Detecting lunar lava tubes by a landing mission with the Ground Penetrating Radar :
Authors: Miyamoto, H. H.; Haruyama, J.; Nishibori, T.; Rokugawa, S.
American Geophysical Union, Fall Meeting 2002, abstract #P71A-0439
The following is a short list of references based on Richard Perry's paper on Lunar lava tubes and site selection.
ref 1.1: Apollo 15 metric camera image, shows the collapsed lava tubes referred to in the article.
ref 2.1.1 Atlantis SAR page: Earthview SAR Processor
ref. 2.2 Ground Penetrating Radar (GPS) pages: At Coumbia University: Ground Penetrating Radar (GPR) page: Excellent links page, probably the best you will find for information on GPR. At Ohio State University: GPR Homepage
ref. 2.3 Other GPR links pages:
ref. 2.4 An interesting page of reference papers into subsurface feature detection using radar, electromagnetic pulse etc. The papers may not be on the web however. Try going up from this url at Ohio State University to find out if there is anything else. The paper quoting these references was for unexploded ordinance detection.
ref. 2.5 The University of Arkasas Centre for Advanced Spatial Technologies (CAST): May be of some use for educational information with respect to remote sensing. Several tutorials.
ref. 2.6 The SIR-C/X-SAR Satellite Homepage. (broken) Possible replacement http://www.ifm.uni-hamburg.de/~wwwrs/rs.html
ref. 2.7 Chicxulub crater. The "dinosaur killer crater". The crater was detected in limestone, 300-1000m below surface using SIR-C/X- SAR imaging.
ref. 2.8 RadarSat I : Homepage of the SAR equipped Canadian space probe RadarSat I at Ball Aerospace..
ref. 2.11 Blackhawk resevoirs: information on a project to detect gas reservoirs using seismic techniques. A gas reservoir is still a void in rock, so this might contain something useful.
ref. 2.12 http://luna.geol.niu.edu/pjc.html (broken) : Page from a geophysist who quotes subsurface detection of voids as a personal research area.
ref. 2.13 a proposed lava tube mapping instrument, a SMIFTS (Spatially Modulated Imaging Fourier Transform Spectrometer.) This is the current limit of data processing, which claims to be able to identify evidence of subsurface cavities from data sets. Would be just the thing as a lunar tool.
ref. 2.14 Undara Lava Tubes
Site of the largest hollow lava tubes on Earth,located in Northern Australia.
ref. 2.15 Rille images from Clementine This page is operated by the French space agency, CNES. It picks out rille images from the Clementine dataset. (Hadley Rille is at 26.1°N, 3.7°E)
ref. 2.17 Schroter's Valley: Info from U-N. Dakota. Collapsed lava tubes may also have un-collapsed side-channels from them. The largest such feature is Schroter's Valley and the Aristarchus Plateau. It lies between Mare Imbrium and Oceanus Procellarum and being so large, it is not only likely to have more tributaries, but access should be easier.
ref. 2.18 Posidonius Rille: Offers a crater location which has seen several stages of volcanic activity. Thus, the area was once very active, and is likely to have a reasonably flat landing site. Whether older cavities were infilled by later flows is probable, but this could still leave some unfilled.
ref. 2.19 Marius Hills: This is a very volcanic region, and likely to have a large concentration of stable lava tubes.
ref. 2.20 A oft-quoted scientific reference is Wilhelms (1987) The Geologic History of the Moon, USGS Prof. Paper 1348, but no online version has yet been located by this author.