2014年11月12日 星期三

Philae spacecraft makes historic landing on comet


【十年太空夢首次登陸彗星 人類文明邁出巨大一步】文: 場邊故事
今次漫長的太空旅程得來不易,飛船十年前啟航,曾繞地球三次,借助地球的重力揈到老遠的木星軌道附近,追上彗星 67P。靠太陽能推動的飛船曾因為距離太陽太遠,無力前行,控制中心唯有把它「催眠」,讓它在太空沉睡了兩年半,期間和地球失去聯絡。後來在預定時間甦醒及向 67P 最後進發,歐州太空署才鬆一口氣。

  • Philae spacecraft makes historic landing on comet
    The Guardian - 41 mins ago
    Philae is talking to us,” said a jubilant Stephan Ulamec, Philae lander manager at the DLR ...

  • Philae spacecraft makes historic landing on comet

    Rosetta mission’s safe landing gives scientists their first chance to ride a comet and study close up what happens as it gets closer to the sun

    • Rosetta mission landing: follow the live reaction
    • See the historic landing in pictures
    • Usama Hasan: mission will help illuminate origins of life

    The European Space Agency mission control in Darmstadt, Germany, celebrates as Philae touches down
    The signal broke a seven-hour wait of agonising intensity and sparked scenes of jubilation at the European Space Agency’s mission control in Darmstadt. The team in charge of the Rosetta mission achieved what at times seemed an impossible task by landing a robotic spacecraft on a comet for the first time in history.
    The moment the tension broke came shortly after 1600 GMT when the Philae called home. “We are there. We are sitting on the surface. Philae is talking to us,” said a jubilant Stephan Ulamec, Philae lander manager at the DLR German space centre. “We are on the comet.”
    Andrea Accomazzo, the Rosetta flight operations director, added: “We cannot be happier than we are now.”
    But celebrations were tempered by the later discovery that the probe’s two harpoons had not fired to fasten the craft down in the ultra-low gravity. Scientists now think the probe may have bounced after first coming into contact with the surface. Ulamec said: “Maybe today we didn’t just land once, we landed twice.”
    The safe, if precarious, touchdown of the lander gives scientists a unique chance to ride onboard a comet and study from the surface what happens as its activity ramps up as it gets closer to the sun. The first images beamed back from the lander’s descent revealed a dramatic landscape of pits and precipices, craters and boulders. However, there have been gaps in its radio link with the orbiting Rosetta mothership. 

    Philae lander lander seen from Rosetta
    The Philae lander on its way to the comet, photographed by the Rosetta spacecraft.Photograph: AP

    The £1bn ($1.58bn) Rosetta mission aims to unlock the mysteries of comets, made from ancient material that predates the birth of the solar system. In the data Rosetta and Philae collect, researchers hope to learn more of how the solar system formed and how comets carried water and complex organics to the planets, preparing the stage for life on Earth.
    Space agencies have sent probes to comets before, but not like this. In 1986, Nasa’s Ice mission flew through the tail of Halley’s comet. In 2005, the agency’s Deep Impact spacecraft fired a massive copper block at comet Temple 1. But none before now has landed.
    The feat marks a profound success for the European Space Agency (ESA), which launched the Rosetta spacecraft more than 10 years ago from its Kourou spaceport in French Guiana. Since blasting off in March 2004, Rosetta and its lander Philae have travelled more than 6bn kilometres to catch up with the comet, which orbits the sun at speeds up to 135,000km/h.
    “We are the first to do this, and that will stay forever,” said Jean Jacques Dordain, director general of the ESA.
    Matt Taylor, a Rosetta project scientist, who had selected an extremely colourful shirt for the event, revealed an impressive – and brave – tattoo of the lander on the comet’s surface.