Spacecraft With Comet-Landing Destiny Wakes From Three-Year Hibernation
While the United States prepares to lasso an asteroid and drag it into Earth's orbit, the Europeans are planning another rodeo-type mission by landing a small spacecraft on a raging comet. The comet lander, called Philea, has been on its way to deep space for the last 10 years and in hibernation mode for the last three.
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On Friday, the European Space Agency woke Philea from its dormant state to begin a few weeks of rebooting procedures before beginning its final descent sometime next year, the BBC reported. The target is a comet called 67P/Churyumov-Gerasimenko, named for the astronomers who discovered it. The nice thing about 67P is its regularity. Some comets hang out in the Oort Cloud all their lives and never come toward the sun, while others are kamikaze comets, swooping in for a long orbit around the sun then fizzling out, like the recent ISON comet did. 67P, on the other hand, consistently orbits the sun every 6.5 years between the Earth and Jupiter.
The spacecraft has two parts: an orbiter called Rosetta and a lander called Philea. Right now, Philea is attached to Rosetta. When they rendezvous with the comet sometime next year, they'll start to orbit the nucleus 67P, the first time human instruments have ever orbited a comet. It won't be easy. 67P is an irregular shape about 2 miles by 3 miles across. Because it's so small, it's gravity is very weak.
Half the time, 67P is just a ball of ice and rock, drifting safely distant from the sun. But when it hurtles inside Mars' orbit, the solar wind melts some of the ice and causes the characteristic comet tail to form. That's what scientists really want to see. By then, Philea will have jettisoned onto the surface of the comet, known as the nucleus, and drilled its legs into the rock. There it will take pictures and measurements and send them back to Earth. "Rosetta will be the first spacecraft to examine from close proximity how a frozen comet is transformed by the warmth of the Sun," according to the European Space Agency.
The BBC reports that as of Friday, the Rosetta spacecraft was 407 million miles from Earth and just 2.4 million miles from 67P. It was close enough that Rosetta's camera, called OSIRIS, was able to take its first pictures of the comet. "Finally seeing our target after a 10-year journey through space is an incredible feeling," OSIRIS Principal Investigator Holger Sierks told Astronomy Magazine. "These first images taken from such a huge distance show us that OSIRIS is ready for the upcoming adventure."
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