jba

Research

Mars
I use orbital images and datasets from instruments aboard the Mars Reconnaissance Orbiter to interpret the deposition, erosion, and aqueous alteration history of various sites on Mars. I use high resolution images from HiRISE, CTX, and HRSC to display the surface geomorphology, and I use CRISM and THEMIS to classify rocks from their reflected spectral signatures. I focus on characterizing the stratigraphy of past rover landing sites and locating sites worthy of future missions.
Conference abstracts and posters can be found here: Jim Bell Group Publications

I am one of the Payload Downlink Leads (PDL) for the Pancam instrument on the MER Opportunity Rover. I monitor the camera's health and performance, make sure images are downlinked from the rover, participate in operations meetings, and generate "quick-look" data products for team reports.

Moon
I study the distribution of ballistic impact ejecta on the Moon under the guidance of Professors Mark Robinson and Erik Asphaug. By modeling lunar impacts we aim to quantify the offset and probability of ejecta deposits near the antipode. Lunar gravity data from the GRAIL instrument and topography from the LOLA instrument can help us redefine the trajectories and landing locations of material ejected during large impact cratering events.

Asteroids
Past research: The absorption and delayed re-emission of sunlight on a spinning asteroid can, over long periods of time, change the body's orbit. I examined these non-gravitational forces by tracking photon momentum through a three dimensional ray-tracing thermal model. The ray-tracing model accounted for the momentum transfer associated with absorption, shadowing, rescattering and emission of solar and infrared photons. This new model calculates the Yarkovsky effect by summing the forces on each facet of the asteroid's shape model and integrating over time. We used R. Gaskell’s Itokawa shape model from Hayabusa data and found the momentum vectors and forces on each of the 49,152 triangular facets. We compared our results with those presented in Peterson 1976 and Spitale & Greenberg 2001.