At a news conference on August 20, ISRO Chairman K. Sivan explained how Lander Vikram will arrive on the moon on September 7.
Vikram was delinked on September 2 from the mother orbiter spacecraft, Chandrayaan 2. It was gradually slotted into a 35 km x 101 km orbit around the moon.
As it went around the moon, Vikram’s sharp cameras were scanning and taking photos of the lunar surface and the region where it should get down.
According to ISRO’s planning, about an hour after the midnight of September 6-7, Vikram enters a powered descent mode. It starts lowering itself around 1.30 a.m. Its four engines switch off and the central engine alone will work. The speed will be reduced or adjusted from 1.6 km per second. These are apparently the last 15 nightmarish minutes for the mission team.
Landing venue
ISRO has chosen a flattish region between two craters for the arrival of Vikram: Manzimus C and Simpelius N.
On the lunar globe, it would be 70.9 degrees south latitude and 22.7 degrees east longitude. Reports say it would be about 600 km from the south pole and the southernmost visit of any spacecraft. All other landers chose the moon's safe equatorial belt, while China is currently probing around 45 degrees south on the other face of moon.
As Vikram hovers over the appointed spot, the scores of sensors on it tell it its height from the surface, the pitfalls below, the slopes and the rocks that may topple it on landing. If the spot is unfit, the lander has just a few seconds to rise and flit to the next back-up slot nearby.
Once it lands, rover Pragyan sitting inside must wait for two hours for the slow moon dust to settle. A ramp unfolds and the rover's solar panel gets deployed. After 3 hours and 15 minutes, the six-wheeled rover starts moving out, taking about 45 minutes to touch down on the moon.
According to ISRO, the two will take pictures of each other to beam them to earth. The rover can talk only with the lander.
What the rover may find is another story.
