India’s second moon mission, Chandrayaan-2, on Tuesday successfully entered the lunar orbit in a significant milestone.
The lander (Vikram), along with a rover (Pragyan), is expected to touch down on September 7 at 1.55 am.
Chandrayaan-2's 384,000-km journey started on July 22 after the GSLV MkIII-M1 vehicle lifted off from Isro's spaceport at Sriharikota, near Chennai. After 28 days, Isro on Tuesday successfully completed the lunar orbit insertion (LOI) manoeuvre. The duration of manoeuvre took nearly 29 minutes (1,738 seconds), beginning at 9.02 am.
“For 30 minutes, our heart was almost stopped,” said Isro Chairman K Sivan, adding that “tension has now only increased, not reduced”. Prime Minister Narendra Modi, in a tweet, congratulated the Isro team over this “important step in the landmark journey to the moon”.
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 led to complete failure of the mission,” said Sivan.