The University of Southampton
Engineering and the Environment
(023) 8059 3881

Dr Charlie Ryan MEng, PhD

Lecturer in Astronautics

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Dr Charlie Ryan is a Lecturer in Astronautics, specializing in developing low cost micro-propulsion systems for small spacecraft. Has particular expertise in micro and mini electric propulsion, in particular electrospray thrusters and also low cost small hall-effect like thrusters. Also has an interest in chemical propulsion, particularly using hydrogen peroxide.

Spacecraft are becoming increasingly smaller and cheaper. My research is directed towards providing propulsion that can increase the capabilities of these small satellites.

Dates Career Summary
2015 -

University of Southampton

Lecturer in Astronautics

2014 -

University of Surrey

Post-doctoral Research Fellow, Surrey Space Centre, specializing in
developing low cost small electric propulsion systems for spacecraft.

2010 -

Queen Mary, University of London

Post-doctorate researcher - focusing on developing a MEMS electrospray
thruster for cubesats, as part of European Commission FP7 ‘MicroThrust’

2006 -

Queen Mary, University of London

PhD student – investigating theory of electrospray process from
experimental perspective. Thesis entitled ' Influence of electrostatics
upon electrospray with the intention of application to Colloid Thrusters’.

2002 -

University of Southampton

MEng Aeronautics and Astronautics student. Final degree specialised in
spacecraft propulsion.





Conference papers


Research interests

My research is broadly directed towards propulsion for micro and nano-satellites, using various types of propulsive techniques. These include but are not limited to; electrospray thrusters, mini hall effect thrusters, and chemical propulsion using hydrogen peroxide. I also have a strong interest in other applications of the electrospray technique, for example etching of Silicon, micro printing and medical applications. I also have an interest in applying plasma processes to novel fields of engineering and science.

Micro-electrospray Propulsion

The nano-satellite population in Low Earth Orbit has increased dramatically, with almost 120 launched in 2014. The majority of cubesats launched are now commercial rather than academic and scientific ventures, resulting in a need for more capable cubesats. One such capability missing currently from many cubesats is that of a propulsion system. Micro electrospray thrusters offer one such possible propulsion system. They operate by ions and charged droplets being attracted electrostatically out of fluid propellant present at the tip of an emitter, and then are accelerated through an electric field. Unlike many electric propulsion systems, they can be scaled down to fit within the confines of a cubesat. They still offer a highly capable system, with changes in velocity of the order of 100’s or 100’s of m/s feasible. They can be operated without the need of a neutraliser, and can be capillary fed reducing the need for a propellant feed system.

Current research into micro-electrospray thrusters is based on increasing the Technology Readiness Level of the system, towards a spaceflight ready model. This includes the improved fabrication of the emitters that form the electrospray process, especially so the accurate fabrication of large arrays that can in total emit a large enough current of charged species to result in an appreciable thrust. Other issues currently investigated are the suppression of electrochemical degradation, and the operation over longer periods that are necessary for the impulse accumulation on board a spacecraft.

Mini Hall Effect Thrusters

As with cubesats (nano-satelllites), larger micro-satellites suffer from a lack of capable electric propulsion systems that can fit within the confines of the satellite. With the large growth in micro-satellites, especially so with regard to proposed massive constellations, a propulsion system that can produce large changes in velocity would be highly useful. Typical electric propulsion systems are difficult to scale down to the sizes of micro and nano-satellites, thanks to space charge limitations and larger wall losses. Hall Effect thrusters, with some changes to the magnetic profile of the Hall Effect channel, can be scaled down to sizes and power requirements that are within the parameters of micro-satellites. This could make them ideally suited for micro-satellite constellations. Current areas of research include increasing the performance and lifetime of mini-Hall Effect thrusters, and investigation of alternative propellants which are cheaper and can more easily scale to fit within the propulsion subsystem for a micro-satellite.

Micro-electrospray arrays and their applications

Electrosprays typically have a low throughput, especially so when scaled down to emitters of 10’s of micron in diameter. To compensate for this low flow rate, arrays of electrospray emitters can be manufactured, multiplexing the flow rate of charged species. This is especially useful in micro-electrospray thrusters, but also has applications in other uses of electrospray devices. This includes but is far from limited to printing and accurate deposition, etching of Silicon, and electrospray mass spectrometry. By applying electrosprays arrays to for example mass spectrometry you can increase the signal to noise ratio of the sample. Novel manufacturing methods are being exploited for alternative uses of electrosprays, with designs tailored to specific applications.

Research group


Programme Leader – SESA6071 Spacecraft Propulsion


Programme Leader – SESA6071 Spacecraft Propulsion

Wantock T, Ryan CN, Harle T, Knoll A. 2015. Initial performance characterisation of a plasma thruster employing magnetic null regions. To be presented at Joint Conference of 30th International Symposium on Space Technology and Science, 34th International Electric Propulsion Conference and 6th Nano-satellite Symposium Hyogo-Kobe, Japan July 4–10.

Ryan CN, Daykin-Iliopoulos A, Stark JPW, Salaverri A, Vargas E, Rangsten P, Timmerman J, de Jong M, Visee R, van Vliet L, Sanders B, Straathof M, Tata Nardini F, van Pul-Verboom V, Dandavino S, Ataman C, Chakraborty S, Courtney D, Belloni F, Pirat C, Richard M, and Shea H. 2014 The MicroThrust MEMS electrospray thruster: results and conclusions. AAAF-ESA-CNES Space Propulsion Conference, Cologne, Germany, 19th – 22th May. Presented in person

Ryan CN, Daykin-Iliopoulos A, Stark JPW, Salaverri A, Vargas E, Rangsten P, Dandavino S, Ataman C, Chakraborty S, Courtney D, Shea H. 2013 Experimental progress towards the MicroThrust MEMS electrospray electric propulsion system. 33rd International Electric Propulsion Conference, Washington DC USA, 6-10th October. Presented in person

Dandavino S, Ataman C, Chakraborty S, Shea H, Ryan CN, Stark JPW. 2013 Design and fabrication of the thruster heads for the MicroThrust MEMS electrospray propulsion system. 33rd International Electric Propulsion Conference, Washington DC USA, 6-10th October.

Dandavino S, Ataman C, Chakraborty S, Shea H, Ryan CN, Stark JPW. 2012 Progress towards a miniaturized electrospray thruster for propulsion of small spacecraft. 48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, Atlanta Georgia, 30 July - 01 August.

Ryan CN, Stark JPW, Dandavino S, Ataman C, Chakraborty S, Shea H. 2012 MicroThrust MEMS electrospray emitters - integrated microfabrication and test results. AAAF-ESA-CNES Space Propulsion Conference, Bordeaux France, 7-10th May. Presented in person

Nardini FT, Sanders B, Straathof M, Ataman C, Richard M, Shea H, Rangsten P, Salaverri A, Ryan CN, Stark JPW, Visée R. 2012 Development of the Microthrust breadboard: a miniaturised electric propulsion system for nanosatellites. AAAF-ESA-CNES Space Propulsion Conference, Bordeaux France, 7-10th May.

Grönland T, Rangsten P, Salaverri A, Vargas E, Nardini FT, Straathof M, Ryan CN, Stark JPW, Visée R, Ataman C, Richard M, Shea H. 2012. MEMS-based electric micropropulsion for small spacecraft to enable robotic space exploration and space science (MicroThrust). Small Satellites Systems and Services - The 4S Symposium 2012, Portorož Slovenia, 4-8th June. Poster presentation

Dandavino S, Ataman C, Shea H, Ryan CN, Stark JPW. 2011 Microfabrication of capillary electrospray emitters and ToF characterization of the emitted beam. 32nd International Electric Propulsion Conference, Wiesbaden Germany, 11-15th September.

Ryan CN, Smith KL, Alexander MS, Stark JPW. 2009 Performance modulation of colloid thrusters by the variation of flow rate with applied voltage. 31st International Electric Propulsion Conference, Ann Arbor Michigan, 20-24th September. Presented in person

Musker A, Roberts G, Horabin R, Kawar A, Payne M, Pollard M, Ryan CN. 2006 An Assessment of Homogeneous Catalysts for the Rapid Decomposition of Hydrogen Peroxide. 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, Sacramento California, 9-12th July.


Dr Charlie Ryan
Engineering and the Environment University of Southampton Highfield Southampton SO17 1BJ

Room Number:13/5041

Telephone:(023) 8059 3881

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