Nitrous oxide fuel blend

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Nitrous oxide fuel blend propellants are a class of liquid rocket propellants that were intended in the early 2010s to be able to replace hydrazine as the standard storable rocket propellent in some applications.

Contents

In nitrous-oxide fuel blends, the fuel and oxidizer are blended and stored; this is sometimes referred to as a mixed monopropellant. Upon use, the propellant is heated or passed over a catalyst bed and the nitrous oxide decomposes into oxygen-rich gasses. Combustion then ensues. Special care is needed in the chemical formulation and engine design to prevent detonating the stored fuel.

Overview

The propellant used in a rocket engine plays an important role in both engine design and in design of the launch vehicle and related ground equipment to service the vehicle. Weight, energy density, 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:

A common fuel in small maneuvering thrusters is hydrazine. It is liquid at room temperature and, having a positive enthalpy of formation, 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.

Nitrous oxide can be used as an oxidizer with various fuels; it is popular mainly in hybrid rockets. 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. [1] When mixed with a fuel and stored before use, it becomes a mixed monopropellant.[ citation needed ]

History

German rocket scientists were experimenting with nitrous oxide fuel blends as early as 1937. Nitrous oxide fuel blends testing continued throughout World War II. 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. [2] 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-space flight test mission was planned. In the event, the flight test was cancelled. Innovative Space Propulsion Systems had announced plans to test the NOFBX mono-propellant on the NASA portion of the International Space Station (ISS), with an initial tentative flight date no earlier than 2012. [3] NASA formally approved the mission to the ISS on a 2013 launch slot in May 2012. [4] The mission had been slated to travel to the ISS in the unpressurized cargo compartment of a SpaceX Dragon 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 rocket engine that will be mounted to the outside the European Columbus module on the ISS, and had been expected to remain on-orbit for approximately one year while undergoing a "series of in-space performance tests." [5]

NOFBX was a trademarked name for a proprietary nitrous oxide/fuel/emulsifier blended mono-propellant developed by Firestar Technologies. [6] The NOFBX patent claimed a mixture of nitrous oxide as the oxidizer with ethane, ethene or acetylene as the fuel.[8] NOFBX has a higher specific impulse (Isp) and is less toxic than other monopropellants currently used in space applications, such as hydrazine. Flight testing of NOFBX engines had been planned on the International Space Station, [7] but, in the event, did not go forward.

NOFBX had previously been used to fuel a reciprocating engine to power high-altitude, long-endurance drone aircraft under a DARPA contract. [1] NOFBX was promoted by the company at the time as a "game changing" technology [3] with the several characteristics that underline why safer monopropellants were of interest in the industry:

Safety concerns

A 2008 AIAA paper on the decomposition of nitrous oxide has raised concerns about the safety risks of mixing hydrocarbons with nitrous oxide. By adding hydrocarbons, the energy barrier to an explosive decomposition event is lowered significantly. [9]

See also

Related Research Articles

<span class="mw-page-title-main">Hybrid-propellant rocket</span> Rocket engine that uses both liquid / gaseous and solid fuel

A hybrid-propellant rocket is a rocket with a rocket motor that uses rocket propellants in two different phases: one solid and the other either gas or liquid. The hybrid rocket concept can be traced back to the early 1930s.

A monopropellant rocket is a rocket that uses a single chemical as its propellant. Monopropellant rockets are commonly used as small attitude and trajectory control rockets in satellites, rocket upper stages, manned spacecraft, and spaceplanes.

<span class="mw-page-title-main">Hydrazine</span> Colorless flammable liquid with an ammonia-like odor

Hydrazine is an inorganic compound with the chemical formula N2H4. It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydrazine hydrate.

<span class="mw-page-title-main">Hypergolic propellant</span> Type of rocket engine fuel

A hypergolic propellant is a rocket propellant combination used in a rocket engine, whose components spontaneously ignite when they come into contact with each other.

Monopropellants are propellants consisting of chemicals that release energy through exothermic chemical decomposition. The molecular bond energy of the monopropellant is released usually through use of a catalyst. This can be contrasted with bipropellants that release energy through the chemical reaction between an oxidizer and a fuel. While stable under defined storage conditions, monopropellants decompose very rapidly under certain other conditions to produce a large volume of its own energetic (hot) gases for the performance of mechanical work. Although solid deflagrants such as nitrocellulose, the most commonly used propellant in firearms, could be thought of as monopropellants, the term is usually reserved for liquids in engineering literature.

A propellant is a mass that is expelled or expanded in such a way as to create a thrust or another motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the engine that expels the propellant is called a reaction engine. Although technically a propellant is the reaction mass used to create thrust, the term "propellant" is often used to describe a substance which contains both the reaction mass and the fuel that holds the energy used to accelerate the reaction mass. For example, the term "propellant" is often used in chemical rocket design to describe a combined fuel/propellant, although the propellants should not be confused with the fuel that is used by an engine to produce the energy that expels the propellant. Even though the byproducts of substances used as fuel are also often used as a reaction mass to create the thrust, such as with a chemical rocket engine, propellant and fuel are two distinct concepts.

Monomethylhydrazine is a highly toxic, volatile hydrazine derivative with the chemical formula CH6N2. It is used as a rocket propellant in bipropellant rocket engines because it is hypergolic with various oxidizers such as nitrogen tetroxide and nitric acid. As a propellant, it is described in specification MIL-PRF-27404.

<span class="mw-page-title-main">RP-1</span> Highly refined form of kerosene used as rocket fuel

RP-1 (alternatively, Rocket Propellant-1 or Refined Petroleum-1) is a highly refined form of kerosene outwardly similar to jet fuel, used as rocket fuel. RP-1 provides a lower specific impulse than liquid hydrogen (H2), but is cheaper, is stable at room temperature, and presents a lower explosion hazard. RP-1 is far denser than H2, giving it a higher energy density (though its specific energy is lower). RP-1 also has a fraction of the toxicity and carcinogenic hazards of hydrazine, another room-temperature liquid fuel.

A solar thermal rocket is a theoretical spacecraft propulsion system that would make use of solar power to directly heat reaction mass, and therefore would not require an electrical generator, like most other forms of solar-powered propulsion do. The rocket would only have to carry the means of capturing solar energy, such as concentrators and mirrors. The heated propellant would be fed through a conventional rocket nozzle to produce thrust. Its engine thrust would be directly related to the surface area of the solar collector and to the local intensity of the solar radiation.

<span class="mw-page-title-main">Liquid-propellant rocket</span> Rocket engine that uses liquid fuels and oxidizers

A liquid-propellant rocket or liquid rocket utilizes a rocket engine burning liquid propellants. (Alternate approaches use gaseous or solid propellants.) Liquids are desirable propellants because they have reasonably high density and their combustion products have high specific impulse (Isp). This allows the volume of the propellant tanks to be relatively low.

Aerozine 50 is a 50:50 mix by weight of hydrazine and unsymmetrical dimethylhydrazine (UDMH), developed in the late 1950s by Aerojet General Corporation as a storable, high-energy, hypergolic fuel for the Titan II ICBM rocket engines. Aerozine continues in wide use as a rocket fuel, typically with dinitrogen tetroxide as the oxidizer, with which it is hypergolic. Aerozine 50 is more stable than hydrazine alone, and has a higher density and boiling point than UDMH alone.

The highest specific impulse chemical rockets use liquid propellants. They can consist of a single chemical or a mix of two chemicals, called bipropellants. Bipropellants can further be divided into two categories; hypergolic propellants, which ignite when the fuel and oxidizer make contact, and non-hypergolic propellants which require an ignition source.

<span class="mw-page-title-main">Hydroxylammonium nitrate</span> Chemical compound

Hydroxylammonium nitrate or hydroxylamine nitrate (HAN) is an inorganic compound with the chemical formula [NH3OH]+[NO3]−. It is a salt derived from hydroxylamine and nitric acid. In its pure form, it is a colourless hygroscopic solid. It has potential to be used as a rocket propellant either as a solution in monopropellants or bipropellants. Hydroxylammonium nitrate (HAN)-based propellants are a viable and effective solution for future green propellant-based missions, as it offers 50% higher performance for a given propellant tank compared to commercially used hydrazine.

<span class="mw-page-title-main">Ammonium dinitramide</span> Chemical compound

Ammonium dinitramide (ADN) is an inorganic compound with the chemical formula [NH4][N(NO2)2]. It is the ammonium salt of dinitraminic acid HN(NO2)2. It consists of ammonium cations [NH4]+ and dinitramide anions −N(NO2)2. ADN decomposes under heat to leave only nitrogen, oxygen, and water.

ECAPS AB is a Swedish spacecraft propulsion company, established in 2000 as a joint venture between the Swedish Space Corporation (SSC) and Volvo Aero with the goal of developing and commercializing in-space thruster technology using a low toxicity Ammonium dinitramide (ADN) based liquid monopropellant called LMP-103S.

<span class="mw-page-title-main">Pintle injector</span> Propellant injection device for a rocket engine.

The pintle injector is a type of propellant injector for a bipropellant rocket engine. Like any other injector, its purpose is to ensure appropriate flow rate and intermixing of the propellants as they are forcibly injected under high pressure into the combustion chamber, so that an efficient and controlled combustion process can happen.

<span class="mw-page-title-main">Orbital Maneuvering System</span> Hypergolic orbital maneuvering engines used on NASAs Space Shuttle

The Orbital Maneuvering System (OMS) is a system of hypergolic liquid-propellant rocket engines used on the Space Shuttle and the Orion MPCV. Designed and manufactured in the United States by Aerojet, the system allowed the orbiter to perform various orbital maneuvers according to requirements of each mission profile: orbital injection after main engine cutoff, orbital corrections during flight, and the final deorbit burn for reentry. From STS-90 onwards the OMS were typically ignited part-way into the Shuttle's ascent for a few minutes to aid acceleration to orbital insertion. Notable exceptions were particularly high-altitude missions such as those supporting the Hubble Space Telescope (STS-31) or those with unusually heavy payloads such as Chandra (STS-93). An OMS dump burn also occurred on STS-51-F, as part of the Abort to Orbit procedure.

<span class="mw-page-title-main">Rocket propellant</span> Chemical or mixture used as fuel for a rocket engine

Rocket propellant is the reaction mass of a rocket. This reaction mass is ejected at the highest achievable velocity from a rocket engine to produce thrust. The energy required can either come from the propellants themselves, as with a chemical rocket, or from an external source, as with ion engines.

<span class="mw-page-title-main">Green Propellant Infusion Mission</span> NASA satellite testing a new rocket fuel

The Green Propellant Infusion Mission (GPIM) was a NASA technology demonstrator project that tested a less toxic and higher performance/efficiency chemical propellant for next-generation launch vehicles and CubeSat spacecraft. When compared to the present high-thrust and high-performance industry standard for orbital maneuvering systems, which for decades, have exclusively been reliant upon toxic hydrazine based propellant formulations, the "greener" hydroxylammonium nitrate (HAN) monopropellant offers many advantages for future satellites, including longer mission durations, additional maneuverability, increased payload space and simplified launch processing. The GPIM was managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, and was part of NASA's Technology Demonstration Mission Program within the Space Technology Mission Directorate.

NASA's Pathfinder Technology Demonstrator (PTD) Project is a series of tech demonstrations of technologies aboard a series of nanosatellites known as CubeSats, providing significant enhancements to the performance of these versatile spacecraft. Each of the five planned PTD missions consist of a 6-unit (6U) CubeSat with expandable solar arrays.

References

  1. 1 2 Joiner, Stephen (May 1, 2011). "The Mojave Launch Lab". Air & Space Smithsonian. Retrieved March 18, 2011.(online publication date precedes print edition)
  2. ↑ Clark, John D. (1972). Ignition!: An Informal History of Liquid Rocket Propellants. Rutgers University Press. ISBN   978-0-8135-0725-5.[ page needed ]
  3. 1 2 3 4 5 6 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.
  4. ↑ Morring, Frank Jr. (May 21, 2012). "SpaceX To Deliver Green-Propulsion Testbed To ISS" . Aviation Week and Space Technology. Retrieved May 24, 2012.
  5. ↑ "ISS-bound Propellant Demo Passes NASA Safety Review". Space News. May 29, 2012. p. 9. Retrieved June 26, 2012.
  6. ↑ "Firestar Technologies • Advanced Chemical Propulsion and Power Systems". Firestar-engineering.com. Retrieved December 30, 2013.
  7. 1 2 3 "NOFBX Monopropulsion Overview" (PDF). Firestar Technologies. February 9, 2011. Archived from the original (PDF) on July 24, 2011.
  8. 1 2 3 4 "NITROUS OXIDE FUEL BLEND MONOPROPELLANTS - Patent application". Faqs.org. Patent Docs. Retrieved December 30, 2013.
  9. ↑ 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.

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