Photos: Atlas 5 rolls out for launch

Delays have set up the possibility of up to three rocket launches this weekend from different pads along Florida’s Space Coast, including two SpaceX missions on Sunday that could set a company record for the shortest span between two Falcon 9 rocket launches. But in the world of ever-changing launch schedules, numerous factors such as weather and technical issues could thwart launch plans this weekend. 

Another countdown for United Launch Alliance’s next Delta 4-Heavy rocket mission ended without a liftoff Wednesday after a computer sequencer detected a potential problem just before engine ignition.

NASA’s OSIRIS-REx spacecraft today moved a step closer to starting a voyage to explore an uncharted world in our solar system — the mountain-sized Asteroid Bennu — by joining the booster rocket that will propel it from Earth next week.