SPACE LAUNCH REPORT SSLV Flight History by Variant/Year (2022-Present) by Ed Kyle, Last Update 12/31/2023 L(F) = Number of Launches(Number of Failures) SSLV Year L(F) L(F) L(F) L(F) L(F) ------------------------------------------------------------------ 2020 - - - - 2021 - - - - 2022 1(1) - - - 2023 1(0) - - - ------------------------------------------------------------------ SSLV L(F) L(F) L(F) L(F) L(F) ------------------------------------------------------------------ Suborb - - - - - Orbit 2(1) - - - - Total 2(1) - - - - ------------------------------------------------------------------ SSLV Vehicle Configurations ================================================================== Payload Config. Height Mass (tonnes) (meters) (tonnes) (1) 500 km x 37 deg (2) 500 km x 98 deg ================================================================== SSLV 0.5 t (1) 3-stg solid 34 m 120 t + liquid VTM ================================================================== SSLV Vehicle Components Stg 1 Stg 2 Stg 3 Stg 4 PLF ================================================================== Diameter (m) 2 2 1.7 2 2.1 Length (m) 22.5 3.2 2.8 Mp (tonnes) 87 7.7 4.5 0.05 GLOW (tonnes) Propellant Solid Solid Solid Lquid T (SL tonnes) 244.5 T (VAC tonnes) 23.9 16.32 0.041 ISP (Vac sec) Burn Time (sec) 117 121 112 20+ Engines/Motors 1 1 1 8 thrust + 8 RCS Engine S85 S7 S4 VTM Mfgr ISRO ISRO ISRO ISRO ================================================================== SSLV LAUNCH HISTORY DATE VEHICLE ID PAYLOAD MASS(t) SITE* ORBIT* ------------------------------------------------------------------ 08/07/22 SSLV D1 EOS-2/AzaadiSAT 0.153 SR 1 [FTO] 02/10/23 SSLV D2 EOS-7/Janus-1/AsaadiSAT-2 0.177 SR 1 LEO ------------------------------------------------------------------ NOTES by Vehicle ID [D1] 03:48 UTC. Inaugural launch of India's Small Satellite Launch Vehicle (SSLV). Velocity Trim Module (VTM, 4th stage) shut down 0.1 sec into planned 20 second insertion burn. Made 76 x 356 km versus planned 356 km x 37.2 deg circular orbit. Reentered over Pacific Ocean. Sensor and software failure. Stage 2 separation shock transient not filtered in software, caused INS to go into "salvage mode". [D2] 0348 UTC. First SSLV success. 450 km x 37.2 deg orbit. SPACE LAUNCH REPORT Small Satellite Launch Vehicle (SSLV) India's New Smallsat Launcher by: Ed Kyle Small Satellite Launch Vehicle (SSLV) is a simplified launcher meant to boost 500 kg or more into Low Earth Orbit. It is 34 x 2 meters and weighs 120 tonnes at liftoff. SSLV uses three solid stages topped by a liquid Velocity Trim Module (VTM). The second stage is the same as the PSLV PS3 motor, with 7.7 tonnes of propellant. Stages 1 and 3 are brand new. The SS1 first stage uses three segments and is loaded with 87 tonnes of propellant. The SS3 third stage is a composite case filled with 4.5 tonnes of proplellant. The VTM has sixteen 50-Newton thrusters, 8 for RCS and 8 for a xial thrust, that burn MMH/MON3. It provides the final impulse after the solids burn out. Development was slowed by the failure of the initial first stage static test burn during March 2021. A resonance caused the nozzle to eject about 60 seconds into the burn. After redesign, a second static test succeeded on March 14, 2022. On August 7, 2022, the inaugural launch (D1) failed when the VTM fourth stage shut down 0.1 sec into its planned 20 second insertion burn. The satellites and VTM reached an unstable 76 x 356 km orbit versus the planned 356 km x 37.2 deg circular orbit. The vehicle reentered over the south Pacific Ocean. ISRO announced that the cause was due to a sensor failure, combined with software issues. The shock transient from the Stage 2 separation event, picked up by INS accelerometers, was not properly filtered by guidance software. The sensor data caused the INS to go into "salvage mode", which prevented the vehicle from reaching orbit. The second SSLV launch (D2, for Development-2) successfully reached orbit on February 10, 2023. It carried 156.3 kg EOS-7, 8.7 kg AzaadiSAT-2, and 11.5 kg Janus-1 into a 450 km x 37.2 deg orbit. The flight proved INS software fixes for the issue that caused the SSLV-D1 failure. *ABBREVIATIONS SITE JQ: Jiquin Satellite Launch Center ORBIT LEO: LOW EARTH ORBIT LEO/S: SUN SYNCHRONOUS LOW EARTH ORBIT SUB: SUB-ORBITAL MISSION [FTO]: FAILED TO ORBIT [LEO]: UNPLANNED LEO References