Philae lander data reveals presence of building blocks of life on comet

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The Comet 67P/Churyumov­-Gerasimenko packs some of the key building blocks of life including some that play a key role in the prebiotic synthesis of amino acids, sugars and nucleobases, the European Space Agency (ESA) said based on analysis of data collected by its Philae lander.

Published in a special edition of the journal Science, the early results from Philae’s first suite of scientific observations of comet 67P reveal a range of things including the complex molecules that could be key building blocks of life, the daily rise and fall of temperature, and an assessment of the surface properties and internal structure of the comet.

ESA said that the lander completed some 80 per cent of the first science sequence in the 64 hours following Philae’s separation and before it went into hibernation. ESA said that the added bonus was that the lander managed to collect data from spots during its multiple touchdowns enabling scientists to compare data between the touchdown sites.

Data were obtained during the lander’s seven-hour descent to its first touchdown at the Agilkia landing site, which then triggered the start of a sequence of predefined experiments. However, shortly after touchdown Philae rebounded and so a number of measurements were carried out as the lander took flight for an additional two hours some 100 m above the comet, before finally landing at Abydos.

ESA said that soon after its first touchdown at Agilkia, Philae’s gas-sniffing instruments Ptolemy and COSAC analysed samples entering the lander and determined the chemical composition of the comet’s gas and dust, important tracers of the raw materials present in the early Solar System. COSAC analysed samples entering tubes at the bottom of the lander kicked up during the first touchdown, dominated by the volatile ingredients of ice-poor dust grains revealing a suite of 16 organic compounds comprising numerous carbon and nitrogen-rich compounds, including four compounds – methyl isocyanate, acetone, propionaldehyde and acetamide – that have never before been detected in comets.

Ptolemy on the other hand sampled ambient gas entering tubes at the top of the lander and detected the main components of coma gases – water vapour, carbon monoxide and carbon dioxide, along with smaller amounts of carbon-bearing organic compounds, including formaldehyde.

ESA says that some of the compounds detected by Ptolemy and COSAC play a key role in the prebiotic synthesis of amino acids, sugars and nucleobases: the ingredients for life. For example, formaldehyde is implicated in the formation of ribose, which ultimately features in molecules like DNA.

The existence of such complex molecules in a comet, a relic of the early Solar System, imply that chemical processes at work during that time could have played a key role in fostering the formation of prebiotic material.

“With Philae making contact again in mid-June, we still hope that it can be reactivated to continue this exciting adventure, with the chance for more scientific measurements and new images which could show us surface changes or shifts in Philae’s position since landing over eight months ago,” says DLR’s Lander Manager Stephan Ulamec.

“These ground-truth observations at a couple of locations anchor the extensive remote measurements performed by Rosetta covering the whole comet from above over the last year,” says Nicolas Altobelli, ESA’s acting Rosetta project scientist.