The launch of NASA’s twin GRAIL spacecraft

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.

A Delta 2 rocket lifted off from California’s Central Coast Saturday after back-to-back scrubbed launch attempts earlier this week. The Delta 2 delivered the JPSS 1 weather satellite to orbit for NOAA.

The final flight of a Delta 2 rocket, a mainstay of the U.S. launch industry for nearly 30 years, began at 6:02 a.m. PDT (9:02 a.m. EDT; 1302 GMT) from Vandenberg Air Force Base in California with NASA’s ICESat 2 Earth science satellite.