File photo of Gaganyaan project successfully test-firing the Low Altitude Escape Motor of Crew Escape System (CES), from Sriharikota. (Photo: PTI)
NELLORE: Indian Space Research Organisation (Isro) announced on Wednesday night the completion of another important milestone in Gaganyaan project by successfully test-firing the Low Altitude Escape Motor (LEM) of Crew Escape System (CES) from Sriharikota.
In case the Gaganyaan mission has to be aborted during the initial phase of its space flight, CES takes away the Crew Module of Gaganyaan mission, thereby rescuing the astronauts. LEM provides the required thrust to CES to take away the Crew Module from the launch vehicle.
According to Isro, LEM is a distinctive special purpose solid rocket motor with four reverse flow nozzles. It 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 fore end of the launch vehicle, unlike aft end in conventional rocket motors. This is to avoid exhaust plume impingement on the crew module. It necessitates use of reverse flow multiple nozzles in the solid rocket motor. The reverse flow nozzle implies reversal of the exhaust gas flow direction in the nozzle region.
The main objectives of static test include evaluation of motor ballistic parameters; validate motor subsystem performance and confirm design margins; evaluate thermal performance of nozzle liners, especially to confirm erosion / ablative characteristics; and validate the integrity of all interfaces.
In addition, the test evaluated the head-end mounted safe arm (HMSA)-based ignition system performance and side thrust due to misalignment, apart from variation in flow and other functional parameters, including flow reversal.