Clementine 1 (DSPSE)

Launch data: Designation  22973 / 94004A Launch date  25 Jan 1994 - 16:34 UT Launch site  Va, SLC-4W Launch vehicle  Titan-2(23)G (#23G-11) Mission  Lunar-Orbiter, Asteroid-Flyby Operator   Heliocentric orbit Perihelion / Aphelion  804 x 409890 Incl. to ecliptic  63.8 ° Period   min

Clementine - Credit: USAF

Spacecraft data: Prime contractor  Naval Research Laboratory, Lawrence Livermore Nati Customer  BMDO, NASA Platform   Mass at launch  424 kg Dry Mass   kg Basic shape  octagonal prism Dimension  high: 1.88 m. Max. dia: 1.14 m Solar array  2 solar panels Stabilization  3-axis DC power  36 W Design lifetime  7 months

Description:

• Clementine was jointly sponsored by BMDO and NASA as the Deep Space Program Science Experiment (DSPSE). The principal objective was to space qualify lightweight imaging sensors and component technologies for the next generation of DOD spacecraft. Intended targets for these sensors included the Moon, a near-Earth asteroid (1620 Geographos), and the spacecraft's interstage adapter. After entering lunar orbit, Clementine providing over 1.6 million images of the Moon's surface. After the lunar mapping phase was completed, the spacecraft left lunar orbit for a planned encounter with Geographos, but was unable to rendezvous due to a spacecraft anomaly. Spacecraft: 3-axis stabilised. Dual GaAs solar arrays with 1-axis articulation. Fixed 1.1 m HGA. S-Band downlink to NASA DSN and DOD tracking stations with downlink rate up to 128 kbps.1.9 Gbit solid state recorder. Bipropellant system with 489 N thruster. Hydrazine system with 10 x 5.3 N and 7 x 22 N thrusters.32-bit R3000 processor. Lightweight RLG and IFOG (1 deg/hr). NiH2 CPV battery (15 AHr). Lightweight reaction wheels and star tracker cameras. JPEG image compression chip (from Matra Marconi). Payload: Two miniature star tracker cameras. UV/Visible camera. Near-IR camera. Long wave IR camera. High resolution camera. Laser transmitter. Charged particle telescope. Dosimeters (4). Radiation experiment. Orbital meteoroid and debris counting experiment. Total payload is 8 kg and 68 watts.
• 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 details:

• First solar orbit launch from Vandenberg launch site.
• ISA (22987 / 94004C)
• SDIO sensor technology demonstration; mapped lunar surface; planned asteroid flyby cancelled due to spacecraft failure. Clementine was a joint project between the Strategic Defense Initiative Organization 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 observations included imaging at various wavelengths including ultraviolet and infrared, laser ranging altimetry, and charged particle measurements. These observations were originally for the purposes of assessing the surface mineralogy of the Moon and Geographos, obtaining lunar altimetry from 60N to 60S latitude, and determining the size, shape, rotational characteristics, surface properties, and cratering statistics of Geographos.
• The Clementine 1 (formally Deep Space Program Sensor Experiment or DSPSE) probe was launched into a 255 x 299 x 67.0 deg Earth orbit on Jan 25, 1994. The attached Star 37 kick motor was due to fire in early February to send it on a trip to the Moon; if the burn is successful, it will be the first lunar or planetary probe to be launched from the Vandenberg AFB site in California. The launch vehicle was a recycled Titan II ICBM, and the spacecraft was built by the Naval Research Lab for the Ballistic Missile Defense Organization (BMDO, formerly SDIO - "Star Wars"). The idea is to test infrared and ultraviolet sensors after exposing them to the space environment. Clementine is scheduled to map the Moon and then go on to fly past minor planet (1620) Geographos.
• The Clementine space probe is on its way to the Moon. The Star 37 apogee motor fired on Feb 3 at 06:28 UTC, placing the probe in a 168 x 128095 km orbit inclined 66.8 deg to the Earth's equator.
• After two Earth flybys, the Clementine probe entered lunar orbit on Feb 21, 1994. The lunar orbit insertion burn happened at 12:51 UTC on Feb 19 and lasted for 6 minutes; a day later, at 12:42 UTC on Feb 20 a second burn was used to reach the operational orbit.
  It is reportedly in a 401 x 2952 km orbit with an inclination of 89.7 deg to the lunar equator.
  
• Lunar mapping took place over approximately two months, in two parts. The first part consisted of a 5 hour elliptical polar orbit with a perilune of about 400 km at 28 degrees S latitude. After one month of mapping the orbit was rotated to a perilune of 29 degrees N latitude, where it remained for one more month. This allowed global imaging as well as altimetry coverage from 60 degrees S to 60 degrees N.
• Clementine 1 made orbit trim burns on Mar 25 and Mar 26, 1994 to change the latitude of its perilune from 30 deg S to 30 deg N, improving mapping coverage of the northern hemisphere. Clementine will depart lunar orbit in May.
• Clementine left lunar orbit on May 4, 1994 at 0324:15 UTC. Perigee was due on May 8 at 0556, and apogee will be at 0530 on May 16, when a targeting maneuver will be performed. Second perigee will be around May 24, and Clementine will fly past the moon again on May 27 on its way to solar orbit. It will reach asteroid (1620) Geographos at 2116 UTC on Aug 31.
• Unfortunately, on May 07, 1994 at 14:39 UTC (9:39 AM EST) 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.
• This made the planned continuation of the mission, a flyby of the near-Earth asteroid Geographos, impossible. The spacecraft remained in geocentric orbit and continued testing the spacecraft components until the end of mission.
• 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.