Game Development Reference
In-Depth Information
CHAPTER 11
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Rockets and Missiles
I
n previous chapters in this topic, we explored how to model the motion of cars, boats, and
airplanes. Now it's time to leave the confines of the lower atmosphere and learn about the
physics of rockets. Rockets have been around for 800 years or so. At first they were used mostly
for military purposes, but starting in the twentieth century, people have used rockets to explore
the solar system or to put satellites into orbit.
In analyzing the physics of rockets, we will once again turn to the “four forces”—thrust,
drag, lift, and gravity. You will learn about the different types of rockets and rocket engines and
how they generate thrust. Because rockets can travel into the upper atmosphere and beyond,
we will explore how altitude affects gravity, thrust, and drag. We will use what we discuss about
rockets to create a rocket simulator that will model the flight of a rocket as it rises into the
atmosphere. Some of the other topics this chapter will cover include the following:
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A brief history of rockets
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A general force diagram of a rocket in flight
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The rocket equation and how it can be used to compute the velocity of a rocket
•
An introduction to planetary orbits
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How multistage rockets can be used to improve rocket performance
•
An introduction to modeling rocket-powered missiles
Let's start the rocket rolling with a brief history of rocketry.
A Brief History of Rockets
Some people think of rockets as being part of the Space Age, but they have actually been around
for a long time. The Chinese are generally credited with discovering the rocket. The Chinese
used rockets they called “arrows of fire” against the attacking Mongols in 1232. The English
monk Roger Bacon developed an improved form of gunpowder in the mid-thirteenth century
that increased the range of rockets and improved their military potential.
For the next 700 years, rockets were used primarily for warfare with varying degrees of success.
The term “rocket” itself was first used in a topic written in 1577 by a German armorer named
Leonhart Fronsperger. Rockets were used in the Napoleonic Wars, the American Revolutionary
War, and in the American Civil War. There were some nonmilitary applications of rockets in
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