Chandrayaan-3’s Vikram lander and Pragyan rover have been put in ‘sleep mode’ and ‘will fall asleep next to each other once the solar power is depleted and the battery is drained’ ISRO said.
India’s space agency added that it hoped the duo would reawaken ‘around 22 September’ when the next lunar day starts, as the lander and rover need sunlight to charge their batteries.
Vikram and Pragyan historically touched down on the Moon’s little-explored south pole on 23 August, making India the first nation to do so in a space dominated by the West.
India joined an elite club of countries to achieve a soft landing on the Moon, after the US, the former Soviet Union and China.
The Indian space agency has been providing regular updates on the lander and the rover’s movements and findings and sharing images taken by them.
In its latest update on Monday morning, ISRO said Vikram had ‘soft-landed on the Moon again!’
After the Chandrayaan-3 mission’s lander was ‘commanded to fire its engines, it rose up by about 40cm [16 inches] and landed at a distance of 30-40cm’ ISRO noted.
The lander performed this short ‘hop’ to move closer to the already sleeping Pragyan rover. This hop may be seen as a test for a future sample return missions that would need to launch from the moon’s surface
Chandrayaan-3’s landing had been carefully planned to coincide with the start of the lunar day, which equals a little over four weeks on Earth. ISRO had said this would allow the lander and the rover 14 days of sunlight to charge their batteries. Vikram and Pragyan have both gone beyond their mission objectives and have completed all their assignments.
Initially, ISRO had said that once night fell on the moon, the lander and the rover would stop working. Scientists say it is possiblet, however, that they will come back to life when the next lunar day starts.
For instance, China’s Chang’e4 lander and Yutu2 rover woke up several times with the lunar sunrise.
So, ISRO is hoping that Vikram and Pragyan would also wake up when the new day breaks, so their batteries have been fully charged, all scientific instruments have been turned off and they are now ‘safely parked in sleep mode.’
‘Sunlight falls on a particular spot on the surface depending on its location, and the Sun goes down in orientation near the pole sooner, which means that the lander and the rover would not get sunlight for long,’ a former ISRO official said.
‘The lander and the rover have been prepped for when the day breaks again. So they are parked in the right spot and with right solar orientation. When the Sun rises next, the solar panels will face in its direction so they are able to absorb radiation and generate power and feed the system to bring it back to life,’ he said.
The rover may be at a particular disadvantage owing to its size and could be in the shadows of the pole region which has lots of craters with elevated rims.
The evening Sun going down can lengthen these shadows further, which can put the rover more in the dark.
Expectations are muted.
‘We are hopeful, but you can never tell. Their batteries are not designed to operate or for storage in the temperatures that can go down to -200C to -250C.’
‘The battery is fully charged. The solar panel is oriented to receive the light at the next sunrise. The receiver is kept on. Hoping for a successful awakening for another set of assignments!’ ISRO posted on X, formerly called Twitter.
‘Else, it will forever stay there as India’s lunar ambassador.’
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