Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Land”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Land and Land-use Change in the Climate Sensitive High Plains: An Automated Approach with Landsat

The High Plains is an economically important and climatologically sensitive region of the United States and Canada. The High Plains contain 100,000 sq km of Holocene sand dunes and sand sheets that are currently stabilized by natural vegetation. Droughts and the larger threat of global warming are climate phenomena that could cause depletion of natural vegetation and make this region susceptible to sand dune reactivation. The original proposal was directed toward the use of Landsat TM data to establish the state and ongoing changes of the surface in the 1.2 million sq. km, semi-arid High Plains region of the central US, A key objective was to develop a model to predict the reactivation of the 100,000 sq. km of Holocene dunes found on the High Plains during an extended drought. At least one Landsat 5 image per year for 1985, 1988 and 1996 was obtained for 32 scenes on the High Plains to coincide with wet and dry years. Additional Landsat 7 data were acquired for 1999 and 2000 primarily for Colorado and Nebraska. As luck would have it, there was no severe drought during the study period 1985-2000. Attention was focused on developing methods for mapping dry vs. green vegetation on sparsely vegetated rangelands in sandy soils, since these were the areas most susceptible to surface reactivation during a drought.

Goetz, Alexander F.↗
NASA NTRS2005

[Multi-Scale Convergence of Cold-Land Process Representation in Land-Surface Models, Microwave Remote Sensing, and Field Observations]

The cryosphere is a major component of the hydrosphere and interacts significantly with the global climate system, the geosphere, and the biosphere. Measurement of the amount of water stored in the snow pack and forecasting the rate of melt are thus essential for managing water supply and flood control systems. Snow hydrologists are confronted with the dual problems of estimating both the quantity of water held by seasonal snow packs and time of snow melt. Monitoring these snow parameters is essential for one of the objectives of the Earth Science Enterprise-understanding of the global hydrologic cycle. Measuring spatially distributed snow properties, such as snow water equivalence (SWE) and wetness, from space is a key component for improvement of our understanding of coupled atmosphere-surface processes. Through the GWEC project, we have significantly advanced our understandings and improved modeling capabilities of the microwave signatures in response to snow and underground properties.

Shi, Jiancheng↗
NASA NTRS2005

Aerocapture, Entry, Descent and Landing (AEDL) Human Planetary Landing Systems. Section 10: AEDL Analysis, Test and Validation Infrastructure

Contents include the following: 3 Listing of critical capabilities (knowledge, procedures, training, facilities) and metrics for validating that they are mission ready. Examples of critical capabilities and validation metrics: ground test and simulations. Flight testing to prove capabilities are mission ready. Issues and recommendations.

Arnold, J.↗
NASA NTRS2015

Entry Descent and Landing Workshop Proceedings: Mars2020 Entry, Descent, and Landing Instrumentation (MEDLI2): Project Overview - Volume 1

Aerothermal & TPS: a) Determine Forebody Aerothermal Heating. b) Determine In-depth TPS Temperature. c) Determine Backshell Aerothermal Environment. Aerodynamics and Atmosphere: a) Reconstruct Atmospheric Density, Winds, and Wind-Relative Attitude. b) Determine Hypersonic & Supersonic Aerodynamics Forces. c) Base Pressure Contribution to Drag.

Bose, Deepak↗
NASA NTRS2013

Entry Descent and Landing Workshop Proceedings: The Mars Science Laboratory (MSL) Entry, Descent and Landing Instrumentation (MEDLI) Hardware - Volume 1

Objectives: Measure Pressure: a) Confirm spacecraft aerodynamics. b) Independently measure attitude. c) Determine density profile. d) Determine wind component. Measure Temperature: a) Verify heating levels on spacecraft surface. b) Determine recession amount and rate. c) Validate material response at Mars conditions. The better we understand the Mars entry environment, the better we can design the next spacecraft.

Munk, Michelle M.↗
NASA NTRSDate not supplied

Analysis of the Approach Direction of the Human Landing System to a South Pole Landing Site Subject to Lighting and Communication Constraints

The NRHO used as the staging orbit for crewed missions to the lunar surface by the HLS remains nearly perpendicular to the Earth-Moon line of sight, however, due to the libration of the Moon the location of the South Pole is ever shifting beneath it. DTE communication as well as ground illumination conditions near the South Pole coincide with lunar libration, with approximately 2-week cycles of DTE communication and solar availability. Additionally, the constant shifting of the South Pole region with respect to the NRHO leads to variations in the nominal HLS approach path to the surface in order to maintain near in-plane alignment of the NRHO, LLO, and approach phase. Making adjustments to the nominal approach path to achieve desired communication and lighting conditions quickly raises in-space ∆V. This analysis compares the ∆V impact of several trajectory strategies that could be used to alter the HLS approach path.

HLS↗