49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083) 2109.pdf INVESTIGATING SOURCES OF MERCURY’S CRUSTAL MAGNETIC FIELD: FURTHER MAPPING OF MESSENGER MAGNETOMETER DATA. L. L. Hood1, J. S. Oliveira2,3, P. D. Spudis4, V. Galluzzi5, 1Lunar & Planetary Lab, 1629 E. University Blvd., Univ. of Arizona, Tucson, AZ 85721, USA;
[email protected], 2ESA/ESTEC, SCI-S, Keplerlaan 1, 2200 AG Noordwijk, Netherlands; 3CITEUC, Geophysi- cal & Astronomical Observatory, University of Coimbra, Coimbra, Portugal (
[email protected] ); 4Lunar & Planetary Institute, USRA, Houston, TX; 5INAF, Istituto di Astrofisica e Planetologia Spaziali, Rome, Italy. Introduction: A valuable data set for investigating the orbit tracks was accomplished in two substeps. crustal magnetism on Mercury was obtained by the First, a cubic polynomial was least-squares fitted to the NASA MErcury Surface, Space ENvironment, GEo- raw radial component time series for each orbit pass. chemistry, and Ranging (MESSENGER) Discovery Second, the deviation from 5o running averages was mission during the final year of its existence [1]. Alti- calculated to eliminate wavelengths greater than about tude normalized maps of the crustal field covering part 215 km. At 60oN, the spacecraft altitude decreased of one side of the planet (90oE to 270oE; 35oN to75oN) from 35 km on March 16 to 5.2 km on April 2 when an have previously been constructed from low-altitude orbit correction burn occurred, increasing the altitude magnetometer data using an equivalent source dipole to 28 km. Several other orbit correction burns pre- (ESD) technique [2,3]. Results showed that the stron- vented the altitude at 60oN from decreasing below 8.8 gest crustal field anomalies in this region are concen- km during the period from April 2 to 23.