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 its properties in lateral and vertical directions, on slopes, and between different regions of the Moon.  The equipment used included an adjustable sampling scoop, a self-recording penetrometer, core tubes, and the Apollo lunar surface drill and bore stems.  Further soil testing could be done at LRL in Houston on returned soil samples, including the core tube and other geologic samples, especially the fine-grained soil sample.  Photography requirements of this experiment were met with a battery-operated 16-mm data acquisition camera (DAC) with a 10-mm focal length lens, a Hasselblad electric data camera (HEDC) with a 60-mm focal length lens, and real-time TV transmissions.  The astronauts performed the required trenching activity, penetrometer load plate and cone tests, and soil behavior/characteristic observations such as the LRV wheel/lunar soil interaction and LM footpad/soil interaction.  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.

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 its properties in lateral and vertical
    directions, on slopes, and between different regions of the Moon.  The
    equipment used included an adjustable sampling scoop, a self-recording
    penetrometer, core tubes, and the Apollo lunar surface drill and bore
    stems.  Further soil testing could be done at LRL in Houston on
    returned soil samples, including the core tube and other geologic
    samples, especially the fine-grained soil sample.  Photography
    requirements of this experiment were met with a battery-operated 16-mm
    data acquisition camera (DAC) with a 10-mm focal length lens, a
    Hasselblad electric data camera (HEDC) with a 60-mm focal length lens,
    and real-time TV transmissions.  The astronauts performed the required
    trenching activity, penetrometer load plate and cone tests, and soil
    behavior/characteristic observations such as the LRV wheel/lunar soil
    interaction and LM footpad/soil interaction.  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 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 215 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 16 Soil Mechanics dataset. A16L-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.
 
    Eleven tests were made using the SRP during the second Apollo 16 EVA:
    four cone penetration tests at station 4 and five cone penetration and
    two plate load tests in the station 10 ALSEP area.  Double core tube
    samples were taken from stations 4, 8, 10, and 10' and a single core
    tube sample from station 9, a total of over 6 kg of drive tube
    samples.  A deep drill core was taken to a depth of 2.24 m in the ALSEP
    area.  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.
 
    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 16 LM Lunar Self-Recording Penetromter

Description

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