ESA Rosetta’s Comet Landing Site J Close Up

An annotated mosaic from the Rosetta spacecraft shows “Site J,” the primary landing site on comet 67P/Churyumov–Gerasimenko for the mission’s Philae lander.

Image Credit: ESA /Rosetta /MPS /UPD /LAM /IAA /SSO /INTA /UPM /DASP /IDA

A mosaic from the European Space Agency’s Rosetta spacecraft shows “Site J,” the primary landing site on comet 67P/Churyumov–Gerasimenko for the mission’s Philae lander. Rosetta is the first mission to attempt a soft landing on a comet.

The mosaic comprises two images taken by Rosetta’s OSIRIS narrow-angle camera on Sept. 14, 2014, from a distance of about 19 miles (30 kilometers).

The image scale is 1.6 feet (0.5 meters) per pixel. The red ellipse is centered on the landing site and is approximately 1,600 feet (500 meters) in diameter.

Site J is located on the smaller of the comet’s two lobes. On Nov. 12, the Rosetta spacecraft will release Philae at 01:03 a.m. PST/10:03 CET/09:03 UTC (the time the signal is received on Earth). Touchdown of Philae on Site J is expected about seven hours later, at around 8 a.m. PST/17:00 CET/16:00 UTC (Earth Received Time).

Launched in March 2004, Rosetta was reactivated in January 2014 after a record 957 days in hibernation.

Composed of an orbiter and lander, Rosetta's objectives since arriving at comet 67P/Churyumov-Gerasimenko earlier this month have been to study the celestial object up close in unprecedented detail, prepare for landing a probe on the comet's nucleus in November, and following the landing, track the comet's changes as it sweeps past the sun.

Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed.

Rosetta's lander will obtain the first images taken from a comet's surface and will provide comprehensive analysis of the comet's possible primordial composition by drilling into the surface.

Rosetta also will be the first spacecraft to witness at close proximity how a comet changes as it is subjected to the increasing intensity of the sun's radiation.

Observations will help scientists learn more about the origin and evolution of our solar system and the role comets may have played in seeding Earth with water, and perhaps even life.

ESA Rosetta Team select Landing Site J on Comet 67/P

ESA' s Rosetta lander Philae will target Site J, an intriguing region on Comet 67P/Churyumov–Gerasimenko that offers unique scientific potential, with hints of activity nearby, and minimum risk to the lander compared to the other candidate sites.

Site J is on the ‘head’ of the comet, an irregular shaped world that is just over 4 km across at its widest point.

The decision to select Site J as the primary site was unanimous.

The backup, Site C, is located on the ‘body’ of the comet.

The 100 kg lander is planned to reach the surface on 11 November, where it will perform indepth measurements to characterise the nucleus in situ, in a totally unprecedented way.

But choosing a suitable landing site has not been an easy task.

“As we have seen from recent close-up images, the comet is a beautiful but dramatic world, it is scientifically exciting, but its shape makes it operationally challenging,” says Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Center.

“None of the candidate landing sites met all of the operational criteria at the 100% level, but Site J is clearly the best solution.”

“We will make the first ever in situ analysis of a comet at this site, giving us an unparalleled insight into the composition, structure and evolution of a comet,” says Jean-Pierre Bibring, a lead lander scientist and principal investigator of the CIVA instrument at the IAS in Orsay, France.

“Site J in particular offers us the chance to analyse pristine material, characterise the properties of the nucleus, and study the processes that drive its activity.”

The race to find the landing site could only begin once Rosetta arrived at the comet on 6 August, when the comet was seen close-up for the first time. By 24 August, using data collected when Rosetta was still about 100 km from the comet five candidate regions had been identified for further analysis.

Since then, the spacecraft has moved to within 30 km of the comet, affording more detailed scientific measurements of the candidate sites. In parallel, the operations and flight dynamics teams have been exploring options for delivering the lander to all five candidate landing sites.

Over the weekend, the Landing Site Selection Group of engineers and scientists from Philae’s Science, Operations and Navigation Centre at France’s CNES space agency, the Lander Control Centre at DLR, scientists representing the Philae Lander instruments and ESA’s Rosetta team met at CNES, Toulouse, France, to consider the available data and to choose the primary and backup sites.