Atlas 5/Solar Orbiter launch timeline

This is the launch timeline to be followed by the Atlas 5 rocket’s ascent into orbit from Cape Canaveral with the European-built Solar Orbiter spacecraft to study the sun.

Launch is scheduled 11:03 p.m. EST Sunday (0403 GMT Monday) at the opening of a two-hour launch window.

The 189-foot-tall (57.6-meter) rocket will arc to the southeast from Florida’s Space Coast on its first flight of the year. It will be the 82nd Atlas 5 launch overall since United Launch Alliance’s workhorse rocket debuted in August 2002.

The timeline below ends with the conclusion of the primary mission, the deployment of the Solar Orbiter spacecraft on an interplanetary escape trajectory into heliocentric orbit to begin its mission studying the sun.

Follow live coverage of the countdown and launch in our Mission Status Center.

T+00:00.0: Liftoff

With the RD-180 main engine running and single solid rocket booster firing, the Atlas 5 vehicle lifts off and begins a vertical rise away from Complex 41 at Cape Canaveral Air Force Station, Florida.

T+00:1:09: Max Q

The Atlas 5 rocket, after breaking the sound barrier at 58 seconds, passes through the region of maximum dynamic pressure during ascent through the lower atmosphere.

T+02:19.8 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+04:03.4 Main Engine Cutoff

The RD-180 main engine completes its firing after consuming its kerosene and liquid oxygen fuel supply in the Atlas first stage.

T+04:09.4 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+04:19.4 Centaur Ignition 1

The Centaur RL10C-1 engine ignites for the first of two upper stage firings. This burn will inject the Centaur stage and Solar Orbiter spacecraft into an initial parking orbit.

T+04:27.3: Nose Cone Jettison

The payload fairing that protected the Solar Orbiter spacecraft during launch is separated after passage through the atmosphere.

T+12:14.1: Centaur MECO 1

The Centaur engine shuts down after arriving in a planned low-Earth parking orbit. The vehicle enters a 10-minute coast period before arriving at the required location in space for the second burn.

T+42:57.9 Centaur Ignition 2

A final push by Centaur is ignited to accelerate the Solar Orbiter spacecraft to Earth escape velocity.


T+49:50.8 Centaur Cutoff 2

The powered phase of flight is concluded as the Centaur reaches a velocity of some 27,000 mph relative to Earth for deployment of the Solar Orbiter spacecraft.


T+52:39.9 Spacecraft Separation

The Airbus Defense and Space-built Solar Orbiter spacecraft deploys from the Centaur upper stage on a trajectory entering a heliocentric orbit around the sun.