The Fiery Re-entry
The return begins not with a fall, but with a precisely calculated braking manoeuvre. The Gaganyaan service module will fire its engines to slow the spacecraft, allowing Earth's gravity to pull it from orbit. Once the trajectory is set, the service module separates
and burns up, leaving the Crew Module to face the atmosphere alone. Plunging into the air at speeds over 28,000 km/h, the module converts its immense kinetic energy into heat. This creates a superheated plasma bubble around it, with temperatures soaring to 1,800°C. To survive this, the module relies on its Thermal Protection System (TPS), a special ablative heat shield that is designed to burn away in a controlled manner, carrying the intense heat away from the capsule and its precious occupants.
A Ten-Parachute Ballet
Atmospheric drag does most of the initial braking, but it's not enough for a safe landing. This is where a meticulously choreographed parachute sequence takes over. The Gaganyaan module uses a total of ten parachutes of different types to manage its descent. The sequence begins with two Apex Cover Separation parachutes that jettison the protective cover. Then, two drogue parachutes deploy to stabilize the capsule and slow it from supersonic speeds. Following this, three pilot chutes are released, whose job is to pull out the three massive main parachutes. These main parachutes are the final brakes, designed to slow the module to a gentle speed for its splashdown.
Redundancy is Everything
In human spaceflight, you can't leave anything to chance. Every system has a backup, and the parachute system is a prime example. The entire deceleration system is built with redundancy. While there are three main parachutes, the module is designed to land safely with just two. The third one acts as a backup in case one fails to deploy correctly. ISRO, in collaboration with DRDO, has conducted numerous Integrated Airdrop Tests (IMAT), dropping test articles equivalent to the module's mass from aircraft to validate this complex sequence under various conditions, including simulated failures. This rigorous testing ensures the system is robust and reliable for the crewed mission.
Splashdown and Swift Recovery
The final destination is not land, but the waters of the Bay of Bengal. A sea landing is preferred because water is more forgiving and can absorb the impact of a landing at a higher velocity than solid ground. Once the module splashes down, the final phase of the mission begins: recovery. This is a coordinated effort led by the Indian Navy. Using specialised ships equipped with well decks—a part of the ship that can be flooded to allow the capsule to be floated inside—teams will locate, secure, and retrieve the crew module with the astronauts. Extensive trials have been conducted using mock-up modules to perfect these procedures, ensuring the crew can be recovered quickly and safely.
