Pragyan: Chandrayaan-3: New lunar soil knowledge, other takeaways expected; Isro waits to hear from Vikram & Pragyan

BENGALURU: As Isro burns the midnight oil on Earth, waiting to hear again from Chandrayaan-3 lander (Vikram) and rover (Pragyan), principal investigators of instruments on the two have begun sifting through data for new findings.
Among many things the global scientific community is expected to learn from Vikram and Pragyan’s work before they went to sleep is new knowledge about the lunar soil, which will be useful for future missions, including ambitious projects aiming to send humans back to Moon.
“It would have been easy if there was a way we could know if they would wake up, but we have to wait and see how systems behave after Sunrise,” Isro chairman S Somanath said.
With Sunrise on Moon expected early Wednesday, the Sun elevation angle will be at 0° early in the day and reach a maximum of around 13° angle by the end of the day.
“The optimal Sun elevation angle for systems to work would be 6° to 9°. But the temperature has to rise above a certain threshold. For the wake up, we need power generation and temperature on the elements on Vikram and Pragyan to meet certain criteria. We should know something by September 21 or 22. If they wake up, it’ll wake up during this time,” M Sankaran, director, UR Rao Satellite Centre, the Chandrayaan-3 lead centre, told TOI.
Multiple Isro scientists TOI spoke with reiterated that Vikram and Pragyan waking would be a bonus and that the data the two have sent when they were awake is expected to give new information given that all earlier in situ experiments were carried out in the equatorial region of the Moon.
“Lot of data has been collected but outcomes will take several months, even a couple of years. There is anticipation that our data would lead to some new things. And if systems wake up again, there’ll be more data, which is good,” Sankaran added.
Physical Research Laboratory (PRL) director Anil Bharadwaj said teams were looking into datasets from instruments studying the surface, seismicity, temperature, elements, profile of temperature beneath the surface, regolith (topsoil) properties such as how fluffy, loose or grainy it is.
“There are many parametres being studied. Our observations have the potential to give new information about the topsoil. We can very clearly see rover movement paths being created, images of the vicinity of the landing site and rover movement site show grooves of the rover are about a centimetre, the lander legs going inside, suggesting loose soil. Soil will become compact as one goes deeper,” he said.
“…That part we need to understand. How much is topsoil (regolith) and where it gets compact. There are previous conjectures about the features, how they are able to retain signatures despite having loose soil. There’s information built into observations that are carried out, we have to look at multiple parametres, no one thing will tell us these things. These studies will be carried out,” he added.
As reported earlier by TOI, Chandrayaan-3 instruments have measured the temperature — which varies in the range of -10°Celsius to 60°Celsius, depending on the depth — and confirmed the presence of Sulphur, which indicates a volcanic past.
Isro Space Application Centre (SAC) director Nilesh M Desai said: “One of the things we had targeted while planning the mission was whether frozen ice could be found on crater rims. To know more we need to study the rover data. It depends on where the rover has moved, what kind of data it has found when it was close to a crater.”