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Asteroid Missions May Replace Lunar Base Plans
An anonymous reader alerts us to a story about efforts to modify the United States' space exploration plans to focus on asteroid missions rather than a lunar base. Scientists, astronauts, and former NASA division directors will be meeting next month to develop an alternative to the Bush administration's Vision for Space Exploration. We have previously discussed the possibility of a manned asteroid mission. Quoting:
"Numerous planetary managers told Aviation Week & Space Technology they now fear a manned Moon base and even shorter sorties to the Moon will bog down the space program for decades and inhibit, rather than facilitate, manned Mars operations--the ultimate goal of both the Bush and alternative visions. The first lunar sortie would be flown by about 2020 under the Bush plan. If alternative-vision planners have their way, the mission could instead be flown to an asteroid in about 2025."
If true, this is very good news. Asteroids, the smaller and more numerous ones being undifferentiated bodies, have considerably more scientific value than the moon. It's actually much easier to rendezvous with and return from many asteroids than to land softly on the moon and return. The moon is relatively large, with a big gravity well, and without an atmosphere, aerobraking is impossible. Landing from lunar orbit and takeoff to orbit each require delta Vs greater than 2000 m/sec. Entering and leaving lunar orbit takes even more. Asteroids require earth escape, but that is only slightly more than reaching the moon's high altitude (400,000 km). The velocity change required to rendezvous with the asteroid could be minimized by careful choice of asteroid and launch window.
Asteroids would take much more time to reach, and a mission could not be quickly aborted in an emergency. The communications lag would also be significant; real time conversations would be impossible and communications might even be blocked entirely by solar conjunction for a few days at a time. These are challenges for human space flight, but not insurmountable ones.
Good, I hope that they succeed in changing that strategy. For any colony to actually be useful and self-sustaining, there has to be some hope of an economic return on investment. The driest deserts and coldest tundras here on Earth are like tropical paradises compared with anything outside our planet, whether that's the moon, Mars, or a space station floating around the asteroid belts. Any space colony would be heavily dependent upon imports for survival (e.g., food, clothing, natural resources, manufactured goods, etc.). That will require a roughly equal amount of exports to balance trade, probably in the forms of valuable minerals and manufactured goods that are best made in microgravity environments. That becomes rather difficult to accomplish if you're stuck in a gravity well like a planet or relatively large moon, because lifting those items back out would be prohibitively expensive. We need to stop obsessing over planets and moons, just because we happen to be bipedal and live on a planet now. Asteroids are the way to go.
A robot is not a scientist. The result of each experiment informs scientists how to construct the next experiment. This is easy if they live on the moon, it can take a decade if they don't.
If we can put a man on the moon, why can't we shoot people for Apollo-related non-sequiturs?
In the book, "The Case for Mars" the author, also the creator of the Mars Direct Plan, argues skipping the moon all-together and go straight to Mars. This is because Mars is full of resources that could be used to make a self sustaining colony, whereas a Lunar base requires everything to come from Earth. Differences between a Lunar Base and the ISS? The Lunar base is on the Moon, and on the Moon you can do geology and astronomy particularly well; on ISS, there's not much useful science.
I'm not sure cruising to asteroids is the answer, but at least there are probably lots of interesting and diverse resources, and the missions could be made lightweight(no lander required). The geology of Asteroids is probably alot different than the Moon's because there was no volcanic past or differentiation. But my opinion is, cut to the chase, go to Mars, its the most interesting thing out there.