SRIHARIKOTA: Indian Space Research Organisation on Monday successfully placed advanced weather satelliteSCATSAT-1 in orbit, around 17 minutes after a Polar Satellite Launch Vehicle (PSLV-C35) carrying eight satellites took off from Satish Dhawan Space Centre in Sriharikota. This is Isro’s longest ever launch mission.
The mission spanning over over two hours and 15 minutes is still underway with the rocket expected to fly into a different orbit to place other seven satellites. It will also be the first time that satellites are being placed in two different orbits with a single rocket.
PSLV-C35 lifted off from Satish Dhawan Space Centre at 9.12am, as scheduled.SCATSAT-1, the main payload of PSLV in its 37th flight, was placed in the polar sun synchronous orbit at an altitude of about 730km.
SCATSAT-1, which will provide weather forecast including cyclone detection and tracking, will succeed the now defunct Oceansat-2 satellite launched in 2009.
According to Isro scientists, PSLV-C35 is expected to coast a little farther before its fourth-stage engine is ignited and shut down, for about 20 seconds, after an hour post the first satellite injection. This will provide the rocket the necessary thrust to coast into the polar orbit at an altitude of 689km.
The challenge in the launch is igniting and shutting down the fourth-stage engine, called multiple burn technology, twice within a short span of time in a cold and low-gravity environment and letting it coast further. Isro demonstrated the technology in its two previous PSLV launches – PSLV-C34 in June 2016 and PSLV-C29 in December 2015. But the trickiest part is also to cool down the engine between two restarts and protect the rocket and satellites from the heat generated when the engine is operational.
Placing satellites in different orbits will also facilitate launching more such commercial satellites in the future.