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Clementine S-Band Transponder Doppler Gravity Experiment

NSSDCA ID: 1994-004A-08

Mission Name: Clementine
Principal Investigator:Dr. Eugene M. Shoemaker

Description

The Clementine gravity experiment used measurements of perturbations in the motion of the spacecraft to infer the lunar gravity field. Clementine was equipped with an S-band microwave transponder and 2 S-band omni-directional high-rate antennas which were used for tracking by the NRL tracking station in Pomonkey, Maryland, and the NASA Deep Space Network. The frequency of the S-band transmission was measured every 10 sec., and the Doppler shift would give the relative velocity of the spacecraft towards or away from the Earth. Accelerations were calculated from changes in the velocity, and after accounting for the orbit, relative motions of Earth and Moon, and Earth and solar gravity, these accelerations are converted to lunar gravity effects on the spacecraft. The calculated lunar gravity field can be used to model subsurface lunar structure. The Pomonkey station could measure the velocity to an accuracy of 3 mm/s, while the Deep Space Network stations could acheive about 0.3 mm/s. Tracking was not possible on most of the lunar farside (120 to 240 long., -45 to 45 lat.), when the Moon was between the spacecraft and the Earth. In all, over 361,000 observations were made, approximately 57,000 at less than 1000 km altitude.

Alternate Names

  • Clementine Radio Science
  • Clementine/ClementineS-BandTransponderDopplerGravityExperiment

Facts in Brief

Mass: 8.27 kg
Bit rate (avg): 128 kbps

Funding Agencies

  • Department of Defense-Department of the Navy (United States)
  • NASA-Office of Space Science (United States)

Discipline

  • Planetary Science: Geology and Geophysics

Additional Information

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

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. Paul D. SpudisDeputy Team LeaderLunar and Planetary Institutespudis@lpi.usra.edu
Dr. Eugene M. ShoemakerTeam LeaderUS Geological Survey
Prof. Jacques E. BlamontTeam MemberCNRS, Service d'Aeronomie
Mr. Merton E. DaviesTeam MemberRand Corporation
Dr. David E. SmithTeam MemberNASA Goddard Space Flight Centerdavid.e.smith@nasa.gov
Dr. Daniel N. BakerTeam MemberUniversity of Coloradodaniel.baker@colorado.edu
Mr. Thomas C. DuxburyTeam MemberNASA Jet Propulsion Laboratorytduxbury@gmu.edu
Dr. Bonnie J. BurattiTeam MemberNASA Jet Propulsion Laboratorybburatti@scn1.jpl.nasa.gov
Dr. Carle M. PietersTeam MemberBrown Universitycarle_pieters@brown.edu
Mr. Charles H. ActonTeam MemberNASA Jet Propulsion Laboratorycacton@mail3.jpl.nasa.gov
Mr. Eric EliasonTeam MemberUS Geological Surveyeeliason@usgs.gov
Dr. Alfred S. McEwenTeam MemberUS Geological Surveymcewen@pirl.lpl.arizona.edu
Dr. Paul G. LuceyTeam MemberUniversity of Hawaiilucey@pgd.hawaii.edu

Selected References

  • Lemoine, F. G. R., et al., A 70th degree lunar gravity model (GLGM-2) from Clementine and other tracking data, J. Geophys. Res., 102, No. E7, 16339-16359, July 1997.

Other Clementine Information at NSSDCA

Clementine overview

Other Sources of Clementine Data/Information

Clementine Gravity and Topography Data

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