Reconstructing Philae’s flight
One year given Philae done a ancestral alighting on a comet, goal teams sojourn carefree for renewed hit with a lander, while also looking forward to subsequent year’s grand finale: creation a tranquil impact of a Rosetta orbiter on a comet.
Rosetta arrived during Comet 67P/Churyumov–Gerasimenko on 6 Aug 2014, and after an initial consult and preference of a alighting site, Philae was delivered to a aspect on 12 November.
After touching down in a Agilkia segment as planned, Philae did not secure itself to a comet, and it bounced to a new plcae in Abydos. Its moody opposite a aspect is decorated in a new animation, regulating information collected by Rosetta and Philae to refurbish a lander’s revolution and attitude.
In a year given landing, a consummate research has also now been achieved on because Philae bounced.
There were 3 methods to secure it after landing: ice screws, harpoons and a tiny thruster. The ice screws were designed with comparatively soothing element in mind, though Agilkia incited out to be really tough and they did not dig a surface.
The harpoons were able of operative in both softer and harder material. They were ostensible to glow on hit and close Philae to a surface, while a thruster on tip of a lander was meant to pull it down to negate a boomerang from a harpoon.
Attempts to arm a thruster a night before failed: it is suspicion that a sign did not open, nonetheless a sensor disaster can't be excluded.
Then, on landing, a harpoons themselves did not fire. “It seems that a problem was possibly with a 4 ‘bridge wires’ holding stream to light a bomb that triggers a harpoons, or a bomb itself, that competence have degraded over time,” explains Stephan Ulamec, Philae lander manager during a DLR German Aerospace Center.
“In any case, if we can recover hit with Philae, we competence cruise an try to retry a firing.”
The reason is scientific: a harpoons enclose sensors that could magnitude a heat next a surface.
Despite a random bouncing, Philae finished 80% of a designed initial scholarship method before descending into hibernation in a early hours of 15 Nov when a primary battery was exhausted. There was not adequate object in Philae’s final plcae during Abydos to assign a delegate batteries and continue scholarship measurements.
The wish was that as a comet changed nearer to a Sun, streamer towards closest proceed in August, there would be adequate appetite to reactivate Philae. Indeed, hit was done with a lander on 13 Jun though usually 8 few contacts were done adult to 9 July.
The problem was that a augmenting object also led to increasing activity on a comet, forcing Rosetta to shelter to several hundred kilometres for safety, good out of operation with Philae.
However, over a past few weeks, with a comet’s activity now subsiding, Rosetta has started to proceed again. This week it reached 200 km, a extent for creation good hit with Philae, and currently it dips to within 170 km.