Delta 4 launch seen from press viewing site (members only)

A United Launch Alliance Atlas 5 rocket emerged from its vertical hangar Tuesday for the 1,800-foot journey to pad 41 at Cape Canaveral Air Force Station, moving into position for liftoff Thursday with NASA’s Mars 2020 Perseverance rover.

The Global Positioning System, its precision navigation and timing services made possible by the U.S. Air Force and provided free-of-charge to the planet’s civilian population, is a marvel of the modern world, and the orbiting network will receive a fresh satellite Wednesday.

An Ariane 5 rocket and four Galileo navigation satellites launched from French Guiana at 1125 GMT (7:25 a.m. EDT), beginning a four-hour climb into orbit more than 14,000 miles above Earth.