How will Gaganyaan’s crew module deploy its parachutes?, Pg8

Key Highlights:

• The Gaganyaan crew module will utilize a multi-stage parachute system for a safe soft-landing after re-entry.
• The system comprises pilot, drogue, and main parachutes, deployed sequentially to manage deceleration and opening shock.
• The Defence Research & Development Organisation (DRDO) laboratory, ADRDE in Agra, is developing the parachute system for Gaganyaan.
• The crew module's recovery system incorporates redundancy with two drogue chutes and three main chutes to ensure safety even if one main parachute fails.
• Parachutes are deployed below the speed of sound and detached after splashdown using pyro cutters or mechanical quick-release devices.

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Detailed Insights:

• Spacecraft re-entering Earth's atmosphere primarily use atmospheric drag to reduce velocity, with parachutes providing the final deceleration for a gentle touchdown.
• Multi-staging of parachutes is crucial to prevent high opening shock and dangerous deceleration for the crew, by gradually increasing the parachute diameter.
• The parachute system is designed to eject through the turbulent wake created by the crew module's blunt shape, ensuring rapid and effective deployment.
• Testing platforms like the rail track rocket sled (RTRS) at Terminal Ballistic Research Lab, Chandigarh, are used to validate parachute performance at appropriate velocities.
• Advanced synthetic polymers such as Kevlar for high-load lines, Nomex for heat resistance, and Nylon for canopy broadcloths are used in aerospace parachutes.
• The elasticity of Nylon helps absorb initial dynamic shock loads during inflation and allows for compact packing.
• After landing, immediate detachment of parachutes is essential to prevent the module from being dragged on land or capsizing in water, which could injure astronauts.

Scientific/Technical Concepts Involved:

• Atmospheric Drag: The resistive force exerted by the atmosphere on an object moving through it, used for initial deceleration of spacecraft.
• Multi-staging: The sequential deployment of parachutes of increasing size to control deceleration and reduce opening shock.
• Pilot Chute: A small parachute deployed first to pull out larger drogue or main parachutes.
• Drogue Chute: A medium-sized parachute deployed early in descent to stabilize the module and reduce initial velocity.
• Main Chute: The largest parachute deployed in the final phase to achieve the required low velocity for a soft-landing.