PSI Personnel
Project Description
Objectives: This project will archive Gaskell shape models for the Saturnian satellites listed below. To date there are no Gaskell shape models for Rhea, Iapetus, or Enceladeus within the Planetary Data System (PDS) archive. Current models for Mimas and Phoebe are based on the data available as of 2013. All image data acquired during the Cassini mission, which ended in 2017, have now been archived. This project will generate or update the above five shape models to include the entire Cassini image data set.
Methods: Stereophotoclinometry is a technique that uses the strengths of both stereophotogrammetry and photoclinometry. It has been used on numerous small bodies, such as Eros (Gaskell, 2008b), Dione, Tethys, Mimas, Phoebe (Gaskell, 2011a, 2013a,b,c), Itokawa (Gaskell et al., 2008) and Vesta (Gaskell, 2011b). It has been used by us to generate a shape model of Bennu, as well as features for Natural Feature Tracking (NFT) which will be used for landmark navigation for the OSIRIS-REx mission during sample collection. On April 14, 2020, our NFT capability completed a Checkpoint Rehearsal for sample collection, and we passed with a wide margin. The software and technique were pioneered by R. Gaskell, and the resulting shape models are referred to as ‘Gaskell shape models’. Shape models are used for multiple projects that require knowledge of the surface’s topography. These include geologic mapping, identifying and linking processes with geologic unit, and photometric and spectroscopic studies that require the removal of topographic effects.
References:
Gaskell, R.W., 2008b. Gaskell Eros Shape Model V1.0, NASA Planetary Data System, NEAR-A-MSI-5-EROSSHAPE-V1.0
Gaskell, R.W., 2013a. Gaskell Dione Shape Model V1.0, NASA Planetary Data System, CO-SA-ISSNA/ISSWA-5-DIONESHAPE-V1.0 Gaskell, R.W., 2013b. Gaskell Tethys Shape Model V1.0, NASA Planetary Data System, CO-SA-ISSNA-5-TETHYSSHAPE-V1.0 Gaskell, R.W., 2013c. Gaskell Mimas Shape Model V2.0, NASA Planetary Data System, CO-SA-ISSNA-5-MIMASSHAPE-V2.0 Gaskell, R.W., 2011a. Gaskell Phoebe Shape Model V1.0, NASA Planetary Data System, CO-SA-ISSNA-5-PHOEBESHAPE-V1.0 Gaskell, R.W., Barnouin-Jha, O.S., Scheeres, D.J., Konopliv, A.S., Mukai, T., Abe, S., Saito, J., Ishiguro, M., Kubota, T., Hasimoto,
T., Kawaguchi, J., Yoshikawa, M., Shirakawa, K., Kominato, T., Hirata, N., Demura, H., 2008a. Characterizing and navigating small
bodies with imaging data. Meteoritics & Planet. Sci. 43, Issue 6, 1049 -1061.
Gaskell, R.W., Palmer E.E., Mastrodemos, N., Barnouin, O.S., Jorda, L., Taylor, A.H., 2011b. Mercury and Vesta – Preliminary shape
an topography, 2011 Fall Meeting AGU, San Francisco, CA, Abstract A1576.
Gaskell, R., Saito, J., Ishiguro, M., Kubota, T., Hashimoto, T., Hirata, N., Abe, S., Barnouin-Jha, O., Scheeres, D., 2008y. Gaskell
Itokawa Shape Model V1.0, NASA Planetary Data System, HAY-A-AMICA-5-ITOKAWASHAPE-V1.0Deborah Domingue, Eric Palmer, Ribert Gaskell