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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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NASA NTRS2012

The Rise and Fall of Star Formation Histories of Blue Galaxies at Redshifts 0.2 < z < 1.4

Popular cosmological scenarios predict that galaxies form hierarchically from the merger of many progenitor, each with their own unique star formation history (SFH). We use the approach recently developed by Pacifici et al. to constrain the SFHs of 4517 blue (presumably star-forming) galaxies with spectroscopic redshifts in the range O.2 < z < 1:4 from the All-Wavelength Extended Groth Strip International Survey (AEGIS). This consists in the Bayesian analysis of the observed galaxy spectral ' energy distributions with a comprehensive library of synthetic spectra assembled using state-of-the-art models of star formation and chemical enrichment histories, stellar population synthesis, nebular emission and attenuation by dust. We constrain the SFH of each galaxy in our sample by comparing the observed fluxes in the B, R,l and K(sub s) bands and rest-frame optical emission-line luminosities with those of one million model spectral energy distributions. We explore the dependence of the resulting SFH on galaxy stellar mass and redshift. We find that the average SFHs of high-mass galaxies rise and fall in a roughly symmetric bell-shaped manner, while those of low-mass galaxies rise progressively in time, consistent with the typically stronger activity of star formation in low-mass compared to high-mass galaxies. For galaxies of all masses, the star formation activity rises more rapidly at high than at low redshift. These findings imply that the standard approximation of exponentially declining SFHs wIdely used to interpret observed galaxy spectral energy distributions is not appropriate to constrain the physical parameters of star-forming galaxies at intermediate redshifts.

Pacifici, Camilla↗

NASA NTRS2013

Developing IVHM Requirements for Aerospace Systems

The term Integrated Vehicle Health Management (IVHM) describes a set of capabilities that enable sustainable and safe operation of components and subsystems within aerospace platforms. However, very little guidance exists for the systems engineering aspects of design with IVHM in mind. It is probably because of this that designers have to use knowledge picked up exclusively by experience rather than by established process. This motivated a group of leading IVHM practitioners within the aerospace industry under the aegis of SAE's HM-1 technical committee to author a document that hopes to give working engineers and program managers clear guidance on all the elements of IVHM that they need to consider before designing a system. This proposed recommended practice (ARP6883 [1]) will describe all the steps of requirements generation and management as it applies to IVHM systems, and demonstrate these with a "real-world" example related to designing a landing gear system. The team hopes that this paper and presentation will help start a dialog with the larger aerospace community and that the feedback can be used to improve the ARP and subsequently the practice of IVHM from a systems engineering point-of-view.

IVHM↗

NASA NTRS2014

Microstructure and Macrosegregation Study of Directionally Solidified Al-7Si Samples Processed Terrestrially and Aboard the International Space Station

This talk reports research that has been carried out under the aegis of NASA as part of a collaboration between ESA and NASA for solidification experiments on the International Space Station (ISS). The focus has been on the effect of convection on the microstructural evolution and macrosegregation in hypoeutectic Al‐Si alloys during directional solidification (DS). The DS‐experiments have been carried out under 1‐g at Cleveland State University (CSU) and under low‐g on the International Space Station (ISS). The thermal processing‐history of the experiments is well defined for both the terrestrially‐processed samples and the ISS‐processed samples. We have observed that the primary dendrite arm spacings of two samples grown in the low‐g environment of the ISS show good agreement with a dendrite‐growth model based on diffusion controlled growth. The gravity‐driven convection (i.e., thermosolutal convection) in terrestrially grown samples has the effect of decreasing the primary dendrite arm spacings and causes macrosgregation. In order to process DS‐samples aboard the ISS, dendritic‐seed crystals have to partially remelted in a stationary thermal gradient before the DS is carried out. Microstructural changes and macrosegregation effects during this period are described.

Angart, Samuel↗

NASA NTRS2014

Comparison of Directionally Solidified Samples Solidified Terrestrially and Aboard the International Space Station

This article reports research that has been carried out under the aegis of NASA as part of a collaboration between ESA and NASA for solidification experiments on the International Space Station (ISS). The focus has been on the effect of convection on the microstructural evolution and macrosegregation in hypoeutectic Al-Si alloys during directional solidification (DS). Terrestrial DS-experiments have been carried out at Cleveland State University (CSU) and under microgravity on the International Space Station (ISS). The thermal processing-history of the experiments is well defined for both the terrestrially processed samples and the ISS-processed samples. As of this writing, two dendritic metrics was measured: primary dendrite arm spacings and primary dendrite trunk diameters. We have observed that these dendrite-metrics of two samples grown in the microgravity environment show good agreements with models based on diffusion controlled growth and diffusion controlled ripening, respectively. The gravity-driven convection (i.e., thermosolutal convection) in terrestrially grown samples has the effect of decreasing the primary dendrite arm spacings and causes macrosegregation. Dendrite trunk diameters also show differences between the earth- and space-grown samples. In order to process DS-samples aboard the ISS, the dendritic seed crystals were partially remelted in a stationary thermal gradient before the DS was carried out. Microstructural changes and macrosegregation effects during this period are described and have modeled.

Angart, S.↗

NASA NTRS2010

MOS 2.0: The Next Generation in Mission Operations Systems

A Mission Operations System (MOS) or Ground System constitutes that portion of an overall space mission Enterprise that resides here on Earth. Over the past two decades, technological innovations in computing and software technologies have allowed an MOS to support ever more complex missions while consuming a decreasing fraction of Project development budgets. Despite (or perhaps, because of) such successes, it is routine to hear concerns about the cost of MOS development. At the same time, demand continues for Ground Systems which will plan more spacecraft activities with fewer commanding errors, provide scientists and engineers with more autonomous functionality, process and manage larger and more complex data more quickly, all while requiring fewer people to develop, deploy, operate and maintain them. One successful approach to such concerns over this period is a multimission approach, based on the reuse of portions (most often software) developed and used in previous missions. The Advanced Multi-Mission Operations System (AMMOS), developed for deep-space science missions, is one successful example of such an approach. Like many computing-intensive systems, it has grown up in a near-organic fashion from a relatively simple set of tools into a complexly interrelated set of capabilities. Such systems, like a city lacking any concept of urban planning, can and will grow in ways that are neither efficient nor particularly easy to sustain. To meet the growing demands and unyielding constraints placed on ground systems, a new approach is necessary. Under the aegis of a multi-year effort to revitalize the AMMOS's multimission operations capabilities, we are utilizing modern practices in systems architecting and model-based engineering to create the next step in Ground Systems: MOS 2.0. In this paper we outline our work (ongoing and planned) to architect and design a multimission MOS 2.0, describe our goals and measureable objectives, and discuss some of the benefits that this top-down, architectural approach holds for creating a more flexible and capable MOS for Missions while holding the line on cost.

ground systems↗

NASA NTRS2015

Planetary Protection Knowledge Gaps for Human Extraterrestrial Missions Workshop Booklet - 2015

Although NASA's preparations for the Apollo lunar missions had only a limited time to consider issues associated with the protection of the Moon from biological contamination and the quarantine of the astronauts returning to Earth, they learned many valuable lessons (both positive and negative) in the process. As such, those efforts represent the baseline of planetary protection preparations for sending humans to Mars. Neither the post-Apollo experience or the Shuttle and other follow-on missions of either the US or Russian human spaceflight programs could add many additional insights to that baseline. Current mission designers have had the intervening four decades for their consideration, and in that time there has been much learned about human-associated microbes, about Mars, and about humans in space that has helped prepare us for a broad spectrum of considerations regarding potential biological contamination in human Mars missions and how to control it. This paper will review the approaches used in getting this far, and highlight some implications of this history for the future development of planetary protection provisions for human missions to Mars. The role of NASA and ESA's planetary protection offices, and the aegis of COSPAR have been particularly important in the ongoing process.

Fonda, Mark L.↗

NASA NTRSDate not supplied

Work Function Matching Passive Lunar Dust Mitigation Coating Preparation for Lunar Flight Opportunity

With the Artemis program, NASA isplanning longer stays on the surface, with more activities that have the potential to put the astronauts and equipment in contact with greater quantities of lunar dust. The success of these missions will depend on our understanding of material interactions with lunar dust and the development of ways to mitigate dust effects. This is particularly truein cases where exposure to dust will lead to failure of components, unacceptable loss of power or thermal control, unacceptable loss of visibility, or health issues.Optically transparent, sputter deposited,work function matching coatings are being developed at NASA Glenn Research Center to reduce adhesion of dust to windows, lenses and display panels by matching the minimum energy to remove an electron from the surface to that oflunar dust in order to reduce adhesion due to charge transfer. One of these work function matching coatings will be tested as part of Aegis Aerospace Inc.’s Regolith Adherence Characterization experiment going to the lunar surface on a Commercial Lunar Payload Services (CLPS) lander in 2023. Preparation of the work function matching coating and initial characterization prior to delivery for flight integration will be discussed.

Lunar dust, passive mitigation, CLPS demonstration↗

NASA NTRSDate not supplied

Exposure of Plant Seeds to the Space Environment outside the International Space Station

If crop seeds are to be stored on space vehicles for long-duration missions, the effects of the space environment on the seeds must be understood for developing mitigation strategies to prevent seed degradation. The MISSE-Seed project was designed to investigate the effects of space exposure on seed quality and storage. The project also tested the Materials International Space Station Experiment (MISSE) platform for exposing biological samples to the space environment and evaluated the capability of a newly designed passive sample containment vessel for the provision of acceptable storage conditions for seeds, or other biological samples, to be preserved upon exposure to the space environment outside the ISS. The experiment was launched to the ISS on NG-15and returned to Earth aboard SpX-24. The specimens consisted of eleven seed varieties (Lettuce, Scarlet Frills, Amara, Garnet Giant, Pac Choi, Radish, Mizuna, Tomato, Cauliflower, Pepper, and Arabidopsis). The exposure lasted eight months outside the ISS in the MISSE hardware at the Zenith position. Data-loggers and thermoluminescent dosimeters (TLDs) were included in each container to record the environmental data. Temperature profiles and radiation/UV exposure data were also provided by Aegis Aerospace, the MISSE Implementation Partner. In this presentation, the hardware and experimental design, the environmental profiles, and the results of post-flight germination tests will be presented.

Jeffrey T Richards↗

NASA NTRSDate not supplied

Exposure of Plant Seeds to the Space Environment Outside the International Space Station

Jeffrey T Richards↗

NASA NTRS2022

Formal Methods for Trusted Space Autonomy, Boon or Bane?

Trusted Space Autonomy is challenging in that space systems are complex artifacts deployed in a high stakes environment with complicated operational settings. Thus far these challenges have been met using the full arsenal of tools: formal methods, informal methods, testing, runtime techniques, and operations processes. Using examples from previous deployments of autonomy to the Remote Agent on DS-1, Autonomous Sciencecraft on EO-1, WATCH on MER, IPEX, AEGIS on MER, MSL, and M2020, and the M2020 Onboard planner, we discuss how each of these approaches have been used to enable successful deployment of autonomy. We next focus on relatively limited use of formal methods (both prior to deployment and runtime methods). From the needs perspective, formal methods represent the best chance for reliable autonomy as testing, informal methods, and operations accommodations do not scale well with increasing complexity of the autonomous system. However from the practice perspective, formal methods have been limited in their application due to difficulty in eliciting formal specifications and challenges in representing complex constraints such as metric time and resources. We discuss some of these challenges as well as the opportunity to extend formal and informal methods into runtime validation systems.

Chien, Steve↗

NASA NTRSDate not supplied

Exposure of Plant Seeds to the Space Environment Outside the International Space Station

Crop seeds may prove to be a vital component of future long-term spaceflight missions, and the impacts of extended exposure on seed degradation is not well understood. The MISSE-Seed project was designed to investigate the effects of space exposure on seed quality and storage. The project also served as a test of biological materials aboard the Materials International Space Station Experiment (MISSE) platform, and evaluated the capability of a newly designed passive sample containment vessel for the provision of acceptable storage conditions for seed and other biological samples to be preserved upon exposure to the space environment outside the ISS. MISSE-Seed was launched to the ISS on NG-15 in July of 2021 and returned to Earth aboard SpX-24 after approximately 8 months of exposure to the space environment. The specimens consisted of eleven seed varieties (Lettuce, Scarlet Frills, Amara, Garnet Giant, Pac Choi, Radish, Mizuna, Tomato, Cauliflower, Pepper, and Arabidopsis). Data-loggers and thermoluminescent dosimeters (TLDs) were included in each container to record environmental data. Temperature profiles and radiation/UV exposure data were also provided by Aegis Aerospace, the MISSE Implementation Partner. Hardware and experimental design, environmental profiles, and post-flight germination and growth results will be presented.

Alexander D Meyers↗

NASA NTRS2024

Space Environmental Exposure of the MISSE 9-15 Polymers and Composites Experiment 1-4 (PCE 1-4)

Spacecraft in low Earth orbit (LEO) are subjected to harsh environmental conditions, including radiation (cosmic rays, ultraviolet (UV), x-ray and charged particle radiation), micrometeoroids and orbital debris, temperature extremes, thermal cycling, and atomic oxygen (AO). These environmental exposures can result in erosion, embrittlement and optical property degradation of susceptible materials threatening spacecraft performance and durability. To increase our understanding of effects such as AO erosion and radiation induced embrittlement of spacecraft materials, NASA Glenn Research Center has developed a series of experiments that were flown as part of the Materials International Space Station Experiment (MISSE) missions on the exterior of the International Space Station (ISS). These experiments have provided critical space environmental durability data such as AO erosion data of polymers and composites, and radiation induced mechanical property degradation of spacecraft insulation materials, after long term space exposure. Recently, four Glenn experiments with 365 flight samples were flown on ISS’s MISSE-Flight Facility (MISSE-FF). These experiments are the Polymers and Composites Experiment-1 (PCE-1) flown as part of the MISSE-9 mission, the PCE-2 flown as part of the MISSE-10 mission, the PCE-3 flown as part of the MISSE-12 and MISSE-15 missions, and the PCE-4 flown as part of the MISSE-13 mission. This paper provides details on the space environment exposure of Glenn’s PCE 1-4 flight samples. Passive samples were flown in each flight orientation for post-flight AO fluence determination and on-orbit contamination analyses. Solar exposure estimates were computed by Aegis Aerospace, Inc. The environment exposure details include the total space vacuum duration, time on the MISSE-FF, the direct space exposure duration, the AO fluence and the computed mission Equivalent Sun Hours (ESH) solar exposure. Typical on-orbit temperatures are also provided along with a summary of analyses of PCE 1-4 contamination witness samples. Knowledge of the space environmental exposure of the PCE 1-4 flight samples is crucial for flight data interpretation.

Atomic oxygen↗

NASA NTRSDate not supplied

Engineering the Interface: Advanced Surface Technologies for Lunar Dust Management and Equipment Longevity

Through the Artemis program, NASA intends to develop a sustainable human foothold on the Moon, ultimately paving the way for crewed exploration of Mars. The Moon's hostile environment poses numerous obstacles, including exposure to radiation, temperature extremes, micrometeoroid threats, and particularly the persistent problem of lunar dust. Lunar dust impacts nearly every aspect of surface operations through adhesion and abrasion mechanisms, with contamination from anthropogenic activities (landing, rovers) far outweighing natural phenomena. Multiple adhesion pathways contribute to surface contamination in the lunar environment, including van der Waals forces, electrostatic forces, chemical reaction, and magnetic forces from elemental iron deposits. Sharp asperities from micrometeoroid bombardment and atmospheric absence increase interaction potential and enable mechanical interlocking. Low cohesion between dust particles exacerbates these challenges, as minimal interaction potential between dust and nearby surfaces overcomes particle cohesion, causing contamination. Lunar dust adhesion mitigation technologies can be categorized as either active, requiring external energy, or passive, relying on intrinsic material properties. Ultrasonic and electrodynamic technologies have been developed to the highest technology readiness level for active approaches. Passive strategies primarily focus on surface chemistry and topography modifications. At NASA Langley Research Center, approaches include surface migration agents to reduce surface energy, topographical modification using laser ablation patterning, and tailored surface conductivity to reduce intrinsic adhesion force. Performance has been evaluated using custom-built ultrasonic and centrifuge instruments. Plume-surface interactions from lunar landers can propel micrometer-sized particles at velocities up to 1000 m s-1.8 These particles pose risks to landers, habitats and infrastructure, leading to erosion, degradation, and reduced component lifespan. A panel recovered from Surveyor III was determined to have been severely abraded because of lunar dust displaced from the Apollo 12 lunar module that landed 160 m away. The performance of metallic surfaces has been evaluated via high velocity single particle impact using the laser-induced project impact test (LIPIT) facility at the University of Utah. Peridynamics modeling, a form of continuum mechanics that uses a nonlocal approach enabling greater simulation capabilities of crack initiation and fracture, has also been utilized to gain greater insight into material response during impact events. Lunar dust contamination challenges extend to power generation systems and moving equipment. Cables, rotation stages, and other mechanisms may experience limited range of motion and reduced lifetime due to dust infiltration. NASA Langley Research Center has evaluated traditional aerospace alloys, softgoods, wear resistant ceramics, and several polymer and polymer composite materials. Test methods have included traditional techniques like Taber abrasion testing, as well as designed test configurations developed in the DUSTE (dust, ultraviolet radiation, and space thermal environmental) chamber that reproduce mechanism functions in operational environment. Beyond laboratory experiments, several flight experiments have been conducted. Materials were exposed to the low Earth orbit environment on the Materials International Space Station Experiment (MISSE) and to the lunar surface environment through the Aegis Aerospace Regolith Adherence Characterization (RAC) payload and the Honeybee Robotics PlanetVac payload. Determining lunar dust's impact on surface exploration and habitation requires comprehensive experimental and computational capabilities combined with lessons learned from initial lunar activities. Identifying the greatest environmental challenges and developing mitigation technologies provides the clearest path toward successfully, expeditiously, and efficaciously completing NASA's mission. This presentation will discuss ongoing efforts at NASA Langley Research Center and collaborator contributions to these critical objectives.

Surface Engineering↗

NASA NTRSDate not supplied

Exposure of Highly Reflective Far-Ultraviolet Coatings to LEO Environment for TRL Advancement for the Habitable Worlds Observatory

Over the past several years, our team at the NASA Goddard Space Flight Center (GSFC), in collaboration with the Jet Propulsion Laboratory (JPL) and the Naval Research Laboratory (NRL), have developed several new protected Al coating technologies with improved Far-Ultraviolet (FUV) reflectance performance and more robust environmental stability. These include Al protected with lithium-based fluoride (LiF) coatings such as hot deposited LiF (eLiF), XeF 2 -passivated LiF coatings (XeLiF), Li 3 AlF 6 overcoats, AlF 3 (plasma passivated), and XeF 2 passivated MgF 2 coatings (XeMgF 2 ). However, despite these developments, relatively little experimental information exists regarding the long-term stability of these coatings after simultaneous exposure to the Low Earth Orbit (LEO) environment. To evaluate their environmental durability and advance their Technology Readiness Level (TRL), representative samples of these coating technologies, Al+XeLiF, Al+eLiF, Al+Li 3 AlF 6 , Al+AlF 3 , Al+XeMgF 2 , and bare Al as reference samples, were flown onboard the International Space Station (ISS) as part of the Materials International Space Station Experiment 20 (MISSE-20). The MISSE platform is operated by Aegis Aerospace for relatively long-duration (e.g. 6 months) external exposure experiments in a space environment. The coatings were deposited on ULE and Zerodur substrates, and witness samples deposited on the same coatings runs, but on glass slides were left on Earth as control. A subset of the flight samples were fitted with MgF 2 windows to reduce direct exposure to atomic oxygen (AO) and charged particles, and still let through UV and other types of radiation on these samples. After approximately 6 months of exposure in the forward-facing (RAM) direction, the samples were returned to Earth and characterized by performing FUV/NUV/VIS/NIR reflectance measurements to quantify degradation, spectroscopic ellipsometry to evaluate coating thickness and optical constants, atomic force microscopy (AFM) to quantify surface roughness evolution during the flight in the ISS. The MgF 2 protective windows were also analyzed through FUV transmission measurements. Comparison with the witness samples left on the ground and with the flown bare Al samples (with just the naturally occurring Al 2 O 3 layer) provided a quantitative assessment of coating thickness variations, optical performance degradation, and morphological changes induced by prolonged exposure to the LEO environment.

Far Ultraviolet (FUV)↗

DOE OSTI2023

Flexible Gasification of Coal and Biomass to Generate Carbon Free Electric Power and Hydrogen

This paper describes the development of a coal and biomass-fed plant concept to co-produce electric power and hydrogen with net-negative CO2 emissions under the aegis of the 21st Century Power Plant initiative of the U.S. Department of Energy (DOE), whose goal is to advance innovative power plant concepts that are capable of flexible, net-zero carbon emission operations while producing cost-effective “blue” hydrogen to support economy-wide decarbonization goals. The proposed standalone plant will be in Nebraska, USA. The specified design feedstock is a hybrid blend of Powder River Basin (PRB) subbituminous coal from Wyoming and local Nebraska biomass (corn stover), 50 wt.% each (dry basis). Other potential feedstocks, including woody biomass (eastern red cedar) and waste plastic (auto shredder residue) were evaluated or reviewed as alternates. The proposed process block comprises a high-pressure, oxygen-blown fluidized bed gasifier (GTI Energy U-GAS® process) coupled with water gas shift, the Selexol process for acid gas (H2S and CO2) removal, and pressure-swing adsorption (PSA) to yield 8,500 kg/h of high-purity hydrogen. The off gas from the PSA unit is used in the power block (gas turbine combined cycle) to generate electric power to support the gasification process, hydrogen production, and 50 MWe net electric power to the grid. All major plant equipment including the gasifier, gas cleanup system, and power generation are commercially available and proven in other applications and considered at TRL 8-9. However, gasification of corn stover biomass is considered at TRL 6. Overall thermal efficiency of the plant is 50% (net HHV) with net atmospheric CO2 removal at a rate of 250-300,000 tpa. Design activities necessary to provide input to a FEED study (Phase II of the project), including the development of the Environmental Information Volume (EIV) for the host site, and an investment case, based on a pro-forma pre-FEED level cost estimate, have been completed and are described in detail in this paper.

Gülen, S. Can↗