experiment. An experiment, by definition, is something whose result you don’t know in advance. You might have a prediction or a theory, but until you do the experiment you just aren’t sure what is going to happen. So the plume was smaller or darker or less dramatic than expected. That will still tell us something.

So the press conference was an interesting clash of cultures. The media like pretty pictures, big explosions, and dramatic discoveries. They don’t like to wait. The scientists, as Jennifer Heldmann said, like “squiggly lines” (like the output of a spectrometer). They understand the value of patience and gathering all the evidence before you reach a conclusion.

If you want to know whether LCROSS saw water ice on the moon, your best bet is to stay tuned. The answer is likely to come out at the American Geophysical Union (AGU) meeting in December, in San Francisco. I’ll be there!

P.S. Maybe I was wrong about the media spin being different from the NASA spin. Here’s a mainstream media article that barely mentions the lack of a visible plume.

Tags: anticlimax, deja vu, ice, impact, LCROSS, plume, science culture, spectrometer, squiggly lines
Posted in Media, Missions, NASA, Science | 1 Comment »

“That’s Daddy’s rocket!”

Tuesday, August 25th, 2009

In an earlier post I wrote about the LCROSS mission, which is due to make its crash landing on the moon on October 9. (Mark your calendars!) In July I talked with Tony Colaprete, the Principal Investigator for the mission. I apologize if there is a bit of unevenness in this interview, because I have cobbled it together from three sources — our conversation at the Moon Fest, an e-mail, and his presentation at the Lunar Science Forum. Answers have been edited for length but I have tried to preserve Tony’s wording.

Tony Colaprete (NASA photo)

DM: You told me that you were born the week before the Apollo 11 landing. So, happy birthday! How big an inspiration have the Apollo missions been to you?

TC: I was born July 16, 1969, the day Apollo 11 launched. My father was heavily involved in the Apollo program, and one of my early childhood gifts was the classic Snoopy dressed in an EVA suit. So, yes, the Apollo mission was a huge influence, not only because they were so amazing but also because of my father’s involvement. … I am amazed to think that the folks who did Apollo were on average around 25 to 27 years old! The commitment, devotion, and guts those people had is inspiring.  I just hope I can do things half as right as they did for the Apollo program.

DM: When and how did you decide that you wanted a career in space exploration? How did you prepare for it?

TC: When I graduated from high school I knew I wanted to either go into the sciences or art. Luckily for us all, I decided to go into the sciences. … Very early on, though, I loved being in the woods near Boulder, Colorado, where I grew up. I would go for hours by myself and just watch what went on around me. So very early on I knew I loved systems, how things work together and influence each other … I still do.

I worked on instrumentation at the University of Colorado through the Space Grant College and the Laboratory for Atmospheric and Space Physics for a few years after getting my bachelors degree in physics. I was taking a few graduate classes (including my first planetary atmospheres class, taught by a very inspiring David Grinspoon), when I realized I wanted to pursue a graduate degree in planetary sciences. Luckily, CU is a great place to do that!

While I was doing my graduate work I continued to work on instrumentation for sounding rockets, space shuttle flights, and small spacecraft. This combination of science and engineering (again, systems!) was key, I think, to helping me get where I am now.

DM: How did the idea for the LCROSS mission come about?

TC: When LRO moved up to a bigger rocket, they had room for an extra 1000 kilograms on board, and a call for proposals went out for a co-manifested mission. And by the way, they said, you have only 2½ years to get it done, and you can’t spend more than $80 million.

When the call was announced, we [at NASA Ames] formed a “Tiger Team” to come up with ideas. Early on in the process we considered an impact mission, but I concluded that with only 1000 kilograms to work with, the impactor mass would be too small.

Another person in the group, Geoff Briggs, suggested using the spent upper stage of the launch vehicle. He has since said that he got the idea from someplace else. I ran some numbers and convinced myself that an impact by an object of about 2000 kilograms would produce a cloud observable from earth.

At about the same time, Northrop Grumman submitted a [proposal] that was also using the upper stage and also had a small shepherding satellite that could make observations. An engineer on the Tiger Team saw the idea and told me about it. We had a couple Northrop Grumman scientists come up and we discussed our ideas and the rest was history. So I don’t think it was any one person’s idea, but just enough people with the same idea!

In the end, LCROSS was selected out of 17 proposals. We cheated the 1000 kilogram limit — it’s 3200 kilograms, because we held on to the spent Centaur [rocket stage], which is about 2300 kilograms.

DM: Have you ever watched a launch in person before? If so, how was it different, knowing that it’s your own experiment that is going up?

TC: I’ve flown payloads on sounding rockets and shuttle flights, and have seen those go before. This Atlas moved so slow at first! I thought to myself, “You’d better pick up some speed or you’re not going to make it!” The sounding rockets and the shuttle use solid fuel, whereas the Atlas V is all liquid — it’s a big difference!

My biggest concern at launch was whether we could get off on the 17th or the 18th [of June], because those two days result in very good impact observing conditions for the continental U.S. The 19th was not so good, and on the 20th [there were no good times] at all. So I was very glad the weather broke in time for us  to go on  June 18.

DM: Have there been any exciting moments since the launch?

TC: I held my breath when we turned on the instruments for the first time. That was a moment of sheer terror and anxiety for me. Also, I’ll hold my breath again on August 1, when we turn them back on. Radiation and vacuum can have effects on detectors, so they always degrade over time. Once we know that they are working, I will be very confident that the payload will survive until the impact with the moon. [According to the mission page, the checkout of the infrared cameras and spectrometers on August 1 went very well. They took spectra of Earth and -- stop presses! -- detected oxygen, water, and vegetation! -- DM]

DM: What are you expecting to see when LCROSS hits the moon?

TC: There are a couple different models of how the water gets to the south pole and two different predictions for how it is distributed. We describe them as the smooth versus chunky models. In the smooth model, the ice is uniformly distributed on the scale of this room, with about a 1 percent concentration of ice. If that model is correct, LCROSS will have very good chances of detecting it. LCROSS should be sensitive down to concentrations of half a percent.

However, if the ice is chunky, with smaller pockets of up to 10 percent ice, then we might have a 10 percent chance of hitting something. If we hit one of the “peanuts” in the chunky peanut butter, we’ll know. This would immediately distinguish between the two competing models.

My biggest fear is that we won’t see anything — that it will be a dud. But even in that case, then we’ve learned that the distribution isn’t smooth. That is important to know, because it means that your next mission [i.e., a lander to search for ice on the ground -- DM] had better be mobile.

DM: How does the LCROSS mission compare with other spacecraft that have crash-landed on the moon (Lunar Prospector, the European SMART-1, and the Japanese Kaguya)?

TC: None of those other missions were designed as impactors. The biggest difference is that they typically hit the moon at a low, grazing angle, because they were in orbit around the moon. LCROSS is not, it’s in orbit around the Earth. [This is a rather non-obvious fact that is illustrated on the flight director's blog at this link. LCROSS doesn't "go to the moon." It goes into an orbit around Earth that is the size of the moon's orbit, and then the moon just runs into it! - DM] So it will hit at a very steep angle, around 85 degrees. Also, we’re bringing quite a bit of mass. So those missions can’t be compared to LCROSS for visibility, size, and impact angle.

DM: How big a crater will the LCROSS impact make?

TC: We’ve done simulations using Apollo-era technology, and we expect the crater to be about 20 meters wide — the size of a tennis court. We expect the plume to contain about 300 to 400 metric tons of material.

DM: On the LCROSS website you have a list of several possible target craters. Do you have a favorite on this list?

TC: Faustini would be my preference. It’s a very old, large crater, so the material in there has been in shadow for a very long time — around two and a half billion years. We want to hit somewhere that is flat and fluffy, not blocky and steep. One thing against it is that it’s right on the limb of the moon. So the ejecta have to go up 2 kilometers in order to be illuminated by the sun. In some of the other target craters, the ejecta only have to go up about 500 meters. But for earth observers, a position on the limb means that you get high contrast [against the darkness of space -- DM], and that’s good.

DM: I think it’s interesting how you have been able to use the results of other recent missions to narrow down the list of targets for this mission. Can you talk a little bit about  the synergy between missions, and especially the Japanese Kaguya spacecraft?

TC: The topography from their laser altimeter has been invaluable. First, it lets us calculate the slope of the ground. You don’t want to hit a slope [because you would then lose the benefit of a high impact angle -- DM]. Kaguya also gave us amazing information on the depth of the craters. Some of the errors in the previous estimates were significant, on the order of 500 meters to a kilometer. From the Kaguya terrain camera we got information on the surface roughness and albedo [reflectivity] of the craters. So, overall, they matured our current data set.

Also, with new LRO data coming online, we’ll be refining our numbers continuously to make the wisest choice of target. We will finally make an impact site selection by 30 days before impact, roughly the first week of September.

DM: How can ordinary people contribute to the LCROSS mission?

TC: Amateurs have already contributed, and with an impact with the moon high and the skies dark as far east as Texas, I hope many more will continue to contribute.

One thing to realize is that professional astronomers typically don’t point their telescopes at the moon. To most of them, the moon is a source of light pollution. So when we asked the best in the world to look at the moon for a change, there was a steep learning curve. One thing they needed to learn was how to find the crater you want to point to amongst a hundred or so other craters that look very similar. The shadows and bright areas change dramatically with small changes in the sun angle, so finding one’s way around the moon can be difficult if one has never looked before. To help, we asked the amateur community to image the moon at all phases and tilts so that we had a library of sorts for the various light conditions.

During the impact, amateurs with a minimum of about a 10-12 inch telescope can observe the impact. We will be soliciting these observations and will share them with others. [There is a Google Group for amateur observers at this link -- DM.]

DM: Finally, do your kids know that “Dad is a rocket scientist”? If so, are they proud of it, and are they paying any attention to the LCROSS mission?

TC: I have a son who is two and a half and a daughter who is five years old. They came to the launch, and when they look at the moon now they say, “Daddy’s rocket is flying to the moon!” After the launch my wife and children took a different flight home than I did. During the layover, on one of the cable news channels playing at the gate, they showed a replay of the launch. My children both yelled, “Daddy’s rocket!” My wife says that the people around them looked with a bit of a skeptical stare until she said, “Actually, it is their daddy’s rocket.”

Tags: Ames Research Center, Apollo, chunky, craters, interviews, Kaguya, LCROSS, LRO, Northrop Grumman, smooth, telescopes, Tony Colaprete
Posted in Missions, Science | 3 Comments »

LRO’s “BFF”

Monday, August 3rd, 2009

The second of the two moon missions that NASA launched in June is called LCROSS, an acronym for Lunar Crater Observation and Sensing Satellite. According to Tony Colaprete, the chief scientist for the LCROSS mission, “The younger folks at Goddard Space Flight Center have started calling it LRO’s BFF… at least until October 9.”

Hmmm… I can see some puzzled looks out there. Okay, I’ll explain. LRO is the Lunar Reconnaissance Orbiter (LRO), which launched on the same rocket as LCROSS on June 18. BFF is Internet-speak for “best friends forever.” (But you knew that already, right?) And October 9 is D-day for the LCROSS mission.  Unlike LRO, which will accumulate its results slowly and steadily over a period of one to three years, LCROSS will go out in a blaze of glory, and will do all of its most interesting science over the course of 5 minutes.

LCROSS consists of two main pieces — a spent rocket booster and a “shepherding satellite.” On October 9, around 4:30 AM Pacific time, the bigger rocket booster will slam into a crater near the moon’s south pole. Imagine an SUV crashing head-on into the ground at more than 5000 miles per hour! That’s what the impact is going to be like. It will be equivalent to the explosion of about a ton of dynamite. 

The explosion will be big enough, in fact, to be seen from Earth. That is the whole idea — to time the impact so that it can be tracked by all of the big telescopes on Hawaii, as well as the Hubble Space Telescope. Colaprete says that even a 10-inch telescope (well within the range of many amateur astronomers) should be able to see the flash, if it is pointed in the right place at the right time. If you don’t have access to a 10-inch telescope, you can also watch the impact over the Internet.

A minute or so after the big kablooie, the shepherding satellite will come swooping in, flying right through the debris plume. While it’s getting buffeted about, it will hopefully be able to sniff out any volatile compounds that have been excavated by the blast, including water vapor — the number one target of the mission.

We’ve seen tantalizing hints of water ice from orbit, but nothing that absolutely confirms it. We know that there is hydrogen in the permanently shadowed craters near the south pole, but there is no guarantee that the hydrogen is bound up with oxygen to make a water molecule. There’s only one way to find out for sure, and that is to “reach out and touch it,”  as Colaprete says. Or perhaps “reach out and blow it up” would be a slightly more accurate wording.

After it flies through the plume, the shepherding satellite will itself crash into the moon a few minutes later, creating a second and smaller blast. Colaprete is deliberately not building up any great expectations for this one, because it will be harder to control where the shepherding satellite lands. However, it will give scientists a second chance to look for signs of water, or at least to understand the mechanical properties of the ground that LCROSS is crashing into.

Last month I had a chance to interview Colaprete by e-mail and then in person at the Moon Fest. I also went to his talk at the Lunar Science Forum. In my next post I will try to reproduce these three “conversations” as if they were all one interview.

By the way, the LCROSS mission reminds me of something interesting I learned when researching my moon book. After Russia launched Sputnik in 1957 and when our scientists and politicians were debating what we could do to respond, one of the crazy ideas that was floated was to nuke the moon. That’s right, launch a nuclear missile at the moon and blow it up, thereby proving somehow that we were bigger and badder than the Russkies.

What a stupendously bad idea this would have been, because we would have learned nothing from it. The response we chose instead — sending men to the moon — was vastly more difficult, but we got so much more out of it, including a real understanding of the moon’s origin and makeup, plus the fleeting goodwill of all of the rest of the world.

It’s just a tiny bit ironic, then, that on our second round of missions to the moon, one of the first things that we are doing is slamming a rocket as hard as we can into the moon to create a big explosion. I mention this parallel with some hesitation, because I don’t want to make LCROSS seem like just a stunt. That is exactly what it is NOT. There are two huge differences between this mission and the stunt that was proposed back in the late ’50s:

1. A spent rocket booster is not a nuke.
2. The LCROSS mission was designed with a specific scientific purpose in mind: to excavate water ice, to see first of all if there is any ice there and secondly how much there is and how easy it is to get it out. These are vital things to know if we are ever going to set up a permanent moon base.

Maybe these points are obvious and didn’t even need saying, but I just wanted to explain why the LCROSS mission is not just about some engineers blowing things up for fun.

(Still, blowing things up is fun … See any episode of Mythbusters for proof!)

Tags: blaze of glory, hydrogen, ice, kablooie, LCROSS, Mythbusters, nuke, Tony Colaprete, water
Posted in Science | 2 Comments »

A colder and wetter moon?

Wednesday, July 22nd, 2009

Yesterday I went to the Lunar Science Forum at Ames Research Center, which was the scientists’ version of a Moon Fest – a chance for all the recent and current moon missions to unveil their latest and greatest findings. According to the organizers, more than 500 people registered, including 200 just since last Friday. I don’t think that all these people actually came — the main meeting room holds 300, and it was not filled to capacity. Nevertheless, it was a well-attended (and well-Twittered) event.

Yesterday the science teams of the LRO and LCROSS missions, which just launched last month, presented their data publicly for the first time. As David Morrison, the head of the Lunar Science Institute, said in his introductory remarks, “Last year most of the papers reported plans, but I’m delighted to say that most of the talks this year are about results.”

All of the LRO results are very preliminary, because LRO is still in its “commissioning orbit,” when they are still warming up and checking out the systems. By the way, I mean warming up quite literally. Most of the instruments have residual moisture in them from their time on Earth. (So do most tourists, after a few hours in the humidity of south Florida!) So they have to go through a “bake-out” period to dry out all of that extra moisture. The LRO camera finished its bake-out on July 10, but even before then (as mentioned in this entry) it started sending back fabulous pictures.

Also, scientists from two other moon missions spoke yesterday. There was one presentation on the Japanese Kaguya mission that just ended a week before LRO lifted off, and three about the Indian Chandrayaan-1 mission that is still ongoing.

The most interesting news yesterday all had to do with results that we can’t really talk about yet! One of them is so preliminary that no one can really interpret it yet. The other two are results that are going to be published soon but are currently under “embargo,” meaning that the scientists aren’t supposed to talk about them until the publications come out.

First, David Paige, principal investigator for LRO’s Diviner experiment, showed some of Diviner’s first measures of the temperatures in the moon’s permanently shadowed craters. Remember that these are supposed to be “cold traps,” where water molecules could perhaps accumulate as ice because they are too cold to float away. The first temperature readings in Amundsen crater turned out to be even lower than expected: around 33 degrees Kelvin (or 33 degrees above absolute zero).

No one had predicted such a low temperature; I think that 70 degrees Kelvin was closer to what they had expected. As Paige said, “If this is true, it’s colder than the poles of Pluto!”

From his wording, you might correctly infer that Paige is not really sure this measurement is right. The instrument has been calibrated, but he said there are some possible reasons why the instrument-measured temperature may not be the same as the physical temperature. (For example, they don’t really know what kind of surface they are looking at — rocky or soft and fluffy — and that can make a difference to how they estimate the temperature.) The instrument is still too fresh and new, and the finding too unexpected, to put a lot of stock in it yet. But what it could mean is that the permanently shadowed craters are a better cold trap than we thought.

Two other surprising results that can’t be talked about yet came out of the Chandrayaan-1 mission. Carle Pieters of Brown University reported on the Moon Mineralogy Mapper, and said that her team had made a new discovery on lunar volatiles that she can’t discuss yet. Of course, the most important potential  ”lunar volatile” is water. But, she said, “Don’t give me wine and try to dig the secret out of me.”

Then Paul Spudis, whose Once and Future Moon blog is always thought-provoking, talked about the results from his mini-SAR (synthetic aperture radar) experiment, which is also on the Indian Chandrayaan-1 spacecraft. Like Pieters, he has a result that he can’t talk about yet, but he said, “I may be susceptible to being plied with drinks!”

Mini-SAR is also looking for water ice; the idea is that ice will reflect a circularly polarized radar beam differently from rocks. (The radar wave will actually go into the ice before bouncing back, because ice is transparent.) This is similar to the way that ice was first detected at the south pole, by the Clementine mission in 1994; Spudis was the deputy leader of the Clementine science team. However, the Clementine satellite only got one brief peek at the south pole, and so its results were very ambiguous. You can’t do very much in science with one data point. Chandrayaan-1 should do much better. We will have to wait to find out just how much better it’s done.

Nevertheless, I will transcribe a fascinating exchange that occurred during the audience-questions period after Spudis’ talk. Clive Neal, the chair of NASA’s Lunar Exploration Analysis Group (which advises NASA on the choice of moon missions) went to the microphone.

NEAL: You said there were some things that you cannot talk about, but then you proceeded to talk about some of them… (Laughter from audience.)

SPUDIS: You don’t know that! (Laughter.) You’re making an assumption, and maybe it’s warranted, maybe it isn’t.

NEAL: So I’ll ask my question as delicately as I can. You showed data that seemed to be consistent with the presence of water ice on the moon. Would you care to comment on that? (Loud laughter.)

SPUDIS. No! (Laughter.) But you’re welcome to draw whatever conclusions you care to.

NEAL: Can I just rephrase the question? If I buy you a beer, would you comment?

SPUDIS: It depends on what kind of beer and how much. (Laughter.)

DAVID MORRISON: I think all of us are beginning to assume that in a month or two we’ll have a wetter moon than we do now.

SPUDIS: Well, the moon isn’t going to change. (Laughter and applause.) Our perceptions might change. But, you know, some of us have had this perception for a long time.

Make of it what you will! Just don’t blame me for breaking any embargoes.

Other tidbits and factoids from the first day of the meeting:

These roads are so confusing.

• Google released its new version of Google Moon on Monday, and there was a large screen in the tent demonstrating it. It’s a huge improvement over the previous map-based Google Moon. This one has all the latest imagery from the LRO mission, and will continue to be updated constantly — so look for it to continue improving by leaps and bounds over the next year.
• The LRO launch was perfect, and that is very good news for the scientists, because it means that there is more fuel left for an extended mission than they could previously count on. Craig Tooley said that this could extend the life of the mission by a year. (The spacecraft has a planned one-year life span, followed by a two-year extended science mission. I interpret Tooley’s remarks to mean that it could continue orbiting for a fourth year.) I would think that the extra time would be especially valuable for the narrow-angle camera, which can only image about 10 percent of the moon in any given year.
• I asked Sam Lawrence, of the LRO camera team, whether they had felt under any pressure to get the pictures of the Apollo landing sites out early. He said, “I won’t lie to you. Several people in Headquarters simultaneously and independently came up with the idea of taking pictures of the Apollo landing sites. But Isaac Newton is in the driver’s seat. It was largely serendipity that we happened to be in the right place to image them.” In fact, the Apollo 12 landing site has not been imaged yet, but it should come around into the camera’s view in a couple of weeks.
• There was lots of Twittering going on at this conference. I sat behind someone whose laptop had a screen full of twitters. I have so far refused to get on twitter.com, but those of you who are might want to check out what the scientists are twittering about.
• Yes, there is such a thing as a free lunch! Registration for this conference was free (which is already unusual for a scientific meeting) and the Lunar Science Institute provided the lunch and refreshments free of charge, too! Shhh… Don’t tell Washington that they’re using your tax money to feed starving scientists …

Tags: Ames Research Center, beer, Chandrayaan, cold trap, free lunch, Google, ice, Kaguya, LCROSS, LRO, Lunar Science Forum, Lunar Science Institute, Twitter, water
Posted in Just for Fun, Missions, Science | 1 Comment »

Moon Fest 2009

Monday, July 20th, 2009

Yesterday I went to the Moon Fest at Ames Research Center, one of the events that NASA has organized in honor of the anniversary of the first moon landing. In every way except one, the afternoon left me very optimistic about the future of space travel.

First, one thing that impressed me was that there was a big crowd. This wasn’t “book reading at the bookstore” big or even “Friday night at the movie theater” big. It was “sports event” big, with a traffic jam waiting to get off the highway, traffic cops showing people where to park, etc. I would guess that at least a couple thousand people came. That’s pretty exciting — a couple thousand people for a science event!

Crowds at Moon Fest; Lunar Science Institute in semi-background; Hangar One in background

Of course, there were lots and lots of kids, and somewhat to my surprise there was a very well-planned choice of activities for them. They could drive robotic “moon buggies” or look through a telescope at the sun or build and launch model rockets out of paper and plastic. If your rocket landed in a “moon crater” (a big bowl-shaped piece of plastic) you would win a prize. I don’t know if the kids realized it, but this game was intended to tie in with the LCROSS mission that is currently in orbit about the moon, and will smash into a lunar crater on October 9. Here are a couple of kids getting ready to launch their rockets:

Countdown begins

The Gyroscope Effect

And here’s another girl learning about angular momentum. She is standing on a rotating platform. When she tilted the spinning bicycle wheel, the conservation of angular momentum caused her to start spinning around.

For adults or more seriously minded folks, there was also a big tent set up for lectures. I got there in time for a lecture by Tony Colaprete, the principal investigator for the LCROSS mission. I did a short interview with him afterwards, which I will write about in a future post. Again, the size of the crowd was very respectable, probably at least 300 people.

The best speaker, though, was Donald Pettit, an astronaut who has flown aboard both the Space Shuttle and the International Space Station. In fact, he was one of the astronauts who was on board the ISS when the space shuttle Columbia exploded on re-entry in 2003, and he was stranded there until he could get back home on a Russian Soyuz spacecraft. (He spent five and a half months in orbit.)

Kids love astronauts!

Astronauts are the closest thing that NASA has to rock stars. The questions after all the other talks were asked by adults, but after Donald Pettit’s talk the kids couldn’t wait to ask questions. They wanted to know how germs work in outer space, how long it takes you to get over your “sea legs” (or “space legs”) after you get back home, and how old you have to be to be an astronaut.

Pettit’s answer to that last question surprised me. He said there is no age limit, minimum or maximum. BUT most of the space shuttle and space station astronauts these days are scientists, which means they have to get a science degree and they have to make some kind of impression with their research. So the typical astronaut these days is in his or her late 30′s or early 40′s. That was older than I would have expected. By the way, I hope the kids caught the subtext of Pettit’s answer: You want to be an astronaut? Study science.

Pettit’s talk had lots of great video clips. He showed a simple gadget he invented for drinking tea in outer space, and he showed himself “eating” blobs of tea with chopsticks. He showed a film of sunrise as seen from the space station: from full darkness to full sunrise in seven and a half seconds! He showed how they recycle urine (“yesterday’s coffee”) so that you can drink it again (“today’s coffee”). His talk was light-hearted (“In space, you get to play with your food and call it science,” he said) but at the same time he did not miss any opportunities to point out that the knowledge we are gaining will be important to us as we continue to voyage in space. For example, recycling every little bit of water that we can will be vital in the nearly anhydrous environment of the moon or Mars.

Over and over, Pettit emphasized that “strange things happen at frontiers.” And that’s why we want to go to frontiers, because that is where we can discover new things and see the world in new ways.

So, as I said, I came back from the Moon Fest feeling good about space science.  The public interest is real, if you can engage it. I felt as if NASA is doing wonderfully with its educational mission. In the 1960s they could never have pulled off an event like this. Also, NASA still has a corps of talented and charismatic astronauts, like Donald Pettit, who can make a passionate case for why space is important. And there is still a whole universe out there of things to be discovered.

There’s only one thing missing from this picture. You’ve got the enthusiasm, you’ve got the talent, you’ve got the unexplored frontier – but you need to have a mission. You need something for all these people to get excited about. You need a challenge that is worthy of the talents of the astronauts and the scientists and the huge support staff behind them.

The Shuttle is good … but it’s retiring soon. A couple years from now, for the first time since the 1970s, the United States won’t have any spacecraft capable of taking humans into space. The next time Donald Pettit goes into orbit, he will have to hitch a ride with the Russians. The Space Station is great … but just a little bit too ordinary. I don’t think that it inspires very many people. There’s only one mission that NASA ever had that was transcendent, and that was going to the moon.

So that’s the missing piece. All of NASA’s literature still talks about returning to the moon by 2020, but I am far from convinced that it will happen. It will take leadership to stay the course, and I still haven’t seen the proof that our current leadership is committed enough to it. But we’ll see! Hopefully, when the 50th anniversary of Neil Armstrong’s “one small step” rolls around, we will either have people on the moon or we will have plans to get them there in the very near future.

Tags: Ames Research Center, anniversary, astronauts, frontiers, LCROSS, NASA, Neil Armstrong, optimism, recycling, shuttle, space station
Posted in Just for Fun, Media, Science | 2 Comments »