Prime Minister Narendra Modi on Tuesday announced the names of the four astronauts for India's first manned space mission 'Gaganyaan'. The four astronauts are Group Captain P Balakrishnan Nair, Group Captain Ajit Krishnan, Group Captain Angad Pratap and Wing Commander S Shukla, PM Modi said at the Vikram Sarabhai Space Centre (VSSC) at Thumba near the Kerala state capital.