Surface Science from Philae – Finally!

A few weeks back, the Philae lander woke up and began transmitting the coveted science data it had been holding on to for the better part of 2015, waiting for the Sun to shine bright enough to wake it from its deep slumber.  As soon as it was able, it transmitted data back to the Rosetta orbiter, which then sent it on its long journey back home to Earth. Now that a few weeks have passed, we can finally see what the first science from the surface of 67P looks like, and determine its true fate.

Animation showing final descent to 67P. Credit: ESA/ Rosetta

We can clearly see a rock in the last image where the lander should have touched down after its seven hour descent.  This rock is potentially what caused the lander to ricochet and bounce a few times before coming to a complete stop.  The problem with this is that upon landing, Philae was pre-programmed to perform several intense science operations, many of which were carried out as it floated above the surface.  There is an upside to the bouncing, however, in that the first sets of data were taken at multiple sites and could be compared to give multiple results for the surface environment.

Mission scientists say some 80% of the initial data collection was completed by Philae during its first 64 hours of operation in November 2014, before it lost power and went into hibernation mode.  Until it awoke a few weeks ago, no contact with the lander was established and its fate was unknown.

Right after landing, instruments Ptolemy and COSAC measured chemical compositions or surface gases and dust, which are important tracers of the raw material present at the beginning of the solar system.  COSAC was placed on the bottom of the lander and measured surface dust that was kicked up, revealing 16 organic compounds made from many carbon and nitrogen-rich compounds, including four in particular that have never before been detected in comets – methyl isocyanate, acetone, propionaldehyde, and acetamide.  Ptolemy was placed atop the lander and sampled ambient gases such as water vapour, carbon monoxide, and carbon dioxide, along with smaller amounts of carbonaceous organic compounds such as formaldehyde.

The existence of such complex molecules in the early solar system means that comets like 67P could have delivered the basic building blocks for what would become prebiotic life on Earth some 4.5 Billion years ago.

I am ecstatic that after so much back and forth, we finally have the data we have waited 20 years to get from a comet, giving us new insights into the origin of our species. The comet 67P/Churyumov-Gerasimenko will reach perihelion on August 13th, 2015, its closest approach to the Sun, when the peak of outgassing and other surface processes should occur.  More great science is still to come!


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