14 DAY TRIAL // For the next 31 months, the Rosetta spacecraft will remain in hibernation mode, experts at the European Space Agency (ESA) announced yesterday, June 8. They say that the final commands have been sent to the spacecraft, which is now on its way to meet comet 67-P/Churyumov-Gerasimenko.
It has now entered the longest leg of its journey, and there is no longer a point in keeping all of its instruments going. As such, ESA mission managers decided to shut the spacecraft down until January 20, 2014, leaving only a few heaters operational.
The spacecraft is powered by solar panels, and has already exceeded the record for longest-traveling space probe equipped with this technology. At its current distance from Earth, the panels cannot provide the amount of energy needed to operate the entire vehicle.
While in hibernation mode, Rosetta will save large amounts of energy, that it would have otherwise spent doing nothing. A timer has been set in motion, ESA experts say, and the spacecraft will awake only when the count reaches zero.
This will happen less than three years from now, as Rosetta makes its way farther and farther out into the vastness of the solar system. It is scheduled to travel for millions of kilometers of space.
The orbit in which the spacecraft is placed around the Sun has its apogee at 790 million kilometers away. Currently, the probe is some 550 million kilometers away from the star. By 2014, it will distance itself from the Sun, and then it will move towards the inner solar system again.
“We sent the [hibernation mode] command via NASA's 70[-meter] Deep Space Network station in Canberra, Australia, ensuring the signal was transmitted with enough power to reach Rosetta, which is now 549 million [kilometers] from Earth,” says Andrea Accomazzo.
“We'll monitor via ESA's 35[-meter] station at New Norcia in Australia for a few days to see if any problems occur, but we expect to receive no radio signal until 2014. Rosetta's on her own now,” adds the official, who is the Spacecraft Operations Manager at ESA.
When the spacecraft comes back online, experts will gradually begin to heat it up. This is scheduled to take a few months. By July 2014, the probe will be in perfect shape for its rendezvous with the comet.
“A special hibernation mode of the spacecraft was designed by engineers at EADS Astrium, the main industrial prime contractor that build Rosetta, to allow it to survive the large distances from the Sun during its cruise,” an ESA press release says.
“At 08:00 UT (10:00 CEST) [on June 8], Rosetta automatically started spinning, which will stabilize the probe while the normal attitude control system is off throughout hibernation, and at 12:58 UT (14:58 CEST) the final shut-down command was sent,” the statement adds.