Landing on a Comet

The origin of the Rosetta mission goes back to May 1985 when a meeting took place by the European Space Agency that laid the ground work for “Horizon 2000”. The primary component was the crazy idea to visit a comet, collect samples, and bring them back to Earth. Originally the probe was preconceived to be a nuclear powered vessel developed with the help of NASA, who was developing a related mission called Comet Rendezvous/Asteroid Flyby (CRAF).

Things didn’t go as planned, of course. Early in the 1990s, budget cuts forced NASA to cancel CRAF and pull out of the Rosetta project. This forced it to become a smaller solar-powered project that would no longer return samples to Earth. Version 2 contained the production of two landers, but further NASA cutbacks left the project with it’s final Rosetta-Philae mission.

After a failed rocket launch and a missed opportunity at the originally chosen comet, the ESA decide on their next target, Comet 67P, a “rubber duck” shaped comet of two separate forms fused together. Although the shape made it much more interesting to explore, it also made it a great deal more challenging. Engineers had to design downward thrusters and a dual system to anchor it to this comet of minimal gravity.

As Rosetta watched from above, the Philae lander bounced off the comet three times before landing in a ravine where it’s solar panels received only 1.5 hours of sunlight per day, not enough to keep its batteries charged.

Prepared for the worst, the mission planners designed Philae to perform its experiments in the first 54 hours of landing. The surface composition did not look good for being a key seeder of water for planets like Earth. 

On August 13, Comet 67P will reach its nearest point to the sun known as perihelion. This is when things will really get interesting as the surface begins to evaporate and Philae begins to “wake up”.

What will Philae see as it nears the sun? Will we be able to watch Comet 67P disintegrate and transform its landscape as it moves closer to the sun? It is safe to say that you should expect the unexpected as we all should in every scientific exploration.

Where is Rosetta Today?

Philae wakes up:Welcome_to_a_comet

After 211 days of hibernation, Philae wakes up on June 13 and relays a signal to Rosetta. The lander is in good condition and generating enough power to begin a few scientific measurements. The next task is to get Rosetta in an optimal orbit for communication with the lander and to establish regular and predictable contacts.

Exposed:Colour_composites_of_icy_bright_patches_on_comet

Clusters of bright features have emerge, possibly due to recent erosion or collapsing of the cliff walls displaying new material from below the dust-covered surface. When viewed at visible wavelengths, these areas appeared bluer in color compared to the red background surface of the comet. “Water ice is the most plausible explanation for the occurrence and properties of these features,” says Antoine Pommerol of the University of Bern and lead author of the study.

Monitoring active jets:

Heat is causing the subsurface ice to sublimate, conversion of solid to gas, from sinkholes. The new material exposed is sending out jets, emitting from the interior walls of the pits. The internal characteristics of each pit varies significantly. “We think that we might be able to use the pits to characterise the relative ages of the comet’s surface: the more pits there are in a region, the younger and less processed the surface there is,” explains Jean-Baptiste Vincent from the Max Planck Institute for Solar System Research, lead author of the study. The theory suggest that active pits are the youngest, middle-aged pits have boulders on their base dislodged from the sides, and older pits have degraded rims and are filled with dust.

Need a bit more interactive activity? 

Visit this wonderful 3-D time-lapse of the mission.

 

Featured image photo by ESA-European Space Agency