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The Planetary Society Blog
By Emily Lakdawalla
Mars Sample Return
Sep. 21, 2006 | 06:10 EDT | 10:10 UTC
by Mark Adler
In this blog entry and the next, I will summarize my horribly failed attempts at bringing rocks back from Mars. The idea is to give you, our faithful blog readers, a little insight into the perils and pitfalls of trying to bring these grand and glorious space missions to reality, from a personal point of view. This story is the depressing downside of what goes on. If you'd like a story with a happier ending, though still with lots of perils and pitfalls, I recommend Steve Squyres' Roving Mars book, which details the story of the Mars Exploration Rover project. Now back to the Mars Sample Return story (so far).
At some point after I had gotten through several somewhat unrelated and largely unplanned college degrees, I actually starting thinking about what it was I wanted to do with my life. (I hear that most people try to figure that out before getting the degrees.) I wondered then, and still wonder now, how did we get here? By "we" I mean creatures who are capable of asking questions like "how did we get here?" It all seems so magnificently bizarre. I didn't think I could answer the question of course, but maybe I could contribute to some small part of the answer. It is a remarkable luxury that we can spend time on such questions, as opposed to, for example, having to hunt and kill dinner.
The real mystery in my mind is not the evolution of intelligence from single-celled organisms, though there's obviously a lot there to learn, but rather how the single-celled organisms came to be in the first place. None of my degrees was in biology or even chemistry, so I took a different tack on how I might contribute. I figured, as many others have, that if we could find another example of single-celled life distinct from Earth's, then we'd be getting somewhere.
It's hard to figure out anything from just one example. So where to look? Clearly not on Earth, since we seem to have a single biology that has infested the entire planet from stem to stern. There really is only one example of life here. That leaves some place other than Earth. Somewhere out there. So I decided to apply my degrees in physics, electrical engineering, and mathematics to exploring space.
The center of gravity of space exploration was at JPL, so that's where I went.
In early 1996 Donna Shirley (currently on the Planetary Society Advisory Council) asked me to work for her on the newly-formed "Mars Exploration Program" at JPL, which she was managing. I was to be the "Mars Exploration Program Architect". Among other things, I was to figure out how to bring selected samples of Mars rocks to Earth, and do it affordably. The idea is that if you pick up and deliver the right rocks, then by bringing to bear the full arsenal of Earth's scientific instruments on those rocks, you can find evidence of an extinct single-celled biology on Mars and learn something about it.
If it was ever there, that is. In fact, that is pretty much the only way to get a definitive answer to such a question in a reasonable amount of time. If you try to do it on Mars and the instrument says yes, there was life, then someone will come up with a challenge to that finding that will require sending another instrument to Mars to respond to that challenge. At best, six and a half years later (three Mars launch opportunities). Then the same thing happens again with that instrument's results. This could go on for some time. If you have the rocks here on Earth, then that challenge/response cycle time is much faster, on the order of months, and you can apply much more sophisticated instruments and sample processing. Including instruments we haven't invented yet. As Carl Sagan, one of the founders of the Planetary Society, once said; extraordinary claims require extraordinary evidence. In fact he said that a few months after I joined the Mars Program.
In August of 1996, the rock hit. A paper was published about the now famous ALH84001, a meteorite from Mars found in Antarctica. The claim was that several different lines of evidence all resulted in the conclusion that the rock contained evidence of ancient biological activity on Mars. Fortunately I had a few months head start working on Mars Sample Return, since now the interest in that mission suddenly got intense. In the meantime, using the process described above, many laboratories did their own analyses of pieces of ALH84001 to substantiate, or not, the claims. Even though the subsequent investigations showed that the necessary "extraordinary evidence" was unfortunately not there, the interest in Mars Sample Return did not subside. In fact it increased.
"Hey, wait a minute" you're thinking. "If you already have pieces of Mars here, why do you need a Mars Sample Return mission?" First off, they're not the right rocks. We'll need to go to one, or more likely several, very carefully selected spots on Mars to have even a fighting chance of finding the evidence we're looking for. We don't get to pick the rocks that come to us by accident. Those can come from anywhere. Furthermore those rocks get contaminated on Earth before we find them and pick them up. We should of course continue to do the really cheap Mars Sample Return missions to Antarctica, but unless we're really lucky, that's not going to give us the gold.
In 1997 we had several stunning successes at Mars, the Mars Pathfinder lander and Sojourner rover, and the Mars Global Surveyor orbiter. That really bolstered everyone's confidence that we could do even more ambitious things at Mars and succeed. Like Mars Sample Return.
So we had the motive and the means. We just needed the opportunity.
We developed a way to scale up the Mars Polar Lander design to land a much larger payload. We came up with a rover and a rocket to put on the lander. The rover to get the rocks, and the rocket to put them into Mars orbit fit in a grapefruit-sized container. And we designed a spacecraft that could go into orbit around Mars, find and capture the rock container, and bring it back to Earth. How hard could it be?
Even in those illusionary faster-better-cheaper days, it was still a very expensive mission. Fortunately the French space agency, CNES, decided to partner with us on the mission, providing a large Ariane V launch vehicle, the return orbiter, and a really talented team. NASA bought into the joint mission, and so in 1998 we were off and running with the first real Mars Sample Return Project, planning to launch in 2003 and 2005. I was the Mission and Systems Manager and Chief Engineer on the project. Below is a piece of artwork depicting that mission that I had commissioned for the project. (It was my idea to hide the rover behind a rock for the launch. :-) )
Mars Sample Return Credit: NASA |
You probably know the next part of the story. In 1999 we lost both the Mars Climate Orbiter and the Mars Polar Lander during their critical events at arrival. All that blustery confidence that we had built up from Pathfinder and Mars Global Surveyor vanished in an instant. We no longer had any business thinking that we could pull off something as complicated and risky as Mars Sample Return. The project was cancelled in 2000, a few months after the Mars Polar Lander failure. The artwork and a lot of designs and documents was as far as we got.
At that point, Job #1 was to regain our confidence. To get back in the saddle. I pulled together a small team to propose what became the Mars Exploration Rover project with exactly that objective. Fast forward four years (see Steve's book for the details), MER has succeeded beyond our wildest expectations, and our confidence has been restored. In my next entry, I'll cover my second swing at Mars Sample Return starting in 2004.
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