[meteorite-list] Philae Spacecraft Landed 3 Times on Speeding Comet: See Its First Photos

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 13 Nov 2014 13:06:12 -0800 (PST)
Message-ID: <201411132106.sADL6CFv001360_at_zagami.jpl.nasa.gov>

http://www.space.com/27761-philae-comet-landing-bounces-first-photos.html

Philae Spacecraft Landed 3 Times on Speeding Comet: See Its First Photos
by Miriam Kramer
space.com
November 13, 2014
                             
The European Space Agency's Philae probe landed on the Comet 67P/Churyumov-Gerasimenko
not once or twice, but three times, when its anchor system failed to fire.
But despite that, the probe is healthy and beaming back stunning photos
of its new home.

European Space Agency (ESA) officials still aren't exactly sure where
the Rosetta spacecraft's lander, called Philae, ended up after bouncing
on the surface of Comet 67P/C-G twice before finally settling down. At
the moment, officials think the lander - which was released down to the
comet from the Rosetta orbiter Wednesday (Nov. 12) - is in a potentially
precarious position away from its initial touchdown site. The new comet
surface photos from Philae, released by ESA today, show the lander shadowed
by what appears to be some kind of cliff.

"It's amazing where we are," Jean-Pierre Bibring, Rosetta mission scientist,
said during an ESA news conference today (Nov. 13). "We landed...Please
do not put the emphasis on the failure of the system. It's gorgeous where
we are."

The new photos represent the first-ever pictures taken by a probe from
the surface of a comet. Philae landed on the comet as the icy object,
the lander and Rosetta were speeding across deep space at more than 11,000
mph (17,702 k/h).

Philae's harpoon system, meant to fire just after landing, did not deploy
when Philae got to the comet's surface, and officials with the mission
are not sure if they want to try re-firing them now. Officials are worried
that, if the harpoons don't fire properly, they might cause the spacecraft
to jump again.

Mission controllers now think that Philae could have bounced as far as
1 kilometer (0.6 miles) into space before making its second landing. The
spacecraft then bounced away from the surface again on a shorter jump
before coming to a rest in its current position, officials said today.

Officials are planning on trying to find Philae's spot on the comet's
surface in images its mothership Rosetta took from the comet's orbit.

One of Philae's three landing legs could be off the surface of the comet,
so mission operators are still trying to understand exactly how the lander
is positioned on the comet's surface. ESA officials still aren't sure
whether Philae's drill instrument (designed to investigate the composition
of the comet's surface) will work properly in the lander's current position.

"We are also hesitant to, in the next hour or days, to activate the drill
because drilling without being anchored, and without knowing how you are
[positioned] on the surface, is dangerous," Stephan Ulamec, Philae lander
manager at the DLR German Aerospace Center, said during the news conference.
"We might just tip over our lander."

Scientists also think that the lander is not getting enough sunlight from
its currently shadowed position, and that could reduce the life of the
lander on Comet 67P/C-G's surface. Instead of the 6 to 7 hours of sunlight
expected at the first landing site, Philae is only receiving about 1.5
hours of sunlight on its solar panels in the new spot, ESA officials said.

But scientists working with the mission are still hopeful.

"Even if we think the mission ends because the first science sequence
may end, and the batteries are low, the lander is not necessarily dead,"
Ulamec said. It's possible that the lander could go into hibernation mode
and wake up again when it gets more sunlight, but it's also possible that
might not happen, he added.

The Rosetta spacecraft and Philae lander arrived at Comet 67P/C-G in August
2014 after launching to space in 2004. Rosetta is expected to stay with
the comet, studying it until December 2015.
Received on Thu 13 Nov 2014 04:06:12 PM PST