NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header

Clementine

NSSDCA/COSPAR ID: 1994-004A

Description

Clementine was a joint project between the Ballistic Missile Defense Organization (BMDO, nee the Strategic Defense Initiative Organization, or SDIO) and NASA. The objective of the mission was to test sensors and spacecraft components under extended exposure to the space environment and to make scientific observations of the Moon and the near-Earth asteroid 1620 Geographos. The Geographos observations were not made due to a malfunction in the spacecraft. The lunar observations made included imaging at various wavelengths in the visible as well as in ultraviolet and infrared, laser ranging altimetry, gravimetry, and charged particle measurements. These observations were for the purposes of obtaining multi-spectral imaging the entire lunar surface, assessing the surface mineralogy of the Moon and obtaining altimetry from 60N to 60S latitude and gravity data for the near side. There were also plans to image and determine the size, shape, rotational characteristics, surface properties, and cratering statistics of Geographos. Clementine carried seven distinct experiments on-board: a UV/Visible Camera, a Near Infrared Camera, a Long Wavelength Infrared Camera, a High Resolution Camera, two Star Tracker Cameras, a Laser Altimeter, and a Charged Particle Telescope. The S-band transmitter was used for communications, tracking, and the gravimetry experiment.

Spacecraft and Subsystems

The spacecraft was an octagonal prism 1.88 m high and 1.14 m across with two solar panels protruding on opposite sides parallel to the axis of the prism. A high-gain fixed dish antenna was at one end of the prism, and the 489 N thruster at the other end. The sensor openings were all located together on one of the eight panels, 90 degrees from the solar panels, and protected in flight by a single sensor cover. The spacecraft propulsion system consisted of a nonpropellant hydrazine system for attitude control and a bipropellant nitrogen tetraoxide and monomethyl hydrazine system for the maneuvers in space. The bipropellant system had a total capability of about 1900 m/s with about 550 m/s required for lunar insertion and 540 m/s for lunar departure. Attitude control was achieved with 12 small attitude control jets, two star tracker cameras, and two inertial measurement units. The spacecraft was three-axis stabilized in lunar orbit via reaction wheels with a precision of 0.05 Deg. in control and 0.03 Deg. in knowledge. Power was provided by gimbaled, single axis, GaAs/Ge solar panels which charged a 15 amp-hour, 47 W-hr/kg Nihau (Ni-H) common pressure vessel battery. Spacecraft data processing was performed using a MIL-STD-1750A computer (1.7 million instructions per second) for savemode, attitude control, and housekeeping operations, a RISC 32-bit processor (18 million ips) for image processing and autonomous operations, and an image compression system provided by the French Space Agency CNES. A data handling unit sequenced the cameras, operated the image compression system, and directed the data flow. Data was stored in a 2 Gbit dynamic solid state data recorder.

Mission Profile

The mission had two phases. After two Earth flybys, lunar insertion was achieved approximately one month after launch. Lunar mapping took place over approximately two months, in two parts. The first part consisted of a five hour elliptical polar orbit with a periapsis of about 400 km at 30 degrees south latitude and an apoapsis of 8300 km. Each orbit consisted of an 80 minute lunar mapping phase near periapsis and 139 minutes of downlink at apoapsis. After one month of mapping the orbit was rotated to a periapsis at 30 degrees north latitude, where it remained for one more month. This allowed global imaging and altimetry coverage from 60 degrees south to 60 degrees north, over a total of 300 orbits. After a lunar/Earth transfer and two more Earth flybys, the spacecraft was to head for Geographos, arriving three months later for a flyby, with a nominal approach closer than 100 km. Unfortunately, on 07 May 1994, after the first Earth transfer orbit, a malfunction aboard the craft caused one of the attitude control thrusters to fire for 11 minutes, using up its fuel supply and causing Clementine to spin at 80 rpm. Under these conditions, the asteroid flyby could not yield useful results, so the spacecraft was put into a geocentric orbit passing through the Van Allen radiation belts to test the various components on board. The mission ended in June 1994 when the power level onboard dropped to a point where the telemetry from the spacecraft was no longer intelligible.

Further information and links to other resources are available at:

http://nssdc.gsfc.nasa.gov/planetary/clementine.html

Alternate Names

  • Deep Space Program Science Experiment
  • DSPSE
  • Clementine 1
  • 22973

Facts in Brief

Launch Date: 1994-01-25
Launch Vehicle: Titan II-G
Launch Site: Vandenberg AFB, United States
Mass: 227.0 kg
Nominal Power: 360.0 W

Funding Agencies

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

Disciplines

  • Planetary Science
  • Space Physics

Additional Information

Questions or comments about this spacecraft can be directed to: Dr. David R. Williams.

 

Personnel

NameRoleOriginal AffiliationE-mail
Lcol Pedro RustanMission ManagerUS Naval Research Laboratory 
Mr. Paul A. RegeonProject ManagerUS Naval Research Laboratoryregeon@ssdd.nrl.navy.mil
Dr. Lyn D. PleasanceProject ManagerLawrence Livermore Laboratorypleasance1@llnl.gov
Dr. Donald M. HoranProject ScientistUS Naval Research Laboratorydhoran@ssdd.nrl.navy.mil

Selected References

Nozette, S., et al., The Clementine mission to the Moon: Scientific overview, Science, 266, No. 5192, 1835-1839, Dec. 1994.

Sorensen, T. C., and P. D. Spudis, The Clementine mission -- A 10-year perspective, J. Earth Syst. Sci., 114, No. 6, 645-668, Dec. 2005.

Robinson, M., and M. Riner, Advances in lunar science from the Clementine mission: A decadal perspective, J. Earth Syst. Sci., 114, No. 6, 669-686, Dec. 2005.

Clementine

Moon Home Page
Moon Fact Sheet

Clementine Images of the Moon
Clementine Data at the PDS Imaging Node
Gravity and Topography Data at the PDS Geosciences Node

Clementine at the Naval Research Lab
Clementine at the Lunar and Planetary Science Institute

Detailed Clementine Information (PDS)
Lessons Learned from the Clementine Mission  (National Academy Press, 1997)

Clementine ISAS - Interstage Adapter Satellite

[USA.gov] NASA Logo - nasa.gov