Sriharikota (AP), Aug 7: The next generation maiden flight of India's Small Satellite Launch Vehicle (SSLV-D1--developmental flight) on Sunday suffered a set back as the both the satellites--earth observation satellite EOS-02 and AzaadiSat--carried by it were placed in an elliptical orbit instead of circular orbit and the satellites were no longer usable.
Hours after the mission took place from the First Launch Pad at 0918 hrs from the SHAR Range, ISRO Chairman Dr.S.Somanath, in a video address, said the SSLV-D1, after taking off majestically and the normal performance of all the three stages, placed the satellites into 356 km x 76 km elliptical orbit instead of 356 km circular orbit – 76 km is the lowest point close to the surface of the earth.
He said when the satellites are placed in such an orbit, they will not stay there for long and will come down.
“The two satellites have already come down from that orbit and they are no longer usable,” he said.
He said going forward a set of experts will look into the failure and identify why it went into an unacceptable orbit. After carrying out the small corrections and revalidation of the corrections ISRO will go for the next SSLV-D2 launch soon, Somanath added.
Earlier, in an update, ISRO said SSLV-D1 placed the satellites into 356 km x 76 km elliptical orbit instead of 356 km circular orbit.
"Satellites 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", it said.
A committee would analyse and recommend. With the implementation of the recommendations, ISRO will come back soon with SSLV-D2, it said.
Earlier, ISRO said SSLV-D1 successfully injected both the satellites after separation, but the orbit achieved was less than expected, which makes it unstable.
"All the stages performed normal. Both the satellites were injected. But, the orbit achieved was less than expected, which makes it unstable."
The three stage SSLV-D1, the first developmental flight, carrying 135 kg earth observation satellite EOS-02 and 8 kg 8U Cubesat AzaadiSat, took off from the First Launch Pad as scheduled at 0918 hrs after a smooth seven hour countdown.
The performance of all the three stages--ignition and separation and the coasting period during the separation of the second and third stage--were normal.
Somanath said "after both the satellites got separated and were injected into the orbit, an anomaly was noticed and we lost data connectivity with the launch vehicle and the satellites."
"Failure of a logic to identify a sensor failure and go for a salvage action caused the deviation", he said, adding the ISRO would come back with SSLV-D2 mission after revalidating the anomaly and carrying out nessary corrective measures, the ISRO Chief, who is also the Secretary, Department of Space, said.
Except this anomaly, all the technologies used in the SSLV-D1, including propulsion systems, performed really well, he added.
The injection of the satellites was clearly visible in the giant screens at the media centre.
Earlier, soon after the launch, Somanath in a brief address from the Mission Control Centre, said "Maiden flight of SSLV is completed. All stages performed as expected. Data loss is observed during the terminal stage. It is being analysed. Will be updated soon."
Later, in an update ISRO said SSLV successfully injected both the satellites after separation, but the orbit achieved was less than expected, which makes it unstable, which was followed by another update--which stated that the satellites were injected into an elliptical orbit instead of the circular orbit and were no longer usable--and Somnath's video address.
SSLV-D1 is a 34 m tall, 2 m diameter vehicle having a lift-off mass of 120 T. EOS-02 is an earth observation satellite designed and realised by ISRO. This microsat series satellite offers advanced optical remote sensing operating in infra-red band with high spatial resolution. The bus configuration is derived from IMS-1 bus.
AzaadiSAT is a Cubesat and carried 75 different payloads each weighing around 50 grams and conducting femto experiments.
Girl students from rural regions across the country were provided guidance to build these payloads. The payloads are integrated by the student team of “Space Kidz India”.
The payloads include a UHF-VHF Transponder working in ham radio frequency to enable voice and data transmission for amateur radio operators, a solid state PIN diode-based Radiation counter to measure the ionising radiation in its orbit, a long-range transponder and a selfie camera. (UNI)