Looking Ahead at Countdown, Ascent

Launch of a SpaceX Falcon 9 rocket carrying NASA’s TESS spacecraft remains scheduled for 6:51 p.m. EDT from Space Launch Complex 40 at Florida’s Cape Canaveral Air Force Station. Follow the countdown here and on www.nasa.gov/live starting at 6:30 p.m.

TESS is sealed inside the protective payload fairing atop its ride into space: the two-stage SpaceX Falcon 9 rocket. On the rocket’s first stage are nine Merlin engines; its second stage, which takes over the launch effort about two and a half minutes into the flight, is powered by a single Merlin engine. Both stages run on a combination of liquid oxygen and RP-1, a rocket-grade kerosene.

Here’s a look at the timeline for the final minutes of the count and the climb to orbit (times are approximate):

-00:07:00 — Falcon 9 begins engine chill prior to launch
-00:01:00 — Flight computer commanded to begin final prelaunch checks
-00:01:00 — Propellant tank pressurization to flight pressure begins
-00:00:45 — SpaceX Launch Director verifies go for launch
-00:00:03 — Engine controller commands engine ignition sequence to start
-00:00:00 — Liftoff
00:01:18 — Max Q (peak mechanical stress on the rocket)
00:02:30 — First stage main engine cutoff (MECO)
00:02:30 — First stage jettison
00:02:36 — Second stage engine starts
00:08:18 — Second stage engine cutoff (SECO 1)
00:43:06 — Second stage ignition 2
00:44:00 — Second stage engine cutoff (SECO 2)
00:49:30 — Spacecraft separation
00:57:11 — Begin solar array deployment (8 minutes, 28 seconds after separation)