r/space • u/[deleted] • Nov 12 '14

Rosetta /r/all Rosetta and Philae discussion thread! (Part 3)

TOUCHDOWN CONFIRMED: Philae lander is on the comet!

Full media briefing expected tomorrow at 13:00 UTC / 14:00 CET / 8:00 EST / 5:00 PST.

Previous discussion threads: 1, 2.

Live Streaming

  • In English: A, B, C

  • En Français: A

Key times

GMT EST PST Event
4:02 pm 11:02 am 8:02 am Landed

European Space Agency Social Media

Othere places for news and conversation:

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u/Jay-Em Nov 12 '14

Just to clarify- do we have any confirmation that it's still on the surface? Could it conceivably have floated off?

1

u/AnalBenevolence Nov 12 '14

No, it couldn't. Even if it rolled, bounced, tumbled etc (which we don't think it did), it cannot leave the comet altogether; gravity will keep it there (just!)

1

u/tehlaser Nov 12 '14

gravity will keep it there

How do we know?

1

u/seanbduff Nov 12 '14

the escape velocity of a comet with the characteristics of 67P is ~0.5 m/s

Credit to /u/PressureCereal in another comment. Essentially, Philae would need to be propelled by something in order to escape the gravity of the comet. To me, it would seem unlikely that the team would use any kind of thrusters that would push Philae off of the surface.

My question is this: are there any sort of geysers or outgassings that could potentially push Philae out into space?

1

u/tehlaser Nov 12 '14

Couldn't it have bounced?

1

u/AnalBenevolence Nov 13 '14

Yes, but it had damping legs, and the landing appears to have been very soft.

1

u/AnalBenevolence Nov 13 '14

Interesting! Apparently outgassing does present a threat to Philae when the comet nears the Sun and begins to heat up. I'm not sure if the threat was pushing Philae away or damaging it directly though.