They said they would keep trying until the end of the lunar day.

Just over 14 Earth days pass between a day and a night on the Moon.

Isro reported on Friday that it had not been able to contact the lander and rover since the new lunar day began.

Vikram, carrying the Pragyaan rover, landed near the Moon’s little-explored south pole in August. After gathering data and images for two weeks, they went into ‘sleep mode’ at lunar nightfall.

When the lunar Sun rose around 22 September, the Indian Space Research Organisation (Isro) hoped the batteries would recharge and the modules would reawaken.

“Effects to establish communication with the Vikram lander and Pragyaan rover will continue,” Isro posted on Friday. Since then, there has been no official update.

Former Isro chief AS Kiran Kumar told the on Monday morning that “chances of reawakening are dwindling.”.

In addition, temperatures near the lunar south pole are known to plunge to -200C to -250C (-328F to -418F) at night, making the lander and rover unlikely to survive the frigid temperatures.

There is no way to know whether the lander is alive unless the transmitter on the lander comes on. It must tell us that it is alive. Even if all the other sub-systems work, we have no way of knowing it.

In addition, an Isro spokesman said efforts were continuing to contact the lander and rover.