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The Planetary Society BlogBy Emily LakdawallaISDC: Outer planets and Mars talksMay. 10, 2006 | 16:48 PDT | 23:48 UTC
The International Space Development Conference is not the kind of meeting I usually attend. Typically, I go to meetings of scientists with the intent of learning about what's going on and interpreting their results for those of you who aren't so privileged as to get sent to these things. ISDC is different; it is a conference specifically intended for the broader public, what we at the Society like to call the "interested public." That is, the meeting assumes you are already into space exploration and just seeks to get you more informed or more excited about it. As such, I was actually less interested in the speakers themselves than I was in seeing how the people in the audience reacted to the speakers.
Slava Turyshev gave a good talk on the status of the research into the Pioneer Anomaly. He had an interesting way of presenting the problem: "Pioneer spacecraft performed largest-scale Newton's law test in the solar system; and it failed. If we will learn about this effect and identify it with onboard forces, we will confirm Newton's law at great distances." I hadn't really thought about it that way before. It's often mentioned how detailed observations of perturbations in Mercury's orbit confirmed Einstein's general theory of relativity. In the same way, detailed observations of the Pioneer spacecraft were essentially a test of Newton's laws of motion. (Slava explained that at such great distances from the Sun, it really is Newton that applies; relativistic effects are completely negligible at the scale of the measurement sensitivities that they can achieve.) And, the test failed. So now they're trying to figure out why; it's either because they didn't understand something that was affecting their experiment, or because there's something wrong with Newton's laws at great distances from the Sun. Either way, Slava said, if they can figure out what's going on, everybody wins. Dave Doody gave an excellent overview talk on Cassini-Huygens, including a dramatic retelling of the scary morning last week when Cassini was not talking to Earth. (More on that later.) He also showed the unbelievable new video that they have put together of the Huygens descent. I'd not had time to watch it yet, and I am stunned by how much data they have crammed into the screen. The video contains information on just about every bit of engineering data you could want -- rotation speed and direction, the angle of the spacecraft, its height and position above ground, the view from its cameras, when and where pictures were being taken, the strength of the signal to Cassini, and on and on, in an information-packed visual and sonic display. (Edward Tufte would be proud.) Rosaly Lopes gave a talk on the New Horizons mission to Pluto and beyond. The item from her talk that got a murmur from the audience was her mention of the fact that nitrogen ice crystals covering the surface of Pluto might be several centimeters long -- "a fantasy world," she said. That made me muse about how different Pluto, the landscape would be from Pluto as seen from space. Just think how different an impression we have of Terra Meridiani now that Opportunity has landed there. Now try to form an impression of a world with an appearance much, much less familiar than Mars'. Just think about it. Distant, cold, dim, frosty Pluto, its icy scarps and muted slopes rimed with four-centimeter crystals of glinting solid nitrogen. Whoa. Rosaly also pointed out that "What we know of Pluto now is not unlike what we knew of Titan before Cassini." All we have of Pluto is some blobby-looking maps that are the result of painstaking days and years of ground-based observations; the maps do little more than tell us that the surface would probably be really interesting if only we could see it. That's what Titan looked like to us before Cassini got there. Of course, New Horizons will have little in the way of any pesky atmosphere to deal with at Pluto; its images should be sharper than Cassini's are of Titan. That was all Saturday. Sunday morning began with Dan McCleese giving a presentation on basically everything that's going on on Mars now and in the future (at least from JPL's point of view, which isn't complete but which covers quite a lot of Mars activity). One of the parts of his talk that I (and the audience) liked best was when he began talking about the future of Mars exploration, particularly the Scout program. "Imagine this," he said. "You write a proposal. If you win, you get 475 million dollars to build and fly your own mission to Mars." Of course, he said, you have a couple thousand people looking over your shoulder and helping you out to make sure you get it right, but that's basically what these competitively-selected, PI-led missions come down to. Imagine winning that lottery! Another of Dan's comments that the room enjoyed had to do with future missions trying to figure out where the methane on Mars was coming from. "What makes methane? There are two dominant ideas. One is an active geologic process that pumps water and methane into the atmosphere. The question is, is this warm wet region a habitat? Could we look there for life? "The other thing that makes methane is cows." The audience chuckled here; I hoped he was going somewhere with the cows comment, and actually, he was. "Now, we really doubt that it's cows. We have one guy who has a Scout proposal that could detect two cows on Mars by the methane they produced. If there are organisms on Mars making methane, we could detect it from orbit." Although the "cows" and "pigs" jokes that people like to make about methane are a little silly sometimes, the idea that somebody has come up with an instrument that could detect methane at a level equivalent to the emissions of two cows is pretty cool. Dan also talked about what's coming in the more distant future. We have Phoenix in 2007, and Mars Science Laboratory in 2009. What's after that? There should be a Scout launch in 2011 (everybody hopes), and an orbiter called Mars Science Orbiter in 2013. In 2016, it's back to rovers. We could see either the Astrobiology Field Laboratory, which would be a duplicate of Mars Science Laboratory but with a different instrument package designed to explore a site for its biological potential, or a couple of "Mid Rovers," MER-sized beasts exploring new locations. Dan explained that "We would fly AFL only if MSL finds organic molecules. If we do not find organics, we want to send smaller rovers, somewhat like MER missions, to other locations to search further for organics." Finally, he closed with a rather sad observation on the more distant future of Mars exploration: "Very long term is to accomplish a mission we have wanted to do for decades -- since late in the 1960s. Sample return in the future remains a very high priority. But sample return is a tough, tough problem. You can think of it as five missions in a string to bring back about a pound of rock and soil." This got a definite rumble from the audience. Dan took pleasure in describing what it would take to get this sample back, down to the helicopters and machine-gun-equipped soldiers accompanying "the most expensive rock on Earth" from its sample return site to its laboratory. "This is a problem. It costs a great deal of money to do this. For 40 years we have seen it move off into the future. We have been as close as 8 years from it; we are now maybe 20 years from it. We do not know how long we will have to wait." Hopefully the other ISDC attendees got as much pleasure out of these talks as I did. It's clear that these people, at least, really enjoy telling audiences about the adventures they have on their space missions, exploring our solar system -- exploring, I feel compelled to editorialize, much more than astronauts can! To be sure, there's something vicariously exciting about imagining being an actual human in space. But I think most space scientists have just as thrilling a vicarious existence through the robots that are their eyes and ears, and that thrill comes out when they talk to people about what they've been working on.
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