Text Only Site
+ Non-Flash Version
The Beginner's Guide to Rockets (BGR) was created
as a Web-based "textbook." The creation of the BGR is a research project
to explore the use of the personal computer and the Internet to present educational
materials to students, teachers, and lifelong learners in a more interactive
way than a printed, bound textbook.
As a general rule, the Web consists of many individual pages that are
connected, or related, to one another through hyperlinks. The Web is,
therefore, much less structured than a bound book, in which one page follows
another in a definite, numbered sequence. We have intentionally organized the
BGR to mirror this unstructured approach. Users can navigate the pages
of the BGR through hyperlinks based on their own interest and inquiry.
For those who prefer more structure to the information available at the BGR,
we have organized an alternative to the unstructured approach--a number of guided
tours through the site. Each tour is organized around a single topic, and
users move from page to page through the tour by using special buttons at the
bottom of each page.
Click to move back to the previous page.
Click to move to the next page.
Click to return to this page at the end of each tour.
(Some pages will be "crossed" by more than one tour, so it is important
to remember which tour you are on. If you click on a hyperlink you will leave
the tour; you can rejoin the tour by using the browser's "Back" command.
If you wish to abort a tour and return here, just click on the "Guided Tours" label
located above the buttons.
All of the tours begin and end on this page unless otherwise noted.
Descriptions of each tour are given below--just click on the
name of the tour to start you on your way.
- Our Neighbors in Space In the coming years we
will be visiting our nearest celestial neighbors. Here is some information
comparing the Earth, Moon, and Mars.
- Newton's Laws of Motion The motion of rocket
can be accurately described by the classical Laws of Motion developed by Sir
Isaac Newton in the late 1600's.
- Forces, Torques, and Motion As an object
moves through space it translates and rotates. The translations are in direct
response to forces on the object. The rotations are in response to torques
on the object.
- Thermodynamics Thermodynamics is the study
of the effects of work, heat and energy on a system. There are three laws of
thermodynamics based on large scale observations.
- Combustion Rockets are powered
by rocket engines which produce thrust by burning a fuel. Combustion is the
chemical process which combines fuel, oxygen, and a source of heat to
produce heat and exhaust products.
- Functions A function is a mathematical process
that uniquely relates the value of one variable to the value of one or more
- Scalars Scalar quantities have only
a magnitude. Engineers often compare scalar quantities by division to
- Vectors Vector quantities have two
characteristics; magnitude and direction. When performing any mathematical
operation, one must consider both magnitude and direction.
- Trigonometry Trigonometry is the study of
Gas Dynamics and Statics
- Basic Fluid Dynamics Equations
Thrust is generated in a rocket engine by moving hot gases or fluids.
The motion of any fluid
can be described by the conservation of mass, momentum, and energy.
- Compressible Aerodynamics
Additional effects are present when a fluid travels at
speeds near or faster than the speed of sound for the gas.
Shock waves or expansions may be present in the flow field.
- Speed of Sound Small disturbances in a
gas are transmitted at the speed of sound. The speed of sound depends on the temperature of the gas.
The Mach number is the ratio of an object's speed to the speed of sound.
- Isentropic Flow The results of some of the fluid
problems can be reversed and returned to their original conditions. These flows
are called isentropic (constant entropy) flows.
- Shock Waves Shock waves are generated
by a rocket as it flies supersonically. Shock waves are very small regions
where the flow variables change by a large amount.
- Viscous Aerodynamics
The viscosity of a gas produces friction forces on a fluid moving past
a surface. Boundary layers and flow separation are sources of drag on the
- Gas Statics
The properties of a gas
are related to one another. You can learn about the properties of a gas by
considering a static volume of gas.
- Standard Atmosphere Model The atmosphere
is a thin layer of gas that separates the surface of the planet from outer
space. The properties of the gas change with altitude through the atmosphere.
- Forces on a Rocket There are four main
forces which act on a rocket in flight; weight, thrust, drag, and lift. Lift
and drag are actually two components of a single aerodynamic force.
- Rocket Weight Weight is a major design
consideration for all rockets. Equations have been developed to compute the
rocket's weight and center of gravity during design.
- Rocket Thrust Unlike airplanes, rockets
use thrust to overcome weight. Equations have been developed to compute
the thrust produced by a rocket engine.
- Rocket Aerodynamics Aerodynamics play a major
role in the flight of model rockets, and a lesser role for full scale rockets.
Equations have been developed to compute the aerodynamic force on a rocket.
- Types of Rockets There are many different
types of rockets. This tour looks at some examples and compares model rockets to
full scale rockets.
- Compressed Air The first rocket that
many students study is the compressed air, or stomp, rocket. This rocket has
constant weight and no thrust during the flight.
- Water Rocket The water rocket is similar
to the compressed air rocket, but uses pressurized water as a propellant. The rocket
weight and thrust change during launch, then the rocket coasts during flight.
- Model Rockets Model rockets use small
solid rocket engines to provide thrust at launch, then coast to a high altitude, where
a parachute is deployed for recovery.
- Full Scale Rockets Full scale rockets use either
liquid or solid rocket engines to provide thrust at launch. These rockets use sophisticated
guidance systems to place spacecraft in orbit.
- Rocket Systems A rocket is composed of many
parts. The parts are grouped into systems which perform a function. This tour examines
the four major systems of a full scale rocket.
- Payload System Moving a payload system to
some altitude above the surface of the planet is the ultimate objective of rocketry.
The payload may include people, satellites, warheads, or scientific instruments.
- Structural System The structural system
transmits forces through the frame of the rocket. It must be very strong but
light in weight,
- Guidance System The guidance system
has two main functions; to maintain the stability of the rocket in flight,
and to control the flight path of the rocket.
- Propulsion System The propulsion system
generates thrust which is used to overcome the weight of the rocket.
- Rocket Flight The motion of a rocket through
the air and through space is a combination of translation of the center of
gravity and rotation about the center of gravity. This tour examines the basics
of rocket motion.
- Rocket Translation The motion of the
the center of gravity from one location to another is called translation.
Equations have been developed to describe the translation of a rocket through space.
- Rocket Rotation The motion of the
rocket about its center of gravity is called rotation.
Equations have been developed to describe the rotation of a rocket during flight.
- Flight Equations The motion of a
rocket can be described by mathematical equations derived from Newton's second
law of motion. The exact form of the equations depend on the nature of the forces
acting on the rocket.
- Maximum Altitude When firing model rockets,
we often want to determine how high the rocket flew. Here are two techniques to
experimentally determine how high a rocket flies and a calculator
to predict how high a model rocket will fly.
Simulators and Calculators
- RocketModeler II - Model Rocket Simulator RocketModeler is an
interactive computer program that lets you design and flight test a
variety of rockets.
- Rocket Thrust Simulator Thrust Simulator is an
interactive computer program that lets you design and analyze a rocket nozzle.
- Atmospheric Effects Simulator Atmospheric Effects Simulator
calculates the change in thermodynamic state variables with change in altitude for
both the Earth and Mars and its effect on aerodynamic variables.
- Shock Simulator Shock Simulator
calculates the change in flow variables across a single oblique or normal shock.
- Multiple Shock Simulator Multiple Shock Simulator
calculates the change in flow variables through crossed shocks, reflecting shocks, and
- Animated Gas Lab Animated Gas Lab
is a series of computer animations which demonstrate all of the possible combinations
of the ideal gas law and equation of state.
- Ballistic Flight Calculator This program calculates
the maximum height of a launched ballistic shell, or a shell with drag, and the time from
launch when the maximum height is reached.
- Terminal Velocity Calculator This program calculates
the terminal velocity of a falling object.
- Circular Orbit Calculator This program calculates
the altitude and velocity of an object in a circular orbit about the Earth, Moon or Mars.
- Rocket Altitude Calculator This program calculates
the model rocket altitude using trigonometry applied to experimental measurements.
- Mach and Speed of Sound Calculator This program calculates
the speed of sound as a function of temperature and the Mach number as function of
object speed and speed of sound.
- Isentropic Flow Calculator This program calculates
all of the flow variable ratios present in an isentropic flow.
Exploration Systems Mission Directorate Home