Concluding the end of the European Space Agency’s (ESA) Rosetta mission on September 30 2016, was the controlled impact of the spacecraft onto comet 67P.
Originally launched in 2004, the Rosetta spacecraft arrived at comet 67P on August 16, 2014 and deployed a space lander named Philae onto its surface. But, on impact, when the space lander was supposed to deploy two harpoons to secure it to the surface – and a thruster to do the same – the lander bounced, landed in a shadow, and both harpoons failed to fire. Philae was the first spacecraft to land on the surface of a comet.
After 2 days on the surface, Philae shut down and went into hibernation mode, due to the lack of sunlight to power the batteries. Contact was sporadic and was eventually lost. Since then, Rosetta has orbited the comet and completed five orbits of the sun.
Because the orbit of the spacecraft would eventually take the space probe out of reach of the sun’s solar energy – with no guarantee that the probe would survive a further hibernation period – the decision was made to steer it into the trajectory of the comet itself, thereby collecting further readings and taking the clearest pictures of 67P’s surface, yet. The last photo taken just 20 metres (66 feet) from its surface.
67P was discovered by Klim Ivanovich Churyumov in 1969, when he examined a photograph that was originally exposed for comet 32P, but noticed 67P after further examination. It was originally on another orbit until Jupiter’s gravity changed it.
Instruments from Rosetta showed that the water vapour found on 67P was vastly different to that on Earth, having three times more deuterium to hydrogen than found in terrestrial water. Also, readings showed that there were sixteen organic compounds found in 67P’s makeup, four of which were found on a comet for the first time. Those compounds being acetamide, acetone, methyl isocyanate, and proprionaldehyde.
Astrobiologists Chandra Wickramsinghe and Max Wallis proposed the idea that many of the features of 67P, such as its organic-rich type crust may be due to the presence of extra-terrestrial microorganisms; however, the scientists from the Rosetta programme discredit this as speculation.
For the ESA, it was a bitter-sweet ending to the Rosetta mission, but as Alvaro Giminez, the ESA director of science said, “This mission has spanned entire careers, and the data returned will keep generations of scientists busy for decades to come.”