India’s Chandrayaan-3 gets more closer to the moon

The Indian Space Research Organisation (ISRO) on Wednesday said the Chandrayaan-3 spacecraft has moved closer to the moon surface with the reduction in its orbit for a second time.

The Indian space agency said: "Chandrayaan-3's orbit is reduced to 174 km x 1437 km following a manuevre performed today. The next operation is scheduled for August 14, 2023, between 11:30 and 12:30 Hrs. IST."

The spacecraft was brought down further – reduction in orbit - by firing its onboard engines to 174 km x 1437 km from 170 km x 4313 km. The orbit is reduced so that the main purpose of the Chandrayaan-3 mission is sought to be achieved, that is, soft landing of the lander on the moon.

The orbit reduction is done by retro firing (backward propulsion) of the on-board motors to slow down the spacecraft. The third orbit reduction operation will be on August 14 between 11.30 a.m. and 12.30 p.m.

During this process, the speed of the spacecraft is reduced by firing its motors in the opposite direction. The fourth orbit reduction process is expected to be done on August 16.

On August 6, the first lunar orbit reduction was carried out. The spacecraft comprises a propulsion module (weighing 2,148 kg), a lander (1,723.89 kg) and a rover (26 kg).

Sometime after the fourth orbit reduction activity, the lander will get separated from the propulsion module a couple of days and later expected to make a soft-landing near the South Pole of the moon on August 23 at 5.47 p.m. The lander will descend to the moon from a height of about 100 km from the moon's surface. The soft landing is a tricky issue as it involves a series of complex manoeuvres consisting of rough and fine braking.

Imaging of the landing site region prior to landing will be done for finding safe and hazard-free zones. Subsequent to the soft landing, the six-wheeled rover will roll out and carry out experiments on the lunar surface for a period of one lunar day which is equal to 14 earth days.

The Chandrayaan-3 was put into orbit on July 14 in a copybook style by India's heavy lift rocket LVM3. The spacecraft completed orbiting around the earth and headed towards the moon on August 1. On that day a successful perigee-firing performed at ISTRAC, the ISRO had injected the spacecraft into the translunar orbit.