Tuesday, May 22, 2007

1200 Days on Mars

There was exciting news from NASA yesterday as the Spirit Mars rover has accidentally discovered silica-rich soil, a mineral that likely could not have formed without the presence of water. It's a strong further clue that Mars was once warmer and wetter than it is today, and might (or might once have) supported some form of life.

Which is pretty cool stuff, but it isn't really what this post is about. What struck me was a quote from Steve Squyres of Cornell University, leader of the rover team in a TimesOnline Article. He says, "This is a remarkable discovery. And the fact that we found something this new and different after nearly 1,200 days on Mars makes it even more remarkable. It makes you wonder what else is still out there."

Indeed. We've been poking around the planet we live on for many thousands of years and it continues to surprise and mystify us. Which is why I'm always appalled at detractors who dismiss the idea of a return to the Moon because, "we've already done that."

What surprises me most is that I hear this not just from opponents of space exploration, but from space advocates as well. Many of them simply see the Moon as a nothing more than a distraction from their real goal of a manned expedition to Mars. "Been there, done that, got the tee-shirt and some rocks. Move along. Nothing to see here."


Now, admittedly, the Moon is in many ways a far less interesting and complex place than Mars. But we still know so little about it. The assumption that the Apollo missions "saw everything there is to see" is simply absurd, and some people don't appreciate how short a time they were there, and how little they saw while they were there. First, let's look at the numbers:

Apollo 11

Time on Surface: 21 Hours, 36 Minutes
EVA Time (time spent outside the spacecraft actually doing something): 2 Hours, 32 Minutes

Apollo 12
Time: On Surface: 31 Hours, 31 Minutes
EVA Time: 7 hours 45 Minutes

Apollo 14 (Apollo 13, of course, suffered a crippling explosion on the way to the Moon and was unable to land)
Time on Surface: 33 Hours, 30 Minutes
EVA Time: 9 Hours, 22 Minutes

Apollo 15

Time on Surface: 66 Hours, 55 Minutes
EVA Time: 18 Hours, 33 Minutes

Apollo 16

Time on Surface: 71 Hours, 2 Minutes
EVA Time: 20 Hours, 14 Minutes

Apollo 17

Time on Surface: 75 Hours
EVA Time: 22 Hours, 4 Minutes

So that's it, a total of about (by my sometimes shaky math) about 80 and one half hours on the Moon. And a lot of that was spent climbing up and down ladders, opening and closing hatches, stowing and unstowing gear, figuring out how to walk and work (every flight was essentially a training flight). Three days and change. Almost seven man days, if you're generous.

Yeah, that's just the manned part, but it isn't like there's a huge body of unmanned exploration to back it up. The U.S. sent seven unmanned Surveyor landers in advance of the Apollo program. Five of these landed. The others crashed. These were frightfully primitive by current standards, comparing to the Spirit and Opportunity rovers about like a rusty skateboard compares to an SUV. They had a crude TV camera, a few simple instruments, and some had a simple arm that seemed to have been borrowed from a carnival claw-machine.

This is in no way intended to be dismissive of the accomplishments of the talented people who built this thing. It's simply a product of its time, relatively early in the TV era, and the dawn of the computer/microelectronics age. Compare it to then-contemporary dial phones, televisions with vacuum tubes, and room-sized mainframe computers with 8k (no gigs, not megs, kilobytes) of memory.

The Russians later two sent rather more sophisticated landers that included remotely operated rover vehicles. Technical wonders at the time, and a bit more comparable to Spirit and Opportunity, they're still primitive by modern standards.

Even ignoring the total time spent in exploration, keep in mind that in all cases, the landing sites were picked for safety first, and their scientific interest second. This is especially true of the early Apollo missions. And in any case, that's a handful of sites on a globe with about the same surface area as the United States, Russia and Canada combined. And the sites chosen aren't even a random sampling. Even ignoring the safety issue, none of the sites were on the lunar far-side, which has a surface completely (and perhaps a little mysteriously) different than the one we see in our sky every night. None of the landings took place near the poles, where frozen water may still exist.

What do we know about the Moon? How much have explored? Slightly more than none and zilch. We have barely been there. We have not done that. We don't even know where tee-shirts are sold. But we did get some rocks representative of fairly safe landing zones.

Okay, again, this has to be taken in perspective. The Apollo program was a monumental accomplishment, a wonder if its age or any other. But it ended too soon, and it should have been only the beginning.

I realize too that, although what I'm advocating is a manned return to the Moon, this could just as easily be used as an argument for unmanned exploration, something I'm certainly not against. Quite the contrary, I think any manned return to the Moon should happen in conjunction with a strong program of unmanned exploration. In fact, the Moon could be an ideal laboratory to study how to dovetail the use of man and machine in exploration of another world, lessons that could be invaluable in planning the much longer, dangerous, and yes, more expensive trip to Mars.

Yes, I think we should go to Mars, with robots, and eventually, with human explorers. But one thing I'm not sure the Mars advocates have considered is, "what next?" Going to Mars is going to be hugely expensive and dangerous, and while it is certainly worth doing, it seems doubtful that it will in any reasonable term become routine. In fact, it's possible it could be a one-shot deal. At most, it seems likely that a Mars program would consider of no more than a hand-full of manned expeditions before costs became prohibited.

Yes, there will still be much of Mars to explore, but does that matter if we can't afford to explore it? And as we have seen with the Moon, the presence of unexplored territory is no certainty that we will follow through once the novelty wears off. What if we "go there, do that?" Even if cost were no object, other than asteroids there are few obtainable targets for manned exploration in the solar system without great leaps in propulsion technology.

A stepping-stone approach to Mars via the Moon would allow us to establish a more permanent off-world foothold, one that might better prepare us for that great leap, and allow us to more affordably continue our off-world explorations afterwards. The Moon is not a distraction from Mars. It is both a testing and training ground for further off-world exploration, and a sustainable foothold off this fragile world of ours. A long-term manned presence on the Moon greatly increases the possibility that we will not only successfully go to Mars once, but that we will one day return again and again, perhaps eventually to stay, perhaps to map and explore all those, far, undiscovered lands.

And I wonder what unexpected secrets we will find, on our 1200th day on the Moon? Only 1196 and 2/3rds to go.

(All photos NASA/JPL)