urn:nasa:pds:a17tg_traverse_gravity:data:a17_traverse_gravity_data 1.0 1.23.0.0 Product_Observational 2025 This table contains data from the Apollo 17 Traverse Gravimeter experiment. Columns 1, 2, 3, 4, 6, 10, 11, 12, 13 and 14 are from page 67, Table 11-1 of the principal investigator's Traverse Gravimeter Experiment Final Report by Buck, et al., (1973). Other information in the table was taken from the Apollo 17 Preliminary Science Report and from the Apollo Science Experiments Data Handbook. The absolute value for the Lunar Module site was estimated to be 162,694.6 milligal with an uncertainty of 5 milligal. (One gal or galileo is defined as 0.01 meters per second-squared.) For a summary of errors assumed, see table 9-1, page 57 in Buck, et al. (1973) included in the DOCUMENT directory. Based on knowledge of the instrument and the measurements it was assumed the instrument drift was negligible. The root-mean-square instrument noise value was given as 1.8 milligal based on values taken with the instrument off the Lunar Roving Vehicle at the Lunar Module site (readings 3, 9, 11, 17, 19, and 25). To convert the difference in the display readings to milligal, the higher order terms in the equation were neglected and the reading difference was simply multiplied by -0.03245. For more details see Chapter 13, Traverse Gravimeter Experiment, of the Apollo 17 Preliminary Science Report included in the DOCUMENT directory. 2025-08-13 1.0 Initial version. 1972-12-12T01:12:21Z 1972-12-14T04:28:48Z Apollo 17 Mission urn:nasa:pds:context:investigation:mission.apollo_17 data_to_investigation Apollo 17 Lunar Module Host urn:nasa:pds:context:instrument_host:spacecraft.a17l is_instrument_host Apollo 17 Lunar Module Traverse Gravimeter Instrument urn:nasa:pds:context:instrument:tg.a17l is_instrument Moon Satellite urn:nasa:pds:context:target:satellite.earth.moon data_to_target a17_traverse_gravity_data.tab 2011-11-01T13:00:00Z

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TABLE 420 26 Carriage-Return Line-Feed 18 0 210 READING_NUMBER 1 1 ASCII_Integer 2 Reading number in chronological order from 1 to 26 EVA_NUMBER 2 5 ASCII_Integer 1 Number of the extravehicular activity (EVA) during which the measurement was made, one for each day of the surface mission SITE 3 8 ASCII_String 6 An abbreviation that identifies the site where the measurement was made: ALSEP = Near the ASLEP site LM = Near the Lunar Module (LM) SEP = At the site of the Surface Electrical Properties experiment, roughly 100 meters from the LM Sta.N = At Station number N, for example Sta.3 = Station 3 For a map of the traverse gravimeter sites, see figure 11-2, page 29 of the Traverse Gravimeter Experiment by Buck, et al. (1973) included in the DOCUMENT directory. TG_DISPLAY_READING 4 16 ASCII_String 10 Actual raw reading taken off the traverse gravimeter display. This was a nine-digit number, the first three digits gave the state of the reading (670 normal, 337 inverted, 000 invalid reading), the next 4 digits gave the raw gravity reading, and the final two digits gave the thermal code. For an explanation of the thermal codes see table 7-2, page 45 of the Traverse Gravimeter Experiment Final Report by Buck, et al. (1973) [BUCKETAL1973] included in the DOCUMENT directory. Readings 1, 10, and 18 were obtained to learn the thermal state of the instrument before the EVA periods; the TG_DISPLAY_READING for each of these readings is "xxxxxxx-0y". No gravity values were obtained with these three readings. ELAPSED_TIME_OF_READING 5 28 ASCII_String 7 Elapsed time of the measurement from the time the EVA was started to the time the button was pressed to start the reading. The EVA start times were: EVA1 - 11 December 23:54:49 UT EVA2 - 12 December 23:28:06 UT EVA3 - 13 December 22:25:48 UT The value of N/A or blanks indicates the elapsed time reading was not available. TYPE_OF_READING 6 37 ASCII_String 8 Identifies the type of reading: Inverted = BIAS on surface On LRV = GRAV on Rover Off LRV = GRAV on Surface Thermal = Temperature For detailed definitions of these reading types, see the instrument catalog file (CATALOG/INST.CAT) in this data set. DN_MINUS_DN_BASE 7 47 ASCII_Integer 5 Difference between the raw reading and the baseline reading. Reading 3 was the baseline (0 DN); it was the first surface reading taken near the LM site. -9999 DELTA_G 8 54 ASCII_Real 5 Milligal Raw difference in COLUMN 7 converted to milligal (delta g in milligal, 1 gal (galileo) = 0.01 meter/second-squared). The value was calculated by multiplying the difference in COLUMN 7 by -0.03245. -99.0 CORRECTED_BASELINE 9 61 ASCII_Real 5 Milligal DELTA_G corrected for the difference between measurements made while the gravimeter was mounted on the Lunar Roving Vehicle (LRV) and when it was directly on the surface. An empirical difference of 6 milligals was used based on 3 pairs of measurements made on the LRV and on the surface (readings 2-3, 21-22, and 23-24). This was subtracted from all on-LRV measurements to give an equivalent surface reading. -99.0 UPDATED_LM_DISPLAY 10 68 ASCII_String 8 Updated baseline reading. This reading was determined based on the assumption that each movement of the gravimeter from the rover to the ground resulted in unrecoverable upward bias shifts in the instrument. The bias shift was estimated based on ground tests of the flight spare and engineering model, and the results of the preliminary and close-out readings at the LM site for each EVA. The uncertainties are very large for the final readings because the final closeout measurement was considered unreliable. For more details see the instrument catalog file (CATALOG/INST.CAT) and the Traverse Gravimeter Experiment Final Report by Buck, et al. (1973) included in the DOCUMENT directory. GRAVITY_DIFFERENCE_DISPLAY 11 77 ASCII_Integer 5 DN Difference between the display reading and the updated baseline from column 10. -9999 GRAVITY_DIFFERENCE_DISPLAY_SIGMA 12 84 ASCII_Integer 3 DN The 2 sigma (95% confidence) uncertainty in the reading based primarily on the uncertainty in the updated baseline reading and effects of moving the gravimeter on and off the rover. -99 GRAVITY_DIFFERENCE_DISPLAY_MGAL 13 89 ASCII_Real 6 Milligal The gravity difference in milligal, computed by multiplying column 11 by -0.03245. -99.00 GRAVITY_DIFFERENCE_DISPLAY_SIGMA_MGAL 14 97 ASCII_Real 5 Milligal The 2 sigma value associated with column 13, multiplying column 12 by 0.03245. -9.00 NORTH_LATITUDE 15 104 ASCII_Real 5 Degree North latitude, in degrees, of the site given in column 3. The values are not part of the original experimental results but were added to the table to aid researchers. The values were taken (in 2012) from Lunar Reconnaissance Orbiter images using the GCS_Moon_2000 geographical coordinate system. EAST_LONGITUDE 16 111 ASCII_Real 5 Degree East Longitude, in degrees, of the site given in column 3. The values are not part of the original experimental results but were added to the table to aid researchers. The values were taken (in 2012) from Lunar Reconnaissance Orbiter images using the GCS_Moon_2000 geographical coordinate system. ELEVATION 17 118 ASCII_Integer 5 Meter Elevation calculated from topographic maps and other information available at that time of the original experimental analysis. The relative elevations, which are the values needed for relative gravity calculations, are probably reliable. -9999 COMMENTS 18 125 ASCII_String 84 Comments about the reading.