Influence of Wave Rotor Thermal Decomposition on Alternative Nuclear Rocket Propellant Performance †.
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| Title: | Influence of Wave Rotor Thermal Decomposition on Alternative Nuclear Rocket Propellant Performance †. |
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| Authors: | Osborne, Garrison1 (AUTHOR), Gosse, Ryan1 (AUTHOR) rgosse@eng.famu.fsu.edu |
| Source: | Energies (19961073). Sep2026, Vol. 19 Issue 17, p4047. 34p. |
| Subject Terms: | *Propellants, *Space flight propulsion systems, *Brayton cycle, *Ammonia gas, *Thermolysis, *Turbomachines, *Hydrogen as fuel |
| Company/Entity: | United States. National Aeronautics & Space Administration |
| Abstract: | The proposed wave rotor enhanced nuclear propulsion (WREN) system is a potential technology candidate for timely and efficient manned missions to Mars. Using Hydrogen (H2), conventional nuclear thermal propulsion (NTP) can attain an I s p of 800–1000 s as it reaches the thermal limits of its solid core reactor material. A four-port wave rotor turbomachine coupled to a closed Brayton cycle can go beyond this limitation, further heating the H2 to attain an I s p of 1400–1500 s. Despite this improvement, liquid H2 currently poses significant storage problems that limit transit performance. This work explores the use of denser propellants that use the full launch mass of a rocket compared to liquid H2. This includes ammonia (NH3), water (H2O), and methane (CH4). Using NERVA-class NTP technology, the I s p of these alternatives is comparable to chemical rockets. The WREN fluid and subsystem cycle was modeled using an object-oriented hardware sizing program equipped with NASA CEA thermochemistry and coupled to an optimization framework. Given a specific set of constraints, a 25-klbf (111.2 kN) class WREN engine produced I s p values of 663.6 s for NH3, 469.6 s for H2O, and 360.1 s for CH4. NH3 and H2O achieved density-impulse values comparable to vacuum-rated hydrolox engines, making them competitive with in-space chemical rockets on a volumetric basis. NH3 provided the strongest overall balance of I s p , storage density, and Δ V favorability compared with H2 NTP, whereas H2O produced a small radiator that enabled a higher thrust-to-weight regime. At a representative Δ V of 12 km/s, the propellant savings of NH3 WREN reduced the combined propellant-tank and radiator launch elements from 27 launches for conventional NH3 NTP to 13 launches, of which only nine were propellant-tank launches. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
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| Abstract: | The proposed wave rotor enhanced nuclear propulsion (WREN) system is a potential technology candidate for timely and efficient manned missions to Mars. Using Hydrogen (H2), conventional nuclear thermal propulsion (NTP) can attain an I s p of 800–1000 s as it reaches the thermal limits of its solid core reactor material. A four-port wave rotor turbomachine coupled to a closed Brayton cycle can go beyond this limitation, further heating the H2 to attain an I s p of 1400–1500 s. Despite this improvement, liquid H2 currently poses significant storage problems that limit transit performance. This work explores the use of denser propellants that use the full launch mass of a rocket compared to liquid H2. This includes ammonia (NH3), water (H2O), and methane (CH4). Using NERVA-class NTP technology, the I s p of these alternatives is comparable to chemical rockets. The WREN fluid and subsystem cycle was modeled using an object-oriented hardware sizing program equipped with NASA CEA thermochemistry and coupled to an optimization framework. Given a specific set of constraints, a 25-klbf (111.2 kN) class WREN engine produced I s p values of 663.6 s for NH3, 469.6 s for H2O, and 360.1 s for CH4. NH3 and H2O achieved density-impulse values comparable to vacuum-rated hydrolox engines, making them competitive with in-space chemical rockets on a volumetric basis. NH3 provided the strongest overall balance of I s p , storage density, and Δ V favorability compared with H2 NTP, whereas H2O produced a small radiator that enabled a higher thrust-to-weight regime. At a representative Δ V of 12 km/s, the propellant savings of NH3 WREN reduced the combined propellant-tank and radiator launch elements from 27 launches for conventional NH3 NTP to 13 launches, of which only nine were propellant-tank launches. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 19961073 |
| DOI: | 10.3390/en19174047 |
