The International Soil Moisture Network: serving Earth system science for over a decade
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54 ENVIRONMENTAL SCIENCES↗
Engineering topics
Larson, Kristine
Publications and source records attributed to Larson, Kristine.
Ultraviolet Testing of Space Suit Materials for Mars
Human missions to Mars may require radical changes in the approach to extra-vehicular (EVA) suit design. A major challenge is the balance of building a suit robust enough to complete multiple EVAs under intense ultraviolet (UV) light exposure without losing mechanical strength or compromising the suit's mobility. To study how the materials degrade on Mars in-situ, the Jet Propulsion Laboratory (JPL) invited the Advanced Space Suit team at NASA's Johnson Space Center (JSC) to place space suit materials on the Scanning Habitable Environments with Raman & Luminescence for Organics and Chemicals (SHERLOC) instrument's calibration target of the Mars 2020 rover. In order to select materials for the rover and understand the effects from Mars equivalent UV exposure, JSC conducted ground testing on both current and new space suit materials when exposed to 2500 hours of Mars mission equivalent UV. To complete this testing, JSC partnered with NASA's Marshall Space Flight Center to utilize their UV vacuum chambers. Materials tested were Orthofabric, polycarbonate, Teflon, Dacron, Vectran, spectra, bladder, nGimat coated Teflon, and nGimat coated Orthofabric. All samples were measured for mass, tensile strength, and chemical composition before and after radiation. Mass loss was insignificant (less than 0.5%) among the materials. Most materials loss tensile strength after radiation and became more brittle with a loss of elongation. Changes in chemical composition were seen in all radiated materials through Spectral Analysis. Results from this testing helped select the materials that will fly on the Mars 2020 rover. In addition, JSC can use this data to create a correlation to the chemical changes after radiation-which is what the rover will send back while on Mars-to the mechanical changes, such as tensile strength.
Larson, Kristine↗
Ultraviolet Testing of Space Suit Materials for Mars
Human missions to Mars may require radical changes in the approach to extra-vehicular (EVA) suit design. A major challenge is the balance of building a suit robust enough to complete multiple EVAs under intense ultraviolet (UV) light exposure without losing mechanical strength or compromising the suit's mobility. To study how the materials degrade on Mars in-situ, the Jet Propulsion Laboratory (JPL) invited the Advanced Space Suit team at NASA's Johnson Space Center (JSC) to place space suit materials on the Scanning Habitable Environments with Raman & Luminescence for Organics and Chemicals (SHERLOC) instrument's calibration target of the Mars 2020 rover. In order to select materials for the rover and understand the effects from Mars equivalent UV exposure, JSC conducted ground testing on both current and new space suit materials when exposed to 2500 hours of Mars mission equivalent UV. To complete this testing, JSC partnered with NASA's Marshall Space Flight Center to utilize their UV vacuum chambers. Materials tested were Orthofabric, polycarbonate, Teflon, Dacron, Vectran, spectra, bladder, nGimat coated Teflon, and nGimat coated Orthofabric. All samples were measured for mass, tensile strength, and chemical composition before and after radiation. Mass loss was insignificant (less than 0.5%) among the materials. Most materials loss tensile strength after radiation and became more brittle with a loss of elongation. Changes in chemical composition were seen in all radiated materials through Spectral Analysis. Results from this testing helped select the materials that will fly on the Mars 2020 rover. In addition, JSC can use this data to create a correlation to the chemical changes after radiation-which is what the rover will send back while on Mars-to the mechanical changes, such as tensile strength.
Larson, Kristine↗
GNSS H2O: a global network of in situ hydrologic sensors derived from GNSS data
UNKNOWN
Wong, Cynthia↗
How we can measure snow, sea ice, and other things with reflected GPS signals
UNKNOWN
Larson, Kristine↗
Testing of Space Suit Materials for Mars
Human missions to Mars may require radical changes in our approach to EVA suit design. A major challenge is the balance of building a suit robust enough to complete 50 EVAs in the dirt under intense UV exposure without losing mechanical strength or compromising its mobility. We conducted ground testing on both current and new space suit materials to determine performance degradation after exposure to 2500 hours of Mars mission equivalent UV. This testing will help mature the material technologies and provide performance data that can be used by not only the space suit development teams but for all Mars inflatable and soft goods derived structures from airlocks to habitats.
Larson, Kristine↗
Mars 2020 Rover SHERLOC Calibration Target
The Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC) instrument is a deep ultraviolet (UV) Raman Fluorescence instrument selected as part of the Mars 2020 rover instrument suite. SHERLOC will be mounted on the rover arm and its primary role is to identify carbonaceous species in martian samples. The SHERLOC instrument requires a calibration target which is being designed and fabricated at JSC as part of our continued science participation in Mars robotic missions. The SHERLOC calibration target will address a wide range of NASA goals to include basic science of interest to both the Science Mission Directorate and Human Exploration and Operations Mission Directorate.
Graff, Trevor↗
A Long-Term Comparison Between GPS Carrier-Phase and Two-way Satellite Time Transfer
We have conducted GPS carrier-phase time-transfer experiment between the Master Clock at USNO in Washington DC and the Alternate Master Clock at Schriever Air Force Base near Colorado Springs, Colorado. These clocks are also monitored on an hourly basis with two-way satellite time-transfer (TWSTT) measurements. We compare the performance of the GPS carrier-phase and TWSTT systems over a 167-day period. Apart from an overall constant time offset (due to unknown delays in the GPS hardware at both ends), we find that the systems agree within +/- 1ns, with a drift of 1.9 +/- 0.1 ps/d. For averaging times of a day, the carrier-phase and TWSTT systems have a frequency uncertainty of 2.5 and 5.5 parts in 10(exp 15), respectively.
Larson, Kristine↗