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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Plasma Chemical Conversion and Resource Generation Beyond Low-Earth Orbit

As humanity gears up for its return to the moon after more than half a century, collaborative efforts between NASA, Artemis Accords Partners, and private industry are underway to establish the necessary infrastructure and technologies for lunar habitation and eventual Mars exploration. However, the traditional ISS resupply and waste management model is impractical and economically infeasible for prolonged missions to the Moon and Mars. Advanced chemical conversion technologies are needed to generate vital consumable products from local planetary resources (ISRU) and recycled gasses and waste within semi-closed loop life-support systems. Low-temperature plasma reactors are emerging power-to-gas technologies with the potential to facilitate various chemical synthesis processes with hardware commonality and redundancy. In plasma-based systems, electrical power is used to ionize a feedstock gas, creating a highly reactive environment that leverages electron excitation chemistry to break stable molecular bonds and form value added products. Unlike thermal chemical processes, plasma reactors operate at non-equilibrium conditions, allowing for lower-temperature operation and instantaneous start-up, making them adaptable to intermittent power availability. Moreover, their scalability permits deployment in both portable astronaut systems and large-scale industrial setups for colonies. One promising application of plasmas is for CO 2 conversion. Carbon dioxide comprises 96% of the Martian atmosphere and is a byproduct of human respiration, which typically must be scrubbed and vented from space habitats. A plasma source integrated with membrane separation technology could generate a stream of oxygen for life support and rocket propellant. CO 2 splitting may also be beneficial as a precursor to manufacture carbon-based products and fuels in situ, like methane, methanol, and polyethylene. Plasma-assisted CO 2 conversion is a simpler case to study without the concern of selectivity and is the first step toward complex chemical synthesis. This work presents preliminary experimental case study from a plasma reactor for CO 2 conversion and casts a vision for the potential of plasma technologies in a sub-architecture for resource production to enable the next generation of human spaceflight activities.

Plasma↗
NASA NTRS1985

Review of the critical ionization velocity effect in space

Laboratory experiments have shown under a variety of conditions that when a neutral gas passes through a magnetized plasma with a relative velocity perpendicular to the magnetic field that is greater than a critical velocity, anomalously high ionization of the neutrals occurs. The conditions under which the same effect is to be expected in space plasmas is still unclear. The experimental evidence for the occurrence of the critical ionization velocity effect in space is summarized, and various areas in which it has been proposed that the effect should be significant are discussed.

Newell, P. T.↗
NASA NTRS1992

Simulation study of interactions of Space Shuttle-generated electron beams with ambient plasmas

This report summarizes results obtained through the support of NASA Grant NAGW-1936. The objective of this report is to conduct large scale simulations of electron beams injected into space. The topics covered include the following: (1) simulation of radial expansion of an injected electron beam; (2) simulations of the active injections of electron beams; (3) parameter study of electron beam injection into an ionospheric plasma; and (4) magnetosheath-ionospheric plasma interactions in the cusp.

Lin, Chin S.↗
NASA NTRS2002

Alternatives to the ISS Plasma Contacting Units

A spacecraft in a high-density equatorial LEO plasma will float negative relative to the ambient plasma. Because of the electron collection of exposed conductors on its solar arrays, it may float negative by up to its array voltage. The floating potential depends on the relative areas of electron and ion collection of the spacecraft. Early estimates of the International Space Station (ISS) potential were about -140 V relative to the surrounding plasma, because of its 160 V solar array string voltage. Because of the possibility of arcing of ISS structures and astronaut EMUs (spacesuits) into the space plasma, Plasma Contacting Units (PCUs) were added to the ISS design, to reduce the highly negative floating potentials by emitting electrons (effectively increasing the ion collecting area). In addition to the now-operating ISS PCUs, safety rules require another independent arc-hazard control method. In this paper, I discuss alternatives to the ISS PCUs for keeping the ISS floating potential at values below the arc-thresholds of ISS and EMU surface materials. Advantages and disadvantages of all of the recline loss will be presented.

Ferguson, Dale C.↗
NASA NTRS1990

Theory of plasma contactors in ground-based experiments and low earth orbit

An examination of several models of electron collection by plasma contactors leads to a definition of the range of validity and applicability for each model. It is noted that most present ground-based experiments are of limited relevance to space applications of plasma contactors, since they operate in a regime where the magnetic field and effective collisions are at most only marginally important. An exception is the experiment of Stenzel and Urrutia (1986), which examined a plasma whose electron Larmor radius was small by comparison to the scale of the potential, and in which the anomalous transport of electrons across the magnetic field was important. The enhanced electron current was not continuous in time, but occurred in periodic bursts as the instabilities periodically emerged, saturated, and decayed.

Gerver, M. J.↗
NASA NTRS1972

Dielectric breakdown in a dilute plasma.

Description of tests performed to determine the effects of high voltages on dielectrics that are to insulate solar cell arrays operating at voltages up to 16 kV from the electrically active plasma of the space environment at 500 km altitude. The tests were performed on dielectrics considered for this application at positive bias voltages as high as 20 kV dc relative to ground in an argon plasma with electron number densities of approximately one million per cu cm. Teflon specimens displayed higher breakdown voltages than all other dielectrics tested.

Mckinzie, D. J., Jr.↗
DOE OSTI2024

Relativistic Alfvén Turbulence at Kinetic Scales

Abstract In a strongly magnetized, magnetically dominated relativistic plasma, Alfvénic turbulence can extend to scales much smaller than the particle inertial scales. It leads to an energy cascade somewhat analogous to inertial- or kinetic-Alfvén turbulent cascades existing in nonrelativistic space and astrophysical plasmas. Based on phenomenological modeling and particle-in-cell numerical simulations, we propose that the energy spectrum of such relativistic kinetic-scale Alfvénic turbulence is close to k −3 or slightly steeper than that due to intermittency corrections or Landau damping. We note the analogy of this spectrum with the Kraichnan spectrum corresponding to the enstrophy cascade in 2D incompressible fluid turbulence. Such turbulence strongly energizes particles in the direction parallel to the background magnetic field, leading to nearly one-dimensional particle momentum distributions. We find that these distributions have universal log-normal statistics.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1991

Plasma motions in planetary magnetospheres

Interplanetary space is pervaded by a supersonic 'solar wind' plasma; five planets, in addition to the earth, have magnetic fields of sufficient strength to form the cometlike cavities called 'magnetospheres'. Comparative studies of these structures have indicated the specific environmental factor that can result in dramatic differences in the behavior of any pair of magnetospheres. Although planetary magnetospheres are large enough to serve as laboratories for in situ study of cosmic plasma and magnetic field behavior effects on particle acceleration and EM emission, much work remains to be done toward relating magnetospheric physics results to the study of remote astrophysical plasmas.

Hill, T. W.↗
NASA NTRS1987

Megawatt level electric propulsion perspectives

For long range space missions, deliverable payload fraction is an inverse exponential function of the propellant exhaust velocity or specific impulse of the propulsion system. The exhaust velocity of chemical systems are limited by their combustion chemistry and heat transfer to a few km/s. Nuclear rockets may achieve double this range, but are still heat transfer limited and ponderous to develop. Various electric propulsion systems can achieve exhaust velocities in the 10 km/s range, at considerably lower thrust densities, but require an external electrical power source. A general overview is provided of the currently available electric propulsion systems from the perspective of their characteristics as a terminal load for space nuclear systems. A summary of the available electric propulsion options is shown and generally characterized in the power vs. exhaust velocity plot. There are 3 general classes of electric thruster devices: neutral gas heaters, plasma devices, and space charge limited electrostatic or ion thrusters.

Jahn, Robert G.↗
NASA NTRS1983

Ring and plasma - The enigmae of Enceladus

The E ring associated with the Kronian moon Enceladus has a lifetime of only a few thousand years against sputtering by slow corotating O ions. The existence of the ring implies the necessity for a continuous supply of matter. Possible particle source mechanisms on Enceladus include meteoroidal impact ejection and geysering. Estimates of ejection rates of particulate debris following small meteoroid impact are on the order of 3 x 10 to the -18th g/(sq cm sec), more than an order of magnitude too small to sustain the ring. A geyser source would need to generate a droplet supply at a rate of approximately 10 to the -16th g/(sq cm sec) in order to account for a stable ring. Enceladus and the ring particles also directly supply both plasma and vapor to space via sputtering. The absence of a 60 eV plasma at the Voyager 2 Enceladus L-shell crossing, such as might have been expected from sputtering, cannot be explained by absorption and moderation of plasma ions by ring particles, because the ring is too diffuse. Evidently, the effective sputtering yield in the vicinity of Enceladus is on the order of, or smaller than, 0.4, about an order of magnitude less than te calculated value. Small scale surface roughness may account for some of this discrepancy.

Haff, P. K.↗
NASA NTRS2023

Plasma Activated Water: A Technology for Acid Generation and Space Crop Production

As humanity returns to the moon and onward to Mars, sustainable space travel becomes essential for cost and independence from Earth. Astronaut activities in low Earth orbit resupply consumable materials and can require alternative technologies if transportation of chemicals is deemed hazardous. Plasma technology and applications are able to generate commodities that assist in achieving Earth independence. Plasma interaction with water generates acid in-situ using on-board resources of electricity and breathable air without the need for large infrastructure. At Kennedy Space Center, researchers have shown that plasma is able to produce nitric acid, and therefore nitrates, in a plant-usable form in water. In this report, the team presents results on acid generation in g/kW-hr as well as provides results on plasma activated water for plant growth assistance. Plasma was generated utilizing DC, AC, and pulsed power supplies in order to determine optimizing parameters for generation of this useful commodity.

Plasma↗
NASA NTRSDate not supplied

Plasma Activated Water: A Technology for Acid Generation and Space Crop Production

As humanity returns to the moon and onward to Mars, sustainable space travel becomes essential for cost and independence from Earth. Astronaut activities in low Earth orbit resupply consumable materials and can require alternative technologies if transportation of chemicals is deemed hazardous. Plasma technology and applications are able to generate commodities that assist in achieving Earth independence. Plasma interaction with water generates acid in-situ using on-board resources of electricity and breathable air without the need for large infrastructure. At Kennedy Space Center, researchers have shown that plasma is able to produce nitric acid, and therefore nitrates, in a plant-usable form in water. In this report, the team presents results on acid generation in g/kW-hr as well as provides results on plasma activated water for plant growth assistance. Plasma was generated utilizing DC, AC, and pulsed power supplies in order to determine optimizing parameters for generation of this useful commodity.

Plasma↗
NASA NTRS1995

Dynamic interactions between ionospheric plasma and spacecraft

Studies of the interactions between the Space Station Freedom and ionospheric plasma led to an improved understanding of the dynamics of these interactions. Some of the issues related to developing and sustaining arcs in ionospheric conditions are considered. A technique for the estimation of the amplitude and duration of arcs is presented. The technique uses the capacitance of the system to estimate the peak current and then uses the charge stored to estimate the arc duration. As new technologies are implemented on spacecraft, new environmental compatibility issues will arise. Some of the issues related to driving dielectric surfaces with alternating current voltages are considered. The steady state charging criteria is that over an oscillation, the ion charge collected is compensated for by the electron charge collected. This tends to drive the average potential negative so that the dielectric surface is positive for only a small portion of the cycle.

Snyder, David B.↗
DOE OSTI2023

Final Scientific Report on: Magnetized Shock Physics and Convergent Flows

The objective of this project was to study magnetized shocks in plasmas using the Omega Laser Facility to drive a solid foil into a magnetized gas, which would be preionized by the x-rays from the laser-solid interaction. The MIFEDS (magneto-inertial fusion electrical discharge system) provided the magnetic field. Magnetized shocks are of interest in magneto-inertial fusion, such as MagLIF and magnetized spherical implosions with both direct and indirect drive, space physics, heliophysics, and astrophysics. In magneto-inertial fusion the shocks of interest are collisional and perpendicular to the magnetic field lines, since the magnetic field needs to be compressed. In space, the shocks of interest are typically collisionless, due to the low plasma density, and both perpendicular and parallel to the magnetic field. The marginally collisionless regime between these is also of interest in both laboratory, fusion, and space plasmas, but has barely been investigated.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS2010

Advanced Space Fission Propulsion Systems

Fission has been considered for in-space propulsion since the 1940s. Nuclear Thermal Propulsion (NTP) systems underwent extensive development from 1955-1973, completing 20 full power ground tests and achieving specific impulses nearly twice that of the best chemical propulsion systems. Space fission power systems (which may eventually enable Nuclear Electric Propulsion) have been flown in space by both the United States and the Former Soviet Union. Fission is the most developed and understood of the nuclear propulsion options (e.g. fission, fusion, antimatter, etc.), and fission has enjoyed tremendous terrestrial success for nearly 7 decades. Current space nuclear research and technology efforts are focused on devising and developing first generation systems that are safe, reliable and affordable. For propulsion, the focus is on nuclear thermal rockets that build on technologies and systems developed and tested under the Rover/NERVA and related programs from the Apollo era. NTP Affordability is achieved through use of previously developed fuels and materials, modern analytical techniques and test strategies, and development of a small engine for ground and flight technology demonstration. Initial NTP systems will be capable of achieving an Isp of ~900 s at a relatively high thrust-to-weight ratio. The development and use of first generation space fission power and propulsion systems will provide new, game changing capabilities for NASA. In addition, development and use of these systems will provide the foundation for developing extremely advanced power and propulsion systems capable of routinely and affordably accessing any point in the solar system. The energy density of fissile fuel (8 x 10(exp 13) Joules/kg) is more than adequate for enabling extensive exploration and utilization of the solar system. For space fission propulsion systems, the key is converting the virtually unlimited energy of fission into thrust at the desired specific impulse and thrust-to-weight ratio. This presentation will discuss potential space fission propulsion options ranging from first generation systems to highly advanced systems. Ongoing research that shows promise for enabling second generation NTP systems with Isp greater than 1000 s will be discussed, as will the potential for liquid, gas, or plasma core systems. Space fission propulsion systems could also be used in conjunction with simple (water-based) propellant depots to enable routine, affordable missions to various destinations (e.g. moon, Mars, asteroids) once in-space infrastructure is sufficiently developed. As fuel and material technologies advance, very high performance Nuclear Electric Propulsion (NEP) systems may also become viable. These systems could enable sophisticated science missions, highly efficient cargo delivery, and human missions to numerous destinations. Commonalities between NTP, fission power systems, and NEP will be discussed.

Houts, Michael G.↗
DOE OSTI2022

Space flight associated changes in astronauts’ plasma-derived small extracellular vesicle microRNA: Biomarker identification

This pilot study suggests relatively short (median 12 days long) low-Earth orbit (LEO) spaceflight induces changes in circulating plasma small extracellular vesicle (sEV) microRNA expression. Normalization of small RNA sequencing (sRNAseq) data and quantitative polymerase chain reaction (qPCR) validation confirmed miR-4732-3p is significantly upregulated up to 3 days post-landing, and enrichment analysis suggests this miRNA is expressed in various central nervous system tissues and hematopoietic cells and may be linked to different organ disorders.

60 APPLIED LIFE SCIENCES↗