Chandrayaan-3: Will rover Pragyaan and lander Vikram wake up today?

"Vikram Lander and Pragyan Rover have been in deep sleep for almost two weeks now. It is almost like taking out something from the freezer and then trying to use it. The temperatures would have gone beyond -150 degrees Celsius,” Nair told news agency ANI.

"As the temperature rises above minus 10 degrees, a wake-up call will go and Vikram and Pragyan will rise from their sleep," the minister said.

He added that a communication circuit - with the lander and rover - has to be activated. The communication circuit is called the wake-up circuit. "It will work when the temperature rises to minus 10 degrees. Now team ISRO and everyone connected to the mission are waiting for the temperature to rise on the moon," the minister said.

The lander has already proved that it can soft land on the lunar surface and even "hop" on it. But restarting itself is another important experiment that ISRO aims to carry out with the Chandrayaan-3 mission's lander and rover. If ISRO successfully manages to revive Pragyan and Vikram, India will become the first country to do so in space history.

Jitendra Singh told Parliament on Thursday that officials are waiting for the wake-up call to get activated and Vikram and Pragyan to respond to that alarm. "Once they do, the communication from the earth will begin and we will be the first in the world to have accomplished this," he said.

Lander Vikram and Rover are currently parked next to each other on the South Pole of the Moon.

A successful revival would mean that that its scientific equipment can withstand extreme conditions, and still function. The Chandrayaan-3 mission was originally designed to operate for one lunar day or 14 days on Earth. Once the sun sets on the Moon, the temperature drops to -200℃, freezing everything on there. This threatens damage to parts of the lander and the rover. Therefore, a re-start attempt depends on whether the equipment can survive the extreme conditions on the South Pole.

"At this temperature, no plastic material, no carbon power material or no electronics can survive. They will crack. But I'm hopeful that ISRO must have done a lot of thermal management thing,” former ISRO scientist Tapan Mishra told ANI in Kolkata.

Meanwhile, Nair was quoted as saying, "The solar heat will warm up the instruments and also recharge the batteries. If both these conditions are successfully met, there is a fairly good chance that the system will be operational again."

If restarted successfully, both the lander and rover may then collect more observations. "Once it comes to operation, it is quite possible that we can move around for some distance over the next 14 days and collect adequate data, more data on the surface conditions on the Moon near the South Pole,” Nair said.

But even if it does not restart, the experiment will add to a rich set of observations and learnings from the Moon, considering that Chandrayaan-3 is the first and only spacecraft to land on the South Pole, News 18 reported.

Mishra asserted that if it survives one night then it will survive many more lunar nights. "...if it happens, then we will be in a league that can operate the lunar lander, rover, even throughout the year. If it survives one lunar night, I'm sure it will survive many more lunar nights and it may probably operate from 6 months to one year. That will be a great thing,” he said.

India's Vikram lander touched down near the south pole of the moon on August 23, successfully completing one of the Chandrayaan-3 mission's main objectives of soft landing on the lunar surface. This made India the first country to soft-land a spacecraft on the lunar south pole.

The lander and the rover went into sleep mode on the morning of September 4. "The Chandrayaan-3 landed successfully and it worked for almost 14 days. It was designed to work for 14 days (on the moon). Its life period was only 14 days because the moon's temperature falls down to (-) 250 degrees during the (lunar) nighttime. So it worked during the sun hours or daytime and during that it had already given all the data (it was supposed to)," said Bhubaneswar-based space scientist Suvendu Patnayak.

Before calling it a day, the ISRO had fired its engines, elevated the lander by about 40cm and tried to make it land safely at a distance of about 30-40 cm away. The "hop" experiment by the scientists was succesfull.

Besides, the two payloads — ChaSTE and ILSA — were folded back by deploying the ramp, and re-deployed successfully after the experiment. They were tested again at the new location and once the data was received at the Earth, the payloads were switched off.

Lander receivers were kept 'on' to keep the communication. Even though it was not planned, the demonstration would help ISRO in future moon missions — especially to collect rock/soil samples and return them to Earth.