The ISRO Chairman expressed optimism that as the sun rises over the Shivshakti Point, where the lander and rover are positioned, the equipment will be reactivated.
As a new lunar dawn approaches, the Indian Space Research Organisation (ISRO) is gearing up for an ambitious endeavor to reactivate the Chandrayaan-3’s Vikram lander and Pragyan rover, which have been in ‘sleep’ mode for two weeks to assess their survival in the frigid lunar night.
The anticipated reawakening of these modules on Thursday and Friday presents the opportunity for an additional extension beyond what has already been a highly successful mission, according to ISRO scientists.
S. Somanath, Chairman of ISRO, expressed hope that as the sun rises over the Shivshakti Point, where the lander and rover are stationed, the equipment will spring back to life. The teams are scheduled to initiate the revival process on September 21 and 22, coinciding with the lunar dawn. Somanath remarked, ‘Our optimism is centered on witnessing the equipment spring to life on September 22.’
ISRO officials noted that prior to placing the equipment on board Vikram and Pragyan into sleep mode, which was implemented in phases starting on September 2, the batteries, powered by sunlight, were fully charged, and solar panels were oriented to receive light at dawn.
Should the on-board instruments withstand the extreme lunar night temperatures, which can plummet to around -200°C, they may reawaken and continue gathering data from the lunar surface for an additional 14 days.
In an ideal scenario, once commands are transmitted to the lander and rover to revive their systems, the rover will recommence its exploration of the lunar surface, and the instruments on the lander will resume collecting data.
On Thursday, when the sunlight becomes sufficiently intense at the landing site to power the instruments, teams from ISRO Telemetry, Tracking, and Command Network (ISTRAC) will commence the process of sending commands to reactivate the instruments. If the devices respond and recharge themselves, the mission could enjoy an extended lease of life, enabling scientists to acquire more valuable data.
However, this endeavor may not be without its challenges. Lunar surface temperatures can plummet as low as -200°C, and in polar regions, they can drop even further to around -250°C.
While prior spacecraft, such as China’s Chang’e 4 lander and rover in 2019, successfully endured similarly low temperatures and reactivated, these craft were equipped with radioisotope heating units (RHU). These units maintain a suitable temperature for device functionality by utilizing the decay of plutonium-238 to generate heat, thus safeguarding the equipment from the harsh external cold. Neither the Chandrayaan-3 lander nor the rover is equipped with these heating devices.
A senior ISRO official stated, ‘If we had RHUs, our confidence in revival would be higher than hope.’
ISRO scientists have confirmed that efforts are underway to develop RHUs for extended interplanetary missions, ensuring that equipment remains operational in prolonged, frigid space conditions. The technology demonstration for these devices is expected to occur in the near future, according to ISRO officials.