Forget the moon landing! How about a comet landing?
On November 12th, 2014, a tiny probe named Philae made history by becoming the first man-made object to touch down on the surface of a comet. Yet, Philae would’ve never reached the comet in the first place without another, far more important probe: Rosetta.
Launched by the European Space Agency in 2004, Rosetta was a solar-powered probe which travelled space for 12 years. Only recently, it ended its great odyssey on September 30th, when it crashed into the comet it had been studying. It is known as the comet 67P, or as Churyumov-Gerasimenko. The comet itself measured a relatively small four by five kilometres, and is composed of low density ice and dust.
Rosetta’s grand journey began with reaching the comet 67P. This proved to be difficult because, unlike planets and moons which orbit the sun at a relatively slow pace, comets race across the galaxy at alarming speeds. To catch up to such a fast moving object, the probe had to orbit the sun loop the Earth and planet Mars a couple times so their gravity would increase its speed. This technique took Rosetta over a decade to perform. Two and a half of those years were spent in hibernation.
Rosetta’s actual explorations of the comet involved launching the small probe Philae onto the celestial body’s surface, accompanying it on its orbit around the sun while photographing the comet’s tail from close up.
Unfortunately, as the comet began moving farther and farther away from the Sun, Rosetta’s solar panels could no longer produce enough energy to power it. Rather than let the probe float aimlessly through space, controllers crashed Rosetta on the comet 67P.