A senior official closely associated with the Chandrayaan 2 mission said the Indian Space Research Organisation (ISRO) has likely lost contact, and therefore access to, the Vikram lander and the Pragyan rover housed inside it, signalling that the much-anticipated mission has ended as a partial failure, or partial success.
“There is no communication with the lander. It is as good as lost. There is no hope; it is very, very difficult to reestablish contact,” the official said.
Former ISRO Chairman G. Madhavan Nair chose to describe the outcome as a glass half-full, rather 95% full, saying on Saturday that Chandrayaan 2 has achieved “95 per cent” of its objectives notwithstanding the lander’s unsuccessful bid to touchdown on the lunar surface.
Nair, former secretary of the Department of Space, former chairman of the space commission and a member of the Bharatiya Janata Party in Kerala since last year, said the orbiter is healthy and functioning normally in lunar orbit.
Chandrayaan 2 had multiple objectives; the lander’s soft-landing was one of them, albeit a particularly tricky one that was always going to be hard to pull off.
“I think we need not worry too much,” Nair told PTI after the lander, christened Vikram, lost contact with ground stations during its autonomous descent between 1:30 am and 2:30 am on Saturday.
He added that the orbiter is functional and that it “should do an excellent job of mapping” the lunar surface – a task that ISRO’s previous major lunar mission, Chandrayaan 1, had commenced a decade ago.
Chandrayaan 2 is in fact a follow-on mission to Chandrayaan 1, but much more sophisticated in scope and ability. The 2.3-tonne orbiter was designed with a mission life of one year and carries eight scientific payloads for mapping the lunar surface and studying the satellite’s outer atmosphere. To this end, the payloads are fit with remote-sensing instruments. The orbiter is in a circular orbit around the Moon at an altitude of 100 km.
Also read | Why Chandrayaan 2 Was a Success Well Before ‘Vikram’ Got to the Moon
According to ISRO, the lander carried three scientific payloads to conduct surface and subsurface science experiments while the rover carried two instruments to enhance our understanding of the lunar surface.
Nair said the lander’s loss of contact was highly disappointing and that he never expected such a scenario: “It’s disappointing for all of us.” According to him, the entire mission was pulled off with precision until the autonomous descent failed.
“Half of us were keeping our fingers crossed because there are several instruments and thrusters [that] will have to work very precisely, only then will the final objective [have been] achieved,” he said. “If you start listing, there are at least ten points where it could have gone wrong. What has really gone wrong is difficult to predict now.”
He ultimately expressed confidence that ISRO would be able to identify what went wrong. Indeed, journalists around the country as well as observers wait with bated breath for updates for ISRO, which – in traditional fashion – has stayed mum.
While live updates from the mission control centre in Bengaluru last night suggested an issue with the lander’s engine (based on Doppler curve data), Nair said there could be any number of reasons, including sensor failure, onboard software anomaly and thrust deviation.
“Vikram lander descent was as planned and normal performance was observed up to an altitude of 2.1 km. Subsequently, the communication from the lander to ground-stations was lost,” K. Sivan, the incumbent ISRO chief, had said earlier, adding that he and his team were still analysing telemetry data.