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C James Fan Club

'Tis the Season, and Fobos-Grunt.

C James

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I found a Christmas tree pic, from Australia!


Posted Image


I'm also reminded, every time I look at the snow outisde, that Australians often celebrate Christmas with a beach picnic. That sure sounds good right now. Posted Image


And, on an utterly unrelated topic, is anyone else following the Fobos-Grunt mission? The names means "Phobos soil" in Russian, and it's a Russian mission to the largest Martian moon, Phobos, intended to bring a half pound of soil back to earth.


Sadly, it won't happen. The probe didn't perform its escape burns after launch in November, and is in low earth orbit. The probe does not respond to commands. The Australians managed to get a ping response and maybe some telemetry frames, but that's it. Even if control is regained, the mission cannot happen; the window for the trans-mars burn is long passed.


Fobos Grunt is quite large, and it holds upwards of 13 tons of highly toxic fuel as well (a type of hydrazine, very nasty stuff). If it freezes, that means some could survive reentry. It becomes very likely it would, if the tanks are titanium instead of aluminum as reported. It'll be widely covered in the press, for sure, starting very soon. The perigee is currently 123 miles (198km), too low for a stable orbit (you get a slight amount of drag at that altitude) so the orbit is decaying. Apogee is curently 169 miles (273KM). The apogee is lowering far more per day then the perigee (due to orbital mechanics, a velocity change on one side of an orbit primarily changes the paramiters of the opposite side, which is why you do a burn at perigee to change apogee, and visa versa). Current re-entry projections center on mid January, and Roscosmos said January 12th, plus or minus 7 days.

Anyone feel like a pick-a-time pool? My own guess is Jan 6th, 4pm GMT, which is a bit earlier than the expert time frames I've seen.


BTW, the one ground station to get any response at all from the spacecraft was an Australian site in Perth. They got a reply ping, plus possible telemetry frames, though that was a couple of weeks ago.

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