[Previous] | [Session 39] | [Next]
L.J. Harcke, H.A. Zebker (Stanford University), R.F. Jurgens, M.A. Slade (Jet Propulsion Laboratory), B.J. Butler (National Radio Astronomy Observatory), J.K. Harmon (Arecibo Observatory)
We plan several radar imaging measurements of Europa, Ganymede, and Callisto during Jovian opposition in November/December 2000. These include Goldstone 3.5~cm and Arecibo 12.6~cm monostatic observations, and a Goldstone/VLA 3.5~cm bistatic configuration. The monostatic experiments should produce higher resolution radar cross section maps than those available today as a result of improved hardware performance and the use of long-code modulation to compensate for the overspread nature of the reflected signals. Transmitter and receiver upgrades to the Arecibo observatory will allow imaging at 10's of km resolution at 12.6~cm, with comparable resolution using the Goldstone 3.5~cm monostatic system. The bistatic Goldstone/VLA experiment will permit resolution of the north/south ambiguity inherent in delay-Doppler imaging. Because Jovian opposition occurs during Earth's northern hemisphere winter, we expect greater phase stability for Goldstone/VLA bistatic observations, as atmospheric water vapor levels will be much lower than during previous observations in summer 1991. Data reduction will entail long-code delay-Doppler imaging for the monostatic radars, and aperture synthesis for Goldstone/VLA bistatic data. We intend to use the resulting images to map spatial variations in radar cross section and correlate them with optical and spectroscopic images, and to investigate the spatial extent and absolute cross section of coherent backscatter phenomena noted in prior radar studies. We also plan to analyze the multiwavelength radar observations to constrain crustal fracture distributions at centimeter scales, and thus suggest geophysical resurfacing processes. This work is supported by the National Science Foundation Planetary Astronomy Program.