Ion Thrusters and Electrical Propulsion Developments

The transition from old space to new space along with increasing commercialization has a major impact on space flight in general and on electric propulsion by ion sources in particular. The requirements of space industry for electric propulsion systems, e.g., ion thrusters as well as their peripheral devices, change rapidly. We will discuss some of the major developments and corresponding research tasks arising. Commercialization implies mass production at a low price. This has at least two major impacts: (i) shorter product development cycles, i.e., new products should enter the market more rapidly, and (ii) resource efficiency become important. For example, shorter development times require that the qualification procedures for thruster systems need to be rethought. How much ground testing is necessary? How can modelling help to speed up qualification and to predict lifetimes and performance in space? Resource efficiency implies that scare materials should be avoided, e.g. xenon is scarce and not enough xenon is available as propellant for electric propulsion as a mass product, at least, not at a compatible price. Alternatives need to be sought. Are there suitable molecular propellants and what is the right strategy finding them? Is reactive iodine a cheap alternative to xenon as propellant? Prices of electric propulsion systems may also be considerably lowered by employing commercially available electronic components as part of the electric propulsion system. These components may have to be used beyond their specifications under extreme conditions, e.g., in the radiation environment of the Van-Allen belt. How to find suitable radiation-hard electronics? Formation flights of cheap and small satellites are an essential part of a data network. What does miniaturization imply? To which extent are current electric propulsion systems miniaturizable? How can electromagnet ic compatibility with the environment on the satellite be tested and guaranteed?