To the End of the Solar System: The Story of the Nuclear Rocket

The vast amount of research and resources that went into the early years of the space race are truly astonishing. Parallel programs were duplicating missions and money was flowing out of Washington. The flagship programs of the era-Mercury, Gemini and Apollo were accompanied by lesser known successful programs like X-15 and by also rans like the Dyna-soar space plane and flights of fancy like the fantastic Orion space battleship. One major program that could be considered an also-ran is the Project Rover/Kiwi/NERVA nuclear rocket. The story of this remarkable technology is told in James Dewar’s “To the End of the Solar System”.

Basically, a nuclear rocket is one where the conventional combustion chamber is replaced with a nuclear show more reactor, enabling the use of lighter fuels at higher temperatures, thus increasing thrust or, as the rocketeers call it, specific impulse. The best chemical rockets can get to a specific impulse of 450. Nuclear engines start at about 850 and can go much higher. Thus, a spacecraft can have both better range on the same amount of fuel, or more speed with that fuel as a conventional rocket.

Dewar’s account alternates between the actual technical development of nuclear rockets and the Washington political machinations that kept the program going. The first real development of this technology, aside from some speculation by futurists in the 1930s and Los Alamos Manhattan Project scientist table talk was in the mid-1950s with concern about the range for the developing technology of ICBMs. With Sputnik and the real start of the space race, any technology that seemed promising was pursued to some degree. The nuclear rocket component of this was Project Rover. Rover found champions in Senators Clinton Anderson of New Mexico and Margaret Chase Smith of Maine, and to a lesser extent, Lyndon Johnson. Rover’s Kiwi and Phoebus engines were under constant scrutiny of budget hawks who saw it was a wasteful duplication of Apollo’s conventional engines. As Dewar relates, nuclear rocket engines consistently met or exceeded the goals that its designers set for it, and did so in a far faster timeframe than its designers originally estimated.

By the late 1960s nuclear engines were nearing maturity as a technology and its backers were hoping to keep it alive for NASA’s post-Apollo missions; a space station and for a manned Mars mission. First with the Johnson Administration’s attempt to have both a war in Vietnam and a massive buildup of social programs, then with the Nixon Administration backing away from space all together as a waste of money, NERVA as it was now called was on thin ice. It’s champions in congress were aging out and the new generation was not interested in space to the same degree. President Nixon attempted to kill it, only to see its last remaining champions retaliate by killing Nixon’s pet SST project. The next year, no money at all was allocated and NERVA was finished. There have been several brief revivals of nuclear rockets on paper, such as the SDI affiliated Project Timberwind, which being highly classified is not covered much in the book and since this book’s publication, DRACO (also cancelled). But it seems that nuclear rockets will inevitably come again as even with the advance in private reusable rocketry by SpaceX and Blue Origin, nothing can compete with the performance that this technology promises for interplanetary exploration.

To the End of the Solar System is an excellent account of what the back room bureaucratic, budgetary and political machinations are that accompany any major government project, as well as an interesting and detailed technical history for those who enjoy glimpsing the road not followed (at least not yet.) show less

This is the story about the nuclear rocket program that many hoped would be our key to deep space exploration. The story of the nuclear rocket is long and wandering. The book is comprehensive and very interesting. This book details key people, hardware and events that are critical to understanding the story as a whole. The only fault I could find is that I wished that more of the facilities associated with the program were explored, like the Plum Brook reactor, and others. I would recommend this to anyone interested in the space program, nuclear history, or so-out-there-it-can't-be-true non-fiction.