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.
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.