Analysis of the magnetic properties experiment data on

The paper presents the results of a new analysis of the data from the Magnetic Properties Experiment onboard the Mars Pathnder Spacecraft. The spectral data from the extended visible region of material adhering to the magnets are presented as well as the time dependence of dust accumulation to the magnets. A new model is developed to estimate the magnetic properties of the accumulated dust. It is found that the optical re ection spectra of the magnetic dust dier slightly from the re ection of ground soil=dust in the vicinity of the lander. Several possible hypotheses are given to account for this dierence. Magnetic dust has been removed from the magnets at least twice during the 80 sol mission by wind gusts, and it is suggested that this happens in a manner similar to sand blasting. A lower limit for the saturation magnetisation of the most magnetic particles is found to be 5 A m2=kg. c © 2000 Elsevier Science Ltd. All rights reserved. 1