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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 1,189 records · Page 66
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NASA NTRS2020

Validation of SAGE III/ISS Solar Ozone Data with Correlative Satellite and Ground Based Measurements

The Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) was launched on February 19, 2017 and began routine operation in June 2017. The first two years of SAGE III/ISS (v5.1) solar ozone data were evaluated by using correlative satellite and ground-based measurements. Among the three (MES, AO3, and MLR) SAGE III/ISS solar ozone products, AO3 ozone shows the best accuracy and precision, with mean biases less than 5% for altitudes ~15–55 km in the mid-latitudes and ~20–55 km in the tropics. In the lower stratosphere and upper troposphere, AO3 ozone shows high biases that increase with decreasing altitudes and reach ~10% near the tropopause. Preliminary studies indicate that those high biases primarily result from the contributions of the oxygen dimer (O4) not being appropriately removed within the ozone channel. The precision of AO3 ozone is estimated to be ~3% for altitudes between 20 and 40 km. It degrades to ~10–15% in the lower mesosphere (~55 km), and ~20–30% near the tropopause. There could be an altitude registration error of ~100 meter in the SAGE III/ISS auxiliary temperature and pressure profiles. This, however, does not affect retrieved ozone profiles in native number density on geometric altitude coordinates. In the upper stratosphere and lower mesosphere (~40–55 km) the SAGE III/ISS (and SAGE II) sunset ozone values are systematically higher than sunrise data by ~5–8% which are almost twice larger than what observed by other satellites or model predictions. This feature needs further study.

H J Wang↗
NASA NTRS2014

TPSAS-NF1676L-17844-DND

Distributed propulsion is being proposed as an approach to achieve greater aircraft efficiency. An added benefit which might be realized with a distributed propulsion configuration is a reduction in radiated sound power. A reduction in radiated sound power could relieve concerns related to an increase in community noise that would accompany the adaptation of a fleet of many small aircraft fielded to meet increased travel demand. However, a reduction in radiated sound power does not necessarily translate into community acceptance of the new noise signature. Some characteristics of distributed propulsion configurations can create aural effects that people would find more annoying even though the sound is at a lower power level. To understand the community response to the new class of noise that a distributed propulsion system would present requires the prediction, synthesis and auralization of the noise in a controlled environment. Representative members of the community can then be exposed to the noise and queried for their reaction. These are the types of tests performed in NASA Langley’s Exterior Effects Room. This report summarizes preliminary results obtained using isolated propeller predictions. The sound pressure level of a single ‘large’ propeller is compared to that of two ‘smaller’ propellers of equivalent total thrust. The aural effects of different implementations of the two propellers are also considered. The different implementations include rotation direction and blade passage frequency separation.

Dan Palumbo↗
NASA NTRS2020

Oxygen and carbon stable isotope composition of the weathering Mg-carbonates on the surface of the LEW 85320 ordinary chondrite: Revisited

New δ13C and δ18O values were measured to constrain the formation mechanisms of two previously identified generations (Antarctica and Houston) of terrestrial weathering carbonates, nesquehonite, which formed on the surface of the Lewis Cliff 85320 ordinary chondrite. These two nesquehonite generations exhibit a characteristic carbon and oxygen isotopic trend which starts with a linear δ13C-δ18O covariation followed by a continuous increase in δ18O with little to no change in δ13C. Based upon the newly developed nesquehonite-water oxygen isotope thermometry and the measured δ18O value of melted ice from Antarctica, the formation temperature of the Antarctic nesquehonite generation was estimated to be -1.9 ± 3℃. Houston nesquehonite generation was most likely formed from an evaporative residue of the melted Antarctic ice at 30 ± 4℃. Modeling the isotopic trend of the two generations suggests that evaporation created large δ18O variations in the nesquehonite while carbon isotopes were stabilized by exchange between the parent liquid and atmospheric CO2. Thus, we suggest that carbonates formed by terrestrial weathering in Antarctica should possess a widespread in δ18O values and a narrow range in δ13C values under dry and cold conditions. Finally, the observed wide spread of δ18O in Martian carbonates (e.g., Allan Hills 84001 and Nakhla) can be explained by evaporation near 0℃ and may have formed by a similar mechanism to that of the nesquehonite in the LEW 85320. Meanwhile, the wide spread of δ13C suggests that two carbon reservoirs with distinct isotope compositions on Mars (e.g., the atmospheric carbon and magmatic carbon) may be actively participating in the formation process.

weathering↗
NASA NTRSDate not supplied

Understanding the Impact of High-Velocity Dust Due to Lunar Landings

Evidence from earlier landings by Surveyor and Apollo have provided ample evidence regarding the dangers of high-velocity ejecta. These dangers include the generation of dust that settle on equipment, posing a hazard to equipment fol-lowing landing, the sandblasting of objects near the landing site, and the spead of high-velocity dust over the entire lunar surface and in lunar orbit that may remain for long periods of time. Recent work has provided valuable insight into the behavior and nature of the dust as a function of lander size, but further work is needed to gain a better understanding of the initial trajectories of this high- velocity dust.

lunar↗
NASA NTRS2020

Encealdus Orbilander: A Flagship Mission Concept for Astrobiology

"Whether life exists beyond Earth remains a fundamental question driving our exploration of the Solar System. At Saturn’s moon Enceladus, plumes of oceanic material vented into space allow the investigation of the astrobiological potential of an ocean world, hinted at by Cassini, without the necessity of drilling through kilometers of ice crust. The Enceladus Orbilander is a flagship ($2.56B in fiscal year 2025 dollars) mission concept created for the 2023–2033 Planetary Science Decadal Survey. Orbilander takes full advantage of the opportunity provided by Enceladus’ plumes to search for signs of life. A single spacecraft both orbits and lands, capturing samples from four distinct reservoirs offered by the plumes. These samples, both particulate and vapor, are then analyzed by the Life Detection Suite (LDS), a set of five instruments conducting complementary and orthogonal biosignature-seeking measurements. To provide the context that specifically enhances interpretation of LDS measurements, geochemical and geophysical investigations are conducted both in orbit and on the surface. These reveal the physio-chemical state of the ocean and core as well as the processes involved in ejection of plume material and how these affect the ocean material analyzed by the LDS. The Orbilander can be delivered to the Saturn system via several launch vehicle and trajectory options, including a direct trajectory (7-year cruise), a ∆V-EGA trajectory (9-year cruise) and several options using an inner cruise with Venus and Earth flybys (10-year cruise). Upon Saturn Orbit Insertion, a 4-year moon tour pumps down the Orbilander’s orbit to intercept Enceladus. The most optimal arrival times balance the Jupiter flyby opportunities of the late 2030s and solar illumination at the Enceladus high southern latitudes where plume material is most abundant. This mission concept therefore targets project start in 2030. Upon Enceladus Orbit Insertion, the Orbilander begins a 1.5-year-long campaign of landing site reconnaissance, remote sensing science, and collecting sufficient plume sample to run all but one of the LDS measurements. After successful landing, the Orbilander spends 2 years on the surface conducting multiple LDS measurements with all five instruments on actively and passively collected plume material, as well as seismic investigations. The schedule laid out here is well-defined, but the mission also has operational and resource flexibility should additional reconnaissance be needed. As part of the design study, mission and development risks were identified and mitigation strategies proposed. Technologies key to achieving the life detection science objectives include instrumentation matured under programs like COLDTech and ICEE-2, such as aspects of the sampling system and microfluidic devices, as well as well-known techniques like high-resolution and separation-capable mass spectrometers. Autonomous onboard navigation is planned to maintain a halo orbit around Enceladus to enable passive sampling from orbit as well as reconnaissance measurements for use in site selection and landing. Terrain relative navigation is included to ensure safe landing, given that targeted areas may contain landing hazards. Continued development of radioisotope thermoelectric generator (RTG) technology and long-life batteries is essential for this long duration mission. The Enceladus Orbilander represents an optimal point in the trade space of science value versus cost, taking advantage of the extensive knowledge of Enceladus provided by Cassini, how well Enceladus lends itself to a search for life in material from its ocean, and the flexibility afforded by the innovative design developed by the APL team. By taking full advantage of Enceladus’ plumes both in orbit and on the surface, Orbilander represents a robust search for life with complementary and orthogonal biosignatures as well as contextual geophysical and geochemical measurements, determining not only whether Enceladus is inhabited (at levels up to 500,000× scarcer than in Earth’s oceans) but also why. "

Exobiology↗
NASA NTRSDate not supplied

Usage-Based Discovery of Earth Observations

Most providers of Earth Observation data enable search via dataset characteristics, (e.g., quantity being measured, instrument, location, and time). However, the Earth Science Information Partners Federation (ESIP) is attempting to improve dataset discovery by capturing information on how datasets are used. At a usage-based discovery hackfest at the July 2020 ESIP Summer Meeting, participants pooled their collective skills to implement a prototype based on the connections between datasets and data usage, which can reveal unanticipated patterns in dataset connectivity that are not apparent through traditional approaches. A survey of natural hazards websites, focusing on hydrology-related hazards such as floods and hydrology datasets such as rainfall, illustrated the difficulty of gleaning which dataset was actually used and how it was accessed. This difficulty highlights the need for greater transparency on dataset usage in website design. An application wireframe for a usage-based discovery database was conceptualized as a tool to help applications data specialists rapidly assemble a fit-for-purpose website as part of a disaster response, where customer feedback was integral to the manner in which the website would be developed and delivered. Capturing connections among datasets and instances of usage, either for research or applications, could help users identify datasets with a proven track record of utility or those that have been supplanted by more accurate and(or) precise representations. It may also help Earth Observation providers maximize returns on investments in data services. Social discovery, i.e, following discovery paths laid down by previous users of the data, could be a critical tool for improving the timeliness and applicability of dataset delivery at times and in circumstances where practitioners don’t have the capacity to evaluate the deluge of datasets that are returned by today’s search tools.

search↗
NASA NTRS2020

Microwave Sintering Lunar Landing Pads & Horizontal Infrastructure

Moon to Mars Planetary Autonomous Construction Technology’s (MMPACT) Microwave Structure Construction Capability (MSCC) team is developing the ability to prepare the lunar regolith and densify it into glass-ceramic landing pads and horizontal infrastructure. Microwave energy will be utilized to densify the lunar regolith. Some of the concept of operations, simulant and synthetic minerals, site preparation, design, microwave sintering, testing, & ancillary instrument technical challenges were listed. A current status of the MSCC project is also provided.

Microwave, sintering, lunar, regolith, landing pad↗
NASA NTRSDate not supplied

Fluid Shifts Study

Explore the source record for details and available documents.

Steven Laurie↗
NASA NTRS2019

Cold Survivable Distributed Motor Controller (CSDMC)

This paper presents the results of NASA’s COLDTECH development entitled “Cold Survivable Distributed Motor Controller (CSDMC)”. This work addresses the need to lower the mass, power and volume of the motor control electronics and its associated cabling. Landed payload mass of ocean world missions typically requires a spacecraft launch mass of 7-10x the landed mass due to the required propellant to get the payload to the surface. Reduction of landed mass leads to cheaper, more frequent missions and/or increased science return. This work addresses this need by developing a distributed electronics architecture, which places control and power electronics near or at actuators and instruments. The outcome of this effort will result in a 10X reduction in harness mass, enabling a significant increase in science payload which then enables more capable sample acquisition, delivery and analysis systems on these missions. Placing the control and power conversion electronics at or near the actuators or instruments is the cornerstone of our distributed architecture. To do this, we developed the technology necessary to distribute the electronics and place them on a shared interface and power bus. This enables a significant reduction in cable mass along with its associated complexity. This allows spacecraft designers to take advantage of volume at the extremities that would normally not be utilized. In this paper we discuss the technologies and system design to achieve these goals in support of ocean world missions. These technologies include the development of our motor control modules, a point of load regulator and isolated converter modules along with the packaging technology necessary to allow our electronics to survive the extreme temperatures.

Stell, Chris↗