Ali said for the first human spaceflight, planned for launch late next year, four Indian Air Force pilots have been selected

India's Gaganyaan mission will not be a "one-off" mission as the government has granted approval for a "sustained human space flight program", a senior ISRO official said on Saturday.

Addressing the 'Be Inspired: Festival of Ideas' event here, Imtiaz Ali Khan, director of ISRO's Directorate of Human Spaceflight Program, said the follow-on space missions of Gaganyaan may include civilians such as doctors and scientists.

Ali said for the first human spaceflight, planned for launch late next year, four Indian Air Force pilots have been selected and were undergoing extensive training for the mission.

“Gaganyaan will not be a one-off mission as the government has given us approval for a sustained human spaceflight (HSF) program,” Ali said, adding that the future missions will be decided after ISRO demonstrates its capabilities by carrying out India's first successful human spaceflight.

He said the kind of benefit one expected from the HSF program requires a longer stay in microgravity and there was a need to develop new technologies such as rendezvous, docking among others.

Ali said the subsequent missions will have non-pilot people, including civilians, women, doctors, and scientists drawn from different fields for carrying out science experiments in outer space.

He said age was not a very strict criterion for undertaking space missions as the person has to be agile, fit, able to understand procedures and work well on simulators during the training sessions.

ISRO plans to send at least two astronauts into a low-earth orbit in 2024 after assessing the outcome of the two orbital test flights.

Last week, ISRO completed the final long-duration hot test of the human-rated L110-G Vikas engine, a major achievement in the development of the Gaganyaan human spaceflight program.

Prime Minister Narendra Modi announced the Gaganyaan mission in his Independence Day address in 2018 at a cost of Rs 10,000 crore.