The FAQ!

This is a modified copy of the original FAQ. It is a really great one and please also visit their site for more infos. This version is more or less identical except that I modified it to fit our page design. In case somebody feels angry about me using it: drop me a note.

(start original FAQ)

This FAQ is not intended to be a complete course in rocketry. It covers some basics and has pointers to further information but from there, it's up to the reader. If there are any errors or if you know of something that really should be included, please email it the authors:,,

Some parts (it should be obvious which) are the authors' opinions. Feel free to disagree. While the authors tried to ensure the accuracy of the information in this FAQ, we make no warranty, express or implied, as to the validity or usefulness of anything that follows. You pays your money and you takes your chances.

1. Definitions
2. Rocketry Classes
3. Associations
4. Internet Resources
5. Books
6. Frequently Asked Questions
7 Suppliers
8. About aRocket
The following is a short list of terms, acronyms, and abbreviations that are commonly used on aRocket:
AN Ammonium Nitrate: Solid rocket oxidizer
AP Ammonium Perchlorate: Solid rocket oxidizer
BP Black Powder
Delta V Change in velocity
ELV Expendable Launch Vehicle
GLOW Gross Lift Off Weight: total rocket mass at the moment of lift off
GOX Gaseous Oxygen
GrEp Graphite Epoxy
H2O2 Hydrogen Peroxide: liquid oxidizer/monopropellant
HTPB Hydroxyl-terminated polybutadiene: Solid rocket fuel/binder
Hydrazine Liquid fuel
Hypergolic Fuel and oxidizer ignite spontaneously upon contact
Id Destiny Specific Impulse: product of specific gravity and specific impulse
Impulse Thrust Force * Time
Isp Specific Impulse: Thrust force per unit weight flow of propellant
LH2 Liquid Hydrogen
LOX Liquid Oxygen
Mass Ratio Final mass (after propellant burn) divided by initial mass
MMH Monomethylhydrazine: liquid fuel related to hydrazine
N2O Nitrous Oxide
Propellant Mass
Propellant mass divided by initial mass
RLV Reusable Launch Vehicle
RFNA Red Fuming Nitric Acid: liquid oxidizer; nitric acid with 5-20% nitrogen dioxide
RP1 Kerosene like fuel of higher purity for use in rocket engines
SSTO Single Stage To Orbit
TSTO Two Stage To Orbit
UDMH Unsymmetrical Dimethylhydrazine: liquid fuel related to hydrazine
Ullage Extra volume of gas above propellants in the tanks
Model Rocketry:

The kind of rockets everyone fooled around with as a kid. It uses only premanufactured, solid motors from class A to G. Restrictions: GLOW not to exceed 1500g; Each motor not to exceed 62.5g propellant and/or 160 NS impulse; Total propellant not to exceed 125g; No metal structural parts.

HPR - High Power Rocketry:

Scaled up model rocketry, using the same basic methods for construction, though metal parts can be used if necessary. It uses only premanufactured solid or hybrid motors from H to O. There are no weight restrictions, but each motor may not exceed 40,960 NS impulse and the total impulse may not exceed 81,920 NS.

Amateur Rocketry:

Anything that falls between HPR and professional rocketry. This includes liquid fueled engines, metal structures, building your own motors, and just about anything else you can think of. There are no formal definitions or requirements, other than the laws of physics and your government.

Experimental Rocketry:

Different people have used this to mean different things, but essentially it's the same as amateur rocketry.

Professional Rocketry:

Rocketry conducted for profit, usually by governments or large corporations.

European Model Rocketry Association

Probably the most interesting site for Europe.

NAR - National Association of Rocketry

The organization that regulates model rocketry in the United States.

TRA - Tripoli Rocketry Association

High power rocketry organization in the United States.

CAR - Canadian Association of Rocketry

The organization governing model and high power rocketry in Canada.

PRS - Pacific Rocket Society

One of the leading amateur rocketry organizations.

RRS - Reaction Research Society

The oldest amateur rocketry group in the United States, which operates a 40 acre test site north of Mojave, CA and Edwards AFB.

ERPS - Experimental Rocket Propulsion Society

Experimental Rocket Propulsion Society.

X-Prize Organization

They have put up a prize of $10 million US for the first group to fly a three man RLV to 100km twice in two weeks.

Books on Spacecraft Design and Spacecraft Systems
A listing of recommended reading on several spacecraft topics.
Blue Sky Rocket Science
This site focuses on solid propellants, with information on formulations, mixing, testing and more.
Rocketry Online
The most comprehensive model rocketry site on the net, it also has a few tidbits about amateur rocketry.
This web site, focusing on experimental and amateur rocketry.
DARTS Rocket Tracking System
A sophisticated computerized radar system for tracking rockets.
"How to Design, Build, and Test Small Liquid-Fuel Rocket Engines"
A great, but old, book on designing, building and testing small liquid fueled rocket engines.
This newsgroup is primarily for model rocketry and HPR so in-depth discussion of amateur rocketry wouldn't be appropriate, but occasionally something turns up that is of interest to amateurs.
The newsgroup dedicated to discussion of space hardware and technology. Occasionally, there are threads of interest to amateur rocketry.
Rec.Models.Rockets FAQ
Mostly information for model rocketry, but section 14 is about amateur rocketry.
The AUSROC Project
One of the most advanced (and certainly best documented on the net) amateur rockets ever built. Their detailed design report is very informative.
PROPEP Software
A DOS program that allows you to experiment with different combinations of fuel and oxidizer.
A graphical front end for PROPEP that makes it much easier to use.
Thomas Register
The folks who publish the mammoth set of industrial sourcebooks have put their database on the web. Once you register you can search for suppliers absolutely free.
Chemical Propulsion Information Agency
Run by Johns Hopkins University for the US Department of Defense. This web site has a searchable database of citations from 16,000 technical papers.

All of these books, and more, are listed in the Books section.

Rocket Propulsion Elements, 6th Edition
Sutton, G.P., 636 pages
1992, John Wiley & Sons, Inc.
ISBN 0-471-52938-9

The bible of amateur rocketry. It covers all the theory of rocket propulsion, including liquid, solid and hybrid, with formulas. Not for the math-shy, but then what did you expect? Pricey but essential reading if you're serious about building rockets.

Modern Engineering for Design of Liquid-Propellant Rocket Engines
Dieter Huzel and David Huang, 431 pages
1992, AIAA, Inc.
ISBN 1-56347-013-6

Written by folks who know rocket engines, this book has just about everything you need to know about liquid rockets. It covers engine design, pressure fed & turbopump propellant systems, engine control & monitoring, propellant tanks, interconnecting components and system integration. It has diagrams galore and lots real-world examples. Highly recommended.

Orbital Mechanics
John Prussing and Bruce Conway, 194 pages
1993, Oxford
ISBN 0-19-507834-9

A solid introduction to the mathematics necessary to calculate orbits.

Composite Basics, 4th Edition
Andrew Marshall, 150 pages

It covers the different fabrics and resins available, construction techniques, analysis and testing. Available from Fibre Glast.

Cryogenic Engineering
Russel B. Scott, 368 pages
1988 Met-Chem Research
ISBN 0-931913-10-1

It covers the basic science of cryogenics, as well as practical handling and engineering issues. It is a bit dated, however.

Almost any good bookstore will be able to order you any technical book that's still in print. However, you will likely pay full price. The following are some Internet sources that offer various discounts.
Amazon.Com Books
"World's Largest Bookstore" They offer an amazing selection of all kinds of books, but the discounts are generally only enough to pay for shipping.
OPAMP Technical Books
A good source for rocketry and engineering books.
The largest (physical) bookstore in North America, they have a good selection of new and used technical books. The used ones are often less than half the cost of new.
DAB - Discount Astronautical Bookstore
Microcosm's parent company, (the people working on low cost liquid engines) it usually offers the best prices on the books it carries. They also offer discounts for purchasing multiple books.
How to Design, Build, and Test Small Liquid-Fuel Rocket Engines

This is an HTML book that has been scanned from the original 1967 hardcopy, now out of print. It's a good introduction to the nuts and bolts of rocket engine design and construction, but it is a bit limited in that it only deals with building a test stand motor, not flight-quality hardware. It's also a bit dated (the list of suppliers is reportedly of little use,) but you can't beat the price.

Propulsion Research Laboratories
3439 Hamlin Ave
Simi Valley, CA 93063

They publish a number of interesting reports, plans and video tapes about amateur rockets.

Systeme Solaire
4414 Notre Dame
Chomedey, Laval
Quebec, Canada H7W-1T6
Fax: (514) 621-1062

They sell plans for a gasoline (and peroxide?) rocket, though customer service is reported to be somewhat lacking.

Gas Dynamics Lab
P.O. Box 465
Watkinsville, GA 30677

James Lanier's home page promoting his composite motor book "Rocket Motor Design."

Journal of Pyrotechnics
1775 Blair Road
Whitewater, CO 81527
Phone: (970) 245-0692

Semi-annual publication on pyrotechnics with some info on solid rockets.

1) Which is best for amateur rocketry: solid, liquid, or hybrid propulsion?

The question gets a lot of debate. As with anything else, it depends on a number of factors, and there's no definite answer. Factors that should be considered include: your personal background and knowledge; size of rocket; impulse required; specific impulse desired; thrust; monies available; reliability factor; materials and equipment available; legal aspects; etc.

Generally, very small rockets (up to several kg or tens of kg) are easiest to build as solids or hybrids, and a lot of the technology is already available. Liquids provide the highest specific impulse and are most economical in larger sizes but are more complex. Hybrids tend to bridge the gap between liquids and solids, providing better impulse in mid-size than solids and being simpler than liquids.

2) "How do I build rocket motors?"

There is no easy answer to this. You need to buy the books, join an amateur group, do the research, and understand what you're doing. Blindly following a recipe you found is asking for the sudden removal of your extremities.

3) "Where can I get LOX?"

Check with welding supply companies in your area or with the local outlets of Air Liquide and Praxair, listed in the Suppliers section. If all else fails, medical supply companies sell it for respirators, though you'll pay through the nose (pun intended) and they may have restrictions. Price varies widely, so shop around.

4) "Where can I get transducers, DAQ boards, valves, fiberglass, etc?"

Check out the suppliers section below and the yellow pages in major cities. If you can't find what you want, try the Thomas Register at a university library or online (see the Internet Resources section above.)

5) "Putting a rocket into orbit looks easy. How come no amateur has done it yet?"

Short answer: Because it ain't easy, not even close.

Long answer: There are several inter-related reasons: Scalability, Materials, Methods, Development, Cost, and Time.

SCALABILITY: Some rocket components are impractical on a small scale, for instance turbopumps and hydraulic systems. Rockets also suffer from the effects of the cube/square law as they get smaller, particularly tanks.

MATERIALS: There is a sliding scale of price and performance: steel,aluminum, alloys, fiberglass, graphite, and someday, buckytube. Generally, the higher the strength to weight ratio, the higher the price. Graphite fibre is *expensive.* And if you go cheap, performance suffers.

METHODS: Advanced manufacturing techniques are likely to be out of reach of the average amateur. Not many of us have a filament winding machine in the garage. And the best way to implement regenerative cooling is to machine the coolant passages in the walls of the engine, fill them with wax,electro-deposit a "roof" and then melt the wax out. That's beyond the capacity of any amateur I know. If you contract for those kinds of jobs, you drive the price way up, and if you use simpler methods, performance suffers.

DEVELOPMENT: You can't buy a kit, slap the pieces together, and put a satellite in orbit (not yet anyway.) This is real R&D: you're going to have to build a prototype, test it, build another, test it, build another and soon. For each of three stages. And things go wrong: valves stick, plumbing leaks, rockets blow up. And then there's the support equipment; you're going to have to build a test stand, data acquisition system, fuel loader, launch pad, tracking system and more. All of this takes time and, yes, money.

COST: The big one. All the other factors contribute to the cost, and it adds up in a hurry. How much would it cost to do a "Sputnik?" More than $25,000. Some groups have spent that much already, and are still nowhere near orbit. $100,000 is probably in the ballpark. (Note: that's the cost of the entire program, not just the flight.)

TIME: The key word here is "amateur." These people are not paid to build rockets. They have regular jobs and only do it in their spare time. This doubles or triples development time.

Short answer #2: If that still doesn't convince you, try it yourself.

6) "What materials should I use for my rocket motor?"

In Appendix C of Huzel & Huang there is a brief description of the materials being used in modern rocket engines.

7) "Why don't we start a newsgroup for amateur rockets instead of a mailing list?"

Mailing lists have a very strong self-selection factor; you have to want to join up. Moving to a newsgroup would bring a higher profile, but it would also bring the spammers, flamers and the truly clueless. The average IQ in USENET has been plunging in recent years, with no sign of bottom. Most of us do not want to be pestered by endless repetitions of Question #1.

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