How the Gaganyaan crew module is built to survive
Ahead of the uncrewed Gaganyaan-1 (G1) test flight, explainers on the mission have detailed how the Crew Module and Service Module are engineered to survive the descent from orbit back to Earth.
After orbital operations are complete, the Service Module fires its engines to de-orbit the spacecraft; the Crew Module then separates and re-enters the atmosphere alone, protected by an ablative heat shield designed to withstand extreme re-entry heating.
ISRO recently conducted qualification tests of the Crew Module's Main Parachute system, and separately cleared a set of Crew Module system tests, as part of continuing preparations for the G1 uncrewed flight.
The Crew Module is designed to splash down in the Bay of Bengal under a multi-stage parachute system, for recovery by the Indian Navy.
Indian Human Spaceflight Programme (Gaganyaan) — Structure and Timeline
Gaganyaan is India's human spaceflight programme under ISRO, intended to demonstrate indigenous capability to send a crew to low Earth orbit and return them safely. The programme proceeds through uncrewed test flights before any crewed mission is attempted, and builds on decades of earlier re-entry and life-support technology demonstrations.
Key Details
- ISRO's first re-entry technology demonstration relevant to Gaganyaan was the Crew Module Atmospheric Re-entry Experiment (CARE), launched on the LVM3-X sub-orbital test on 18 December 2014, which validated crew-module aerodynamics, thermal protection, and parachute deployment down to splashdown in the Bay of Bengal.
- The final Gaganyaan crew module design was completed in 2019.
- The current test sequence involves uncrewed missions G1, G2, and G3, followed by the first crewed mission (H1); G1 has been targeted for 2026, with the crewed flight expected thereafter.
- The programme uses the human-rated LVM3 launch vehicle (also called HLVM3 in its human-rated configuration), ISRO's most powerful operational rocket.
The Crew Module's re-entry survival systems being tested now are a direct evolution of the technology first proven in the 2014 CARE experiment, refined over a decade of design and qualification work ahead of the G1 flight.
Crew Module and Service Module — Orbital Module Architecture
The Gaganyaan spacecraft in orbit consists of two connected parts: the Crew Module (CM), a pressurised, human-rated capsule that houses the astronauts and their life-support systems, and the Service Module (SM), an unpressurised module providing propulsion, power, and thermal management while in orbit. Together they form the "Orbital Module"; only the Crew Module returns to Earth.
Key Details
- The Crew Module has a mass of roughly 5 to 5.3 tonnes; combined with the roughly 2.9-tonne Service Module, the Orbital Module totals approximately 8.2 tonnes.
- The Service Module Propulsion System uses a bipropellant combination (MON-3 oxidiser and monomethylhydrazine fuel) with five main liquid-apogee-motor-derived engines (each around 440 N thrust) and sixteen smaller reaction control system thrusters for attitude control.
- Before re-entry, the Service Module separates from the Crew Module after performing the de-orbit burn; it is not designed to survive re-entry and burns up or falls away separately.
- The Crew Module is designed to support up to a three-member crew for a mission duration of about seven days in low Earth orbit.
Understanding this division is central to the explainer's focus — only the Crew Module needs re-entry protection, since the Service Module's role ends once it completes the de-orbit manoeuvre.
Thermal Protection System (Ablative Heat Shield)
Re-entry into the atmosphere at orbital speeds generates intense aerodynamic heating, requiring the Crew Module to be protected by an ablative Thermal Protection System (TPS) — a shield that absorbs heat by controlled, gradual burning away (ablation) of its outer material, rather than by insulating alone.
Key Details
- Re-entry temperatures on the Crew Module's heat shield have been reported to exceed 1,600°C.
- ISRO evaluated Carbon Phenolic composite, Silica Phenolic composite, and Medium Density Silica Phenolic as candidate TPS materials for different zones of the module.
- In the 2014 CARE test, the forward (highest-heating) heat shield used carbon phenolic tiles, while the side panels used medium-density ablative (MDA) tiles — a tiered approach based on expected heat flux across the capsule's surface.
- This is conceptually similar to ablative heat shields used on other crewed capsules internationally (e.g., NASA's Apollo and Orion capsules), reflecting a globally standard approach to capsule re-entry protection distinct from the reusable tile system used on the Space Shuttle.
The ablative heat shield is the core engineering answer to "how the crew module survives" — it is what the explainer is centred on, converting lethal re-entry heat into controlled material loss rather than structural failure.
Parachute Deceleration and Recovery System
After atmospheric re-entry sheds most of the module's orbital velocity, a sequenced, multi-stage parachute system further decelerates the Crew Module for a safe splashdown, since the module's blunt aerodynamic shape alone cannot slow it to a survivable landing speed.
Key Details
- The main parachutes are conical ribbon-type canopies roughly 5.8 metres in diameter, using a single-stage reefing mechanism (a temporary restraint that limits initial canopy opening) to reduce opening shock.
- In July 2026, ISRO conducted qualification tests of the Main Parachute system for the G1 flight, simulating various real-world deployment conditions.
- The Crew Module is designed to splash down in the Bay of Bengal, with recovery to be carried out by the Indian Navy — mirroring the recovery approach used in the 2014 CARE test.
- Parachute deployment in the CARE test occurred at approximately 15 km altitude, after the module's own reaction control thrusters had reduced speed at higher altitudes (thrusters cut off around 80 km, following separation from the launch vehicle at 126 km).
The recent parachute qualification tests referenced in current reporting are the latest milestone in validating the descent-and-recovery chain the explainer describes.
- CARE (Crew Module Atmospheric Re-entry Experiment) test flight: 18 December 2014, on LVM3-X.
- Crew Module design finalised: 2019; Crew Module mass: approximately 5–5.3 tonnes; combined Orbital Module (CM+SM) mass: approximately 8.2 tonnes.
- Reported peak re-entry heat shield temperature: over 1,600°C.
- Main parachute canopy diameter: approximately 5.8 metres (conical ribbon-type, single-stage reefing).
- Test sequence: uncrewed G1, G2, G3 missions precede the first crewed mission, H1; G1 targeted for 2026.
- Launch vehicle: human-rated LVM3 (HLVM3).