Gaganyaan Episode 6: Life support: Living in space | The Scope
A recent explainer segment examined the Environmental Control and Life Support System (ECLSS) being built for Gaganyaan, India's first crewed spaceflight programme, focused on how the Crew Module will sustain three astronauts in a sealed cabin.
The system covers oxygen supply, carbon dioxide removal, temperature and humidity control, cabin pressure regulation, drinking water supply, waste management, and fire detection/suppression.
ISRO has developed the ECLSS indigenously after efforts to source elements of the technology from other space agencies did not materialise, and has tested an ECLSS engineering model on the ground.
The system is one of the human-rating milestones being validated ahead of the uncrewed Gaganyaan test flights (G1, G2) that precede the crewed H1 mission.
Environmental Control and Life Support System (ECLSS)
ECLSS is the set of thermal, chemical, and mechanical engineering subsystems that replicate a habitable Earth-like environment inside a sealed spacecraft cabin. Because a crew module has no access to Earth's atmosphere, ECLSS must continuously regenerate breathable air, remove metabolic and chemical waste, and hold pressure, temperature, and humidity within survivable limits for the full mission duration.
Key Details
- Oxygen supply: stored in onboard pressurised tanks and released to the cabin at survivable partial pressure; astronaut-exhaled carbon dioxide is scrubbed using CO2-absorbing chemical canisters (e.g., lithium hydroxide) and related mechanisms such as molecular sieves and catalytic oxidisers for trace-contaminant control.
- Thermal and humidity control: maintains cabin temperature and humidity within a narrow habitable band, since equipment heat and human perspiration would otherwise destabilise the cabin atmosphere.
- Water and waste management: pressurised systems supply potable water; suction-based systems collect and chemically treat human waste in microgravity, where liquids and solids do not settle under gravity.
- Fire safety: specialised smoke detectors and water-mist (not conventional spray) extinguishers are used, because fire behaves differently in microgravity — flames are spherical and smoke does not rise.
- ISRO announced indigenous development of ECLSS for Gaganyaan after international technology-sharing routes for a human-rated life support system did not come through, making it a case study in India's self-reliant ("Atmanirbhar") critical space technology.
The explainer's walkthrough of oxygen/CO2, thermal, water, waste, and fire subsystems maps directly onto the ECLSS engineering model ISRO has built and ground-tested for the Gaganyaan Crew Module, ahead of validating it in orbit via the uncrewed G1/G2 flights before the crewed H1 mission.
Gaganyaan Mission Architecture
Gaganyaan is India's human spaceflight programme, intended to send a three-member crew to low Earth orbit for up to a few days and return them safely, making India the fourth country (after the erstwhile Soviet Union/Russia, the United States, and China) to independently launch humans to space.
Understanding ECLSS requires situating it within the larger Gaganyaan architecture — the HLVM3 vehicle that lifts the Orbital Module, the Crew Module that ECLSS keeps habitable, and the uncrewed test flights that de-risk the life support systems before humans fly.
- Gaganyaan would make India the fourth nation to independently launch a crewed spaceflight, after the Soviet Union/Russia, the United States, and China.
- Launch vehicle: HLVM3 (human-rated LVM3), with S200 solid boosters, L110 liquid stage, and C32 cryogenic upper stage.
- Mission sequence: uncrewed G1 and G2 test flights precede the crewed H1 mission; G1 is set to carry the humanoid robot Vyommitra.
- ECLSS subsystems: oxygen supply and CO2 scrubbing (e.g., lithium hydroxide canisters), thermal/humidity control, pressurised water supply, waste collection/treatment, and fire detection with water-mist suppression.
- ISRO has developed the ECLSS indigenously and ground-tested an ECLSS engineering model as part of Gaganyaan's human-rating process.