By Venkatachari Jagannathan Chennai, April 3 : The four Indian astronauts returned to India last month after completing their training in Russia and will undergo different kinds of training here, Indian Space Research Organisation (ISRO) chief K. Sivan said. "They had landed in India on March 28. The four astronauts will undergo space mission specific training in India," Sivan told IANS. The four Indian astronauts were training since February 2020 at the Gagarin Cosmonaut Training Centre (GCTC) belonging to Glavkosmos which is a subsidiary of Russian space corporation Roscosmos. According to Sivan, the four astronauts will continue to train till they board the Indian space module. The Rs 10,000 crore Indian human space flight mission is called Gaganyaan. Queried about the training regime here, Sivan said: "The astronauts will have their physical fitness training that includes swimming, jogging. They will also have academic/theoretical classes as they have to understand the rocket, and the human space module." "They will also be trained on simulators. The Gaganyaan module navigation terminals will be simulated. The astronauts will be trained on various parameters that will be displayed on the terminals," he added. The astronauts will later work on the Gaganyaan module as if they are flying. "These apart, the astronauts will be trained on survival techniques so that they can survive in the sea as their landing module will land on the sea waters," Sivan said. While the astronauts will be trained in Bengaluru and the survival techniques in Cochin, ISRO will carry out the engineering work related to Gaganyaaan. Glavkosmos had earlier said the four Indian astronauts were trained in abnormal descent module landing - in wooded and marshy areas in winter; on water surface, and in the steppe in summer. "In June 2020, all Indian astronauts-elect passed training in short-term weightlessness mode aboard the IL-76MDK special laboratory aircraft, and in July, they were trained to lift aboard a helicopter while evacuating from the descent module landing point," Glavkosmos had said. The Indian fighter pilots were also trained in a centrifuge and in a hyperbaric chamber to prepare their organisms for sustaining spaceflight factors, such as G-force, hypoxia and pressure drops. The regular courses comprise medical and physical training, learning Russian (as one of the main international languages of communication in space), and studying the configuration, structure and systems of the Soyuz crewed spacecraft, Glavkosmos had said. Sivan said the Indian space agency is targeting the first unmanned space flight in December 2021. (Venkatachari Jagannathan can be contacted at v.jagannathan@ians.in) /IANS