Cover Page/Proposal Summary

ROSS-00    NRA 00-OSS-01

Date Due: 4/28/2000

NASA PROCEDURE FOR HANDLING PROPOSALS 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: Planets, Satellites, and Rings

Major Equipment Proposal? No

Do you intend to submit an Education/Public Outreach (E/PO) proposal? No

Proposal Title:

Observation of Calcium and Search for New Species in Mercury's Atmosphere

Abbreviated Proposal Title:

Calcium and New Species in Mercury's Atmosphere

Principal Investigator:

Dr. Rosemary M. Killen Instrumentation and Space Research Division 15 Southwest Research Institute 6220 Culebra Road P.O. Drawer 28510 San Antonio, TX 78228-0510 Phone: 210-522-2719   Fax: 210-543-0052   E-mail: rosemary@whipple.space.swri.edu

Signature	Date
_____________________________________	____________

Co-Investigators and Collaborators:
Type	Name	Affiliation	E-mail
Sci Co-I	Mr. Thomas Bida	CARA	tbida@keck.hawaii.edu
Sci Collab	Dr. Michel Festou	Obs. Midi-Pyrenees	festou@ast.obs-mip.fr
Sci Collab	Dr. Alan Fitzsimmons	Univ. Queens-Belfast	A.Fitzsimmons@Queens-Belfast.ac.uk
Sci Collab	Dr. Andrew E. Potter	NSO	potter@lpi.usra.edu

Proposal Summary:

It is hard to imagine a more important and less understood object in the inner solar system than Mercury. The physical and chemical state of the planet Mercury has sweeping implications for the origin of our solar system. The atmosphere is the system most easily studied to deduce the composition of and physical processes acting on the regolith. The source and sink processes for the atmosphere are interesting in their own right, but because the atmosphere is derived from the surface and interior of the planet they will give us valuable insight into the composition, structure and history of the planet. The atmospheric Ca abundance is a critical datum in the determination of the surface composition and the active source processes. Because calcium is not easily vaporized, as are the previously studied elements (H, He, Na and K), it is likely that only ion sputtering is active in promoting this species into the atmosphere. In contrast, at least three processes are active in promoting sodium into the atmosphere: photon-stimulated desorption, ion-sputtering and meteoritic vaporization. We have detected Ca in Mercury's atmosphere with a column abundance of 1x108 atom cm-2 over the poles. The line width suggests Ca of extreme temperature with velocities up to 3/4 of escape velocity. This proposed program 1) will further define the atmospheric Ca abundance, distribution and temporal variability and 2) will search for additional species. Our observational objectives are: to measure the distribution of calcium (Ca I) in the atmosphere of Mercury at a number of epochs; to measure its velocity distribution; to observe at the principal visible and near-IR bands of CaO to detect or to derive strict upper limits on this species; to observe at the resonance wavelengths of Ca II, OH, Al I, and Rb I; and to obtain sufficient coordinated observations of the distributions of both Ca and Na to determine the broad similarities or dissimilarities of the distributions of the two elements.

Certification of Compliance with Applicable Executive Orders and U.S. Code By submitting the proposal identified in this Cover Sheet/Proposal Summary in response to this NRA or AO, the Authorizing Official of the proposing institution (or the individual proposer if there is no proposing institution) as identified below: certifies that the statements made in this proposal are true and complete to the best of his/her knowledge; agrees to accept the obligations to comply with NASA award terms and conditions if an award is made as a result of this proposal; and confirms compliance with all provisions, rules, and stipulations set forth in the three Certifications contained in this NRA [namely, (i) Certification Regarding Debarment, Suspension, and Other Responsibility Matters Primary Cover Transactions, (ii) Certification Regarding Lobbying, and (iii) Certification of Compliance with the NASA Regulations Pursuant to Nondiscrimination in Federally Assisted Programs]. Willful provision of false information in this proposal and/or its supporting documents, or in reports required under an ensuing award, is a criminal offense (U.S. Code, Title 18, Section 1001).