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 onboard 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.

Chandrayaan 2 composite orbiting the moon before the lander's separation. Image: ISRO

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 surveilling 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.

Chandrayaan 2 is expected to make its long-awaited powered descent and landing on 7 September at 1.40 am IST in a landing sequence that the ISRO Chief describes as '15 minutes of terror'.

While subsequent events in the mission won't be streamed live, you can catch live updates on the mission on our dedicated Chandrayaan 2 domain, our Twitter page, ISRO's website, or Twitter page.