Live coverage: Cygnus supply ship captured by space station robot arm

The second fully commercial astronaut flight to the International Space Station will have just two opportunities to launch Sunday and Monday, or else wait until after an upcoming SpaceX resupply mission next month to deliver a new set of high-priority solar arrays to the complex.

A United Launch Alliance Atlas 5 rocket, flying in its basic two-stage configuration with no strap-on solids, was stacked aboard a mobile launch platform at Cape Canaveral’s Vertical Integration Facility on Feb. 22 and 23 in preparation to send Orbital ATK’s S.S. John Glenn cargo ship into orbit for the International Space Station.

A Soyuz rocket is standing on the launch pad in Kazakhstan used on Yuri Gagarin’s historic first human spaceflight in 1961, ready to send three people toward the International Space Station.