A 25,000-lbf Thrust Engine Options Based on the Small Nuclear Rocket Engine Design

Schnitzler, Bruce G.; Borowski, Stanley K.; Fittje, James E.

doi:10.2514/6.2009-5239

Cited by 20 publications

(11 citation statements)

References 3 publications

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“…Results from neutronic analyses of the reactor core can then be utilized to provide energy deposition rates as input to integrated thermal-fluid-structural analyses of the reactor core and engine system components. Once acceptable neutronic and thermal performance is achieved, overall engine system performance can be evaluated 12 .…”

Section: Analysis Methodologymentioning

confidence: 99%

Cycle Analysis of a 200MW Class CERMET Based NTR Engine

Fittje¹,

Schnitzler²

2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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Nuclear rocket engines utilizing W-UO2 ceramic-metal (cermet) fuel are analyzed. A highly detailed Monte Carlo Neutron-Photon (MCNP) model of the reactor core is developed and exercised to determine the energy deposited in the various engine components via decelerating fission products and scattered neutrons and photons. These results are then used by the Nuclear Engine System Simulation (NESS) code to determine engine performance characteristics, determine thermodynamic state points throughout the cycle, and estimate engine mass. These engines are expander cycle based designs and utilize no tie-tubes to extract thermal energy from the reactor to drive the turbo-machinery.

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Section: Analysis Methodologymentioning

confidence: 99%

Cycle Analysis of a 200MW Class CERMET Based NTR Engine

Fittje¹,

Schnitzler²

2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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“…Engine Design, Analysis and Modeling is aimed at developing conceptual designs for small (~7.5 klb f ) demonstration engines and higher thrust-class (~25 klb f ) engines utilizing the candidate fuels discussed above. Stateof-the-art numerical models are being used to determine reactor core criticality, detailed energy deposition and control rod worth within the reactor subsystem [25,27,35], provide thermal, fluid and stress analysis of reactor fuel elements and core components [36,37], and predict engine operating characteristics and overall mass [38,39]; Task 4. Demonstration of Affordable Ground Testing is focused on maturing equipment requirements and cost estimates for a "proof-of-concept" validation test of the SAFE (Subsurface Active Filtration of Exhaust) [40,41] concept (also known as the "bore-hole" option) at the Nevada Test Site (NTS).…”

Section: Task 1 Mission Analysis Engine/stage System Characterizatimentioning

confidence: 99%

“…Also, the same hexagonal cross-section for the FE and TT elements can be maintained across a range of different thrust levels although shorter length elements are likely for lower thrust engines. Additional analysis by Schnitzler [25,27,28] has shown that the SNRE design can be scaled down to even smaller thrust levels (~7.5 klb f ) or up to the 25 klb f Pewee-class engine used in Mars DRA 5.0.…”

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confidence: 99%

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The Nuclear Thermal Propulsion Stage (NTPS): A Key Space Asset for Human Exploration and Commercial Missions to the Moon

Borowski

McCurdy²,

Burke

2013

AIAA SPACE 2013 Conference and Exposition

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The nuclear thermal rocket (NTR) has frequently been discussed as a key space asset that can bridge the gap between a sustained human presence on the Moon and the eventual human exploration of Mars. Recently, a human mission to a near Earth asteroid (NEA) has also been included as a "deep space precursor" to an orbital mission of Mars before a landing is attempted. In his "post-Apollo" Integrated Space Program Plan (1970 -1990), Wernher von Braun, proposed a reusable NTPS to deliver cargo and crew to the Moon to establish a lunar base initially before sending human missions to Mars. The NTR was selected because it was a proven technology capable of generating both high thrust and high specific impulse (I sp ~900 s) -twice that of today's best chemical rockets. During the Rover and NERVA programs, twenty rocket reactors were designed, built and successfully ground tested. These tests demonstrated the (1) thrust levels; (2) high fuel temperatures; (3) sustained operation; (4) accumulated lifetime; and (5) restart capability needed for an affordable in-space transportation system. In NASA's Mars Design Reference Architecture (DRA) 5.0 study, the "Copernicus" crewed NTR Mars transfer vehicle used three 25 klb f "Pewee" engines -the smallest and highest performing engine tested in the Rover program. Smaller lunar transfer vehicles -consisting of a NTPS with three ~16.7 klb f "SNRE-class" engines, an in-line propellant tank, plus the payload -can be delivered to LEO using a 70 t to LEO upgraded SLS, and can support reusable cargo delivery and crewed lunar landing missions. The NTPS can play an important role in returning humans to the Moon to stay by providing an affordable in-space transportation system that can allow initial lunar outposts to evolve into settlements capable of supporting commercial activities. Over the next decade collaborative efforts between NASA and private industry could open up new exploration and commercial opportunities for both organizations. With efficient NTP, commercial habitation and crew delivery systems, a "mobile cislunar research station" can transport crews to small NEAs delivered to the E-ML2 point. Also possible are week-long "lunar tourism" missions that can carry passengers into lunar orbit for sightseeing (and plenty of picture taking), then return them to Earth orbit where they would re-enter and land using a small reusable lifting body based on NASA's HL-20 design. Mission descriptions, key vehicle features and operational characteristics are described and presented. NomenclatureE-ML2 = Earth-Moon L2 Lagrange point K = temperature (degrees Kelvin) klb f = thrust (1000's of pounds force) LEO = Low Earth Orbit (= 407 km circular) LOX / LH 2 = Liquid Oxygen / Liquid Hydrogen propellant NERVA = Nuclear Engine for Rocket Vehicle Applications SLS / HLV = Space Launch System / Heavy Lift Vehicle SNRE = Small Nuclear Rocket Engine t = metric ton (1 t = 1000 kg) ΔV = velocity change increment (km/s) ---

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“…Initial efforts were focused on benchmarking methods and models against the Small Nuclear Rocket Engine (SNRE) and stage configuration documented in the Nuclear Engine Definition Study (NEDS) Preliminary reports 3,4 . Past papers have addressed neutronics modeling of the SNRE reactor core 5 , the SNRE reference stage 6 , integrated thermal-fluid-structural analysis of reactor core interior components 7 , engine system level modeling and analyses 8 , and an extension of the SNRE design into the 25,000 lbf thrust range 9 . Most nuclear thermal propulsion engine designs utilize uranium fuel enriched to 93 wt% 235 U.…”

Section: Introductionmentioning

confidence: 99%