Mars is a Harsh Mistress

Yesterday, November 21, the window for Russia’s Phobos-Grunt probe to leave Earth on a sample return mission to Mars officially closed with the spacecraft still in Earth orbit. Phobos-Grunt was, in my mind, one of the flagship missions of the decade (along with Juno, MSL, and New Horizons). It will be a long time now until we see a major sample-return mission of that scale. Fortunately, some creative-minded people are thinking up ways to get Phobos-Grunt to other destinations. Those ideas are of course based on the assumption that the spacecraft will ever be recovered at all.

As a member of the Planetary Society I was particularly excited about the LIFE project. For LIFE the destination is not important and some near-earth-object could do just as well. So I hope very much that the engineers over in Russia keep trying as long as funding is available to salvage the mission they worked so hard to launch.

Interestingly, there is talk today, via Universe Today, that Phobos-Grunt still has a window to go to Mars on a one-way trip for another few weeks. This probably implies that they would use up much of their return fuel to send Phobos-Grunt on a faster trajectory, making up for the delayed departure. This poses an interesting cost-benefit analysis for the mission managers, if by some providence the spacecraft is recovered before the one-way-trip departure window closes.

The mission objectives of Phobos-Grunt were largely based on the sample return architecture that took a lot of time and money to incorporate. If you send the mission to Mars without planning to return, you are forsaking all of that hard work. It would have been a much cheaper mission if it had not been designed with sample return in mind. So then what do you do? Do you save the Mars destination and deliver China’s Yinghou-1 orbiter to Martian orbit or do you save the mission objectives and find some enticing NEO to sample?

These are the types of tough decisions mission managers in our business often have to make, because most things don’t go as planned. Similar arguments over mission priorities happen in the ISS program all the time, although often without quite so much on the line.

Speaking of a lot on the line, the Mars Science Laboratory will be launching this Saturday, November 26. Hopefully MSL will head off to Mars without a hitch. I’d hate to have to revise this graphic with two more Mars mission failures.

via Gizmodo


November 22, 2011 6:15 pm

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