The story to this point: The Gaganyaan mission goals to soundly transport Indian astronauts to a low-earth orbit of round 400 km altitude utilizing the human-rated LVM3 (HLVM3) rocket because the launch car, and to return them safely. In human house missions, crew security is extra essential than mission success. It is crucial that security is addressed throughout all phases: launch pad, ascent, orbit, and descent.
What is the CES?
A devoted Crew Escape System (CES) will likely be used in the course of the preliminary a part of the atmospheric section of the Gaganyaan mission to make sure crew security within the occasion of a contingency that jeopardises the mission. The CES is designed to quickly separate the crew module, together with the crew, from a malfunctioning launch car, and transfer it to a secure distance within the least potential time. The atmospheric section of flight is without doubt one of the most important levels of the ascent, throughout which the rocket accelerates to hypersonic speeds — greater than 5 instances the velocity of sound — and will likely be experiencing very excessive structural hundreds. The HLVM3 rocket is supplied with two highly effective S200 solid-fuel boosters to raise off, and in contrast to liquid or cryogenic engines, stable motors can’t be shut down as soon as they’re ignited. Thus, the CES should extract the crew module with better acceleration than the launch car itself, and in minimal time. The CES is a quick-acting system positioned on the ahead finish of the launch car and is supplied with a number of special-purpose stable motors. These motors use excessive burn-rate propellants that eat gasoline quicker than standard stable motors, producing increased acceleration.
In the Gaganyaan mission, the CES might impart acceleration as much as 10-times that of gravity. For a wholesome human physique, such excessive acceleration is tolerable for a number of seconds if the crew is positioned accurately, with the acceleration appearing perpendicular to the chest and the physique pressed in opposition to the seat in a “child in cradle” orientation. Rocket techniques are extra intricate than these of plane, with rocket reliability a lot decrease than that of passenger plane. Nevertheless, the CES considerably improves crew survival chance by means of its heritage-based design, redundant techniques, and strong mission planning.
What are differing types?
The CES is classed into two varieties based mostly on the way in which it extracts the crew module: (i) puller sort — utilized in Gaganyaan, the place the CES pulls the crew module away from the launch car; (ii) pusher sort — utilized in autos like SpaceX’s Falcon 9, the place the crew module is pushed away utilizing compact, high-thrust liquid-fuel engines. Both techniques have benefits and downsides, with the selection relying on propulsion know-how and system integration features. The U.S.’s Saturn V, Russia’s Soyuz, and China’s Long March autos additionally use puller-type CES designs.
In September, 1983, two Soviet cosmonauts escaped an enormous explosion on the launchpad when their Soyuz rocket caught fireplace simply earlier than lift-off. Their lives had been saved by the launch car’s automated crew escape system. This stays the primary and solely time a crewed launch escape system was activated earlier than lift-off.
Once the CES has moved the crew module a secure distance away from the failing car, the module will likely be launched and decelerated by a multistage parachute system. This will scale back the module’s velocity in steps, guaranteeing it splashes down safely within the sea with out exceeding the crew’s physiological limits upon affect. Typically, the crew will stay contained in the module till splashdown. But in the course of the Soviet Union’s first human spaceflight, Yuri Gagarin ejected from the Vostok module at roughly 7 km altitude and parachuted safely to the bottom.
The Integrated Vehicle Health Management system (IVHM), which is a community of sensors, electronics, and software program, will help in taking a call to activate the CES when a contingency arises. It will monitor all vital parameters of car techniques and crew well being in actual time. Based on the synthesised info and the flight regime, it can guarantee immediate anomaly detection, minimise false alarms, and activate the CES early sufficient to guard the crew.
Has it been examined?
The ISRO has developed a cheap, single-stage Test car powered by the Vikas engine to validate the CES. The first profitable check occurred in October 2023, throughout which the CES was activated when the Test car reached transonic situations — a important section in atmospheric flight when the speed transitions from subsonic to supersonic. ISRO plans further Test car flights to simulate different important ascent trajectory situations. The CES is a cornerstone of the Gaganyaan programme and displays ISRO’s dedication to astronaut security. By integrating superior engineering, rigorous testing, and dependable techniques just like the IVHM, the CES ensures India’s first human spaceflight mission will prioritise the secure return of its crew, even within the face of unexpected challenges.
Unnikrishnan Nair S. is former director, VSSC; Founding Director, HSFC; and an skilled in orbital reentry and human spaceflight applied sciences.
