ISRO’s Crew Escape System

4. ISRO’s Crew Escape System: NASA astronauts Sunita Williams and Barry Wilmore returned safely after a nine-month ISS mission, highlighting the importance of safety protocols in human spaceflight.

• ISRO, preparing for its maiden human spaceflight mission Gaganyaan, is developing similar safety mechanisms based on past incidents and recent research.
• About ISRO’s Crew Escape System:

o Crew Escape System: It is a tower-like structure atop the human-rated LVM3 rocket to pull the crew module away in case of a malfunction.

o Emergency exit device is activated after ignition to protect crew, unlike satellite-launching LVM3 which lacks such a system.

o Tractor-type system in ISRO’s Crew Escape design uses solid fuel engines to quickly lift the crew module.

o Crew module is attached to the escape tower and disengages from the rocket during emergencies.

o Pad abort scenarios activate both HEM and LEM motors to ensure rapid escape and splashdown in sea.

o Crew Escape System becomes dead weight in normal flights; hence, the LEM is jettisoned at a set altitude to reduce mass.

o Soyuz T-10 (1983) & Blue Origin NS-23 (2022), demonstrated successful use of escape systems.

• About Low-altitude Escape Motor (LEM) & High-altitude Escape Motor (HEM):

o LEM generates enough thrust at initial launch phase to separate crew module from launch vehicle.

o HEM activates at higher altitudes to quickly pull the crew module away to safety.

o Both LEM and HEM are triggered during pad aborts, ensuring rapid ascent and safe distance from the vehicle.