New Delhi: The Gaganyaan Mission is at a critical stage this year with three important missions scheduled for this year, ISRO Chairman Dr S Somanath said in an interview with NDTV.

"We are at a critical juncture with Gaganyaan this year. We have three important missions scheduled. First and foremost is the unmanned mission to orbit, spend time in orbit and return; the second is a test about equipment and algorithm; the third is a test to check the launch pad scenario," he said.

The space agency also has a manned mission in the pipeline for which four astronaut-designates have been named. Of them, only one would ultimately fly to space, Dr Somanath said, adding that the others will also be trained.

Speaking about a launch date, Dr Somanath said, "The first test flight of the Gaganyaan is scheduled for the end of next year if all goes well. But everything depends on the progress we are going to make."

The first Gaganyaan crewed flight may last one day in space with the astronaut doing 16 orbits of Earth, this would effectively test the environmental life support and control systems says Dr Somanath.

Prashanth Nair, Angad Prathap, Ajit Krishnan, and Shubhanshu Shukla are the four test pilots of the Indian Air Force who have been chosen for the Gaganyaan mission. The human space flight mission aims to launch a crew of up to three members into a Low Earth Orbit and bring them back after a missing lasting up to a week.

(With Reporting By NDTV)