Astronauts gear up for space with tough Russian training Wearing helmets weighing 100 kilos, spinning in a centrifuge and exercising while weightless: Russian cosmonauts and astronauts from abroad have to undergo a gruelling training process before blasting off into space. A few weeks before his second flight into orbit, Russian cosmonaut Sergei Ryazansky, who spent five months on board the ISS is training for a spacewalk at famed Star City training centre, near Moscow.