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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 181 records · Page 10

Electric propulsion technology

The advanced electric propulsion program is directed towards lowering the specific impulse and increasing the thrust per unit of ion thruster systems. In addition, electrothermal and electromagnetic propulsion technologies are being developed to attempt to fill the gap between the conventional ion thruster and chemical rocket systems. Most of these new concepts are exagenous and are represented by rail accelerators, ablative Teflon thrusters, MPD arcs, Free Radicals, etc. Endogenous systems such as metallic hydrogen offer great promise and are also being pursued.

Finke, R. C.↗

Parasitic current losses due to solar electric propulsion generated plasmas

Solar electric propulsion is a leading candidate for many upcoming space missions. Under many circumstances plasma produced by charge-exchange reactions within the ion beam dominates the ambient environment near the spacecraft. The calculations presented here contain a predictive hydrodynamic model for the charge-exchange plasma expansion, and a fully three-dimensional model for the structure of the plasma sheath around the solar array wing. Results of calculations for several configurations and voltage levels indicate that with kilovolt biases power losses of approximately 10 percent or more are likely, even with only one engine in operation, and that ameliorative measures should focus on the inboard portion of the solar arrays.

Katz, I.↗

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.↗

Space transfer concepts and analysis for exploration missions. Implementation plan and element description document (draft final). Volume 5: Nuclear electric propulsion vehicle

The nuclear electric propulsion (NEP) concept design developed in support of the Space Transfer Concepts and Analysis for Exploration Missions (STCAEM) study is presented. The evolution of the NEP concept is described along with the requirements, guidelines, and assumptions for the design. Operating modes and options are defined and a systems description of the vehicle is presented. Artificial gravity configuration options and space and ground support systems are discussed. Finally, an implementation plan is presented which addresses technology needs, schedules, facilities and costs.

Source record↗

A large high vacuum, high pumping speed space simulation chamber for electric propulsion

Testing high power electric propulsion devices poses unique requirements on space simulation facilities. Very high pumping speeds are required to maintain high vacuum levels while handling large volumes of exhaust products. These pumping speeds are significantly higher than those available in most existing vacuum facilities. There is also a requirement for relatively large vacuum chamber dimensions to minimize facility wall/thruster plume interactions and to accommodate far field plume diagnostic measurements. A 4.57 m (15 ft) diameter by 19.2 m (63 ft) long vacuum chamber at NASA Lewis Research Center is described. The chamber utilizes oil diffusion pumps in combination with cryopanels to achieve high vacuum pumping speeds at high vacuum levels. The facility is computer controlled for all phases of operation from start-up, through testing, to shutdown. The computer control system increases the utilization of the facility and reduces the manpower requirements needed for facility operations.

Grisnik, Stanley P.↗

Thrust Stand for Electric Propulsion Performance Evaluation

An electric propulsion thrust stand capable of supporting thrusters with total mass of up to 125 kg and 1 mN to 1 N thrust levels has been developed and tested. The mechanical design features a conventional hanging pendulum arm attached to a balance mechanism that transforms horizontal motion into amplified vertical motion, with accommodation for variable displacement sensitivity. Unlike conventional hanging pendulum thrust stands, the deflection is independent of the length of the pendulum arm, and no reference structure is required at the end of the pendulum. Displacement is measured using a non-contact, optical linear gap displacement transducer. Mechanical oscillations are attenuated using a passive, eddy current damper. An on-board microprocessor-based level control system, which includes a two axis accelerometer and two linear-displacement stepper motors, continuously maintains the level of the balance mechanism - counteracting mechanical %era drift during thruster testing. A thermal control system, which includes heat exchange panels, thermocouples, and a programmable recirculating water chiller, continuously adjusts to varying thermal loads to maintain the balance mechanism temperature, to counteract thermal drifts. An in-situ calibration rig allows for steady state calibration both prior to and during thruster testing. Thrust measurements were carried out on a well-characterized 1 kW Hall thruster; the thrust stand was shown to produce repeatable results consistent with previously published performance data.

Markusic, T. E.↗

Thrust Stand for Electric Propulsion Performance Evaluation

An electric propulsion thrust stand capable of supporting testing of thrusters having a total mass of up to 125 kg and producing thrust levels between 100 microN to 1 N has been developed and tested. The design features a conventional hanging pendulum arm attached to a balance mechanism that converts horizontal deflections produced by the operating thruster into amplified vertical motion of a secondary arm. The level of amplification is changed through adjustment of the location of one of the pivot points linking the system. Response of the system depends on the relative magnitudes of the restoring moments applied by the displaced thruster mass and the twisting torsional pivots connecting the members of the balance mechanism. Displacement is measured using a non-contact, optical linear gap displacement transducer and balance oscillatory motion is attenuated using a passive, eddy-current damper. The thrust stand employs an automated leveling and thermal control system. Pools of liquid gallium are used to deliver power to the thruster without using solid wire connections, which can exert undesirable time-varying forces on the balance. These systems serve to eliminate sources of zero-drift that can occur as the stand thermally or mechanically shifts during the course of an experiment. An in-situ calibration rig allows for steady-state calibration before, during and after thruster operation. Thrust measurements were carried out on a cylindrical Hall thruster that produces mN-level thrust. The measurements were very repeatable, producing results that compare favorably with previously published performance data, but with considerably smaller uncertainty.

Polzin, Kurt A.↗

A Smoothed Eclipse Model for Solar Electric Propulsion Trajectory Optimization

Solar electric propulsion (SEP) is the dominant design option for employing low-thrust propulsion on a space mission. Spacecraft solar arrays power the SEP system but are subject to blackout periods during solar eclipse conditions. Discontinuity in power available to the spacecraft must be accounted for in trajectory optimization, but gradient-based methods require a differentiable power model. This work presents a power model that smooths the eclipse transition from total eclipse to total sunlight with a logistic function. Example trajectories are computed with differential dynamic programming, a second-order gradient-based method.

trajectory design↗

A Smoothed Eclipse Model for Solar Electric Propulsion Trajectory Optimization

Solar electric propulsion (SEP) is the dominant design option for employing low-thrust propulsion on a space mission. Spacecraft solar arrays power the SEP system but are subject to blackout periods during solar eclipse conditions. Discontinuity in power available to the spacecraft must be accounted for in trajectory optimization, but gradient-based methods require a differentiable power model. This work presents a power model that smooths the eclipse transition from total eclipse to total sunlight with a logistic function. Example trajectories are computed with differential dynamic programming, a second-order gradient-based method.

optimization↗

Electric propulsion and power

The development of electric propulsion systems is discussed and the benefits of these systems to various space mission requirements are outlined. The characteristics and development status of 8 and 30 cm mercury ion thrusters and solar electric propulsion systems are reported. In addition the advantages of an inert gas thruster for Earth orbital missions are examined and include its capability for operation at higher values of specific impulse, the ease at which it can be integrated with space systems, and it's low pollution potential.

Byers, D. C.↗

Electric Propulsion Research and Development at NASA

Electric propulsion (EP) is an important technology for NASA. It has played a major role on three missions, that is Deep Space 1, Dawn and Space Technology 7, and it is planned for use on many more. The ion propulsion system for the ongoing Dawn mission has achieved several notable accomplishments, including providing a total velocity change (V) of over 11 km/s to the spacecraft. As a result of these successes, solar electric propulsion (SEP) is now broadly recognized as an essential technology for both robotic and human exploration. NASA is currently conducting many projects focused on research and development of EP for a variety of applications. All three of NASA’s mission directorates that deal directly with space exploration are actively engaged in supporting work in this area. This paper describes these projects in more detail, including the specific engineering activities being conducted at NASA’s main centers for EP technology development, namely Glenn Research Center (GRC) and the Jet Propulsion Laboratory (JPL).

Hofer, Richard↗

Electric Propulsion Research and Development at NASA

Electric propulsion (EP) is an important technology for NASA. It has played a major role on three missions, that is Deep Space 1, Dawn and Space Technology 7, and it is planned for use on many more. The ion propulsion system for the ongoing Dawn mission has achieved several notable accomplishments, including providing a total velocity change (delta-V) of over 11 km/s to the spacecraft. As a result of these successes, solar electric propulsion (SEP) is now broadly recognized as an essential technology for both robotic and human exploration. NASA is currently conducting many projects focused on research and development of EP for a variety of applications. All three of NASA's mission directorates that deal directly with space exploration are actively engaged in supporting work in this area. This paper describes these projects in more detail, including the specific engineering activities being conducted at NASA's main centers for EP technology development, namely Glenn Research Center (GRC) and the Jet Propulsion Laboratory (JPL).

Schmidt, George↗

Electric Propulsion Research and Development at NASA

Electric propulsion (EP) is an important technology for NASA. It has played a major role on three missions, that is Deep Space 1, Dawn and Space Technology 7, and it is planned for use on many more. The ion propulsion system for the ongoing Dawn mission has achieved several notable accomplishments, including providing a total velocity change (delta-V) of over 11 km/s to the spacecraft. As a result of these successes, solar electric propulsion (SEP) is now broadly recognized as an essential technology for both robotic and human exploration. NASA is currently conducting many projects focused on research and development of EP for a variety of applications. All three of NASA's mission directorates that deal directly with space exploration are actively engaged in supporting work in this area. This paper describes these projects in more detail, including the specific engineering activities being conducted at NASA's main centers for EP technology development, namely Glenn Research Center (GRC) and the Jet Propulsion Laboratory (JPL).

Schmidt, George↗

Electric Propulsion Research and Development at NASA

Electric propulsion (EP) is an important technology for NASA. It has played a major role on three missions, namely Deep Space 1, Dawn and Space Technology 7, and it is planned for use on many more. The ion propulsion system for the ongoing Dawn mission has achieved several notable accomplishments, including providing a total velocity change (delta-V) of over 11 km/s to the spacecraft. As a result of these successes, solar electric propulsion (SEP) is now broadly recognized as an essential technology for both robotic and human exploration. NASA is currently conducting many projects focused on research and development of EP for a variety of applications. All three of NASA's mission directorates that deal directly with space exploration are actively engaged in supporting work in this area. This paper describes these projects in more detail, including the specific engineering activities being conducted at NASA's main centers for EP technology development, namely Glenn Research Center (GRC) and the Jet Propulsion Laboratory (JPL).

Schmidt, George↗

Electric Propulsion Research and Development at NASA

Electric propulsion (EP) is an important technology for NASA. It has played a major role on three missions, namely Deep Space 1, Dawn and Space Technology 7, and it is planned for use on many more. The ion propulsion system for the ongoing Dawn mission has achieved several notable accomplishments, including providing a total velocity change (delta-V) of over 11 km/s to the spacecraft. As a result of these successes, solar electric propulsion (SEP) is now broadly recognized as an essential technology for both robotic and human exploration. NASA is currently conducting many projects focused on research and development of EP for a variety of applications. All three of NASA's mission directorates that deal directly with space exploration are actively engaged in supporting work in this area. This paper describes these projects in more detail, including the specific engineering activities being conducted at NASA's main centers for EP technology development, namely Glenn Research Center (GRC) and the Jet Propulsion Laboratory (JPL).

Schmidt, George↗