[meteorite-list] Rosetta Sets Sights on Destination Comet (67P/Churyumov-Gerasimenko)

[Ron Baalke]

http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_sets_sights_on_destination_comet

Rosetta Sets Sights on Destination Comet
European Space Agency
27 March 2014

[Images]

ESA's Rosetta spacecraft has caught a first glimpse of its destination 
comet since waking up from deep-space hibernation on 20 January.

These two "first light" images were taken on 20 and 21 March by the OSIRIS 
wide-angle camera and narrow-angle camera, as part of six weeks of activities 
dedicated to preparing the spacecraft's science instruments for close-up 
study of comet 67P/Churyumov-Gerasimenko.

OSIRIS, the Optical, Spectroscopic and Infrared Remote Imaging System, 
developed under the leadership of the Max-Planck-Institut fur Sonnensystemforschung 
in Gottingen, Germany, has two cameras for imaging the comet. One covers 
a wide angle, while the narrow-angle camera covers a smaller field at 
higher resolution.

[Image]                                                               
             
Rosetta's first sighting of its target in 2014 - wide angle view

OSIRIS is one of a suite of 11 science instruments on the Rosetta orbiter 
that together will provide details on the comet's surface geology, its 
gravity, mass, shape and internal structure, its gaseous, dust-laden atmosphere 
and its plasma environment.

Rosetta has been travelling through the Solar System for 10 years, and 
will finally arrive at the comet in August this year. It first imaged 
the comet in a long exposure of over 13 hours from a distance of 163 million 
kilometres, three years ago, before entering deep-space hibernation.

Rosetta is currently around 5 million kilometres from the comet, and at 
this distance it is still too far away to resolve - its light is seen 
in less than a pixel and required a series of 60-300 second exposures 
taken with the wide-angle and narrow-angle camera. The data then travelled 
37 minutes through space to reach Earth, with the download taking about 
an hour per image.

"Finally seeing our target after a 10 year journey through space is an 
incredible feeling," says OSIRIS Principal Investigator Holger Sierks 
from the Max Planck Institute for Solar System Research in Germany. "These 
first images taken from such a huge distance show us that OSIRIS is ready 
for the upcoming adventure."

"This is a great start to our instrument commissioning period and we are 
looking forward to having all 11 instruments plus lander Philae back online 
and ready for arriving at the comet in just a few month's time," says 
Matt Taylor, ESA's Rosetta project scientist.

OSIRIS and the spacecraft's dedicated navigation cameras will regularly 
acquire images over the coming weeks to help refine Rosetta's trajectory 
in order to bring it steadily in line with the comet ahead of the rendezvous.

Currently, Rosetta is on a trajectory that would, if unchanged, take it 
past the comet at a distance of approximately 50 000 km and at a relative 
speed of 800 m/s. A critical series of manoeuvres beginning in May will 
gradually reduce Rosetta's velocity relative to the comet to just 1 m/s 
and bring it to within 100 km by the first week of August.

Between May and August the 4 km-wide comet will gradually "grow" in Rosetta's 
field of view from appearing to have a diameter of less than one camera 
pixel to well over 2000 pixels - equivalent to a resolution of around 
2 m per pixel - allowing the first surface features to be resolved.

These early observations will allow the rotation rate and the shape of 
the nucleus to be better understood, crucial for planning manoeuvres around 
the comet. An initial assessment of the comet's activity will also be 
possible.

With OSIRIS re-activated in the first week of instrument commissioning, 
Rosetta's 10 other science experiments, along with lander Philae, will 
provide the focus for the next months' activities.

For an overview of the instrument commissioning schedule, and for regular 
status reports, visit the Rosetta blog.

More about Rosetta

Rosetta is an ESA mission with contributions from its member states and 
NASA. Rosetta's Philae lander is provided by a consortium led by DLR, 
MPS, CNES and ASI. Rosetta will be the first mission in history to rendezvous 
with a comet, escort it as it orbits the Sun, and deploy a lander to its 
surface. Comets are time capsules containing primitive material left over 
from the epoch when the Sun and its planets formed. By studying the gas, 
dust, structure of the nucleus and organic materials associated with the 
comet, via both remote and in-situ observations, the Rosetta mission should 
become the key to unlocking the history and evolution of our Solar System, 
as well as answering questions regarding the origin of Earth's water and 
perhaps even life.

More about OSIRIS

The scientific imaging system OSIRIS was built by a consortium led by 
the Max Planck Institute for Solar System Research (Germany) in collaboration 
with CISAS, University of Padova (Italy), the Laboratoire d'Astrophysique 
de Marseille (France), the Instituto de Astrofisica de Andalucia, CSIC 
(Spain), the Research and Scientific Support Department of the European 
Space Agency (The Netherlands), the Instituto Nacional de Tecnica Aeroespacial 
(Spain), the Universidad Politehnica de Madrid (Spain), the Department 
of Physics and Astronomy of Uppsala University (Sweden), and the Institute 
of Computer and Network Engineering of the TU Braunschweig (Germany).

 
For further information, please contact:

Markus Bauer
ESA Science and Robotic Exploration Communication Officer
Tel: +31 71 565 6799
Mob: +31 61 594 3 954
Email: markus.bauer at esa.int

Fred Jansen
ESA Rosetta mission manager
Email: fjansen at rssd.esa.int

Matt Taylor
ESA Rosetta project scientist
Email: matthew.taylor at esa.int

Holger Sierks
OSIRIS Principal Investigator
Email: Sierks at mps.mpg.de