Engineering topics
Publications and source records attributed to James B Garvin.
In this paper we will illustrate an electromagnetic sounder model for Martian regolith we have developed. The model is based on Kirchhoff approximation. The incidence beam is assumed to be a Gaussian beam. The model is suited to study the near surface (upper 10 meters) ice detection capability of the L-band Synthetic Aperture Radar (SAR) for the international Mars Ice Mapping (iMIM) mission.
The Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) mission described herein has been selected for flight to Venus as part of the NASA Discovery Program. DAVINCI will be the first mission to Venus to incorporate science driven flybys and an instrumented descent sphere into a unified architecture. The anticipated scientific outcome will be a new understanding of the atmosphere, surface, and evolutionary path of Venus as a possibly once-habitable planet and analog to hot terrestrial exoplanets. The primary mission design for DAVINCI as selected features a preferred launch in summer/fall 2029, two flybys in 2030, and descent sphere atmospheric entry by the end of 2031. The in situ atmospheric descent phase subsequently delivers definitive chemical and isotopic composition of the Venus atmosphere during an atmospheric transect above Alpha Regio. These in situ investigations of the atmosphere and near infrared descent imaging of the surface will complement remote flyby observations of the dynamic atmosphere, cloud deck, and surface near infrared emissivity. The overall mission yield will be at least 60 Gbits (compressed) new data about the atmosphere and near surface, as well as the first unique characterization of the deep atmosphere environment and chemistry, including trace gases, key stable isotopes, oxygen fugacity, constraints on local rock compositions, and topography of a tessera.
As the next wave of robotic exploration of Mars commences in the early 2020s, led by a multiplicity of space-faring nations and emerging commercial entities such as SpaceX and Blue Origin, the possibility of paradigm-shifting discoveries about the Red Planet is high. In this midst, the always-lurking question of “why Mars?” merits reconsideration. The answer ranges from seeking to enhance high-tech prowess and leadership, evolving our understanding of geology, chemistry, physics, and meteorology, to providing intellectual inspiration to a broad cross-section of the society.
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This work implemented a 3-D Electromagnetic Scattering model to gain a better understanding in the observations of L- and P-band radar returns from the multi-layered Martian upper surface layer. The model is based on the Integral Equation Model (IEM) developed by Adrian Fung. Our model implementation treats the upper surface (regolith) layer as an inhomogeneous medium with irregular boundaries for a range of Martian surface and shallow subsurface scenarios. The model is well suited to study the near subsurface (upper 10 meters of surface sediments) ice detection capability of the L-band (32 cm wavelength) Synthetic Aperture Radar (SAR) planned for the international Mars Ice Mapping (I-MIM) mission launching later in the 2020s.