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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

SEI needs for space nuclear power

The use of nuclear electric propulsion (NEP) and nuclear thermal propulsion (NTP) for transportation to the moon and Mars is examined, and the use on Mars and moon bases of thermal conversion subsystems based on either a Brayton or a Stirling cycle is examined. It is shown that both cycles are attractive alternatives for those applications where continuous field operation is desired. Nuclear power systems have a clear advantage with regard to the moon and a lesser one with regard to Mars.

Brandhorst, H. W.↗
NASA NTRS1996

Electric Propulsion Options for Mars Cargo Missions

This paper summarizes an evaluation of mission performance (in terms of vehicle mass and trip time of solar electric propulsion (SEP) and nuclear electric propulsion (NEP) operating at power levels on the order of 1.5 MW⊆ for Mars cargo missions. The SEP and NEP vehicles are both assumed to use lithium-propellant magnetoplasmadynamic (MPD) thrusters with an efficiency (electric-to-jet) of 60 percent at a specified nominal specific impulse.

SEP↗
NASA NTRSDate not supplied

Application of Analytical Hierarchy Process for Narrowing Down Nep Candidate Reactor Designs

NASA is currently studying the possibility of human exploration of Mars in the late 2030s timeframe using a hybrid nuclear electric propulsion (NEP)/chemical propulsion system. Present analyses indicate such a mission could require a reactor power system in the range of 2 to 6 MWe operating for approximately 3 years. At present, the Technology Readiness Levels (TRL) of key NEP technologies are still low, implying that significant technology development activities must be undertaken prior to making informed design selections for an integrated propulsion system. NASA’s Space Nuclear Propulsion (SNP) project has recently undertaken an in-depth effort to identify NEP candidate technologies and determine the required developmental work to mature these technologies to the point where they could realistically support the design and assembly of a full NEP system. A version of the Analytical Hierarchy Process is being employed to narrow the technology candidates for SNP investment planning. This multi-attribute decision-making process relies on quantified technical inputs and the judgement of Subject Matter Experts (SMEs) to evaluate technology options against key technical and programmatic Figures-of-Merit (FOM) at the subsystem and optimized system level. The process and an example evaluation of nuclear fuel/moderator combinations in a sodium heat pipe honeycomb-geometry reactor concept are described. The evaluation and analysis methodology described in this paper can be employed for pairwise comparisons between reactor concepts and technology choices as new data become available.

Dasari V Rao↗
NASA NTRS1998

Vehicle and Mission Design Options for the Human Exploration of Mars/Phobos Using "Bimodal" NTR and LANTR Propulsion

The nuclear thermal rocket (NTR) is one of the leading propulsion options for future human missions to Mars because of its high specific impulse (Isp-850-1000 s) capability and its attractive engine thrust-to-weight ratio (approximately equal 3-10). To stay within the available mass and payload volume limits of a "Magnum" heavy lift vehicle, a high performance propulsion system is required for trans-Mars injection (TMI). An expendable TMI stage, powered by three 15 thousand pounds force (klbf) NTR engines is currently under consideration by NASA for its Design Reference Mission (DRM). However, because of the miniscule burnup of enriched uranium-235 during the Earth departure phase (approximately 10 grams out of 33 kilograms in each NTR core), disposal of the TMI stage and its engines after a single use is a costly and inefficient use of this high performance stage. By reconfiguring the engines for both propulsive thrust and modest power generation (referred to as "bimodal" operation), a robust, multiple burn, "power-rich" stage with propulsive Mars capture and reuse capability is possible, A family of modular "bimodal" NTR (BNTR) vehicles are described which utilize a common "core" stage powered by three 15 klbf BNTRs that produce 50 kWe of total electrical power for crew life support, an active refrigeration / reliquification system for long term, "zero-boiloff" liquid hydrogen (LH 2 ) storage, and high data rate communications. An innovative, spine-like "saddle truss" design connects the core stage and payload element and is open underneath to allow supplemental "in-line" propellant tanks and contingency crew consumables to be easily jettisoned to improve vehicle performance. A "modified" DRM using BNTR transfer vehicles requires fewer transportation system elements, reduces IMLEO and mission risk, and simplifies space operations. By taking the next logical step--use of the BNTR for propulsive capture of all payload elements into Mars orbit--the power available in Mars orbit grows to 150 kWe compared to 30 kWe for the DRM. Propulsive capture also eliminates the complex, higher risk aerobraking and capture maneuver which is replaced by a simpler reentry using a standardized, lower mass "aerodescent" shell. The attractiveness of the "all BNTR" option is further increased by the substitution of the lightweight, inflatable "TransHab" module in place of the heavier, hard-shell hab module. Use of TransHab introduces the potential for propulsive recovery and reuse of the BNTR/ERV. It also allows the crew to travel to and from Mar on the same BNTR transfer vehicle thereby cutting the duration of the ERV mission in half--from approximately 4.7 to 2.5 years. Finally, for difficult Mars options, such as Phobos rendezvous and sample return missions, volume (not mass) constraints limit the performance of the "all LH 2 " BNTR stage. The use of "LOX-augmented" NTR (LANTR) engines, operating at a modest oxygen-to-hydrogen mixutre ratio (MR) of 0.5, helps to increase "bulk" propellant density and total thrust during the TMI burn. On all subsequent burns, the bimodal LANTR engines operate on LH 2 only (MR=0) to maximize vehicle performance while staying within the lift capability of two Magnum launches.

Nuclear thermal rocket↗
NASA NTRS2002

Vehicle and Mission Design Options for the Human Exploration of Mars/Phobos Using "Bimodal" NTR and LANTR Propulsion

The nuclear thermal rocket (NTR) is one of the leading propulsion options for future human missions to Mars because of its high specific impulse (lsp~850-1000 s) capability and its attractive engine thrust-to-weight ratio (~3-10). To stay within the available mass and payload volume limits of a “Magnum” heavy lift vehicle, a high performance propulsion system is required for trans-Mars injection (TMI). An expendable TMI stage, powered by three 15 thousand pounds force (klbf) NTR engines is currently under consideration by NASA for its Design Reference Mission (DRM). However, because of the miniscule burnup of enriched uranium-235 during the Earth departure phase (~10 grams out of 33 kilograms in each NTR core), disposal of the TMI stage and its engines after a single use is a costly and inefficient use of this high performance stage. By reconfiguring the engines for both propulsive thrust and modest power generation (referred to as “bimodal” operation), a robust, multiple burn, “power-rich” stage with propulsive Mars capture and reuse capability is possible. A family of modular “bimodal” NTR (BNTR) vehicles are described which utilize a common “core” stage powered by three 15 klbf BNTRs that produce 50 kWe of total electrical power for crew life support, an active refrigeration / reliquification system for long term, zero-boiloff liquid hydrogen (LH 2 ) storage, and high data rate communications. An innovative, spine-like “saddle truss” design connects the core stage and payload element and is open underneath to allow supplemental “in-line” propellant tanks and contingency crew consumables to be easily jettisoned to improve vehicle performance. A “modified” DRM using BNTR transfer vehicles requires fewer transportation system elements, reduces IMLEO and mission risk, and simplifies space operations. By taking the next logical step—use of the BNTR for propulsive capture of all payload elements into Mars orbit—the power available in Mars orbit grows to 150 kWe compared to 30 kWe for the DRM. Propulsive capture also eliminates the complex, higher risk aerobraking and capture maneuver which is replaced by a simpler reentry using a standardized, lower mass “aerodescent” shell. The attractiveness of the “all BNTR” option is further increased by the substitution of the lightweight, inflatable “TransHab” module in place of the heavier, hard-shell hab module. Use of TransHab introduces the potential for propulsive recovery and reuse of the BNTR / Earth return vehicle (ERV). It also allows the crew to travel to and from Mars on the same BNTR transfer vehicle thereby cutting the duration of the ERV mission in half—from ~4.7 to 2.5 years. Finally, for difficult Mars options, such as Phobos rendezvous and sample return missions, volume (not mass) constraints limit the performance of the “all LH 2 ” BNTR stage. The use of “LOX-augmented” NTR (LANTR) engines, operating at a modest oxygen-to-hydrogen mixture ratio (MR) of 0.5, helps to increase “bulk” propellant density and total thrust during the TMI burn. On all subsequent burns, the bimodal LANTR engines operate on LH 2 only (MR=0) to maximize vehicle performance while staying within the mass limits of two Magnum launches.

Nuclear thermal rocket↗
NASA NTRSDate not supplied

Optimization Considerations for Annular Linear Electromagnetic Pumps for Space Nuclear Power and Propulsion

The Need for High Performance Liquid Metal Pumps Testing Power and Efficiency Considerations Liquid metal cooled reactors is one option for space nuclear power for settlements and electric propulsion vehicles (Snap 10 A, SP100, Soviet Topaz reactors) • High heat capacity • High boiling point (NaK~1200K) • Simplified heat transfer loop • Good neutronics Liquid metal EM pumps are desired over conventional pumps owing to lack of seals, bearings elimination of cavitation issues, lower mass and eliminates mechanical impeller • Conduction pumps (typically DC-high current, low voltage; ~5% efficiency) • Induction pumps (typically AC, high efficiency ~40%) Annular linear induction pump is an EM pump with no moving parts and of cylindrical/tubular geometry which makes it straightforward to integrate in conventional piping architectures • Higher inherent reliability • Invented by Einstein and Szilard

ALIP↗
NASA NTRSDate not supplied

1.9 MWe Nuclear Electric Propulsion-Chemical Propulsion Piloted Mars Opposition Vehicle

To assess ‘quick’ missions to Mars, a study was performed to determine the feasibility of a two-year roundtrip class mission concept of operation that enables boots on Mars in the 2030s. After performing a Phase 1.1 2036 Mars opposition design case, the more difficult 2039 opposition design was pursued. This Phase 1.2 also sought to further refine the concept, building on feasibility, and addressing several challenges brought by independent team reviews. Given the date of 2039, nearer-term technologies, primarily nuclear thermal and nuclear electric were deemed as the most viable for these missions. This paper explores a nuclear electric and chemical combined propulsion approach to achieve the desired mission timeline.

Nuclear Electric Propulsion↗
NASA NTRS1991

Hybrid propulsion systems for space exploration missions

Combinations of nuclear thermal propulsion (NTP), nuclear electric propulsion (NEP), and chemical propulsion are discussed. Technical details are given in viewgraph form. The characteristics of each configuration are discussed, particularly thrust characteristics.

Darooka, D. K.↗
NASA NTRS1972

Nuclear radiation problems, unmanned thermionic reactor ion propulsion spacecraft

A nuclear thermionic reactor as the electric power source for an electric propulsion spacecraft introduces a nuclear radiation environment that affects the spacecraft configuration, the use and location of electrical insulators and the science experiments. The spacecraft is conceptually configured to minimize the nuclear shield weight by: (1) a large length to diameter spacecraft; (2) eliminating piping penetrations through the shield; and (3) using the mercury propellant as gamma shield. Since the alumina material is damaged by the high nuclear radiation environment in the reactor it is desirable to locate the alumina insulator outside the reflector or develop a more radiation resistant insulator.

Mondt, J. F.↗
NASA NTRS1991

Space Propulsion Technology Program Overview

The topics presented are covered in viewgraph form. Focused program elements are: (1) transportation systems, which include earth-to-orbit propulsion, commercial vehicle propulsion, auxiliary propulsion, advanced cryogenic engines, cryogenic fluid systems, nuclear thermal propulsion, and nuclear electric propulsion; (2) space platforms, which include spacecraft on-board propulsion, and station keeping propulsion; and (3) technology flight experiments, which include cryogenic orbital N2 experiment (CONE), SEPS flight experiment, and cryogenic orbital H2 experiment (COHE).

Escher, William J. D.↗
NASA NTRSDate not supplied

Human Mars Mission In-Space Transportation Sensitivity for Nuclear Electric / Chemical Hybrid Propulsion

NASA's Human Exploration and Operation Mission Directorate is continuing to study different concepts and options to field human Mars missions as part of NASA's Moon2Mars directive. In this study, an update to the Hybrid propulsion system was established with the introduction of nuclear electric propulsion system to replace the solar electric propulsion system in an effort to understand the potential impact of a shorter mission to Mars. For crewed missions to Mars, the transportation system sizing is highly dependent on the type of mission and the mission duration. An integrated trajectory analysis capability has been developed and updated to enable this investigation. Longer duration mission may utilize higher efficiency low thrust propulsion system more, but would require higher payload mass due to increase to crew logistics loading and habitation volume. Conversely, shorter duration mission may have lower payload mass, but will require significant increase to propulsion system performance and/or overall system mass. An overall integrated design trade space is defined in this paper to investigate the tradeoff between these scenarios to illuminate the optimality of the transportation system option from a mass perspective. The sensitivity analysis developed in this study will be crucial to understanding the Mars mission design trade space for crewed Mars missions, and will help inform design decisions and investment strategies.

Patrick R. Chai↗
NASA NTRS1991

Comments on dual-mode nuclear space power and propulsion system concepts

Some form of Dual-Mode Nuclear Space Power & Propulsion System (D-MNSP&PS) will be essential to spacefaring throughout teh solar system and that such systems must evolve as mankind moves into outer space. The initial D-MNPSP&PS Reference System should be based on (1) present (1990), and (2) advanced (1995) technology for use on comparable mission in the 2000 and 2005 time period respectively. D-MNSP&PS can be broken down into a number of subsystems: Nuclear subsystems including the energy source and controls for the release of thermal power at elevated temperatures; power conversion subsystems; waste heat rejection subsystems; and control and safety subsystems. These systems are briefly detailed.

Layton, J. Preston↗