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C H E M I S T R Y I N F O C U S
Oxidation–Reduction Reactions Launch the Space Shuttle
Launching into space a vehicle that weighs millionsof pounds requires unimaginable quantities of ener-gy—all furnished by oxidation–reduction reactions.
Notice from Figure 7.8 that three cylindricalobjects are attached to the shuttle orbiter. In thecenter is a tank about 28 feet in diameter and 154feet long that contains liquid oxygen and liquidhydrogen (in separate compartments). These fuelsare fed to the orbiter’s rocket engines, where theyreact to form water and release a huge quantity ofenergy.
Note that we can recognize this reaction as an oxi-dation–reduction reaction because O2 is a reactant.
Two solid-fuel rockets 12 feet in diameter and150 feet long are also attached to the orbiter. Eachrocket contains 1.1 million pounds of fuel: ammo-
2H2 � O2 S 2H2O � energy
nium perchlorate (NH4ClO4) and powdered alu-minum mixed with a binder (“glue”). Because therockets are so large, they are built in segments andassembled at the launch site as shown in Figure7.9. Each segment is filled with the syrupy propel-lant (Figure 7.10), which then solidifies to a con-sistency much like that of a hard rubber eraser.
The oxidation–reduction reaction between theammonium perchlorate and the aluminum is repre-sented as follows:
It produces temperatures of about 5700 �F and 3.3million pounds of thrust in each rocket.
Thus we can see that oxidation–reductionreactions furnish the energy to launch the spaceshuttle.
� 3NO1g2 � 6H2O1g2 � energy3NH4ClO41s2 � 3Al1s2S Al2O31s2 � AlCl31s2
External fuel tank(153.8 feet long,27.5 feet in diameter)
Right solidrocketbooster
Space shuttlemain engines
78.06 feetSpace shuttle Discoverystacked for launch
Orbitervehicle
Left solidrocketbooster
Solid booster
Aft field joint(point of failure inChallenger's right booster)
Solidpropellant
149.16 feet long,12.17 feet in diameter
Figure 7.8For launch, the space shuttle orbiter is attached to two solid-fuel rockets (left and right) anda fuel tank (center) that supplieshydrogen and oxygen to theorbiter’s engines. (Reprinted withpermission from Chemical andEngineering News, September19, 1988. Copyright © 1988American Chemical Society.)
Figure 7.9The solid-fuel rockets are assembled from segments tomake loading the fuel more convenient. (Reprinted with permission from Chemical andEngineering News, September19, 1988. Copyright © 1988American Chemical Society.)
Figure 7.10A rocket segment being filledwith the propellant mixture.
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