The Pragyan rover and Vikram lander together weigh nearly 1,800 kg.
Chandrayaan-3 has landed on the Moon after "20 minutes of terror" and the Vikram lander and Pragyan rover - carrying six scientific payloads between them - have one lunar day, or 14 Earth days, to gather enough data to satisfy the curiosities of scientists across the world.
This deadline is critical because after a fortnight the solar-powered Pragyan rover - which made its mark on the Moon late last night with ISRO declaring 'India takes a walk on the Moon' - will slow down as this is the extent of the 'sunlight cycle' on the lunar surface.
How Much Time Do Vikram, Pragyan Have On Moon?
Vikram and Pragyan will have 14 days only before night falls on the Moon.
In other words, after 14 Earth days, the Moon will have a night that will last another 14 Earth days. During this time the rover may not be fully functional as there is no solar power and, more importantly, night temperatures can reach a destructive -208 degrees Fahrenheit or - 133 degrees Celsius and the rover, the lander and the payloads will likely have severe trouble operating.
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During this time, the rover will be touch with the lander and that will relay data back to ISRO's mission command centre. ISRO will have no direct link with the rover for this period.
The Landing Date
The legion of scientists at the Indian Space Research Organisation (ISRO) planned Chandrayaan-3's landing date with the same accuracy and precision that helped them land the 1,752 kg Vikram lander (with the Pragyan rover inside) nearly 400,000 km from Earth.
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August 23 was the start of one lunar day/night cycle, which was why that date was picked as the landing date. If Vikram failed to touch down on that day, ISRO had a back-up plan - land on August 24. If there was still no touch down (and the lander was undamaged), ISRO reportedly planned to try again 29 days later - after a full day/night cycle on the moon.
Why The Lunar South Pole?
Chandrayaan-3 is special as no other spacecraft has been able to achieve a soft landing near the Moon's South Pole. This area - far from the equatorial region targeted by other missions, including NASA's crewed Apollo landings - is full of craters and deep trenches.
The findings from the Chandrayaan-3 mission could advance and expand knowledge of lunar water ice, potentially one of the moon's most valuable resources.
So What Happens To The Lunar Modules After Mission Completion?
Neither the Vikram lander nor the Pragyan rover will return to Earth - despite what some Indian lawmakers may believe. And neither will the propulsion module that delivered them.
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On completion of their respective experiments both the lander and rover will remain on the Moon. They will not be functional during the lunar night and while there is no plan to revive them after that period, ISRO is hopeful both will survive the long night and start up again.
The Chandrayaan-3 Mission
The Rs 600 crore-Chandrayaan-3 mission was launched from the Satish Dhawan Space Centre in Andhra Pradesh's Sriharikota on July 14, piggybacking on a Launch Vehicle Mark-III (LVM-3) rocket. The journey to the Moon took 41 days and, significantly, was completed just days after a Russian spacecraft attempting a similar outcome crashed after spinning out of control.