Indian space makes a splash

Retrieval of satellite demonstrates re-entry capability

CHENNAI: It was a perfect fall that marked the rise of India into an orbit of excellence in space science.

A 550-kg satellite that India’s own rocket launched into orbit 12 days ago, was successfully brought back to earth and retrieved on Monday after deft manoeuvres lasting 64 minutes.

The Space capsule Recovery Experiment (SRE-1), as the satellite is called, was launched by PSLV-C7 from the Satish Dhawan Space Centre (SDSC) in Sriharikota on January 10. It splashed down at 9.46 am in the Bay of Bengal after it was brought down from its 637-km high orbit in space.

With this, the Indian Space Research Organisation (ISRO) has demonstrated its skill in re-entry technology, vital for future space projects like re-usable launch vehicles and manned missions. The others to master the technology are the US, China, Japan and the European Space Agency.

The wait for the capsule started on Monday, after ISRO scientists in Bangalore issued commands to change the SRE’s orbit from a circular one to an elliptical one on January 19. At 8.42 am on Monday, scientists started the re-orientation of the satellite before firing the onboard rocket motors to push it back to the atmosphere.

As the SRE made its re-entry, the indigenously developed thermal protection system helped the capsule withstand the 2,100 degrees Celsius heat as it entered the dense atmosphere with a velocity of 29,000 km per hour.

ISRO chairman Madhavan Nair and his team of scientists waited at Sriharikota, 140 km away from where SRE would splash in the sea 12 minutes later. At a safe distance from the splash point, two Navy ships and a Coast Guard vessel with scientists and divers waited while a chopper and a droner aircraft hovered around.

By the time SRE descended to an altitude of 5 km, the aerodynamic breaking had reduced its velocity to 363 km/hr, which was further brought down to 47 km/hr by two parachutes. The satellite finally came down at a velocity of 43 km/ hr. A floatation device was immediately triggered to keep the capsule floating before the ships recovered it and brought to Chennai and later to Sriharikota.

“I never had any doubt about SRE’s safe return and retrieval. Only that I could not witness the splashdown,” SRE project director A Subramanian told DNA.