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Space Science

Rosetta, the Comet Hunter 132

Roland Piquepaille writes: "After being delayed for about a year because of a failure of the Ariane-5 rocket, the Rosetta spacecraft is scheduled to be launched on February 26. Rosetta is a special spacecraft, including an orbiter and a lander. And it will take up to 2014 before landing on Comet 67P/Churyumov-Gerasimenko -- with the help of a harpoon. Then, as says the European Space Agency (ESA), Rosetta will help to solve planetary mysteries. This news release looks at the goals of Rosetta's mission and explains why it will take more than ten years to reach the comet. But here the 'funny' part of the story: the landing. 'In November 2014, the lander will be ejected from the spacecraft from a height which could be as low as one kilometre. Touchdown will be at walking speed, about one metre per second. Immediately after touchdown, the lander will fire a harpoon into the ground to avoid bouncing off the surface back into space, since the comet's extremely weak gravity alone would not hold onto the lander.' This overview contains more details and includes illustrations of the Rosetta's spacecraft and its landing on the comet."
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Rosetta, the Comet Hunter

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  • Gravity? (Score:5, Interesting)

    by Moderator ( 189749 ) * on Saturday January 31, 2004 @07:10PM (#8146618)
    The timeline states that in 2014, Rosetta will orbit the comet for six months before it lands, mapping the comet to find a suitable landing spot. Then it goes on to say:
    Immediately after touchdown, the lander will fire a harpoon into the ground to avoid bouncing off the surface back into space, since the comet's extremely weak gravity alone would not hold onto the lander..

    My question is, if the comet's gravity is so weak, how is the Rosetta supposed to orbit this thing for six months?
  • by bc90021 ( 43730 ) * <`bc90021' `at' `bc90021.net'> on Saturday January 31, 2004 @07:11PM (#8146626) Homepage
    ...given that we probably know little about the surface of the comet.

    Given that it could be porous (or even lots of shatterable ice), I hope that the harpoon has the force to bury itself deeply enough to actually anchor itself in something solid.
  • by questamor ( 653018 ) on Saturday January 31, 2004 @07:16PM (#8146657)
    I'm curious. How big does an object have to be to have gravity that'll hold say, a person to it?

    I'm thinking say, if I were standing on a rock the size of NYC out in space, would I just drift away from its surface without any noticeable gravity, or could it hold me there? How about something the size of a state like Oregon? or something only 2miles in diameter?
  • by fname ( 199759 ) on Saturday January 31, 2004 @07:25PM (#8146701) Journal
    The French had a very reliable launch vehicle, the Arianne IV, which they decided to "upgrade" with the Arianne V. After failing on 4 of the first 13 missions, they introduced an upgraded version with an extended nozzle. The failure of that launch led to the (highly justified) delay of the Rosetta launch on a similar Arianne V because of the failure investigation. Turns out that the nozzle had a design flaw which led to the failure.

    ESA did pretty well on their 1st trip to Mars, as the Mars Express is an unqualified success, but the Beagle II didn't work for whatever reason. All this is just to reiterate that space is hard, and there will be successes and failures. No one's at 100% (Russians have a worse track record on Mars than anyone, and NASA lost Contour--not a JPL mission-- last year due to an obvious design flaw).

    Whenever a new technique is tried in space for the 1st time, the odds increase. That Pathfinder worked on its first attempt at a bouncy landing, and Sojourner roved Mars without a hitch speaks to the talent & luck of the JPL crew. Hopefully the Europeans will do as well with their harpoon, and hopefully they haven't made obvious mistakes like those made by NASA and the APL did in the Contour comet mission.
  • Comment removed (Score:3, Interesting)

    by account_deleted ( 4530225 ) on Saturday January 31, 2004 @08:34PM (#8147037)
    Comment removed based on user account deletion
  • by Uncle Barnard's Star ( 714324 ) on Saturday January 31, 2004 @08:45PM (#8147111)
    The cool factor is undoubtedly high, kind of like catching a speeding racing car to find out what's under the hood. The risks are high, and the payoff is worth its weight in journal articles. Maybe it's time for missions that try to justify thier cost in kind.

    The so-called great voyages of discovery of the past were never undertaken for the sake of idle science all. Always there was that search for the elusive El Dorado or that secret shortcut to the spice capital of the world. While most voyages failed to recoup the wood and slave labor invested on them, enough returned with if not the silver and gold then things that would prove more valuable, like coffee, cannabis or the claims to a "New" World.

    The pure science mission ("Is there life on Mars?") is a modern invention. While the altruism is admirable, the only way to justify to taxpayers the continued exploration of space is to turn these missions into hunts for precious metals and minerals. Follow not just the water (a valuable space resource in its own right) but also the platinum.

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