The Indian Space Research Organisation (ISRO) has picked the youngest of its astronaut-designates as the prime astronaut to fly on the upcoming Indo-US mission to the International Space Station (ISS).

Group Captain Shubhanshu Shukla who recently got promoted has been selected as the prime astronaut.

A 'prime astronaut' is chosen to fly, but a backup astronaut is always kept as a last-minute swap option in case of any mishap.

Shukla was born in Uttar Pradesh's Lucknow on October 10, 1985. He is an alumnus of the National Defence Academy and was commissioned on June 17, 2006 in the fighter stream of the Indian Air Force (IAF).

He is a Fighter Combat Leader and a test pilot with approximately 2,000 hours of flying experience. He has flown various aircraft, including Sukhoi-30MKI, MiG-21, MiG-29, Jaguar, Hawk, Dornier, and An-32.

The backup astronaut will be Group Captain Prasanth Balakrishnan Nair, the oldest of the astronaut-designates. He was born in Kerala's Thiruvazhiyad on August 26, 1976. He is also an alumnus of the National Defence Academy and a recipient of the Sword of Honour at the Air Force Academy. He was commissioned on December 19, 1998 in the fighter stream of the IAF.

Group Captain Nair is a Category-A flying Instructor - the highest that a pilot can achieve, and a test pilot with approximately 3,000 hours of flying experience. He has also flown several aircraft including Sukhoi-30MKI, MiG-21, MiG-29, Hawk, Dornier, and An-32.

He is an alumnus of the United States Staff College and a Directing Staff at Defence Services Staff College, Wellington, and the Flying Instructors School, Tambaram.  He has commanded a Sukhoi-30MKI squadron.