United Launch Alliance technicians were allowed to return to the Atlas 5 pad Tuesday as firefighters continued to wage air and ground campaigns against the wildfire burning at Vandenberg Air Force Base in California.

United Launch Alliance will need to lure commercial customers to ensure the economic viability of its new Vulcan rocket, which is set to debut in 2019 just as the rate of U.S. military satellite launches is due to take a dip.

The Delta 4 rocket to launch the next Global Positioning System satellite to sustain the orbiting navigation network has been rolled out to the launch pad.