VENTURE STAR, the new single-stage-to-orbit replacement for the space shuttle, will be delayed by problems with the fuel tanks. The X-33 (a small-scale version of the eventual Venture Star) uses liquid oxygen and liquid hydrogen for fuel. The oxygen is contained in an aluminum tank, but the hydrogen was to be carried in graphite-epoxy composite tanks that would make up much of the structure of the spacecraft. But the graphite-epoxy tanks haven't worked out, showing serious leaks. If a decision is made to abandon the composite tanks and replace them with aluminum, it will delay the first flight of the X-33 from this summer into 2002. The flight was already a year behind schedule.--Stephen V Cole