The launch of NASA’s twin GRAIL spacecraft

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.

The nation’s existing Atlas and Delta launch sites are vying for a future when United Launch Alliance completes its modernization with a new rocket system and downsizing to one pad on each coast.

Mars Pathfinder Mission Director Tony Spear narrates a video describing the launch preparations for the Mars Pathfinder spacecraft and the Sojourner rover.