How the Gaganyaan crew module is built to survive, Pg10

Key Highlights:

• Gaganyaan is India's maiden crewed space mission, designed to transport Indian astronauts to space and ensure their safe return to Earth.
• The mission will use the Human-rated Launch Vehicle Mark (HLVM) 3 to inject the Orbital Module (OM) into the desired orbit.
• The Orbital Module (OM) comprises a Crew Module for astronauts and a Service Module for on-orbit support.
• The Crew Module is designed with a sphere-cone configuration to withstand intense thermo-structural loads during re-entry and ensure a safe splashdown.

Gaganyaan.png

Detailed Insights:

• The Service Module provides propulsion and separates from the Crew Module before re-entry, burning up in the atmosphere.
• The Crew Module decelerates through aero-braking during descent, designed to manage aerodynamic lift and drag for a controlled re-entry.
• A sphere-cone configuration is preferred for re-entry bodies as its blunt base generates a detached shockwave, pushing heat away, while the conical body provides stability.
• The Gaganyaan Crew Module has two distinct stable aerodynamic and hydrodynamic positions, managed by control thrusters and an up-righting system post-splashdown.
• Dynamic instability, characterized by uncontrolled oscillations during atmospheric deceleration, is a critical challenge addressed by the module's design and control mechanisms.
• Other crewed spacecraft, like Russia's Soyuz and China's Shenzhou, often use a three-module configuration, with an additional module for extra living space and docking.

Scientific/Technical Concepts Involved:

• Orbital Module (OM): The combined spacecraft unit housing the crew and providing necessary support for the mission in orbit.
• Crew Module: The habitable section of the spacecraft designed to carry astronauts and safely return them to Earth.
• Service Module: The uncrewed section of the spacecraft providing propulsion, power, and life support systems for the Orbital Module.
• Aero-braking: A technique using atmospheric drag to slow down a spacecraft, reducing the need for propulsive braking.
• Mono-stability: The characteristic of a re-entering body to maintain a single, stable orientation during atmospheric flight or after splashdown.
• Dynamic Instability: A condition where a re-entry module experiences rapidly growing and uncontrolled oscillations during atmospheric deceleration.