The Indian trip to the International Space Station (ISS) is meant to offer a practical learning experience and serve as a precursor to India's own effort to send astronauts to space and return them safely - an ambitious mission known as 'Gaganyaan'

Forty years after Indian Air Force Pilot and Astronaut Rakesh Sharma flew to space and stayed there for a week (as part of the Soviet Interkosmos program), Indian astronauts are to commence training for a trip to the International Space Station (ISS), as part of a US-led mission. Expected to happen in 2024, the Indian trip to the International Space Station (ISS) is meant to offer a practical learning experience and serve as a precursor to India's own effort to send astronauts to space and return them safely - an ambitious mission known as 'Gaganyaan'. So far, astronauts from more than 20 nations have visited and stayed at the ISS, a space-based lab that has been orbiting the Earth (at an altitude of 400 km) for more than 25 years.

Starting the New Year with a successful launch mission PSLV-C58/XPoSat, Dr S Somanath, the chief of the Indian space agency said, 2024 would be the year of Gaganyaan preparedness. "Our target is to carry out the astronaut mission by 2025-end, for that we have to cross many milestones. Some of the milestones are three unmanned flights (full rehearsals) of the Human spaceflight mission but without the astronauts. In 2024, we have scheduled two unmanned missions and everything should go well," he said.

In the unmanned flights, ISRO would be flying a humanoid robot 'Vyommitra', designed and developed by the ISRO Inertial Systems Unit (IISU). The AI-equipped humanoid robot, onboard computers, and a host of sensors would offer ISRO situational awareness about the conditions within the astronaut-carrying capsule that's going to space and returning.

In October 2023, ISRO had flight tested the Crew Escape System (a mission designated TV-D1), a means of ejecting the crew capsule from the rocket, in case of a mid-flight failure, thereby ensuring a slow and safe parachute-assisted landing in the ocean. ISRO hopes to perform three more such tests, under varying conditions. Two of these are expected in 2024 and one in 2025.

In addition to these, ISRO would have to conduct helicopter-drop tests of the crew-carrying capsule, to validate the parachute systems and also conduct a Pad-abort test, which ejects the crew-carrying capsule from the rocket, in case of a mishap while the rocket is at the launchpad. Overall, 2024 would be a year where ISRO would have to carry out routine launch missions of its operational rockets (SSLV, PSLV, GSLV and LVM3), while also developing and engineering key technologies related to the Gaganyaan mission.

In recent years, Indian astronaut candidates (specifically chosen Indian Air Force pilots) have completed their initial training at the Gagarin Cosmonaut Training Centre, in Russia. They were at the famed Russian 'Star City', about 30 kilometres north of Moscow, where several generations of Russian and American astronauts have trained for their respective missions. After their return to India, the astronaut candidates have also undergone several theoretical and practical sessions at ISRO centres in India and the Indian Air Force's Institute of Aerospace Medicine. As a part of the Gaganyaan team, they are also assisting ISRO with the design and development of the crew-carrying capsule. At India's Human Spaceflight Centre in Bengaluru, they have also been undergoing simulator training and physical training

Queried about the commencement of the US phase of training for the Indian astronauts, Dr Somanath told WION that it will happen soon. He told WION that it is on India's wish list to have an astronaut flying to the International Space Station (ISS), as India's only reference point for Human Spaceflight is that of Wing Commander Rakesh Sharma (Retd), who flew in 1984. That maiden spaceflight by an Indian was on a Soviet-era crew capsule and since then the technologies have changed drastically.

"The US Human spaceflight scenario is completely changed and the launches are being carried out by the private firms and it is not being done by the US Government, as was the case earlier. As per the India-US (ISRO-NASA) arrangement, NASA will sponsor a seat in the private launch that will happen to the ISS, our astronaut will undergo training at their facility and will then be sent to the International Space Station," he said.

He added that there are many crew modules and different approaches being taken by various American firms to reach the Space Station. He referred to the SpaceX Crew Dragon Capsule, the Boeing Starliner capsule and the variant offered by Blue Origin.

Indian astronaut candidates would be offered advanced training at NASA's Johnson Space Centre, which is also known in the US as the Hub of Human Spaceflight. Established in 1961, this facility in Houston, Texas, started off as the Manned Spacecraft Centre, the home and Mission Control Centre for the US Human Spaceflight programme. In 1973, the facility was renamed in honour of the late President and Texas Native Lyndon B Johnson. In more than six decades of operation, the facility has made notable advances in science, technology, engineering and medicine, thereby enabling crewed space exploration.

Significant initiatives towards Indo-US Space Cooperation were announced during the Joint Statement delivered by Prime Minister Modi and President Biden, in June 2022. It included the announcement by NASA to provide advanced training to Indian astronauts at the Johnson Space Center in Houston, Texas, with a goal of mounting a joint effort to the International Space Station in 2024.

So far, the identities of the four Indian astronaut candidates have not been revealed. The only glimpse offered in this regard is from an Indian Air Force video released as part of the 91st IAF Day celebrations.