The South India times Chennai: ISRO successfully con- ducts Gaganyaan’s LEM static test of Crew Escape System The Indian Space Agency achieved yet another milestone when it successfully conducted the Low Altitude Escape Motor (LEM)Static Test of Crew Escape System for its first manned Gaganyaan mission.
ISRO sources today said another important milestone in the Gaganyaanproject is completed, by successfully test-firing the LEM of Crew EscapeSystem (CES), from Sriharikota yesterday. The CES takes away the Crew module of the Gaganyaan mission in case of any eventuality and rescues the astronauts.
In case of mission-abort during the initial phase of flight, LEM provides the required thrust to CES, to take away Crew Module from the launch vehicle. LEM is a distinctive special-purpose solid rocket motor with four reverse flow nozzles and generates a maximum sea level thrust of 842 kN (nominal)with a burn time of 5.98 s (nominal).
“The nozzle end of LEM is mounted at the fore end of the launch vehicle unlike at aft end in conventional rocket motors to avoid exhaust plume impingement on crew module. This necessitates the use of reverse flow multiple nozzles in this solid rocket motor. The reverse flow nozzle implies the reversal of the exhaust gas flow direction in the nozzle region”, ISRO said.
The main objectives of the static test were to evaluate motor ballistic- parameters, validate motor subsystem performance and confirm the design margins, evaluate the thermal performance of nozzle liners- especially to confirm the erosion/ablative characteristics, validate the integrity of all interfaces, besides evaluation of the head- end mounted safe arm.
