April 26, 2019

Timeline: Atlas 5/WorldView 4 ascent profile


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This is the launch timeline to be followed by the Atlas 5 rocket’s ascent into orbit from Vandenberg Air Force Base in California with the commercial WorldView 4 Earth-imaging satellite for DigitalGlobe. Launch is scheduled for Friday at 10:30 a.m. local time (1:30 p.m. EST; 1830 GMT).

T+0:00:01.1: Liftoff
01
The United Launch Alliance Atlas 5 vehicle, designated AV-062, will lift off and begin a vertical rise away from Space Launch Complex 3-East at Vandenberg.

T+0:01:19.1: Mach 1 and Max Q
02
The Atlas rocket achieves Mach 1 some 79 seconds into the flight, then passes through the region of maximum dynamic pressure at 94 seconds.

T+0:04:03.1: Main Engine Cutoff
03
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+0:04:09.1: Stage Separation
04
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+0:04:19.0: Centaur Ignition No. 1
05
The Centaur RL10C-1 engine ignites for the longer of the two upper stage firings. This burn will inject the Centaur stage and WorldView 4 spacecraft into polar orbit.

T+0:04:27.1: Nose Cone Jettison
06
The two-piece, 14-foot-diameter payload fairing that protected the WorldView 4 spacecraft during the atmospheric ascent is separated to reveal the satellite to space.

T+0:15:36.9: Centaur Engine Cutoff No. 1
07
The Centaur engine shuts down after arriving in the planned sun-synchronous orbit of 379 by 390 miles tilted 97.96 degrees to the equator.

T+0:19:15.9: Spacecraft Separation
08
The high-resolution WorldView 4 imaging satellite is released into orbit from the Centaur upper stage to complete the primary objectives of the AV-062 launch.

T+2:11:45.9: Cubesat Separation
09
Seven tiny Cubesats being launched through a National Reconnaissance Office-sponsored rideshare, called the ENTERPRISE mission, are ejected from carriers mounted near the RL10 engine over a period of 14 minutes. The Centaur then executes another burn to escape Earth and enter solar orbit.

See earlier WorldView 4 coverage.

Our Atlas archive.


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