Face of Nation : India’s second moon mission Chandrayaan 2 successfully completed a major milestone today by breaking away from the Earth’s orbit and entering the moon’s orbit of influence. This is one of the few remaining critical milestones in the mission before the spacecraft attempts a soft-landing in the moon’s South Polar region on 7 September.
The Indian Space Research Organisation announced that the spacecraft completed the Lunar Orbit Insertion (LOI) maneuver today (20 August 2019), in a tweet.
When the moon was at its apogee — its farthest point from the Earth — Chandrayaan 2‘s onboard thrusters fired for 1738 seconds, generating just enough thrust to slow itself down for ‘lunar capture‘. This controlled transfer event — breaking free from the Earth’s orbit of influence and into the moon’s — unfolded over several hours, beginning at 9.02 am IST in on 20 August.
The critical step required the liquid apogee motors to be fired in the opposite direction to the spacecraft’s movement, slowing it down in a what’s known as “retrofiring” of its thrusters. This allowed the spacecraft to come under the influence of the moon’s orbit. With the location of the moon relative to the Earth (and the Earth relative to the Sun) constantly changing, the intersection of Chandrayaan 2’s path with the moon’s was predicted and planned well ahead of time.
Now that the lunar capture, or entry of the spacecraft into lunar orbit, was completed without a hitch or glitch, the two-week (lunar-bound) phase of the mission begins.
This is an important part of the orbiter’s mission: surveilling its year-long home for the first time, ensuring that no damage was caused to its instruments on the journey thus far, and 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 in what the ISRO Chief describes as ‘15 minutes of terror‘.
