It's ALIVE! Broken Russian Mars probe finally answers calls The Martian probe Phobos-Grunt, lost in space for the last 14 days, has finally responded to Earth's signals. The European Space Agency said on its website today that its tracking station in Perth, Australia, had received a signal from the craft at 2025 GMT on Tuesday. "ESA teams are working closely with engineers in Russia …
You can't keep a satellite up without expending power, even Geosync satellites need a little power for station keeping, in a low earth orbit you have atmospheric drag to contend with, let alone avoiding all the bits and bobs that are spinning around up there. Send it to the moon, get some sort of work out of it, although I bet that's going to be tricky as the moon has a higher G than phobos.
Well, why not send it to the moon and use a gravitational slingshot to whip it towards Mars? Would that not be worth a shot? That said, perhaps they've been planning that all along. And I suppose it's not just the getting-going that's the issue - the thing has to stop at the other end too.
Still, could be cool if it worked - like MacGuyver in space!
"Possibly not as NASA is launching a Mars mission on Saturday"
yes, but are they launching into the same orbit as the Russian probe? If not, you need a different thrust vector. Also Curiosity is actually going to Mars, whereas the Russian mission is (was) to Phobos.
SImilarly, perhaps it could be boosted to a higher orbit and hibernate for a couple of years, but again it would then need a different thrust vector, and perhaps would not have enough fuel on board to do that.
Phobos-Grunt was intended to land on Phobos and then launch back to Earth again - so it needs to carry enough fuel to wander all the way back to Earth again. Curiosity is only going one way, so needs half as much fuel (for argument's sake, I doubt the planned routes to and from Phobos are identical) - so NASA can afford to go on the slightly more "expensive" route by making their fuel tanks a little bit bigger.
This wiki article gives a fairly good overview of how much "Delta-v" is used for certain transfers: http://en.wikipedia.org/wiki/Delta-v_budget
Interestingly, according to that page, orbit-keeping is fairly cheap (25-100m/s a year) versus the minimum 12,400m/s to Phobos and back. Assuming a couple of percent spare fuel on board, it might actually be possible to wait til the next window, on a fuel basis alone.
The most efficient, i.e. minimum-energy Hohmann transfer orbit launch windows for Mars occur about every 780 days and are open for about a month. The closer you are to the ideal launch date the less energy (fuel) you require and the biggest supplier of that energy is the launch vehicle. So although the NASA launch is after the Grunt launch the launch vehicles are different and this may be a factor.
Phobos-Grunt was launched from Baikonur at a latitude of 46 degrees whereas the 'merkin launch is from Cape Canaveral at a latitude of 28 digress, which confers an advantage on launches from Cape Canaveral as it is nearer to the equator and gets a bigger assist from the spin of the earth enabling a launch from Cape Canaveral to either achieve a bigger range of orbits or to launch a heavier satellite.
"Thank you for calling the Phobos-Grunt probe. Your call is important to us. We now have four options for you:
To go to Mars press 1 ... to go to the Moon press 2 ... to de-orbit press 3 ... to hear a duck quack please press 9."
It's got the Haynes "Interplanetary probes" manual in a pocket.
This whole fiasco reminds me of the story of the Russian's when they sent a probe up to the moon I think it was. It landed and immediately lost contact, all the techies knew someone was going to get sent off to the Gulags for the severe cock-up. One of the techs said, "I think we've landed in something!" to which the manager in charge said, "Yes, the shit!".
I wonder if there is an off chance that this probe can be repurposed to go as far as Jupiter to get a sample of some sort from Europa.
It seems that sending the probe to the Moon is probably going to result in what in the post-Apollo era would be an unremarkable core sample. Landing on the interesting parts of the moon would probably take a lot more mission planning than the Russians have time for and maybe a differently designed lander that is obviously not possible at this time.
I'd rather take a small chance at getting something back that could be really enlightening, rather than get another sample of lunar basalt or brecchia.
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