Now nine minutes into the flight, Centaur's RL-10 engine continues to perform well.
Centaur Engine Performing Well

Now nine minutes into the flight, Centaur's RL-10 engine continues to perform well.
Image from NASA TV
Booster engine cut off and booster separation. The Centaur engine has taken over and will handle the rest of the job of delivering OSIRIS-REx to its release point. This is the first of two burns the Centaur will perform tonight. The payload fairing covering OSIRIS-REx has been jettisoned.
The single solid rocket booster has been jettisoned and the first-stage RD-180 engine continues to burn. Next major milestone: booster engine cutoff.
The rocket has passed Mach 1 and is now flying through Max Q.
Liftoff! The United Launch Alliance Atlas V rocket is climbing toward space with NASA's OSIRIS-REx spacecraft on a mission to boldly go to the asteroid Bennu — and back.
One minute to go. Eastern Range is ‘go.'
Two minutes remaining in the countdown. The Atlas V rocket is on internal power. The launch team's primary communications channels are quiet as the final minutes tick by.
When the countdown clock reaches zero, the Atlas V booster engine and single solid rocket booster ignite and the flight begins. The vehicle reaches Mach 1 after about 57 seconds, then flies through "Max Q," the area of maximum aerodynamic pressure, about 12 seconds later. The rocket's single solid rocket booster will be jettisoned after …
The countdown has resumed and there are four minutes remaining until the 7:05 p.m. liftoff of the United Launch Alliance Atlas V rocket carrying NASA's OSIRIS-REx spacecraft.