Early tomorrow morning, a spacecraft that was launched more than ten years ago will, with any luck, achieve the first landing on a comet. The European Space Agency’s Rosetta spacecraft was launched in March 2004, and has had a long journey. During several orbits around the sun, Rosetta has completed four slingshot maneuvers to boost its speed; three around the earth, and one around Mars.
Its destination is Comet 67P/Churymov-Gerasimenko, or more simply, Comet 67P, which is an oddly shaped comet. The comet is about three miles long by roughly two miles at its widest point. Being classed as a Jupiter Family comet, its orbit doesn’t extend as far away from the sun as some other comets, only extending a ways beyond the orbit of Jupiter. and it has a relatively short orbital time of about six and a half years.
Including its solar panels, the Rosetta is about 105 feet in length, and is the first spacecraft to rely only on its solar cells to generate power. The lander, called Philae, carries drills for sampling below the surface of the comet, along with ovens to heat the material so gases can be drawn off and analyzed by the onboard spectrometer. Rosetta and Philae will continue to stay with Comet 67P for approximately the next two years, with Philae essentially riding the comet as it approaches perihelion next year.
About 8:35 AM GMT (3:35 AM EST), the Philae lander will separate from Rosetta and attempt to land on the comet. This landing will not be a piece of cake. The gravity of Comet 67P is so low that Philae will drive two harpoons into the comet’s surface to anchor itself and prevent it from drifting away. These harpoons will become more important as the comet approaches the sun, because as it heats up, the outgassing that will occur could push the lander away from the surface.
Even so, there’s a chance something could go wrong; Philae could be at a slightly wrong angle, bounce off the surface upon contact and never get the chance to fire those harpoons to secure itself to the comet. Assuming all goes well with the journey to the comet’s surface, the landing is estimated to take place around 4 PM GMT/11 AM Eastern.
Live coverage of the mission can be seen at the ESA website and at the NASA website. Because of the distance from Earth to the comet, the signals from Philae will take a little over 28 minutes to reach us, so hopefully within an hour or so after the landing, we should start to see some photos of the comet’s surface. According to Matt Taylor, who works with the mission at the European Space Agency, the data comes in too slowly for video to be possible.
Attempting to land on a comet has never been done before, and I’ll be keeping an eye on how everything goes. All good success to those working with Rosetta and Philae – let’s hope everything goes perfectly.
Update 12 November: As of a couple of minutes after 4 PM today (GMT) it was confirmed that the lander, Philae, had successfully landed on the comet. Congratulations to the European Space Agency, NASA, and all who worked on this mission!