Chandrayaan-3 countdown starts with craft now 6 days from Moon
BENGALURU: India’s third lunar mission, Chandrayaan-3, is only around six days away from reaching the lunar orbit with another important manoeuvre — that will see Isro slingshot the spacecraft towards Moon — planned between 12am and 1am on August 1. The midnight trans-lunar injection (TLI) manoeuvre is expected to last between 28 and 31 minutes and onboard thrusters of the spacecraft will be fired when the spacecraft is at the closest point to Earth (perigee) and not when at the farthest point (apogee). Why is the slingshot attempted from perigee? At present, the Chandrayaan-3 spacecraft is going around Earth in an elliptical orbit at a velocity ranging between 1km/second and 10. 3km/second. The velocity is highest (10. 3km/second) at perigee and lowest at apogee and while attempting the slingshot, the spacecraft will need to have a high velocity. The other reason is that its angle will have to change to travel towards Moon, which can be added if the operation is carried out at perigee...