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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Nuclear thermal rockets - Key to moon-Mars exploration

The Space Exploration Initiative (SEI) calls for lunar and Martian exploration missions for which solid-core nuclear thermal rockets (NTRs), in virtue of their single-stage, fully-reusable nature, are ideally suited. NTRs promise double the specific impulse of chemical propulsion. A lunar mission employing a reusable NTR is currently being conducted by NASA. The NTR would be assembled in LEO in such a way that it remained 'radioactively cold' during earth-to-orbit deployment by a heavy-lift chemical booster, and therefore presented no radioactive hazard. Also under consideration is a particle-bed reactor in which the hydrogen propulsive fluid directly cools coated-particle fuel spheres.

Borowski, Stanley K.↗
NASA NTRS1993

Lunar NTR vehicle design and operations study

The results of a lunar nuclear thermal rocket (NTR) vehicle design and operations study are presented in text and graphic form. The objectives of the study were to evaluate the potential applications of a specific NTR design to past and current (First Lunar Outpost) mission profiles for piloted and cargo lunar missions, and to assess the applicability of utilizing lunar vehicle design concepts for Mars missions.

Hodge, John↗
NASA NTRS2003

Future Mission Proposal Opportunities: Discovery, New Frontiers, and Project Prometheus

The NASA Office of Space Science is expanding opportunities to propose missions to comets, asteroids, and other solar system targets. The Discovery Program continues to be popular, with two sample return missions, Stardust and Genesis, currently in operation. The New Frontiers Program, a new proposal opportunity modeled on the successful Discovery Program, begins this year with the release of its first Announcement of Opportunity. Project Prometheus, a program to develop nuclear electric power and propulsion technology intended to enable a new class of high-power, high-capability investigations, is a third opportunity to propose solar system exploration. All three classes of mission include a commitment to provide data to the Planetary Data System, any samples to the NASA Curatorial Facility at Johnson Space Center, and programs for education and public outreach.

Niebur, S. M.↗
NASA NTRS2015

Modular Stirling Radioisotope Generator

High efficiency radioisotope power generators will play an important role in future NASA space exploration missions. Stirling Radioisotope Generators (SRG) have been identified as a candidate generator technology capable of providing mission designers with an efficient, high specific power electrical generator. SRGs high conversion efficiency has the potential to extend the limited Pu-238 supply when compared with current Radioisotope Thermoelectric Generators (RTG). Due to budgetary constraints, the Advanced Stirling Radioisotope Generator (ASRG) was canceled in the fall of 2013. Over the past year a joint study by NASA and DOE called the Nuclear Power Assessment Study (NPAS) recommended that Stirling technologies continue to be explored. During the mission studies of the NPAS, spare SRGs were sometimes required to meet mission power system reliability requirements. This led to an additional mass penalty and increased isotope consumption levied on certain SRG-based missions. In an attempt to remove the spare power system, a new generator architecture is considered which could increase the reliability of a Stirling generator and provide a more fault-tolerant power system. This new generator called the Modular Stirling Radioisotope Generator (MSRG) employs multiple parallel Stirling convertor/controller strings, all of which share the heat from the General Purpose Heat Source (GPHS) modules. For this design, generators utilizing one to eight GPHS modules were analyzed, which provide about 50 to 450 watts DC to the spacecraft, respectively. Four Stirling convertors are arranged around each GPHS module resulting in from 4 to 32 Stirling/controller strings. The convertors are balanced either individually or in pairs, and are radiatively coupled to the GPHS modules. Heat is rejected through the housing/radiator which is similar in construction to the ASRG. Mass and power analysis for these systems indicate that specific power may be slightly lower than the ASRG and similar to the MMRTG. However, the reliability should be significantly increased compared to ASRG.

Stirling Cycle↗
NASA NTRS1982

Historical review and current plans

A space station concept published in Colliers Magazine in 1952 was the result of a proposal made by a group of visionary scientists and engineers. NASA began studies regarding the concepts and technology needed for a space station in 1959 during its first year of existence. Formative studies regarding the design and the construction of a space station are discussed, taking into account the 1960 space station design of an American aerospace company, the scale model of a hexagonal self-deploying space station, the concept of the Manned Orbiting Research Laboratory (MORL), MORL with Apollo Logistics System, the MORL Brayton Cycle power system, MORL with nuclear power, a manned orbiting telescope, the 1967 Large Space Station concept, the phase B modular space station, the MOSC configuration 1975, a basic manned platform with resupply, and a concept for a space operations center studied in 1979. A Soviet space station program began with Salyut 1 in April 1971. The U.S. Skylab was launched in May 1973. Attention is also given to military stations and current planning.

Hook, W. R.↗
NASA NTRS2017

Kilopower: Small and Affordable Fission Power Systems for Space

The Nuclear Systems Kilopower Project was initiated by NASA's Space Technology Mission Directorate Game Changing Development Program in fiscal year 2015 to demonstrate subsystem-level technology readiness of small space fission power in a relevant environment (Technology Readiness Level 5) for space science and human exploration power needs. The Nuclear Systems Kilopower Project centerpiece is the Kilopower Reactor Using Stirling Technology (KRUSTY) test, which consists of the development and testing of a fission ground technology demonstrator of a 1 kWe-class fission power system. The technologies to be developed and validated by KRUSTY are extensible to space fission power systems from 1 to 10 kWe, which can enable higher power future potential deep space science missions, as well as modular surface fission power systems for exploration. The Kilopower Project is cofounded by NASA and the Department of Energy National Nuclear Security Administration (NNSA).KRUSTY include the reactor core, heat pipes to transfer the heat from the core to the power conversion system, and the power conversion system. Los Alamos National Laboratory leads the design of the reactor, and the Y-12 National Security Complex is fabricating it. NASA Glenn Research Center (GRC) has designed, built, and demonstrated the balance of plant heat transfer and power conversion portions of the KRUSTY experiment. NASA MSFC developed an electrical reactor simulator for non-nuclear testing, and the design of the reflector and shielding for nuclear testing. In 2016, an electrically heated non-fissionable Depleted Uranium (DU) core was tested at GRC in a configuration identical to the planned nuclear test. Once the reactor core has been fabricated and shipped to the Device Assembly Facility at the NNSAs Nevada National Security Site, the KRUSTY nuclear experiment will be assembled and tested. Completion of the KRUSTY experiment will validate the readiness of 1 to 10 kWe space fission technology for NASAs future requirements for sunlight-independent space power. An early opportunity for demonstration of In-Situ Resource Utilization (ISRU) capability on the surface of Mars is currently being considered for 2026 launch. Since a space fission system is the leading option for power generation for the first Mars human outpost, a smaller version of a planetary surface fission power system could be built to power the ISRU demonstration and ensure its end-to-end validity. Planning is underway to start the hardware development of this subscale flight demonstrator in 2018.

Space nuclear power↗
NASA NTRSDate not supplied

ENABLING ARCHITECTURE TRADES AND DESIGN EXPLORATION FOR NUCLEAR ELECTRIC PROPULSION

Recent renewed interest in Nuclear Electric Propulsion (NEP) at NASA has driven the need for design space exploration and analysis of alternative architectures to evaluate performance and feasibility of NEP concepts. It has been over a decade since NASA last invested in Nuclear Electric Propulsion development efforts, and the landscape has shifted in both mission objectives and technology readiness levels. This also means that many of the engineering analyses and design frameworks tailored to NEP date back to the Jupiter Icy Moons Orbiter (JIMO) days of the early 2000s. Thus, a need was identified for updating and modernizing the modeling and simulation toolsets for NEP. This paper will detail the development efforts in the Marshall Space Flight Center’s Advanced Concepts Office, with a particular focus on the development of the NEP stage of the NEP-Chem vehicle. The paper will cover the various models used, and their current development status, as well as provide an overview of the integrated vehicle model and plans for further development.

Nuclear↗
NASA NTRS1976

Numerical simulation of tornado wind loading on structures

A numerical simulation of a tornado interacting with a building was undertaken in order to compare the pressures due to a rotational unsteady wind with that due to steady straight winds used in design of nuclear facilities. The numerical simulations were performed on a two-dimensional compressible hydrodynamics code. Calculated pressure profiles for a typical building were then subjected to a tornado wind field and the results were compared with current quasisteady design calculations. The analysis indicates that current design practices are conservative.

Maiden, D. E.↗
NASA NTRS1993

In-space operations for lunar and Mars space transfer vehicles

The objective of this paper is to discuss the in-space operations required to process the lunar and Mars mission vehicles envisioned for the Space Exploration Initiative (SEI). Recent studies, which have examined the degree to which on-orbit operations change as a function of the Earth-to-orbit (ETO) launch vehicle size, identified a common set of on-orbit vehicle processing tasks, and generated functional requirements for in-space processing nodes are summarized in this paper. Timelines for on-orbit processing of two different lunar transfer vehicles (LTV's) were developed to compare a 'current practice,' labor-intensive EVA approach to ones utilizing telerobotics and advanced automation. LTV aerobrake concepts ranging from simple deployment to considerable assembly are compared. Similar timelines for the on-orbit processing of a nuclear Mars transfer vehicle (MTV) are also presented. Aerobrakes can be processed in a timely manner and should not be ruled out for SEI missions. The 'tall pole' time interval for on-orbit vehicle initial processing is the delivery of elements to orbit, not the processing tasks.

Raper, James L., Sr.↗
NASA NTRS2004

Non-nuclear Testing of Reactor Systems in the Early Flight Fission Test Facilities (EFF-TF)

The Early Flight Fission-Test Facility (EFF-TF) can assist in the &sign and development of systems through highly effective non-nuclear testing of nuclear systems when technical issues associated with near-term space fission systems are "non-nuclear" in nature (e.g. system s nuclear operations are understood). For many systems. thermal simulators can he used to closely mimic fission heat deposition. Axial power profile, radial power profile. and fuel pin thermal conductivity can be matched. In addition to component and subsystem testing, operational and lifetime issues associated with the steady state and transient performance of the integrated reactor module can be investigated. Instrumentation at the EFF-TF allows accurate measurement of temperature, pressure, strain, and bulk core deformation (useful for accurately simulating nuclear behavior). Ongoing research at the EFF-TF is geared towards facilitating research, development, system integration, and system utilization via cooperative efforts with DOE laboratories, industry, universities, and other NASA centers. This paper describes the current efforts for the latter portion of 2003 and beginning of 2004.

VanDyke, Melissa↗
NASA NTRS2008

Gas Core Reactor Numerical Simulation Using a Coupled MHD-MCNP Model

Analysis is provided in this report of using two head-on magnetohydrodynamic (MHD) shocks to achieve supercritical nuclear fission in an axially elongated cylinder filled with UF4 gas as an energy source for deep space missions. The motivation for each aspect of the design is explained and supported by theory and numerical simulations. A subsequent report will provide detail on relevant experimental work to validate the concept. Here the focus is on the theory of and simulations for the proposed gas core reactor conceptual design from the onset of shock generations to the supercritical state achieved when the shocks collide. The MHD model is coupled to a standard nuclear code (MCNP) to observe the neutron flux and fission power attributed to the supercritical state brought about by the shock collisions. Throughout the modeling, realistic parameters are used for the initial ambient gaseous state and currents to ensure a resulting supercritical state upon shock collisions.

Kazeminezhad, F.↗
NASA NTRSDate not supplied

NASA’s Radioisotope Power Systems Program: Status Update

Radioisotope power systems (RPS) have safely been in use in the United States for over 60 years. RPS-enabled NASA missions have utilized space nuclear power to explore planets, moons, and interstellar space. This exploration resulted in changes to our understanding of our Solar System and our place within it. In 2010, NASA HQ established a NASA program to invest in RPS technologies and systems that could enable future missions. The RPS Program ensures the availability of RPS for the exploration of the solar system in environments where conventional solar or chemical power generation is impractical or impossible. The RPS Program, in partnership with the Department of Energy (DOE) Office of Nuclear Energy continues to operate as an interagency partnership to provide robust power system solutions to spacecrafts that conduct missions for exploration and science that otherwise would not be feasible. This paper provides a synopsis of current activities after well over a decade of formal interagency partnering.

Radioisotope↗
NASA NTRS1996

Overview of nuclear fragmentation models and needs

It has been known for some time that adequate assessment of spacecraft shield requirements and concomitant estimates of astronauts radiation exposures from galactic cosmic radiation requires accurate, quantitative methods for characterizing these radiation fields as they pass through thick absorbers. The main nuclear interaction processes involved are (1) nuclear elastic and inelastic collisions, and (2) nuclear breakup (fragmentation) and electromagnetic dissociation (EMD). Nuclear fragmentation and EMD are important because they alter the elemental and isotopic composition of the transported radiation fields. At present, there is no suitably accurate theory for predicting nuclear fragmentation cross sections for all collision pairs and energies of interest in space radiation protection. Typical cross-section differences between theory and experiment range from about 25 percent to a factor of two. The resulting errors in transported flux, for high linear energy transfer (LET) particles, are comparble to these cross-section errors. In this overview, theoretical models of heavy ion fragmentation currently used to generate input data bases for cosmic-ray transport and shielding codes are reviewed. Their shortcomings are discussed. Further actions needed to improve their accuracy and generality are presented.

Review↗
NASA NTRS1991

Thermion: Verification of a thermionic heat pipe in microgravity

The Idaho National Engineering Laboratory (INEL) is conducting intensive research in the design and development of a small excore heat-pipe-thermionic space nuclear reactor power system (SEHPTR). The SEHPTR spacecraft will be able to supply 40 kW of power in any given orbit. The key components in this reactor are the thermionic heat pipes. The heat pipes have two major functions: (1) to convert heat energy into electrical energy, and (2) to radiate the excess heat to space. Thermionic power conversion is the process of converting heat energy into electrical energy with no moving parts. Heat is applied to the cathode surface. This heat will boil off electrons that will jump across the gap to the cooler surface of the anode, which will cause a potential difference between the two plates and induce a current through the load. Thermionic power conversion is incorporated as part of the heat pipe. The heat pipe, which is being developed by Thermacore Inc., is actually two heat pipes. It uses a radial heat pipe, called the emitter, and an axial heat pipe collector. The emitter heat pipe will pass the heat from the nuclear core to the cathode surface. The collector heat pipe keeps the anode surface cooler by transferring the heat from the anode surface and radiating it to space.

Source record↗
NASA NTRS1988

Beyond the Station

The NASA Pathfinder program for sending humans and robots to explore the solar system is discussed. The various technologies which are to be developed to support the program are described, emphasizing technology for an in-situ resource-processing plant for production of oxygen on the moon and space nuclear power for propulsion to the outer planets. The use of Pathfinder to validate advanced propulsion concepts and the use of aerobraking to land on Mars are discussed. Communications between Mars and earth are addressed. Mission scenarios currently under consideration for Pathfinder are examined.

Mankins, John C.↗
NASA NTRS1992

Hubble Space Telescope imaging of distant galaxies - 4C 41.17 at z = 3.8

The Hubble Space Telescope has been used to image the continuum emission from 4C 41.17 at z = 3.8, the most distant galaxy known. The galaxy was detected with good signal-to-noise ratio and was spatially resolved at the 0.1 arcsec (440 pc) HST resolution. About 35 percent of this emission is in the form of a high brightness clumpy region extending by about 0.5 arcsec (1.7 kpc), whose morphology is remarkably similar to that of the radio components. A fainter more diffuse region of optical emission extends westward from the center of the nuclear complex for about 1.2 arcsec (5.3 kpc) out along the radio axis. The clumpiness of the optical emission and its close correspondence with the radio structure on the subkiloparsec scale is discussed in the light of current models for high-redshift galaxies. Our observations imply that the material in the center of this galaxy is clumpy on the subkiloparsec scale.

Miley, G. K.↗
NASA NTRS2008

Recent Low-Earth Orbit Radiation Measurements Using Passive Dosimeters during ISS Expeditions 13, 14 and 15

Current passive radiation measurements in low-Earth orbit (LEO) involve using a combination of thermally/optically stimulated luminescence detectors (TLDs/OSLDs) for the low-LET component (LET<10 keV/micron water) of the space radiation field and plastic nuclear track detectors (PNTDs) for the high-LET region (LET>10 keV/micron water), as per National Council on Radiation Protection recommendation (NCRP 132, 2004). This combination of radiation detectors has been successfully implemented at NASA Johnson Space Center for routine crewmember and ISS area monitoring using LiF:Mg,Ti, CaF2:Tm, Al2O3:C and CR-39 material. This paper will present in detail the measurement and data processing techniques employed for passive space radiation measurements by the Space Radiation Analysis Group (SRAG) at JSC. The paper will also summarize the absorbed dose, dose equivalent and quality factor results for the area monitoring during ISS Expeditions 13, 14 and 15.

Gaza, R.↗
NASA NTRS2008

Advanced Thermal Simulator Testing: Thermal Analysis and Test Results

Work at the NASA Marshall Space Flight Center seeks to develop high fidelity, electrically heated thermal simulators that represent fuel elements in a nuclear reactor design to support non-nuclear testing applicable to the development of a space nuclear power or propulsion system. Comparison between the fuel pins and thermal simulators is made at the outer fuel clad surface, which corresponds to the outer sheath surface in the thermal simulator. The thermal simulators that are currently being tested correspond to a SNAP derivative reactor design that could be applied for Lunar surface power. These simulators are designed to meet the geometric and power requirements of a proposed surface power reactor design, accommodate testing of various axial power profiles, and incorporate imbedded instrumentation. This paper reports the results of thermal simulator analysis and testing in a bare element configuration, which does not incorporate active heat removal, and testing in a water-cooled calorimeter designed to mimic the heat removal that would be experienced in a reactor core.

Bragg-Sitton, Shannon M.↗