Photos: Atlas 5 rolls out for launch

SpaceX test-fired 27 main engines on a Falcon Heavy rocket Thursday in Florida, clearing a hurdle before installing three commercial communications satellites on the launcher for a mission to geostationary orbit later this month.

This zoomed-in shot shows SpaceX’s Falcon 9 rocket firing off launch pad 39A Thursday with the U.S. military’s X-37B spaceplane.

Two astronauts floated outside the International Space Station Sunday for the first in a series of spacewalks to upgrade the lab’s aging solar power system, assembling a support fixture that eventually will hold a new solar blanket.