Space Sci Rev (2010) 150: 285–302 DOI 10.1007/s11214-009-9607-5 The Lunar Reconnaissance Orbiter Miniature Radio Frequency (Mini-RF) Technology Demonstration Stewart Nozette · Paul Spudis · Ben Bussey · Robert Jensen · Keith Raney · Helene Winters · Christopher L. Lichtenberg · William Marinelli · Jason Crusan · Michele Gates · Mark Robinson Received: 17 November 2008 / Accepted: 6 November 2009 / Published online: 13 January 2010 © Springer Science+Business Media B.V. 2010 Abstract The Miniature Radio Frequency (Mini-RF) system is manifested on the Lunar Re- connaissance Orbiter (LRO) as a technology demonstration and an extended mission science instrument. Mini-RF represents a significant step forward in spaceborne RF technology and architecture. It combines synthetic aperture radar (SAR) at two wavelengths (S-band and X-band) and two resolutions (150 m and 30 m) with interferometric and communications functionality in one lightweight (16 kg) package. Previous radar observations (Earth-based, and one bistatic data set from Clementine) of the permanently shadowed regions of the lunar poles seem to indicate areas of high circular polarization ratio (CPR) consistent with volume scattering from volatile deposits (e.g. water ice) buried at shallow (0.1–1 m) depth, but only at unfavorable viewing geometries, and with inconclusive results. The LRO Mini-RF utilizes new wideband hybrid polarization architecture to measure the Stokes parameters of the re- flected signal. These data will help to differentiate “true” volumetric ice reflections from “false” returns due to angular surface regolith. Additional lunar science investigations (e.g. pyroclastic deposit characterization) will also be attempted during the LRO extended mis- sion. LRO’s lunar operations will be contemporaneous with India’s Chandrayaan-1, which carries the Forerunner Mini-SAR (S-band wavelength and 150-m resolution), and bistatic radar (S-Band) measurements may be possible. On orbit calibration, procedures for LRO S. Nozette · P. Spudis Lunar and Planetary Institute, 3600 Bay Area Blvd, Houston, TX 77058, USA B. Bussey ( ) · R. Jensen · K. Raney · H. Winters Applied Physics Laboratory, Laurel, MD 20723, USA e-mail: Ben.Bussey@jhuapl.edu C.L. Lichtenberg Naval Air Warfare Center, China Lake, CA 93555, USA W. Marinelli · J. Crusan · M. Gates National Aeronautics and Space Administration, Washington, DC 20546, USA M. Robinson Arizona State University, Tempe, AZ, USA