The Physics of Negative Mass: applications for propulsion and interstellar travel Author: Geoffrey Landis, Ph.D., physicist, NASA John Glenn Research Center Abstract Background: As first analyzed by Hermann Bondi in 1957, matter with negative mass is consistent with the structure of Einstein’s general theory of Relativity. Although initially the concept was considered just a theoretical curiosity, negative mass, or “exotic matter,” is now incorporated into the body of mainstream physics in a number of forms. Negative mass has a number of rather non-intuitive properties, which, as first noted by Bondi, and then later commented on by Forward (1990), Landis (1991), and others, results in possible applications for propulsion requiring little, or possibly no, expenditure of fuel. As pointed out by Morris and Thorne (1988) and others, negative mass (or, more strictly, a violation of the null energy condition) is also a requirement for any proposed faster than light travel. This paper presents the basic theory of negative mass, the ways by which it can manifest in contemporary physical theory, and the counterintiutive properties that result, including possible uses for interstellar propulsion. to advanced propulsion. Abstract Objectives: The objective of this work is to summarize the physics of negative mass and the relevance and applications Abstract Methods: The work uses fundamental concepts of physics to analyze negative mass and its consequences for propulsion. Abstract Results: Although negative mass has moved from a theoretical curiosity to a concept fundamental to the contemporary understanding of physics, it is still not clear whether bulk negative mass can be manufactured, or if it is limited to only appearing at the cosmological scale (e.g., â€œdark energy:) or in the quantum (e.g., Casimir vacuum) limit. If it can be manufactured, the propulsion applications would be significant. TRL Assessment: TRL 1 Abstract Development: Still theoretical Abstract Near-Term Technical Milestones: Technolgical milestone: continue study in the context of theoretical physics and quantum mechanics. Abstract Conclusions: Although negative mass has moved from a theoretical curiosity to a concept fundamental to the contemporary understanding of physics, it remains a theoretical concept, not an engineering reality. If it can be manufactured, the propulsion applications would be significant.