GPR and magnetic minerals at mars temperatures

摘要: Orbital and earth-based remote sensing infrared spectroscopy, along with in situ magnet tests, Mossbauer, thermal emission spectroscopy have determined the presence of magnetic minerals on Mars. The iron oxide magnetite grey hematite been confirmed by Spirit Opportunity rovers. Elemental compositions including nickel sulfur also observed, which titanium can produce a wide range from paramagnetic through ferromagnetic species. Lalboratory measurements electrical properties at Mars ambient temperatures ground penetrating radar frequency produced surprisingly strong dielectric relaxations, as well expected properties. At average annual surface temperature 213 K, has relaxation near 10 MHz, two relaxations 15 MHz 200 MHz. These processes are strongly dependent, moving about factor lower each K decrease temperature. Thus over Sol, between day night, these will move MARSIS orbital sounder other proposed systems. Also surprising, weakly stronger losses than more range. addition to this miature Curie (above become paramagnetic) into day-night range, would make signature night it disappear ihe higher daytime temperatures. This is problem for orbiter since ionosphere absorbs energy be strongest niglht, severely limiting possibilities depth penetration. Future systems rovers carefully choose frequencies times operation maximize However, dependence function implies broadband system might able versus profile.