Video: Liftoff of Atlas 5 on space station cargo mission

The United Launch Alliance Atlas 5 rocket, standing 197 feet tall and and weighing 1.2 million pounds, unleashes 2.4 million pounds of thrust from its main engine and four solid-fuel boosters at 6:42 p.m. EST (2342 GMT) Saturday to launch the GOES-R weather observer for NASA and NOAA from Cape Canaveral, Florida.

A European-built Ariane 5 rocket rolled out to a launch pad in the South American jungle Wednesday with a pair of commercial television broadcast satellites for AT&T and Eutelsat, setting the stage for liftoff Thursday evening.

Receiving a boost from a modified decades-old Peacekeeper missile originally built for nuclear war, a U.S. military space surveillance satellite streaked into space early Saturday from Cape Canaveral to help the Air Force track threats and debris in orbit.