Endeavor Launch Trivia

From Neil deGrasse Tyson (@neiltyson)

Endeavor weighs 4.4million lbs. If engines gave only 4.4million lbs of thrust, forces would balance, leaving it afloat on pad

Endeavor gets 2.4million lbs of thrust **more** than its 4.4million lbs of weight, giving about 1/2 G acceleration on liftof

Most of the Shuttle's initial propulsion is to accelerate the mass of fuel that burns later in the launch.

Most of Shuttle's energy accelerates it horizontally rather than vertically. Go 17,200 mph sideways & you'd reach orbit too.

If camera-coverage enables, six cool things to look for just seconds before ignition of the SolidRocketBoosters...
1) Orbiter's steering flaps jiggle back and forth -- a final reminder that they can angle the way they're supposed to.
2) The Orbiter's 3 rocket nozzles gimbal to & fro -- a final reminder that they can aim the way they're supposed to.
3) Sparks spray onto launch pad -- they burn away any potentially flammable hydrogen gathered there from the main engine.
4) Water Tower dumps a swimming-pool's worth onto the launch pad -- H2O absorbs sound vibrations, preventing damage to craft
5) "Main Engine Start" -- Orbiter's 3 nozzles ignite, take aim, and force shuttle to tip forward. Bolts still hold her down.
6) "3 - 2 - 1 - Liftoff" -- SolidRocketBoosters ignite, tipping Shuttle straight upwards again. Bolts explode. Craft ascends