Chennai, Feb 2 (FN Bureau) A Vibration disturbance for a short durationduring the separation of the Second Stage led to the failure of themaiden developmental flight of the Small Satellite Launch Vehicle(SSLV-D1) in August last year, the Indian Space Research Organisation (ISRO) said on Thursday. This was revealed in Failure Analysis report of SSLV-D1 Missionsubmitted to the ISRO. ISRO said the Failure Analysis Committee, which went into thefailure of the first SSLV mission, said detailed analysis of theflight events and observations ranging from countdown, lift-off,propulsion performance, stage separations and satellite injectionrevealed that there was a vibration disturbance for a short durationon the Equipment Bay (EB) deck during the Second Stage (SS2)separation, that affected the Inertial Navigation System (INS),resulting in declaring the sensors faulty by the logic in FaultDetection & Isolation (FDI) software.
It said SSLV is designed to be affordable and amenable to industryproduction and will function as a launch-on-demand platform forMini, Micro or Nano satellites. It is a three-stage vehicle with all solid propulsion stages and liquidpropulsion-based Velocity Trimming Module (VTM) as the terminalstage. The launcher also targets many novel features including low turnaround time, flexibility in accommodating multiple satellites,launch-on-demand, minimal launch infrastructure requirements,etc. The first developmental flight of SSLV lifted off from Satish DhawanSpace Centre (SDSC) on August 7, 2022 at 0918 hrs. The objective ofthe mission (SSLV-D1/EOS-02) was to inject EOS-02 satellite of ISROinto a circular orbit of 356.2 km with an inclination of 37.21 deg. Azaadisat, a student satellite was also accommodated in the mission,authorized by IN-SPACe.
However, the spacecraft were injected into a highly elliptical unstableorbit due to a shortfall in velocity, leading to their decay and deorbitingimmediately, in spite of normal performance of all solid propulsionstages. The orbit achieved was 360.56 km x 75.66 km with an inclinationof 36.56 deg.Initial investigations with the flight data indicated that the lift-off of SSLV-D1was normal along with normal performance of all solid propulsion stages. However, the mission could not be achieved due to an anomaly duringthe SS2 separation, which triggered a mission salvage mode (which isa procedure adopted to attempt minimum stabilized orbital conditionsfor the Spacecraft in case of an anomaly in the vehicle system).