Donât forget xkcdâs live-comic of the event.
Landing on a Comet Achievement Unlocked !! 
TL;DW:
Landed!
I love that my first real confirmation that it was down was the (lead engineer? flight manager?) happily saying âcazzoâ (âpenisâ, or âfuckâ in Italian) while everyone was cheering.
There is a dedicated website where you can page through all of the updates as the lander approached.
Mazel tov humans!
Congratulations ESA!!! This has been so amazing to watch unfold. Anybody know when/if the lander will be sending back hi-res video and photos?
Congratulations to ESA and the Rosetta Team! The freakin live feed cut out on me just as the lander was known to have set down on the comet, so I learned of the success via XKCD, which is actually okay with me.
Aaaaand cue the âEarth-Firstersâ chiming in with tweets along the lines of âHey thatâs great and all but did ESA end [world hunger/war/genocide/etc]?â Where are these folks when their governments spend shitloads of cash on weaponry, or collude with banks, or make art?
EDIT: For your reading pleasure:
We can achieve a #CometLanding, but can't have smooth roads in #Michigan.
Seeing some suggestions that itâs landed, but they arenât sure how secure it is. Harpoons didnât fire?
Still - awesome stuff.
But has it been done in another history, that isnât âthe history of mankind.â?
Yeah, looks like the harpoons didnât fire, so Philae isnât secured to the comet. They could try to fire them again, but, if they donât grab, the force will knock Philae off the comet. Talk about a tough decision for mission control.
Apparently, there are a couple of drilling experiments that require Philae to be securely held down. The experiments could push the craft off the comet.
From ESAâs briefing by the Philae manager, Stefan:
What we know:
- Philae landed at the comet (thus the cheering)
- Received data (housekeeping and science)
- Anchoring harpoons did not fire. Philae is not anchored. (Why?)
- Irregular fluctuations in the radio link, but still a good link for good data. (Why?)
- Fluctuations also in the solar generator. (Why?)
- 2 hours later, fluctuations stopped.
Speculations: Philae may have bounced. Could be that it rotated while bouncing (would account for the fluctuations). Maybe not.
Current status:
Radio link is severed. This is normal because Philae is over 67Pâs horizon. It has been instructed to perform some of its science while we wait for the radio link to come up tomorrow morning (UTC).
Which is when weâll know more.
[edit: sorry, the media briefing will be at 1400 CET (0800 EST) tomorrow, the 13]
How much delta-v do they have remaining?
We donât know. In fact, we know very little. Earlier reports (during the Go/No Go decision or shortly after separation) suggested that the dohicky with a TLA or FLLA for a name on top of Philae that was supposed to generate the necessary force to keep it from bouncing off when the harpoons fired didnât/couldnât fire. Not sure if thatâll change.
I eagrely await the near future where space missions spit out realtime data feeds in parallel with realtime reporting. Then people who know how to read telemetry data can build visualizations and concoct speculations and explanations and⌠Oh man, wouldnât it be wonderful? Itâd be like xkcdâs live comic-blog, but actually live (minus transmission delay and buffering)
But then weâd also know how much the ESA doesnât know. Some people are going to be wondering how they couldnât know how many times Philae landed, or whether it rotated. Theyâve spent millions on it, how could they not know exactly where it is and which way itâs pointing (+28mins lag)?!
Iâd guess that any physicist would tell you that the landing has already happened trillions of times in alternate/parallel universesâŚ
Iâd like to know how that worksâare the harpoons and theâŚuhâŚalternate-force-jet thing on top (meant to offset the harpoon firing) triggered by sensors on the arms that indicate Philae is level, with respect to the surface, or did the harpoon not fire because of some fault in its own mechanics (broken valve, busted flux capacitor, etc.)? I wish theyâd put up a fault chart, or some schematic that would show specifics as to how the lander was meant to operate.
Also, I believe Iâve read that the rotational period of the comet is around 12 hours, but that Rosetta wonât achieve proper orbit around the comet again until 12/6. I wonder if or when Rosetta will be able to photograph the lander to help determine whatâs going on?
Really, the whole damn thing is phenomenal. Between the multiple gravity boosts and the orbiting of a snowball many millions of kilometers awayâPhilae was really the mechanical cherry on top.
EDIT: Due to browsing XKCD after the main event, I found the âDictionary of Numbersâ extension for Chrome, which adds relevance to large numbers notated in web pages. For instance, Rosetta has been orbiting 67P at about 10km, which altered ESAâs blog to tell me that,
Following a period spent at 10 km [â depth of deepest part of the ocean, Mariana Trench] to allow further close-up study...Highly recommended.
None (if iâm understanding your question). Philae is unpowered â essentially, Rosetta just dropped it, relying on good aim and the oh-so-slight gravity of the comet to land it. First touchdown was at 15:33UTCâŚand it (apparently) bounced. Second touchdown was at 17:26âŚand it bounced again. The second bounce lasted only 7 minutes, and Philaeâs third touchdown occurred at 17:33.
They were saying something about a small jet to counteract the delta-v from the harpoons. Thatâs what I meant, primarily.
Just seen on the twitters:
