Watch live: Orbital Sciences' Antares rocket to lift off on test flight (update: success!)

SpaceX may be the only private outfit currently shepherding cargo to the International Space Station, but Orbital Sciences, which is the second party in NASA's Commercial Orbital Transportation Services effort, is taking a step towards its own ISS resupply missions. Today, the firm's Antares rocket will undergo its very first test flight, taking off from the space agency's Wallops Flight Facility on Wallops Island, Virginia. Liftoff is slated for sometime between 5PM and 7PM, with an 80 percent ...