Philae landing on the nucleus of Comet 67P C-G |
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Philae landing on the nucleus of Comet 67P C-G |
 Nov 12 2014, 08:06 AM
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#121
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Senior Member  Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780  |
This has been considered.
Since the surface probably isn't as hard as ice, but soft as somewhere between settled snow and cigarette ash, the landing gear will sink into the surface. It's unlikely, that the trajectory will be perfectly perpendicular to the surface. That way it's plausible, that some temporary fixation, or at least considerable dampening, should be possible even without thrust. For long enough, hopefully, for the other mechanisms to work. We'll know more in about eight hours. |
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Nov 12 2014, 08:08 AM
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#122
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 Member Group: Members Posts: 105 Joined: 13-July 05 From: The Hague, NL Member No.: 434 |
Hopefully the softness of the comet surface at the landing spot will mitigate part of the bouncing-off risk, in combination with the overall low speed of approach (walking pace). If I recall the surface strenght is now estimated in the lower range of the 2kPa – 2 Mpa design range for the landing system.
The next critical thing is that the screws needed to impart the targeted slow departure speed of Philea will work fine! |
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Nov 12 2014, 09:04 AM
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#123
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
relaxed faces in the control room
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Nov 12 2014, 09:10 AM
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#124
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 Senior Member Group: Members Posts: 2091 Joined: 13-February 10 From: Ontario Member No.: 5221 |
Separation confirmed!
Time to catch a few zzzs here on PST. |
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Nov 12 2014, 09:19 AM
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#125
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Junior Member Group: Members Posts: 70 Joined: 12-November 06 Member No.: 1354 |
About 100 minutes to AOS for both lander and orbiter. Who needs sleep!
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Nov 12 2014, 11:07 AM
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#126
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
applause!
Just receiving regular telemetry data from the lander. |
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Nov 12 2014, 11:07 AM
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#127
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Junior Member Group: Members Posts: 70 Joined: 12-November 06 Member No.: 1354 |
Yes, Yes, Yes!!! AOS!
Confirm telemetry on lander! |
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Nov 12 2014, 11:07 AM
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#128
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 IMG to PNG GOD Group: Moderator Posts: 2251 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
One thing I just remembered regarding possible bouncing off the surface etc.: This is not the first attempted landing on an extremely low gravity body. NEAR and Hayabusa both successfully landed on small bodies (but the comet's surface properties are probably very different from Eros' and Itokawa's). Fingers crossed...
EDIT: AOS!!!!!!!!!!!!! |
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Nov 12 2014, 11:08 AM
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#129
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Member Group: Members Posts: 107 Joined: 1-August 14 Member No.: 7227 |
AOS confirmed.
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Nov 12 2014, 11:13 AM
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#130
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Junior Member Group: Members Posts: 70 Joined: 12-November 06 Member No.: 1354 |
Next up, data dump from both spacecraft in the next two hours. (possibly including navcam photos)
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Nov 12 2014, 11:26 AM
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#131
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 Senior Member Group: Members Posts: 2173 Joined: 28-December 04 From: Florida, USA Member No.: 132 |
QUOTE (Bjorn Jonsson @ Nov 12 2014, 06:07 AM)  One thing I just remembered regarding possible bouncing off the surface... It's interesting to see how the discussion over the last few days has switched from fears of sinking to concern of bouncing off the comet! My own concern has been how the ice screws in the feet will work on the surface which, whatever it is, appears not to be ice. Just a few more hours.... all will be revealed.
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Nov 12 2014, 11:27 AM
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#132
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
Telemetry update:
- flywheel operating, - landing gear deployed. |
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Nov 12 2014, 12:44 PM
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#133
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Junior Member Group: Members Posts: 70 Joined: 12-November 06 Member No.: 1354 |
ESA sez:
QUOTE Next live 14:00 GMT / 15:00 CET Live ESA TV report on first science data coming from Philae during descent. Touch down expected 16:02 GMT / 17:02 CET. Should include first photos. |
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Nov 12 2014, 01:20 PM
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#134
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 Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Per DSN Now, downlink from Rosetta apparently in progress through DSN 55. That antenna is almost parallel to the ground, pointing right at the horizon!
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Nov 12 2014, 01:30 PM
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#135
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
"We've started to receive science data".
CIVA shows, that separation ok. "We've all data, we've hoping for". "Everything is coming as expected". "At 15h CET, we've a lot more to show you". |
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