Doctoral Dissertations


"This dissertation presents work on development of multi-mode specific spacecraft propulsion systems. Specifically, this work attempts to realize a single propellant capable of both chemical monopropellant and electric electrospray rocket propulsion, develop methods to characterize multi-mode propulsion system performance, and realize a system capable of both monopropellant and electrospray propulsion for a small spacecraft. Selection criteria for ionic liquid propellants capable of both monopropellant and electrospray propulsion are developed. These are based on desired physical properties and performance considering use in both propulsive modes. From these insights, a monopropellant mixture of 1-ethyl-3-methylimidazolium ethyl sulfate and hydroxylammonium nitrate is selected and synthesized. Multi-mode spacecraft micropropulsion systems which include a high-thrust chemical mode and high-specific impulse electric mode are assessed. Due to the combination of a common propellant for both propulsive modes, low inert mass, and high electric thrust, the monopropellant/electrospray system has the highest mission capability in terms of delta-V for missions lasting shorter than 150 days. The ionic liquid monopropellant mixture is tested for decomposition on heated platinum, rhenium, and titanium surfaces. It was found that the propellant decomposes at 165 ⁰C on titanium, which is the decomposition temperature of HAN, and 85 ⁰C on platinum. Arrhenius-type reaction rate parameters were calculated from the results and used to develop thruster models. The [Emim] [EtSO4]-HAN propellant mixture is tested in a capillary electrospray emitter and exhibits stable electrospray emission at a nominal extraction voltage of 3400 V. The highest specific impulse attained in these experiments was 412 seconds; however, this could be improved with a more robust feed system design. This data, along with data from the monopropellant decomposition experiment is used to design a multi-mode micropropulsion system using a common propellant and common thruster geometry. This system is capable of ~20-40% greater delta-V capability at a given mission duration compared to a system utilizing separate, state-of-the-art monopropellant and electrospray thrusters"--Abstract, page iv.


Rovey, Joshua L.

Committee Member(s)

Köylü, Ümit Ö. (Ümit Özgür)
Pernicka, Hank
Prince, Benjamin
Riggins, David W.


Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Aerospace Engineering


Missouri University of Science and Technology

Publication Date

Fall 2015

Journal article titles appearing in thesis/dissertation

  • Assessment of imidazole-based ionic liquids as dual-mode spacecraft propellants
  • Assessment of multi-mode spacecraft micropropulsion systems
  • Decomposition of a double salt ionic liquid monopropellant on heated metallic surfaces
  • Electrospray of an energetic ionic liquid monopropellant for multi-mode micropropulsion applications


xiv, 149 pages

Note about bibliography

Includes bibliographic references.


© 2015 Steven Paul Berg, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 11358

Electronic OCLC #