European Space Agency makes history as probe lands on comet

Scientists have successfully landed a probe on the surface of a comet in a historic first for space exploration, the European Space Agency said yesterday. The lander, named Philae, left the Rosetta spacecraft earlier in the day. After a seven-hour descent, scientists at the ESA confirmed its safe landing on the surface of comet 67P/Churyumov-Gerasimenko, just after midnight. The first-ever landing on a comet was a crowning phase in a quest to explore the origins of the solar system, the ESA said. "We are on the comet," the ESA announced after receiving a signal from the 100kg Philae lander following its touchdown on the icy surface of the comet that is more than 500 million kilometres from earth. "We definitely confirm that the lander is on the surface," Rosetta flight director Andrea Accomazzo said. While further checks are needed to ascertain the state of the robot laboratory, the fact that it is resting on the surface of the speeding comet is already a huge success. It marks the highlight of the decade-long Rosetta mission to study comets and learn more about the origins of these celestial bodies. The head of the ESA underlined Europe's pride in having achieved a unique first ahead of its US counterpart Nasa. "We are the first to have done that, and that will stay forever," ESA director-general Jean-Jacques Dordain said. The landing caps a 6.4 billion-kilometre journey begun a decade ago in a mission that cost €1.4 billion (HK$13.5 billion). Rosetta, which was launched in 2004, had to slingshot three times around earth and once around Mars before it could work up enough speed to chase down the comet, which it reached in August. Rosetta and the comet have been travelling in tandem ever since at 6,000 km/h. The mission would also give researchers the opportunity to test the theory that comets brought organic matter and water to earth billions of years ago, said Klim Churyumov, one of the two astronomers who discovered the comet in 1969. Watch: European probe Philae makes first-ever landing on comet Scientists hope the lander, equipped with 10 instruments, will unlock the secrets of comets - primordial clusters of ice and dust that may have helped sow life on earth. The landing had been fraught with risk, given the unknown surface terrain of the comet. The team had also discovered that the thruster on board the three-legged lander, designed to help it anchor to the surface, was not functioning correctly. "We'll need some luck not to land on a boulder or a steep slope," Stephan Ulamec, Philae lander manager at the German Aerospace Centre, a member of a consortium that led the ESA mission, said ahead of the landing. But hours later, the Philae lander successfully drifted down to the comet and latched on to it using harpoons and ice screws, to ESA scientists' delight and relief. During the descent, scientists are powerless to do anything but watch, because the vast distance to earth makes it impossible to send instructions in real time. Scientists have likened the trillion or so comets in our solar system to time capsules that have remained 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 will continue to escort the comet, scanning it with 11 instruments as it loops around the Sun and makes its closest approach next year. Reuters, Associated Press, Agence France-Presse Key moments in Rosetta's inter-planetary trip March 2, 2004: Europe's unmanned probe Rosetta takes off from Kourou, French Guiana, after a series of delays, including an abandoned January 2003 launch window because of a rocket problem. February 25, 2007: Rosetta carries out a close flyby of Mars. The European Space Agency's mission control breaks out in applause after the end of 15 tense minutes of radio silence as the craft passes behind the Red Planet. September 5, 2008: Probe successfully passes close to an asteroid 400 million kilometres from earth. The spacecraft loses its radio signal for 90 minutes as planned during the flyby of the Steins asteroid, also known as Asteroid 2867. July 10, 2010: Between Mars and Jupiter, Rosetta transmits its first pictures from the largest asteroid ever visited by a satellite after it flies by Lutetia as close as 3,200km. It is the closest look to date at the Lutetia asteroid. January 20, 2014: Waking after almost three years of hibernation, Rosetta sends its first signal back to earth. Systems had been powered down in 2011 to conserve energy, leaving scientists in the dark for 31 months. August 6, 2014: Rosetta swings alongside comet 67P/Churyumov-Gerasimenko somewhere between the orbits of Mars and Jupiter. November 12, 2014: The probe releases the Philae lander towards the comet's surface. Seven hours later, Philae touches down on the comet and latches on to it using harpoons and ice screws. Associated Press

European Space Agency makes history as probe lands on comet

European Space Agency scientists behind the project overjoyed after touchdown caps a 6.4 billion-kilometre journey begun a decade ago