Atlas/MMS launch timeline

CAPE CANAVERAL — This is the ascent timeline to be followed by the United Launch Alliance Atlas 5 rocket in launching NASA’s MMS mission on March 12 at 10:44 p.m. EDT.

T+0:00:00.0    Liftoff
Atlas AV-011 Launch
With the RD-180 main engine running, the twin strap-on solid rocket boosters are lit as the Atlas 5 vehicle lifts off and begins a vertical rise away from Complex 41 at Cape Canaveral Air Force Station, Florida.

T+0:01:02.5: Max Q


The Atlas rocket passes through the region of maximum dynamic pressure during ascent through the lower atmosphere.

T+0:02:18.6    Jettison SRBs


Having burned out of propellant approximately 45 seconds earlier, the spent solid rocket boosters are jettisoned to fall into the Atlantic Ocean.

T+0:04:09.7    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+0:04:15.7    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+0:04:25.7    Centaur Ignition 1


The Centaur RL10 engine ignites for the first of two upper stage firings. This burn will inject the Centaur stage and MMS spacecraft into an initial parking orbit.

T+0:04:33.7    Nose Cone Jettison


The payload fairing that protected the MMS spacecraft during launch is separated once heating levels drop to predetermined limits after passage through the atmosphere.

T+0:13:29.0    Centaur Cutoff 1


The Centaur engine shuts down after arriving in a planned low-Earth parking orbit. The vehicle enters a 59-minute coast period before arriving at the required location in space for the second burn.

T+1:12:29.8    Centaur Ignition 2


A final push by Centaur is ignited to raise the orbit for the MMS spacecraft into a highly elliptical Earth orbit.

T+1:18:11.3    Centaur Cutoff 2


The powered phase of flight is concluded as the Centaur reaches the planned orbit of 316 by 37,886 nautical miles and 28.77 degrees inclination.

T+1:32:11.3    MMS-4 Separation


The first Magnetospheric Multiscale observatories is separated into orbit.

T+1:37:11.3    MMS-3 Separation


The second Magnetospheric Multiscale observatories is separated into orbit.

T+1:42:11.3    MMS-2 Separation


The third Magnetospheric Multiscale observatories is separated into orbit.

T+1:47:11.3    MMS-1 Separation


The fourth Magnetospheric Multiscale observatories is separated into orbit from the Centaur upper stage to complete the launch.