Radar Backscatter from Mars: Properties of Rock-Strewn Surfaces

Campbell, B. A.

doi:10.1006/icar.2000.6566

Cited by 26 publications

(17 citation statements)

References 20 publications

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“…The radar brightness in the InSight region is similar to that of a field site on Kilauea (Campbell 2001) with a moderately rocky surface, only slightly higher than that of the VL1 site (−17 dB), and considerably higher than that of the VL2 site (−19 dB). Thus, surface rock abundance in the 2-10 cm range at InSight is likely slightly to significantly higher than at the two VL sites.…”

Section: Arecibo Roughness Analysissupporting

confidence: 52%

“…The radar images have a best spatial resolution of ∼3 km, but the echoes are sensitive to small-scale (0.1-1 m) surface roughness and to rocks larger than a few cm within the signal's penetration depth (1-3 m). Arecibo image data provide a strong constraint on surface roughness by comparison with well-calibrated observations of terrestrial-analog surfaces (e.g., Campbell 2001;2009;. Low-power returns may indicate a fine-grained mantling material, which can be further investigated by other means.…”

Section: Arecibo Roughness and Reflectivitymentioning

confidence: 99%

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Selection of the InSight Landing Site

et al. 2016

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The selection of the Discovery Program InSight landing site took over four years from initial identification of possible areas that met engineering constraints, to downselection via targeted data from orbiters (especially Mars Reconnaissance SPAC 11214 layout: Small Condensed v.2.1 file: spac321.tex (ELE) class: spr-small-v1.2 v.2016/06/09 Prn:2016/12/02; 14:37 p. 1/91» « d o c to p i c : R e v i e w P a p e rn u m b e r i n g s t y l e : C o n t e n t O n l yr e f e r e n c e s t y l e : a p s » latitude (initially 15°S-5°N and later 3°N-5°N for solar power and thermal management of the spacecraft), ellipse size (130 km by 27 km from ballistic entry and descent), and a load bearing surface without thick deposits of dust, severely limited acceptable areas to western Elysium Planitia. Within this area, 16 prospective ellipses were identified, which lie ∼600 km north of the Mars Science Laboratory (MSL) rover. Mapping of terrains in rapidly acquired CTX images identified especially benign smooth terrain and led to the downselection to four northern ellipses. Acquisition of nearly continuous HiRISE, additional Thermal Emission Imaging System (THEMIS), and High Resolution Stereo Camera (HRSC) images, along with radar data confirmed that ellipse E9 met all landing site constraints: with slopes <15°at 84 m and 2 m length scales for radar tracking and touchdown stability, low rock abundance (<10 %) to avoid impact and spacecraft tip over, instrument deployment constraints, which included identical slope and rock abundance constraints, a radar reflective and load bearing surface, and a fragmented regolith ∼5 m thick for full penetration of the heat flow probe. Unlike other Mars landers, science objectives did not directly influence landing site selection. AUTHOR'S PROOF

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Section: Arecibo Roughness Analysissupporting

confidence: 52%

Section: Arecibo Roughness and Reflectivitymentioning

confidence: 99%

Selection of the InSight Landing Site

et al. 2016

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“…A similar functional dependence was found between the backscatter coefficient and the simulationderived values of the rms height. Campbell [46] used the three wavelengths provided by the AIRSAR system (5.7, 24, and 68 cm) and showed that the rms height of a rock-strewn surface in Hawaii modulates the backscatter in a similar manner to "continuous" rough terrain [1.7]. This result is important in extending the use of empirical models to rocky terrain on the Moon and Mars.…”

Section: B Empirical Models Based On Scale-dependent Roughness Parammentioning

confidence: 99%

Scale-Dependent Surface Roughness Behavior and Its Impact on Empirical Models for Radar Backscatter

Campbell

2009

IEEE Trans. Geosci. Remote Sensing

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Abstract-One goal of radar remote sensing is the extraction of terrain statistics and surface dielectric properties from backscatter data for some range of wavelengths, incidence angles, and polarizations. This paper addresses empirical approaches used to estimate terrain properties from radar data over a wider range of roughness than permitted by analytical models. Many empirical models assume, at least implicitly, that roughness parameters like rms height or correlation length are independent of the horizontal length scale over which they are measured, in contrast to recent surveys of natural terrain, which show that self-affine, or powerlaw scaling, between horizontal scale and roughness statistics is very common. The rms slope at the horizontal scale of the illuminating wavelength s(A) is directly related to the variogram or structure function of a self-affine surface, can be readily obtained from field-measured topography, and, when used in an empirical model, avoids the need for arbitrary wavelength-dependent terms. To facilitate comparison with earlier approaches, an expression that links the rms height at some profile length with the rms (Allan) deviation at an equivalent horizontal sampling interval is obtained from numerical simulations. An empirical model for polarimetric scattering as a function of 6'(A) at 35°-60° incidence from smooth to rugged lava surfaces is derived and compared with earlier models for backscatter from modestly rough soil surfaces. The asymptotic behavior of polarization ratios for the lava flows suggests that the depolarization of linear-polarized illuminating signals occurs as a first-order process, likely through single scattering by rock edges or other discontinuities, rather than as the solely multiple-scattering effect predicted by some analytical models. Efforts to fully understand radar scattering from geological surfaces need to incorporate wavelength-scale roughness, perhaps through computational simulations.

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“…From 1964 to the late 1980s, Earth-based radar revolutionized our understanding of planetary motions and distances, provided the first hints of the unique properties of the icy outer planet satellites (Ostro et al 1992), mapped the Moon in support of Apollo (Thompson & Dyce 1966;Pettengill & Thompson 1968;Thompson et al 1970;Thompson 1974Thompson , 1987Zisk et al 1974), and paved the way (Campbell et al 1972 to orbital radar mapping of Venus by the Pioneer-Venus, Venera 15/16, and Magellan missions (Saunders et al 1992;Butrica 1996). Analysis of the global dataset collected by Magellan greatly enlarged the community within planetary science familiar with the interpretation of radar measurements, and motivated studies to understand the relationship between echo properties and natural surface roughness.…”

Section: Introductionmentioning

confidence: 99%

Planetary Geology with Imaging Radar: Insights from Earth-based Lunar Studies, 2001–2015

Campbell

2016

PASP

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Radar exploration of the Solar System changed dramatically during and beyond the period of the Magellan mission to Venus. These changes included an expansion of the community familiar with microwave data, and the forging of a strong connection with polarimetric scattering models developed through terrestrial field measurements and airborne radar studies. During the period, advances in computing power and imaging techniques also allowed Earth-based radar experiments to acquire data at the highest spatial resolutions permitted by their transmitter systems. This paper traces these developments through a case study of lunar observations over the past 15 years, and their implications for ongoing and future Solar System radar studies.

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Radar Backscatter from Mars: Properties of Rock-Strewn Surfaces

Cited by 26 publications

References 20 publications

Selection of the InSight Landing Site

Selection of the InSight Landing Site

Scale-Dependent Surface Roughness Behavior and Its Impact on Empirical Models for Radar Backscatter

Planetary Geology with Imaging Radar: Insights from Earth-based Lunar Studies, 2001–2015

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