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.[1] 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.
The compound is a salt with separated hydroxyammonium and nitrate ions.[2] Hydroxylammonium nitrate is unstable because it contains both a reducing agent (hydroxylammonium cation) and an oxidizer (nitrate),[3] the situation being analogous to ammonium nitrate. It is usually handled as an aqueous solution. The solution is corrosive and toxic, and may be carcinogenic. Solid HAN is unstable, especially in the presence of trace amounts of iron(III).
HAN has applications as a component of rocket propellant, in both solid and liquid form. HAN and ammonium dinitramide (ADN), another energetic ionic compound, were investigated as less-toxic replacements for toxic hydrazine for monopropellant rockets where only a catalyst is needed to cause decomposition.[4] HAN and ADN will work as monopropellants in water solution, as well as when dissolved with fuel liquids such as methanol.
HAN also enabled the development of solid propellants that could be controlled electrically and switched on and off.[6] Developed by DSSP for special effects[7] and microthrusters, these were the first HAN-based propellants in space; and aboard the Naval Research Laboratory SpinSat, launched in 2014.[8][9]
It was used in a fuel/oxidizer blend known as "AF-M315E"[1] in the high thrust engines of the Green Propellant Infusion Mission,[10][11][12] which was initially expected to be launched in 2015, and eventually launched and deployed on 25 June 2019.[13] The specific impulse of AF-M315E is 257 s.[1]
The aqueous solution of HAN can be added with fuel components such as methanol, glycine, TEAN (triethanolammonium nitrate), and amines to form high performance monopropellants for space propulsion systems.[14]
Donald G. Harlow et al. (1998). "Technical Report on Hydroxlyamine Nitrate". U.S. Department of Energy. DOE/EH-0555
Gösta Bengtsson et al. (2002) "The kinetics and mechanism of oxidation of hydroxylamine by iron(III)". J. Chem. Soc., Dalton Trans., 2002, 2548–2552. doi:10.1039/B201602H
^ abcSpores, Ronald A.; Masse, Robert; Kimbrel, Scott; McLean, Chris (15–17 July 2013). "GPIM AF-M315E Propulsion System"(PDF). San Jose, California, USA: 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. Archived(PDF) from the original on 2014-02-28.
^Rheingold, A. L.; Cronin, J. T.; Brill, T. B.; Ross, F. K. (March 1987). "Structure of hydroxylammonium nitrate (HAN) and the deuterium homolog". Acta Crystallographica Section C. 43 (3): 402–404. doi:10.1107/S0108270187095593.
^Sawka, Wayne N.; McPherson, Michael (2013-07-12), "Electrical Solid Propellants: A Safe, Micro to Macro Propulsion Technology", 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Joint Propulsion Conferences, American Institute of Aeronautics and Astronautics, doi:10.2514/6.2013-4168, ISBN978-1-62410-222-6
^Nicholas, Andrew; Finne, Ted; Gaylsh, Ivan; Mai, Anthony; Yen, Jim (September 2013). "SpinSat Mission Overview"(PDF). Archived(PDF) from the original on June 19, 2019.
^Wucherer, E.; Christofferson, Stacy; Reed, Brian (2000). Assessment of high performance HAN-monopropellants. 36th AIAA/ASME/SAE/ASEE Joint Propulsion Conference. doi:10.2514/6.2000-3872.
^航天科技六院801所HAN 基无毒推进发动机研制攻关记 [HAN-based non-toxic propulsion engine research and development of 801 Institute of the Sixth Academy of Space Science and Technology] (in Chinese (China)). China Aerospace Science and Technology Corporation. 24 May 2019. Retrieved 14 May 2020.
^小型実証衛星1号機 RAPIS-1 グリーンプロペラント推進系（GPRCS）世界初の軌道上 HAN系推進薬 実証！ [Small Demonstration Satellite-1 RAPIS-1 Green Propellant Reaction Control System (GPRCS), the world's first on-orbit HAN propulsion system demonstration!] (in Japanese). JAXA. 15 March 2019. Retrieved 15 March 2019.
