**Abstract**

One of the key potential technologies for generating high speeds in space is matter/ anti-matter annihilation. With the Compton effect, if positrons and electrons can be annihilated in a controlled way, and in sufficient quantities, then humans are able to achieve relativistic speeds in space. This chapter describes a technology, matter/ anti-matter propulsion, which is likely to enable the generation of relativistic speeds in space. To explain this technology, background information and prior efforts to promote matter/anti-matter annihilation as a propulsion source are introduced. Further, based on recent experiments conducted in the United States and Germany, the theoretical feasibility of generating relativistic speeds in space is explained. Finally, initial experiments designed to evaluate matter/anti-matter propulsion are described.

**Keywords:** matter, anti-matter, annihilation, Compton effect, relativity, relativistic speed, photon rocket
