Chandrayaan 2 composite orbiting the moon before the lander's separation

SRIHARIKOTA: India's second moon mission Chandrayaan-2 is expected to carry out its final orbit-lowering manoeuvre around the moon this evening. The lunar-bound manoeuvre is planned between 6-7 am on 30 August using the spacecraft's on-board propulsion system. This fourth and final manoeuvre will move Chandrayaan 2 from its current 179 x 1411 km (nearest x farthest distance) elliptical orbit to a near-circular orbit of 126 x 168 km.

The Chandrayaan 2 composite has carried out three successful in-orbit manoeuvres since it entered lunar orbit — all in an attempt to lower its altitude in preparation for landing. If successful, the final manoeuvre today will put the spacecraft on a circular path that passes over the lunar poles at a distance of about 100 km from the surface. Entering this circular orbit is the mission's final milestone before the Vikram lander separates from the orbiter to make its planned soft-landing on the moon's surface on 7 September.

The approximately 100 x 100 km circular orbit is close enough for the Vikram lander, which is currently bound to the orbiter in a 'composite', to separate. The separation and landing sequences are planned for 2 September and 7 September at 1.40 am, respectively. Between these two important days, the first maps of the landing site will be created (planned for 3 and 4 September) to ensure the landing site is as safe as previously thought to make a soft-landing. This is a crucial step in the mission since ISRO's mission engineers won't be operating the spacecraft remotely. The orbiter will also be surveying its year-long home for the first time, ensuring that no damage was caused to its instruments on the journey thus far, and conducting a thorough examination of the Vikram lander's landing site at the moon's South Polar region.