India's Chandrayaan 2 has been successfully entered into lunar orbit today, after nearly 30 days of space travel. This was one of the trickiest operations in the mission. A higher-than-expected approach velocity would have bounced off the spacecraft into deep space, while a slow approach would have led to the moon's gravity to pull Chandrayaan 2 and crash it on the lunar surface. The approach velocity had to be just right and the altitude over the moon rather precise. Even a small error would have killed the mission. The process of setting down Chandrayaan 2 on the moon is very complex since it blasted off at a velocity of 39,240 kilometres per hour, which is almost 30 times the speed at which sound travels through air. India's most ambitious space mission to date, Chandrayaan 2 had lifted off from India's spaceport at Sriharikota in Andhra Pradesh on July 22. The lift-off was successful in its second attempt, a week after it was aborted just under an hour from its launch due to a technical glitch. The mission stands out because of its low cost, with just about Rs. 1,000 crore spent - a much smaller price tag compared to similar missions by other countries.