The current protected return of NASA astronauts Sunita Williams and Barry Wilmore after a nine-month keep onboard the International Space Station (ISS) underscored the significance of following safety protocols. While these protocols have been hidden from view, they allowed NASA to ensure that the astronauts weren’t harmed bodily or mentally in the middle of their unpredictable Starliner take a look at mission. The Indian Space Research Organisation (ISRO) is at present placing comparable protocols in place because it prepares for its maiden human spaceflight mission, Gaganyaan. In this endeavour, its scientists and engineers are drawing from each the most recent in analysis and incidents and accidents of the previous.
Human spaceflight has three key phases: launch, orbit, and reentry. Let’s discover safety protocols in every section.
Before and through launch
On the launchpad: In 1967, three members of NASA’s Apollo-1 crew met with tragedy when the crew capsule they have been testing on a launchpad in Florida — even earlier than the rocket took off — caught fireplace, killing all of them. Should an identical incident recur at this time, the crew might want to flee the realm shortly. Thus, ISRO has put in ziplines and a fireproof bubble raise at its second launch pad at SHAR in Sriharikota.
After ignition till orbital insertion: A human-rated launch car contains an emergency exit gadget, just like the again door of a bus, to be activated in case a life-threatening incident happens after the rocket has lifted off. In distinction to the Launch Vehicle Mark-3 (LVM3), ISRO’s medium-lift launch car that lifts satellites, the human-rated model will characteristic a tower-like construction on prime.
The crew module is fixed to this tower-like construction. In case of a launch car malfunction, the crew module and its escape mechanism will first disengage from the principle rocket, then, the escape tower’s stable gas engines — designed to ignite shortly — will produce an incredible quantity of thrust in a brief time frame, propelling the area capsule upwards and away from the rocket.
This is the Crew Escape System. On the human-rated LVM3, it is tractor-type, that means a strong engine will pull the crew module away from hurt. The SpaceX Crew Dragon capsule utilises a pusher-type system the place the system is situated beneath the crew module and pushes it away from the principle rocket.
During launch: The crew escape mechanism operates in three modes relying on the altitude obtained throughout the emergency. ISRO’s Crew Escape System has two forms of motors: the Low-altitude Escape Motor (LEM), which might generate sufficient thrust to propel the crew module away from the launch car throughout the preliminary section of the flight, and the High-altitude Escape Motor (HEM), which can kick in at excessive altitude to supply sufficient pull to yank the crew module shortly to a protected distance from the rocket.
Pad abort: This is when the emergency escape has to happen moments after ignition. Both the HEM and LEM motors of the Crew Escape System are activated to quickly transport the entire crew escape meeting and capsule to a protected distance within the shortest period of time. In low-altitude abort eventualities, each motors are triggered; nonetheless, now, the crew module will splash down at a chosen spot within the sea. In regular circumstances, the Crew Escape System is successfully lifeless weight. Therefore the LEM — which is the pencil-like factor of the tower — is jettisoned at a particular top to cut back weight whereas the HEM stays hooked up to the crew module.
The Soyuz T-10 rocket caught fireplace on the launchpad simply earlier than liftoff in 1983. The crew might evacuate safely due to the Crew Escape System. Similarly, one minute into the Blue Origin New Shepard flight NS-23 on September 12, 2022, a launch engine failed and the launch escape gadget labored as meant, permitting the capsule to detach and land safely.
Entering and staying in orbit
ISRO’s Gaganyaan crew capsule, which can transport people, consists of a pair of interconnected modules. The crew module serves because the dwelling quarters for the crew and passengers if any whereas the service module carries the gas, engines, management techniques, and so forth.
By the time the capsule will get near its meant orbit, all elements of the crew escape techniques can have been launched into area. In this case, the capsule’s onboard propulsion system, within the service module, will launch the crew module onto a sub-orbital trajectory if emergency evacuation is required.
In the occasion of an emergency after the spacecraft is in orbit, the service module’s propulsion system and the crew module’s thrusters will collectively try and reenter the earth’s environment, in direction of the bottom.
At the ISS
Gaganyaan isn’t anticipated to dock with any area station, however its crew will nonetheless be familiarised with the established procedures for docking.
After docking, step one is to maintain the capsule docked as a ‘lifeboat’ within the occasion of an emergency aboard the station. When the capsule that carried Williams and Wilmore to the ISS malfunctioned, NASA launched one other with two vacant seats and docked it to the ISS throughout their mission. There have been two capsules at any time — one SpaceX Crew Dragon and one Russian Soyuz — with passenger capability to fly them again.
The area station is additionally to have a ‘safe refuge’ area the place its occupants might go to flee any hazard, comparable to a hearth, collision with area particles, or greater doses of radiation launched in a photo voltaic flare. This space could be airlocked and saved aside from the remainder of the module.
Returning to the earth
The most difficult a part of spaceflight is reentry. Orbiting the earth is like using a bicycle: in an effort to preserve from falling down, you must preserve transferring ahead. Any capsule not firing its thrusters in orbit will slowly be pulled again by gravity and atmospheric drag. When reentry is fascinating, the capsule will fireplace its thrusters accordingly to start its descent, controlling its pace whereas additionally making an attempt to make sure it lands in a selected area on the bottom.
Once reentry has begun, atmospheric friction will warmth the capsule’s outer warmth protect to as much as 1,800º C. The crew within the crew module can be protected by the protect. Once the capsule has descended to a selected altitude, the crew will gradual its descent utilizing retrograde thrusters and deploy parachutes.
The Gaganyaan crew capsule will decelerate all through reentry utilizing a 10-parachute system. Its apex cowl separation parachutes will deploy when it is 15.3 km from the bottom and travelling at 276 m/s, After that, a pilot chute will deploy drogue parachutes, stabilising and decelerating the capsule to 70 m/s as much as a top of three km. Then pilot parachutes will deploy and open the three major canopies, lowering the drop pace to 10-12 m/s. The parachute can be disconnected as soon as the capsule has splashed down utilizing a pyrotechnic launch mechanism.
T.V. Venkateswaran is a science communicator and visiting school member on the Indian Institute of Science Education and Research, Mohali.
Published – April 15, 2025 08:30 am IST
