Handling Considerations of Nitrous Oxide in Hybrid Rocket Motor Testing

              American Institute of Aeronautics and Astronautics
Copyright © 2008 by SpaceDev Inc. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.
1
Handling Considerations of Nitrous Oxide in Hybrid Rocket
Motor Testing
Zachary Thicksten1, Frank Macklin2, and John Campbell3
SpaceDev Inc., Poway, CA, 92064, USA
Nitrous Oxide has many beneficial properties that make it a good choice for use in hybrid rocket motors.
The large quantities and potentially high pressures used in rocket motors present unique hazards that are not
generally found in the standard industrial and medical uses of nitrous oxide. Through years of hands on use,
and research into the properties of nitrous oxide, SpaceDev has created a set of guidelines on how to design,
clean, and inspect systems using nitrous oxide. This paper presents the nitrous oxide handling precautions
and procedures employed by SpaceDev in the testing of hybrid rocket motors.
Nomenclature
AMROC = American Rocket Corporation
BAA = Broad Agency Announcement
HTPB = Hydroxyl-Terminated Polybutadiene
LOX = Liquid Oxygen
N2O = Nitrous Oxide
PMMA = Polymethyl Methacrylate
I. Introduction
ITROUS Oxide has recently seen a lot of interest as an oxidizer for hybrid rockets. Nitrous oxide has many
properties which make it a good choice for a variety of different mission applications. It is non-toxic, long
term storable, has good density, a high vapor pressure, and has good overall performance. However, nitrous oxide
is exothermic, and is an oxidizer. As with all oxidizers and exothermic materials, proper care needs to be taken
when handling nitrous oxide.
Engineers using nitrous oxide for rocket propulsion systems need to recognize that it does have the potential to
rapidly decompose when exposed to ignition sources or, if contaminated with fuels, burn. Both the rapid
decomposition and / or burning can lead to explosions from pressure vessel failures. A decomposition reaction of
nitrous oxide can increase the pressure in a tank or line by over an order of magnitude in a fraction of a second.
However, it is possible to avoid nitrous oxide decomposition through the use of proper storage and handling
techniques. It is essential to isolate nitrous oxide systems from possible ignition sources and to keep contaminates
out of the system. When proper procedures are followed nitrous oxide is one of the safer oxidizers used today in
rocket motors.
This paper highlights the training, handling and safety procedures employed by SpaceDev in the testing and
operation of hybrid rocket motors. This paper is intended only to highlight how SpaceDev handles nitrous oxide and
is not intended to be used as a comprehensive guide on the design of nitrous oxide systems or nitrous oxide safety.
While SpaceDev has done its best to verify that all the information contained in this paper is factually correct,
SpaceDev assumes no liability for errors contained within this paper.
1 Propulsion Engineer, SpaceDev Inc., 13855 Stowe Dr. Poway CA 92064, AIAA Member.
2 Manager of Manufacturing and Testing, SpaceDev Inc., 13855 Stowe Dr. Poway CA 92064, AIAA Member.
3 V.P. of Engineering, SpaceDev Inc., 13855 Stowe Dr. Poway CA 92064, AIAA Member.
N
44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit
21 - 23 July 2008, Hartford, CT
AIAA 2008-4830
Copyright © 2008 by SpaceDev Inc. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.