A nuclear thermal rocket (NTR) is a type of thermal rocket where the heat from a nuclear reaction, often nuclear fission, replaces the chemical energy of the propellants in a chemical rocket. In an NTR, a working fluid, usually liquid hydrogen, is heated to a high temperature in a nuclear reactor and then expands through a rocket nozzle to create thrust. The external nuclear heat source theoretically allows a higher effective exhaust velocity and is expected to double or triple payload capacity compared to chemical propellants that store energy internally.
A nuclear electric rocket is a type of spacecraft propulsion system where thermal energy from a nuclear reactor is converted to electrical energy, which is used to drive an ion thruster or other electrical spacecraft propulsion technology. The nuclear electric rocket terminology is slightly inconsistent, as technically the "rocket" part of the propulsion system is non-nuclear and could also be driven by solar panels. This is in contrast with a nuclear thermal rocket, which directly uses reactor heat to add energy to a working fluid, which is then expelled out of a rocket nozzle.
Nuclear pulse propulsion or external pulsed plasma propulsion is a hypothetical method of spacecraft propulsion that uses nuclear explosions for thrust. It originated as Project Orion with support from DARPA, after a suggestion by Stanislaw Ulam in 1947. Newer designs using inertial confinement fusion have been the baseline for most later designs, including Project Daedalus and Project Longshot.
A radioisotope thermoelectric generator, sometimes referred to as a radioisotope power system (RPS), is a type of nuclear battery that uses an array of thermocouples to convert the heat released by the decay of a suitable radioactive material into electricity by the Seebeck effect. This type of generator has no moving parts.
The Jupiter Icy Moons Orbiter (JIMO) was a proposed NASA spacecraft designed to explore the icy moons of Jupiter. The main target was Europa, where an ocean of liquid water may harbor alien life. Ganymede and Callisto, which are now thought to have liquid, salty oceans beneath their icy surfaces, were also targets of interest for the probe.
Nuclear propulsion includes a wide variety of propulsion methods that use some form of nuclear reaction as their primary power source. The idea of using nuclear material for propulsion dates back to the beginning of the 20th century. In 1903 it was hypothesized that radioactive material, radium, might be a suitable fuel for engines to propel cars, planes, and boats. H. G. Wells picked up this idea in his 1914 fiction work The World Set Free.
The Nuclear Engine for Rocket Vehicle Application (NERVA) was a nuclear thermal rocket engine development program that ran for roughly two decades. Its principal objective was to "establish a technology base for nuclear rocket engine systems to be utilized in the design and development of propulsion systems for space mission application". NERVA was a joint effort of the Atomic Energy Commission (AEC) and the National Aeronautics and Space Administration (NASA), and was managed by the Space Nuclear Propulsion Office (SNPO) until the program ended in January 1973. SNPO was led by NASA's Harold Finger and AEC's Milton Klein.
A radioisotope rocket or radioisotope thermal rocket is a type of thermal rocket engine that uses the heat generated by the decay of radioactive elements to heat a working fluid, which is then exhausted through a rocket nozzle to produce thrust. They are similar in nature to nuclear thermal rockets such as NERVA, but are considerably simpler and often have no moving parts. Alternatively, radioisotopes may be used in a radioisotope electric rocket, in which energy from nuclear decay is used to generate the electricity used to power an electric propulsion system.
An interstellar probe is a space probe that has left—or is expected to leave—the Solar System and enter interstellar space, which is typically defined as the region beyond the heliopause. It also refers to probes capable of reaching other star systems.
SNAP-10A was a US experimental nuclear powered satellite launched into space in 1965 as part of the SNAPSHOT program. The test marked both the world's first operation of a nuclear reactor in orbit, and the first operation of an ion thruster system in orbit. It is the only fission reactor power system launched into space by the United States. The reactor stopped working after just 43 days due to a non-nuclear electrical component failure. The Systems Nuclear Auxiliary Power Program reactor was specifically developed for satellite use in the 1950s and early 1960s under the supervision of the U.S. Atomic Energy Commission.
The Westinghouse Astronuclear Laboratory (WANL) was a division of Westinghouse Electric Corporation. Established in 1959 to develop nuclear space propulsion technologies for the government, the lab was located, for most of its history, in the paradoxically small town of "Large" along Pa. Rte 51, about 13 miles (21 km) south of Pittsburgh in Allegheny County, Pennsylvania, USA. The site is not far from the Bettis Atomic Power Laboratory in West Mifflin, which Westinghouse operated during the same time and later.
The Systems Nuclear Auxiliary POWER (SNAP) program was a program of experimental radioisotope thermoelectric generators (RTGs) and space nuclear reactors flown during the 1960s by NASA.
Westinghouse Advanced Energy Systems Division (AESD) was a research and development facility for nonconventional renewable energy systems, in the small town of Large in Allegheny County, Pennsylvania [USA]. The site is on the east side of Pa. Rte. 51, about 13 miles (21 km) south of Pittsburgh. Formerly the site of the Westinghouse Astronuclear Laboratory (WANL), Westinghouse Electric Corporation changed the name of the facility, along with its charter, in 1977.
The multi-mission radioisotope thermoelectric generator (MMRTG) is a type of radioisotope thermoelectric generator (RTG) developed for NASA space missions such as the Mars Science Laboratory (MSL), under the jurisdiction of the United States Department of Energy's Office of Space and Defense Power Systems within the Office of Nuclear Energy. The MMRTG was developed by an industry team of Aerojet Rocketdyne and Teledyne Energy Systems.
Project Rover was a United States project to develop a nuclear-thermal rocket that ran from 1955 to 1973 at the Los Alamos Scientific Laboratory (LASL). It began as a United States Air Force project to develop a nuclear-powered upper stage for an intercontinental ballistic missile (ICBM). The project was transferred to NASA in 1958 after the Sputnik crisis triggered the Space Race. It was managed by the Space Nuclear Propulsion Office (SNPO), a joint agency of the Atomic Energy Commission (AEC), and NASA. Project Rover became part of NASA's Nuclear Engine for Rocket Vehicle Application (NERVA) project and henceforth dealt with the research into nuclear rocket reactor design, while NERVA involved the overall development and deployment of nuclear rocket engines, and the planning for space missions.
The United States Space Nuclear Propulsion Office (SNPO) was created in 1961 in response to NASA Marshall Space Flight Center's desire to explore the use of nuclear thermal rockets created by Project Rover in NASA space exploration activities. Because Project Rover fell under the aegis of the Atomic Energy Commission, a way had to be found for NASA and the AEC to share a large, expensive, classified program; specifically, Los Alamos was developing technology for NASA to use.
A thermal rocket is a rocket engine that uses a propellant that is externally heated before being passed through a nozzle to produce thrust, as opposed to being internally heated by a redox (combustion) reaction as in a chemical rocket.
Harold Benjamin Finger is an American aeronautical nuclear engineer and the former head of the United States nuclear rocket program. He helped establish and lead the Space Nuclear Propulsion Office, a liaison organization between NASA and the Atomic Energy Commission to coordinate efforts to create a nuclear thermal rocket.
Nuclear power in space is the use of nuclear power in outer space, typically either small fission systems or radioactive decay for electricity or heat. Another use is for scientific observation, as in a Mössbauer spectrometer. The most common type is a radioisotope thermoelectric generator, which has been used on many space probes and on crewed lunar missions. Small fission reactors for Earth observation satellites, such as the TOPAZ nuclear reactor, have also been flown. A radioisotope heater unit is powered by radioactive decay and can keep components from becoming too cold to function, potentially over a span of decades.
Galileo was an American robotic space probe that studied the planet Jupiter and its moons, as well as the asteroids Gaspra and Ida. Named after the Italian astronomer Galileo Galilei, it consisted of an orbiter and an entry probe. It was delivered into Earth orbit on October 18, 1989, by Space ShuttleAtlantis, during STS-34. Galileo arrived at Jupiter on December 7, 1995, after gravitational assist flybys of Venus and Earth, and became the first spacecraft to orbit an outer planet.
