Nitrous oxide fuel blend

<h2 id="overview">Overview</h2>
Main article: <a href="/facts/Rocket_propellant/IyFhQEA2">Rocket propellant</a>
The propellant used in a rocket engine plays an important role in both engine design and in design of the <a href="/facts/Launch_vehicle/g1GCGFJB">launch vehicle</a> and related ground equipment to service the vehicle. Weight, <a href="/facts/Specific_energy/zVRhSxPh">energy density</a>, cost, toxicity, risk of explosions, and other problems make it important for engineers to design rockets with appropriate propellants. The major classes of rocket fuels are:

<table><tbody><tr><td>Fuel types<ul><li><a href="/facts/Liquid_rocket_propellants/s0KadvqW">Liquid rocket propellants</a></li><li><a href="/facts/Solid-fuel_rocket/RpgdYKIU">Solid propellants</a></li><li><a href="/facts/Hybrid_rocket/ya80c3xI">Hybrid rocket</a></li></ul></td><td></td><td>Designs using one or more fuels<ul><li><a href="/facts/Monopropellant_rocket/P6kj4xvT">Monopropellants</a></li><li><a href="/facts/Bipropellant/s0KadvqW">Bipropellants</a></li><li><a href="/facts/Tripropellant_rocket/B3u2zHTL">Tripropellants</a></li></ul></td></tr></tbody></table>

A common fuel in small maneuvering thrusters is <a href="/facts/Hydrazine/G7P5ITzU">hydrazine</a>. It is liquid at room temperature and, having a positive <a href="/facts/Enthalpy_of_formation/UFgGC7UQ">enthalpy of formation</a>, can be used as a monopropellant to greatly simplify system design. But it is also extremely toxic and has a relatively high freezing point of +1C. It is also unstable, an inherent property of any substance with a positive enthalpy of formation.
<a href="/facts/Nitrous_oxide/Jvys91lI">Nitrous oxide</a> can be used as an oxidizer with various fuels; it is popular mainly in <a href="/facts/Hybrid_rocket/ya80c3xI">hybrid rockets</a>. It is far less toxic than hydrazine and has a much lower boiling point, though it can be liquified at room temperature under pressure. Like hydrazine it has a positive enthalpy of formation that makes it both potentially unstable and a viable monopropellant. It can be decomposed with a catalyst to produce a hot mixture of nitrogen and oxygen.<a class="footnote-ref" id="fnref:1" href="#fn:1">1</a> When mixed with a fuel and stored before use, it becomes a mixed monopropellant.

<h2 id="history">History</h2>
German rocket scientists were experimenting with nitrous oxide fuel blends as early as 1937. Nitrous oxide fuel blends testing continued throughout <a href="/facts/World_War_II/2efV5L1U">World War II</a>. The promise of high performance, greater range and lighter feed systems drove experimentation with blends of nitrous oxide and ammonia, which resulted in numerous explosions and demolished motors.<a class="footnote-ref" id="fnref:2" href="#fn:2">2</a> The complexities involved in building propulsion systems that can safely handle nitrous oxide fuel blend monopropellants have been a deterrent to serious development.
Subsequent development of nitrous oxide fuel blends picked up again in the 2000s, and in 2011 an in-<a href="/facts/Outer_space/R3LRKyFs">space</a> <a href="/facts/Flight_test/uyrUsN4M">flight test</a> mission was planned. In the event, the flight test was cancelled. <a href="/facts/Innovative_Space_Propulsion_Systems/9rSz8Lhh">Innovative Space Propulsion Systems</a> had announced plans to test the NOFBX mono-propellant on the <a href="/facts/NASA/TIMCV0yV">NASA</a> portion of the <a href="/facts/International_Space_Station/VNPUBz9m">International Space Station</a> (ISS), with an initial tentative flight date no earlier than 2012.<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a> NASA formally approved the mission to the ISS on a 2013 launch slot in May 2012.<a class="footnote-ref" id="fnref:4" href="#fn:4">4</a> 
The mission had been slated to travel to the ISS in the unpressurized cargo compartment of a <a href="/facts/SpaceX_Dragon/oduVLMWr">SpaceX Dragon</a> spacecraft during one of the contracted NASA cargo re-supply missions in mid-2013. The "ISPS NOFBX Green Propellant Demonstration" will utilize a deep-throttling 100 pounds-force (440 N)-thrust-class engine burning NOFBX <a href="/facts/Rocket_engine/XT5gaFAb">rocket engine</a> that will be mounted to the outside the European <a href="/facts/Columbus_module/qYqbxpTR">Columbus module</a> on the ISS, and had been expected to remain on-orbit for approximately one year while undergoing a "series of in-space performance tests."<a class="footnote-ref" id="fnref:5" href="#fn:5">5</a>
NOFBX was a trademarked name for a proprietary nitrous oxide/<a href="/facts/Fuel/H8DIRL1j">fuel</a>/<a href="/facts/Emulsifier/YMSqSCuH">emulsifier</a> blended mono-propellant developed by Firestar Technologies.<a class="footnote-ref" id="fnref:6" href="#fn:6">6</a> The NOFBX patent claimed a mixture of nitrous oxide as the oxidizer with <a href="/facts/Ethane/BGCzc6yh">ethane</a>, <a href="/facts/Ethene/QMNBYLYn">ethene</a> or <a href="/facts/Acetylene/yaDh6cmJ">acetylene</a> as the fuel.[8] NOFBX has a higher <a href="/facts/Specific_impulse/JKGgw2I4">specific impulse</a> (Isp) and is less toxic than other monopropellants currently used in space applications, such as <a href="/facts/Hydrazine/G7P5ITzU">hydrazine</a>. Flight testing of NOFBX engines had been planned on the International Space Station,<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a> but, in the event, did not go forward.
NOFBX had previously been used to fuel a <a href="/facts/Reciprocating_engine/ItLAxmW3">reciprocating engine</a> to power high-altitude, long-endurance drone <a href="/facts/Aircraft/EhC4mBep">aircraft</a> under a <a href="/facts/Defense_Advanced_Research_Projects_Agency/Uf9sarhT">DARPA</a> contract.<a class="footnote-ref" id="fnref:8" href="#fn:8">8</a>
NOFBX was promoted by the company at the time as a "game changing" technology<a class="footnote-ref" id="fnref:9" href="#fn:9">9</a> with the several characteristics that underline why safer monopropellants were of interest in the industry:

<ul><li>constituents are widely available from chemical suppliers, inexpensive and safe to handle<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a></li>
<li>can be transported and handled without undue precautions or hazards<a class="footnote-ref" id="fnref:11" href="#fn:11">11</a></li>
<li>its end products (N2, CO, H2O, H2 and CO2)<a class="footnote-ref" id="fnref:12" href="#fn:12">12</a> are all substantially less toxic than traditional <a href="/facts/Storable_propellant/K88ymXRy">long-duration storable monopropellants</a> and produce no accumulated deposits or contamination;<a class="footnote-ref" id="fnref:13" href="#fn:13">13</a> whereas hydrazine emits ammonia<a class="footnote-ref" id="fnref:14" href="#fn:14">14</a></li>
<li>hydrazine has an <a href="/facts/Specific_impulse/JKGgw2I4">Isp</a> of about 230 s; NOFBX was reported to have an Isp of 300 s<a class="footnote-ref" id="fnref:15" href="#fn:15">15</a></li>
<li>has better <a href="/facts/Specific_energy/zVRhSxPh">energy density</a>, more than three times greater than hydrazine<a class="footnote-ref" id="fnref:16" href="#fn:16">16</a></li>
<li>is tolerant to a wide thermal range; storable at room temperature on the ground as well as in temperatures found in outer space<a class="footnote-ref" id="fnref:17" href="#fn:17">17</a></li>
<li>was projected to lower cost compared to existing propulsion systems of comparable performance<a class="footnote-ref" id="fnref:18" href="#fn:18">18</a></li>
<li>is a monopropellant, which significantly reduces the need for auxiliary hardware, saving cost, volume, and mass for launch systems</li>
<li>utilizes thrusters that run cooler, reducing thermal design challenges<a class="footnote-ref" id="fnref:19" href="#fn:19">19</a></li></ul>
<h2 id="safety-concerns">Safety concerns</h2>
A 2008 <a href="/facts/AIAA/fVbwtwh8">AIAA</a> paper on the decomposition of nitrous oxide has raised concerns about the safety risks of mixing hydrocarbons with nitrous oxide. By adding hydrocarbons, the <a href="/facts/Activation_energy/GqkgPvo0">energy barrier</a> to an explosive decomposition event is lowered significantly.<a class="footnote-ref" id="fnref:20" href="#fn:20">20</a>

<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Nitrous_oxide/Jvys91lI">Nitrous oxide</a></li></ul>

<ul><li>Sutton, George P.; Biblarz, Oscar (2001). Rocket Propulsion Elements (7th ed.). <a href="/facts/John_Wiley_%26_Sons/53g3LqJc">John Wiley & Sons</a>. p. 6. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-471-32642-9.</li></ul>
<h2 id="further-reading">Further reading</h2>
<ul><li>Doug Mohney (May 17, 2012). Brooke Neuman (ed.). <a href="http://satellite.tmcnet.com/topics/satellite/articles/2012/05/17/290846-green-propulsion-demo-passes-space-station-safety-review.htm">"Green Propulsion Demo Passes Space Station Safety Review"</a>. Satellite News. (talks about the (then upcoming) NASA safety review)</li>
<li>Schmidt, Eckart W. (2023). "Nitrous Oxide Monopropellants". Encyclopedia of Monopropellants. De Gruyter. pp. 1215–1436. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1515%2F9783110751390-009">10.1515/9783110751390-009</a>. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-11-075139-0.</li></ul>
<h2 id="external-links">External links</h2>
<ul><li><a href="http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=5&f=G&l=50&co1=AND&d=PG01&s1=Firestar&s2=Mungas&OS=Firestar+AND+Mungas&RS=Firestar+AND+Mungas">NOFBX patent application</a></li>
<li><a href="https://patents.google.com/patent/US20090133788A1">USPAT 20090133788 Nitrous oxide fuel blend monopropellants</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">Joiner, Stephen (May 1, 2011). "The Mojave Launch Lab". Air & Space Smithsonian. Retrieved March 18, 2011. (online publication date precedes print edition) <a href="http://www.airspacemag.com/space-exploration/The-Mojave-Launch-Lab.html" target="_blank">http://www.airspacemag.com/space-exploration/The-Mojave-Launch-Lab.html</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">Clark, John D. (1972). Ignition!: An Informal History of Liquid Rocket Propellants. Rutgers University Press. ISBN 978-0-8135-0725-5.[page needed] <a href="978-0-8135-0725-5" target="_blank">978-0-8135-0725-5</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">Messier, Doug (August 9, 2011). "A Non-Toxic Fuel From the Mojave Desert". Parabolic Arc. Archived from the original on October 7, 2011. Retrieved August 9, 2011. <a href="http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/" target="_blank">http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">Morring, Frank Jr. (May 21, 2012). "SpaceX To Deliver Green-Propulsion Testbed To ISS". Aviation Week and Space Technology. Retrieved May 24, 2012. <a href="http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_05_21_2012_p24-458579.xml" target="_blank">http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_05_21_2012_p24-458579.xml</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">"ISS-bound Propellant Demo Passes NASA Safety Review". Space News. May 29, 2012. p. 9. Retrieved June 26, 2012. <a href="http://www.spacenews.com/article/iss-bound-propellant-demo-passes-nasa-safety-review" target="_blank">http://www.spacenews.com/article/iss-bound-propellant-demo-passes-nasa-safety-review</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">"Firestar Technologies • Advanced Chemical Propulsion and Power Systems". Firestar-engineering.com. Retrieved December 30, 2013. <a href="http://www.firestar-engineering.com/NOFBX-MP.html" target="_blank">http://www.firestar-engineering.com/NOFBX-MP.html</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">"NOFBX Monopropulsion Overview" (PDF). Firestar Technologies. February 9, 2011. Archived from the original (PDF) on July 24, 2011. <a href="https://web.archive.org/web/20110724232730/http://www.aiaa.org/pdf/industry/presentations/Greg_Mungas.pdf" target="_blank">https://web.archive.org/web/20110724232730/http://www.aiaa.org/pdf/industry/presentations/Greg_Mungas.pdf</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">Joiner, Stephen (May 1, 2011). "The Mojave Launch Lab". Air & Space Smithsonian. Retrieved March 18, 2011. (online publication date precedes print edition) <a href="http://www.airspacemag.com/space-exploration/The-Mojave-Launch-Lab.html" target="_blank">http://www.airspacemag.com/space-exploration/The-Mojave-Launch-Lab.html</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">Messier, Doug (August 9, 2011). "A Non-Toxic Fuel From the Mojave Desert". Parabolic Arc. Archived from the original on October 7, 2011. Retrieved August 9, 2011. <a href="http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/" target="_blank">http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">Messier, Doug (August 9, 2011). "A Non-Toxic Fuel From the Mojave Desert". Parabolic Arc. Archived from the original on October 7, 2011. Retrieved August 9, 2011. <a href="http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/" target="_blank">http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
<li id="fn:11">Messier, Doug (August 9, 2011). "A Non-Toxic Fuel From the Mojave Desert". Parabolic Arc. Archived from the original on October 7, 2011. Retrieved August 9, 2011. <a href="http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/" target="_blank">http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></li>
<li id="fn:12">"NITROUS OXIDE FUEL BLEND MONOPROPELLANTS - Patent application". Faqs.org. Patent Docs. Retrieved December 30, 2013. <a href="http://www.faqs.org/patents/app/20090133788" target="_blank">http://www.faqs.org/patents/app/20090133788</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
<li id="fn:13">Messier, Doug (August 9, 2011). "A Non-Toxic Fuel From the Mojave Desert". Parabolic Arc. Archived from the original on October 7, 2011. Retrieved August 9, 2011. <a href="http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/" target="_blank">http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></li>
<li id="fn:14">"NITROUS OXIDE FUEL BLEND MONOPROPELLANTS - Patent application". Faqs.org. Patent Docs. Retrieved December 30, 2013. <a href="http://www.faqs.org/patents/app/20090133788" target="_blank">http://www.faqs.org/patents/app/20090133788</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></li>
<li id="fn:15">"NITROUS OXIDE FUEL BLEND MONOPROPELLANTS - Patent application". Faqs.org. Patent Docs. Retrieved December 30, 2013. <a href="http://www.faqs.org/patents/app/20090133788" target="_blank">http://www.faqs.org/patents/app/20090133788</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></li>
<li id="fn:16">"NITROUS OXIDE FUEL BLEND MONOPROPELLANTS - Patent application". Faqs.org. Patent Docs. Retrieved December 30, 2013. <a href="http://www.faqs.org/patents/app/20090133788" target="_blank">http://www.faqs.org/patents/app/20090133788</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></li>
<li id="fn:17">"NOFBX Monopropulsion Overview" (PDF). Firestar Technologies. February 9, 2011. Archived from the original (PDF) on July 24, 2011. <a href="https://web.archive.org/web/20110724232730/http://www.aiaa.org/pdf/industry/presentations/Greg_Mungas.pdf" target="_blank">https://web.archive.org/web/20110724232730/http://www.aiaa.org/pdf/industry/presentations/Greg_Mungas.pdf</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></li>
<li id="fn:18">Messier, Doug (August 9, 2011). "A Non-Toxic Fuel From the Mojave Desert". Parabolic Arc. Archived from the original on October 7, 2011. Retrieved August 9, 2011. <a href="http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/" target="_blank">http://www.parabolicarc.com/2011/08/09/a-non-toxic-fuel-from-the-mojave-desert/</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></li>
<li id="fn:19">"NOFBX Monopropulsion Overview" (PDF). Firestar Technologies. February 9, 2011. Archived from the original (PDF) on July 24, 2011. <a href="https://web.archive.org/web/20110724232730/http://www.aiaa.org/pdf/industry/presentations/Greg_Mungas.pdf" target="_blank">https://web.archive.org/web/20110724232730/http://www.aiaa.org/pdf/industry/presentations/Greg_Mungas.pdf</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></li>
<li id="fn:20">Karabeyoglu, A. (2008). "Modeling of N2O Decomposition Events". American Institute of Aeronautics and Astronautics. 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. Hartford, CT: Aerospace Research Central. doi:10.2514/6.2008-4933. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></li>
</ol>

Nitrous oxide fuel blend open-in-new

Nitrous oxide fuel blend