A15_SMSS_71_M016935_006                                                   
                                                                              
    Apollo 15 Soil Mechanics                                                  
    Lunar Self-Recording Penetrometer (LSRP) Page A-2                         
                                                                              
    Plot of Penetration vs. Stress, Index No. 3 (second test)                 
                                                                              
    The hand-drawn plot shows the stress applied at the penetrometer tip as   
    a function of depth of penetration as recorded on the lunar drum.         
                                                                              
    All six Apollo 15 penetrometer runs were done at station 8 near the end   
    of the second EVA (extra-vehicular activity) on 1 August 1971.  Station   
    8 was next to the ALSEP site, which was centered at 26.1341 N latitude,   
    3.6298 E longitude, roughly 110 meters WNW of the LM.  All runs were      
    done using flight unit S/N 2003, lunar drum S/N 2002.                     
                                                                              
    Lunar Module pilot James Irwin performed the penetrometer runs after      
    digging a roughly 40 cm deep trench.  He started the measurements at      
    index 2 on the penetrometer. This run (second run, index 3) was done in   
    the bottom of the trench using the 3.226 square cm (0.5 square inch)      
    cone. It was performed at 18:03:30 UT according to the notes on pages     
    C-2 and C-3 (A15A_smss_71_m016935_019 and _020).  On the plot, stress is  
    given from 0 to 40 Newtons per square centimeter and penetration from 0   
    to 25 centimeters, both on a linear scale.  The plot is based on data     
    from the Lunar Penetration Data Reduction Table for index 3 (Page B-2,    
    A15A_smss_71_m016935_012).