Browse Topic: Soils
Planetary regolith (dust) is an aggregation of various minerals and different particle sizes. Collection, storage, processing, and disposal of this material are very challenging in the harsh planetary environment. Extraterrestrial operations involving In-Situ Resource Utilization (ISRU) require conveying of regolith. The regolith needs to be transported from the planetary surface to chemical/thermal reaction vessels, and spent (processed) regolith needs to be conveyed to a disposal area.
A method was developed for transfer of lunar soil into and out of process equipment. The Lunar Materials Handling System (LMHS) conveys solids to a process vessel, provides a gas-tight seal, prevents seal contamination, and minimizes wear from abrasive particles. The LMHS increases equipment life and minimizes process losses, thereby increasing overall in-situ resource utilization (ISRU) leverage. The LMHS is based on a seal arrangement by which lunar or Mars regolith can be repeatedly introduced into, and removed from, reaction chambers operating under a wide range of conditions. An integrated LMHS was demonstrated during operation in a one-cubic-meter vacuum chamber using hydrogen reduction as an ISRU process demonstration platform.
The interaction between the solar wind and the Earth’s magneto - sphere results in “space weather.” To determine the true nature of the solar wind-magnetosphere interaction, scientists require global measurements of processes occurring at the bow shock, in the magnetosheath, and at the magnetopause. Such observations can only be obtained from imaging this interaction globally. This will produce a paradigm shift similar to how satellite imaging revolutionized terrestrial weather forecasting.
This technology was developed for the Soil Moisture Active Passive (SMAP) mission and for the IRAD-FY13 Technology for Radiometer RFI Noise Detection & Mitigation Based on HHT2. Spacecraft beyond the present state-of-the-art passive radiometry will make use of natural thermal emissions to remotely sense Earth phenomena of interest to science (soil moisture, for example) in the technologically challenging microwave L-band. In this 1.4-GHz band (used by SMAP), a terrestrial source thermal signal emission to space suffers less attenuation by the intervening atmosphere. Unfortunately, the relative insensitivity of the L-band region to atmospheric effects also makes it an extremely attractive spectral range for wireless communications and radars that are causing radio frequency interference (RFI) with the spaceflight science radiometer instruments’ terrestrial phenomenon signal of interest, even as this band is protected by radio-communication regulations. Detection and excision or mitigation of the RFI-contaminated measurements is a challenge to the state of the art.
The in situ production of vital gases and raw materials on the lunar surface is an integral part of NASA’s exploration vision. Development of processes for extraction of oxygen and metallics from the lunar regolith will be vital not only for life support on the lunar surface, but also for spacecraft propulsion to travel further beyond low Earth orbit. This will have a direct impact on cost reduction associated with minimizing the raw material mass from Earth. Aside from utilization of in situ resources, one of the significant limitations of current simulant is the lack of constituents, such as agglutinates. These agglutinates are typically mineral fragments of the lunar regolith that are held together by glass and, depending on location, may constitute 60% to 70% of the lunar regolith.
A fast Fourier transform (FFT) was developed as part of the Soil-Moisture Active/Passive (SMAP) project. The FFT was created on 16-bit data arriving at a rate of 48 MHz to run on a resource-constrained, space-grade field programmable gate array (FPGA).
There is a need to develop an efficient method for processing lunar regolith in support of future missions to colonize the Moon. A system for heating lunar regolith (“moon soil”) using microwaves for processing has been developed. It relies on an enhanced heating effect based on a large temperature gradient forming when a sample of lunar regolith under microwave radiation emits heat from its surface rapidly as the core is melting. Once the core melts, the sample absorbs microwave energy more readily. This molten lunar regolith would then exit the sample tube, and the lunar regolith could then be introduced into molds for forming a desired structure or building block.
Miniaturization in microelectronics is beginning to reach its physical limits, say researchers at the Helmholtz-Zentrum Dresden-Rossendorf Institute of Ion Beam Physics and Materials Research, who are seeking new methods for device fabrication.
Until the time of this reporting, when a space vehicle required a reference signal for inertial pointing, the choices were a signal beacon from an Earth location, the Earth radiance in the visible spectrum, or a star tracker. However, limitations can arise from using these techniques. For example, the signal beacon suffers from limited signal power (either in RF or optical) and will constrain the application to limited ranges, errors due to stray-light and centroiding limit the accuracy of a star tracker, and the spatial/temporal variability of the Earth’s albedo and its illumination by the Sun introduces limitations when used in the visible or near infrared light.
The water-vapor continuum absorption plays an important role in the radiative balance in the Earth’s atmosphere. It has been experimentally shown that for ambient atmospheric conditions, the continuum absorption scales quadratically with the H2O number density and has a strong, negative temperature dependence (T dependence). Over the years, there have been three different theoretical mechanisms postulated: far-wings of allowed transition lines, water dimers, and collision-induced absorption. The first mechanism proposed was the accumulation of absorptions from the farwings of the strong allowed transition lines. Later, absorption by water dimers was proposed, and this mechanism provides a qualitative explanation for the continuum characters mentioned above. Despite the improvements in experimental data, at present there is no consensus on which mechanism is primarily responsible for the continuum absorption.
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