Radioisotope Power Systems

Spacecraft require electrical energy. This energy must be available in the outer reaches of the solar system where sunlight is very faint. It must be available through lunar nights that last for 14 days, through long periods of dark and cold at the higher latitudes on Mars, and in high-radiation fields such as those around Jupiter. Radioisotope power systems (RPSs) are the only available power source that can operate unconstrained in these environments for the long periods of time needed to accomplish many missions, and plutonium-238 (238Pu) is the only practical isotope for fueling them. Plutonium-238 does not occur in nature. The committee does not believe that there is any additional 238Pu (or any operational 238Pu production facilities) available anywhere in the world.The total amount of 238Pu available for NASA is fixed, and essentially all of it is already dedicated to support several pending missions-the Mars Science Laboratory, Discovery 12, the Outer Planets Flagship 1 (OPF 1), and (perhaps) a small number of additional missions with a very small demand for 238Pu. If the status quo persists, the United States will not be able to provide RPSs for any subsequent missions.

This book describes the most complex machine ever sent to another planet: Curiosity. It is a one-ton robot with two brains, seventeen cameras, six wheels, nuclear power, and a laser beam on its head. No one human understands how all of its systems and instruments work. This essential reference to the Curiosity mission explains the engineering behind every system on the rover, from its rocket-powered jetpack to its radioisotope thermoelectric generator to its fiendishly complex sample handling system. Its lavishly illustrated text explains how all the instruments work -- its cameras, spectrometers, sample-cooking oven, and weather station -- and describes the instruments' abilities and limitations. It tells you how the systems have functioned on Mars, and how scientists and engineers have worked around problems developed on a faraway planet: holey wheels and broken focus lasers. And it explains the grueling mission operations schedule that keeps the rover working day in and day out.

Space Power Systems covers systems based on the three primary sources of energy of practical value, namely, solar, nuclear, and chemical sources. This book is organized into four parts encompassing 32 chapters that also explore the requirements for space power. Part A presents the general aspects of solar cell power systems based on the work performed for US space vehicles that are to be placed in orbit. This part specifically considers a graph showing the variation of characteristic parameters of the solar cell battery storage system as a function of flight altitude. Considerable chapters in this part are devoted to the solar cell power plant for the space vehicles ADVENT, RANGER, TIROS, and TRANSIT. The remaining chapters provide a detailed analysis of the physics and engineering of solar panel and solar mirror design. Part B contains a series of papers involving the various aspects of the Atomic Energy Commission SNAP (Systems for Nuclear Auxiliary Power) program. Many details are presented for the 3 kw, liquid metal, turbo-machinery SNAP II power systems covering subjects from the basic concept through vehicle integration and safety aspects. Significant chapters in this part discuss the compact and apparently highly reliable radioisotope thermoelectric generator. Part C highlights the methods of storing and expelling high energy cryogenic fuels, which can provide from two to five times more energy per unit weight than the silver-zinc primary battery. Part D provides an interesting and useful estimation of the many requirements that are likely to become firm for space vehicles. Space vehicle engineers, designers, and researchers will find this book invaluable.