Live coverage: Atlas 5 countdown and launch journal

Engineers scrambled to keep NASA’s billion-dollar asteroid-bound OSIRIS-REx spacecraft on track for its launch last week in the aftermath of an explosion a mile away at SpaceX’s launch pad at Cape Canaveral.

NASA awarded Northrop Grumman a contract worth as much as $84.5 million earlier this month to supply rocket motors for a first-of-its-kind launch vehicle to fire a capsule of rock samples off of Mars on a journey back to Earth.

This is the pre-launch news conference held Dec. 2 at NASA’s Kennedy Space Center for liftoff of the Orbital ATK commercial Cygnus cargo ship aboard a United Launch Alliance Atlas 5 rocket for the International Space Station.