Chinese Want To Capture an Asteroid 481
geekmansworld writes "The Chinese want to capture an asteroid into earth's orbit and mine it. From the article: 'At first glance, nudging an asteroid closer to Earth seems like one of those "what could possible go wrong" scenarios that we generally try and avoid, and for good reason: large asteroid impacts are bad times. The Chinese, though, seem fairly optimistic that they could tweak the orbit of a near-Earth asteroid by just enough (a change in velocity of only about 1,300 feet-per-second or so) to get it to temporarily enter Earth orbit at about twice the distance as the Moon.'"
University research paper. Bad Slashdot (Score:5, Informative)
It's a research paper. It's 2 guys looking at the possibility for the sake of their course grade/diploma. It doesn't mean there's a plan, or a will, or even a wish. Come on editors, click through your links and understand your articles before approving crappy summaries.
Not the Chinese (Score:2, Informative)
The headline makes it sound like this is a plan of the Chinese government, or a desire of the Chinese people as a whole. Instead, according to the article, it's an idea from two researchers at a Chinese university. It is just an idea at this stage, not something anybody has expressed a desire to do.
If it was "black people" or "the Jews" instead of "the Chinese," we would be offended by this headline. But since the Chinese government is unpopular in America, it's a good chance to take a subtle and unwarranted jab at "those crazy Chinese, who will probably kill us all."
Re:Economic worth (Score:4, Informative)
Whyever would you return the output of your mine to Earth?
The primary value of a bug chunk of rock and metal in orbit is that it's cheaper to make things from it than to haul the same amount of metal into space.
Right now, one of our big limiters on space activity is that we have to move EVERYTHING out of a deep gravity well to get it into space at all. If we can eliminate the need to move, say, the structural mass of a solar power satellite into orbit, we can reduce the cost of solar power satellites by an order of magnitude or three.
Ditto anything else we want up there....
Re:One more thing China (Score:2, Informative)
This isn't 'The Chinese' (as in the Government) its some Chinese guys at a university in Beijing with a crazy idea they posted on Arxiv. Arxiv is not the place that the Chinese government will be posting their world domination plans.
Do you really think that this type of endeavor could ever take place without governmental involvement? The resources required would be astronomical ... and any government worth their salt would milk this for every drop of national pride (and then some).
This can't happen without the government getting involved because "Two Guys From a Chinese University" is not a viable entity for this type of operation.
Re:China, don't get ahead of yourself. (Score:1, Informative)
Re:Chinese resource grab reaches new heights (Score:4, Informative)
First off, all of the Lagrange points are further from Earth than the moon.
Not quite.
Notice this diagram of the earth-moon system at:
http://en.wikipedia.org/wiki/Lagrangian_point [wikipedia.org]
Points L3, L4 and L5 are all at very nearly the same distance as the moon. L1 is actually closer. Only L2 is significantly farther away. Technically, the more the biggest body is larger than the secondary, the more the 3, 4, and 5 points will tend to fall slightly beyond the secondary's orbit, So for the Sun-Earth system, the L3, L4, and L5 are slightly outside Earth's orbit. But, the Earth is not as much proportionately greater than the Moon, and the 'points' are actually larger than pure points so for the Earth-Moon system, L#, 4, and 5 fall partly inside and partly outside the Moon's orbit.
You are, however, quite right that putting an object at a Lagrangian point doesn't keep it there. The range of velocities that are even semi-stable is pretty narrow, and for points L1, L2, and L3, the stability is in a plane perpendicular to the two major bodies, and there really is no gain in stability along the line between them, Every time we have parked a satellite at one of these points, it has been by using station keeping thrusters to give it an occasional nudge to keep it there. It's cheap on thrust, but not free. You're also right that the points have naturally attracted stuff already and tend to be cluttered spots. I don't know if that really affects costs or risks - there have been solar observation satellite missions to the sun-earth Lagrangian points, where the same problems should apply, and these have worked well so far.
Because the orbits of the various major bodies are elliptical, the Lagrangians aren't really points. If there weren't other planets and such around, the orbits would be roughly kidney bean shaped, but since there are, objects tend to be pretty close to stable in complex orbits called Lissajous orbits. Making those fairly large may be a way to avoid some debris.