SNAP-10A (Systems for Nuclear Auxiliary Power, aka Snapshot for Space Nuclear Auxiliary Power Shot, also known as OPS 4682) was a US experimental

nuclear power Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced b ...

ed satellite launched into space in 1965 as part of the SNAPSHOT program.SNAPSHOT
NASA Glenn Research Center, March 20, 2007. Retrieved 3 April 2019.
Gunther's Space Page. Retrieved 3 April 2019. The test marked both the world's first operation of a nuclear reactor in orbit,History of US Astronuclear Reactors part 1: SNAP-2 and 10A
, ''Beyond NERVA'', April 3, 2019. Retrieved 3 April 2019. and the first operation of an

ion thruster An ion thruster, ion drive, or ion engine is a form of electric propulsion used for spacecraft propulsion. It creates thrust by accelerating ions using electricity. An ion thruster ionizes a neutral gas by extracting some electrons out of a ...

system in orbit. It is the only

fission reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from ...

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 United States Atomic Energy Commission (AEC) was an agency of the United States government established after World War II by U.S. Congress to foster and control the peacetime development of atomic science and technology. President ...

History

The

Systems for Nuclear Auxiliary Power 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. Odd-numbered SNAPs: radioisotope thermoelectric generators ...

(SNAP) program developed as a result of Project Feedback, a Rand Corporation study of reconnaissance satellites completed in 1954. As some of the proposed satellites had high power demands, some as high as a few kilowatts, the U.S. Atomic Energy Commission (AEC) requested a series of nuclear power-plant studies from industry in 1951. Completed in 1952, these studies determined that nuclear power plants were technically feasible for use on satellites. In 1955, the AEC began two parallel SNAP nuclear power projects. One, contracted with The Martin Company, used radio-isotopic decay as the power source for its generators. These plants were given odd-numbered SNAP designations beginning with SNAP-1. The other project used nuclear reactors to generate energy, and was developed by the Atomics International Division of

North American Aviation North American Aviation (NAA) was a major American aerospace manufacturer that designed and built several notable aircraft and spacecraft. Its products included: the T-6 Texan trainer, the P-51 Mustang fighter, the B-25 Mitchell bomber, the F ...

. Their systems were given even-numbered SNAP designations, the first being SNAP-2. SNAP-10A was the first Atomics International, nuclear-reactor power system built for use in space. Evolved from the SNAP-10 300 watt design, SNAP-10A fulfilled a 1961 Department of Defense requirement for a 500 watt system. Most of the systems development and reactor testing was conducted at the

Santa Susana Field Laboratory The Santa Susana Field Laboratory (SSFL), formerly known as Rocketdyne, is a complex of industrial research and development facilities located on a portion of Southern California in an unincorporated area of Ventura County in the Simi Hills betw ...

, Ventura County, California using a number of specialized facilities.

Construction

The SNAP-10A has three major components – (1) a compact fission reactor that generates heat, (2) an energy converter that transforms some of the heat into electricity, and (3) a radiator that radiates away heat that cannot be used. The reactor measures 39.62 cm (15.6 in) long, 22.4 cm (8.8 in) diameter and holds 37 fuel rods containing ²³⁵U as uranium-zirconium-hydride fuel. The SNAP-10A reactor was designed for a thermal power output of 30 kW and unshielded weighs . The reactor can be identified at the top of the SNAP-10A unit. Reflectors were arranged around the outside of the reactor to provide the means to control the reactor. The reflectors were composed of a layer of beryllium, which would reflect neutrons, thus allowing the reactor to begin and maintain the fission process. The reflectors were held in place by a retaining band anchored by an

explosive bolt A pyrotechnic fastener (also called an explosive bolt, or pyro, within context) is a fastener, usually a nut or bolt, that incorporates a pyrotechnic charge that can be initiated remotely. One or more explosive charges embedded within the bolt a ...

. When the reflector was ejected from the unit, the reactor could not sustain the nuclear fission reaction and the reactor permanently shut down. The eutectic sodium-potassium (

NaK In data networking, telecommunications, and computer buses, an acknowledgment (ACK) is a signal that is passed between communicating processes, computers, or devices to signify acknowledgment, or receipt of message, as part of a communicatio ...

) alloy was used as a coolant in the SNAP-10A. The NaK was circulated through the core and thermoelectric converters by a liquid metal direct current conduction-type pump. The thermoelectric converters (identified as the long white "apron") are doped silicon germanium materials, thermally coupled, but electrically isolated from the NaK heat transfer medium. The temperature difference between the NaK on one side of the thermoelectric converter and the cold of space on the other created an electric potential and usable electricity.

SNAPSHOT mission

Launch and orbital operation

SNAP-10A was launched from

Vandenberg Air Force Base Vandenberg may refer to: * Vandenberg (surname), including a list of people with the name * USS General Harry Taylor (AP-145), USNS ''General Hoyt S. Vandenberg'' (T-AGM-10), transport ship in the United States Navy, sank as an artificial reef in K ...

by an ATLAS Agena D rocket on 3 April 1965 into a

low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...

altitude of approx. 1,300 km. It is in a slightly retrograde

polar orbit A polar orbit is one in which a satellite passes above or nearly above both poles of the body being orbited (usually a planet such as the Earth, but possibly another body such as the Moon or Sun) on each revolution. It has an inclination of about ...

— this ensured that the spent rocket stages landed in the ocean. Its nuclear electrical source, made up of thermoelectric elements, was intended to produce over 500 watts of electrical power for one year. After 43 days, an onboard

voltage regulator A voltage regulator is a system designed to automatically maintain a constant voltage. A voltage regulator may use a simple feed-forward design or may include negative feedback. It may use an electromechanical mechanism, or electronic components ...

within the spacecraft – unrelated to the SNAP reactor – failed, causing the

reactor core A nuclear reactor core is the portion of a nuclear reactor containing the nuclear fuel components where the nuclear reactions take place and the heat is generated. Typically, the fuel will be low-enriched uranium contained in thousands of indiv ...

to be shut down, after reaching a maximum output of 590 watts. After the 1965 system failure, the reactor was left in a Earth orbit for an expected duration of 4,000 years. In November 1979 the vehicle began shedding, eventually losing 50 pieces of traceable

debris Debris (, ) is rubble, wreckage, ruins, litter and discarded garbage/refuse/trash, scattered remains of something destroyed, or, as in geology, large rock fragments left by a melting glacier, etc. Depending on context, ''debris'' can refer to ...

. The reasons were unknown, but the cause could have been a collision. Although the main body remains in place, radioactive material may have been released. Later research, published in 2008 and based on

Haystack Hay is grass, legumes, or other herbaceous plants that have been cut and dried to be stored for use as animal fodder, either for large grazing animals raised as livestock, such as cattle, horses, goats, and sheep, or for smaller domesticated ...

data, suggests that there are another 60 or more pieces of debris of size <10 cm.

Ion propulsion

The SNAPSHOT test included a cesium

as a secondary payload, the first test of an

electrically powered spacecraft propulsion Spacecraft electric propulsion (or just electric propulsion) is a type of spacecraft propulsion technique that uses electrostatic or electromagnetic fields to accelerate mass to high speed and thus generate thrust to modify the velocity of a s ...

system to operate in orbit (following the

SERT-1 SERT-1 (Space Electric Rocket Test) was a NASA probe used to test electrostatic ion thruster design and was built by NASA's Lewis Research Center (now NASA Glenn). SERT-1 was the first spacecraft to utilize ion engine design. It was launched on ...

suborbital test in 1964). The ion-beam power supply was operated at 4500 V and 80 mA to produce a thrust of about 8.5 mN. The ion engine was to be operated off batteries for about one hour, and then the batteries were to be charged for approximately 15 hours using 0.1 kW of the nominal 0.5 kW SNAP system as the power supply. The ion engine operated for a period of less than 1 hour before being commanded off permanently. Analysis of flight data indicated a significant number of high-voltage breakdowns, and this apparently caused electromagnetic interference (EMI), causing attitude perturbations of the spacecraft. Ground tests indicated that the engine arcing produced conducted and radiated EMI significantly above design levels.

Safety

The SNAP reactor program necessitated a safety program and led to the inception of the Aerospace Nuclear Safety Program. The program was established to evaluate the nuclear hazards associated with the construction, launch, operation and disposal of SNAP systems and to develop designs to assure their radiological safety.

Atomics International Atomics International was a division of the North American Aviation company (later acquired by the Rockwell International company) which engaged principally in the early development of nuclear technology and nuclear reactors for both commercia ...

had primary responsibility for safety, while

Sandia National Laboratories Sandia National Laboratories (SNL), also known as Sandia, is one of three research and development laboratories of the United States Department of Energy's National Nuclear Security Administration (NNSA). Headquartered in Kirtland Air Force Ba ...

was responsible for the Aerospace Safety Independent Review and conducted many of the safety tests. Before launch was permitted, proof had to be obtained that under all circumstances the launch of the reactor would not pose a serious threat. A variety of tests were successfully completed and several videos of the development and tests are available for viewing. The

Idaho National Laboratory Idaho National Laboratory (INL) is one of the national laboratories of the United States Department of Energy and is managed by the Battelle Energy Alliance. While the laboratory does other research, historically it has been involved with nu ...

conducted three destructive tests of SNAP nuclear reactors at Test Area North prior to the launch of SNAP-10A. Chapter 17: Science in the Desert. The SNAPTRAN-3 destructive experiment, on 1 April 1964, simulated a rocket crash into the ocean, purposely sending

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consid ...

debris across the Idaho desert. The testing and development involving radioactive materials caused environmental contamination at the former Atomics International Santa Susana Field Laboratory (SSFL) facilities. The

United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United Stat ...

is responsible for the identification and cleanup of the radioactive contamination. (The SSFL was also used for the unrelated testing and development of rocket engines by

Rocketdyne Rocketdyne was an American rocket engine design and production company headquartered in Canoga Park, California, Canoga Park, in the western San Fernando Valley of suburban Los Angeles, California, Los Angeles, in southern California. The Rocke ...

primarily for

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

.) The DOE website supporting the site cleanup details the historical development of nuclear energy at SSFL including additional SNAP testing and development information.

Related work and follow-on programs

Atomics International also developed and tested other compact nuclear reactors including the SNAP Experimental Reactor (SER), SNAP-2, SNAP-8 Developmental Reactor (SNAP8-DR) and SNAP-8 Experimental Reactor (SNAP-8ER) units at the Santa Susana Field Laboratory (see

article). Atomics International also built and operated the

Sodium Reactor Experiment The Sodium Reactor Experiment was a pioneering nuclear power plant built by Atomics International at the Santa Susana Field Laboratory near Simi Valley, California. The reactor operated from 1957 to 1964. On December 20, 1951, the first Experimen ...

, the first U.S. nuclear power plant to supply electricity to a public power system. , more than 30 small fission power system nuclear reactors have been sent into space in Soviet

RORSAT Upravlyaemy Sputnik Aktivnyy (russian: Управляемый Спутник Активный for Controlled Active Satellite), or US-A, also known in the west as Radar Ocean Reconnaissance Satellite or RORSAT (GRAU index 17F16K), was a series of ...

satellites; also, over 40

radioisotope thermoelectric generator A radioisotope thermoelectric generator (RTG, RITEG), 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 radioacti ...

s have been used globally (principally US and USSR) on space missions.

References

External links

International Designator The International Designator, also known as COSPAR ID, is an international identifier assigned to artificial objects in space. It consists of the launch year, a three-digit incrementing launch number of that year and up to a three-letter code repr ...

1965-027A

Snapshot – Orbit
* {{DEFAULTSORT:Snap-10A Nuclear power in space Nuclear power reactor types Atomics International Satellites orbiting Earth Derelict satellites orbiting Earth Spacecraft launched in 1965 United States Atomic Energy Commission ru:Ядерные реакторы на космических аппаратах#SNAP