Leonard David's INSIDE OUTER SPACE

Jet streams on Churyumov-Gerasimenko
A prominent jet, together with gas an dust outflows are visible in this four-image mosaic, created from images acquired by Rosetta’s Navigation Camera NAVCAM on January 31, 2015. The comet’s activity will increase as it approaches the Sun.
Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0.

Scientists on the European Space Agency’s Rosetta comet mission suggest that Comet 67P/Churyumov-Gerasimenko could lose up to over 65 feet (20 meters) of surface material from its previously unilluminated south side when it heats up, starting in May 2015.

This possible estimate of erosion of 67P comes via data acquired by Rosetta’s Optical, Spectroscopic and Infrared Remote Imaging System (OSIRIS).

Model calculations for the erosion of 67P/Churyumov-Gerasimenko
This image is based on a surface model of comet Churyumov-Gerasimenko and shows the predicted extent of erosion of cometary material.
The left figure shows the comet seen from the north; the center image shows the equatorial plain and the right image shows the southern region. The different colours represent the predicted amount of erosion – the southern part of the comet could lose up to 20 meters of surface material during the orbit.
Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA/DLR .

“The comet sheds its surface almost constantly, revealing fresh material on its surface, which has not yet been aged by cosmic radiation,” says Ekkehard Kührt, who leads the Rosetta mission science team at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR).

The Rosetta orbiter and its lander, Philae, will have an excellent view of the comet as it awakens and ejects gases and dust into space.

Lander wake-up call

The Philae lander now resting on the comet will be able to take advantage of the summer; at its location near the equator, it may receive sufficient sunlight to “wake up” from its current hibernation state. This might occur as early as March, but the probability that the Lander Control Center will resume contact and be able to send commands will be greatest in May, according to a DLR press statement.

The comet’s closest approach to the Sun (perihelion) will occur in August 2015.

The increasing heat as the comet approaches the Sun will trigger this “diet”, during which gases and solid materials will be ejected into space.