Satellites on-board SSLV no longer usable, says Isro

Satellites placed in earth’s orbit by India’s new small satellite launch vehicle (SSLV) cannot be used because of an “anomaly” in their placement, Indian Space Research Organisation (Isro) chairman, S Somanath, said in a video message on Sunday.

The maiden flight of the SSLV-D1 rocket was successful in the early hours on Sunday, Somanath said, but it failed to place its payload of two satellites in the correct orbit at an altitude of 356km from the earth’s surface. The rocket placed them in an elliptical circuit instead of a circular orbit, he said.

The SSLV-D1, India’s smallest launch vehicle (34 metres), was carrying earth observation satellite EOS-02 and AzaadiSAT, a cubesat designed by girl students across India to mark the country’s 75th year of Independence. The cubesat carried 75 microsatellites to conduct scientific experiments. EOS-02 is an imaging microsatellite designed to cater to agriculture and disaster management objectives.

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“The system has a deficiency which we need to look at very carefully and correct it,” Somanath said.

“All the stages performed normal. Both the satellites were injected. But, the orbit achieved was less than expected, which makes it unstable,” India’s state-run space agency said in a statement.

Somanath said the rocket deviated from its path and placed the satellites into 356/76kms low earth orbit due to an “anomaly”.

“The entire vehicle performance was very good in the mission and finally when it reached the orbit at an altitude of 356kms, both EOS-02 and AzaadiSAT were separated. Subsequently, we noticed an anomaly in the placement of the satellites in orbit,” he said.

“The satellites were placed in an elliptical orbit in place of circular orbit. The 356 kms circular orbit was our intended orbit but it could place the satellite in an orbit of 356 /76 kms. As the 76 kms elliptical orbit was the lower most point and closer to the surface of the earth, the satellites placed in such an orbit will not stay for long time due to the atmosphere and will come down. The (two satellites) have already come down from that orbit and are no longer usable”, he said.

An expert panel will analyse the episode and make recommendations to rectify the issue, Somanath said. “ISRO will come back soon with SSLV-D2,” he said.

Scientists had planned to place the satellites into low earth orbits based on ‘launch on demand’ basis. The rocket also marks ISRO’s foray into the launch of small satellites that weigh upto 500 kgs and can be placed into the 500 kms orbit.

The SSLV is capable of launching mini, micro, or nanosatellites between 10kgs and 500kgs to a 500 kms planar orbit. The rocket provides low-cost access to space on demand basis besides offering low turn time, flexibility in accommodating multiple satellites, besides minimal launch infrastructure requirements.

(With PTI inputs)