Photos: Atlas 5 rolls out for launch

Boeing said Wednesday it has turned down an offer from Aerojet Rocketdyne to buy United Launch Alliance, a Boeing-Lockheed Martin joint venture that operates the Atlas and Delta rocket fleets.

Watch the pre-launch news conference held Monday, April 17 at NASA’s Kennedy Space Center to preview liftoff of the Orbital ATK commercial Cygnus OA-7 cargo ship aboard a United Launch Alliance Atlas 5 rocket for the International Space Station.

SpaceX called off the launch of a Falcon 9 rocket from Cape Canaveral on Wednesday to make sure the booster’s supply of super-chilled cryogenic liquid oxygen is cold enough to support the delivery of the 5.8-ton SES 9 commercial communications satellite to an orbit nearly 25,000 miles above Earth.