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Goodnight Rosetta, sleep tight!

ESA space probe has been put into hibernation

On Wedneday 8 June, the Rosetta space probe developed and built under the leadership of Airbus Defence and Space (Friedrichshafen) was put into hibernation by the European Space Agency (ESA). At the invitation of the European Space Operations Centre (ESOC), Airbus Defence and Space systems engineer Alois Eibner performed the honourable task of sending the last radio command (for the time being) to the space probe. The command took 29 minutes to reach the comet hunter. “Rosetta is now locked in ‘sleep’ mode,” explains Alois. “The comet probe will not wake up again before January 2014.”

Airbus Defence and Space systems engineer Alois Eibner will send the last radio command (for the time being) to the space probe on Wednesday 8 June 2011.

When the team in the ESOC Control Centre in Darmstadt, Germany, ‘talked’ for the last time to Rosetta, which was launched on 2 March 2004, the probe was at a distance of 654 million kilometres from the Earth and had travelled 5,500 million kilometres through space. Before Rosetta reaches its destination, the comet 67P/Churyumov-Gerasimenko, it will have to travel another 1,600 million flight kilometres. During the 32 months of deep sleep, the probe, weighing approximately three tonnes, will essentially be left to its own devices. Radio contact will no longer be possible, as there is not enough solar energy for all on-board systems during this phase. Never before has a solar-powered space vehicle ventured into these depths of space, further away from the sun than the planet Jupiter. Rosetta has to take that risk in order to reach the comet.

To make sure the probe is ‘wide awake’ when it reaches its destination, engineers have set the on-board ‘alarm’: a clock with triple redundancy will wake the comet hunter in good time before its scheduled rendezvous. In July 2014, Rosetta will then be able to approach 67P/Churyumov-Gerasimenko, which has a size of just 3 x 5 kilometres.

For the scientific community, the Rosetta mission is comparable to a journey into the past, a journey to the primeval times of our solar system. In contrast to planets where tectonics and erosion have permanently changed the rocks, the material inside comets has remained unchanged since the time of their formation approximately 4.6 billion years ago. The comets can be regarded as deep-freeze archives which scientists will now try to decipher. For about two years Rosetta will orbit the comet at a low altitude and investigate its nucleus and environment. A lander will perform scientific surface investigations and analyses.