European comet-chasing spacecraft Rosetta has woken up from 31 months of hibernation, successfully sending the first signal to its ground control centre on Monday evening.
The operation, performed by the European Space Agency’s (ESA) controllers from the operations centre in Darmstadt, Germany, ended a long chapter of uncertainty and has put the spacecraft on its course to meet with the Comet 67P/Churyumov-Gerasimenko later this year.
Engineers put the spacecraft, launched in 2004, to sleep in June 2011 to reduce its energy requirements as it was hurtling through space some 800 million kilometres away from the Sun, near Jupiter. At such a distance from the Sun, the spacecraft, powered solely by its solar panels wouldn’t have had enough energy.
Until yesterday, the scientists were uncertain whether the sleeping spacecraft and its systems survived in the harsh outer space environment intact.
“This was one alarm clock not to hit snooze on, and after a tense day we are absolutely delighted to have our spacecraft awake and back online,” said Rosetta’s mission manager Fred Jansen after the first signal was received at 6:17pm GMT on Monday.
The eagerly awaited first signal was received by Nasa’s Goldstone ground station in California nearly eight hours after Rosetta’s inner clock switched on the spacecraft’s systems, turning on its startrackers and transmitters.
“We have our comet-chaser back,” said Alvaro Giménez, ESA’s director of Science and Robotic Exploration. “With Rosetta, we will take comet exploration to a new level. This incredible mission continues our history of ‘firsts’ at comets, building on the technological and scientific achievements of our first deep space mission Giotto, which returned the first close-up images of a comet nucleus as it flew past Halley in 1986.”
Now travelling some 673 million kilometres from the Sun, Rosetta has enough energy to embark on the most important and most challenging part of its mission, approaching the Comet 67P/Churyumov-Gerasimenko, entering its orbit and landing a small rover on its surface in November 2014.
Before reaching its destination, the spacecraft will have to travel more than nine million kilometres, allowing the controllers enough time to perform essential health checks and turn on scientific instruments.
“We have a busy few months ahead preparing the spacecraft and its instruments for the operational challenges demanded by a lengthy, close-up study of a comet that, until we get there, we know very little about,” said Andrea Accomazzo, ESA’s Rosetta operations manager.
Rosetta is expected to capture first images of 67P/Churyumov-Gerasimenko in May and start preparations for the rendezvous in August. From the comet’s orbit, the spacecraft will perform critical measurements of the comet’s mass, shape, gravity and chemical composition, providing the scientists with data to choose the most convenient site to drop the 100kg Philae lander.
“All other comet missions have been flybys, capturing fleeting moments in the life of these icy treasure chests,” said Matt Taylor, ESA’s Rosetta project scientist. “With Rosetta, we will track the evolution of a comet on a daily basis and for over a year, giving us a unique insight into a comet’s behaviour and ultimately helping us to decipher their role in the formation of the Solar System.”
The mission is expected to last until the end of 2015. Before having been put to deep space hibernation in 2011, it performed three Earth flybys, travelled near Mars once and captured images of two asteroids.