Lunar Reconnaissance Orbiter Science Targeting Meeting (2009) 6041.pdf

JOINT LROC – MINI-RF OBSERVATIONS: OPPORTUNITIES AND BENEFITS . S. Nozette1, D.B.J. Bussey2, B. Butler3, L. Carter4, J. Gillis-Davis5, J. Goswami6, E. Heggy7, R. Kirk9, T. Misra6, G.W. Patterson2 , M. Robinson8, R. K. Raney2, P. D. Spudis1, T. Thompson7, B. Thomson2, E. Ustinov7 1. Lunar and Planetary Institute, Houston TX 77058 (Stewart.Nozette-1@nasa.gov) 2. Applied Physics Laboratory, Laurel MD 20723 3. NRAO, Socorro NM 4. NASM, Wash- ington DC 5. Univ. Hawaii, Honolulu HI 96822 6. ISRO, Bangalore, India 7. JPL, Pasadena CA 8. ASU, Tempe AZ 9. USGS, Flagstaff AZ

Introduction: Mini-RF is a lightweight Synthetic is also dark in radar reflectivity, exactly what would be Aperture Radar (SAR) instrument set to fly on the Lu- expected from a fine-grained, block-free deposit. Mini- nar Reconnaissance Orbiter (LRO). A sister instrument SAR radar images confirm the geological interpreta- is currently imaging the Moon aboard the Indian tion first derived in 1994 from Clementine images. Chandrayaan-1 spacecraft. Mini-RF on LRO has three Additional observations will benefit from higher reso- primary functions:- 1. Communications demonstration. lution LROC and Mini RF images acquired in a coor- 2. SAR-mapping. 3. Interferometric mapping. dinated manner. Mini RF measures the properties of the lunar rego- The goal of Mini-Rf on LRO during the scince- lith at two wavelength scales; S band (12cm) and X driven extemded mission is to image areas of scientific band (3 cm) and at two spatial resolutions, 150 meters interest, such as pyroclastic deposits. Co-ordinated and 30 meters. studies using targeted-data of other LRO instruments LRO-LROC Operations: Mini RF and LROC share will enhance the scientific return. common LRO spacecraft support assets (e.g. power, bandwidth) which requires operating one of the two instruments at any given time. Mini-RF can operate during periods when LROC observations are not use- ful, for example during dawn-dusk orbits with low sun angles or when LRO is traversing above the unillumi- nated lunar surface. In addition to the planned Mini- RF observations of the permanently shadowed polar regions, additional Mini-RF observations may be pos- sible of scientifically interesting non-polar areas during the LRO primary and extended missions. Joint plan- ning of these observations with LROC should be ex- plored. Such planning will produce operational bene- fits allowing for a more streamlined Mini-RF com- manding, data collection and distribution, and provide unique science observations. Non-Polar Targets: Mini RF probes beneath the sur- face at scales comparable to each wavelength. The size and distribution of surface and subsurface blocks, regolith bulk density, and in some cases regolith com- position may be inferred from Mini-RF data. When

combined with higher resolution LROC images addi- Figure 1. Mosaic of mini-Rf data covering a por- tional knowledge of regolith albedo, structure, and tion of Schrödinger basin, including the pyroclastic physical properties may be derived, leading to new vent. geologic insight and interpretation. This was recently demonstrated using data from LRO Mini-RF’s fore- runner, Mini-SAR on Chandrayaan 1. The location and distribution of pyroclastic deposits is a long-standing lunar science objective recently endorsed by the NAS. Mini-SAR obtained images of the Schrödinger impact basin (Figure 1). Schrödinger shows an unusual, key- hole-shaped crater along a long fissure on the basin floor. This crater is surrounded by optically dark mate- rial, which has been interpreted as volcanic ash depos- its. The new Mini-SAR image shows that this material