Space
Shuttle Basics
Second
Stage Ascent
The three space
shuttle main engines, attached to the rear of the shuttle orbiter,
continue to fire until about 8.5 minutes after liftoff, burning
a half-million gallons of liquid propellant from the large, orange
external fuel tank as the shuttle accelerates. The main engines
burn liquid hydrogen — the second coldest liquid on Earth at minus
252.7 degrees Celsius (minus 423 degrees Fahrenheit) — and liquid
oxygen. Since the hydrogen and oxygen can reach a temperature as
high as 3,315.6 degrees Celsius (6,000 degrees Fahrenheit) as they
burn — higher than the boiling point of iron — the engines operate
at greater temperature extremes than any other piece of machinery
ever built.
 | | The
three space shuttle main engines propel the spacecraft into
orbit for eight minutes and forty seconds after launch. |
The engines'
exhaust is primarily water vapor as the hydrogen and oxygen combine.
As they push the shuttle toward orbit, the engines consume the liquid
fuel at a rate that would drain an average family swimming pool
every 25 seconds and they generate over 37 million horsepower. Their
turbines spin almost 13 times as fast as an automobile engine spins
when it is running at highway speed.
Eight and a
half minutes after launch, with the shuttle traveling 8 kilometers
(5 miles) a second, the engines shut down as they use the last of
their fuel. A few seconds after the engines stop, the external fuel
tank is jettisoned from the shuttle. The only part of the shuttle
that is not reused, the tank re-enters the atmosphere and burns
up over the Pacific Ocean. The shuttle orbiter, the only space shuttle
component that will circle the Earth, weighs only about 117,934
kilograms (260,000 pounds). The shuttle has consumed more than 1.59
million kilograms (3.5 million pounds) of fuel during its first
8 ½ minutes of flight. |
