Workshop on Early Mars (1997) 3017.pdf THE MAGNETIC PROPERTIES EXPERIMENT ON MARS PATHFINDER. Jens Martin Knudsen, Haraldur Pall Gunnlaugsson, Morten Bo Madsen, Stubbe F. Hviid, Walter Goetz, Niels Bohr Institute for Astronomy, Physics and Geo- physics, Universitetsparken 5, DK-2100 Copenhagen , Denmark.
Introduction 2 A remarkable result from the Viking missions to Mars in 1976 was the discovery that the Martian soil is highly magnetic, in the sense that the soil is attracted by small permanent 1 magnets [1,2]. 4 The Viking landers carried two types of permanent mag- 3 nets, a weak and a strong magnet. The surface magnetic field
and surface magnetic field gradient of the strong type magnet 1
were 250 mT and 100 Tm , respectively. The corresponding 1 numbers for the weak magnet were 70 mT and 30 Tm . Both types were mounted on the backhoe of the soil sampler, where they were exposed to the soil. A strong type magnet 5 was mounted in the Reference Test Chart (RTC) which was exposed to wind born particles exclusively. At both landing sites both backhoemagnets were saturated 3 with magnetic particles after few insertions into the soil. The RTC magnets gradually became saturated with magnetic dust
during the mission. ath nder lander. The lab els refer to 1:
Based on the returned pictures of the amount of soil Figure 1: The P
wo sets of Magnet Arrays, 2: Tip Plate Magnet, 3: clinging to the magnets, it was estimated that the Martian The t
dust contain between 1% and 7% of a strongly magnetic Ramp Magnets, 4: Imager IMP and 5: The So journer
ver. phase, most probably a ferrimagnetic ferric oxide intimately Ro
dispersed throughout the soil. Limits for the saturation
2 1
<
magnetization s were advanced: 1 Am (kg (soil))