Chapter 20. Nuclear Propulsion
Nuclear processes are logical choices for compact energy sources in vehicles that must travel long distances without refueling. The most successful application is in the propulsion of naval vessels, especially submarines and aircraft carriers. Thermoelectric generators that use the isotope plutonium-238 provide reliable electric power for interplanetary spacecraft. Research and development has been done on reactors for aircraft and rockets, and reactors may be used in future missions.
20.1. Reactors for Naval Propulsion[†]
The discovery of fission stimulated interest on the part of the United States Navy in the possibility of the use of nuclear power for submarine propulsion. The development of the present fleet of nuclear ships was due largely to Admiral H. G. Rickover, a legendary figure because of his reputation for determination, insistence on quality, and personalized management methods. The team that he brought to Oak Ridge in 1946 to learn nuclear technology supervised the building of the land-based prototype at Idaho Falls and the first nuclear submarine, Nautilus. As noted by historians for the project (see References), the name had been used for submarines before, including Jules Verne's fictional ship.
† Thanks are due Commander (Ret.) Marshall R. Murray, USN, for some of the information in this section.
The principal virtue of a nuclear-powered submarine is its ability to travel long distances at high speed without refueling. It can remain submerged because the reactor power plant does not require oxygen. Research on the Submarine Thermal Reactor was conducted by Argonne National Laboratory, and the development was carried out at the Bettis Laboratory of Westinghouse Electric Corporation.
The power plant for the Nautilus was a water-moderated, highly enriched uranium core with zirconium-clad plates. The submarine's first sea trials were made in 1955. Some of its feats were a 1,400-mile trip with an average speed of 20 knots, the first underwater crossing of the Arctic ice cap, and traveling a distance of more than 62,000 miles on its first core loading. Subsequently the Triton reproduced Magellan's trip around the world, but completely submerged. The Nautilus was decommissioned in 1980 and is now in a museum at Groton, CT.
Over the years of the Cold War, the United States nuclear fleet was built up, with more than 100 nuclear-powered submarines and a number of aircraft carriers. The first of the latter was the Enterprise, deployed in 1961. It has eight reactors, 85 aircraft, and 5,830 men. Figure 20.1 shows the carrier with Einstein's familiar formula spelled out on the deck by members of the crew. Since then, several additional carriers have been built, some of which saw service in the Gulf War and subsequent military activities.
Figure 20.1. The nuclear-powered aircraft carrier USS Enterprise. Sailors in formation on the flight deck spell out Einstein's formula. The accompanying ships are the USS Long Beach and the USS Bainbridge
(Courtesy United States Navy).
Attack submarines are designed to seek and destroy enemy submarines and surface ships. In 1995 the Seawolf was launched. It was powered with one reactor and armed with Tomahawk cruise missiles. Ballistic missile submarines are designed as deterrents to international conflict. Examples are the Ohio-class, which carry 24 long-range Trident strategic missiles (see References). These weapons can be ejected by compressed air while the vessel is under water, with the rocket motors started when the missile clears the surface. The number of United States nuclear-powered naval vessels is gradually being reduced by obsolescence and decision, and by international agreement, as part of the START program (see Section 26.3).
Commercial nuclear power has benefited in two ways from the Navy's nuclear program. First, industry received a demonstration of the effectiveness of the pressurized water reactor. Second, utilities and vendors have obtained the talents of a large number of highly skilled professionals who are retired officers and enlisted men.
The United States built only one commercial nuclear vessel, the merchant ship N.S. Savannah. Its reactor was designed by Babcock & Wilcox Company Carrying both cargo and passengers, it was successfully operated for several years in the 1960s, making a goodwill voyage to many countries (see References). After being on display at a naval museum in South Carolina, the N.S. Savannah was moved in 1994 to Virginia as a national landmark.
Several icebreakers powered by nuclear reactors were built by the U.S.S.R. and continue to be used in the far north for expedition cruises (see References). The newest and most powerful Russian icebreaker is the 50 Years Since Victory.
Japan launched an experimental nuclear-powered merchant ship Mutsu in 1962. It successfully passed several rigorous sea trials, performing well in rough seas caused by a typhoon. Decommissioned in 1995 and placed in a museum, its experience served as the basis for the design of two other vessels (see References).
20.2. Space Reactors
Many years before the advent of the space program, an attempt was made to develop an aircraft reactor. A project with the acronym NEPA (Nuclear Energy for the Propulsion of Aircraft) was started at Oak Ridge in 1946 by the United States Air Force. The basis for the program was that nuclear weapon delivery would require supersonic long-range (12,000 miles) bombers not needing refueling. An important technical question that still exists is how to shield a crew without incurring excessive weight. As described by Hewlett and Duncan (see References), the program suffered from much uncertainty, changes of management, and frequent redirection. It was transferred from Oak Ridge to Cincinnati under General Electric as the Aircraft Nuclear Propulsion (ANP) program. The effort was terminated for several reasons: (a) the need for a much larger airplane than expected, (b) improvements in performance of chemically fueled jet engines, and (c) the selection of intercontinental ballistic missiles to carry nuclear weapons. Some useful technical information had been gained, but the project never came close to its objective.
The space program was given new impetus in 1961 with President Kennedy's goal of a manned lunar landing. Other missions visualized were manned exploration of the planets and ultimately colonization of space. For such long voyages requiring high power, the light weight of nuclear fuel made reactors a logical choice for both electrical power and propulsion. One concept that was studied extensively was ion propulsion, with a reactor supplying the energy needed to accelerate the ions that give thrust. A second approach involved a gaseous core reactor, in which a mixture of uranium and a gas would be heated by the fission reaction and be expelled as propellant. Another more exotic idea was to explode a number of small nuclear weapons next to a plate mounted on the space vehicle, with the reaction to the explosion giving a repetitive thrust.
Fission reactors with thermoelectric conversion systems were developed in the period 1955–1970 by the Atomic Energy Commission. Its contractor, Atomics International, conducted the Systems for Auxiliary Nuclear Power (SNAP) program. The most successful of these was SNAP-10A, which was the first and only United States reactor to be flown in space. Two systems were built—one tested on Earth, the other put in orbit. Their fuel was an alloy of enriched uranium and zirconium hydride to operate at high temperatures (810 K). The coolant was liquid sodium-potassium (NaK) for efficient heat transfer. The NaK was circulated through the reactor and a thermoelectric converter system that produced 580 watts of electrical power. The total weight of one system was 435 kg. The space version was launched in 1965 by an Agena rocket and started up by remote control. It operated smoothly in orbit for 43 days until it was accidentally shut down by an electric failure in the spacecraft. The ground version operated satisfactorily for 10,000 h. Further details are provided by Bennett (see References). Another successful reactor SNAP-8 used mercury as coolant, with conversion to 50 kW of electric power in a Rankine cycle. Further details of these reactors appear in the book by Angelo and Buden (see References).
The nuclear system that received the most attention in the space program was the solid core nuclear rocket. Liquid hydrogen would be heated to a high temperature as gas on passing through holes in a reactor with graphite moderator and highly enriched uranium fuel. In the proposed vehicle the hydrogen would be exhausted as propellant through a nozzle.
The nuclear thermal rocket sketched in Figure 20.2 is a relatively simple device. Hydrogen propellant is stored in a tank as a liquid. The reason that space travel by nuclear rocket is advantageous can be seen from the mechanics of propulsion. The basic rocket equation relating
spacecraft velocity υ, fuel exhaust velocity υf, and the masses of the full and empty rocket m0 and m, is
or the inverse relation
with the mass of vehicle plus payload being m0 − m. The burning products of a chemical system are relatively heavy molecules, whereas a nuclear reactor can heat light hydrogen
gas. Thus for a given temperature, υf is much larger for nuclear and m is closer to m0 (i.e., less fuel is needed).
Figure 20.2. Nuclear-thermal rocket system. Hydrogen stored in liquid form is heated in the solid core and expelled as propellant.
(Courtesy Gary Bennett).
To escape from the Earth or from an orbit around the Earth requires work to be done on the spacecraft against the force of
gravity. The escape velocity υe for vertical flight is
where g0 is the acceleration of gravity at the Earth's surface, 32.174 ft/s2 or 9.80665 m/s2, and rE is the radius of the Earth, approximately 3,959 miles or 6,371 km. Inserting numbers we find the escape velocity to be approximately
36,700 ft/s, 25,000 mi/h, or 11.2 km/s.
The Rover project at Los Alamos was initiated with a manned mission to Mars in mind. Flight time would be minimized with hydrogen as propellant, because its specific impulse would be approximately twice that of typical chemical fuels. A series of reactors named Kiwi, NRX, Pewee, Phoebus, and XE′ were built and tested at the Nuclear Rocket Development Station located in Nevada. The systems used uranium carbide fuel, graphite moderator, and once-through hydrogen coolant, entering as a liquid and leaving as a gas. The best performance obtained in the Nuclear Engine for Rocket Vehicle Application (NERVA) program was a power of 4,000 MW for 12 min. The program was a technical success but was terminated in 1973 because of a change in NASA plans. After the lunar landing in the Apollo program, a decision was made not to have a manned Mars flight. It was judged that radioisotope generators and solar power would be adequate for all future space needs.
Various R&D programs on space reactors to provide electric power were initiated subsequently (e.g., the SP-100), which was to be a reactor in the 100 kW to 1 MW range. Most of the projects were eventually canceled.
20.3. Space Isotopic Power
Chemical fuels serve to launch and return space vehicles such as the shuttle. For long missions such as interplanetary exploration, where it is necessary to supply electric power to control and communication equipment for years, nuclear power is needed. The radioisotope thermoelectric generator (RTG) has been developed and used successfully for many missions. It uses a long-lived radionuclide to supply heat that is converted into electricity. The power source has many desirable features: (a) lightness and compactness, to fit within the spacecraft readily; (b) long service life; (c) continuous power production; (d) resistance to environmental effects such as the cold of space, radiation, and meteorites; and (e) independence from the sun, permitting visits to distant planets.
The isotope used to power the RTGs is plutonium-238, half-life 87.74 y, which emits alpha particles of 5.5 MeV. The isotope is produced by reactor neutron irradiation of the almost-stable isotope neptunium-237, half-life 2.14 × 106 y. The latter is a decay product of uranium-237, a 6.75-d beta emitter that arises from neutron capture in uranium-236 or by (n,2n) and (γ,n) reactions with uranium-238. The high-energy alpha particles and the relatively short half-life of Pu-238 give the isotope the high specific activity of 17 Ci/g and the favorable power to weight ratio quoted to be 0.57 W/g.
The earliest use was in Pioneer 10, launched in 1972 and Pioneer 11, launched in 1973. The missions were to explore Jupiter. The last radio signal from Pioneer 10 was received on January 22, 2003. The spacecraft was then 7.6 billion miles from Earth, after more than 30 y in space. It was powered by an RTG of initial power 160 W along with several one-watt radioisotope heater units (RHUs). The two spacecraft are at the edge of the solar system and experiencing an unexplained slowing, the “Pioneer Anomaly.” Reasons advanced for the effect include thermal recoil, gravity from the Kuiper Belt, “dark matter,” and new physics.
Typical of the RTGs is the one sent to the Moon in the Apollo-12 mission. It powered a group of scientific instruments called Apollo Lunar Surface Experimental Package (ALSEP), which measured magnetic fields, dust, the solar wind, ions, and earthquake activity. The generator is shown schematically in Figure 20.3. Lead-telluride thermoelectric couples are placed between the PuO2 and the beryllium case. Data on the generator are shown in Table 20.1.
Figure 20.3. Isotopic electrical power generator. (SNAP-27 used in Apollo-12 mission).
Table 20.1. Radioisotope Thermoelectric Generator SNAP-27
| System weight 20 kg | Thermal power 1480 W |
| Pu-238 weight 2.6 kg | Electrical power 74 W |
| Activity 44,500 Ci | Electrical voltage 16 V |
| Capsule temperature 732 °C | Operating range −173 °C to 121 °C |
This generator, called SNAP-27, was also used in several other Apollo missions, and data were returned to Earth for the period 1969–1977. For the 1975 Viking mission, the somewhat smaller SNAP-19 powered the Mars landers, which sent back pictures of the surface of that planet.
An advanced model, called multi-hundred watt (MHW), provided all electrical power for the two Voyager spacecraft (Figure 20.4), designed and operated by the Jet Propulsion Laboratory of NASA. They were launched in the summer of 1977 and reached Jupiter in 1979 and Saturn in late 1980 and early 1981, sending back pictures of Saturn's moons and rings. Voyager 1 was then sent out of the solar system to deep space. Taking advantage of a rare alignment of three planets, Voyager 2 was redirected to visit Uranus in January 1986. The reliability of the power source after 9 y in space was crucial to the mission. Because of limited light at 1.8 billion miles from the Sun, long exposure times of photographs and thus great stability of the spacecraft were needed. By sending radio signals to Voyager 2, the onboard computers were reprogrammed to allow very small corrective thrusts (see References). Several new moons of Uranus were discovered, including some whose gravity stabilizes the planet's rings. Voyager 2 arrived at Neptune in 1989; it then went on to outer space. The MHW generator used silicon-germanium as thermoelectric material rather than lead-telluride; each generator was heavier and more powerful than SNAP-27. Similar power supplies are used for the Lincoln Experimental Satellites (LES 8/9), which can communicate with each other and with ships and aircraft.
Figure 20.4. Voyager 2 spacecraft as it passed Saturn in 1981.
(Courtesy National Aeronautics and Space Administration).
A still larger supply, called General Purpose Heat Source (GPHS), was used in the Galileo spacecraft sent out in October 1990 toward Jupiter. On its way it photographed the asteroids Gaspra and Ida, viewed the impacts of the Shoemaker-Levy 9 comet on the surface of Jupiter, and made flybys of moons Io and Europa. A battery-powered instrumented probe was sent down through Jupiter's atmosphere. Photographs and further information have been provided by NASA (see References). Studies of this distant planet complement those made of nearby Venus by the solar-powered Magellan. Pictures of the moon Europa indicate an icy surface of a liquid ocean. The mission ended when the spacecraft entered Jupiter's heavy atmosphere.
The spacecraft Ulysses, launched in November 1990, is also powered by a GPHS. It is a cooperative mission between the United States and Europe to study the solar wind—a stream of particles from the Sun—and the star's magnetic field. Ulysses will rendezvous with Jupiter to use the planet's gravity to take the spacecraft out of the ecliptic (the plane in which the planets move).
The Cassini spacecraft, launched in 1997 toward Saturn and its moon Titan, contains three RTGs to power instruments and computers, each with approximately 10.9 kg of PuO2. The total power was initially 888 W. In addition to radio power, RTGs were used to keep the electronic components warm. Unusual views of the planet's rings were obtained. The accompanying Huygens probe landed on Titan. Details on the spacecraft and its instrumentation are found on the Web site of NASA (see References).
The spacecraft New Horizons was launched in 2006 to go past Jupiter to Pluto in 2015 and the Kuiper Belt in 2016–2020. There, many planetary objects will be encountered (see References).
To help maintain proper temperatures for sensitive electronic components, small (2.7 g, 1 W) Pu-238 sources—radioisotope heating units (RHUs)—are provided. These were used in the missions to distant planets and also in the Sojourner minirover that explored the surface of Mars (see References).
Power supplies planned for missions of the more distant future will be in the multikilowatt range, have high efficiency, and make use of a different principle. In the dynamic isotope power system (DIPS), the isotopic source heats the organic fluid Dowtherm A, the working fluid for a Rankine thermodynamic cycle, with the vapor driving a turbine connected to an electric generator. In a ground test the DIPS operated continuously for 2000 h without failure. Details of all of these RTGs are given in the book by Angelo and Buden (see References).
Long-range missions for the 21st century planned by NASA include the recovery of resources at a lunar base and from an asteroid, a space station orbiting the Earth, and eventually a manned Mars mission. Such activities will require nuclear power supplies in the multimegawatt range.
Other isotopes that can be used for remote unattended heat sources are the fission products strontium-90 in the form of SrF2 and cesium-137 as CsCl. When the use of an oil-fired power unit is not possible because of problems in fuel delivery or operability, an isotopic source is very practical, despite the high cost. If the two isotopes were extracted by fuel reprocessing to reduce the heat and radiation in radioactive waste, many applications would surely materialize.
Success with power sources for space applications prompted a program to develop a nuclear-powered artificial heart. It involved a Pu-238 heat source, a piston engine, and a mechanical pump. The research program was suspended and is unlikely to be revived, with the advent of battery-powered implantable artificial hearts (see References).
20.4. Future Nuclear Space Applications
The extent to which nuclear processes are used in space depends on the degree of commitment to a space program. Over the years, United States enthusiasm for space programs has varied greatly. The Russian Sputnik of 1957 prompted a flurry of activity; President Kennedy's proposal to put a man on the Moon gave the space effort new impetus. Public support has waned, as launches became more routine and new national social problems gained prominence. The Challenger tragedy of 1986 resulted in a loss of confidence in NASA and was a setback to plans for new missions.
In 1989, President George H. W. Bush announced a new program called Space Exploration Initiative (SEI), involving return to the Moon and establishing a base there, then to make a manned trip to the planet Mars. A report by the Synthesis Group (see References) discussed justification and strategies. One nuclear aspect of the project was the possibility of mining helium-3 from the surface of the Moon for use in fusion reactors, as discussed in Section 14.5. The proposed SEI program was not accepted by Congress, and more modest NASA activities involving unmanned spacecraft such as Mars Pathfinder took its place. The exploration of the surface of Mars by the remotely controlled Sojourner minirover was viewed on television by millions of people.
President George W. Bush revived prospects for a Mars mission. The first step would be to return to the Moon. The objective would be exploration for scientific knowledge, to prepare for a base there, and to gain experience relevant to a human visit to Mars. The method by which travel would be made has not been firmed up. Originally, a nuclear rocket of the NERVA type (see Section 20.2) was considered. Later, electric propulsion with ions providing thrust was proposed, and still later matter–antimatter annihilation energy generation was suggested. However, NASA has indicated that a Mars mission would only be around 2037. Some believe that a manned trip to an asteroid would be easier and less expensive.
Whatever the mode of transport to Mars, it is presumed that an initial unmanned vehicle would carry cargo, including a habitat and a reactor for power on the planet's surface. Both timing and duration are important factors for a manned mission. Travel to Mars would take approximately 160 d, allowing 550 d for exploration, until the planets are in correct position for return, which would take 160 d again. Only nuclear power is available for such a schedule. For the descent and ascent between Mars orbit and the planet's surface, chemical rockets would be needed. Studies of geology and microbiology would be carried out, investigating further the possibility of life forms. The fuel produced on Mars—methane (CH4) and liquid oxygen—would come from the thin CO2 atmosphere and the supply of H2 brought from Earth.
For power to process materials on the Moon, a small reactor might be used. Potential resources include water, oxygen, and hydrogen. With adequate heat, the fine dust (regolith) that covers the surface could be formed into solid for construction and radiation shielding. Helium-3 as a fuel for a fusion reactor could be recovered for return to Earth.
Computer Exercise 20.B describes two simple programs that simulate planetary motion.
Calculations of trajectory can be made with the program ORBIT1, described in Computer Exercise 20.A.
The Challenger shuttle accident in 1986 resulted in increased attention to safety. It also raised the question as to the desirability of the use of robots for missions instead of human beings. The benefit is protection of people from harm; the disadvantage is loss of capability to cope with unusual situations. Among the hazards experienced by astronauts are high levels of cosmic radiation outside the Earth's atmosphere, possible impacts of small meteorites on the spacecraft, debilitating effects of long weightlessness, and in the case of a nuclear-powered vehicle, radiation from the reactor. If a reactor were used for transport, to avoid the possibility of contamination of the atmosphere with fission products if the mission is aborted, the reactor would be started only when it is safely in Earth orbit.
For power supplies that use radioisotopes, encapsulation of the Pu-238 with iridium and enclosing the system with graphite fiber reduces the possibility of release of radioactivity. For space missions, risk analyses analogous to those for power reactors are carried out.
Some time in the distant future, electric propulsion may be used. Charged particles are discharged backwards to give a forward thrust. Its virtue is the low mass of propellant that is needed to permit a larger payload or a shorter travel time. Several possible technologies exist: (a) electrothermal, including arcjets and resistojets (in which a propellant is heated electrically), (b) electrostatic, which uses an ion accelerator, or (c) electromagnetic, such as a coaxial magnetic plasma device. The distinction between electric propulsion and thermal propulsion is in the ratio of thrust and flow rate of propellant, which is the specific impulse, Isp. For example, the shuttle launcher has a high thrust but also a high flow rate, and its Isp is approximately 450 s. Electric propulsion has a low thrust but a very low flow rate, giving an Isp of some 4000 s.
Research on the Hall Thruster, an ion engine, is in progress at Princeton Plasma Physics Laboratory. Electrons are injected to neutralize space charge and permit heavy ion flow to provide thrust (see References).
Prospects for nuclear power for space propulsion have waxed and waned over many decades. A recent development is Project Prometheus, which was designed to use a nuclear reactor as a power source, driving an ion engine that expels xenon ions for its thrust. The engine was successfully tested on the ground in 2003. Speeds were expected to be up to 200,000 miles per hour, 10 times that of the space shuttle. The system was originally intended for an exploration of Jupiter's icy moons, but the mission was shifted to the Earth's moon. Note that present Web sites mainly refer to the original plan. For a 2005 account, search for “NASA's Prometheus.” A decision was then made to suspend or possibly abandon Prometheus in favor of some other approach. The ion engine concept will be retained, however. The spacecraft Dawn, launched in 2007 toward asteroids Vesta and Ceres, has solar-powered ion engines rather than an RTG, but its detectors are unique. The 21 sensors measure cosmic ray gammas and neutrons that bounce off the asteroids, providing information about composition.
The asteroid Apophis, 390 m wide, is predicted to come very close to Earth in 2029 and 2036. Various proposed techniques to prevent a catastrophic collision include nudging it into a new path with a nuclear-powered spacecraft. Destruction by a nuclear weapon is not favored because the fragments would still strike the Earth.
Looking into the very distant future, some scientists contemplate the “terraforming” of Mars by the introduction of chemicals that change the atmosphere and ultimately permit the normal existence of life forms. Finally, the vision is always present of manned interstellar travel, paving the way for colonization of planets outside our solar system. The discovery of a number of stars with planets has given encouragement to that idea.
What the future of nuclear applications in space will be depends on the accomplishments and aspirations of mankind in space. The urge to investigate and understand is a strong and natural aspect of the human psyche, and some say it is desirable or necessary to plan for interplanetary colonization. Supporters of space exploration cite its many spinoff benefits. Others remind us that there are many serious problems on Earth that need attention and money. How to balance these views remains an issue to be resolved by the political process.
20.5. Summary
Nuclear reactors serve as the power source for the propulsion of submarines and aircraft carriers. Tests of reactors for aircraft and for rockets have been made, and reactors are being considered for future space missions. Thermoelectric generators that use plutonium-238 provided electric power for lunar exploration in the Apollo program and for interplanetary travel of the spacecrafts Voyager, Galileo, Ulysses, and Cassini.
20.6. Exercises
- (a) Verify that plutonium-238, half-life 87.7 y, α-particle energy 5.5 MeV, yields an activity of 17 Ci/g and a specific power of 0.57 W/g. (b) How much plutonium would be needed for a 200 microwatt heart pacemaker?
- Note that the force of gravity varies inversely with r2 and that centrifugal acceleration balances gravitational attraction for an object in orbit. (a) Show that the velocity of
a satellite at height h above the Earth is
where g0 is the acceleration of gravity at the surface of the Earth, of radius rE. (b) Calculate the velocity of a shuttle in orbit at 100 miles above the Earth. (c) Derive a formula and calculate h in miles and kilometers for a geosynchronous (24 h) communications satellite.
- If the exhaust velocity of rocket propellant is 11,000 ft/s (3.3528 km/s), what percent of the initial mass must be fuel for vertical escape from the Earth?
Computer Exercises
- The initial velocity of a rocket ship determines whether it falls back to Earth, goes into orbit about the Earth, or escapes
into outer space. The program ORBIT1 calculates the position of a spacecraft and its distance from the center of the Earth
for various input values of the starting point and velocity.
- To view the motions of Earth and Mars about the Sun, run the program PLANETS.
- To see numerical features of the relative motion of the planets over the years, run the program PLANETS1. Verify that the phase differences are 0 ° and 180 ° when the planets are in conjunction and in opposition, respectively. Find out how many years it takes to return to the initial phase difference of 44.3 °.
- A trip to Mars will probably be made in a spacecraft assembled in orbit around the Earth at altitude of, say, 100 miles (160.9 km). Find its initial speed with the formula for υs in Exercise 20.2. What is its period, as the time for one revolution? With computer program ALBERT from Chapter 1, find the fractional increase of mass of the ship (and the astronauts) at that speed. Recall that the radius of the Earth is 6378 km.
20.7 References
Hewlett and Duncan, 1974 Richard G. Hewlett, Francis Duncan, Nuclear Navy 1946–1962 1974 University of Chicago Press Chicago
Anderson and Blair, 1959 William R. Anderson U.S.N., Clay Blair Jr., Commander Nautilus-90-North 1959 World Publishing Co Cleveland An account by the chief officer of the nuclear submarine Nautilus of the trip to the North Pole
Nautilus Museum Nautilus Museum
http://www.ussnautilus.org http://www.ussnautilus.org
History, tour, and links History, tour, and links.
Nuclear-powered ships Nuclear-powered ships
http://www.uic.com.au/nip32.htm http://www.uic.com.au/nip32.htm
Submarines, naval fleets, civil vessels, and power plants Submarines, naval fleets, civil vessels, and power plants.
United States Submarine Classes United States Submarine Classes
http://www.milnet.com/pentagon/subclass.htm http://www.milnet.com/pentagon/subclass.htm
Descriptions of vessels Descriptions of vessels.
United States Attack Submarines United States Attack Submarines
http://www.navsource.org/archives/08/05idx.htm http://www.navsource.org/archives/08/05idx.htm
Specifications, histories, and photographs Specifications, histories, and photographs.
Center for Defense Information (CDI) Center for Defense Information (CDI)
http://www.cdi.org/issues/naval/seawolf.html http://www.cdi.org/issues/naval/seawolf.html
http://www.cdi.org/issues/nukef&f/database/usnukes.html#ohio http://www.cdi.org/issues/nukef&f/database/usnukes.html#ohio
Information on nuclear naval vessels Information on nuclear naval vessels.
Simpson, 1994 John W. Simpson, Nuclear Power from Underseas to Outer Space 1994 American Nuclear Society La Grange Park, IL History of the development of the nuclear submarine Nautilus, the first commercial nuclear power plant at Shippingport, and the nuclear thermal rocket engine, NERVA.
Rockwell, 1992 Theodore Rockwell, The Rickover Effect: How One Man Made a Difference 1992 Naval Institute Press Annapolis Describes the key role Admiral Rickover had in the United States Navy's nuclear submarine program and the first nuclear power plant
Adams Atomic Insights on N. S. Savannah Adams Atomic Insights on N. S. Savannah
http://www.atomicinsights.com/AEI_home.html http://www.atomicinsights.com/AEI_home.html
Select Topical Index/Nuclear Ships Select Topical Index/Nuclear Ships. Additional information by Rod Adams.
https://voa.marad.dot.gov/programs/ns_savannah/index.asp https://voa.marad.dot.gov/programs/ns_savannah/index.asp
History, decommissioning, and preservation History, decommissioning, and preservation.
Nuclear-powered Icebreaker Nuclear-powered Icebreaker
Google “nuclear icebreaker Yamal” Google “nuclear icebreaker Yamal”
Specs on ship and cruise to North Pole Specs on ship and cruise to North Pole.
Japanese Nuclear Ship Mutsu Japanese Nuclear Ship Mutsu
http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/tayu/ACT95E/06/0601.htm http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/tayu/ACT95E/06/0601.htm
Specifications and history Specifications and history.
http://www.osti.gov/accomplishments/rtg.html http://www.osti.gov/accomplishments/rtg.html
Links to many documents Links to many documents.
http://www.nuclearspace.com http://www.nuclearspace.com
Articles, opinion, and interviews Articles, opinion, and interviews.
Gary Bennett, “Space Nuclear Power: Opening the Final Frontier” Gary Bennett, “Space Nuclear Power: Opening the Final Frontier”
http://www.fas.org/nuke/space/bennett0706.pdf http://www.fas.org/nuke/space/bennett0706.pdf
A spectacular paper, 2006 A spectacular paper, 2006.
Nuclear Power in Space Nuclear Power in Space
http://www.ne.doe.gov/pdfFiles/NPSPACE.PDF http://www.ne.doe.gov/pdfFiles/NPSPACE.PDF
Review of all missions by Department of Energy Review of all missions by Department of Energy.
El-Genk, 1994 Mohamed S. El-Genk, A Critical Review of Space Nuclear Power and Propulsion, 1984–1993 1994 AIP Press New York Includes papers on radioisotope generators and nuclear thermal propulsion.
Angelo and Buden, 1985 Joseph A. Angelo Jr, David Buden, Space Nuclear Power 1985 Orbit Book Co Malabar, FL A definitive textbook
Angelo, 2001 Joseph A. Angelo Jr, Encyclopedia of Space and Astronomy 2001 Facts on File New York
Laeser et al., November, 1986 Richard P. Laeser, William I. McLaughlin, Donna M. Wolff, “Engineering Voyager 2's Encounter with Uranus,” Scientific American November 198636- Discusses the power problem caused by decay of Pu-238 in RTGs
Miner, July 1990 Ellis D. Miner, Voyager 2's Encounter with the Gas Giants Physics Today July 199040-
Pioneer Anomaly Pioneer Anomaly
http://www.planetary.org http://www.planetary.org
Unexplained slowing of the spacecraft Unexplained slowing of the spacecraft. Select The Pioneer Anomaly.
Galileo Mission Galileo Mission
http://www2.jpl.nasa.gov/galileo http://www2.jpl.nasa.gov/galileo
14-year odyssey 14-year odyssey.
Radioisotope Thermoelectric Generators (RTG) Radioisotope Thermoelectric Generators (RTG)
http://www2.jpl.nasa.gov/galileo/messenger/oldmess/RTGs.html http://www2.jpl.nasa.gov/galileo/messenger/oldmess/RTGs.html
Description of power units in the spacecraft Galileo Description of power units in the spacecraft Galileo.
http://www.nasa.gov/cassini http://www.nasa.gov/cassini
Details on spacecraft and voyage Details on spacecraft and voyage.
Gugliotta, 2007 Guy Gugliotta, Can We Survive On The Moon? Discover March 200732-
New Horizons Mission New Horizons Mission
http://pluto.jhuapl.edu http://pluto.jhuapl.edu
Trip to Pluto and the Kuiper Belt Trip to Pluto and the Kuiper Belt.
Rover Sojourner to Mars Rover Sojourner to Mars
http://mars.jpl.nasa.gov/MPF/mpf/rover.html http://mars.jpl.nasa.gov/MPF/mpf/rover.html
Equipped with RTGs Equipped with RTGs.
Artificial Heart Artificial Heart
http://www.fda.gov/bbs/topics/NEWS/2006/NEW01443.html http://www.fda.gov/bbs/topics/NEWS/2006/NEW01443.html
Mechanical implantable heart, approved by FDA Mechanical implantable heart, approved by FDA.
America at the Threshold, 1991 America at the Threshold Report of the Synthesis Group on America's Space Exploration Initiative 1991 NASA Arlington, VA An illustrated description of the proposed goals and plans for the space trips to the Moon and Mars
Whole Mars Catalog Whole Mars Catalog
http://www.marstoday.com http://www.marstoday.com
The Mars Society The Mars Society
http://www.marssociety.org http://www.marssociety.org
Activities, news, publications, and conventions Activities, news, publications, and conventions.
http://htx.pppl.gov/ht.html http://htx.pppl.gov/ht.html
High thrust plasma propulsion system High thrust plasma propulsion system. Research by Princeton Lab.