NERVA

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Marcus Cocceius Nerva was also the name of a Roman emperor
Diagram of the NERVA nuclear rocket engine.
Diagram of the NERVA nuclear rocket engine.

NERVA is an acronym for Nuclear Engine for Rocket Vehicle Application. The NERVA rocket engine was based on Kiwi nuclear reactor technology (the original flightless nuclear thermal rocket designs were named after the Kiwi, a flightless bird). In the early 1960s NASA planned to use NERVA to power a RIFT (Reactor-In-Flight-Test) nuclear stage to be launched in the early 1970s. The completed NERVA would be a nuclear powered upper stage for the Saturn V, which would allow the upgraded Saturn to launch interplanetary payloads. NASA's Marshall Space Flight Center had the development responsibility for the rocket stage.

From the beginning the program had a number of problems. It was very expensive. It never held much public support, owing to the growing anti-nuclear lobby in the United States in the early 1970s. There were environmental concerns and the test engines themselves never managed to produce more than 40% of their theoretical thrust, which made them far less powerful than contemporary conventional rocket engines.

Eugene F. Lally of the Jet Propulsion Laboratory/Caltech proposed Manned Mars Missions in the early 60's using the NERVA engine for upper stages to maximize payload and minimize cost. One mission design included separating the spacecraft connected by cables during the long transit to Mars and rotating two sections to simulate gravity and protect the astronauts from bone mass loss. Also a mosaic optical guidance and navigation system was positioned in the center of rotation to provide real time onboard navigation information to the astronauts. The optical system consisted of the first concept of a digital still camera. It used a mosaic array of light detectors to digitally produce photos of star backgrounds and planet approaches to assist with guidance and navigation.

Werner von Braun also proposed a Manned Mars Mission using NERVA and a spinning donut shaped spacecraft to create gravity.

The NERVA program was cancelled in 1972.

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[edit] In fiction

In Stephen Baxter's novel Voyage the Nerva project is not cancelled but goes on into the early eighties producing a test article Apollo-N in 1980. Due to rushed deadlines, poor design and a fundamental lack of understanding of the technology disaster strikes. The NERVA booster is fired successfully only once. When restart is attempted in orbit the device explodes, irradiating the ship and the astronauts. When the Apollo capsule makes an emergency return to Earth only one Astronaut remains alive and he dies of radiation poisoning 47 days later.

This event nearly derails the fictional Mars program of the book but it is rebuilt using a chemical mission mode via Venus and the expedition arrives on Mars in 1986. Apollo N becomes that timeline’s Challenger disaster, and the NERVA technology is abandoned as unsafe, probably permanently.

[edit] NERVA Rocket Stage Specifications

  • Diameter: 10.55 m
  • Length: 43.69 m
  • Weight empty: 34,019 kg
  • Weight full: 178,321 kg
  • Thrust (vacuum): 867 kN (194,919 lbf)
  • ISP (vacuum): 825 s (8.09 kN·s/kg)
  • ISP (sea level): 380 s (3.73 kN·s/kg)
  • Burn Time: 1,200 s
  • Propellants: Nuclear/LH2
  • Engines: 1 Nerva-2

[edit] See also

[edit] External links

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