Rosetta spacecraft to fling itself at comet in a suicide mission

For a billion miles, the tireless spacecraft called Rosetta has shadowed an icy comet through the solar system, enduring dust storms, fountains of gas and the comet’s mood swings.

Now, faithful to the end, Rosetta is about to join the comet for eternity.

Early on Friday,  the craft will smash in slow motion onto the comet. Moving at the pace of a stroll, Rosetta will touch down, bounce and eventually come to rest, probably breaking its solar panels or instrument booms as it tumbles. No word from it will ever reach Earth again.

It’s “unusual to end a mission by actually crashing it into the thing you’ve been studying,” says Christopher Carr of Britain’s Imperial College London, who works on the mission. “We’ll be quite emotional when we finally see that last bit of data.”

Rosetta’s legions of fans don’t want to bid goodbye. But as the spacecraft follows the comet, both are traveling ever further from the sun, starving the ship of the solar power it needs.

Rather than sending Rosetta on a suicide mission, managers at the European Space Agency could simply turn it off. But then it would become “another piece of junk in the solar system,” says Jean-Baptiste Vincent of Germany’s Max Planck Institute for Solar System Research, another scientist working on the mission.

By sending Rosetta on a collision course with its comet, the spacecraft’s handlers will not only keep the celestial neighborhood tidy but will also collect priceless data. The ship’s cameras, for instance, should snap pictures until the spacecraft is just 50 feet above the comet’s surface. Other instruments will also keep running as scientists hold their breath that everything works. “You can only do it once,” Carr says.

Rosetta will smack down onto an intriguing region called Ma’at, which is dotted with pits deep enough to hide Washington D.C.’s Lincoln Memorial. Scientists have determined the pits are sources of dust jets blasting from the comet, and researchers are anxious to learn more about the pits’ role.

Unfortunately Rosetta’s grave will not be close to that of its fellow-adventurer Philae, a mini-craft that journeyed aboard Rosetta from Earth and then made a bold bid to land on the comet. Philae survived a perilous touchdown in 2014, but its deeply shadowed resting spot receives too little sunlight to power its electronics. Earlier this year, mission controllers gave it up for dead.

Philae was finally spotted a few weeks ago, tipped on its side. Rosetta will land halfway around the comet from Philae, and the path of its descent won’t allow the mother ship to photograph its errant offspring.

Rosetta’s self-destructive plunge will cap a glorious career. Other spacecraft have only glanced at comets while hurtling by. Rosetta, on the other hand, spent more than two years at the mountain-sized comet Churyumov-Gerasimenko, which was named for the Ukrainian scientists who discovered it in 1969.

Through Rosetta, scientists discovered a strange world of landslides and pits, mountains and plains. Rosetta discovered organic molecules – crucial biological ingredients – on the comet, providing support for the theory that comets seeded Earth with some of the building blocks for life. And it sniffed out clues that the solar system formed at a colder temperature than expected, forcing scientists to revise their ideas for the system’s evolution.

Though it may seem strange to crash-land a functioning spacecraft, “that’s the best way to do it,” says the University of Michigan’s Tamas Gombosi, a scientist working on the Rosetta team. “The last few hours, we will have absolutely unique data, there’s a grand finale and then the fat lady stops singing.”