PLANETARY3D: A PHOTOGRAMMETRIC TOOL FOR 3D TOPOGRAPHIC MAPPING OF PLANETARY BODIES

Planetary remote sensing images are the primary datasets for high-resolution topographic mapping and modeling of the planetary surfaces. However, unlike the mapping satellites for Earth observations, cameras onboard the planetary satellites generally present special imaging geometries and configurations, which makes the stereo photogrammetric process difficult and requires a large number of manual interactions. At the Hong Kong Polytechnic University, we developed a unified photogrammetric software system, namely Planetary3D, for 3D topographic mapping modeling of various planetary bodies using images collected by various sensors. Planetary3D consists of three modules, including: (1) the pre-processing module to deliver standardized image products, (2) the bundle adjustment module to alleviate the inconsistencies between the images and possibly the reference frame, and (3) the dense image matching module to create pixel-wise image matches and produce high quality topographic models. Examples of using three changeling datasets, including the MRO CTX, MRO HiRISE and Chang’E-2 images, have revealed that the automatic pipeline of Planetary3D can produce high-quality digital elevation models (DEMs) with favorable performances. Notably, the notorious jitter effects visible on HiRISE images can be effectively removed and good consistencies with the reference DEMs are found for the test datasets by the Planetary3D pipeline

Summary of the Results from the Lunar Orbiter Laser Altimeter after Seven Years in Lunar Orbit

In June 2009 the Lunar Reconnaissance Orbiter (LRO) spacecraft was launched to the Moon. The payload consists of 7 science instruments selected to characterize sites for future robotic and human missions. Among them, the Lunar Orbiter Laser Altimeter (LOLA) was designed to obtain altimetry, surface roughness, and reflectance measurements. The primary phase of lunar exploration lasted one year, following a 3-month commissioning phase. On completion of its exploration objectives, the LRO mission transitioned to a science mission. After 7 years in lunar orbit, the LOLA instrument continues to map the lunar surface. The LOLA dataset is one of the foundational datasets acquired by the various LRO instruments. LOLA provided a high-accuracy global geodetic reference frame to which past, present and future lunar observations can be referenced. It also obtained high-resolution and accurate global topography that were used to determine regions in permanent shadow at the lunar poles. LOLA further contributed to the study of polar volatiles through its unique measurement of surface brightness at zero phase, which revealed anomalies in several polar craters that may indicate the presence of water ice. In this paper, we describe the many LOLA accomplishments to date and its contribution to lunar and planetary science

UNDERSTANDING LUNAR VOLCANIC PROCESSES AND MARE SURFACE AGE-DATING VIA REMOTE SENSING

Ph.D

Forty-first Lunar and Planetary Science Conference

Special sessions were: A New Moon: Lunar Reconnaissance Orbiter Results ; Water in the Solar System: Incorporation into Primitive Bodies and Evolution ; A New Moon: LCROSS, Chandrayaan, and Chang-E-1 ; Water in the Solar System: Moon ; A New Moon: Spectral Constraints on Lunar Crustal Composition ; Characterizing Near-Earth Objects ; A New Moon: Lunar Volcanism and Impact. This CD-ROM contains the contents, program, abstracts, and author indexes for the 41st Lunar and Planetary Science Conference.by Lunar and Planetary Institute, NASA Johnson Space Centerconference co-chairs, Stephen Mackwell, Lunar and Planetary Institute [and] Eileen Stansbery, NASA Johnson Space Center.PARTIAL CONTENTS: Roughness and Radar Polarimetry of Lunar Polar Craters: Testing for Ice Deposits / B.J. Thomson, P.D. Spudis, D.B.J. Bussey, L. Carter, R.L. Kirk, C. Neish, G. Patterson, R.K. Raney, H. Winters, and the Mini-RF Team--Formation of Jupiter's Atmosphere from a Supernova-Contaminated Molecular Cloud / H.B. Throop--Ancient Lunar Dynamo: Absence of Evidence is Not the Evidence of Absence / S.M. Tikoo, B.P. Weiss, J. Buz, I. Garrick-Bethell, T.L. Grove, and J. Gattaccaea--Dark Dunes in Ka'u Desert (Hawaii) as Terrestrial Analogs to Dark Dunes on Mars / D. Tirsch, R.A. Craddock, and R. Jaumann--Mars Ice Condensation and Density Orbiter / T.N. Titus, T. Prettyman, A. Brown, T.I. Michaels, and A. Colaprete--The Atacama Desert Cave Shredder: A Case for Conduction Thermodynamics / T.N. Titus, J.J. Wynne, D. Ruby, and N. Cabrol

Photometric Investigations of Lunar Landing Sites and Silicic Regions using LRO Narrow Angle Camera Images

The reflectance properties of a planetary surface are related to the physical and compositional properties of that body. Photometry is a powerful method for determining differences in composition and regolith structure, and photometric data from orbital images coupled with soil sample data can greatly enhance our understanding of the regolith properties of our nearest neighbor, the Moon. At the time of writing, the United States has no operating missions on the Moon and no future plans to send robots or humans to study our nearest neighbor, so we must rely on remote sensing data to provide us with information about the lunar surface. This dissertation uses photometric studies of high-resolution Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) images and Hapke photometric modeling to understand the behavior and composition of lunar soil at spacecraft landing sites and areas of non-mare volcanism on the Moon. This work has implications for future mission planning and implementation, including landing site selection, landing safety, and sampling strategies. Topics include: i) the effects of rocket exhaust on lunar soil reflectance properties at the Apollo, Luna, and Surveyor landing sites, ii) photometric analysis of the recent Chang\u27e-3 landing site and comparison of reflectance alterations with those of older landing sites, and iii) compositional variations at regions of non-mare volcanism using NAC photometry and spectral analysis of glassy analog materials. Rocket exhaust from the Apollo, Luna, and Surveyor descent engines disturbed the regolith at their landing sites, causing the soil to become more reflective. These surface alterations, which we call blast zones , are still evident in NAC images, and I use photometry and Hapke modeling to show that the increase in reflectance was caused by smoothing, destruction of fine-scale surface structure (i.e., fairy-castle structure), and possibly redistribution of fine particles. The recent Chinese Chang\u27e-3 spacecraft also disturbed the soil at its landing site in the same fashion, and I show that the reflectance changes and area of disturbance are in family with those of older landing sites, indicating reflectance changes have not changed on the order of decades. I determine the relationship between lander mass and blast zone area and use this to make predictions of the area of soil disturbance for future missions. Finally, using photometric methods optimized from landing site studies, I place compositional constraints on areas of non-mare and intrusive volcanism and confirm that these areas exhibit a range of evolved silicic compositions (dacite, andesite, and rhyolite) and pyroclastic deposits, and should be considered as scientific targets for future landed sample-return missions

Examination of volcanism and impact cratering on terrestrial bodies

Thesis (Ph.D.) University of Alaska Fairbanks, 2023Exploring and expanding our understanding of the planets (i.e., planetary science) encompasses a vast array of topics and disciplines. This dissertation concentrates on the surficial processes of and examination of terrestrial planets, primarily via the study of volcanism and impact cratering. The first project starts with an exploration of NIR remote sensing techniques as applied to Venus. This work found that NIR remote sensing at the clement conditions just beneath the cloud deck provide vastly improved imaging capability. This improved visibility is most notable for the tesserae, regions of Venus of great interest to the scientific community. Radar imagery and derived data products were then used to survey 21 mid-sized volcanoes on the surface of Venus. Similar to volcanoes at larger diameters, the midsized volcanoes of Venus are significantly flatter than those on other terrestrial bodies. Several of these volcanoes also show deformation that requires a negligibly thin lithosphere some time after the emplacement of the construct. The third project then evaluates the hazards involved with safely placing a lander on the Venusian tesserae and examines potential methods by which to detect and then avoid these hazards. Safely placing a suite of scientific instruments on tesserae is necessary to answer long-standing questions about Venus. Current technologies put relevant hazards at the edge of detection (i.e., zero fault tolerance) and can execute divert maneuvers of only a few tens of meters. Investment in hazard detection and avoidance technologies is necessary to bring safety margins to acceptable levels; data from future missions - while helpful - will be insufficient to select safe landing zones prior to launch. Oblique impact cratering is a ubiquitous event (approximately half of all impacts are at 45 or less). Our poor understanding of this process leaves a significant amount of information buried and waiting to be uncovered. Low-velocity oblique impact experiments were conducted at John's Hopkins University's Applied Physics Laboratory Planetary Impact Lab to better understand the oblique impact process and prepare for high velocity experiments at similar impact angles. These experiments also sought to understand the effect of target tilt, which is currently necessary at existing experimental facilities in order to simulate changes in impact angle smaller than 15°. These experiments show that target tilt significantly amplifies oblique characteristics (e.g., aspect ratio, butterfly ejecta). The time-delayed and spatially offset transference of energy from the impactor to the target is important in determining the excavation process and final crater morphology and ejecta distribution