Chris Riley travels to NASA's Jet Propulsion Laboratory in California to find out about the extraordinary propulsion systems of the future - how ion engines and solar sails will soon be propelling us past the edge of our Solar System and on into interstellar space. Kathy Sykes talks to Paul Murdin, director of the British National Space Centre, whose discovery of a 'dark star' in 1971 finally confirmed the existence of the black hole. Plus a look at how tonnes of debris make journeys in space incredibly perilous.