Only hours after the successful return of the space shuttle Discovery, Nasa has had to delay one of its other space projects.Wednesday’s launch of the unmanned Mars Reconnaissance Orbiter has been postponed for at least 24-hours. The Orbiter’s mission is to learn whether Mars had water long enough to nurture life. Programme Manager, Doug McCuistion described the Mars Orbiter as “a weather satellite, a geological explorer and an explorational pathfinder”. The Orbiter will be carried into space via a Lockheed Martin Atlas V rocket. But engineers have found a problem with the navigational controls of a similar Atlas V launch vehicle and need to make sure the problem does not affect the one being used for the Mars spacecraft. The Orbiter is due to reach Mars in March 2006. During a series of orbits around the planet it will scan the surface and use an array of scientific instruments to zoom in for close-up photos. The launch is now scheduled, at the earliest, for Thursday morning.