MainlyMartian

A nice resource

Bruce points out to me that ESA now archives accessible pdfs of scientific papers that have flowed from ESA projects -- such as the recent Mars papers in Nature and Science. So if you are lacking a subscription this is the place to go: a new and different sort of openness that we can all get behind...

In his Nature commentary on the Murray et al "Elysium Sea" paper, discussed here, Vic Baker of the University of Arizona coins a nice new phrase for the idea that there was a warm and wet early Mars that then dried out into the Mars the Vikings saw: he calls it MIDDEN, for Mars Is Dead and Dry Except in the Noachian. Baker is also more generous towards the sea idea than one might have expected from someone whose office is not that far away from Alfred McEwen's, since McEwen, who has studied this part of Elysium more than anyone else, is absolutely adamant that the flowing stuff was actually lava.

When everyone is back from LPSC next week I'll try and find out how this lava v water debate is shaping up. It's a measure of the interesting times we live in that volcanic activity in the past few million years, once widely considered more or less unthinkable, is now seen as the conservative option.

Bruce on the future; Dwayne on the past

Bruce Moomaw beat me to the punch in the comments -- I was already planning to recommend his lengthy and impressive account of the questions raised by the effort to make a roadmap for Mars explorations, which I was digesting over the weekend. Full version here: Bruce's précis, lovingly hand crafted to meet the needs of this blog's readers, is in the comments here. The only thing I'll add to the discussion for the time being is that I'm now sure the MSL delay to 2011 is real, but that as yet I'm not quite sure that the doubling up will happen, in that it might be announced but the second one might slip even further.

Meanwhile, over at Jeff Foust's Space Review the excellent Dwayne Day has written up the damning ESA report on Beagle (pdf here). The full version was released, thanks to New Scientist's moves under the new UK Freedom of Information Act, when I was in logic-board hell. I kept meaning to write about it after the fact, but now I don't think I'll bother, as Dwayne seems to me to have the matter pretty much bang to rights. Dwayne's insights are particularly worthy of our attention since he worked on the CAIB report after the loss of Columbia, and thus knows about this stuff. A second part of his thoughts on the subject are promised, but as yet has not appeared...[Update March 29th: the second part's now posted here]

And while we're at it, Jeff's account of what Mike Griffin, NASA's new administrator, feels about the space exploration initiative (oh, sorry, the new vision), the shuttle, and so on is also well worth a read.

So this post should in fact be called "Bruce on the future; Dwayne on the past; Jeff on the man of the moment". But that's too long.

Utterly beautiful maps

I should have done this a very long time ago.

The other day, at a party, I saw a bookclub version of Mapping Mars (a friend's party, I should add -- it's not the sort of thing you find in a stranger's house...) The bookclub version has no endpapers at all, not even the somewhat unsatisfactory ones found in the UK paperback. However, here on the web you can get the most splendid possible endpapers, thanks to the excellent Ralph Aeschliman. Ralph did the black and white endpapers for the hardback, but has also developed these more detailed maps in colour, which situate all the features mentioned in the book and quite a few more besides.

These are the maps that I'd like the reader to have to hand when reading the book. Book; maps; maybe a glass of Gigondas or a dram of the Black Bottle; a fire just past its roaring peak, somewhere between flame and ember; a propensity for dreaming: that's the way to do it.

The downloads about half a meg. Here's the western hemisphere (front endpaper)

Here's the eastern.

Or, if you prefer, here's the whole thing as a Lambert projection

If you like them, let Ralph know.

MSL shakeup -- and a possible methane mission?

The rumours about MSL, mentioned a while back, seem to be getting stronger and stronger. Since the most recent MEPAG meeting a number of people have started more or less assuming that MSL is going to slip back at least one launch opportunity, to 2011; there's also talk of it being doubled up into an MSL A and an MSL B, like MER. It's not been announced yet and may not be a done deal, but the delay, at least, seems very much to be the way that the wind's blowing. It's possible that a formal decision is going to wait until NASA's new administrator, Mike Griffin, weighs in.

An ancillary rumour suggests that if this happens there will be serious consideration given to moving the next Scout opportunity for a small mission up from the 2011 launch opportunity to the 2009 opportunity. Four years is a very short time in which to go from a sheet of paper to a spacecraft, and a truncated selection process might be put in place, in which only the scouts that were shortlisted last time need apply. Those three were: Scim, a mission to pull dust from the upper atmosphere; Ares, an aircraft that would do magnetometry, inter alia; and Marvel, an orbiter with which to measure atmospheric trace gases, including methane, based on the bus for Mars Odyssey. If it were done that way, then the case for Marvel would be extremely strong: the science basis is all the stronger now we have reports of methane, and the technical risk has to be low compared to the other two, since it's a fairly straightforward orbiter, content to look at the atmosphere from above rather than rip through its edges with ramscoops flaring, or extend its wings and try and fly through the stuff. If you wanted to be really practical about the matter, you could save time by just selecting Marvel straight out of the gate -- but I'm not sure that that's actually legal for a scout mission.

Marvel would get really accurate data on methane levels, it would measure any seasonal variations, and it would pick up a bunch of other trace gases if they're there. It would also have a good chance of measuring the carbon-12/carbon-13 ratio in the methane, a measurement which, if it is different from the isotope ratio in the carbon dioxide, would offer strong evidence for a biological source. (The idea is that the methane-making organisms would feed on a well-mixed global reservoir of carbon dioxide, but would discriminate between isotopes as they did so, just as methane makers and photosynthesisers do on the earth; most non-biological processes don’t make such discriminations.) But in an ideal world -- say, for the sake of argument, a world in which the aim was not to fly an already accredited Scout design, but to fly the best methane mission you could -- you'd want to at least consider an alternative mission that looks for the same data a different way.

Marvel would be in an orbit that kept it close to the terminator; its spectrometer, instead of looking straight down, as most spacecraft instruments do, would look at the horizon -- the planet's limb -- in order to see the sun through the atmosphere. This means it gets a strong signal, because it's got a very bright light source shining through a lot of gas. An alternative, which Mike Mumma at Goddard has thought about, is to put a telescope in a halo orbit around the Martian L1 point, which is on a line between Mars and the sun. At L1 a telescope could spend all its time looking at the whole sunlit face of Mars -- and paying attention to any region that was of particular interest.

The challenge of an L1 mission is that the signal is a lot weaker. Your light source is the surface of Mars, which is a lot less bright than the sun. And the light passes through much less of the atmosphere. Light coming to Marvel on a tangent to the planet's surface goes through something like 40 times as much of the atmosphere as light reflected from the surface to the L1 point, and thus the spectral features due to methane, or anything else, will be considerably stronger.

The advantage of L1 is that you could look at specific places -- at resolutions down to a few tens of kilometres -- and look at them at any time of day that you chose. Marvel has to look only at sunsets or dawns, and it can't choose to focus down on a particular region (though it will see all the regions of the planet on a fairly regular basis). If methane levels are strongly variable in space and time, that would seem to be an advantage for the L1 mission. The lower signal at L1 should be something that can be compensated for in principle simply by taking data for longer; in principle, an L1 mission could stare at a particular spot all day.

I really don't know which mission might be better. If I knew for sure that Marvel's signal to noise ratio made it significantly more capable in terms of isotope analysis, I think I'd go with that. There again, the idea of being able to look down wherever and whenever you want is certainly appealing, especially if it were to turn out that there are point sources and complex surface chemistry. But developing a mission from scratch to fly in 2009 would be very, very hard, and I think that the greater amount of design work already done on Marvel would probably trump all other factors. So if there is to be a methane mission at all, it may well be a case of love the one you're with - not too hard, since Marvel is pretty damn loveable.

Bill Hines, RIP

Bill, a leading light of the first generation of space reporters, died of pneumonia last week at the age of 88. There's a good obit in the Washington Post. I met him at the Voyager 2 Neptune flyby, where I guess he was one of the oldest journos and I one of the youngest. We met because, at The Economist, his wife Judy was a stringer for us and became a good friend. Over the days of the encounter he showed me the ropes, introduced me around and so forth.

Bill was one of the people who made the lives those of us who now write about this stuff possible, by understanding that, after Sputnik, space and science in general needed to be covered and going out and covering it. He built the appetite that we now feed -- while at the same time teachiong us not to treat the whole enterprise just as an occasion for awe, but as a story to be covered as incisively as possible. For example, he played an important role in getting the lapses that led to the Apollo 1 fire properly reported and investigated. While space was far from the only thing he covered -- he was the Chicago Sun-Times's DC bureau chief and earned a place on Nixon's enemies list (to his delight), as well as breaking the details of David Stockman’s budget cuts in the early 1980s –- it was space that he really loved, and he spent a lot of time on it. When I was looking at old news photos for Mapping Mars it always gave me a kick to see Bill in JPL covering the Mariners or the Vikings, questioning Sagan or Bruce Murray or Larry Soderblom. I’d think about him when Isaac Jaffe, the Robert Guillaume character in Aaron Sorkin’s Sports Night, used to reminisce about the Mercury program or read Tim Ferris to his bemused subordinates.

Meeting Bill out in Pasadena was a wonderful link to a (slightly) earlier age. Later, staying with him and Judy at Mouse Trap Farm, watching the humming birds at their feeder, was just wonderful.