MainlyMartian

Dead Dog

So, at a press conference in London this afternoon, Colin Pillinger declares Beagle 2 all but officially dead. The latest round of attempted communications turned up nothing, and there is no plausible scenario in which the spacecraft has not yet transmitted anything at a time when we've been listening but is still capable of transmitting something. There is a last chance involving a reboot procedure, but it's clear that almost no hope at all is held out for it. On February sixth, it appears, the decision to draw a line under the mission. But as Pillinger says, everyone involved is now "looking to the future" -- specifically, the possibility of reflying the Beagle payload in some way or other in 2007.

There will be an inquiry, or a review, under the auspices of ESA. No-one yet knows who will chair it or serve on it. Its biggest problem will be that Beagle was out of contact from the moment when it left Mars Express, and so ascertaining when whatever went wrong went wrong is going to be hard. (The flight team is currently reanalysing all the data from before the separation to make sure that Beagle 2 was absolutely OK up until then). It's worth noting that Spirit and Opportunity both sent back telemetry all through their descent - and, as I understand it, the decision to arrange matters so that they could stay in constant touch actually increased the risk of failure, because it constrained their descent times to the mid afternoon, which is when the wind risks were highest. The need to know what had gone wrong if there was an accident trumped the need to minimise the risk of an accident.

If you're running a program that needs to learn from its mistakes, that's a good position to take (and one mandated by NASA, I think, after the telemetry-free loss of Mars Polar Lander). Colin insists that there was no way at all that the mass for a telemetry system that worked during entry, descent and landing could have been freed up. Unfortunately, that now makes it harder to turn the one-off Beagle 2 mission into an  ongoing program - which is what the Pill is angling for. If no one can ever say for sure why Beagle 2 failed, the case for trying again is clearly weakened. Every time the team would say "we've thought of everything" the sceptical reply would be "you said that last time".

While we're at it, it might be quite a good idea at this point to provide an open accounting of who paid what for the project, a subject on which I for one am still rather hazy (for example, there was once talk of 10 million pounds in sponsorship: how much of this materialised, and did the British Government made up the difference?) 

I have a certain ambivalence to all this. I would have loved it if Beagle had got safely to the surface and made its measurements.  For a long time I had doubts that it was going to be able to, because it just seemed a priori unlikely that a team with no experience of running planetary missions would be able successfully to mount an ambitious one at a headlong rush on a tiny budget. They weren't deeply informed reservations - just doubts. They might have been erased - or confirmed - if I had done some reporting on the project, but Colin, while always being perfectly pleasant to me when we met, made it clear I was a journalist he didn't want too close. He declined to speak to me when I was assigned to write about Beagle 2 first by Science and then by the Telegraph magazine. That's his right, though it pissed me off at the time.

So with no professional reason to spend a lot of time thinking about Beagle 2 I came to the opinion that, since it was going to go ahead anyway, I should just sit back and hope for the best. Writing anti-Beagle stories - "Why is the government spending so much on something which has only a 50-50 chance of success?" etc - seemed unproductive and even a little unsporting. And the possibility of success was beguiling. Now that possibility is no more, it seems that at least some of those questions really should be asked before we start talking about reflying the mission in 2007, as Colin was today. For example, it would be nice to know more about the reasons why a Beagle follow on didnt even make the shortlist when it was proposed for the 2007 Mars Scout opportunity.

If you want really vituperative anti-Beaglism, though, I'm not your guy -- Jeffrey Bell is. Bell's the only person I know of who has actually argued in public that Beagle 2's demise is a good thing. Bell, an astronomer based in Hawaii, is outspoken in a way that can be quite brave -- I remember him standing up to Dan Goldin rather magnificently at a space science meeting in the early 1990s. There's some merit in some of the points in his argument that the Beagle's demise is something to be welcomed; other parts seem poorly founded, and one aside is foolishly malicious in a way that only ignorance of what the accusation actually means in context could come close to excusing.

Opportunity rocks

I heard Steve Squyres on the radio as I was walking through the park this morning, and he sounded just tongue-tied at the sight of Opportunity's landing site. Many people had predicted that Merdiani Planum (which I keep wanting to refer to by its old name of Terra Meridiani) would look strange compared to the martian landscapes we've seen before, and it certainly does. Most importantly, it seems to boast genuine outcrops - rocks sticking out of the surface, rather than rocks scattered over the surface. Most of the rocks we've seen on Mars up until now have been wandering rocks, rocks that ended up where they ended up because they'd been washed there by floods or they'd been thrown there by impacts. Here, in Meridiani Planum, there appears to be bedrock exposed at the surface. There's the chance to look not at the history of Mars in general, nor of unseen bits of Mars upstream - but of the bit of Mars we're actually experiencing. Time to get the hammers and eye lenses out.

While we wait to see what the rocks are made of, it's worth pausing to wonder whether landing sites will ever again be able to surprise the people whose craft end up there in the way that Meridiani Planum seems to have flabbergasted Steve. The next landing site, the one Phoenix will set down on in May 2008, will have been stereoscopically imaged from space by the Mars Express camera, giving a beautiful three dimensional context for it. It will also have been scoped out, I imagine, by HiRise, the super-camera being developed for NASA's Mars Reconnaissance Orbiter (not least because Peter Smith at the University of Arizona is responsble for both projects). HiRise will send back images with a resolution of one metre or better that cover quite significant swathes of ground; its individual frames will be so data rich that they will quite literally be best seen on Imax screens. It will also be able to operate in a stereoscopic mode to produce three dimensional pictures.

With that much pre-landing imagery, I'd imagine that it will be fairly hard for a landscape to surprise us quite this way again. One more way in which our relationship with the planet next door is changing - the flipside, I suppose, of the ability to actually see ourselves in the sites once we're there (see previous post). Some thrilling surprises lost - an enriched sense of being-in-the-world gained.

Look at those cavemen go

An amazing new set of images taken by the MOC team at Malin Space Sciences reveal Spirit in situ - a human artefact of the surface of an alien planet. We strain our eyes through our most sensitive camera in an orbit 100 million miles from home - and we see ourselves, down on the sand, at the edge of visibility, a single pixel in the desert. The circuit is complete.

We see how we got there - a chain of dents in the surface where Spirit's airbags bounced along. We see the litter - the parachute, the heat shield - unavoidably strewn around the place in the haste of our descent. We see where we're going (if the flash memory can be properly disciplined). And we see how fantastically precise our knowledge of the distant situation is; the point in the picture where Spirit's controllers thought their spacecraft was, on the basis of the landmarks they saw surrounding it, is within ten metres of where the thing actually is, as seen from above. Ten metres!

For the first time, we're looking at an alien planet, and we're seeing not our hopes or our fears or any of our futures - but our present. Is there life on Mars? There is now.

Note added later: the Planetary Society's page on this is a much quicker download. And it also shows up a touch of hyperbole on my part: the lander's more than a pixel -- you can see the shape of the petals.

Great not-really-news

Is this evidence of life on Mars?
Mars: water, river valleys, but was there life?
Water of life found on Mars

Thus vast headlines in the Independent, the Guardian and the Times this morning, all of them devoting all of the front page above the fold to results from Europe's Mars Express. Late editions of yesterday's Evening Standard gave the whole front page to the story:

Eureka! We've found water on Mars

The other UK broadsheets also have big front page pix, though their headlines don't scream the news quite as large (the tabloids appear to have other fish to fry). It's all a) very exciting, b) beautifully illustrated and c) rather disingenuous.

To begin with, it's important to distinguish between liquid water and water ice. Liquid water is the really important stuff. Liquid water appears to be a necessary condition for life on the earth, and thus probably for earth-like life elsewhere. Since the key to Mars's attraction is its possible suitability as an abode for life, this makes water on Mars a big deal. There's lots of geomorphological evidence for liquid water in the past, both the relatively recent past (the gullies discovered in images from Mars Global Surveyor) and the incredibly ancient past (the larger valley and flood features, some now being beautifully re-imaged by the Mars Express camera). There are hints that there may be traces of liquid water around today - the best, I think, is the study by Oded Aharonson and his colleagues suggesting that liquid water in tiny traces may play a role in the "slope streaks" found in some places. (The paper on this is available as a pdf here) But no one has discovered liquid water on Mars, nor would anyone, I think, claim to have done so.

What the Mars Express people are talking about is water ice. To an earthly imagination - the imagination, for example, of a news editor - the distinction between water and water ice may seem a bit silly: ice is water, really, after all, isn't it. This point of view is not stupid, just understandably parochial. On the earth ice is a temporary condition water finds itself in before melting back into a liquid, and so to find ice is more or less the same as finding liquid water, as long as you're willing to wait a bit. But on a cold planet with a very thin atmosphere water doesn't work this way. Ice on Mars can be stable indefinitely - and when some external change makes it unstable, it may well turn straight into water vapour without ever passing through a liquid phase, a process called sublimation. To find water ice on Mars certainly raises the possibility of liquid water, but it doesn't entail it as a logical necessity.

The fact that it raises the possibility of liquid water, though, still makes the discovery of water ice a historical step forward in our understanding of Mars. But this is where the disingenuousness comes in. Take Charles Arthur's piece in the Independent. "Since [the Viking missions of the late 1970s] a succession of missions have failed even to confirm the presence of water there, a prerequisite for life. Until yesterday." It's interesting to note Charles's choice of the word "confirm". Because though he doesn't say it, the fact that there is water ice on Mars was convincingly demonstrated by the Vikings almost thirty years ago.

The man who did the most to take this historical step was Hugh Kieffer of the US Geological Survey. Kieffer started working on Mars with the Mariner 6 and 7 missions in the late 1960s, and he's still at it today. In the 1970s he was in charge of the Viking Orbiters' infrared instruments, which measured the the surface temperature of the planet below. At that point, the ice caps were thought to be made of dry ice -- solid carbon dioxide. In winter the caps expanded as carbon dioxide from the atmosphere froze out on to the ground; in the spring they retreated as the seasonal component of the caps sublimed back into the thin air. Kieffer's measurements showed that at the beginning of the northern spring, when the seasonal cap was retreating, its surface was at a temperature of about 150K. This is the temperature at which solid carbon dioxide sublimes under martian conditions, which makes sense -- that is what was going on.

However, in the summer, the temperature of parts of what was left of the cap rose to about 200K. That was too hot for carbon dioxide ice; it was just the right temperature, however, for water ice. Kieffer reasoned that the change reflected the fact that a seasonal layer of carbon dioxide had gone away and a more permanent layer of water ice had been revealed beneath it (the point in the spring on which this transition happens for a given locale is now known, rather charmingly, as that place's "crocus date").

The clinching confirmation of Kieffer's argument came from a second instrument on the Viking orbiters, one that measured water vapour in the atmosphere. After the crocus date at the edge of the permanent cap, when the lower layer of ice was revealed to the summer sunshine, the amount of water vapour in the atmosphere above the cap shot up -- exactly what you would expect if the newly revealed water ice itself was starting to sublime into water vapour, as its temperature suggested it was.

This clever piece of work led to a rash of headlines saying things like "Water on Mars". And quite rightly. As far as I'm aware, no one has ever since suggested that the residual north polar cap left behind when the seasonal carbon-dioxide cap has vanished is not largely composed of water ice. Ice at the north pole is an accepted fact of Martian life, and has been for decades.

It was, of course, conceivable that while there was ice at the north pole there was none at the south, which is the area that the Mars Express results deal with. The Vikings saw no evidence of water ice on the surface in the south, nor any tell tale increases in atmospheric water vapour over the course of southern summers. But a water-free southern cap has seemed unlikely since the results from NASA's Mars Odyssey started to come back a few years ago. The neutron and gamma ray spectrometers on Odyssey showed strong evidence of hydrogen in the top metre or so of the crust in the high latitudes of both hemispheres, which was evidence very hard to square with anything other than ice frozen into the soil. This conformed neatly with the geomorphological evidence -- things like the slumping of slopes and the shapes of craters -- that there was abundant ground ice in the high latitudes of both hemispheres. (The fact that the first Mars Odyssey data basically confirmed what the geomorphology was already accepted as showing didn't stop NASA hyping that data as a great discovery, either.)

As a way of making their evidence seem more groundbreaking, though, European scientists pointed out that Mars Odyssey's neutron spectroscopy was indirect evidence of water (since it actually detected hydrogen) whereas Mars Express's infra-red spectroscopy was direct evidence. (This made it somewhat ironic that the Evening Standard illustrated its front page splash with a plot of the Mars Odyssey hydrogen data. But one shouldn't complain - anything that makes the evening Standard see a European achievement as something "we" did should be welcomed.)

However, the hydrogen spectra are not the only evidence of water from Mars Odyssey. The redoubtable Kieffer, working with Phil Christensen and Tim Titus, used the infra-red instruments on Mars Global Surveyor and Mars Odyssey to find a region within the south polar cap that behaved just as the north polar cap does, and which had thermal properties just like those of water ice. Their work was published online by Science a bit more than a year ago under the title "Exposed Water Ice Discovered near the South Pole of Mars". Various other people looking at similar data have come to the same conclusions.
To describe the data from Mars Express as the discovery of water on Mars is thus more than a stretch. No one has found liquid water. Water ice is old news with respect to the northern cap. And its discovery in the southern cap was published in a peer reviewed journal a year or so ago.

People will undoubtedly argue that this doesn't really matter much in the context of how great it is that the public is interested in Mars, and they could be right. But its still basically wrong to call this the discovery of water, or water ice, on Mars. Its disrespectful of Kieffers work and the work of others. It carries a tone of European triumphalism which, in an area where we hear a lot of American triumphalism, is understandable but still a little unpalatable. And it could be counterproductive. There's a chance that later on in its mission, Mars Express might really find water - liquid water - with its ground penetrating radar. And what will its spokes-people say then?

The real news yesterday was that Europe's first mission to another planet is performing brilliantly, and that its instruments are spectacular, capable of rediscovering in a day or so secrets that had to be teased out through months or years of work in the past. And those instruments, god willing, are now going to send back data for at least two earth years and maybe more. That is truly great news, and it needed no further icing to make it more exciting or palatable.

Cold and Clammy

A fascinating report by the excellent David Chandler in today's New Scientist about the strangely muddy looking texture of some of the ground near Spirit, specifically the places where it seems to have bounced. Apparently some people on the team are speculating there might be some level of brine in the regolith, making it act a bit muddy. Others argue that electrostatic effects may be able to produce the same sorts of textures -- which would be exciting in and of itself. Always cool to see a planet do something deeply unearthly. But the brine explanation is obviously rather sexier, with its implications of possible habitability. The story from the print edition isn't online, but an earlier news report by David looking at other evidence for brine can be found here

For a while I've wondered whether the notion of an early "warm and wet" phase in Mars's history owes part of its appeal to the alliterative simplicity of the phrase. "Warm and wet", or "warmer and wetter", just has a natural ring to it. This may sound silly, but sometimes the way a phrase sounds really does matter. Look at the way debates about the roles of heredity and environment have been shaped by the opposition of "nature and nurture" that Francis Galton borrowed from Shakespeare. Galton found it a "convenient jingle of words". (Shakespeare himself, Matt Ridley informs us, may have borrowed the phrase from Richard Mulcaster, the first headmaster of the Merchant Taylors' school, and the great great great great uncle of the horrendous Boy Mulcaster). "Warm and wet" shaped Mars thinking by insisting that you must have a markedly hotter climate to see effects due to liquid water, and thus any such effects could be relegated to some very ancient climate. In various ways it's becoming fairly obvious that that's not necessarily the case. The ancient climate might not have been that warm, and some recent watery events (for example, the gully-forming process, whatever it is) may have taken place at today's cold temperatures.

The best phrase Ive been able to come up with in an attempt to shake off the dominance of "warm and wet" is "cold and clammy". Unfortunately, its not particularly applicable to the various active but not necessarily very liquid-friendly ideas currently knocking around about ice ages(see this entry for more). If the brine hypothesis takes off, though, maybe "cold and clammy" will be the convenient jingle of the day (he suggested, vainly).

Why Mars?

Last week the international edition of Newsweek asked me to do a little piece for them on Spirit that would, inter alia, try and deal with the "so what?" issue that bedevils a lot of science reporting. The problem -- keenly felt by editors, especially those higher up the chain than the science editor -- is the hypothetical bloody-minded reader who, presented with a neat account of some ownder of the universe or other, just says "so what?" The most common solutions are to try and find implication sof practical import, which skews a lot of science reporting in strange ways, or to try and tie the report into some greater narrative that is considered sufficiently fascinating of itself to pull the report out of so-what land; for Mars, this greater narrative is almost always one involving life.

This piece doesn't talk about life: it just talks about some of the reasons why Mars fascinated people more than most other things in the sky. So it's an indirect answer to so-whatters: it explains why others find the subject interesting, but doesn't try to justify that interest. Newsweek had to shorten it a touch for space reasons; here's their version. Below there's a slightly fuller draft

"If you saw this patch of barren, rock-studded wasteland in the Mojave desert, a couple of hours drive north east of Pasadena, California, you wouldnt look at it twice. After a trip of 300 million miles, though, its a sight for sore eyes. The ecstatic reception that greeted the pictures which Spirit, NASAs Mars Rover, sent back to JPL, the laboratory in Pasadena that runs Americas Mars exploration program, was in part one of simple relief. When NASA tried to land a trio of spacecraft on Mars four years ago it failed with all three, just a couple of months after having lost an orbiter there, too. Another failure would have been a terrible blow for the space agency, and for the scientists at JPL and elsewhere who have devoted years of their life to this project. For the people waiting at JPL even a bad picture would have been bliss; the technically excellent set of pictures  far and away the best yet taken on the surface of Mars  they ended up with was very heaven.

"But apart from the sheer difficulty of getting there and the relief that comes with success, what is it that makes this desert so exciting? What makes it so exciting that scientists see it through tears of joy, so exciting that NASAs web-servers groan with the strain of sending the pictures to eager screens all around the planet? What makes it so exciting that President Bush thinks a promise to send humans to walk in Spirit's tire tracks, at a cost somewhere in the hundred billion dollar range, is something the public is going to be turned on by in an election year?

"Part of the answer is that Mars, though a mere planet, has many of the attributes that make a star  a movie star, that is. For a start, it has a famous face. Its a face weve had a long time to get to know, because its features are discernible from earth with just a modest telescope. That unique attribute  no other planets surface is so open to inspection  means that for the past few centuries idle thoughts about life elsewhere have settled on Mars just a bit more easily on the other planets. Its why "the man from Mars" became and remains the archetypal extraterrestrial, and why the world he came from was the one chosen by the great writers of science fiction and planetary romance, like H G Wells, Edgar Rice Burroughs and Ray Bradbury. The space-age revelation that Marss features  its mountains and craters and polar caps  look pretty good in close up, too, hasnt hurt.

"A striking face alone isnt enough, as any PR person worth her salt can tell you. But Mars has more. It has an easily identifiable character: redness. This may seem pretty trivial (and it borders on the untrue  seen close up under proper lighting Mars is more a sort of yellowish brown than a real red). But redness is something simple that everyone can know about Mars, and people like to think they know something about celebrities. With the exception of ring-girdled Saturn the other planets are lacking in simple, easily-identified attributes. And unlike Saturn  which NASAs Cassini mission will arrive at later this year, having set out back in 1997  Mars is relatively approachable. Its quite possible to imagine astronauts using todays technology to get there in less than a year, land safely, walk and drive around, grow crops in a greenhouse, melt ground-ice for drinking water and so on. While Venus, too, is not that far away, its surface is a hellish place where its hard to imagine a rover or a human lasting a minute. An inaccessible surface beneath impenetrable clouds may give Venus a certain I-want-to-be-alone allure; but if Venus is Garbo, Mars is Lucille Ball. Its attraction lies in a life not that unlike ours, one we can imagine sharing.

"Perhaps the key to Marss appeal, though, is the fact that it has a story. Mars is a planet with a past. The reason Spirit landed in Gusev crater is that many geologists believe the crater was once not a desert but a vast lake. Mars was once very different: wetter and warmer, though probably not as warm as all that. The hows and whens and whys of this great Martian will occupy scientists for decades or centuries, and the story of a world transformed they piece together promises to be fascinating and evocative. This may be why, while many experts see building a moonbase and sending expeditions to Mars as an either/or proposition, President Bush seems set on both. Theres some interesting science to be done on the moon. And as a place to learn the craft of living beyond the bonds of earth the moon has the great advantage of being near enough that you can get back into bondage quickly if things go wrong. But the moon is old, lifeless and unchanging. It may be a great place for new infrastructure, but not for new stories. The president probably understands that stories are the things that excite us.

"Especially when we dont yet know how they end. Just hours after Spirits first pictures got back to earth, image processors at NASA and elsewhere had produced three-dimensional versions of them. But our imaginations had already gone one better. In our minds eyes we added a fourth dimension of time, a future that stretches through the screen and over the horizon, a future that Spirit will soon be rolling into. Gusev crater, and Mars itself, may be empty now  but the future is always empty before we get there. Mars is a real, solid, kick-a-rock-and-youll-stub-your-toe place and at the same time a dream of whats to come. A future we can see but not yet reach, a future full of mystery, a future unlike the past. Thats whats exciting."

High Spirit

I haven't blogged yet about Spirit mainly because I don't have much to add to everyone else's wow-that's-great feelings. The landing's obviously an enormous achievement. But at the same time it's just the prologue. There are months to go, and the real highlights are surely yet to come (though they're unlikely to get anything like as much coverage).

I have been thinking fond thoughts of Nathalie Cabrol, though. Nathalie started working on Gusev crater as a feature that might once have been filled with water when doing her doctoral research in Paris in the 1980s, and soon began to think of it as a landing site. I think she first proposed it as such in public at a meeting in the Soviet Union, maybe around 1989. Since moving to NASA's Ames research center she and her husband Edmund Grin have kept at it, wringing every scrap of interpretation they could out of the Viking pictures of the crater. They've ceaselessly promoted it as a potential landing site, occasionally to the irritation of some of their peers. At a meeting in 1999 to discuss possible landing sites for a probe that was later cancelled, Nathalie put various people's backs up by insisting on discussing Gusev even though, for engineering reasons, the probe in question simply couldn't go there. Her response was that if a probe couldn't go to a great landing site like Gusev, then it was the probe's engineering that was at fault, not the scientific rationale for going to Gusev.

And now she's got her wish. I asked a mutual friend by email the other day if she was actually walking on air as she looked at the pictures. No, he said. But she's walking tall. Good for her. And Edmund. And all the rest of them.

And so it goes

Back to Camden for the last time this afternoon, to see if Mars Express, now in a suitable polar orbit, will pick up anything as it passes over Beagle 2�s presumed landing site. The press room is absolutely packed, with at least a dozen TV crews. Colin is, for the first time, looking and sounding tired, maybe beaten. His tongue slips, only in minor ways, but enough to break something of the magic of his patter as he talks us through what could happen on this pass and in the future. Then, at three o�clock, David Southwood, ESA�s head of science, speaks to us over a poor-quality TV hookup from mission control in Darmstadt. It�s not good news, and Southwood�s not putting a particularly brave face on it. There�s no trace of Beagle in the data from Mars Express.

There are still some plausible scenarios in which Beagle is pretty much OK, but having difficulties in making contact. Over the next month they�re going to explore these possibilities. But though they�re plausible, the overwhelming likelihood now has to be that something went drastically wrong during the entry, descent and landing.

The loss has been oddly gradual. Those more closely involved could probably say when they began to feel that hope was forlorn, but to a more casual observer it�s hard. The lack of contact at Christmas was a disappointment but not fatal; the near certainty of loss today was no surprise, really. And for me, at least, there was no clear moment in between when hope went through a step change from high to low. It just faded until it was more a memory of hope than hope itself. And now the memory of the hope is all there is.