Pragyan was the rover of Chandrayaan-2, a lunar mission developed by the Indian Space Research Organisation (ISRO), launched in July 2019. Pragyan was destroyed along with its lander, Vikram, when it crash-landed on the Moon in September 2019 and never got the chance to deploy.
The expected operating time of the Pragyan rover was one lunar day or around 14 Earth days, as its electronics, not designed to endure the frigid lunar night. Let’s try to know why?
Before diving into the actual topic, you should understand some basic facts about Moon.
The circumference of the earth is 40,075 KM, and the rotation speed is 1674 km/h. Hence, it takes 23.939 hours(40075 divided by 1674) to complete one full turn on its axis.
Now, if we consider the same for the Moon, it’s circumference is 10,921 km, and the rotation speed is 0.004627 km/s so, it takes 2,360,276.637 seconds (10921 divided by 0.004627) which is, 656 hours or 27.32 days.
It means the Moon takes 27.3 days to complete one Earth day.
Considering the above facts, we should understand that one day on earth is equal to 27 days on the Moon. As per the reports stated by ISRO, the rover receives its operating power from solar energy which can be obtained only in the daytime. Nighttime in it is extremely cold and reaches up to 180 degrees. Our scientists have designed the lifespan of the rover according to the daytime which is 14 days on the moon.https://en.wikipedia.org/wiki/Pragyan_(rover)
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