153 lines
8.0 KiB
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153 lines
8.0 KiB
Plaintext
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SUBJECT: CLEMENTINE MISSION TO MAP MOON FILE: UFO2395
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From the "JPL Universe"
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February 25, 1994
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LAB PLAYING KEY ROLE IN CLEMENTINE MISSION TO MAP MOON, FLY BY ASTEROID
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By Mark Whalen
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JPL is playing an important role in a joint
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military-scientific mission that will space-qualify lightweight
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sensors and component technologies for the next generation of
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Defense Department spacecraft, map the Moon, and conclude with a
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close encounter with a near-Earth asteroid.
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The Clementine mission, sponsored by the Ballistic Missile
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Defense Organization (BMDO) (formerly known as the Strategic
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Defense Initiative Organization) was launched Jan. 25 from
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Vandenberg Air Force Base on a Titan II-G rocket; the
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231-kilogram (508-pound) spacecraft went into a polar lunar orbit
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Feb. 19. Systematic lunar mapping is scheduled to begin about a
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week later and continue through early May, followed by the first
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flyby of the near-Earth asteroid 1620 Geographos. The $75-million
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mission took only 22 months from conception to launch.
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Designed and built by the Naval Research Laboratory (NRL),
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the spacecraft was originally conceived to test advanced,
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lightweight technologies for ballistic-missile defense
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applications. Lawrence Livermore National Laboratory of
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California built most of the scientific payload. NASA became
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involved when scientists arranged to participate in the mission
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to create unprecedented maps of the moon in addition to the
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asteroid encounter.
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The Lab is supporting the mission on four fronts, with teams
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overseeing a radiation and reliability experiment for advanced
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microelectronic devices; dynamical, photometric and cartographic
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studies; Deep Space Network (DSN) tracking and navigation; and
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engineering studies of the Clementine systems' performance and
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Clementine's daughter satellite, the Interstage Adapter Satellite
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(ISAS).
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Dr. Satish Khanna of the Center for Space Microelectronics
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Technology Division 820 is program manager for RRELAX (the
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Radiation and Reliability Assurance Experiment), which will
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characterize the radiation resistance and reliability of three
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advanced microelectronic devices: charged-couple devices,
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complementary metal oxide silicon and static random-access
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memory. The experiment, whose principal investigator is Dr.
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Martin Buehler of Section 346, comprises two hardware boxes, one
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on the spacecraft and one on the ISAS.
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Khanna said that "within nine months, we designed,
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fabricated, tested and delivered the two RRELAX boxes to NRL for
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integration into the spacecraft and ISAS.
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"This experience will be useful for JPL's plan to
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participate in cheaper, faster and better missions," he added.
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Tom Duxbury of the Geology and Planetology Section 326 is
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one of the three JPL members of the NASA-sponsored science team.
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"We will obtain high-resolution coverage of the moon," he said,
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"with precision radio science yielding the gravity field, a laser
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altimeter giving topography, and stereo imaging giving a global
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cartographic control network--the first time we have had those
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simultaneously."
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The total amount of data transmitted from the moon mapping
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will be comparable to that obtained during the first Magellan
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mapping cycle of Venus. "It's global coverage, not just bits and
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pieces or strips (of the moon)," Duxbury added. Earlier missions
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to the moon, including Apollo, mainly orbited the equatorial
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regions.
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Clementine is scheduled to reach Geographos on Aug. 31,
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after which time more than 2,000 images will be recorded and
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stored on board in the solid-state memory for later playback to
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Earth. Duxbury said the cigar-shaped asteroid measures about 1
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1/2 km by 4 km (9/10 mile by 2 1/2 miles), and its orbit is
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inclined about 16 degrees to Earth's ecliptic plane. The
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spacecraft will pass within 100 km (62 miles) of Geographos, when
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it will be 8 million km (5 million miles) from Earth.
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Clementine's cameras will be programmed to autonomously
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track the asteroid while passing from the dark to the sunlit side
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at close range; as the spacecraft goes by, most of the
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illuminated side will come into view. (A three-member optical
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navigation team from JPL's Section 314 will support this part of
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the mission.) Close-range images, when combined with Light
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Detection and Ranging (LIDAR) measurements, will enable an
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accurate determination of the asteroid's shape and size.
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JPL tracking stations at Goldstone, Calif.; Madrid, Spain;
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and Canberra, Australia--in conjunction with an NRL station in
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Pomonkey, Md., and a number of Air Force stations--will support
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the Clementine mission, according to Ray Amorose, manager of the
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TDA Mission Support and DSN Operations Division 440.
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"In general," he said, "we are using our 26-meter subnet,
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with some 34-meter support; in late May, it will be all 34-meter
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coverage because the spacecraft will be out of range of the
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26-meter antennas. When the spacecraft gets to the asteroid,
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there will be a couple of days of 70-meter coverage.
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"We're doing navigation and orbit-determination work,"
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Amorose added. "Goddard Space Flight Center in Maryland is
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assisting NRL in orbit-determination and dynamics work on the
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early part of the mission; when it leaves the moon, then JPL
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becomes a major player for the navigation."
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About 30 JPL staff members are working on the mission.
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Amorose noted that a particularly special effort has been made in
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recent weeks by Al Berman of Division 440, the project's tracking
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and data system manager, whose Granada Hills home was severely
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damaged by the Jan. 17 Northridge earthquake. "He came in anyway
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and did his job," Amorose said. "He is a pretty dedicated guy."
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In addition to the on-Lab support, Dr. Henry Garrett of
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Division 52 is currently on detail to the Clementine program
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office. Garrett heads the Clementine engineering team, which is
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evaluating the overall performance of the advanced technologies
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being tested on the vehicle. He is also program manager for ISAS,
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which was left behind by the main Clementine spacecraft following
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the first lunar transfer orbit injection.
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The ISAS carries a copy of the RRELAX experiment, a dust
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detector provided by NASA's Langley Research Center, and several
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microelectronics experiments provided by NRL. The NRL-designed
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package cost less than $1 million and is intended to serve as a
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test of Clementine's microelectronics in the Earth's radiation
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environment, Garrett said. JPL is currently receiving data on the
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radiation environment and on the performance of the RRELAX test
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devices from both the ISAS and Clementine.
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The Clementine mission is the first non-NASA deep-space
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mission conducted by the United States. "As far as the NASA
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science community is concerned, it's a high-payoff mission,"
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Duxbury said. "For the Defense Department, it's testing specific
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technology it needs to do its business."
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According to a BMDO statement, "The use of celestial bodies
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such as the moon and a near-Earth asteroid makes ideal targets to
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flight-qualify advanced lightweight technologies developed by
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BMDO. The added cost of the mission by going to deep space is
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actually less than the cost of developing and deploying the
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targets that would be required to test the payload in low-Earth
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orbit.
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"By performing a joint mission with NASA and forming a
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NASA-selected science team to enhance the scientific value of the
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mission, it will also be possible to transfer these technologies
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for future space exploration."
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###
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___ _____ ___
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/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
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| | | | __ \ /| | | | Jet Propulsion Lab |
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___| | | | |__) |/ | | |__ Galileo S-Band | A mind stretched by a new
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/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | idea can never go back to
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|_____|/ |_|/ |_____|/ | its original dimensions.
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**********************************************
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* THE U.F.O. BBS - http://www.ufobbs.com/ufo *
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**********************************************
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