'Getting Ever Closer To The Moon': Chandrayaan-3 Undergoes Orbit Reduction Manoeuvre. Know What's Next

Chandrayaan-3 is now in an orbit of 174 kilometres × 1437 kilometres. A retro-firing of engines was conducted to allow Chandrayaan-3 to perform its third lunar-bound orbit manoeuvre.

Chandrayaan-3 performed its third lunar-bound orbit manoeuvre on August 9, 2023. The next orbit reduction manoeuvre will take place on August 14, 2023. ( Image Source :Twitter/@ISRO )

Chandrayaan-3 successfully underwent a planned orbit reduction manoeuvre on Wednesday, August 9, 2023, bringing it closer to the Moon. In order to perform this operation, a retro-firing of engines was conducted. Now, Chandrayaan-3 is in an orbit of 174 kilometres × 1437 kilometres, the Indian Space Research Organisation (ISRO) said in a mission update. This was Chandrayaan-3's third lunar-bound orbit manoeuvre. 

Retro-firing allows a spacecraft to be pushed forward because its engines are burnt in a direction opposite to the way the spacecraft was fired. 

After Chandrayaan-3 successfully performed its third lunar-bound orbit manoeuvre, the spacecraft's official X (formally Twitter) account wrote: "Getting ever closer to the Moon!"

Getting ever closer to the moon!

The #Chandrayaan3 spacecraft successfully underwent a planned orbit reduction maneuver. The retrofiring of engines brought it closer to the Moon's surface, now to 174 km x 1437 km.

The next operation to further reduce the orbit is scheduled for… pic.twitter.com/vCTnVIMZ4R

— LVM3-M4/CHANDRAYAAN-3 MISSION (@chandrayaan_3) August 9, 2023

The next orbit reduction manoeuvre will take place on August 14, 2023, between 11:30 am to 12:30 am IST. 

On August 6, ISRO shared stunning views of the Moon captured by Chandrayaan-3. 

The Moon, as viewed by #Chandrayaan3 spacecraft during Lunar Orbit Insertion (LOI) on August 5, 2023.#ISRO pic.twitter.com/xQtVyLTu0c

— LVM3-M4/CHANDRAYAAN-3 MISSION (@chandrayaan_3) August 6, 2023

The spacecraft entered lunar orbit on August 5, and the next day, it performed its second lunar-bound orbit manoeuvre. Lunar orbit insertion of Chandrayaan-3 took place after the ISRO Telemetry, Tracking and Command Network (ISTRAC) commanded a retro-firing at the perilune. The perilune is the point in the lunar orbit at which the spacecraft is closest to the Moon. At perilune, Chandrayaan-3 performed a manoeuvre that allowed it to inject itself into the lunar orbit.

On August 4, Chandrayaan-3 covered two-thirds of the distance between Earth and Moon. On August 1, Chandrayaan-3 entered the Moon's sphere of influence, after successfully completing an orbit-raising manoeuvre or a perigee burn. A perigee burn is one which allows a spacecraft to raise its orbit.

In the early hours of August 1, Chandrayaan-3 completed its orbit around Earth following which it was injected into translunar orbit.

The Chandrayaan-3 spacecraft's voyage towards the Moon began after ISRO's largest and heaviest rocket, the Launch Vehicle Mark III (LVM3), carried India's third lunar exploration mission from Satish Dhawan Space Centre, Sriharikota, Andhra Pradesh. 

ISRO aims to land Chandrayaan-3's lander softly on the Moon's south pole. If this is achieved, India will become the fourth nation to complete the soft landing of a spacecraft on the Moon, and also the first country to land a spacecraft on the Moon's south pole.

Chandrayaan-3 has three phases: the Earth-centric phase, the lunar transfer phase, and the Moon-centric phase. 

The Earth-centric phase, or Phase-1, involves the pre-launch phase; the launch and ascent phase; and the Earth-bound manoeuvre phase, which will help the Chandrayaan-3 spacecraft change its directions. 

The lunar transfer phase includes the transfer trajectory phase, as part of which Chandrayaan-3 chose the path that will lead it towards the lunar orbit. 

The Moon-centric phase involves all the steps from lunar orbit insertion to landing. 

The spacecraft consists of a lander, a rover and a propulsion module. The rover is fitted inside the lander, and together, they are called the lander module. The objectives of the mission are to demonstrate soft landing on the lunar surface, and roving on the lunar terrain, conduct in-situ scientific experiments, and develop and demonstrate new technologies required for interplanetary missions. 

Chandrayaan-3 was inserted into Earth orbit a few minutes after launch. After this, the spacecraft was separated from the launch vehicle. The propulsion module is carrying the lander module to a lunar circular orbit whose size is 100 × 100 square kilometres. After this, the propulsion module and the lander module will separate. 

The mission life of the propulsion module is three to six months. It weighs 2,148 kilograms, and has a power generation capacity of 758 Watts. 

Chandrayaan-3 is expected to reach the lunar surface on August 23 or 24, 2023.