When India went to sleep on Friday night, Isro's rocket engines continued to circle the earth about 150 km from the satellite Cartosat-2s, it launched hours earlier. The fourth stage of PSLVC38, carrying two science instruments, was reignited thrice after it lobbed 31 satellites into orbit on Friday morning. The stage flew to 10 different orbits, after complex manoeuvre, for several hours as the instruments collected valuable atmospheric data that will guide Isro to launch future satellites into multiple orbits in a single flight.
The fourth stage was actively circling the earth till midnight, almost 12 hours after the rocket placed satellites in the orbit.
The rocket was launched from the first launch pad at Satish Dhawan Space Centre at 9.29 am. It carried 712 kg weighing earth observation satellite Cartosat-2s and 30 other nano-satellites including 29 from 14 countries. About 16 minutes after takeoff, the rocket's fourth stage placed the satellites into orbit. Usually , the engine is deactivated after the successful ejection of satellites. But this time, the mission was far from over. The fourth stage, containing two liquid apogee motor engines, went to on perform a technique involving simple experiments through complex manoeuvring across 10 orbits.
The space agency had to limit its payload weight as the long duration experiment required resources from the rocket including its fuel.