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Space Science

Tilting at Asteroids 37

Posted by michael
from the f-equals-ma dept.
JimPooley writes "The European Space Agency are conducting a feasibility study into a future mission to knock an asteroid off course. A Spanish company are planning the 'Don Quixote' mission to launch a pair of spacecraft at an asteroid. One hits the asteroid, while the other monitors it to see what happens."
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Tilting at Asteroids

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  • by Xilman (191715) on Friday August 09, 2002 @11:36AM (#4040043) Homepage Journal
    More accurate, perhaps, but not as much fun.#

    To be serious: I'm not convinced its either cheaper or easier. If the impactor is nothing but a solid lump of metal with some terminal guidance on board that is going to be a lot cheaper and simpler than a robot big enough and smart enough to paint several square kilometers of asteroid surface. Admittedly, the observation probe has to be smarter and so more expensive.

    What is not clear to me is why the observer has to hang around for so long and so far away. Why can't it just carry a radio beacon and hard-land on the asteroid after waiting for the impactor's immediate effects to dissipate. Thereafter the asteroid's position and velocity could be determined from earth-based observations with very high accuracy and for decades afterwards. That's pretty much what we're doing with the old Pioneer and Voyager probes.

    Paul
  • by Mad Bad Rabbit (539142) on Friday August 09, 2002 @12:24PM (#4040419)

    Xilman writes:

    To be serious: I'm not convinced its either cheaper or easier. If the impactor is nothing but a solid lump of metal with some terminal guidance on board that is going to be a lot cheaper and simpler than
    a robot big enough and smart enough to paint several square kilometers of asteroid surface. Admittedly, the observation probe has to be smarter and so more expensive.

    The impactor could be flimsy drums of titanium oxide powder, with some terminal guidance on board and a self-destruct charge. A few hours before the probe hits the asteroid, ground control detonates the probe and turns it into a big cloud of white dust. This keeps going and hits the asteroid, coating the surface with reflective pigment.

    >:K

  • Re:Typical (Score:3, Insightful)

    by Danse (1026) on Friday August 09, 2002 @12:41PM (#4040567)

    God can kiss my shiny metal ass if he thinks I'm in favor of just letting some rock smash into the planet and kill everything. Besides, if you believe in God, then it works in your favor either way. If the asteroid hits the earth, then it was God's will. If we destroy the asteroid, then it was just God testing us.

  • by Anonymous Coward on Friday August 09, 2002 @12:54PM (#4040678)
    Just because there are other dangers, it doesn't mean we should ignore this one. There is no regular interval for asteroid impacts. It could happen at any time. I'd be rather pissed if NASA listened to dipshits like you and wasn't prepared when there is a real asteroid threat identified.
  • by Ethidium (105493) <chia_tek@yahoDEGASo.com minus painter> on Friday August 09, 2002 @01:06PM (#4040787) Homepage Journal
    The danger is there. The indefinite survival of the species requires dealing with it sometime. Yes, climate change, warfare, disease (AIDS, cancer, et al) are all threats to the survival of our species. So is asteroid impact. We don't know how immediate any of them are, so we had better get planning. Just because something doesn't happen often doesn't mean it won't happen soon.

    500-Year floods happen about once every 500 years, right? Doesn't mean it didn't happen in 1993. "A few times every hundred million years" could mean tomorrow. Sky surveys are great, but they don't have the whole sky covered, nor will they in the near future. To quote a popular space-opera, "it's a big-ass sky."
  • by geoswan (316494) on Friday August 09, 2002 @01:41PM (#4041080) Journal
    ...If all goes to plan, the asteroid's orbit will be disturbed in the beginning by a few fractions of a millimetre...

    I did some of the math for this, on the back of an envelope, when we were this asteroid story from late July [slashdot.org].

    That asteroid was thought to have something like one chance in 300,000 of hitting the Earth in 16 years. I chose 10 years as the amount of time it would take to get something out there to divert it. I assumed it was headed straight at the Earth's center. Then I asked myself how much of a nudge we would have to give the asteroid so it would no longer hit the Earth?

    If an asteroid were headed right towards the Earth, we would have to give ti a big enough nudge to change its target by d-day by something like 5,000 kilometres. That is 5*10^9 millimetres. So if gave an asteroid that was going to hit Earth a nudge of one millimetre per second at right angles to its current trajectory, wouldn't it take at least 5*10^9 seconds to change a direct hit to a near miss?

    There are only 3.1*10^7 seconds in a year.

    So a course change of 1 mm per second will protect us if we have something like 150 years lead time. But adding in a safety margin, and considering they only plan to divert the asteroid fractions of a mm, then that sounds like at least 1000 years.

  • by Anonymous Coward on Friday August 09, 2002 @10:27PM (#4043931)
    Quarry an asteroid, and use large solar powered mass drivers to throw material off the asteroid at very high velocity.

    This would allow you to slow down the asteroid gradually, and with time perhaps put it into earth orbit. (Who said it had to be LEO?)

    Patience might come into play, but I wouldn't mind a 40 year mission to capture an asteroid.

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