The Indian Space Research Organisation (ISRO) is scanning for signals from its Chandrayaan-3 mission to the surface of the moon, but so far there have been no signs of the Vikram lander or Pragyan rover waking up from the harsh, two-week-long lunar night. If attempts are unsuccessful, then the hardware has probably succumbed to the moon’s freezing conditions.
“Efforts have been made to establish communication with the Vikram lander and Pragyan rover to ascertain their wake-up condition. As of now, no signals have been received from them. Efforts to establish contact will continue,” ISRO tweeted on 22 September.
The agency launched Chandrayaan-3 in July, with Vikram touching down on the surface on 23 August before releasing the Pragyan rover, which successfully covered around 100 metres on the surface.
Both devices carried out their scientific experiments successfully and Vikram even performed a “hop” manoeuvre, taking off to an altitude of 40 centimetres, moving laterally around the same distance and landing once again. This test was designed to give ISRO engineers valuable data for future landings.
Around two weeks after the mission began – one lunar day – both devices went into “sleep mode” and prepared for sunset and subsequent freezing conditions as low as -238°C that could destroy their electronic components.
The mission was officially over at this point: the scientific payloads were switched off, with all data having been transmitted back to Earth via the lander, whose solar panel was oriented into the best position to start producing power at the next sunrise. In recent days, the moon’s terminator – the line between night and day – has progressed past the landing point and the sun will now rise in angle to a point where the solar panels should be able to begin producing energy.
Both the rover and lander are designed to harvest solar power when available, boot up and resume transmission with Earth, providing their hardware isn’t damaged by the cold. ISRO engineers said they were confident that the rover and lander would boot up once more after another two weeks when the sun rose once again and be able to continue carrying out science and exploring the surface, but stressed that the conditions they would have faced were extremely challenging to certain components.
“This sustained period of cold may have caused issues with the equipment, and it may take longer to warm up than was previously planned, especially if the rover is in the shadow of a boulder,” says Sarah Casewell at the University of Leicester, UK. “The mission was initially only intended to operate for 14 days on the lunar surface, which it did, meeting that goal. So waking up the craft in order to explore the lunar surface further would be a fantastic achievement for the mission team and their engineers.”