(Editor’s note: Times will vary slightly depending on when liftoff occurs during the two-hour daily launch window.)
T+00:01.1: Liftoff
The United Launch Alliance Atlas 5 vehicle, designated AV-067, will lift off and begin a vertical rise away from Complex 41 at Cape Canaveral Air Force Station, Florida.
T+00:57: Mach 1 and Max Q
The Atlas rocket achieves Mach 1 some 57 seconds into the flight, then passes through the region of maximum dynamic pressure at 69 seconds.
T+02:19 Jettison SRB
Having burned out of propellant approximately 50 seconds earlier, the spent solid rocket booster is jettisoned once dynamic pressure conditions are satisfied.
T+04:03: Main Engine Cutoff
The RD-180 main engine completes its firing after consuming the load of RP-1 kerosene fuel and liquid oxygen supply in the Atlas first stage.
T+04:09: Stage Separation
The Common Core Booster first stage of the Atlas 5 rocket separates from the Centaur upper stage. Over the next few seconds, the Centaur engine liquid hydrogen and liquid oxygen systems are readied for ignition.
T+04:19: Centaur Ignition No. 1
The Centaur RL10 engine ignites for the longer of the two upper stage firings. This burn will inject the Centaur stage and OSIRIS-REx into an Earth parking orbit.
T+04:27: Nose Cone Jettison
The two-piece, 14-foot-diameter payload fairing that protected the OSIRIS-REx spacecraft during the atmospheric ascent is separated to reveal the satellite to space.
T+12:23: Centaur Engine Cutoff No. 1
The Centaur engine shuts down after arriving in its planned temporary orbit around the Earth. The vehicle enters a brief coast period before reaching at the required location in space for the second burn.
T+33:48: Centaur Ignition No. 2
The Centaur re-ignites to propel OSIRIS-REx on the outbound leg of its journey to Asteroid Bennu.
T+40:39: Centaur Engine Cutoff No. 2
At the conclusion of its second firing, the Centaur will have delivered the necessary velocity for OSIRIS-REx to achieve an Earth-escape trajectory.
T+55:39: Spacecraft Separation
NASA’s OSIRIS-REx asteroid sample return mission is released from the Centaur upper stage to begin its solo flight to Bennu, completing the AV-067 launch.
See earlier OSIRIS-REx coverage.
Our Atlas archive.
from Spaceflight Now ift.tt/2cdigDG
