NERVA - AbsoluteAstronomy.com

NERVA is an acronym for Nuclear Engine for Rocket Vehicle Application, a joint program of the U.S. Atomic Energy Commission

United States Atomic Energy Commission

The United States Atomic Energy Commission was an agency of the United States government established after World War II by Congress to foster and control the peace time development of atomic science and technology. President Harry S...

and NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

managed by the Space Nuclear Propulsion Office

Space Nuclear Propulsion Office

The United States Space Nuclear Propulsion Office 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...

(SNPO) until both the program and the office ended at the end of 1972.

NERVA demonstrated that nuclear thermal rocket

Nuclear thermal rocket

In a nuclear thermal rocket 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. In this kind of thermal rocket, the nuclear reactor's energy replaces the chemical energy of the propellant's...

engines were a feasible and reliable tool for space exploration, and at the end of 1968 SNPO certified that the latest NERVA engine, the NRX/XE, met the requirements for a manned Mars mission. Although NERVA engines were built and tested as much as possible with flight-certified components and the engine was deemed ready for integration into a spacecraft, much of the U.S. space program was cancelled by the Nixon Administration before a manned visit to Mars could take place.

NERVA was considered by the AEC, SNPO and NASA to be a highly successful program; it met or exceeded its program goals. 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". Virtually all space mission plans that use nuclear thermal rockets use derivative designs from the NERVA NRX or Pewee.

Project Rover

Los Alamos Scientific Laboratory began researching nuclear rockets in 1952, accelerating into Project Rover

Project Rover

Project Rover was an American project to develop a nuclear thermal rocket. The program ran at the Los Alamos Scientific Laboratory from 1955 through 1972 and involved the Atomic Energy Commission, and NASA. The project was managed by the Space Nuclear Propulsion Office.Nuclear reactors for the...

in 1955 when the deputy director of Lawrence Livermore National Laboratory

Lawrence Livermore National Laboratory

The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...

thought of a way to shrink reactor weights considerably. By 1961, after unexpectedly fast-paced progress on the part of Project Rover

Project Rover

, NASA's Marshall Space Flight Center

Marshall Space Flight Center

The George C. Marshall Space Flight Center is the U.S. government's civilian rocketry and spacecraft propulsion research center. The largest center of NASA, MSFC's first mission was developing the Saturn launch vehicles for the Apollo moon program...

began to use nuclear thermal rockets in their mission plans. Marshall planned to use a nuclear-powered rocket from Los Alamos to power a RIFT (Reactor-In-Flight-Test) nuclear stage to be launched as early as 1964, and the need for planning and oversight led to the formation of the Space Nuclear Propulsion Office

Space Nuclear Propulsion Office

. SNPO was formed so that the AEC and NASA could work together, and H. B. "Harry" Finger

Harold Finger

Harold Benjamin Finger is an 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 Department of Energy to coordinate efforts to create a nuclear...

was selected as its first director. Finger made a decision to delay RIFT, and he defined strict objectives for nuclear rocket engines to achieve before RIFT would be allowed.

NERVA engine development

Finger then immediately selected Aerojet

Aerojet

Aerojet is an American rocket and missile propulsion manufacturer based primarily in Rancho Cordova, California with divisions in Redmond, Washington, Orange, Gainesville and Camden, Arkansas. Aerojet is owned by GenCorp. They are the only US propulsion company that provides both solid rocket...

and Westinghouse

Westinghouse Astronuclear Laboratory

The Westinghouse Astronuclear Laboratory was a division of Westinghouse Electric Corporation. Established in the late 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,...

to develop the NERVA engine. SNPO would depend on what was then known as Los Alamos Scientific Laboratory to supply technology for NERVA rocket engines as part of Project Rover

Project Rover

. SNPO chose the original 825 second 75,000 pound-thrust KIWI-B4 nuclear thermal rocket design, named after the Kiwi

Kiwi

Kiwi are flightless birds endemic to New Zealand, in the genus Apteryx and family Apterygidae.At around the size of a domestic chicken, kiwi are by far the smallest living ratites and lay the largest egg in relation to their body size of any species of bird in the world...

, a flightless bird native to New Zealand, as the baseline for the 52-inch (22 feet from thrust structure to nozzle bottom) NERVA NRX (Nuclear Rocket Experimental). Phase 2 of Project Rover became called Phoebus, and Phase 3 was known as Pewee, demonstrating much higher power (4000 MW), power density and long-lived fuels, but these programs did not make their way to NERVA. Working NERVA designs (termed NERVA NRX) were based on KIWI; by the time Pewee started testing the Apollo program had largely been defunded by the Nixon administration. Plans to send humans to the Moon and Mars had been indefinitely delayed.

Almost all of the NERVA research, design and fabrication was done at Los Alamos Scientific Laboratory. Testing was done at a large installation specially built by SNPO on the Nevada Test Site

Nevada Test Site

The Nevada National Security Site , previously the Nevada Test Site , is a United States Department of Energy reservation located in southeastern Nye County, Nevada, about northwest of the city of Las Vegas...

. Although Los Alamos tested several KIWI and Phoebus engines during the 1960's, testing of NASA's NERVA NRX/EST (Engine System Test) contractor engine didn't begin until February 1966. The objectives were:

Demonstrate the feasibility of starting and restarting the engine without an external power source.
Evaluate the control system characteristics (stability and control mode) during startup, shutdown, cooldown and restart for a variety of initial conditions.
Investigate the system stability over a broad operating range.
Investigate the endurance capability of the engine components, especially the reactor, during transient and steady state operation with multiple restarts.

All test objectives were successfully accomplished, and the first NERVA NRX operated for nearly 2 hours, including 28 minutes at full power. It exceeded the operating time of previous KIWI reactors by nearly a factor of two.

NERVA XE

The second NERVA engine, the NERVA XE, was designed to come as close as possible to a complete flight system, even to the point of using a flight-design turbopump. Components that would not affect system performance were allowed to be selected from what was available at Jackass Flats, Nevada to save money and time, and a radiation shield was added to protect external components. The engine was reoriented to fire downward into a reduced-pressure compartment to partially simulate firing in a vacuum.

The NERVA NRX/EST engine test objectives now included:

Demonstrating engine system operational feasibility
Showing that no enabling technology issues remained as a barrier to flight engine development.
Demonstrating completely automatic engine startup.

The objectives also included testing the use of the new facility at Jackass Flats for flight engine qualification and acceptance. Total run time was 115 minutes, including 28 starts. NASA and SNPO felt that the test "confirmed that a nuclear rocket engine was suitable for space flight application and was able to operate at a specific impulse twice that of chemical rocket system [sic]." The engine was deemed adequate for Mars missions being planned by NASA. The facility was also deemed adequate for flight qualification and acceptance of rocket engines from the two contractors.

Loss of political support and cancellation

The Rover/NERVA program accumulated 17 hours of operating time with 6 hours above 2000 K. Although the engine, turbine and liquid hydrogen tank were never physically assembled together, the NERVA was deemed ready to design into a working vehicle by NASA, creating a small political crisis in Congress because of the danger a Mars exploration program presented to the national budget. Clinton P. Anderson, the New Mexico senator who had protected the program, had become severely ill. Lyndon B. Johnson, another powerful advocate of human space exploration, had decided not to run for a second term and was considerably weakened. NASA program funding was somewhat reduced by Congress for the 1969 budget, and the incoming Nixon administration reduced it still further for 1970, shutting down the Saturn rocket production line and cancelling Apollo missions after Apollo 17. Without the Saturn S-N rocket to carry the NERVA to orbit, Los Alamos continued the Rover Program for a few more years with Pewee and the Nuclear Furnace, but it was disbanded by 1972.

The most serious injury during testing was a hydrogen explosion in which two employees sustained foot and ear drum injuries. At one point in 1965 the liquid hydrogen storage at Test Cell #2 during a Los Alamos Scientific Laboratory Test was accidentally allowed to run dry; the core overheated and ejected on to the floor of the Nevada desert. Test Site personnel waited 3 weeks and then walked out and collected the pieces without mishap. The nuclear waste from the damaged core was spread across the desert and was collected by an Army group as a decontamination exercise.

NERVA in the space program

NASA plans for NERVA included a visit to Mars by 1978 and a permanent lunar base by 1981. NERVA rockets would be used for nuclear "tugs" designed to take payloads from Low Earth Orbit to larger orbits as a component of the later-named Space Transportation System

Space Transportation System

The Space Transportation System is another name for the NASA Space Shuttle and Space Shuttle program. However, the name originates from, and can describe a more elaborate set of spacefaring hardware in the 1970s, although this meaning is obscure...

, resupply several space stations in various orbits around the Earth and Moon, and support a permanent lunar base. The NERVA rocket would also be a nuclear-powered upper stage for the Saturn rocket (the Saturn S-N), which would allow the upgraded Saturn to launch much larger payloads of up to 340,000 pounds to Low Earth Orbit.

NERVA rockets had progressed rapidly to the point where they could run for hours, limited in run time by the size of the liquid hydrogen propellant tanks at the Jackass Flats test site. They also climbed in power density. The larger NERVA I rocket gradually gave way to the smaller NERVA II rocket in mission plans as efficiency increased and thrust-to-weight ratios grew, and the KIWI gradually gave way at Los Alamos to the smaller Pewee and Pewee 2 as funding was cut to lower and lower levels by Congress and the Nixon administration.

The RIFT vehicle consisted of a Saturn S-IC first stage, an SII stage and an S-N (Saturn-Nuclear) third stage. The Space Nuclear Propulsion Office planned to build ten RIFT vehicles, six for ground tests and four for flight tests, but RIFT was delayed after 1966 as NERVA became a political proxy in the debate over a Mars mission. The nuclear Saturn C-5 would carry two to three times more payload into space than the chemical version, enough to easily loft 340,000 pound space stations and replenish orbital propellant depots. Wernher von Braun

Wernher von Braun

Wernher Magnus Maximilian, Freiherr von Braun was a German rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and in the United States after that.A former member of the Nazi party,...

also proposed a manned Mars mission using NERVA and a spinning donut-shaped spacecraft to simulate gravity. Many of the NASA plans for Mars in the 1960s and early 1970s used the NERVA rocket specifically, see list of manned Mars mission plans in the 20th century.

The Mars mission became NERVA's downfall. Members of Congress in both political parties judged that a manned mission to Mars would be a tacit commitment for the United States to decades more of the expensive Space Race

Space Race

The Space Race was a mid-to-late 20th century competition between the Soviet Union and the United States for supremacy in space exploration. Between 1957 and 1975, Cold War rivalry between the two nations focused on attaining firsts in space exploration, which were seen as necessary for national...

. Manned Mars missions were enabled by nuclear rockets; therefore, if NERVA could be discontinued the Space Race might wind down and the budget would be saved. Each year the RIFT was delayed and the goals for NERVA were set higher . Ultimately, RIFT was never authorized, and although NERVA had many successful tests and powerful Congressional backing, it never left the ground.

In fiction

In 1975 Voyager One was a fictional spacecraft that made a single appearance in the Space: 1999
Voyager One (Space: 1999)
Voyager One was a fictional spacecraft that made a single appearance in the Space: 1999 episode "Voyager's Return". Although the name is very similar, it does not refer to the Voyager 1 craft that was launched 5 September 1977 by NASA even though it did have a similar mission.-Mission...

episode "Voyager's Return". (Although the name is similar, it does not refer to the Voyager 1 craft that was launched by NASA 5 September 1977.) Its revolutionary propulsion system was known as 'the Queller Drive', an atomic engine 'used for going across space at incredible speed' by generating a stream of fast neutrons to push the craft past the speed of light.
In the 1979 novel Encounter Three, by Martin Caidin
Martin Caidin
Martin Caidin was an American author and an authority on aeronautics and aviation.Caidin wrote more than 50 books, including Samurai!, Black Thursday, Thunderbolt!, Fork-Tailed Devil: The P-38, Zero!, The Ragged, Rugged Warriors, A Torch to the Enemy and many other works of military history...

, the NERVA program is briefly discussed. It is described as "pushing more thrust through a smaller hole", and is dismissed as useless in the long-term.
In the 1985 film Lifeforce
Lifeforce (film)
Lifeforce is a 1985 science fiction film directed by Tobe Hooper from a screenplay by Dan O'Bannon and Don Jakoby, from the novel The Space Vampires, published in 1976, by Colin Wilson.-Plot:...

, the NERVA is the propulsion for the fictional space shuttle Churchill.
In Stephen Baxter
Stephen Baxter
Stephen Baxter is a prolific British hard science fiction author. He has degrees in mathematics and engineering.- Writing style :...

’s 1996 alternate timeline novel Voyage the NERVA project is not canceled but development goes on throughout the 70s producing a test article Apollo-N in 1980. A disaster occurs, the NERVA technology is abandoned as unsafe, and a mission to Mars is launched using chemical rocket engines with a slingshot gravity assist
Gravitational slingshot
In orbital mechanics and aerospace engineering, a gravitational slingshot, gravity assist maneuver, or swing-by is the use of the relative movement and gravity of a planet or other celestial body to alter the path and speed of a spacecraft, typically in order to save propellant, time, and expense...

via Venus allowing an expedition to arrive on Mars in 1986.
In Chris Berman's 2008 novel, The Hive, the discovery of an alien device between the orbits of Jupiter and Saturn in the year 2019 creates an emergency situation. This leads to a crash program with Russia and the United States partnering to re-engine a partly complete manned Mars spacecraft with a NERVA rocket motor to send a team to inspect the device.

NERVA rocket stage specifications

Diameter: 10.55 metres (34.6 ft)
Length: 43.69 metres (143.3 ft)
Mass empty: 34019 kilograms (74,999.1 lb)
Mass full: 178321 kilograms (393,130.5 lb)
Thrust (vacuum): 333.6 kN (75,000 lbf)
ISP (vacuum): 850 s (8.09 kN·s/kg)
ISP (sea level): 380 s (3.73 kN·s/kg)
Burn Time: 1,200 s
Propellants: LH₂
Engines: 1 Nerva-2

External links

NASA's Nuclear Frontier The Plum Brook Reactor Facility - 188 page monograph
NERVA in David Darling
David Darling (astronomer)
David Darling is an English astronomer and full-time freelance science writer. Darling has published numerous popular science works, including Life Everywhere: The Maverick Science of Astrobiology in 2001...

's Internet Encyclopedia of Science
Nerva entry at Encyclopedia Astronautica
Encyclopedia Astronautica
The Encyclopedia Astronautica is a reference web site on space travel. A comprehensive catalog of vehicles, technology, astronauts, and flights, it includes information from most countries that have had an active rocket research program, from Robert Goddard to the NASA Space shuttle to the Soviet...
Spacecraft: Project Nerva

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Project Rover

NERVA engine development

NERVA XE

Loss of political support and cancellation

NERVA in the space program

In fiction

NERVA rocket stage specifications

See also

External links