Several contemporary efforts, including the Lunar Orbiter Image Recovery Project (LOIRP) , are reanalyzing old Apollo-era data and getting surprisingly better results using modern tools and techniques. These new results are inspiring the Lunar Science Community to refine old estimates to gain a better understanding of the lunar environment.

For example, the number of deep moonquakes observed by original investigators 35 years ago was ~1,300, but now using modern advanced analysis techniques on the old Passive Seismic Experiment data, current investigators estimate ~7000 moonquakes were recorded by the Apollo Lunar Surface Experiments Package (ALSEP).

ALSEP comprised a set of scientific instruments placed by the astronauts at the landing site of each of the five Apollo missions to land on the Moon following Apollo 11. The instruments were designed to run autonomously after the astronauts left and to make long term studies of the lunar environment. They were arrayed around a Central Station which supplied power generated by a radioisotope thermoelectric generator (RTG) to run the instruments and communications so data collected by the experiments could be relayed to Earth. Data collected from the instruments were converted into a telemetry format and transmitted back to Earth.

Apollo 12 ALSEP

ALSEP Experiment Data Operations
Five ALSEP systems were deployed by Apollo 12-17, and all ALSEPs systems operated satisfactorily until End-of-Mission turn-off on September 30, 1977. Downlinked ALSEP data was recorded on tape at various 30-meter antenna ground stations. Tapes were shipped to the Experiments Operations Room (EOR) at JSC, which provided command capability and limited real time display of raw data. At EOR, each experiment’s data was stripped off and the experiment’s data tapes were sent out to each experiment PI. All daily data from each ALSEP system was recorded on an ALSEP system data tape ARCSAV and saved (there were over 11,000 system tapes total). As a money saving change, the tape handling effort was transferred to University of Texas in Galveston on March 1, 1976.

JSC ALSEP Experiments Operations Room

Much of ALSEP Data in Goddard Space Flight Center’s (GSFC) National Space Science Data Center (NSSDC) is currently very difficult to use due to archaic formats and anomalies introduced by a 7 to 9 track tape conversion process. Researchers trying to track down the ALSEP data estimate that up to 50 percent of ALSEP “Data of Interest” was not in NSSDC archives. The data presumably exists, but where is it? Who might still have back-up copies today?

Recovering the ALSEP data has taken on a sense of urgency, similar to the LOIRP project, as many of the original Principal Investigators (PIs) and team members are deceased, retired, or unavailable.

Originally the PIs were instructed to archive all the raw, processed and intelligible experiment data. Several factors complicated what actually happened. First, ALSEP experiments continued to operate for many years beyond their original mission lifetime. Some instruments with failures continued to collect data for years, so there is good and bad data to sort through. When funding was rapidly ramped down after EOM, many scientists made value judgments as to what data was best and “scientifically important.” Either they did not analyze all the data, or they provided the archives with only the data that was important to their investigations at the time. When funds were low, sometimes no data at all were sent to the archives.

Recent Successes
* Recent Discoveries at LPI Library. Lynn Lewis and Dave Williams of NSSDC, visited the LPI Library on 3-4-10 and discovered a non-cataloged assembly of ALSEP documents containing a complete set of weekly ALSEP (Operational) Performance Summary Reports from 1969 to 1977. These reports documented shipments of ALSEP data and ALSEP system data tapes ARCSAV to NRC-Fort Worth listing NRC box numbers. These box numbers will be crucial to searching the NSSDC archives for additional data. The documents also contained a large number of reports on testing, analyses, anomalies, memos, command logs, performance summaries, possible system and experiment “Rosetta stones,” and sunrise, noon, sunset, and midnight data for all ALSEP locations.

*LSM -Lunar Surface Magnetometer. Communication at NLSI’s Lunar Science Forum I &II between Palmer Dyal, LSM PI, and Peter Chi, a current investigator from UCLA, has resulted in LSM materials in NRC being turned over to NSSDC and Chi.

*HFE-Heat Flow Experiment. Pat Taylor’s (GSFC) LASER project was approved to recover Heat Flow Data from Lamont-Doherty Geophysics Lab.

*Columbia Dust Detector. At the 41 LPSC XLI ALSEP Data Side Meeting in early March 2010 it was determined that from the ALSEP central station data Yosio Nakamura had in support of PSE, all the raw Dust Detector data from Apollo 11 to Apollo 15 could be recreated in a digital format. Dave Williams, NSSDC, indicated he could generate the simple “Rosetta stone” needed. This will be much less costly than scanning and digitizing the current microfiche records.

Scientists are reviewing and updating the current catalogue of missing ALSEP data from NSSDC charts and tables. By contacting experiment PI’s and team members where data are believed to be missing, and by following up on recently discovered documents, they hope to update predictions of missing ALSEP data-of-interest.

Stay tuned as we will periodically post announcements as to the progress of efforts to recover missing ALSEP data and its current and projected availability.

Posted by: Soderman/NLSI Staff
Source: Lynn Lewis: Lewis, Lynn R. et al, Lunar Science Conference I, Abstract #2035 and #2022, July 2008.

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