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CHEMISTRY IN FOCUS
Oxidation–Reduction Reactions Launch the Space Shuttle
Launching into space a vehicle that weighs millions
of pounds requires unimaginable quantities of energy—all furnished by oxidation–reduction reactions.
Notice from Figure 7.8 that three cylindrical
objects are attached to the shuttle orbiter. In the
center is a tank about 28 feet in diameter and 154
feet long that contains liquid oxygen and liquid
hydrogen (in separate compartments). These fuels
are fed to the orbiter’s rocket engines, where they
react to form water and release a huge quantity of
energy.
nium perchlorate (NH4ClO4) and powdered aluminum mixed with a binder (“glue”). Because the
rockets are so large, they are built in segments and
assembled at the launch site as shown in Figure
7.9. Each segment is filled with the syrupy propellant (Figure 7.10), which then solidifies to a consistency much like that of a hard rubber eraser.
The oxidation–reduction reaction between the
ammonium perchlorate and the aluminum is represented as follows:
2H2 O2 S 2H2O energy
3NH4ClO4 1s2 3Al1s2 S Al2O3 1s2 AlCl3 1s2
3NO1g2 6H2O1g2 energy
Note that we can recognize this reaction as an oxidation–reduction reaction because O2 is a reactant.
Two solid-fuel rockets 12 feet in diameter and
150 feet long are also attached to the orbiter. Each
rocket contains 1.1 million pounds of fuel: ammo-
It produces temperatures of about 5700 F and 3.3
million pounds of thrust in each rocket.
Thus we can see that oxidation–reduction
reactions furnish the energy to launch the space
shuttle.
External fuel tank
(153.8 feet long,
27.5 feet in diameter)
Solid booster
Left solid
rocket
booster
Orbiter
vehicle
Right solid
rocket
booster
Space shuttle
main engines
78.06 feet
Space shuttle Discovery
stacked for launch
Figure 7.8
For launch, the space shuttle
orbiter is attached to two solidfuel rockets (left and right) and
a fuel tank (center) that supplies
hydrogen and oxygen to the
orbiter’s engines. (Reprinted with
permission from Chemical and
Engineering News, September
19, 1988. Copyright © 1988
American Chemical Society.)
Aft field joint
(point of failure in
Challenger's right booster)
Solid
propellant
149.16 feet long,
12.17 feet in diameter
Figure 7.9
The solid-fuel rockets are
assembled from segments to
make loading the fuel more
convenient. (Reprinted with
permission from Chemical and
Engineering News, September
19, 1988. Copyright © 1988
American Chemical Society.)
Figure 7.10
A rocket segment being filled
with the propellant mixture.
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