ISRO says satellites injected by SSLV 'no longer usable'; 'committee will analyse'

India's first Small Satellite Launch Vehicle (SSLV) successfully injected both satellites after separation, but the orbit achieved was lower than expected, making it unstable, according to ISRO. At 9.18 a.m. on August 7, the Indian Space Research Organization (ISRO) launched the first developmental flight of its new Small Satellite Launch Vehicle from its spaceport in Sriharikota.

"All stages performed normal. Both satellites were injected. But the orbit achieved was less than expected which makes it unstable," ISRO informed.

In the latest update to the launch, ISRO informed that the satellites placed were no longer usable due to a deviation caused by salvage action due to logic failure to identify a sensor failure.  

"Satellites placed are no longer usable. Issue is reasonably identified. Failure of a logic to identify a sensor failure and go for a salvage action caused the deviation. A committee would analyse and recommend," ISRO informed, ANI reported.

ISRO developed the SSLV to enable a rapid launch cadence - once a week if necessary - and to launch small and micro satellites with a total payload capacity of 500 kg to low-Earth orbit (LEO). Earlier on August 7, it was reported that the development flight, on the other hand, may not have been a success.

The rocket was reported to have stopped transmitting data nine minutes into the launch and to have missed its intended orbit. The issue appeared to be with the SSLV's terminal stage, known as the velocity trimming module (VTM). The VTM was supposed to burn for 20 seconds at 653 seconds after launch, according to the launch profile. However, it only burned for 0.1 seconds, depriving the rocket of the necessary altitude boost.

After the VTM burn, the two satellites onboard the rocket, the primary EOS-2 Earth-observing satellite and the secondary AzaadiSAT student satellite, separated from the vehicle. 

ISRO hasn't yet labelled the mission a 'failure,' but an unstable orbit indicates that the mission isn't a success, in colloquial terms. ISRO plans to launch the SSLV from its upcoming spaceport in Kulasekarapattinam, Tamil Nadu, in the future. This would allow the rocket to enter a pole-to-pole, or polar, orbit over Earth in a straight geodesic orbit. However, because it was launched from Sriharikota, it entered a relatively diagonal orbit.

Because it is large enough to carry the extra fuel, the larger PSLV rocket launches from Sriharikota and circles Sri Lanka before entering polar orbit. The SSLV has three stages plus the VTM module and is much smaller. It weighs slightly more than 120 tonnes and stands 34 metres tall. According to ISRO, India's private sector should take advantage of the rocket's modularity to manufacture and launch satellites for their needs.

(Image: ANI)