The Future of Space Nuclear Power and Propulsion: A Retrospective JOHN E PIKE* AND STEVEN AFTERGOOD** Summary: Nuclear reactors have certain well-known characteristics that hold the potential for enabling a wide range of ambitious space missions. This potential has engaged enormous engineering and financial resources for four decades. But today, the most recent set of space nuclear power and propulsion programs is withering away, closely replicating the collapse of similar programs twenty years ago. This paper examines the cycle of enthusiasm followed by abandonment that has characterized space nuclear power and propulsion to date, contrasts it with the successful development of submarine nuclear propulsion, and attempts to elucidate the obstacles that a space nuclear technology development program must overcome. The future of space nuclear power and propulsion will depend on whether and how the "chicken and egg" impasse can be broken. Future aerospace nuclear reactors are likely to remain artist's concepts until they meet widely accepted requirements in a clearly superior manner. Introduction Compared to other space power supplies, nuclear reactors offer significant reductions in mass when power requirements exceed several tens of kilowatts. Furthermore, they are in principle more compact, long-lived, and survivable than competing concepts. For propulsion applications, nuclear reactors promise dramatic improvements in specific impulse. In short, space nuclear technology can be an enabling technology for many space missions. For the most part, however, space nuclear reactor programs have failed to deliver on this promise, despite decades of development and billions of dollars of investment. There are few fields of technological endeavor in which the historian's maxim — that the past is prologue -- is of greater relevance than the realm of space nuclear power and propulsion. There are at least three senses in which this is true: Many of the reactor and system concepts that are the subject of contemporary interest have been the subject of study and analysis for over three decades. While new permutations of these concepts have emerged over the years, there have been few * Director, Space Policy Project ** Senior Research Analyst Federation of American Scientists Washington, D C.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==