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United States multi-sector land use and land cover base maps to support human and Earth system models

Abstract Earth System Models (ESMs) require current and future projections of land use and landcover change (LULC) to simulate land-atmospheric interactions and global biogeochemical cycles. Among the most utilized land systems in ESMs are the Community Land Model (CLM) and the Land-Use Harmonization 2 (LUH2) products. Regional studies also use these products by extending coarse projections to finer resolutions via downscaling or by using multisector dynamic (MSD) models. One such MSD model is the Global Change Analysis Model (GCAM), which has its own independent land module, but often relies on CLM or LUH2 as spatial inputs for its base years. However, this requires harmonization of thematically incongruent land systems at multiple spatial resolutions, leading to uncertainty and error propagation. To resolve these issues, we develop a thematically consistent LULC system for the conterminous United States adaptable to multiple MSD frameworks to support research at a regional level. Using empirically derived spatial products, we developed a series of base maps for multiple contemporary years of observation at a 30-m resolution that support flexibility and interchangeability amongst LUH2, CLM, and GCAM classification systems.

Oliver, Jay

Erosive Wear Characterization of Materials for Lunar Construction

NASA s Apollo missions revealed that exhaust from the retrorockets of landing spacecraft may act to significantly accelerate lunar dust on the surface of the Moon. A recent study by Immer et al. (C. Immer, P.T. Metzger, P.E. Hintze, A. Nick, and R. Horan, Apollo 12 Lunar Module exhaust plume impingement on Lunar Surveyor III, Icarus, Vol. 211, pp. 1089-1102, 2011) investigated coupons returned to Earth from the Surveyor III lunar probe which were subjected to lunar dust impingement by the Apollo 12 Lunar Module landing. Their study revealed that even with indirect impingement, the spacecraft sustained erosive damage from the fast-moving lunar dust particles. In this work, results are presented from a series of erosive wear experiments performed on 6061 Aluminum using the JSC-1AF lunar dust simulant. Optical profilometry was used to investigate the surface after the erosion process. It was found that even short durations of lunar dust simulant impacting at low velocities produced substantial changes in the surface.

Mpagazehe, Jeremiah N.

A Hybrid CFD/Engineering Model Tool for Lunar Lander Surface Erosion Prediction

Plume-Surface Interaction (PSI) between lander engine plumes and landing area regolith poses risks to the landers and space exploration missions through view obscuration and high-energy ejecta impacts from eroded particle clouds and vehicle tilting from plume-induced craters. To address these risks, NASA MSFC Fluid Dynamics Branch (ER42) has developed a cascade of predictive simulation capabilities for PSI, including the recent development of a hybrid CFD/engineering model tool that allows for rapid PSI simulations with a descending/ascending vehicle and an eroding surface. The development of this fully-coupled, moving body/eroding surface simulation capability is detailed along with a demonstration of the tool’s capabilities on the Apollo 12 Lunar Module landing. Predictions of eroded mass flow rates as a function of time are verified against Apollo 12 flight data, from which the developed, viscous erosion model has been calibrated.

Plume Surface Interaction

A Hybrid CFD/Engineering Model Tool for Lunar Lander Surface Erosion Prediction

Plume-Surface Interaction (PSI) between lander engine plumes and landing area regolith poses risks to the landers and space exploration missions through view obscuration and high-energy ejecta impacts from eroded particle clouds and vehicle tilting from plume-induced craters. To address these risks, NASA MSFC Fluid Dynamics Branch (ER42) has developed a cascade of predictive simulation capabilities for PSI, including the recent development of a hybrid CFD/engineering model tool that allows for rapid PSI simulations with a descending/ascending vehicle and an eroding surface. The development of this fully-coupled, moving body/eroding surface simulation capability is detailed along with a demonstration of the tool’s capabilities on the Apollo 12 Lunar Module landing. Predictions of eroded mass flow rates as a function of time are verified against Apollo 12 flight data, from which the developed, viscous erosion model has been calibrated.

Plume Surface Interaction

Geology of the Apollo 14 landing site.

Apollo 14 landed in the Fra Mauro region of the moon, within about 1,100 m of a 90 m high ridge of the Fra Mauro formation, interpreted as being ejecta from the Imbrium Basin. The primary geologic objective of the mission was to sample ejecta from Cone Crater, which is 340 m in diameter and penetrates at least 60 m into the ridge. Data from the mission strongly support the Imbrian ejecta origin for the Fra Mauro formation. Returned samples and photographs show that ejecta from Cone Crater is composed of composite breccias that include multiple clasts of still older, pre-Imbrian, breccias. Cone Crater ejecta displays a wide range of thermal metamorphism effects. Samples from the valley where the Lunar Module landed, which was not on a recognizable ray of ejecta from Cone Crater, are predominantly fines and poorly consolidated breccias formed by the disintegration of Fra Mauro rocks and probably are not volcanic rocks as had been postulated before the mission.

Sutton, R. L.

Investigating Particle-Particle Electrostatic Effects on Charged Lunar Dust Transport via Discrete Element Modeling

NASA surface exploration missions have always seen negative effects of dust including the Apollo missions. The astronaut-witnessed unusual behavior of the dust particles that surround the vehicle after engine cutoff has the potential to have more of an influence on surface systems dust loading than the high velocity lunar rocket plume ejecta in the landing process. The levitation and transport of the fine components of regolith on lunar surface has been linked to electrostatic effects and electric field, but so far there is no accurate model considering the inter-particle electrostatic interactions, especially when the particles are charged by rocket plume or other mechanical interactions due to exploration activities. This study is proposed to investigate the dynamics of charged lunar regolith with a discrete element method (DEM) approach focusing on the inter-particle interactions and contact charge transfer. The grain dynamics is coupled with mechanical and electrical particle interactions, and both short- and long-range interactions between spherical particles are incorporated. A tribo-charging model based on instantaneous collisions between particles is adopted and validated by comparing the simulation results to existing experimental data. Sensitivity analysis is conducted to quantify the effects of initial charge, tribo-charging, and E-field on transport of lunar dust based on JSC-1 simulants with a radius of 50 lm. DEM simulations are also conducted in a near realistic lunar environment with the estimations of initial conditions that shows the difference in position and velocity distributions between charged particles and uncharged particles. The results indicate that the charged dust particles have higher dispersion of position and velocity by several orders of magnitude due to electrostatic effects. This provides a potential explanation for the phenomena of the approximately 30 s dust lofting following Apollo Lunar Module landing.

Lunar dust

Vacuum measurements on the lunar surface.

Results of measurements of neutral gas pressure on the lunar surface made with a cold cathode ionization gauge carried to the moon by Apollo 14. The vacuum quality at the landing site is much influenced by the adsorption of rocket gases and their later release. During surface operations by the astronauts, the pressure was near 10 to the minus 8th torr. No data were obtained between the time of the surface operations and lunar sunset about 12 days later, at which time the temperature fell rapidly to the vicinity of 100 K. The pressure was about 10 to the minus 12th torr shortly after sunset, but intermittent releases of gas, perhaps from within the moon itself, occasionally raised the pressure by less than an order of magnitude for as long as a day or two at a time and on one occasion to about 10 to the minus 10th torr for about an hour. At lunar sunrise, as the surface was warmed rapidly to about 300 K, the pressure rose rapidly to about 10 to the minus 10th torr, most likely due to the release of absorbed gases in the immediate landing area or on the landing module itself. For comparison with interplanetary vacuum conditions, the directed pressure of the solar wind is usually less than 10 to the minus 11th torr and the pressure of random gas motion within the solar wind, less than 10 to the minus 13th torr.

Johnson, F. S.

Apollo 17 traverse gravimeter experiment /Preliminary results/

Preliminary results of the traverse gravimeter experiment successfully performed during the Apollo 17 mission are discussed. An earth-moon gravity tie was established. On the basis of several readings, a gravity value of 162,695 + or - 5 mgal was obtained at the lunar-module landing site in the Taurus-Littrow valley. Free-air and Bouguer corrections were applied to the gravity data. The resultant Bouguer anomaly, analyzed with a two-dimensional approximation, shows a relative gravity maximum of about 25 to 30 mgal over the Taurus-Littrow valley. This maximum is interpreted in terms of a 1-km-thick block of basalt flow with a positive density contrast of 0.8 g/cu cm relative to the highland material on either side.

Talwani, M.

Apollo-Soyuz pamphlet no. 1: The flight

The goals of the Apollo-Soyuz Test Project are described in this first in a series of nine pamphlets designed as a curriculum supplement for teachers, supervisors, curriculum specialists, and textbook writers as well as for the general public. Aspects of the space flight covered include descriptions of the astronaut-cosmonaut meeting and of the spacecraft and landing module; spacecraft launch; control, and rendezvous; crew work schedule; and telemetry. Experiments performed are listed in tables, and their major results are summarized.

Page, L. W.

Balloons on planet Venus - Final results

On June 11 and 15, 1985 two packages with balloons have been inserted in the atmosphere of Venus from the Soviet VEGA landing modules. This paper summarizes the pressure, temperature, wind illumination and backscattering data from the balloons.

Blamont, J.