Rosetta’s final descent to Comet 67P/C-G

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The Rosetta science team today posted two stories, describing details about the planned final descent of the spacecraft to the surface of Comet 67P/C-G on September 30, ending the mission.

The spacecraft will land in a region dubbed Ma’at that contains several active pits more than 300 feet across and 150 feet deep. This is also where several of the comets dust jets originate.


  • Gealon

    Again I see them going on about how it will be impossible to get any data from the spacecraft after it touches down. And now I’m noting most pointedly in the first link, that they are no longer calling it a landing, but an “impact.” I could take hours to go back to see when this trend started but commenting on the lack of a proper landing attempt is the main reason for my posting and I’d like to stay on point. So the question is, why the “impact?” When Near landed on Eros it too was running out of fuel, but they still managed to make a controlled landing, leaning on it’s solar panels no less.

    Why can’t Rosetta descend in a similar fashion, and land on it’s instrumented side? Literally push them into the soil, and if any survive, keep taking readings. Even if they can’t point the high gain antenna any more, they still have the lower power transmitters. And again even if the solar panels are no longer pointed directly at the sun, the spacecraft has a battery power reserve. USE IT. Fire the RCS jets again a few minutes before expected “impact” to kill the velocity and let it drift down nice and slow. True, it will probably bounce just like Philae did, but at least you’ll make something resembling a controlled landing and who knows, the vehicle might still be functional when it stops. Don’t just crash it into the surface and be done with it. Heck, if they wanted to ensure it doesn’t bounce, it wouldn’t be that hard to feed in another parameter into the programing so that when the vehicle’s IMU’s sense the initial collision, it fire’s it’s jets in a downward direction and hold’s it’s self against the surface. But I’m expecting too much.

    Everything I’m proposing here could be accomplished without jeopardizing ESA’s current plan to Crash Rosetta into the pit. The additions to the programming would take effect only in the last minutes of the descent and given that ESA’s already given up on the craft at that point, and to paraphrase Mr. Trump, What do they have to lose? The probe is already written off after this point anyway. Why not invest a few extra minutes in updating a line of code and see what you can learn from it?

    This to me illustrates the difference between the Near team and the Rosetta team. Near descended and landed in the hope of the craft still functioning after touch down, so that we might learn something from it. Rosetta will be crashed into the comet just so ESA can say, “We did it too.” I’m of the mind that the choice to “land” here is purely political. Nothing can be learned if you intentionally destroy the spacecraft.

  • Gealon

    Update: It appears the reasoning behind the crash/shutdown of Rosetta’s systems is apparent to comply with, you guessed it, government regulations. Not too far off from my supposition that the motivation is political. The probe is evidently being shut down on impact to prevent it from transmitting accidently and interfering with communications channels on the DSN. Frankly this does not change my thinking on the matter.

    If they can instruct the spacecraft to shut it’s self down, they can instruct it to disable it’s transmitter After a computer restart. This would ensure that if Rosetta survives the landing, it could continue to transmit data for as long as it’s batteries permit. Once the batteries die, the computer shut’s down. Then if in the future the solar panels recharge the batteries enough for the computer to restart, it would simply sit there waiting for instructions, NOT using it’s transmitter. This should satisfy everyone from explorers to the government toads that come up with these ridiculous rules, and I’m sure must have been an option proposed. But it’s not being acted upon and this chance to explore the surface of the comet, going boldly to coin a phrase, is instead being turned into nothing more then a stunt. True some information will be acquired during the descent, but what about what could be learned on the surface?

    Link, the answer I’m quoting above is about half way down the page:

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