The European Space Agency (ESA) has switched off its radio link to Philae comet lander – one of the steps it says is in preparation to Rosetta’s end of the mission.
The radio link was effectively the Electrical Support System Processor Unit (ESS) on Rosetta, which was used for communications between the spacecraft and the lander, Philae, which has remained silent since 9 July 2015. ESA says that Rosetta is at a significant distance from the Sun – some 520 million km – and because of this there is lesser solar energy available to the spacecraft.
Rosetta still has a good few weeks worth of tasks remaining and to continue with its operations, it would need all the power it gets and this means there is a need to reduce power consumption by the non-essential payload components on board – the communications unit used for Philae being one of them.
Philae has been silent since July last year – making it a full year of silence. Earlier this year, mission scientists said that the lander was considered to be in a state of eternal hibernation. Despite this ESA allowed ESS to be operational in the hope that Philae may get back in touch, but that hasn’t happened. Although Rosetta has reached altitudes well below 10 km over the surface of Comet 67P/Churyumov-Gerasimenko, however, no signal from the lander was received since July 2015.
The decision to switch off the ESS was taken by the mission manager and was implemented by the Rosetta Mission Operations Centre, in coordination with the DLR Lander Control Center and the Rosetta Science Ground Segment. Despite the Philae incident, the overall mission has been pegged as a great success as the data collected by Rosetta and Philae have improved scientists’ understanding of comets and the role they played in the early universe.