| DATA_SET_DESCRIPTION |
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.
Data
====
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
http://history.nasa.gov/alsj/) 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.
Videos
------
Most of the index runs of the penetrometer were captured on video
with audio and are included in the DOCUMENT directory.
Photography
-----------
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.
Transcript
----------
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.
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