Chandrayaan-2 now 2 days away from Lander separation

The much-awaited separation of the Lander, Vikram from the Chandrayaan-2 Moon mission is now just two days away. On Friday, the fourth lunar-bound orbit-lowering manoeuvre was successfully performed on the spacecraft.

The manoeuvre began at 6.18 pm as planned using the propulsion system onboard the Orbiter-Lander-Rover composite of Chandrayaan-2, India's most ambitious Moon mission till date. “The duration of the manoeuvre was 1,155 seconds (about 19.5 minutes),” the Indian Space Research Organisation (Isro) announced.

The new orbit achieved is 124 km X 164 km. The space agency certified that all spacecraft parameters are normal. The next lunar-bound orbit manoeuvre has been scheduled between 6 pm and 7 pm on September 1.

Once the next manoeuvre places the spacecraft in a 100 km X 100 km orbit, the Orbiter will remain there for the rest of its life. Isro officials have indicated that this could be well over a year. During this period, it will relay high-resolution images of the lunar surface to Isro's Earth stations.

Lander separation

The much-awaited separation of the Lander, Vikram from the Orbiter will be conducted on September 2, before it prepares for the final Moon landing on September 7. Although the mission team will shift its focus to the Lander thereafter, the Orbiter will ensure the safety of the landing site.

Using its onboard Orbiter High-Resolution Camera (OHRC), the Lander will identify a landing site that is flat enough with an angle not exceeding 12 degrees. Anything beyond this angle could jeopardise the entire mission and the Lander could topple.

OHRC, through a mosaic of high-resolution images, will also detect any craters or boulders on the landing site even before the big separation. The images it captures, taken from two different look angles, will serve two purposes.

The space agency explains: “Firstly, they are used to generate DEMs (Digital Elevation Models) of the landing site. Secondly, they are used for scientific research, post-lander separation.” OHRC's images will be captured over the course of two orbits, covering an area of 12 km X 3 km with a ground resolution of 0.32 metres.