Video: Take a virtual ride on the Atlas 5 launch pad emergency ziplines

Ground crews finished the initial build-up of the last “single stick” medium-lift variant of United Launch Alliance’s Delta 4 rocket on its launch pad at Cape Canaveral last week in preparation for liftoff with a GPS navigation satellite July 25.

A day after a timing error caused it to enter the wrong orbit and miss its objective of meeting up with the International Space Station, Boeing’s unpiloted Starliner crew capsule prepared for its next major test Sunday, when it will plunge back into the atmosphere and target a predawn landing at White Sands Space Harbor in New Mexico.

The White House’s $19.9 billion NASA budget outline released Monday would continue development of NASA’s heavy-lift Space Launch System rocket and Orion crew capsule and begin the deployment of a mini-space station around the moon as soon as 2022, but the proposal would cancel WFIRST, a flagship-class astronomy mission planned for launch in the mid-2020s.