Early Thursday morning, Australian time, the world held its breath as a bar fridge-sized landing probe, Philae, touched down on the surface of Comet 67P/Churyumov-Gerasimenko.
The lander was released from the European Space Agency (ESA) spacecraft Rosetta, which had been travelling for ten years to rendezvous with the comet. It’s the first time ever that such a landing has been made and scientists are bursting with excitement.
Astronomer Klim Churyumov, one of the discoverers of the comet, was at ESA control headquarters at Darmstadt in Germany to watch the historic moment as it unfolded.
It’s not our first close encounter with a comet. A number of spacecraft have flown by or observed the most famous comet of them all, Halley’s Comet. These include the USSR Vega 1 and 2, ESA’s Giotto and the Japanese Susei and Sakigake deep space probes, all in 1986. In 2005, the NASA probe Deep Impact was deliberately crashed into Comet Tempel 1. The Stardust probe collected dust from around Comet Wild 2 in 2004, and then flew by Tempel 1 in 2011.
But Philae is the first soft landing, a technical feat in itself given the miniscule gravitation and all the unknowns about the terrain until parent craft Rosetta got close enough to return images.
Despite a number of problems, such as the failure of the thruster meant to stabilise the lander, Philae landed successfully and dug its foot screws into the cometary surface. Now it will begin a series of experiments that will give us unprecedented insights into the evolution of our little corner of the universe.
It’s thought that impacts with icy comets, billions of years ago, may have been responsible for a large part of the Earth’s oceans. And in their frozen cores, comets like 67P/Churyumov-Gerasimenko may preserve the chemical signature of the early solar system.
Next, Rosetta and Philae together will accompany the comet as its orbit swings around the sun, hitchhiking their way into history.
Dr Alice Gorman, based in Flinders University’s Archaeology Department, is an internationally recognised leader in the emerging field of space archaeology. You can follow Dr Gorman on Twitter @DrSpaceJunk