ISRO SSLV-D1/EOS-02 mission suffers data loss in its terminal phase

The Indian Space Research Organisation (Isro) on Sunday said its SSLV-D1/EOS-02 mission suffered a data loss in its terminal phase.

"We are processing the data to conclude on the final outcome of the mission with respect to whether a stable orbit is achieved or not," said Isro chairman S Somanath.

ISRO tweeted, "SSLV-D1/EOS-02 Mission: 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."

The Small Satellite Launch Vehicle or SSLV carrying EOS-2 and Azaadisat satellites lifted off from the first launch pad of Satish Dhawan Space Centre in Sriharikota at 9.18am, after the countdown for the mission began at 2:26am.

The 120-tonne SSLV, which is an all-solid stage rocket measuring 34 metre in height and two metre in diameter, is capable of launching mini, micro or nano satellites weighing 10 to 500kg mass to 500km planar orbit. SSLV is a three-stage vehicle. All these three are solid propulsion stages.

The key features of SSLV include low cost, low turnaround time, flexibility in accommodating multiple satellites, launch-on-demand feasibility, minimal launch infrastructure requirements.

The rocket can be made within one week because of many innovative features introduced. These include modular systems, simplified pyro circuit and modular feature for separation system, multi-satellite adapter deck, miniature low-cost avionics with commercial off-the-shelf components, on-board computer with rapidly reconfigurable check-out system with minimum ground interface.

Some of the new systems introduced in the launch vehicle include SS1 motor, which is the third largest solid booster of Isro, SS3 motor, which is a new composite upper stage solid motor, and liquid propulsion-based terminal stage for precise injection of satellites.

Two satellites

The 145kg EOS-2 is an experimental imaging satellite with a short turn-around time.

Azaadisat is an 8U Cubesat weighing around 8kg. It carries 75 different payloads each weighing around 50gram and conducting femto-experiments. The payloads were built by girl students from rural regions across the country. 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.