S.1 Spacecraft Propulsion Systems Chapter 1: Introduction to ...

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New Approaches in Advanced Propulsion: Nuclear Rockets
Nuclear-Thermal Propulsion
(Courtesy of SNECMA)
Concept: There are two main different categories of
nuclear technology for space power and propulsion:
- radioisotope thermoelectric generators (RTG)
and close-cycle (e.g. Sterling technology) for
nuclear electric power, NEP, to power electric
propulsion
- open-cycle nuclear thermal reactors, NTR, which
heat e.g. liquid hydrogen propellant directly to
produce rocket thrust
NEP: Flight heritage of RTG’s with power level < 10 kWe
while future NEP’s aim at 10 kWe to MWe’s for electric
propulsion: ve = 20 000 m/s to 100 000 m/s (FEEP)
NTR: liquid hydrogen propellant absorbs heat from the
core of a fission reactor, before expanding through a
nozzle: ve = 8000 m/s to 9000 m/s, F = 20kN to 70 kN
Extensive research performed into nuclear-thermal
rockets in U.S. in 1960 as part of the NERVA program.
Status: Environmental and political concern about save
ground test and launch of fueled reactor has reduced
research in NEP and NTR technology.