Comet landing
LONG TREK: HISTORY AS ROBOT LAB REACHES TARGET
Minilab designed to piggyback ‘67P’ and probe its chemistry and structure.
AEuropean probe landed on a comet yesterday, the culmination of a historic quest to explore an enigma of the solar system. After a trek of more than a decade, covering 6.5 billion kilometres, a minilab called Philae separated on schedule from its mother ship, Rosetta.
The probe did not anchor to comet 67P/Churyumov-Gerasimenko after landing harpoons failed to fire, but still managed to send home lots of data, the European Space Agency (ESA) said yesterday.
“The lander is not anchored to the surface,” Philae lander manager Stephan Ulamec told reporters at ground control in Darmstadt, Germany. “We still do not fully understand what has happened,” he added.
Fluctuations in radio signals suggested Philae had either landed “in a soft sandbox” or had gently rebounded from the surface and returned to it.
Philae was placed on a trajectory to land on “67P”, a comet now more than 510 million kilometres from Earth and racing towards the sun.
Scientists faced a seven-hour wait to see if the bet came off, their nerves stretched by a nonfatal last-minute glitch. But cheers erupted as the confirming signals were received at the European Space Operations Centre in Darmstadt, Germany.
Comets are believed to be clusters of primordial ice and carbon dust left over from the building materials of the solar system.
They are doomed to circle the sun in orbits that can range from a few years to millennia.
The robot lab Philae was designed to piggyback comet “67P” and probe its chemistry and structure with instruments.
“Now it’s down to the laws of physics. We’re on the way to the surface,” said ESA’s senior science adviser, Mark McCaughrean.
But the gamble paid off and Stefan Ulamec, Philae lander manager, said: “It is sitting on the surface. Philae is talking to us – we are on the comet.” Earth received the signal at about 4pm GMT.
The € 1.3 billion (R14 billion) mission was approved in 1993.
Rosetta, carrying Philae, was hoisted into space in 2004 and took more than a decade to reach its target in August this year.
I don’t have fingernails, so I won’t be biting them Mark McCaughrean ESA’s senior science adviser
Turning slowly around “67P” ever since, Rosetta has made some astonishing observations.
The comet’s profile somewhat resembles that of a rubber bath duck – but is darker than the blackest coal, its surface gnarled and battered by billions of years in space.
It has a treacherous, irregular surface – an extremely difficult target to land on.
The big test was for Philae to settle safely as Rosetta and 67P zipped towards the sun at 18km per second.
If it had come to grief, scientists would have been hugely disappointed, but Philae accounts for only about a fi fth of the mission’s total expected data haul.
Rosetta will continue to escort the comet as it loops around the sun and makes its closest approach next year. –