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Availability: Archived at NSSDC, accessible from elsewhere

Time span: 1972-04-19 to 1972-05-12


This description was generated automatically using input from the Planetary Data System.

Data Set Overview

This dataset contains tables of raw readings and reduced data from ten runs on 22 April 1972 of the Lunar Self-Recording Penetrometer (LSRP) on the surface of the Moon for the Apollo 16 Soil Mechanics experiment. Supporting documentation includes digitized scans in JPEG and PDF format of the original LSRP soil mechanics dataset on microfilm, videos and transcripts of the LSRP as it was operated on the Moon, diagrams and maps of the experiment areas, and photography of Apollo 16 Stations 4 and 10 where the experiment was performed. The Apollo 16 penetrometer runs were done near Station 4, Bench Crater, and Station 10, the ALSEP site. The runs were performed near the end of the second EVA (extra-vehicular activity) on 22 April 1972. The flight unit S/N 2004 and lunar drum S/N 2008 were used for all runs. The drum was returned to Earth and the etchings made by the penetrometer were read and recorded on hand-written charts by the investigators. Copies of the charts were sent to the National Space Science Data Center (NSSDC), where they were microfilmed and archived. For more information about the experiment see the Chapter 8 of the Apollo 16 Preliminary Science Report, which is provided in the DOCUMENT directory.


The raw readings and reduced data from each of the ten runs of the penetrometer are provided as fixed-width ASCII text tables and are reproductions of the lunar penetration data reduction charts, in the handwritten LSRP report, which were taken from the penetrometer drum returned to Earth. (The handwritten report was scanned from the microfilm archived at the NSSDC.) The tables are named in the form A16_SMSS_72_M016936_nnn.TAB, where A16 denotes Apollo 16, SMSS is for soil mechanics, 72 is the year of data acquisition, M016936 is the microfilm reel, and nnn is the sequential frame number corresponding to a page that contained the data chart in the report. Each table (*.TAB) is accompanied by an ASCII text file (*.TXT) that provides the header records for that data chart. Each table and header combination is described by a detached PDS label. The header records contained in the *.TXT file for a data table give the mission, date, flight unit, lunar drum, index number (from 5 to 16 and designating penetrometer runs 1 to 11), and notes on the cone or plate used. The columns in the data records of a table give the drum load (the angle of deflection of the stylus on the drum) in degrees/minutes, the drum load in decimal degrees, the drum circumference deflection in millimeters (decimal degrees multiplied by .5542), the load in Newtons (calculated from a calibration curve), and the stress in Newtons per square centimeter (load divided by the cone or plate base area). This is the value plotted for stress on the plots. A second set of columns starts with a column labeled initial drum depth/final in cm and gives a running total of the drum reading. The next column, delta Drum Depth Reading in cm gives the difference between the current drum depth reading and the previous value. The next column, penetration depth in cm, is the drum depth reading multiplied by 31.3 (index 5, Apollo 16). The ten penetrometer runs and associated tables in the DATA directory are described below. The Mission Elapsed Time (MET) and UT values were taken from the Apollo Lunar Surface Journal (ALSJ at because the values were not available in the mission notes. The index numbers are from the handwritten LSRP report; index 5 is the first one that is available and is assigned run number 1. Station 4, Bench Crater Run 1 - Index 5** - A16_SMSS_72_M016936_017.TAB Uphill, south of rover, top part of crater 18:24:05 UT, 144:30:05 MET Run 2 - Index 6 - A16_SMSS_72_M016936_019.TAB Few meters south of rover near edge of crater 18:27:00 UT, 144:33:00 MET Run 3 - Index 7 - A16_SMSS_72_M016936_021.TAB Few meters SW of rover near edge of crater 18:28:12 UT, 144:34:12 MET Run 4 - Index 8 - A16_SMSS_72_M016936_022.TAB Downhill, north of rover, next to double-core tube site 18:29:24 UT, 144:35:24 MET ** Indexes 1 through 4 skipped, started on 5 Station 10, ALSEP Site Run 5 - Index 10** - A16_SMSS_72_M016936_024.TAB 23:00:48 UT, 149:06:48 MET Run 6 - Index 11 - A16_SMSS_72_M016936_026.TAB Using 0.2 tip, next to last penetrometer hole 23:03:39 UT, 149:09:39 MET (very approximate) Run 7 - Index 12 - A16_SMSS_72_M016936_028.TAB Fourth of the way from the rover to the deep core site, using 0.2 tip 23:04:45 UT, 149:10:45 MET (very approximate) Run 8 - Index 13 - A16_SMSS_72_M016936_030.TAB Halfway between rover and deep core site, using 0.2 tip 23:05:50, 149:11:50 MET (very approximate) Run 9 - Index 14** 2 to 4 meters towards central station, using 0.2 tip Run 10 - Index 15 - A16_SMSS_72_M016936_031.TAB Using flat plate, near the double core 23:11:20 UT, 149:17:20 MET (very approximate) Run 11 - Index 16 - A16_SMSS_72_M016936_032.TAB Using flat plate, a couple of meters away 23:11:45 UT, 149:17:45 MET (very approximate) ** Index 9 skipped; Index 14 is listed in the ALSJ but the corresponding data chart is not in the handwritten LSRP report.

Known Problems with Penetrometer Runs

According to the Apollo 16 Preliminary Science Report [APOLLO16A1972] there were some problems with the lunar reference plane riding up the penetrometer shaft after initial indexing and positioning. This resulted in an intercept for zero stress on the penetration axis from 1.9 to 9.0 cm. The penetration curves will therefore not represent soil conditions above the intercept point, but are correct below it.

Supplementary Information

The DOCUMENT directory contains supplementary information about the Soil Mechanics experiment, including the following items.

Handwritten LSRP Report

In addition to the data tables, it is important to note that the handwritten LSRP report includes hand-drawn plots and notes from the experiment. The Stress versus Penetration plots give the stress in Newtons per square centimeter versus the penetration depth in centimeters on a linear scale. These are plotted from the data in the lunar penetration data reduction tables found in the report and in this dataset. A few of the frames, such as 43, have sections that are difficult to read because they were not clear on the microfilm. In most cases the information can be read with some difficulty or calculated from the surrounding values. Additionally sets of handwritten notes in the LSRP report give information on the sampling locations and other aspects of the sampling, including diagrams. The Post-Flight Calibration plots give load in Newtons versus drum circumferential deflection in mm. The first plot shows calibrations based on 12 preflight measurements and postflight calibrations before and after washing. The second plot gives the postflight penetration calibration of drum movement versus actual penetration. The next four tables give the numbers used to make these plots. The Pre-Flight Calibration section has the load versus deflection for the 12 pre-flight calibration runs and an enlarged detail of the table which was very faint. The detail includes values which were filled in by enlarging the scans and using the legible values on the chart.

Site Diagrams, Maps, and Images

The DOCUMENT directory contains several diagrams and maps of the experiment areas including high resolution images taken by the Lunar Reconnaissance Orbiter Camera of the entire Apollo 16 area and the landing site, Station 4, and Station 10.


Most of the index runs of the penetrometer were captured on video with audio and are included in the DOCUMENT directory.


Still photos were taken for the Soil Mechanics experiment and are included in the DOCUMENT directory. Most of the photos apply to the index runs performed at Station 4, Bench Crater. One panoramic view of the Station 10 ALSEP site is included.

Annotated Photography of Station 4 Sample Sites

The DOCUMENT directory includes annotated photos taken by the astronauts and one mosaic of the site of the four index runs Soil Mechanics experiment at Stations 4.


Transcripts of the recorded audio commentary as the astronauts performed the experiment at Apollo 16 Stations 4 and 10 are included in the DOCUMENT directory.

These data are available on-line from the Planetary Data System (PDS) (under 'Lunar Self-Recording Penetrometer') at:

Alternate Names



  • Planetary Science: Geology and Geophysics

Additional Information



Questions and comments about this data collection can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. David R. WilliamsGeneral ContactNASA Goddard Space Flight
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