Bengaluru: India’s maiden human spaceflight mission — Gaganyaan — will take three astronauts to space inside a cramped but heavy capsule, which will orbit the Earth for at least three days before heading back and crashing into the Indian Ocean.
The Indian Space Research Organisation (ISRO) is developing the Rs 9,000 crore mission with a projected launch sometime next year. On 27 February, Prime Minister Narendra Modi announced the names of four astronaut candidates shortlisted for the mission.
The Gaganyaan crew will have life support systems, environmental control systems, emergency escape systems, and more to survive in space. The return will be made possible by specialised parachutes. ThePrint explains the various components of the mission and what stage of development they are in today.
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Gaganyaan structure
The entire spacecraft flying into the Earth’s orbit is called the orbital module. It consists of two parts — the service and crew modules. The crew module, a pyramid-shaped cramped structure, will house the astronauts. The service module enables the spacecraft to enter the orbit and later leave the orbit and descend to surface.
ISRO’s LVM3 rocket will take the Gaganyaan craft into space. The orbital module will separate from the LVM3 before reaching the Earth’s orbit. Then, five engines, parts of the propulsion system in the service module, will fire to put the orbital module into orbit.
During the return journey, the service module engines will fire again to break the modules away from the orbit and make it head towards the Earth.
The service module remains attached to the crew module till the crew module starts entering the Earth’s atmosphere. At that point, the service module breaks away and burns up in the atmosphere, allowing the crew module to descend further.
The crew module is fully autonomous, primarily consisting of the Environmental Control and Life Support System (ECLSS), responsible for producing oxygen, maintaining pressure, adjusting temperature, etc.
ISRO tried procuring this system from other countries but later developed the technology itself.
The crew module also contains the Crew Escape System (CES), which can be activated during launch and remain active within the atmosphere only for use in case of emergencies.
For the descent, the crew module has parachutes, two types for redundancy. These parachutes get deployed during the re-entry of the crew module into the Earth’s atmosphere. They greatly slow down the accelerating crew module before making it splash down gently.
The crew module can carry a maximum of three people.
Launch vehicle
The Launch Vehicle Mark-3 rocket’s human-rated variant (HLVM3) will launch the Gaganyaan mission. The spacecraft will fly on top of the HLVM3 until it reaches orbit.
The HLVM3 is a three-stage launch vehicle and can carry 10,000 kg to low earth orbit and 400 kg to geostationary orbit. It weighs 640,000 kg and stands 44 m tall and 4 m wide. It is a medium-lift vehicle, similar to Atlas V or Falcon 9.
A solid propellant powers the HLVM3 first stage. The first stage takes the spacecraft from Earth to high above the atmosphere before breaking away and burning up.
The second stage has two Vikas engines, which burn liquid propellant through the upper reaches of the atmosphere. Later, the second stage also breaks away.
Then, the third stage powers the spacecraft through its cryogenic engines. The third stage houses the spacecraft and launches it towards the destination orbit before breaking away.
The LVM3 rocket has had seven launches, each a success. The rocket launched the Chandrayaan-2 and -3 missions.
The rocket underwent many reevaluations and modifications with multiple safety redundancies, strengthening of structures and components, new and additional navigation systems, etc.
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Tests and updates
As a part of the Gaganyaan mission, ISRO has conducted several successful tests, making steady progress.
In December 2014, a decade ago, ISRO built a prototype — a smaller, skeletal version of the crew capsule — and performed an atmospheric re-entry test. The Crew Module Atmospheric Re-entry Experiment, or CARE programme, tested the module’s heat shields and overall resilience during the dangerous and fiery re-entry into the Earth’s atmosphere. The module also performed orientation manoeuvres to help decide the correct angle for entering the atmosphere.
A rocket carried the crew module to nearly 125 km and dropped it. Parachutes then slowed the capsule down before it fell into the ocean. The test was a success. The capsule, recovered from the Bay of Bengal overlooking the Sriharikota launch pads, was structurally sound.
In July 2018, ISRO conducted a pad abort test, which tested the abort system during launch time and the crew escape system. A launch abort during an emergency removes the crew module from the launch vehicle, and ejects it far away for safety. The successful four-minute test saw the ejection of the crew module when the rocket reached a height of 2.75 km. Once again slowed down by parachutes, the crew module safely landed in the Bay of Bengal.
In July 2021, ISRO performed successful Vikas engine firing tests.
In August 2023, the first parachute — referred to as a drogue parachute — was tested. The 5.8 m-wide parachute slowed down the accelerating crew module without the crew getting injured by shocks and changes in velocity.
There was a high-altitude abort test in October 2023. It was also a crew escape system test but much closer to launch and to the surface — just 15km off the ground. The test was successful, with the structurally sound module recovered from the Bay of Bengal.
The cryogenic engine was test-fired on 23 February this year.
There are a few more tests left before the mission can fly humans. There will be another test mission before the Gaganyaan test flight mission takes place later this year, likely in July.
Source:https://t.co/Dt3m97JjuX
— ISRO Spaceflight (@ISROSpaceflight) February 28, 2024
The orbital module will fly three times without humans to space and orbit Earth. Subsequently, the first human flight will likely happen late next year, creating history.
(Edited by Madhurita Goswami)
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