US space agency Nasa has launched a prototype rocket designed to replace the aging Shuttle fleet and one day to carry men back to the Moon.br br The Ares 1-X blasted off from Cape Canaveral in the southern US state of Florida for a journey that lasted just two minutes before it came down in the Atlantic Ocean.br br The flight may have been a short one but as Al Jazeeras John Terrett reports, a lot depends on Ares, including the future of Nasa itself.