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Apollo 16 Surface Penetrometer Data - Digital Scans (LDP)


Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)

Time span: 1972-04-21 to 1972-04-24


These data have been scanned from microfilm as part of the Lunar Data Project (LDP) and are available online as jpeg images.

The soil mechanics data consist of handwritten plots, tables, and notes from the self-recording penetrometer carried on the Apollo 15 mission. The Stress vs. 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, which are taken from the penetrometer drum returned to Earth. These tables give mission, date, flight unit, lunar drum, index number, and notes on the cone or plate used. The table columns give the drum load 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 labelled 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 31.5 (index2, Apollo 15) On some tables there is a final column, headed "+correction add 3.75", which is the previous column with a 3.75 cm correction added. This is a correction for the additional length of the cone attached to the bottom of the penetrometer rod on Apollo 15, it does not appear on the Apollo 16 tables.

The sets of handwritten notes give times and notes 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. One line shows the deadweight load and a parallel line shows the correction for the weight of the penetrometer. The latter is the line used for the calibration. The plot is based on a pair of post-flight calibration tables. The first table, "load calibration" gives the index number, the "vert. scribe", which looks to be the starting point of the drum rotation for a given index run, and columns giving the load in kilograms and Newtons. All values are given in degrees and minutes. The top value in a cell is the actual reading and the lower value is the reading minus the vert. scribe value, which would represent the drum deflection. The second table, "penetration calibration", gives the readings in cm for a given position and index number. There is also a pre-flight calibration plot which gives the load in Newtons versus the drum circumferential deflection in mm with a 2 sigma error line on each side of the calibration line.

The Apollo 15 frames are named in the form A15A_smss_71_m016935_nnn, where A15A denotes Apollo 15, smss is for soil mechanics, 71 is the year, m016935 is the microfilm reel, and nnn is the frame number for that reel and mission. The Apollo 16 frames are A16A_SMSS_72_m016936_nnn. A few of the frames have parts that are difficult to read because they were not clear on the microfilm. These are Apollo 15 frame 20 and Apollo 16 frames 30, 43, and 44. In most cases the numbers can be read with some difficulty or calculated from the surrounding values.

Browse images with links to jpeg versions of the scans are available online at:

These scans are also available as validated PDS data sets at:

Alternate Names

  • Surface Penetrometer Digit. Scans


  • 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
Prof. James K. MitchellGeneral ContactUniversity of California, Berkeley

Soil Mechanics Data/Information at NSSDCA

Scanned Soil Mechanics Data On-line (Browse images, text files, and jpgs)
Scanned Soil Mechanics Data (Preliminary jpegs and text files)

Apollo 15 Soil Mechanics (Digitized)
Apollo 15 Soil Mechanics (Microfilm)
Apollo 16 Soil Mechanics (Digitized)
Apollo 16 Soil Mechanics (Microfilm)

Related Information at NSSDCA

Apollo landing sites and ALSEP and LRRR locations - and information on the modified DMA/603 control network

Lunar Data Project
Apollo Home Page

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