The development and test of a hydrogen peroxide monopropellant microrocket engine using MEMS technology Richard Hebden 1 , Rich Bielby 1 , Adam Baker 2 , Sanjay Mistry 2 , Johan Köhler 3 , Lars Stenmark 3 , Berry Sanders 4 , Jean-Luc Moerel 4 , Wouter Halswijk 4 , Cor Rops 5 , Frederic Breussin 5 and Martin Lang 6 1 QinetiQ, Space Business Centre, Farnborough, Hampshire, GU14 0LX, United Kingdom. HBSimpson@space.qinetiq.com 2 Surrey Satellite Technology Ltd, Guildford, Surrey, GU2 7XH, United Kingdom. A.Baker@sstl.co.uk 3 ÅSTC, Dep. Engineering Sciences, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden. johan.kohler@angstrom.uu.se 4 TNO Defence, Security and Safety, Lange Kleiweg 137, PO Box 45, 2280 AA Rijswijk, The Netherlands, Berry.Sanders@tno.nl 5 TNO Science and Industry, Stieltjesweg 1, P.O. Box 155, 2600 AD Delft, The Netherlands, Frederic.Breussin@tno.nl 6 ESA-ESTEC, Chemical Propulsion Section Keplerlaan 1, PO Box 299, 2200 AG Noordwijk, The Netherlands, Martin.Lang@esa.int ABSTRACT Given the present, relatively limited deployment of low cost and mass space missions, there are clear opportunities for the application of small-scale propulsion systems in further enabling these small satellite missions. With this situation in mind, a team comprising ASTC, SSTL, TNO and QinetiQ – under funding from the European Space Agency – has undertaken the development of a MEMS-based micro-rocket engine concept with the intended capability of providing a specific impulse of greater than 100s. Both turbo-pump fed bi-propellant as well as mono propellant concepts were investigated. For demonstration a mono propellant design was selected of which an initial design concept was developed, based on hydrogen peroxide decomposition. Identified as the critical component in the mono-propellant system, several batches of the honeycomb wafers – upon which the decomposition occurs – have been manufactured. As a proof of concept, the wafers have been subjected to a set of structural and functionality tests. Given the results of the latest testing initiative, it is envisaged that, with adequate refinement and development of the current design, a reliable and deployable monopropellant micro-rocket engine solution may be realised. INTRODUCTION Given the present, relatively limited deployment of low-cost, low-mass space missions, there are clear opportunities for the application of small-scale propulsion systems in further enabling these small satellite missions. Requirements from Micro and nano satellites for constellation forming, LEO (low Earth orbit) drag compensation, manoeuvring for satellite inspection, formation flying, and end-of-life de-orbiting all indicate a need for significant ∆V (velocity change) capability from such a propulsion system, ideally coupled with high thrust levels, thus minimising energy losses. The requirement for such a technology is particularly evident when considering a problem commonly faced by low-cost missions; securing a precise orbit may often be compromised as a consequence of a shared or secondary launch. It is difficult to provide a suitable solution with conventionally engineered, miniature propulsion systems. Typically, these are expensive solutions, using toxic propellants that, in many cases, do not scale favourably to the sizes demanded by small satellite technology [1]. Micro System Technology based chemical propulsion is a candidate technology with the potential to fill the near term performance gap in the market for small satellites, defined by the lack of proposed systems providing an I sp in the range 100-300s. Such a system could conceivably be used for such tasks as orbit modification in micro- and nano-satellites, end-of-life de-orbit manoeuvring, and so on. Overview of MST propulsion research work Despite an increasing interest in miniaturised propulsion systems [2], very few MEMS-based chemical propulsion systems exist beyond the concept or breadboard stage. For example, the Ångström Space Technology Centre (ÅSTC) at Uppsala University has built and tested a MEMS hybrid system with a specific impulse (I sp ) of 45s, with up to 100s projected for future developments [3]. Further, the Gas Turbine Laboratory at MIT has undertaken an in-depth development programme with the objective of demonstrating a high performance bipropellant system with a target I sp of 300s, a thrust of 15N, and with propellant feed achieved using a MEMS-