Search NASA⌕ Search

SEARCH · Search NASA

Results for “NEP electric propulsion”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Reactor design and integration into a nuclear electric spacecraft

One of the well-defined applications for nuclear power in space is nuclear electric propulsion (NEP). Mission studies have identified the optimum power level (400 kWe). A single Shuttle launch requirement and science-package integration have added additional constraints to the design. A reactor design which will meet these constraints has been studied. The reactor employs 90 fuel elements, each heat pipe cooled. Reactor control is obtained with BeO/B4C drums in a BeO reflector. The balance of the spacecraft is shielded from the reactor with LiH. Power conditioning and reactor control drum drives are located behind the LiH with the power conditioning. Launch safety, mechanical design and integration with the power conversion subsystem are discussed.

Phillips, W. M.↗
NASA NTRS1980

An interstellar precursor mission

A mission out of the planetary system, launched about the year 2000, could provide valuable scientific data as well as test some of the technology for a later mission to another star. Primary scientific objectives for the precursor mission concern characteristics of the heliopause, the interstellar medium, stellar distances (by parallax measurements), low-energy cosmic rays, interplanetary gas distribution, and the mass of the solar system. Secondary objectives include investigation of Pluto. The mission should extend to 400-1000 AU from the sun. A heliocentric hyperbolic escape velocity of 50-100 km/sec or more is needed to attain this distance within a reasonable mission duration (20-50 years). The trajectory should be toward the incoming interstellar gas. For a year 2000 launch, a Pluto encounter and orbiter can be included. A second mission targeted parallel to the solar axis would also be worthwhile. The mission duration is 20 years, with an extended mission to a total of 50 years. A system using one or two stages of nuclear electric propulsion (NEP) was selected as a possible baseline. The most promising alternatives are ultralight solar sails or laser sailing, with the lasers in earth orbit, for example. The NEP baseline design allows the option of carrying a Pluto orbiter as a daughter spacecraft.

Jaffe, L. D.↗
NASA NTRS1981

Nuclear Electric Propulsion - A concept for solar system exploration

The potential of Nuclear Electric Propulsion (NEP) to meet the increasing demands of our planetary space exploration program is examined and evaluated. Based on an assumption of a modest growth beyond current technology, an NEP system is described that provides performance advantage over all competitive technologies. Flight times and available payload mass - as indicators of mission performance - are compared for several mission opportunities of interest. NEP is shown to have a unique capacity for substantial reductions in mission flight times in terms of payloads consistent with the needs of planetary exploration.

Nagorski, R. P.↗
NASA NTRS1982

Nuclear electric propulsion /NEP/ spacecraft for the outer planet orbiter mission

The design, operating features, and a possible Neptune orbit for the spacecraft powered by the SP-100 nuclear electric propulsion (NEP) system under study by NASA and the DOE are described. The system features a reactor and a payload situated on opposite ends of a 0.5 m diam, 11 m long astromast. Mercury-ion thrusters are located beneath the reactor for side thrusting, and no contamination of the payload or obstruction of the viewing angles for scientific objectives occurs with the system, which would not degrade in performance even under high insolation during near-sun maneuvers. Results of a theoretical study of earth escapes are presented to show that an NEP powered spiral trajectory out of a 700 km Shuttle orbit and using a Triton gravity assist would be superior to departing from a 300 km orbit with a Centaur boost. The mission profile includes a 1249 kg Galileo payload. The SP-100 has a 1.4 MWth reactor with UO2 fuel tiles and weighs 19,904 kg.

Garrison, P. W.↗
NASA NTRS1985

Ion propulsion technology requirements for planetary mission applications

Integrating a clustered, four engine ion propulsion system to the Mariner Mark II spacecraft is shown to reduce total trip time for the five proposed Mariner Mark II missions by fifteen years. In addition, this advanced Solar Electric Propulsion (SEP) system enables rendezvous encounters with five main belt asteroids rather than one. A precursor Advanced Capability Explorer (ACE) technology demonstration vehicle is proposed to investigate SEP spacecraft interaction and control requirements in support of these future mission opportunities. It is shown that the ACE spacecraft could be assembled from existing residual hardware, protoflight equipment and commercially available flight tested components. The ion propulsion system requirements to support ambitious Nuclear Electric Propulsion (NEP) missions are also examined and specific technology development objectives presented.

Aston, G.↗
NASA NTRS1986

Multimegawatt nuclear electric propulsion - First order system design and performance evaluation

The development of space nuclear power supplies capable of delivering high levels of power (1 to 10 MWe) for long life (5 to 10 years) is being considered. An important potential application of these systems will be to provide power for advanced electric propulsion devices such as ion thrusters or Magneto-Plasma-Dynamic (MPD) thrusters. High-powered Nuclear Electric Propulsion (NEP) concepts based on both ion and MPD thrusters are reviewed. To allow for mission performance evaluation, power supply, power processing, and thruster subsystems are characterized for both ion and MPD propulsion systems designed for operation in the 1 to 10 MWe power range. Several proposed missions which are significantly enhanced by the performance potential of these devices are investigated. Studied missions include near-earth orbit raising, cis-lunar cargo transportation, and planetary exploration. If developed, these 1 to 10 MWe NEP systems may provide a technological base for the development of even larger propulsion systems with power levels of up to hundreds of megawatts. The potential performance and technologies associated with such ultra-high-powered NEP systems is explored.

Sercel, J. C.↗
NASA NTRS1986

Nuclear electric propulsion

We investigate the feasibility of using nuclear electric propulsion (NEP) for slow "freighter" ships traveling from a 500 km low Earth orbit {LEO) to the Moon's orbit about the Earth, and on to Mars. NEP is also shown to be feasible for transporting people to Mars on long conjunction-class missions lasting about nine months one way, and on short "sprint" missions lasting four months one way. Generally, we have not attempted to optimize ion exhaust velocities, but rather we have chosen suitable parameters to demonstrate NEP feasibility. Various combinations of missions are compared with chemical and nuclear thermal propulsion (NTR) systems. Typically, NEP and NTR can accomplish the same lifting task with similar mass in LEO. When compared to chemical propulsion, NEP was found to accomplish the same missions with 40% less mass in LEO. These findings are sufficiently encouraging as to merit further studies with optimum systems.

Paul W Keaton↗
NASA NTRS1987

Preliminary scientific rationale for a voyage to a thousand astronomical units

A proposed mission to 1000 astronomical units (TAU) is under study by the Jet Propulsion Laboratory. Launch date for a TAU mission is likely to be well into the first decade of the 21st century. Study of TAU has focused on the technologies required to carry out this ambitious mission and the identification of preliminary scientific rationale for such a deep space flight. A 1-MW nuclear-powered electric propulsion (NEP) system forms the baseline method for achieving the high velocities required. A solar system escape velocity of 106 km/s is needed to propel the TAU vehicle to 1000 AU in 50 years. The NEP system must accelerate the vehicle for about ten years before this velocity is attained because of the extremely low thrust nature of the xenon-fueled ion engines. At the end of the thrusting phase the NEP system is jettisoned to allow the TAU spacecraft and science experiments to coast out to 1000 AU. Another important technology for TAU is advanced optical communication systems, which are envisioned for transmitting science data to Earth. A 1-m optical telescope combined with a 10-W laser transponder can transmit 20 kbps to a 10-m Earth-orbit-based telescope from 1000 AU.

Etchegaray, M. I.↗
NASA NTRS1987

TAU - A mission to a thousand astronomical units

The potential of nuclear electric propulsion (NEP) is investigated as the enabling technology for achieving a mission to a thousand astronomical units within 50 years duration. By means of a 1000 AU baseline, the primary objective is to make measurements of distances to the stars in the Galaxy and beyond. In addition, several deep space unique studies in astronomy, astrophysics, cosmology, and space plasma physics can be carried out. NEP technology requirements for a mission to 1000 AU are addressed. These technology requirements are compared with current plans for both nuclear space power and ion propulsion research. And finally an example TAU spacecraft system is described.

Nock, K. T.↗
NASA NTRS1989

Propulsive options for a manned Mars transportation system

In this investigation, five potential manned Mars transportation systems are compared. These options include: (1) a single vehicle, chemically propelled (CHEM) option, (2) a single vehicle, nuclear thermal propulsion (NTP) option, (3) a single vehicle solar electric propulsion (SEP) option, (4) a single vehicle hybrid nuclear electric propulsion (NEP)/CHEM option, and (5) a dual vehicle option (NEP cargo spacecraft and CHEM manned vehicle). In addition to utilizing the initial vehicle weight in low-earth orbit as a measure of mission feasibility, this study addresses the major technological barriers each propulsive scenario must surpass. It is shown that instead of a single clearly superior propulsion system, each means of propulsion may be favored depending upon the specified program policy and the extent of the desired manned flight time. Furthermore, the effect which aerobraking and multiple transfer cycles have upon mission feasibility is considered.

Braun, Robert D.↗
NASA NTRS1990

A radiological assessment of nuclear power and propulsion operations near Space Station Freedom

Scenarios were identified which involve the use of nuclear power systems in the vicinity of Space Station Freedom (SSF) and their radiological impact on the SSF crew was quantified. Several of the developed scenarios relate to the use of SSF as an evolutionary transportation node for lunar and Mars missions. In particular, radiation doses delivered to SSF crew were calculated for both the launch and subsequent return of a Nuclear Electric Propulsion (NEP) cargo vehicle and a Nuclear Thermal Rocket (NTR) personnel vehicle to low earth orbit. The use of nuclear power on co-orbiting platforms and the storage and handling issues associated with radioisotope power systems were also explored as they relate to SSF. A central philosophy in these analyses was the utilization of a radiation dose budget, defined as the difference between recommended dose limits from all radiation sources and estimated doses received by crew members from natural space radiations. Consequently, for each scenario examined, the dose budget concept was used to identify and quantify constraints on operational parameters such as launch separation distances, returned vehicle parking distances, and reactor shutdown times prior to vehicle approach. The results indicate that realistic scenarios do not exist which would preclude the use of nuclear power sources in the vicinity of SSF. The radiation dose to the SSF crew can be maintained at safe levels solely by implementing proper and reasonable operating procedures.

Bolch, Wesley E.↗
NASA NTRS1990

Enhancing space transportation: The NASA program to develop electric propulsion

The NASA Office of Aeronautics, Exploration, and Technology (OAET) supports a research and technology (R and T) program in electric propulsion to provide the basis for increased performance and life of electric thruster systems which can have a major impact on space system performance, including orbital transfer, stationkeeping, and planetary exploration. The program is oriented toward providing high-performance options that will be applicable to a broad range of near-term and far-term missions and vehicles. The program, which is being conducted through the Jet Propulsion Laboratory (JPL) and Lewis Research Center (LeRC) includes research on resistojet, arcjets, ion engines, magnetoplasmadynamic (MPD) thrusters, and electrodeless thrusters. Planning is also under way for nuclear electric propulsion (NEP) as part of the Space Exploration Initiative (SEI).

Bennett, Gary L.↗
NASA NTRS1991

Stacking the odds in favor of a space propulsion jackpot

When faced with a variety of technical options to solve a problem, program planners often try to identify one potential winner, then channel their resources into this option. The more scarce their resources are perceived to be, the more likely they are to fall into this trap of illogic. The real ideal solution could well be an optimum combination of options, not just one. Many propulsion opportunities are tantalizing solutions to the potentially high cost of travelling to other planets. Among these opportunities, nuclear thermal rockets (NTR), nuclear electric propulsion (NEP), and asteroid derived propellants stand out as high-payoff modest-challenge options, as near term as they are resolved to be made. But which to choose? Or should higher risk higher payoff technology be opted for, such as fusion? The approach advocated here, technoflex, is one that addresses NTR, NEP, and asteroid propellants in harmony rather than in isolation. Technoflex is technology rich, and option flexible. Technoflex should cost roughly the same as a classic phased technology elimination approach. The synergistic benefits amongst these three options, how they can be efficiently pursued together, and how they can fit with longer range technologies are stressed. Even if no single option reaches its highest expectations, the combinations of any two partial winners would still give big dividends. These combinations are cheap propellants in space, dual mode high thrust/low thrust, or versatile propellant NTR. The triple payoff is excellent, even if all three options would pan out below expectations. If only one option reaches its potential, it could make the other two still worth their investment. If all three options meet full expectations, the triple payoff is a space propulsion jackpot which makes concern about the initial investment ludicrous as well as open up the solar system to expedient exploration.

Willoughby, Alan J.↗
NASA NTRS1990

A potassium Rankine multimegawatt nuclear electric propulsion concept

Multimegawatt nuclear electric propulsion (NEP) has been identified as a potentially attractive option for future space exploratory missions. A liquid-metal-cooled reactor, potassium Rankine power system that is being developed is suited to fulfill this application. The key features of the nuclear power system are described, and system characteristics are provided for various potential NEP power ranges and operational lifetimes. The results of recent mission studies are presented to illustrate some of the potential benefits to future space exploration to be gained from high-power NEP. Specifically, mission analyses have been performed to assess the mass and trip time performance of advanced NEP for both cargo and piloted missions to Mars.

Baumeister, E.↗
NASA NTRS1991

Synergistic use of high and low thrust propulsion systems for piloted missions to Mars

The use of high-thrust, relatively-low-specific-impulse systems, such as chemical or nuclear thermal propulsion, in conjunction with low thrust, high-specific-impulse nuclear electric propulsion (NEP), has been considered for a representative piloted Mars mission. It is concluded that the single-burn option in an all-propulsive mission scenario does not yield a significant performance advantage in reduced trip time for reasonable masses. The multiple burn option allows significant reductions in trip time relative to the NEP system, and may provide a performance advantage over nuclear thermal propulsion depending upon the system assumptions. The combined systems serve to reduce NEP power requirements for fast trip times, and to reduce high thrust systems' sensitivity to mission opportunity. It is considered that 5 kg/kWe systems can provide significant improvements in mass and trip time over the single systems at power levels of 5 to 10 MWe.

Gilland, James H.↗
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 NTRS1991

Nuclear electric propulsion mission performance for fast piloted Mars missions

A mission study aimed at minimizing the time humans would spend in the space environment is presented. The use of nuclear electric propulsion (NEP), when combined with a suitable mission profile, can reduce the trip time to durations competitive with other propulsion systems. Specifically, a split mission profile utilizing an earth crew capture vehicle accounts for a significant portion of the trip time reduction compared to previous studies. NEP is shown to be capable of performing fast piloted missions to Mars at low power levels using near-term technology and is considered to be a viable candidate for these missions.

Hack, K. J.↗
NASA NTRS1991

Multi-reactor power system configurations for multimegawatt nuclear electric propulsion

A modular, multi-reactor power system and vehicle configuration for piloted nuclear electric propulsion (NEP) missions to Mars is presented. Such a design could provide enhanced system and mission reliability, allowing a comfortable safety margin for early manned flights, and would allow a range of piloted and cargo missions to be performed with a single power system design. Early use of common power modules for cargo missions would also provide progressive flight experience and validation of standardized systems for use in later piloted applications. System and mission analysis are presented to compare single and multi-reactor configurations for piloted Mars missions. A conceptual design for the Hydra modular multi-reactor NEP vehicle is presented.

George, Jeffrey A.↗