[meteorite-list] Pioneering Philae Completes Main Misson Before Hibernation

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 17 Nov 2014 16:01:28 -0800 (PST)
Message-ID: <201411180001.sAI01Sj8023882_at_zagami.jpl.nasa.gov>

http://www.esa.int/Our_Activities/Space_Science/Rosetta/Pioneering_Philae_completes_main_mission_before_hibernation
 
Pioneering Philae completes main mission before hibernation
European Space Agency
15 November 2014

Rosetta's lander has completed its primary science mission after
nearly 57 hours on Comet 67P/Churyumov-Gerasimenko.

After being out of communication visibility with the lander since
09:58 GMT / 10:58 CET on Friday, Rosetta regained contact with
Philae at 22:19 GMT /23:19 CET last night. The signal was
initially intermittent, but quickly stabilised and remained very
good until 00:36 GMT / 01:36 CET this morning.

In that time, the lander returned all of its housekeeping data, as
well as science data from the targeted instruments, including
ROLIS, COSAC, Ptolemy, SD2 and CONSERT. This completed the
measurements planned for the final block of experiments on the
surface.

<http://www.esa.int/ESA_Multimedia/Images/2014/11/First_comet_panoramic>

First comet panoramic

In addition, the lander's body was lifted by about 4 cm and
rotated about 35 degrees in an attempt to receive more solar energy. But
as the last science data fed back to Earth, Philae's power rapidly
depleted.

"It has been a huge success, the whole team is delighted,' said
Stephan Ulamec, lander manager at the DLR German Aerospace Agency,
who monitored Philae's progress from ESA's Space Operations Centre
in Darmstadt, Germany, this week.

"Despite the unplanned series of three touchdowns, all of our
instruments could be operated and now it's time to see what we've
got."

Against the odds - with no downwards thruster and with the
automated harpoon system not having worked - Philae bounced twice
after its first touchdown on the comet, coming to rest in the
shadow of a cliff on Wednesday 12 November at 17:32 GMT (comet
time - it takes over 28 minutes for the signal to reach Earth, via
Rosetta).

The search for Philae's final landing site continues, with
high-resolution images from the orbiter being closely scrutinised.
Meanwhile, the lander has returned unprecedented images of its
surroundings.

While descent images show that the surface of the comet is covered
by dust and debris ranging from millimetre to metre sizes,
panoramic images show layered walls of harder-looking material.
The science teams are now studying their data to see if they have
sampled any of this material with Philae's drill

"We still hope that at a later stage of the mission, perhaps when
we are nearer to the Sun, that we might have enough solar
illumination to wake up the lander and re-establish communication,"
added Stephan.

>From now on, no contact will be possible unless sufficient
sunlight falls on the solar panels to generate enough power to
wake it up. The possibility that this may happen later in the
mission was boosted when mission controllers sent commands to
rotate the lander's main body with its fixed solar panels. This
should have exposed more panel area to sunlight.

The next possible communication slot begins on 15 November at
about 10:00 GMT / 11:00 CET. The orbiter will listen for a signal,
and will continue doing so each time its orbit brings it into
line-of-sight visibility with Philae. However, given the low
recharge current coming from the solar panels at this time, it is
unlikely that contact will be re-established with the lander in
the near future.

Meanwhile, the Rosetta orbiter has been moving back into a 30 km
orbit around the comet.

It will return to a 20 km orbit on 6 December and continue its
mission to study the body in great detail as the comet becomes
more active, en route to its closest encounter with the Sun on 13
August next year.

Over the coming months, Rosetta will start to fly in more distant
"unbound' orbits, while performing a series of daring flybys past
the comet, some within just 8 km of its centre.

Data collected by the orbiter will allow scientists to watch the
short- and long-term changes that take place on the comet, helping
to answer some of the biggest and most important questions
regarding the history of our Solar System. How did it form and
evolve? How do comets work? What role did comets play in the
evolution of the planets, of water on the Earth, and perhaps even
of life on our home world.

"The data collected by Philae and Rosetta is set to make this
mission a game-changer in cometary science," says Matt Taylor,
ESA's Rosetta project scientist.

Fred Jansen, ESA's Rosetta mission manager, says, "At the end of
this amazing rollercoaster week, we look back on a successful
first-ever soft-landing on a comet. This was a truly historic
moment for ESA and its partners. We now look forward to many more
months of exciting Rosetta science and possibly a return of Philae
from hibernation at some point in time."
Received on Mon 17 Nov 2014 07:01:28 PM PST