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Gaganyaan : India's Human spaceflight program

Updated: Jun 25


The main objective of the Gaganyaan mission is to demonstrate the capability of human spaceflight by launching a crew of 2-3 Vyomnauts to a lower Earth orbit (LEO) of 400 km for a 3 days mission and bring them safely to Earth, landing them in Indian waters. HRLV-3 (Human Rated Launch Vehicle Mark-3) the three-stage heavy-lift launch vehicle, will be used to launch Gaganyaan as it has the necessary payload capability. The successful completion of the mission would enhance India's status within the international space sector and serve as a catalyst for inspiring future generations to aspire towards extraterrestrial endeavours.

Gaganyaan Infographic

Key Components Of The Mission:

Various precursor missions are planned/completed for demonstrating the Technology Preparedness Levels before carrying out the actual Human Space Flight mission. These demonstrator missions include Integrated Air Drop Test (IADT), Pad Abort Test (PAT) and Test Vehicle (TV) flights.

1. Integrated Air Drop Test : 

The Gaganyaan Crew Module's parachute system includes 10 parachutes. During flight, the parachute deployment sequence begins with 2 Apex cover separation parachutes, which protect the Crew Module's parachute compartment. Next, 2 Drogue parachutes are deployed to stabilize and slow down the module. Once the Drogue parachutes are released, 3 Pilot chutes are used to individually deploy 3 Main parachutes, which further reduce the Crew Module's speed to safe levels for landing. Only 2 of the 3 Main parachutes are necessary for a safe landing, with the third serving as a backup. Performance testing for these parachutes involves complex methods, including Rail Track Rocket Sled (RTRS) tests for smaller parachutes and using aircraft or helicopters for the Main parachutes.

In the Integrated Main Parachute Airdrop Test, the system was tested under the condition where one Main parachute failed to open. This was the first in a series of tests to simulate various failure scenarios before the system is approved for use in manned missions. During the test, a 5-ton dummy mass, simulating the Crew Module, was dropped from a height of 2.5 kilometers using an Indian Air Force IL-76 aircraft. Two small pilot parachutes, deployed by pyrotechnic mortars, then pulled out the Main parachutes. These parachutes fully inflated and slowed the payload to a safe landing speed within 2-3 minutes, allowing it to land gently. 

Image shows 5 tonne mass simulator which is pulled out of Airplane for Integrated Air Drop Test of Parachute for Gaganyaan
5 Tonne platform extraction by extractor parachute | IMAT for Gaganyaan Mission. Image Credit : ISRO

2. Pad Abort Test:

A Pad Abort Test is a critical evaluation of the spacecraft's launch abort system, also known as the launch escape system. This system is engineered to rapidly extricate the crew and spacecraft from the launch vehicle in the event of an imminent failure. Analogous to an ejection seat in a fighter aircraft, which expels the pilot, the launch abort system propels the entire spacecraft away from the malfunctioning launch vehicle. The development and successful execution of this technology are integral to ensuring the safety of the first Indian crewed spacecraft, Gaganyaan.

3. Test Vehicle Flights:

TV-D1 was a high altitude abort test performed as part of the Gaganyaan  program. Main mission objectives are as follows:

  1. Flight demonstration and evaluation of the test vehicle subsystems at Mach number 1.2

  2. Flight demonstration and evaluation of the CES, including various separation systems

  3. Crew Module characteristics and demonstration of deceleration systems at higher altitude and its recovery

TV-D2 will be soon launching from Sriharikota to demonstrate a high altitude abort test for 2nd time in Supersonic condition at Mach Number 1.4 followed by TV-A1 at Maximum dynamic pressure condition and TV-A2 at Maximum Mach condition with Mach Number 2.2.

Gaganyaan Architecture

In the Gaganyaan mission architecture, the composite capsule comprises the Crew Module (CM) and the Service Module (SM), collectively referred to as the orbital craft. This integrated system features both an emergency mission abort mechanism and an emergency escape system, operable during the first or second stage of the launch vehicle's burn phase.

Interior View of Gaganyaan's Crew module and Service Module
Interior View of Gaganyaan's Crew module and Service Module

The Gaganyaan composite orbiter has a projected launch mass of approximately 7800 kg, with a dry mass of 3735 kg. The spacecraft is engineered with a double-walled structure and six semi-cylindrical outer panels to ensure thermal isolation from external thermal variations. The Crew Module, designed to accommodate 2–3 Vyomnauts, offers a habitable volume of about 8 cubic meters and maintains a controlled cabin environment. During the mission, the crew will conduct experiments in a microgravity environment.

The Service Module is outfitted with essential housekeeping elements, propulsion tanks, and instruments necessary for supporting the Crew Module, including life support and environmental control systems. Propulsion for the Service Module is provided by two bipropellant liquid engines. Electrical power is generated by two photovoltaic solar arrays, which are deployed post-injection. These arrays, in conjunction with lithium-ion batteries, deliver a power output of 5-6 kW.

Launch Vehicle:

GSLV Mk III, which is also referred as the Launch Vehicle Mark 3, LVM3's Human Rated version will be used to launch Gaganyaan. LMV-3 is designed to carry 4-ton class of satellites into Geosynchronous Transfer Orbit (GTO) or about 10 tons to Low Earth Orbit (LEO), which is about twice the capability of the GSLV Mk II.

GSLV Mk III is a three-stage heavy lift launch vehicle developed by ISRO. The vehicle has two solid strap-ons, a core liquid booster and a cryogenic upper stage. The two strap-on motors of GSLV Mk III are located on either side of its core liquid booster. Designated as ‘S200’, each carries 205 tons of composite solid propellant and their ignition results in vehicle lift-off. Strap-on function for 140 seconds. 

During the strap-on functioning phase, the two clustered Vikas liquid Engines of L110 liquid core booster will ignite 114 seconds after lift-off to further augment the thrust of the vehicle. These two engines continue to function after the separation of the strap-onsat about 140 seconds after lift-off.

Crew Escape System:

Space flight requires much higher velocities than air transportation, which in turn requires high energy density propellants. This results in dissipation of large amounts of energy to pass through the Earth’s atmosphere. Travelling in a rocket is like sitting on an exploding bomb, which will push your speed from 0 to over 25,000 km per hour in a few minutes. Anything may go wrong during the pre-launch, launch and post-phase, including the explosion of the rocket into a fireball. Launch escape system safety features have to be built to minimize the loss.

A Crew Escape System is therefore a crucial escape safety technology for Vyomnauts in an emergency/faulty mission situation. It ensures an advance warning of anything abnormal to the crew module and pulls it away to a safe distance. From there it can be landed either on sea or on land with the help of attached parachutes. Ejection seats carry Vyomnauts out of the capsule and away for individual parachute landing.

Challenges For The Gaganyaan Mission:

The Gaganyaan mission is so challenging because for the first time humans will be launched into space and must be brought back safely. In spite of taking care of every minuscule detail, there are always certain risks involved, such as:

Environmental Hazards: 

The space environment presents a multitude of hazards that pose significant challenges for human spaceflight. The absence of gravity, lack of atmosphere, and the omnipresent danger of radiation exposure, make space a hostile environment. These factors can lead to various medical issues for Vyomnauts, requiring advanced protective measures and medical interventions.


Transitioning from Earth's gravity to the microgravity environment of space has profound effects on the human body. The absence of gravity disrupts hand-eye and head-eye coordination, often causing Vyomnauts to lose their orientation and experience vision changes. Additionally, the lack of gravitational force leads to a significant decrease in muscle strength, aerobic capacity, and bone density. This is a serious concern, as bones lose minerals in microgravity, putting Vyomnauts at a higher risk of osteoporosis-related fractures. During spaceflights lasting five to eleven days, Vyomnauts can lose up to twenty percent of their muscle mass, which poses a severe risk, especially in the event of a landing emergency where physical strength is critical.

To counteract these detrimental effects, Vyomnauts must follow a strict regimen of exercise and diet. Regular physical activity is essential to maintain muscle mass and bone density, while a carefully planned diet helps in mitigating the loss of essential nutrients. Furthermore, the absence of atmospheric pressure in space can cause human blood to boil, a condition known as ebullism. Therefore, maintaining an acceptable atmospheric pressure inside the spacecraft is vital for the safety and well-being of the crew. Understanding these challenges and implementing effective countermeasures is crucial for the success of long-duration space missions and the health of Vyomnauts.

Sensory Systems:

During spaceflight, Vyomnauts are exposed to extreme environmental conditions that can significantly weaken their sensory systems, including hearing, sight, smell, taste, touch, the vestibular system (responsible for motion and equilibrium), and proprioception (the sense of the relative position of one’s body parts). These alterations in sensory perception can lead to a range of challenges, from difficulty in spatial orientation and balance to impaired communication and decreased enjoyment of food. Such sensory degradation not only impacts the physical capabilities of Vyomnauts but can also have profound effects on their mental health. The constant adaptation to altered sensory inputs, combined with the isolation and confinement of space travel, can contribute to stress, anxiety, and cognitive fatigue, highlighting the importance of addressing sensory health to ensure the overall well-being of Vyomnauts during missions.

Vyomnauts Training:

The Indian Vyomnauts will be addressed as “Vyomnauts”.  ISRO has signed a Memorandum of Understanding (MoU) with the Indian Air Force (IAF) for comprehensive crew management activities, encompassing cooperation in crew screening and selection, health management, and post-travel rehabilitation. The IAF, in consultation with ISRO, has developed an extensive roadmap for selecting and training future Vyomnauts for the Gaganyaan mission. While ISRO focuses on the mission's engineering aspects, science experiments will be conducted in collaboration with other organizations. The selection process, conducted in three phases, began with identifying 100 candidates based on specific criteria, including volunteers and individuals selected from flight engineers, pilots, fighter pilots, and experienced IAF test pilots. In the next phase, ten selected Vyomnauts underwent rigorous testing, including physical exercises, lab investigations, radiological and clinical tests, and psychological evaluations. Following intensive training at the Institute of Aerospace Medicine, only six of the ten Vyomnauts will advance to training with Roscosmos, which includes a module onboard a Soyuz spacecraft. Ultimately, only 2-3 Vyomnauts will be chosen to participate in India's first manned space mission.

Group Captain Prashanth Balakrishnan Nair, Angad Prathap, Ajit Krishnan and Shubanshu Shukla have been selected to be the Vyomnauts on India's first crewed mission to space.

Environmental Control and Life Support System:

In human spaceflight, the Environmental Control and Life Support System (ECLSS) plays a critical role in ensuring the safety and well-being of Vyomnauts. This sophisticated system supplies essential life-sustaining resources, maintains an acceptable living environment, and manages waste products. It also provides protection against harmful external influences such as radiation and micro-meteorites. The ECLSS is responsible for maintaining steady cabin pressure and optimal air composition, removing carbon dioxide and other hazardous gases, and regulating temperature and humidity. Additionally, it encompasses crucial functions such as fire detection and suppression, food and water management, and emergency support, thereby addressing a comprehensive range of parameters essential for the successful execution of space missions.

Re-entry and Recovery:

Upon re-entry into Earth's atmosphere, a spacecraft encounters extreme thermal loads, with temperatures soaring to several thousand degrees Celsius due to aerodynamic heating. This heating is a result of intense friction between the spacecraft and atmospheric particles, which can cause most meteoroids to vaporize before impact. Accurate control of the re-entry trajectory, including speed and angle, is critical; even minor deviations can result in mission failure. To mitigate thermal stress, spacecraft are equipped with advanced heat shields designed to withstand these severe conditions. Post re-entry, the descent module is programmed to land at a pre-determined maritime recovery zone, where naval or coast guard units can retrieve it.

The Crew Module Atmospheric Re-entry Experiment (CARE), an      integral component of India's Gaganyaan mission, served as a testbed for these technologies. Launched aboard the GSLV Mk III, the CARE module executed a planned re-entry approximately 20 minutes post-launch. It successfully deployed its parachutes during descent and performed a splashdown in the Bay of Bengal. Recovery operations were promptly conducted by the Indian Coast Guard, ensuring the module's safe retrieval for further analysis.

International Collaboration:

The Gaganyaan mission has seen significant international collaboration. Russia's space agency, Roscosmos, has been instrumental, providing extensive Vyomnaut training at the Gagarin Cosmonaut Training Center and assisting with life support and parachute systems. NASA has also contributed, offering technical exchanges, access to testing facilities, and insights from their human spaceflight experience, aiding in crew safety and mission planning.

The European Space Agency (ESA) has supported the mission by sharing expertise in space communication, navigation, and ground station support, ensuring robust communication and tracking capabilities. Additionally, France’s space agency, CNES, has helped with Vyomnaut training, medical support, and the development of the Environmental Control and Life Support System (ECLSS) for the crew module.

The United States has also contributed to the Gaganyaan mission, primarily through NASA. The collaboration with NASA has included technical exchanges and access to NASA’s facilities for testing and validation of systems. NASA's experience in human spaceflight has been invaluable, offering insights into crew safety, mission planning, and execution. This partnership has also extended to potential collaborations on future deep space missions.

Overall, the Gaganyaan mission's success is supported by these international collaborations, which bring together a wealth of knowledge, experience, and technology from leading space agencies around the world. These partnerships not only enhance the mission's technical capabilities but also foster a spirit of global cooperation in space exploration.


The Gaganyaan mission is a testament to India's growing capabilities in space technology and human spaceflight. It showcases the dedication and ingenuity of ISRO and marks a significant milestone in India's space exploration journey. With the successful execution of this mission, India will join the ranks of spacefaring nations with human spaceflight capabilities, opening new horizons for scientific research and international collaboration.

Here's Miscelleneous Information :

List of Products developed by DRDO which will be used in Gaganyaan Mission
List of Products developed by DRDO which will be used in Gaganyaan Mission

Thrusters for Gaganyaan Mission
Thrusters for Gaganyaan Mission

That's it for today. Hope you enjoyed reading. If so then do follow zetagravit on all platforms. Special Thanks to Rethik for providing images related to Gaganyaan. Article Written by Dhriti Sojitra and Edited by Parth Pandya. Thumbnail and Post is created by P Tharakaram, Produced by Team ZetaGravit.

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