MIMOS II explained

MIMOS II is the miniaturised Mössbauer spectrometer, developed by Dr. Göstar Klingelhöfer at the Johannes Gutenberg University in Mainz, Germany, that is used on the Mars Exploration Rovers Spirit and Opportunity for close-up investigations on the Martian surface of the mineralogy of iron-bearing rocks and soils.^{[1] [2]}

MIMOS II uses a Cobalt-57 gamma ray source of about 300 mCi at launch which gave a 6-12 hr time for acquisition of a standard MB spectrum during the primary mission on Mars, depending on total Fe content and which Fe-bearing phases are present. Cobalt-57 has a half-life of only 271.8 days (hence the extended measuring times now on Mars after over a decade).

The MIMOS II sensorheads used on Mars are approx 9 cm x 5 cm x 4 cm^[2] and weigh about 400g^[3]

The MIMOS II system also includes a circuit board of about 100g.^[3]

Notes and References

1. The miniaturized Mössbauer spectrometer MIMOS II for extraterrestrial and outdoor terrestrial applications: A status report. Klingelhöfer G. . Bernhardt B. . Foh J. . Bonnes U. . Rodionov D. . De Souza P. A. . Schroder C. . Gellert R. . Kane S. . Gutlich P. . Kankeleit E. . Hyperfine Interactions. 144. 371–379. 2002. 1 . 10.1023/A:1025444209059. 2002HyInt.144..371K. 94640811 .
2. Web site: THE MINIATURISED MOESSBAUER SPECTROMETER MIMOS II: APPLICATION FOR THE "PHOBOS-GRUNT" MISSION. . Klingelhoefer . etal . 2007 .
3. Web site: THE MINIATURIZED MÖSSBAUER SPECTROMETER MIMOS II OF THE ATHENA PAYLOAD FOR THE 2003 MER MISSIONS . Klingelhoefer . etal . 2003 .