The Microscopic Imagers (MI) on the Mars Exploration Rovers, Spirit and Opportunity, have returned images of Mars with higher resolution than any previous camera system, allowing detailed petrographic and sedimentological studies of the rocks and soils. Designed to simulate a geologist’s hand lens, the MI cameras were mounted on the rovers’ instrument arms. They can resolve objects 0.1 mm across or larger. As part of the daily MER operations process, targets for the MI and other arm instruments were selected by using available Pancam, Navcam, and Hazcam imagery. The MI routinely observed targets that were investigated by the other ARM instruments to study surface details, to provide context for the spectrometer data, and to examine the results of rock abrasion tool (RAT) brushing and grinding activities (paraphrased from Ken Herkonhoff's Science article, Science vol 305, August 6, 2004).
- Herkenhoff, K. E. and 22 others (2003). Athena Microscopic Imager Investigation. J. Geophys. Res. 108, 8065, doi:10.1029/2003JE002076.
- Herkenhoff, K. E. and 22 others (2004). Textures of the Soils and Rocks at Gusev Crater from Spirit’s Microscopic Imager. Science 305, 824.
- Herkenhoff, K. E. and 32 others (2004). Evidence from Opportunity’s Microscopic Imager for Water on Meridiani Planum. Science 306, 1727.
- Herkenhoff, K. E. and 23 others (2006), Overview of the Microscopic Imager Investigation during Spirit's first 450 sols in Gusev crater, J. Geophys. Res., 111, E02S04, doi:10.1029/2005JE002574.
- Herkenhoff, K. E., M. P. Golombek, E. A. Guinness, J. B. Johnson, A. Kusack, L. Richter, R. Sullivan, and S. Gorevan (2008). In-situ observations of the physical properties of the Martian surface. In The Martian Surface: Composition, Mineralogy, and Physical Properties (J. F. Bell III, ed.), Cambridge University Press.
- Herkenhoff, K. E., J. P. Grotzinger, A. H. Knoll, S. M. McLennan, C. M. Weitz, R. A. Yingst, R. C. Anderson, B. Archinal, R. E. D. Arvidson, J. Barrett, K. J. Becker, J. F. Bell, C. Budney, M. G. Chapman, D. A. Cook, B. L. Ehlmann, B. J. Franklin, L. R. Gaddis, D. Galuszka, P. Garcia, P. E. Geissler, T. M. Hare, E. Howington-Kraus, J. R. Johnson, L. Keszthelyi, R. L. Kirk, P. D. Lanagan, E. M. Lee, C. Leff, J. Maki, K. F. Mullins, T. Parker, B. Redding, M. Rosiek, M. H. Sims, L. A. Soderblom, N. Spanovich, R. Springer, S. W. Squyres, D. Stolper, R. Sucharski, T. Sucharski, R. J. Sullivan, and J. Torson (2008), Surface processes recorded by rocks and soils on Meridiani Planum, Mars: Microscopic Imager observations during Opportunity's first three extended missions, J. Geophys. Res. 113, E12S32, doi:10.1029/2008JE003100.