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Lunar Prospector Gravity: Spherical Harm. Models and Digital Map Data Archive (PDS)


Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)

Time span: 1998-01-11 to 1999-02-08


This data set contains an archive of the Lunar Prospector gravity data in the form of spherical harmonic models of the lunar gravity field and digital maps of the Bouguer anomalies, free-air gravity accelerations and errors, and geoid anomalies and errors. The data in this archive covers the one year Lunar Prospector nominal mission and the first 10 days of the 30 km average altitude orbit of the extended mission (11 Jan 1998 to 8 Feb 1999). The Lunar Prospector data were combined with S-band tracking observations from Lunar Orbiters 1, 2, 3, 4, and 5, the Apollo 15 and 16 subsatellites and Clementine to produce these models. The majority of the data used are from the Lunar Prospector observations.

There are two 75th degree and order spherical harmonic gravitational field models, designated LP75D and LP75G, and one 100th degree and order model LP100J for which the coefficients are available. Free-air, geoid, and Bouguer maps are also available for the LP75D and LP100J models. The LP75D model was a preliminary model containing LP data to 17 February 1998. The LP75G model was published in the special LP Science issue in September 1998 and contains data to 12 April 1998. The LP100J model includes all the LP Doppler and range data through 8 February 1999. This includes all the near 100 km altitude data (11 Jan 1998 to 19 Dec 1998), the data from the 40 km average altitude orbit (19 Dec 1998 to 29 Jan 1999) and the first 10 days of the 30 km average altitude orbit. Because of the Moon's synchronous rotation, spacecraft cannot be directly tracked from Earth over a large part of the lunar farside, so there is no tracking data from 120 to 240 degrees longitude in the +/- 70 degree latitude band. More models and maps will become available after the completion of the extended mission.

The data files are in 3 formats: array, image, and tabular. The array formats are 2-dimensional ASCII global grids of 180 lines by 360 samples (i.e. 1 degree resolution). There are images of each of the gridded ASCII data files. Each image is 180 lines by 360 samples, with one byte per sample. There are also 64-bit binary digital map images of the Bouguer anomalies, free-air gravity accelerations and errors, and geoid anomalies and errors. All the images are in a simple cylindrical map projection. Tabular files are formatted so that they may be read directly into many software analysis systems on various computers. All fields are separated by commas. The files containing the spherical harmonic coefficients of the Moon's gravity field (LP75D, LP75G, LP100J) are in tabular format, with each row in the table containing the degree index m, the order index n, the coefficients Cmn and Smn, and the uncertainties in Cmn and Smn. The images, files, and tables are described by detached PDS labels.

The data can be ordered through the NSSDC Request Office ( and is available online at:

Alternate Names



  • Planetary Science: Geology and Geophysics


  • 98-001A-04A

Additional Information



Questions and comments about this data collection can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Mr. Jim AlexopoulosGeneral ContactWashington

Selected References

  • Konopliv, A. S., et al., Improved gravity field of the moon from Lunar Prospector, Science, 281, No. 5382, 1476-1480, doi: 10.1126/science.281.5382.1476, Sept. 1998.
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