Dead stars could be cosmic \'GPS\'

Dead stars could be the future of spacecraft navigation, replacing earth-based systems with a cosmic \"global positioning system,\" British researchers say. The European Space Agency has commissioned scientists at Britain\'s National Physical Laboratory and the University of Leicester to investigate the feasibility of using dead stars known as pulsars to navigate spacecraft in deep space. Such navigation currently relies on radio transmissions between a distant craft and a network of ground-stations on Earth, which with the large distances involved can take hours, days or even longer, affecting a spacecraft\'s ability to react rapidly according to its location. The scientists said they are exploring the use of X-rays from dead stars, called pulsars, to allow spacecraft to navigate autonomously. Pulsars are highly compact and rapidly rotating neutron stars that emit intense electromagnetic radiation observed as pulses that could make suitable sources for navigation using a technique similar to GPS. This could allow spacecraft to navigate autonomously without needing to communicate with Earth, researchers said. \"Using on-board X-ray detectors, spacecraft could measure the times of pulses received from pulsars to determine the position and motion of the craft,\" Setnam Shemar of the National Physical Laboratory said. \"The University of Leicester will use their experience in X-ray astronomy to come-up with potential designs of the device and NPL will develop timing and navigation algorithms to determine the potential accuracy of this technique,\" Shamar said in a laboratory release. Using pulsars as nature\'s own GPS in space might one day enable humanity to navigate far beyond the outer reaches of our solar system, the researchers said.