The Clementine SpacecraftClementine was the first of a new class of small spacecraft to enable long-duration deep space missions at low cost using lightweight satellite technology. Along with its primary mission to test this new technology, it returned valuable lunar data to the scientific community. Clementine was launched on January 25, 1994, from Vandenburg Air Force Base onboard a Titan IIG rocket. After two Earth flybys, lunar orbit was achieved on February 19, 1994. Lunar mapping took place over approximately two months in two systematic mapping passes over the Moon.
MISSION SUMMARY
Over the course of 71 days in orbit, Clementine systematically mapped the 38 million square kilometers of the Moon at eleven different wavelengths, from the ultraviolet (415 nm) to the near-infrared (2800 nm) parts of the spectrum (nearly 1,000,000 images). In addition, the spacecraft took 620,000 high-resolution and about 320,000 mid-infrared thermal images, mapped the topography of the Moon with laser ranging equipment, improved knowledge of the surface gravity of the Moon through radio tracking, and carried a charged-particle telescope to characterize the solar and magnetospheric energetic-particle environment.
After successfully completing the lunar mapping phase of the mission, Clementine suffered an onboard malfunction that resulted in the activation of its altitude thrusters. This exhausted all the fuel for altitude control and left the spacecraft spinning at 80 revolutions per minute. This prevented Clementine from performing the planned close flyby on the near-Earth asteroid Geographos. Observations of the Moon were organized into four periods as follows.
First Observational Period
Orbits 1-31 were the shakedown and testing period, during which the spacecraft observation sequences were tested and refined. Observations of special targets, such as Apollo landing sites, were acquired during this period.Second Observational Period
Orbit 32-168 were the first month's systematic mapping passes. This period started on February 26 and ended on March 26, 1994.Third Observational Period
Orbits 169-297 were the second month's systematic mapping passes. This period started on March 26 and ended on April 21, 1994.Fourth Observational Period
Orbits 298-348 were used to make observations to fill in gaps in the coverage, acquire observations of special targets, acquire stereo observations over Orientale Basin, and obtain calibration data.
CURRENT LPI RESEARCH USING CLEMENTINE DATA
Scientists at the LPI are using data acquired by Clementine to answer important questions about the Moon. These questions include the global three-dimensional composition of the lunar crust, the possibility of ice at the south pole, the composition of mare basalts on the Moon's farside, and the chemical heterogeneity of the Apollo 16 landing site. The answers to these questions will allow scientists to better understand the formation of primary and secondary crusts on the Moon, increase knowledge of the geology at the Apollo landing sites, and yield information that will influence planning of future return missions to the Moon.
CLEMENTINE INSTRUMENTS
Clementine carried four cameras, including one with a laser ranging system. The spacecraft also had two star tracker cameras, used mainly for altitude determination but also as wide-field cameras for various scientific and operational purposes. All sensors on the spacecraft met or exceeded expectations in their performance.
Clementine's imaging cameras are similar to LANDSAT multispectral data for Earth. Both measure reflected solar radiation, and both acquire data through several different bandpasses (filters). Each bandpass was carefully selected to cover parts of the spectrum for which surface materials exhibit known variations. In the case of Clementine, filters were assigned to observe areas in the visible and near-infrared spectrum that are sensitive to variations in bulk mineralogy (principally the abundance of iron-bearing silicates) and the cumulative amount of soil maturity.
Star Tracker Camera
The Star Tracker provides an inertial reference for the spacecraft by comparison of star field images with an onboard star map. Two of these cameras were flown on the Clementine Mission. [Instrument Details at NSSDC]
Ultraviolet/Visible Camera
This medium resolution camera uses CCD technology and operates in the near- ultraviolet and visible region of the spectrum. Combined with a six-position spectral filter wheel, this sensor was designed for mineralogical studies of the Moon. [Instrument Details at NSSDC]
Near Infrared Camera
This camera provided images in the 1-3 micrometer wavelength region at medium resolution. Combined with a six-position spectral filter wheel, this camera was used for mineralogical studies. [Instrument Details at NSSDC]
High Resolution Camera
This camera operated at visible wavelengths with CCD technology combined with an image intensifier and a six-position spectral filter wheel. It provided higher-resolution images free from spacecraft motion blur. [Instrument Details at NSSDC]
LIDAR System
This system was used to obtain altitude measurements during mapping orbits around the Moon. [Instrument Details at NSSDC]
Long Wave Infrared Camera
This lightweight camera operated in the thermal infrared region of the spectrum. It was used to measure the thermal emission from the Moon. [Instrument Details at NSSDC]
MORE CLEMENTINE INFORMATION AT THE LPI
MORE CLEMENTINE INFORMATION AT OTHER SITES
Clementine lunar image browser developed by Applied Coherent Technology (ACT)
Clementine Mission Information at Centre National D'Etudes Spatiales (CNES France)
Clementine Mission Information at Goddard Space Flight Center
Clementine Mission Information at Lawrence Livermore National Laboratory
Clementine Mission Information Navigator at Planetary Data System
Clementine Mission Information at National Space Science Data Center
Clementine Mission Information at Naval Research Laboratory
Clementine Mission Information at United States Geologic Survey