The Rosetta Spacecraft Is About to Intercept a Comet Going Mach 47

The European Space Agency's Rosetta spacecraft will finally complete its 10 year journey to intercept the comet 67P/Churyumov–Gerasimenko on Wednesday. Now comes the hard part.

The Rosetta spacecraft is currently travelling at about 36,000 mph—that's roughly mach 47. Comet 67P, meanwhile, is moving through space at 34,175 mph. In order for the Rosetta to intercept and enter orbit around the comet, it's going to have to match the comet's speed within a range of just 1 mph. So, to slow itself down sufficiently, the Rosetta performed a series of thruster burns in June and July to cut 1500 mph off its trajectory, while another pair of "insertion burns" performed yesterday and today should put the spacecraft in optimal position to snag the passing space rock.


Once that happens, the Rosetta will spend 18 months examining the comet before deploying a landing craft known as the Philae. This would mark the first time in recorded history that human technology has not only orbited a comet, but landed and sampled it as well. [Space]

The Rosetta Spacecraft Is Humanity's First Asteroid Lander

While NASA's asteroid-capturing mission remains grounded from a lack of Congressional funding, a similar and equally ambitious ESA program is nearing fruition. In the coming months, the Rosetta spacecraft and its integrated Philae probe will become the first manmade objects to not only orbit an asteroid but land on it as well. Here's how they'll do it.

The European Space Agency began work on the Rosetta spacecraft in the early 1990s as part of the Horizon 2000 missions, and launched the spacecraft towards its target, 67P/Churyumov–Gerasimenko, in March of 2004 aboard an Ariane 5 rocket. For nearly a decade, the spacecraft has slowly wound its way to towards the asteroid but is expected to finally arrive in November of next year.


Once the Rosetta reaches 67P, it will spend an additional 17 months orbiting the asteroid. The Rosetta orbiter packs a dozen instruments including various infrared, ultraviolet, optical, and spectroscopic imaging systems as well as microwave and radar sounders and a variety of gas and particle analyzers. These systems will allow the orbiter to study both the surface structure and core of the asteroid—as well as its chemical composition—before attempting the a risky landing maneuver with the Philae probe.

The Philae itself is a 220 kg carbon fiber landing craft designed to deploy from the Rosetta and fall towards the asteroid in a ballistic trajectory. Impact dampening legs and anchoring harpoons will ensure that the lander doesn't simply bounce off 67P and float off into the depths of space. If it does safely land on the asteroid, Philae's mission is expected to last between a week and a few months, as its array of nine sounders and particle analyzers go about exploring 67P's internal structure.


It may not be as cool as NASA's plan to net a space rock with an autonomous robot and tow it home like a celestial deer strapped to the roof of a Buick, but the ESA's Rosetta mission will provide us with vital, and in some ways, basic knowledge about the untold numbers of asteroids that also inhabit our solar system. [ESA - Space - Wiki]