In News:

• India’s human spaceflight programme, Gaganyaan, places paramount emphasis on astronaut safety. To achieve this, ISRO has developed a dedicated Crew Escape System (CES) — a rapid emergency mechanism designed to protect astronauts during the most critical phase of a mission: launch and atmospheric ascent.
• Recently, ISRO also developed a cost-effective single-stage test vehicle powered by the Vikas engine specifically to validate this escape system during flight trials.

Purpose and Importance

• In human space missions, crew safety takes priority over mission success. During launch and the initial ascent through the dense atmosphere, the launch vehicle experiences extreme stresses and accelerates to hypersonic speeds. Any malfunction at this stage — especially with rockets using solid boosters that cannot be shut down once ignited — demands immediate crew evacuation.
• The CES is engineered to rapidly detach the crew module from the launch vehicle in the event of an anomaly and move it to a safe distance within seconds.

How the Crew Escape System Works

The Crew Escape System is mounted on the forward end of the rocket and consists of multiple high-burn-rate solid motors that generate more thrust than the launch vehicle, ensuring faster acceleration of the escape module. Once activated, the CES pulls the crew module away, safely distancing it from the failing rocket.

After separation:

• The escape system detaches from the crew module
• A multistage parachute system deploys
• The module gradually decelerates
• Astronauts splash down safely in the sea

Throughout this sequence, the crew remains inside the pressurised module until recovery.

Decision-Making & Safety Systems

• Activation of the CES is controlled by the Integrated Vehicle Health Management (IVHM) system. This network of sensors, software and diagnostics continuously monitors launch vehicle performance and crew module health in real time.
• It detects anomalies, filters out false alarms, and triggers the escape sequence instantly if required.

Types of Crew Escape Systems

Crew escape mechanisms follow two broad designs:

• Puller type — used in Gaganyaan, where the system pulls the crew module away using high-thrust solid motors. Similar systems were used in the U.S. Saturn V, Russia’s Soyuz, and China’s Long March missions.
• Pusher type — used in systems like SpaceX Falcon-9, where small liquid-fuel engines push the spacecraft away.

ISRO adopted the puller-type design due to its proven reliability in high-stress atmospheric escape scenarios.