http://en.wikipedia.org/wiki/LOIRP
(...)
"The images taken by the Lunar Orbiter spacecraft were primarily used to locate landing sites for the manned Apollo missions. Once those missions were over, the data was largely forgotten since it had served its purpose. The original tapes were carefully archived for 20 years by the government in Maryland. When the tapes were released back to NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, in 1986, the decision of whether to scrap the tapes became the responsibility of JPL archivist Nancy Evans. She decided that the tapes should be preserved. She recalled, "I could not morally get rid of this stuff".[2]
"Within a few years, Nancy Evans and a few colleagues were able to start a small project with funding from NASA. They managed to find four rare Ampex FR-900 tape drives—highly specialized drives that had only been used by government agencies such as the FAA, USAF, and NASA. (The FR-900's transport was adapted from the 2" Quadruplex videotape format, only in the FR-900's case, the drive was designed to record a wideband analog signal of any type for instrumentation or other purposes, rather than specifically a video signal as in 2" Quad's case.) Over time, Evan's team also collected documentation and spare parts for the tape drives from various government surplus sources. The project was successful at getting raw analog data from the tapes, but in order to generate the images, they discovered that they needed the specialized demodulation hardware that had been used by the Lunar Orbiter program, which no longer existed. They attempted to get funding from NASA and private sources to build the hardware, but were unsuccessful. Eventually, both Nancy Evans and Mark Nelson went on to other projects while the tape drives sat in Nancy Evans' garage.[3]
"In 2004, Philip Horzempa was doing research on the Lunar Orbiter program at the NASA History Office in Washington, D.C. In the archives, he happened to come across a memo from 1996 containing a proposal by Mark Nelson to digitize the Lunar Orbiter images, as described above...."
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