The New York Times published an editorial (registration required) today on Obama’s changes to the space program. I don’t claim that the NY Times editorial board has great scientific insight (though their paper’s science journalism is among the best in the country), but they express a few misgivings that I’ve heard elsewhere, especially from NASA folks and others in the planetary science community.
If done right, the president’s strategy could pay off handsomely. If not, it could be the start of a long, slow decline from the nation’s pre-eminent position as a space-faring power.
We are particularly concerned that the White House has not identified a clear goal — Mars is our choice — or set even a notional deadline for getting there. The National Aeronautics and Space Administration and Congress need to keep the effort focused and adequately financed.
Yes, on both points. The complaint I’ve heard most is that administration’s approach may be sound, but WHAT IS THE GOAL? The press release had grandiose rhetoric but no stated exploration goal. Are we going to Mars? Are we stopping off at the Moon, even if we’re delayed by a few years? Are we visiting near-Earth asteroids or the moons of Mars (the objects with low gravity wells suggested in the Augustine Report)? Any of these would be OK with me, but without a plan, it all sounds suspiciously like the Obama administration wants to change Bush’s plan for the sake of doing so (which is far from unprecedented) or that they don’t hold science beyond climate and medicine to be much of a priority.
The editorial makes another point I’ve been hearing, but less often from the planetary science people as from science blogs and news sites, and that is that the Moon return mission as planned (or any Moon mission) would have limited value. On this I disagree. Another quote:
A lunar expedition would be of some value in learning how to live on the Martian surface but would not help us learn how to descend through Mars’ very different atmosphere or use that planet’s atmospheric resources effectively. Nor would it yield a rich trove of new scientific information or find new solutions for the difficulties of traveling deeper into space. [italics mine]
Like I said, if you don’t want to go back to the Moon, fine – there are good arguments to be made there; even within NASA and the larger community there were many who thought we should have set sights directly on Mars or near-Earth asteroids. I think, however, that to say the Moon won’t “yield a rich trove of new scientific information” is just wrong. For some background, you can browse the online edition of The Scientific Context of Exploration of the Moon, a publication of the National Research Council. The Moon has no plate tectonics and no weathering processes (other than the “space weathering” I wrote about here as it relates to asteroids) and so it contains the most complete picture of 4.5 billion years of solar system history. This includes records of impact flux which can refine (or disprove) the Late Heavy Bombardment model (concerning a peak of impact activity around 3.9 billion years ago) or the late veneer hypothesis (concerning the early arrival of water on the Earth and Moon by meteorites or comets). The same impact record coupled with frozen volatile deposits detected by LCROSS and Chandrayaan can tell us something about later impact flux and the composition of the impactors. This record has been almost entirely wiped from the Earth’s surface, and the arrival of water and the occurrence of cataclysmic impacts have a huge relevance to the origins of life. Furthermore, the Moon preserves its original crust, however fractured, and its study can illuminate our understanding of planetary differentiation and crustal formation.
The public hasn’t been sufficiently exposed to the wealth of information gleaned from returned Apollo samples. These materials are still under intense study of all kinds, but all Apollo landing sites were centered on the Procellarum Region – an interesting but not wholly representative part of the Moon. Rare as they are, lunar meteorites are another rich source of information, but they lack context because we don’t know their original location. Remote sensing by orbiters has expanded our knowledge of the Moon’s composition away from the Apollo landing sites, but these data open up whole new frontiers of questions that are best answered by careful directed fieldwork. Robotic rovers and sample return missions would be a huge step in that direction, but with foreseeable technology they fall far short of a single trained human being.
There are many reasonable arguments for skipping the Moon and going straight to Mars or elsewhere, and I’m happy to listen to them. But the Moon’s lack of scientific value is absolutely not one of them.
0 comments:
Post a Comment