Abstract

We owe NASA’s Apollo program much of what we know about the geology of the Moon. It was not only the rock samples the astronauts returned with, but also the scientific instruments they deployed on the Moon. The very first set of instruments deployed at the Apollo 11 site was solar-powered and lasted for 20 earth days. The instrument packages deployed at Apollo 12, 14, 15, 16, and 17 were powered by radioisotope thermal generators, and they operated continuously from the time of deployment (1969-1972) to 1977 and transmitted data to the Earth. These instrument systems were collectively called the Apollo Lunar Surface Experiments Packages (ALSEPs), and they included seismometers, magnetometers, heat flow probes, etc. The ALSEP data were processed at the NASA Johnson Space Center in Houston, and then were recorded digitally on open-reel magnetic tapes. Forty years later, these datasets remain to be the only direct, long-term, geophysical observations made on the surface of an extra-terrestrial body.

In the closing years of the Apollo program in the mid-1970s, funds necessary for processing ALSEP data still arriving from the Moon were terminated prematurely for many of these experiments. As a result, some of the data were left unprocessed or not archived. In the following decades, the people involved in the ALSEP program moved on to other things, retired, or deceased. Many of the magnetic tapes which stored the original data became lost in that process. In 2009, the ALSEP Data Recovery Focus Group was founded at NASA’s Lunar Science Institute, and was put to the task of restoring such missing ALSEP data and archiving them in NASA’s Planetary Data System. This presentation reviews the Group’s recent progress in locating data tapes and assembling metadata archives, along with examples of how modern scientists continue to extract new knowledge about the Moon by examining/re-examining the ALSEP data with highly advanced computers and new analytical techniques.