Tschuess, Shuttle!

Clearly with a week having passed since touchdown, my farewell to the space shuttle program is grossly overdue.  I actually missed watching the event live, as I was off on a camping trip in some beautiful New Hampshire woods.  

Atop of the usual excuses, it's been a bit hard to figure out what I could write that was different than so much that has been written.  It would seem that every major media outlet opined on the subject, and most did a decent job in hitting the key points. 

Vostok & Columbia

It has hardly gone unreported in the media that today marks the 50th anniversary of the manned spaceflight and the 30th of the first space shuttle launch.  It was an accident of scheduling delays that put that flight on the 20th anniversary of Gagarin's, but what an appropriate synchrony that is!  My own contribution herein is to pen two quick capsules of two books that deserve longer reviews: Two Sides of the Moon and Riding Rockets.  If you have a strong interest in the history of spaceflight, you should consider reading each of these if you haven't already.  The only caveat I'll throw in is that if you have a young friend who fits that category, but you do not, you should at least skim Reading Rockets before passing it on; some of the content (and most of the humor) is of a mature nature.  While neither book is primarily about either of the events commemorated today, both bear on it.

Remembering the 27th, 28th & 1st

When I was a junior in high school, on a day much like today, I wanted to stay home and watch TV a bit, so I was hoping the wintry weather would generate a snow day. I didn't often wish for this, as my childhood love of snow had subsided substantially (though I would sometimes ski through my yard), but on this day I wanted to be home. Winter and the superintendent, however, did not cooperate and we had only a delayed opening, and hooky was out of the question in my family so off I went.

And so I was sitting in Mr. Schmidt's chemistry class that morning. He was a nice man, but that class did very little to prepare me for a life on the periphery of chemistry, except that he did an excellent job of outlining the early 20th century revolution in chemistry & physics. I do not remember what he was talking about that morning when Mrs. Kurtz, the Biology II teacher, came in and commented on a news event. We all nodded, given we expected the news -- but then she restated herself as we had not heard her, and Mr. Schmidt got out the TV in his closet and I found myself watching TV that morning -- exactly what I had hoped to watch on a snow day but also nothing I had ever imagined or could have remotely hoped to watch. For that restatement was: "No, the space shuttle blew up!".

When my boy was three we were going one weekend to take him to the Boston Children's Museum, a wonderful place for a child of that age to explore and run around and have fun. As a bonus, we would ride the subway there and oh how he loves to ride trains. It was again a winter day and I drove the usual route to Boston & there is a spot on I-93 where you come out of the relatively untouched beauty of the Middlesex Fells and the skyline of Boston suddenly appears. It was in that spot that I heard the report on radio whose meaning became instantly clear, and I semi-silently cried "No!" -- an extended loss of radio contact with a space shuttle could not ever end happily.

We are in the midst of that grim week of anniversaries for NASA; yesterday marked the 42nd anniversary of Apollo 1, today the 23rd anniversary of the loss of Challenger and Sunday is 6th anniversary of the loss of Columbia. Only one of those events has any obvious connection to this time of year.

For as long as I can remember the space program has had an outsized influence on my imagination. My career path did not take me in a good direction to go to space, but I still think about it almost daily. In some ways these three disasters are completely removed from what I do, but in other ways they are not. I do subscribe to Edward Tufte's argument that poor data visualization helped enable the Challenger disaster, and while my plots do not carry such weighty implications I still must be ready in case they ever do. All three of these were hardware failures, and I do software, but software failures have caused unmanned probes to be lost and manned missions to go awry.

But of all else, it is important to remember those who pushed the limits and did not return. We must remember who they were and why they died, as they died doing important things and they died because humans make mistakes. Grissom, White & Chaffee were doomed by a design from which escape was impossible and fire likely. Smith, Scobee, McNair, Onizuka, McAuliffe, Jarvis & Resnik died when a machine was run far outside its normal operating regime. Brown, Husband, Clark, Chawla, Anderson, McCool and Ramon died from a design which was not well matched to the materials used to construct it.

We recently learned some more details of the Columbia accident: how the astronauts never realized the disaster approaching them, but how pilot McCool worked calmly to deal with systematic failure just before it killed him. I wish I could have such coolness under stress.

Isn't The Great Filter something in the Whatman catalog?

Twice in the last week the Globe has run pieces on a concept called 'The Great Filter', once on the Op-Ed page and now in the Star Watch astronomy column. I've read both, and the pseudo-statistical thinking in them just irks me.

The headline on the star watch column suggests the hubris that is perhaps what is goading me: "Why a microbe on Mars would change humanity's future". I'd completely agree that discovering microbial life on Mars would be exciting, but where it goes from there is bizarre.

The gist of the argument can be found in this quote

If life arose independently twice in just one solar system, it would mean that the life formation process is easy and common. Life would be abundant everywhere. Most starts have planets, os the entire universe would be teeming with living things.
Good news? No. The chance for humanity's long-term survival would immediately look worse.
Follow carefully now. Whether or not simple life is common, we know that intelligen, technological life -- like us -- is probably rare. Otherwise, goes the arugment, it would have noticed such a good planet as Earth and come here to colonize as early as hundreds of millions of years ago

.
Given that we haven't yet found signs of other advanced life (or any life) elsewhere

If life is common, something apparently stops it from developing to the point of gaining interstellar travel and settling the galaxy...Apparently, some kine of "Great Filter" preveents life from evolving to the point of getting starships. If the Great Filter lies early in evolution -- such as if the origin of life itself is a rare fluke -- then we, humanity, have already gotten through it. If the Great Filter lies ahead of us -- such as, for instance, if technological civilizations always destroy themselves as soon as they get to power -- then we have no more chance of making it than all the others who have failed and left the cosmos silent.
The more advanced the fossils of living things that Mars may hold, the greater the chance that the Great Filter lies not behind us but ahead.

Okay, just where to start. First, the current Mars mission finding life on Mars is a far cry from finding that life arose independently on Mars. We know that rocks make the transit occasionally, and while we think we sterilized all the probes, the possibility that any life form found really shares a common heritage must first be ruled out. Gary Ruvkun has suggested an experiment for a future probe to look for & sequence ribosomal RNA (if I remember correctly); that would be an appropriate follow-up.

There's also the problem of an N of one: Mars is one planet. Maybe you count an N of 2 with Earth as the second case, though since you're trying to predict on it that's a case of training on your test set. Mars is hardly an independent sample; the same solar system, which may or may not have some unusual properties.

But perhaps more irksome is conflating the reasonable idea that there are difficult barriers against spacefaring species to arise with the rather silly one that there is a single "Great Filter". Mars is a particularly poor example, as we would have a good guess what the filter is there: the planet quit being a nice place to live.

How improbable is life? How often do planets get life but it stays unicellular? How often multicellular but never ambulatory, sentient beings? How often do those sentient beings come up with some way to prevent travel to the stars -- a religion that forbids it, self-extermination (which our species has toyed with). Perhaps some inhabited planets have a super Van Allen belt which dissuaded their residents from becoming star travelers. Perhaps there are intelligent cultures far away -- but with a timing such that their signals can't yet reach us.

The fact is, any estimates of the probability of any one of these (or anything else you can imagine) are nothing but personal priors, wild guesses without much basis in fact. Feel free to make them, but spare us the headlines about predicting doom and gloom.

Space, the final bio-frontier?

In case it hasn't been obvious from the occasional post, I am a spaceflight aficionado. As a very young child I watched some of the last moon landings. Many hours of play were spent imagining riding a rocket, playing with toy rockets, and building Lego spaceships.

At some point I realized I really didn't quite have the Right Stuff. Clearly I was never going to cut it as a pilot (I carry scale models of Hubble's corrective lenses on my nose daily), and in the end my scientific interests weren't really going to support traveling to space. So it became purely an observational hobby, though the dream has been rekindled a bit by the notion of buying a rocket ticket (alas, 2001 has come-and-gone without the vision of 2001). When Millennium changed travel agents a few years back & we needed to fill out new travel preference forms, I put Virgin Galactic as my preferred carrier.

A more inner struggle, one reflected in much of the space community, is the appropriate role of humans in space, or perhaps more pointedly, of government funding of humans in space. It is one thing for some gazillionaire to pay multi-millions to take a joy ride (anyone want to spot me $50M for a week PLUS a spacewalk?); it's another for governments to continue to spend billions to put people up there. Manned flight is thrilling, but robots tend to get more data.

An item in The Scientist (free registration may be required) points to this debate again, and close to my scientific home. Lobbying is firing up again for biology research in orbit, and given that the company (Spacehab) lobbying for it builds manned research gear, they're pushing the manned angle.

Space research has yielded many earthly benefits, but they're mostly in areas such as communications & remote sensing. It is difficult to really prove a case for very many other areas. Spaceflight remains rare, unpredicable & expensive, three qualities that few like to associate with their research programs.

Two biotech claims are advanced to support space research. One is the long-standing issue of crystallography -- the claim is that crystals for X-ray diffraction studies can be grown in space that are either higher quality than ground samples or which simply can't be made on the ground. The other is a very new claim of vaccine research.

If anyone knows of a good, balanced (not in the Fox News sense!) review of space-based crystallography, I'd love to have a pointer. I'm not in that community, but my general impression is that while useful data has been collected on space-grown crystals, it really hasn't taken that community by storm. Perhaps if flights were cheap & frequent it could, but other approaches such as high-throughput condition screening have had a bigger impact.

The vaccine claims are based on a paper published last year in PNAS (also covered in The Scientist) which found that spaceflight changed some key gene expression programs in Salmonella and that the space-flown bugs were more virulent. A quick scan suggests that the paper is reasonably well done on the transcriptional profiling side (both biological & technical replicates). But, it also points to the challenge of space research -- when is the next flight opportunity to determine how general the effect is?

I do believe there are a lot of fascinating fundamental questions to ask about biology in space. Many would be in the developmental & cellular world: to what degree does gravity influence various developmental processes. Some other research might be less about space & more about behavior: Skylab astronauts had spiders spin webs, and it took a number of trials for the spiders to learn to do it in Zero-G. It could be a fascinating way to study such behaviors & how an animal adapts to a changed environment. But, most space biology questions have an importance scaled to our commitment to manned presence in space. I'm a bit skeptical that the Salmonella experiments really help understand virulence on the ground (or more importantly, are going to be generally relevant -- but sometimes it doesn't hurt to be lucky!), but I'd sure want that line of work driven hard if I was going to spend months in space!