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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS2014

LADEE UVS (UltraViolet Visible Spectrometer) and the Search for Lunar Exospheric Dust: A Detailed Spectral Analysis

The Lunar Atmosphere and Dust Environment Explorer (LADEE) executed science observations in lunar orbit spanning 2013-Oct-16- 2014-04-18 UT. LADEE's Ultraviolet/Visible Spectrometer (UVS) studies the composition and temporal variations of the tenuous lunar exosphere and dust environment, utilizing two sets of optics: a limb-viewing telescope, and a solar-viewer. The limb-viewing telescope observes illuminated dust and emitting gas species while the Sun is just behind the lunar limb. The solar viewer, with its diffuser, allows UVS to also stare directly at the solar disk as it approaches the limb, sampling progressively lower exosphere altitudes. Solar viewer "Occultation" activities occur at the lunar sunrise limb, as the LADEE spacecraft passes into the lunar night side, facing the Sun (the spacecraft orbit is near-equatorial retrograde). A loss of transmission of sunlight occurs by the occultation of dust grains along the line-of-sight. So-called "Inertial Limb" activities have the limb-viewing telescope pointed at the lit exosphere just after the Sun has set. Inertial Limb activities follow a similar progression of diminishing sampling altitudes but hold the solar elongation angle constant so the zodiacal light contribution remains constant while seeking to observe the weak lunar horizon glow. On the dark side of the moon, "Sodium Tail" activities pointed the limb-viewing telescope in the direction of the Moon's sodium tail (similar to anti-sunward), during different lunar phases. Of the UVS data sets, these show the largest excess of scattered blue light, indicative of the presence of small (approximately 100 nm) dust grains in the tail. Correlations are sought between dust in the sodium tail and meteor streams and magnetotail crossings to investigate impact- versus electrostatic-lofting. Once lofted, nanoparticles can become charged and picked up by the solar wind. The LADEE UVS Occultation, Inertial Limb, and Sodium Tail spectral datasets provide evidence of a lunar dust exosphere.

LADEE↗
NASA NTRS2019

Coronagraphic Observations of the Lunar Sodium Exosphere January-June, 2017

In order to observe the lunar sodium exosphere out to one-half degree around the Moon, we designed, built and installed a small robotically controlled coronagraph at the Winer Observatory in Sonoita, Arizona. Observations are obtained remotely every available clear night from our home base at Goddard Space Flight Centeror from Prescott, Arizona. We employ an Andover temperature-controlled 1.5 Å wide narrow-band filter centered on the sodium D2line, and a similar 1.5 Å filter centered blueward of the D2line by 3Åfor continuum observations. Our data encompass lunations in 2015, 2016, and 2017, thus we have a long baseline of sodium exospheric calibrated images. During the course of three years we have refined the observational sequence in many respects. Therefore this paper only presents the results of the spring, 2017, observing season. We present limb profiles from the south pole to the north pole for many lunar phases.Our data do not fit any power of cosine model as a function of lunar phase or with latitude. The extended Na exosphere has a characteristic temperature of about 2250 -6750 K, indicative of a partially escaping exosphere. The hot escaping component may be indicative of a mixture of impact vaporization and a sputtered component.

Lunar exosphere composition↗
NASA NTRS2009

Sources of Sodium in the Lunar Exosphere: Modeling Using Ground-Based Observations of Sodium Emission and Spacecraft Data of the Plasma

Observations of the equatorial lunar sodium emission are examined to quantify the effect of precipitating ions on source rates for the Moon's exospheric volatile species. Using a model of exospheric sodium transport under lunar gravity forces, the measured emission intensity is normalized to a constant lunar phase angle to minimize the effect of different viewing geometries. Daily averages of the solar Lyman alpha flux and ion flux are used as the input variables for photon-stimulated desorption (PSD) and ion sputtering, respectively, while impact vaporization due to the micrometeoritic influx is assumed constant. Additionally, a proxy term proportional to both the Lyman alpha and to the ion flux is introduced to assess the importance of ion-enhanced diffusion and/or chemical sputtering. The combination of particle transport and constrained regression models demonstrates that, assuming sputtering yields that are typical of protons incident on lunar soils, the primary effect of ion impact on the surface of the Moon is not direct sputtering but rather an enhancement of the PSD efficiency. It is inferred that the ion-induced effects must double the PSD efficiency for flux typical of the solar wind at 1 AU. The enhancement in relative efficiency of PSD due to the bombardment of the lunar surface by the plasma sheet ions during passages through the Earth's magnetotail is shown to be approximately two times higher than when it is due to solar wind ions. This leads to the conclusion that the priming of the surface is more efficiently carried out by the energetic plasma sheet ions.

Sarantos, Menelaos↗
NASA NTRS2014

Contingency Trajectory Design for a Lunar Orbit Insertion Maneuver Failure by the Lunar Atmosphere Dust Environment Explorer (LADEE) Spacecraft

The purpose of this extended abstract is to present results from a failed lunar-orbit insertion (LOI) maneuver contingency analysis for the Lunar Atmosphere Dust Environment Explorer (LADEE) mission, managed and operated by NASA Ames Research Center in Moffett Field, CA. The LADEE spacecrafts nominal trajectory implemented multiple sub-lunar phasing orbits centered at Earth before eventually reaching the Moon (Fig. 1) where a critical LOI maneuver was to be performed [1,2,3]. If this LOI was missed, the LADEE spacecraft would be on an Earth-escape trajectory, bound for heliocentric space. Although a partial mission recovery is possible from a heliocentric orbit (to be discussed in the full paper), it was found that an escape-prevention maneuver could be performed several days after a hypothetical LOI-miss, allowing a return to the desired science orbit around the Moon without leaving the Earths sphere-of-influence (SOI).

Lunar Orbit Insertion↗
DOE OSTI2025

Radiation portal monitor data file format for comprehensive background radiation monitoring

Radiation portal monitors (RPMs) are widely used at border security checkpoints to detect the presence of radioactive materials in people, vehicles, and cargo. Typically, RPM detection systems consist of two pillars equipped with gamma and neutron detectors. To improve detection efficiency, RPMs employ techniques such as a limited energy window, dynamic alarm thresholds, and lead shielding. However, without continuous monitoring of background radiation, signal interpretation can be compromised, because environmental factors and mechanical failures can cause fluctuations. Here, we introduce a daily file format that logs gamma background and neutron background radiation levels continuously over a 24 h period; this format is different from traditional formats that record data only when the RPM is active or occupied. The approach enables RPM operators and analysts to (1) identify and diagnose malfunctioning components, (2) adjust system settings to account for dynamic environmental factors, and (3) use the recorded data to characterize outer space phenomena. Continuous background reporting is essential for identifying issues such as faulty connections, voltage divider failures, and errors in background updates. Continuous background reporting also enables the detection of external influences, including nearby X-ray scanners, temperature fluctuations, rainfall, cosmic radiation, and lunar phase changes. These data files are designed to be easily evaluated and parsed using common tools, and a quick review by an expert is often sufficient for problem diagnosis. We anticipate that continuous background radiation monitoring and these new strategies will significantly improve the accuracy and reliability of RPM systems, reducing the rate of false alarms and enhancing overall system performance.

Background radiation monitoring↗
DOE OSTI2024

Comparison of volatiles evolving from selected highland and mare lunar regolith simulants during vacuum sintering

Volatiles evolving from JSC-1A, NU-LHT-4M and CSM-LHT-1G lunar regolith simulants during in vacuo thermal processing were analyzed using mass spectrometry as a function of temperature. Two high-fidelity simulants, JSC-1A (mare) and NU-LHT-4M (highland), were compared to a newly developed CSM-LHT-1G highland simulant, modified to closely match lunar geochemistry. Large autogenous gas loads were observed for all investigated materials. Mineralogical knowledge was used to identify and attribute individual volatile species to reacting, transforming, or decomposing constituents (hydrates, carbonates, sulfates, sulfides, clays, etc.) of the respective regolith simulant in the self-generated gas environment. Cumulative mass losses for individual simulant components as a function of temperature were quantified using mass spectrometry in conjunction with thermogravimetric analysis. Investigation of the four components of CSM-LHT-1G – anorthosite, basalt, augite, and glass – aided the attribution of volatile species to specific compounds and their respective sources. The results showed significant decomposition of non-lunar phases present in the man-made regolith simulants below the typical glass crystallization temperatures, which paves the way to devising methods for enhancing the fidelity of the simulants. Finally, high gas loads and corrosive gases (HF and HCl) were recognized as potential hazards, pertaining to the development of large testbed facilities.

42 ENGINEERING↗
NASA NTRS1971

The Unified S-band Ground System.

This paper describes how the design of the Unified S-band Ground System evolved from the technology available in the NASA's Deep Space Network and Scientific Satellite Network as well as the Manned Space Flight Network to fulfill the requirements of the Apollo program. The project organization established for this program proved to be an effective management technique for controlling the widely dispersed activities and maintaining the necessary liaison with other organizations involved in the overall program. The Manned Space Flight Network includes systems at three locations employing 26 meter antennas to support the lunar phases of the mission and a number of systems at other locations employing 9 meter antennas for support of the near earth phases of the mission. The tradeoffs of mission requirements and technical capability established the equipment parameters and the network configuration. An extensive checkout program which included the use of aircraft and spacecraft provided a thorough evaluation of the system prior to its commitment to operational support of the missions.

Varson, W. P.↗
NASA NTRS1978

Interpretation of ground-based microwave measurements of the moon using a detailed regolith properties model

A detailed model for the regolith's thermophysical and microwave properties has been used for the interpretation of ground-based measurements of the moon's microwave brightness temperature variation with lunar phase and changes during eclipses. The ground-based measurements include some crucial new lunation variation observations at 2.8, 6.0 and 13.1 cm. The many parameters in the regolith properties model were assigned values based on a careful review of Apollo in situ and lab sample measurements of thermophysical and electrical properties. The first identification of a wavelength-dependent component of scattering is reported.

Gary, B. L.↗
NASA NTRS1994

Space based astronomy: Teacher's guide with activities

This curriculum guide uses hands-on activities to help students and teachers understand the significance of space-based astronomy - astronomical observations made from outer space. The guide contains few of the traditional activities found in many astronomy guides such as constellation studies, lunar phases, and planetary orbits. Instead, it tells the story of why it is important to observe celestial objects from outer space and how to study the entire electromagnetic spectrum. The guide begins with a survey of astronomy related NASA spacecraft. This is followed by a collection of activities in four units: (1) the atmospheric filter; (2) the electromagnetic spectrum; (3) collecting electromagnetic radiation; and (4) down to Earth. A curriculum index identifies the curriculum areas each activity addresses. The guide concludes with a glossary, reference list, a NASA Resources list, and an evaluation card. It is designed for students in grades 5 through 8.

Rosenberg, Carla B.↗
NASA NTRS1995

Theoretical overview and modeling of the sodium and potassium atmospheres of the moon

A general theoretical overview for the sources, sinks, gas-surface interactions, and transport dynamics of sodium and potassium in the exospheric atmosphere of the Moon is given. These four factors, which control the spatial distribution of these two alkali-group gases about the Moon, are incorporated in numerical models. The spatial nature and relative importance of the initial source atoms atmosphere (which must be nonthermal to explain observational data) and the ambient (ballistic hopping) atom atmosphere are examined. The transport dynamics, atmospheric structure, and lunar escape of the nonthermal source atoms are time variable with season of the year and lunar phase because of their dependence on the radiation acceleration experienced by sodium and potassium atoms as they resonantly scatter solar photons. The dynamic transport time of fully thermally accomodated ambient atoms along the surface because of solar radiation acceleration (only several percent of surface gravity) is larger than the photoionization lifetimes and hence unimportant in determining the local density, although for potassium the situation is borderline. The sodium model was applied to analyze sodium observations of the sunward brightness profiles acquired near last quarter by Potter & Morgan (1988b) extending from the surface to an altitude of 1200 km, and near first quarter by Mendillo, Baumgardner, & Flynn (1991), extending in altitude from approximately 1430 to approximately 7000 km. The observations at larger altitudes could be fitted only for source atoms having a velocity distribution with a tail that is mildly nonthermal (like an approximately 1000 K Maxwell-Boltzmann distribution). Solar wind sputtering appears to a be a viable source atom mechanism for the sodium observations with photon-simulated desorption also possible but highly uncertain, although micrometeoroid impact vaporization appears to have a source that is too small and too hot, with likely an incorrect angular distribution about the Moon.

Smyth, William H.↗
NASA NTRS2001

Space-Based Astronomy: An Educator Guide with Activities for Science, Mathematics, and Technology Education

If you go to the country, far from city lights, you can see about 3,000 stars on a clear night. If your eyes were bigger, you could see many more stars. With a pair of binoculars, an optical device that effectively enlarges the pupil of your eye by about 30 times, the number of stars you can see increases to the tens of thousands. With a medium-sized telescope with a light-collecting mirror 30 centimeters in diameter, you can see hundreds of thousands of stars. With a large observatory telescope, millions of stars become visible. This curriculum guide uses hands-on activities to help students and teachers understand the significance of space-based astronomy--astronomical observations made from outer space. It is not intended to serve as a curriculum. Instead, teachers should select activities from this guide that support and extend existing study. The guide contains few of the traditional activities found in many astronomy guides such as constellation studies, lunar phases, and planetary orbits. It tells, rather, the story of why it is important to observe celestial objects from outer space and how to study the entire electromagnetic spectrum. Teachers are encouraged to adapt these activities for the particular needs of their students. When selected activities from this guide are used in conjunction with traditional astronomy curricula, students benefit from a more complete experience.

Vogt, Gregory L.↗
NASA NTRS2014

Sport Transition of JPSS VIIRS Imagery for Night-time Applications

The NASA/Short‐term Prediction, Research, and Transition (SPoRT) Program and NOAA/Cooperative Institute for Research in the Atmosphere (CIRA) work within the NOAA/Joint Polar Satellite System (JPSS) Proving Ground to demonstrate the unique capabilities of the VIIRS instrument. Very similar to MODIS, the VIIRS instrument provides many high‐resolution visible and infrared channels in a broad spectrum. In addition, VIIRS is equipped with a low‐light sensor that is able to detect light emissions from the land and atmosphere as well as reflected sunlight by the lunar surface. This band is referred to as the Day‐Night Band due to the sunlight being used at night to see cloud and topographic features just as one would typically see in day‐time visible imagery. NWS forecast offices that collaborate with SPoRT and CIRA have utilized MODIS imagery in operations, but have longed for more frequent passes of polar‐orbiting data. The VIIRS instrument enhances SPoRT collaborations with WFOs by providing another day and night‐time pass, and at times two additional passes due to its large swath width. This means that multi‐spectral, RGB imagery composites are more readily available to prepare users for their use in GOES‐R era and high‐resolution imagery for use in high‐latitudes is more frequently able to supplement standard GOES imagery within the SPoRT Hybrid GEO‐LEO product. The transition of VIIRS also introduces the new Day‐Night Band capability to forecast operations. An Intensive Evaluation Period (IEP) was conducted in Summer 2013 with a group of "Front Range" NWS offices related to VIIRS night‐time imagery. VIIRS single‐channel imagery is able to better analyze the specific location of fire hotspots and other land features, as well as provide a more true measurement of various cloud and aerosol properties than geostationary measurements, especially at night. Viewed within the SPoRT Hybrid imagery, the VIIRS data allows forecasters to better interpret the more frequent, but coarse GOES Imagery. Night‐time Microphysics and Dust RGB Imagery provides cloud analysis of cloud height, thickness, and composition in order for operational applications such as separating fog from low clouds, dust plume detection, and determining precipitating clouds in radar-void/ blocked regions. The Day‐Night Band has a particular benefit to seeing light from cities, fires, or other emissions as well as the reflection of moonlight off of clouds and smoke plumes, given the right lunar phase and angle. Examples from the VIIRS transition and IEP will be presented.

Fuell, Kevin↗
NASA NTRS2014

Exploration Missions to Host Small Payloads

The next-generation heavy launch vehicle, the Space Launch System (SLS), will provide the capability to deploy small satellites during the trans-lunar phase of the exploration mission trajectory. We will describe the payload mission concept of operations, the payload capacity for the SLS, and the payload requirements. Exploration Mission 1, currently planned for launch in December 2017, will be the first mission to carry such payloads on the SLS.

Cirtain, Jonathan↗
NASA NTRS2016

Enabling Science and Deep Space Exploration through Space Launch System (LSL) Secondary Payload Opportunities

For the first time in almost 40 years, a NASA human-rated launch vehicle has completed its Critical Design Review (CDR). By reaching this milestone, NASA's Space Launch System (SLS) and Orion spacecraft are on the path to launch a new era of deep space exploration. NASA is making investments to expand science and exploration capability of the SLS by developing the capability to deploy small satellites during the trans-lunar phase of the mission trajectory. Exploration Mission 1 (EM-1), currently planned for launch no earlier than July 2018, will be the first mission to carry such payloads on the SLS. The EM-1 launch will include thirteen 6U Cubesat small satellites that will be deployed beyond low earth orbit. By providing an earth-escape trajectory, opportunities are created for advancement of small satellite subsystems, including deep space communications and in-space propulsion. This SLS capability also creates low-cost options for addressing existing Agency strategic knowledge gaps and affordable science missions. A new approach to payload integration and mission assurance is needed to ensure safety of the vehicle, while also maintaining reasonable costs for the small payload developer teams. SLS EM-1 will provide the framework and serve as a test flight, not only for vehicle systems, but also payload accommodations, ground processing, and on-orbit operations. Through developing the requirements and integration processes for EM-1, NASA is outlining the framework for the evolved configuration of secondary payloads on SLS Block upgrades. The lessons learned from the EM-1 mission will be applied to processes and products developed for future block upgrades. In the heavy-lift configuration of SLS, payload accommodations will increase for secondary opportunities including small satellites larger than the traditional Cubesat class payload. The payload mission concept of operations, proposed payload capacity of SLS, and the payload requirements for launch and deployment will be described to provide potential payload users an understanding of this unique exploration capability.

Singer, Jody↗
NASA NTRS2016

Secondary Payload Opportunities on NASA's Space Launch System (SLS) Enable Science and Deep Space Exploration

For the first time in almost 40 years, a NASA human-rated launch vehicle has completed its Critical Design Review (CDR). With this milestone, NASA's Space Launch System (SLS) and Orion spacecraft are on the path to launch a new era of deep space exploration. This first launch of SLS and the Orion Spacecraft is planned no later than November 2018 and will fly along a trans-lunar trajectory, testing the performance of the SLS and Orion systems for future missions. NASA is making investments to expand the science and exploration capability of the SLS by developing the capability to deploy small satellites during the trans-lunar phase of the mission trajectory. Exploration Mission 1 (EM-1) will include thirteen 6U Cubesat small satellites to be deployed beyond low earth orbit. By providing an earth-escape trajectory, opportunities are created for the advancement of small satellite subsystems, including deep space communications and in-space propulsion. This SLS capability also creates low-cost options for addressing existing Agency strategic knowledge gaps and affordable science missions. A new approach to payload integration and mission assurance is needed to ensure safety of the vehicle, while also maintaining reasonable costs for the small payload developer teams. SLS EM-1 will provide the framework and serve as a test flight, not only for vehicle systems, but also payload accommodations, ground processing, and on-orbit operations. Through developing the requirements and integration processes for EM-1, NASA is outlining the framework for the evolved configuration of secondary payloads on SLS Block upgrades. The lessons learned from the EM-1 mission will be applied to processes and products developed for future block upgrades. In the heavy-lift configuration of SLS, payload accommodations will increase for secondary opportunities including small satellites larger than the traditional Cubesat class payload. The payload mission concept of operations, proposed payload capacity of SLS, and the payload requirements for launch and deployment will be described to provide potential payload users an understanding of this unique exploration capability.

Singer, Jody↗
NASA NTRS2017

Manuel Johnson's Tide Record at St. Helena

The astronomer Manuel Johnson, a future President of the Royal Astronomical Society, recorded the ocean tides with his own instrument at St. Helena in 1826-1827, while waiting for an observatory to be built. It is an important record in the history of tidal science, as the only previous measurements at St. Helena had been those made by Nevil Maskelyne in 1761, and there were to be no other systematic measurements until the late 20th century. Johnsons tide gauge, of a curious but unique design, recorded efficiently the height of every tidal high and low water for at least 13 months, in spite of requiring frequent re-setting. These heights compare very reasonably with a modern tidal synthesis based on present-day tide gauge measurements from the same site.Johnsons method of timing is unknown, but his calculations of lunar phases suggest that his tidal measurements were recorded in Local Apparent Time. Unfortunately, the recorded times are found to be seriously and variably lagged by many minutes. Johnsons data have never been fully published, but his manuscripts have been safely archived and are available for inspection at Cambridge University. His data have been converted to computerfiles as part of this study for the benefit of future researchers.

Cartwright, David E.↗