Spacecraft lands on comet 4 billion miles away
Hundreds of millions of miles from Earth, a spacecraft made history Wednesday. It landed on the icy, dusty surface of a speeding comet. It was an audacious cosmic first designed to answer big questions about the origin of the universe.
Paolo Ferri, head of mission operations for the European Space Agency, said the landing on the comet named 67P/Churyumov-Gerasimenko appeared to have been almost perfect.
"Everyone cried," he said.
The European Space Agency celebrated the cosmic achievement. The agency had sweated through a tense seven-hour countdown. It began when the Philae lander dropped from the agency's Rosetta space probe as both it and the comet hurtled through space at 41,000 mph.
ESA controllers clapped and embraced at mission control in Darmstadt, Germany. That came after the Rosetta space probe had successfully released the 220-pound, washing machine-sized Philae lander.
During the descent, scientists were powerless to do anything but watch. That's because the vast distance to Earth, 311 million miles, made it impossible to send instructions in real time.
Finally, the agency received a signal from Philae. It had touched down on the comet's icy surface.
"We definitely confirm that the lander is on the surface," said flight director Andrea Accomazzo.
Further checks are needed to ascertain the state of the lander. But the fact that it is resting on the surface of the comet is already a huge success. It is the highlight of a decade-long mission to study comets.
Scientists want to learn more about the origins of these celestial bodies. They have likened the trillion or so comets in our solar system to time capsules. That's because they are virtually unchanged since the earliest moments of the universe.
"By studying one in enormous detail, we can hope to unlock the puzzle of all of the others," said Mark McCaughrean, a senior scientific adviser to the mission.
Rosetta and Philae now plan to accompany the comet as it races past the sun and becomes increasingly active in the rising temperatures.
"The science starts the minute we get down to the ground," McCaughrean said.
The landing capped a 4 billion-mile journey that began a decade ago. Rosetta was launched in 2004. It had to slingshot three times around Earth and once around Mars before it could work up enough speed to chase down the comet. Rosetta and the comet have been traveling in tandem ever since.
The mission will also give researchers the opportunity to test the theory that comets brought organic matter and water to Earth billions of years ago. That's according to Klim Churyumov, one of the two astronomers who discovered the comet in 1969.
The lander's batteries are expected to last just 64 hours. But that should be enough for scientists to gather a huge wealth of data. In addition, the lander has a solar panel that should be able to provide an hour's worth of battery life each day.
The lander should remain stuck to the comet forever, even after its systems have shut down.
Critical thinking challenge: Why was Rosetta launched in 2004, yet only landed this week?
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