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The Rosetta Mission

The New York Times has a good article today on the European Space Agency's Rosetta mission, which sounds like the most complex robotic space mission ever attempted:

The 8,000-pound robotic spacecraft is to be launched on Thursday by the European Space Agency from Kourou, French Guiana, on the northeastern coast of South America, by Europe's most powerful rocket, the Ariane 5.

Two hours after the spacecraft enters Earth orbit, an upper stage will send the Rosetta off on a roundabout decade-long journey through the solar system on a mission to find and chase Comet 67P/Churyumov-Gerasimenko.

The Rosetta will have to travel hundreds of millions of miles on a path that requires four planetary flybys to build momentum and eventually sling it to a point 420 million miles from the Sun for a rendezvous with the small incoming comet, around May 2014.

By August 2014, the spacecraft is to go into an orbit 15 miles from the nucleus of the two-and-a-half-mile-wide comet. Three months later -- after surveying the chunk of ice, dust and other debris for suitable sites -- the Rosetta will move within a couple of miles of the surface and release a 270-pound craft, Philae, that will try to make the first landing on a comet.

Because the comet is so small and its gravity extremely weak, the lander has to drift down and touch the surface at a speed of no more than three feet a second or it could bounce away, researchers said. To hold it down, Philae's three legs have special shock absorbers to cushion its touch. Each is fitted with ice pitons that quickly bore into the surface. The lander will immediately fire a harpoon into the ground to anchor it...

Scientists will use a suite of 21 instruments, some never flown on a deep-space mission. The instruments, 11 on the orbiter and 10 on the lander, will seek to measure the comet's composition, age, temperatures, interaction with solar radiation and other characteristics as it approaches the Sun.

The article mentions the expected $1.25 billion cost of Rosetta. According to New Scientist, a manned mission to Mars is expected to cost $40-80 billion. I, for one, would rather have 32-64 Rosetta-class missions rather than one mission to Mars.

Mark your calendars for May 2014, when Rosetta will first arrive at the comet. (The lander won't be released for another six months.)


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If all 32 remote missions worked, it would probably be worth it, but lots of things go wrong, and those tiny little on-board computers can't really deal with much outside their narrow mission profile. Just take a look at how many remote missions we've smeared across the face of mars. So if the choice is one manned mission to mars, or 6-10 successful remote missions (out of 32-?), then I'll take the manned mission.

Personally, I don't see it as an either or. Continue the un-manned missions, while using the knowledge and technological advances to make a manned mission more practical.

Assuming a manned Mars mission cost of $40 billion, and a Rosetta-class mission cost of $1.25 billion, or 32 Rosettas for one manned mission to Mars, your range of 6-10 successful missions represents a success rate of 18.8-31.3 percent. Assuming a manned Mars mission cost of $80 billion, your numbers imply a success rate of 9.4-15.6 percent. Do you stand behind those numbers?

I don't have the research in front of me, but I'm fairly sure that our success rate on deep space missions is greater than you're implying here.

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