Live coverage: 400th Proton rocket takes off with Russian satellite

A Russian Soyuz rocket has reached its last stop before liftoff Friday with two Russian cosmonauts and veteran NASA flight engineer Jeff Williams, who is slated to break the record for the most cumulative time spent in space by a U.S. astronaut.

Weather conditions at the surface will likely be favorable for the launch of a SpaceX Falcon 9 rocket Wednesday from Cape Canaveral, but upper level winds may pose a roadblock for the start of the company’s next space station resupply mission. SpaceX is targeting liftoff of the Falcon 9 from pad 40 at 12:51 p.m. EST (1751 GMT) Wednesday.

A Soviet-era missile originally built to deliver nuclear warheads to the United States in wartime fired into space for a much different purpose Tuesday, carrying a European environmental satellite into orbit to help track the effects of climate change.