The Self-Recording Penetrometer facilitated the soil mechanics experiment, which was designed to obtain data on the characteristics and mechanical behavior of the lunar soil at the surface and subsurface and the variation of these properties in a lateral direction. Additional objectives were to aid in the interpretation of data obtained from other surface activities and experiments and to develop lunar surface models to help in the solution of engineering properties associated with future lunar exploration.

Instrument Overview
  ===================
    The Self-Recording Penetrometer facilitated the soil mechanics
    experiment, which was designed to obtain data on the characteristics
    and mechanical behavior of the lunar soil at the surface and
    subsurface and the variation of these properties in a lateral
    direction.
 
    Additional objectives were to aid in the interpretation of data
    obtained from other surface activities and experiments and to develop
    lunar surface models to help in the solution of engineering properties
    associated with future lunar exploration.  The equipment for the
    experiment included a sampling scoop, a self-recording penetrometer
    with interchangeable load plate and cones of various diameters, core
    tubes, and the Apollo lunar surface drill.  From lunar samples (such
    as core tube samples and other geological samples, especially the
    fine-grained soil samples) obtained by the lunar geology experiment,
    further soil mechanics data was derived by testing in the Lunar
    Receiving Laboratory (LRL).  The photographic equipment used for this
    experiment included a battery-operated 16-mm Maurer data acquisition
    camera (10-mm lens) and a Hasselblad electric data camera (60-mm
    lens).  Television was also used in a real-time support role. The
    astronauts performed the required trenching activities, penetrometer
    load plate and cone tests, and soil behavior characteristics
    observations in the Hadley-Apennine area.
 
    The Lunar Self-Recording Penetrometer (LSRP) had a mass of 2.3 kg and
    consisted of an upper cannister housing attached to the top of a long
    shaft and a reference pad assembly attached to the bottom.  A
    recording drum was contained in the upper cannister and captured a
    record of each penetration.  The LSRP was equipped with a 2.54 x 12.7
    cm bearing plate and three penetrating cones with base areas of 1.29,
    3.22, and 6.45 square cm and a 30 degree apex angle that could be
    attached to the bottom of the penetration shaft at the reference pad.
    The reference pad, which folded for storage, acted as a datum on the
    lunar surface for measurement of penetration depth.  When an astronaut
    pushed on the upper end, the bearing plate or lower cone and shaft
    would penetrate into the lunar soil while the reference pad stayed on
    the surface.  A retractor cable mechanism running from the reference
    pad to the upper housing actuated a stylus which would move axially
    along the recording drum to measure the depth of penetration.  The
    force applied through the extension handle by the astronaut would
    deflect a calibrated coil spring which would cause the recording drum
    to rotate under the stylus by an amount proportional to the force.
    The maximum force caused a 30 degree rotation.  The LSRP had a maximum
    penetration depth of 76 cm and the ability to measure penetration
    force to a maximum of 111 Newtons.  After each run, the astronaut
    would manually advance an index register to a new number.  The surface
    reference pad had a tendency to ride up the penetrometer shaft slightly
    if the LSRP was vibrated after the initial indexing and positioning.
    This was due to the friction between the reference pad brushing and
    shaft being less than anticipated and had a small effect on the
    readings, which is described in the DATASET.CAT file of the archived
    Apollo 15 Soil Mechanics dataset. A15L-L-LSRP-2/3-SOIL-MECHANICS-V1.0.
    After tests were completed, an astronaut removed the head from the
    penetrometer and stowed it for return to Earth.  This head contained
    the recording drum that indicated the penetrometer test results.
 
    The core tubes were thin-walled hollow aluminum tubes, 37.5 cm long
    with an inside diameter of 4.13 cm and an outside diameter of 4.38 cm.
    The lower tubes could be used individually or screwed together with an
    upper tube to make a longer, or double, tube.  The lower tube had a
    stainless steel bit on the bottom for penetrating the soil.  A
    'keeper', a flat disk with the same inside diameter as the tube, fit
    inside the top end of the tube and an adapter was screwed on top.  The
    tubes would be driven into the ground with a hammer as far as they
    could go.  Then the keeper would be pushed down inside the tube by a
    long rod which fit into a hole in the top of the adapter.  The keeper
    would be pushed to the top of the sample in order to keep the sample
    in place.  The tube was then removed from the ground, the end covered
    with a teflon cap, and the sample was brought back to Earth for
    analysis.
 
    The Apollo lunar surface drill consisted of an electric drill with a
    set of long hollow bore stems which could be screwed together.  The
    top of the drill had a battery pack and handle, directly underneath
    this was a power head and thermal shield.  The drill stem extended
    from this through a treadle placed on the surface and into the
    regolith.  At the bottom of the first drill stem was a 6 cm long drill
    bit with five tungsten-carbide blades.  The drill was used to retrieve
    deep samples (down to 4.6 meters) of lunar regolith.
 
    On the Apollo 15 mission, one soil trench was excavated at the ALSEP
    site with a near-vertical face of approximately 28 cm and another at
    station 6.  The self-recording penetrometer was used near the ALSEP
    site for four cone penetration tests and two plate load tests.  The
    core tubes were used in three locations to collect a total sample of
    3302 grams.  A single tube was used at station 6 and two double tubes
    were used at stations 2 and 9A.  A drill hole sample was taken on the
    second EVA near the ALSEP site.
 
    This instrument description was provided by the NASA National Space
    Science Data Center.

extracted metadata from PDS3 catalog and
                    modified to comply with PDS4 Information Model

Apollo 15 LM Lunar Self-Recording Penetrometer

Description

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