What to Expect After T-0

When the countdown clock ticks down to zero, the Atlas V’s first-stage engine and two solid rocket boosters will ignite, together generating about one and a half million pounds of thrust at sea level. The vehicle will go supersonic shortly before it flies through the area of maximum dynamic pressure, or “max Q,” about a minute and two seconds into the flight. The boosters burn out and jettison approximately two minutes after liftoff.

Just past the four-minute mark, several key events happen one after another in about 20 seconds: the Atlas booster engine cuts off, the Atlas and Centaur separate, the Centaur’s engine ignites, and the payload fairing is jettisoned. The Centaur engine will burn until 13-and-a-half minutes into flight. At that point, it performs its first cutoff, beginning a 59-minute coast phase.

Launch is scheduled for 10:44 p.m.