Video: Mars Pathfinder pre-launch preparations

Ground crews at Vandenberg Air Force Base in California retracted a mobile gantry away from the Delta 2 rocket Monday afternoon, revealing the 128-foot-tall (39-meter) booster on its launch pad awaiting liftoff with a new polar-orbiting weather observatory.

United Launch Alliance called off the launch of a Delta 2 rocket from California’s Central Coast early Tuesday after boats ventured into a restricted safety exclusion zone and engineers ran out of time to resolve a technical problem on the launcher.

A United Launch Alliance Delta 2 rocket climbed into space Saturday from California with a $1.6 billion polar-orbiting weather satellite for NOAA, the first of four upgraded observatories designed to keep vital meteorological data flowing to forecasters for the next two decades.