
NSF Org: |
AST Division Of Astronomical Sciences |
Recipient: |
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Initial Amendment Date: | August 27, 2018 |
Latest Amendment Date: | August 27, 2018 |
Award Number: | 1819209 |
Award Instrument: | Standard Grant |
Program Manager: |
Martin Still
mstill@nsf.gov (703)292-4290 AST Division Of Astronomical Sciences MPS Directorate for Mathematical and Physical Sciences |
Start Date: | September 1, 2018 |
End Date: | August 31, 2023 (Estimated) |
Total Intended Award Amount: | $366,037.00 |
Total Awarded Amount to Date: | $366,037.00 |
Funds Obligated to Date: |
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History of Investigator: |
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Recipient Sponsored Research Office: |
1700 E FORT LOWELL RD STE 106 TUCSON AZ US 85719-2395 (520)622-6300 |
Sponsor Congressional District: |
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Primary Place of Performance: |
1700 East Fort Lowell, Suite 10 Tucson AZ US 85719-2395 |
Primary Place of
Performance Congressional District: |
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Unique Entity Identifier (UEI): |
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Parent UEI: |
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NSF Program(s): | PLANETARY ASTRONOMY |
Primary Program Source: |
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Program Reference Code(s): |
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Program Element Code(s): |
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Award Agency Code: | 4900 |
Fund Agency Code: | 4900 |
Assistance Listing Number(s): | 47.049 |
ABSTRACT
An accurate determination of the surface composition of planets is essential for understanding the processes that have shaped our Solar System. Beyond Earth, mineralogy is studied using observations from telescopes, orbiting satellites, and in the case of Mars, landers and rovers. It is essential to have accurate "libraries" of measurements showing how different minerals reflect light of different colors. Without comparison samples, a match cannot be made. Materials that are common on Earth have been well studied. However, the surface of Mars is not yet well described in terms of materials that are common in terrestrial studies. Non-crystalline materials ("amorphous") that are rich in water ("hydrated") are ubiquitous on Mars yet are not well studied on Earth. The investigators propose to create a library of reflectance measurements for hydrated amorphous materials that are likely to be found on Mars. They will study how the light reflectance varies with temperature, and how weathering by acids changes the reflectance of a sample. They will include undergraduate students in the research and expect that at least six undergraduate thesis or independent study projects will emerge from this project. As co-PI Dyar is a faculty member at Mount Holyoke (a women's college) and the Five Colleges Astronomy Consortium, many of the student participants are expected to be women.
The objectives of the work are to determine the stability and transformation products of amorphous ferric sulfate salts and salt mixtures, measure the spectra of possible regolith materials a) coated with these materials and b) mixed with these materials; and to use the laboratory spectra to search for and map spectral features of amorphouse ferric sulfates, amorphous mixed salts, and amorphous salt coatings in Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and Mars Global Surveyor Thermal Emission Spectrometer (TES) data.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The surface of Mars is covered with a coating of dust underlain by altered and then more pristine surface rocks. The altered rocks contain a mixture of primary basaltic glass and minerals with a second class of minerals and non-crystalline (a.k.a. “amorphous”) phases that result from chemical reactions with surface water. Although established spectroscopic techniques perform well with simple mineral mixtures, there is a need to understand characteristics of the amorphous materials in order to trace back the geologic history of the Martian surface.
This project sought to understand the conditions under which these amorphous phase form by making synthetic amorphous phases from chemical compounds in the laboratory and varying relevant conditions, including chemical composition, temperature, and humidity. We learned that these phases are incredibly stable against re-crystallization, suggesting that they may remain amorphous for significant amounts of time on the Martian surface or shallow subsurface. They also appear to be resistant to mechanical breakdown by wind erosion when they are formed at low temperature.
Once synthesized, the resultant materials were characterized at Mars surface temperatures using techniques typically employed by rovers and orbiters on Mars: Raman, ultraviolet, visible, and infrared spectroscopies along with x-ray diffraction. The extensive dataset produced by this project will greatly increase the spectral reference libraries for such materials so that laboratory analogues can be compared to the findings from the rover, lander, and orbiter data for Mars. Furthermore, detailed analyses of these spectra across multiple wavelength ranges is providing vital clues to their detectability orbiter data.
The resultant laboratory spectra were then used to search for and map the presence of amorphous phase on the Mars surface using data from the Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Many positive identifications were found, so future work will be needed to cross-reference them to specific minerals. Results also allowed us to focus our regions where amorphous phases occur with high probability. It was found that amorphous mixtures are incredibly similar to the pure Mars soil in many cases, and may be almost impossible to identify uniquely on Mars at the resolution of current orbital data sets.
Last Modified: 11/13/2023
Modified by: Elizabeth Sklute
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