PDS: The Planetary Atmospheres NodeJovian System Data Analysis Program
Cover Page/Proposal Summary
ROSS-99 NRA 99-OSS-01
Date Due: 5/5/99
|
This proposal shall be used and disclosed for evaluation purposes only, and a copy of this Government notice shall be applied to any reproduction or abstract thereof. Any authorized restrictive notices that the submitter places on this proposal shall also be strictly complied with. Disclosure of this proposal for any reason outside the Government evaluation purposes shall be made only to the extent authorized by the Government. |
| Proposal Type: New Proposal |
| Proposal Category: Satellites and Rings |
| Major Equipment Proposal? No |
| Do you intend to submit an Education/Public Outreach (E/PO) proposal? No |
| Proposal Title: |
| Photopolarimetry of the Galilean Satellites with the Galileo PPR during GEM |
| Abbreviated Proposal Title: |
| GEM Satellite Photopolarimetry |
| Principal Investigator: |
| Dr.
Terry Martin Earth and Planetary Atmospheres Earth and Space Sciences Mail Stop 169-237 Jet Propulsion Lab. 4800 Oak Grove Drive Pasadena, CA 91109-8099 Phone: 818-354-2178 Fax: 818-393-4619 E-mail: tzmartin@pop.jpl.nasa.gov |
| Signature | Date |
| _____________________________________ | ____________ |
| Co-Investigators and Collaborators: | |||
| Type | Name | Affiliation | |
| Sci Co-I | Dr. Jay D. Goguen | JPL | jdg@scn1.jpl.nasa .gov |
Proposal Summary:
This incremental proposal extends FY 1999 work funded under JSDAP by including GEM phase data of special value, particularly for Europa. These include the first global-scale polarimetric maps of Europa, at 92 and 98° phase angle. Additional effort is needed to calibrate the data, provide geometry information, and archive. The Galileo Photopolarimeter Radiometer (PPR) measured the first set of complete phase curves (polarization vs. phase angle) for the Galilean satellites, including the first such data for any high-albedo icy body. Unique simultaneous photometry and polarimetry at three wavelengths from 410 to 945 nm, together with unprecedented mapping of Ganymede, Callisto and Europa offer a powerful data set for investigating the surface texture of these diverse bodies in a manner complementing that provided by imaging and spectroscopy. Lunar data from the Galileo Earth encounters verifies the behavior of the PPR polarimetry. Modelling of the polarization curves will use code by Mishchenko that allows realistic particle shapes, as well as a range of sizes and refractive indices. Such modelling has shown promise in reproducing atmospheric polarization behavior for the Earth. Goguen showed that atmospheric techniques are applicable for high-albedo surfaces. Analysis of the PPR data for the Galilean satellites will lead to improved knowledge of the fine-scale surfaces of those bodies. Correlation of mapped intensity/polarization behavior with existing maps, imaging, and NIMS data will define local variations in the style of surface alteration. Providing new knowledge of the surfaces of the Galilean satellites, this work will: 1. Strengthen available clues about the character of the surfaces, and the mechanisms that produce them. 2. Focus future NASA investigations by pointing out regions of anomalous behavior. 3. Assist future NASA robotic exploration by providing engineering information relevant to thermal, composition, and particle size environments.
