The Indian Space Research Organisation (ISRO) is set to conduct Trans Lunar Injection (TLI) tonight on Chandrayaan-3. The spacecraft — has been flying in the space vacuum for almost 15 days — will be put on its course to the moon after the TLI.
ISRO has scheduled this crucial process to take place at midnight, between 12 am and 1 am on August 1. According to an India Today report, this is expected to last for about 28 to 31 minutes, during which the engines — on Propulsion Module — of the spacecraft will rejuvenate to amp up the velocity.
What is Trans Lunar Injection?
TLI is a propulsive manoeuver which helps to set a spacecraft on a trajectory that will put it on its course to the Moon. Generally, this process is performed by a chemical rocket engine and it involves a certain burn, this increases the speed of the spacecraft.
The increased speed changes its orbit from a low, circular Earth orbit to a highly eccentric orbit. The TLI burn — in a specific way — is sized and timed to target the Moon perfectly.
The TLI burn is timed because it ensures that the spacecraft reaches near apogee (closest point) as the Moon approaches. Following which, the spacecraft will enter the Moon’s orbit, making a hyperbolic lunar swingby.
Chandrayaan-3 was successfully launched on July 14 from the Satish Dhawan Space Centre in Sriharikota. Since the launch, the mission has executed five orbit-raising manoeuvres successfully. This scheduled TLI is a crucial point in this journey to Moon.
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According to reports, upon completing the TLI successfully, Chandrayaan-3 will commence on its lunar transfer arc, approximating an elliptical trajectory about the Earth with an apogee near the radius of the Moon’s orbit.
Following the completion of a series of complex manoeuvers, the spacecraft is expected to reach the Moon’s orbit. And once it enters the orbit, the mission will be in its moon-centric phase. This will be followed by a lineup of various important events, including the lander’s separation, set of deboost manoeuvers and lastly the drop phase for a soft landing on the Moon’s surface.
The scientific instruments designed to study several aspects of the Moon’s surface are being carried by the Chandrayaan-3 spacecraft. These aspects include lunar seismicity, lunar regolith’s thermophysical characteristics, lunar surface plasma environment, and the elemental composition in the landing site area on the Moon, reports.
The total cost of the Chandrayaan-3 mission is Rs 615 crores, which is notably lower than the cost — Rs 978 crores — of Chandrayaan-2.
The mission is a landmark in the nation’s journey of space exploration. The spacecraft, upon landing, will be operating for one lunar day which is nearly 14 Earth days.
The first mission, Chandrayaan-1, was launched in 2008 and successfully entered lunar orbit. Chandrayaan-2, launched in 2019, also entered lunar orbit successfully but encountered a setback when its lander deviated from its intended trajectory and crash-landed on the moon’s surface due to a software glitch.
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The third lunar exploration by ISRO, Chandrayaan-3 comprises a Lander and Rover configuration and will be launched by the LVM3 (Launch Vehicle Mark 3) from the Satish Dhawan Space Centre (SDSC) SHAR in Sriharikota.