Video: Soyuz capsule docks to the International Space Station

Investigators believe a leak of propellant inside the Crew Dragon spacecraft’s propulsion system led to the capsule’s explosion April 20 during a ground test at Cape Canaveral, and a senior SpaceX official said Monday that delays are making it “increasingly difficult” to fly astronauts on the commercial spaceship before the end of the year.

Photos released by Russia’s space agency show the launch of a Soyuz booster Wednesday from the Baikonur Cosmodrome in Kazakhstan with two Russian cosmonauts and a NASA astronaut heading for the International Space Station.

A United Launch Alliance Atlas 5 rocket blasted off from Cape Canaveral at 11:05 p.m. EDT (0305 GMT) tonight to send Orbital ATK’s commercial Cygnus cargo freighter to the International Space Station. Follow the mission in our live journal.