Rocket Science for Earthlings
a continuing series for the gravitationally impaired. Rocket Science for Earthlings 1

Chapter 1, Mechanics

Three Hindus board a train in Delhi heading East at 10 mph. Four Klingons leave starbase 103 at warp 9.4 in a cloaked battle cruiser headed for Vulcan. If both vehicles enter a worm hole and collide, how many apples does Johnny have left? I always wanted to do that.

Velocity = Distance / Time. Which means, in space if you want to get somewhere, you either have to have the velocity or the time.

Acceleration = Velocity / Time. Acceleration determines how fast your velocity changes, which means that acceleration can speed things up or slow things down. In order to get the velocity to get somewhere in space you must accelerate. The standard for acceleration is the "g", based on earth's gravity. (9.8 m/s/s or 32 ft/s/s) This term also shows up in many other equations as a means to convert units.

Force = Mass * Acceleration. Now we're getting somewhere because rockets produce FORCE, and if the engine force is greater than the force of gravity holding the rocket on the pad, the rocket will rise. The force continues as the engine consumes the mass of the propellant, and the acceleration increases. Velocity accumulates as each second of acceleration adds more velocity, and the rocket streaks into space.

The high acceleration that rockets can produce has been used in several interesting manned vehicles. In 1928 the Opel-rak 2 rocket car used twenty four solid fueled rockets to attain a speed of 125 mph. Rocket sleds running on steel rails can reach speeds of mach 4. In the late forties Col. John Stapp made the rocket sled experiments famous by riding the sled himself to endure a 45g force. Stapp's experiments helped design ejection seats for supersonic aircraft.

Airplanes have also taken advantage of rocket acceleration. The W.W.II German ME-163 Comet was faster than any other fighter aircraft, and could only be shot down when it glided back to its base for a landing. The hydrogen peroxide monopropellant used in the Comet was very volatile and the aircraft was as deadly to its pilots as it was to Allied aircraft. The Bell X-1, X- 2, and the early versions of the X-15 all used four chambered liquid oxygen / alcohol engines built by Reaction Motors. The chambers could be lite one at a time to produce up to 6000 pounds of thrust. The 57,000 pound thrust XLR99 LOX / ammonia engine used in later X-15 flights was also built by Reaction Motors. This company was originally started as an amateur rocket group.

 Possibly the most unusual manned rocket vehicle use was the launching of combat ready F-104 Starfighters from a truck bed. With its engines at full throttle the F-104 achieved mach 1 almost immediately after launch. Pilots called the experience ACCELERATING.