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China Plans Deep Impact Mission

Posted by Zonk on from the sequels-are-great dept.

Comatose51 writes "China is planning its own Deep Impact mission. The goal of the mission, unlike the exploratory NASA project, is to push potential life-ending comets or asteroids away from a collision course with the earth." From the article: " The third nation to launch a man into space has lofty space ambitions that include putting two astronauts into orbit this September and eventually sending up a space station and even a manned mission to the moon."

2 of 286 comments (clear)

  1. The math doesn't look good... by G4from128k · · Score: 4, Interesting

    An estimate of the orbital delta-v for Tempel /Deep Impact suggests a velocity change of only 1 cm/hour (I can't vouch for the math). Assuming we would need to nudge a threatening body by 1/2 the diameter of the Earth (from direct hit to grazing pass-by), we would need to know to hit a Tempel 1-sized body in advance by over 73,000 years. This type of mission would work 10 years in advance for much smaller bodies (say less than 350 m in diameter). Even these estimates assume a perfect strike by the deflecting deep impactor -- a margin of error or the need to push the object several Earth-diameters further reduces the potential for this method.

    Kinetic energy is not the way to go. Deep Impact delivered only about 4.5 kt of TNT. In contrast, a good sized thermonuclear weapon could deliver thousands of times that energy (even taking into account the relatively poor conversion of 100 megatons yield into delta-V).

    --
    Two wrongs don't make a right, but three lefts do.
    1. Re:The math doesn't look good... by iggymanz · · Score: 3, Interesting

      Here's neat link mentioning megatons of yield needed to deflect 1km asteroid by cm/s. here Repeated applications of the more usual 1-5 MT warheads seems more reasonable than the need to invent a 100MT monster. But if the dimensions of the asteroid are of the order of dozens of cubic km then we're probably screwed! 8D

      Just to wax philosophical for a moment, I hear people talk about founding space stations so we "don't have all our eggs in one basket", but if the entire earth gets wiped out does it really matter if we have a couple dozen people in a space station or moon base? nah, who gives a crap at that point, certainly you or I won't....