Science results from sixteen years of MRO SHARAD operations

Putzig, N. E.; Seu, R.; Morgan, G. A.; Campbell, B. A.; Perry, M. R.; Mastrogiuseppe, Marco

doi:10.1016/j.icarus.2023.115715

Cited by 14 publications

(5 citation statements)

References 79 publications

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“…We map radar reflections in 304 single-orbit 2D radargrams processed from data collected by the SHARAD instrument onboard the MRO spacecraft that has been in Martian orbit since 2006 (Seu, Phillips, Alberti, et al, 2007). SHARAD emits a single chirped pulse centered at 20 MHz with a bandwidth of 10 MHz, resulting in a range resolution of 15 m in free space, or ∼8-20 m in geologic materials including water and carbon-dioxide ice after data processing; the windowing applied during processing coarsens the range resolution by a factor of ∼2 (Putzig et al, 2023). We traced and extracted geographic and power information from the SPLD surface reflector, LRZ bottom boundary reflector, and SPLD basal reflector (if present), using the same methodology discussed by Abu Hashmeh et al (2022).…”

Section: Methodsmentioning

confidence: 99%

Radar Attenuation Characteristics of Low Reflectivity Zones in the Martian South Polar Layered Deposits

Abu Hashmeh,

Whitten,

Russell

et al. 2024

JGR Planets

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Both sets of Martian polar layered deposits (PLDs) display semi‐rhythmic reflector stratigraphy in radargrams. The southern PLDs (SPLD), among other peculiarities, also contain widespread, distinctive deposits with few to no reflections that commonly occur at or near the top of the stratigraphic column. Here, we study the low reflectivity zones (LRZs) to determine whether they exhibit radar properties indicative of non‐water ice. We find that the previously reported CO2‐ice LRZ exhibits a distinct radar signature compared to all other LRZs. We also found behavior that suggests that the other LRZs may contribute to increased radar signal attenuation, which does not support a CO2 ice composition. We observe many instances of LRZs comprising the entire SPLD column and find that the radar attenuation varies across different LRZs, suggesting unique properties within each of these deposits. Variable radar attenuation of LRZs may be connected to differences in bulk compositions, radar‐sensitive roughness characteristics, and/or distributions of stratigraphic materials.

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Section: Methodsmentioning

confidence: 99%

Radar Attenuation Characteristics of Low Reflectivity Zones in the Martian South Polar Layered Deposits

Abu Hashmeh,

Whitten,

Russell

et al. 2024

JGR Planets

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“…This layer is interpreted as the boundary between ice-rich south-polar layered deposit materials and the bedrock (Plaut et al [129]). In the northern polar region, both MARSIS and SHARAD radars detected reflection signals indicating the boundary between the ice layer and the substrate (Picardi et al [19], Phillips et al [130], Putzig et al [131]). In the mid-latitude regions of Mars, as temperatures rise, surface water ice sublimates, revealing various forms of water ice in different areas, such as glacier deposits in the eastern part of the Hellas basin, abundant water ice in the Deuteronilus Mensae region, and extensive subsurface ice water in the Utopia Planitia (Bramson et al [43], Stuurman et al [132], Plaut et al [133]).…”

Section: Radar Observationmentioning

confidence: 99%

Water Ice Resources on the Shallow Subsurface of Mars: Indications to Rover-Mounted Radar Observation

Zheng,

Ding,

et al. 2024

Remote Sensing

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The planet Mars is the most probable among the terrestrial planets in our solar system to support human settlement or colonization in the future. The detection of water ice or liquid water on the shallow subsurface of Mars is a crucial scientific objective for both the Chinese Tianwen-1 and United States Mars 2020 missions, which were launched in 2020. Both missions were equipped with Rover-mounted ground-penetrating radar (GPR) instruments, specifically the RoPeR on the Zhurong rover and the RIMFAX radar on the Perseverance rover. The in situ radar provides unprecedented opportunities to study the distribution of shallow subsurface water ice on Mars with its unique penetrating capability. The presence of water ice on the shallow surface layers of Mars is one of the most significant indicators of habitability on the extraterrestrial planet. A considerable amount of evidence pointing to the existence of water ice on Mars has been gathered by previous researchers through remote sensing photography, radar, measurements by gamma ray spectroscopy and neutron spectrometers, soil analysis, etc. This paper aims to review the various approaches utilized in detecting shallow subsurface water ice on Mars to date and to sort out the past and current evidence for its presence. This paper also provides a comprehensive overview of the possible clues of shallow subsurface water ice in the landing area of the Perseverance rover, serving as a reference for the RIMFAX radar to detect water ice on Mars in the future. Finally, this paper proposes the future emphasis and direction of rover-mounted radar for water ice exploration on the Martian shallow subsurface.

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“…The SHARAD data used to map the TMPs in Bramson et al. (2019) and used here can be accessed in Putzig (2021).…”

Section: Data Availability Statementmentioning

confidence: 99%

“…The data set containing the output climate model parameters for each candidate model of Table 1 and their significance criteria is available in Izquierdo (2023). The SHARAD data used to map the TMPs in Bramson et al (2019) and used here can be accessed in Putzig (2021).…”

Section: Data Availability Statementmentioning

confidence: 99%

Local Ice Mass Balance Rates via Bayesian Analysis of Mars Polar Trough Migration

Izquierdo,

Bramson,

McClintock

et al. 2023

JGR Planets

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With the aim of better understanding the past depositional environment of the north polar region of Mars, we infer local ice accumulation and retreat rates in the area between 86° and 87°N and 16°–20°E. We follow a novel approach utilizing a Bayesian framework with observations of bounding surfaces associated with the migration of two polar spiral troughs. Over time, spiral troughs have migrated toward the north pole due to ice accumulation, sublimation, and wind transport. We relate the record of trough migration with local ice accumulation and retreat rates using a phenomenological migration model and explore the climate parameters that affect these rates using a Markov chain Monte Carlo algorithm. Using this data‐driven approach, we find best fit mean accumulation rates of 0.11–0.18 mm/yr in the upper 500 m of the stratigraphy of our study region. These mean accumulation rates correspond to trough ages of over 4 Myr, which implies that the north polar cap is older than most current assumptions. We also find that the relationship between accumulation rates and the obliquity of Mars is complex, with periods of positive correlation occurring in the last several Myr. Future work extending this analysis to all troughs in the cap will further constrain these relationships and ages.

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Science results from sixteen years of MRO SHARAD operations

Cited by 14 publications

References 79 publications

Radar Attenuation Characteristics of Low Reflectivity Zones in the Martian South Polar Layered Deposits

Radar Attenuation Characteristics of Low Reflectivity Zones in the Martian South Polar Layered Deposits

Water Ice Resources on the Shallow Subsurface of Mars: Indications to Rover-Mounted Radar Observation

Local Ice Mass Balance Rates via Bayesian Analysis of Mars Polar Trough Migration

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