NASA has delayed the launch of the space shuttle Discovery by 24 hours to allow more time to review data about a suspect valve in the liquid hydrogen fuel tank, dpa cited officials as saying today. NASA earlier this week scrubbed a Tuesday launch to the early hours of Friday morning after detecting a problem with the fill and drain valve. The latest plan is to proceed with the launch about midnight Friday (0400 GMT Saturday). NASA said more time was needed to determine whether the problem lies with the valve or a gauge that was showing the valve to be open when it was supposed to be closed. Fuel valve problems have dogged recent shuttle launches as the ageing craft and launch apparatus enters the final phase of the decades-old shuttle programme. By late next year, NASA hopes to have completed the build-out of the orbiting International Space Station so it can retire the shuttles. In their place, a new spacecraft is being built that will be available in 2015 at the earliest. Delayed takeoffs are common with space shuttle missions. The last shuttle to blast off, Endeavour, only did so in July after five scrubbed missions due to technical problems and bad weather. The current planned 13-day mission is designed to transport new equipment and experiments to the International Space Station (ISS). Astronaut Nicole Stott is expected to relieve Timothy Kopra aboard the ISS, and three spacewalks are planned for the mission. Discovery's crew for this mission includes six Americans and Swede Christer Fuglesang, flying for the European Space Agency.