NSSDCA ID: 1994-004A-08
Mission Name: ClementineThe 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.
Mass: 8.27 kg
Bit rate (avg): 128 kbps
Questions and comments about this experiment can be directed to: Dr. David R. Williams
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. Paul D. Spudis | Deputy Team Leader | Lunar and Planetary Institute | spudis@lpi.usra.edu |
Dr. Eugene M. Shoemaker | Team Leader | US Geological Survey | |
Prof. Jacques E. Blamont | Team Member | CNRS, Service d'Aeronomie | |
Mr. Merton E. Davies | Team Member | Rand Corporation | |
Dr. David E. Smith | Team Member | NASA Goddard Space Flight Center | david.e.smith@nasa.gov |
Dr. Daniel N. Baker | Team Member | University of Colorado | daniel.baker@colorado.edu |
Mr. Thomas C. Duxbury | Team Member | NASA Jet Propulsion Laboratory | tduxbury@gmu.edu |
Dr. Bonnie J. Buratti | Team Member | NASA Jet Propulsion Laboratory | bburatti@scn1.jpl.nasa.gov |
Dr. Carle M. Pieters | Team Member | Brown University | carle_pieters@brown.edu |
Mr. Charles H. Acton | Team Member | NASA Jet Propulsion Laboratory | cacton@mail3.jpl.nasa.gov |
Mr. Eric Eliason | Team Member | US Geological Survey | eeliason@usgs.gov |
Dr. Alfred S. McEwen | Team Member | US Geological Survey | mcewen@pirl.lpl.arizona.edu |
Dr. Paul G. Lucey | Team Member | University of Hawaii | lucey@pgd.hawaii.edu |