2. A rocket is a machine that develops
thrust by the rapid expulsion of
matter. The major components of a
chemical rocket assembly are a
rocket motor or engine,
propellant consisting of fuel and an
oxidizer, a frame to hold the
components, control systems and a
cargo such as a satellite

3. THRUST
Is the force generated, measured in pounds or
kilograms. Thrust generated by the first stage
must be greater than the weight of the
complete launch vehicle while standing on the
launch pad in order to get it moving. Once
moving upward, thrust must continue to be
generated to accelerate the launch vehicle
against the force of the Earth's gravity. To
place a satellite into orbit around the Earth,
thrust must continue until the minimum
altitude and orbital velocity have been
attained or the launch vehicle will fall back to
the Earth. Minimum altitude is rarely
desirable, therefore thrust must continue to
be generated to gain additional orbital
altitude.

4. The IMPULSE
sometimes called total
impulse, is the product of
thrust and the effective firing
duration. A shoulder fired
rocket such as the LAW has
an average thrust of 600 lbs
and a firing duration of 0.2
seconds for an impulse of
120 lb-sec. The Saturn V
rocket, used during the
Apollo program, not only
generated much more thrust
but also for a much longer
time. It had an impulse of
1.15 billion lb-sec.

5. A rocket in its simplest form is a chamber
enclosing a gas under pressure. A small
opening at one end of the chamber allows
the gas to escape, and in doing so
provides a thrust that propels the rocket
in the opposite direction. A good example
of this is a balloon. Air inside a balloon
is compressed by the balloon's rubber
walls. The air pushes back so that the
forces on each side are balanced. When
the nozzle is released, air escapes through
it and the balloon is propelled in the
opposite direction.
With space rockets, the gas is produced by
burning propellants that can be solid or
liquid in form or a combination of the
two.

6. There are several Different Types
of rocket. The following articles
contain lists of rockets by type:
List of missiles
List of orbital launch systems
List of sounding rockets
List of unguided rockets
List of upper stages