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000-Clementine.gif000 - Clementine55 visiteDescription
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 7 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 meters 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 May 7, 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.
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0009-Artemis_One-Far_Side_of_the_Moon.jpgThe bright and yet dark side of the Moon...82 visiteNASA officials say Artemis 1 mission teams are "giddy" after witnessing how well their Orion spacecraft has been performing so far on its way towards Lunar Orbit.
Artemis 1 launched at 01:47 EST (06:47 GMT) on Nov. 16, blasting off from Kennedy Space Center in Florida in a spectacular display of the sheer power of NASA's Space Launch System (SLS) rocket. The Orion spacecraft reached Earth orbit shortly after, and then at 87 minutes after launch performed a so-called Trans Lunar Injection burn to send it hurtling towards the moon. On Monday (Nov. 21), Orion performed another burn to send the Spacecraft close enough to the Lunar Surface to leverage (---> use, take advantage of) the Moon's Gravity to pull the Spacecraft around the Moon itself into a distant retrograde orbit.
After collecting data from that propulsive maneuver, NASA Officials held a briefing Monday evening (Nov. 21) to discuss Orion's powered flyby of the Moon. Judd Frieling, flight director at NASA's Johnson Space Center, said Orion Mission Team Members are "giddy" (to have a sensation of whirling and then a tendency to fall; synonym: dizzy) with the current performance they are seeing from the spacecraft after the flyby, which saw the Spacecraft come within about 80 miles of the Lunar Surface.MareKromium
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015-The Moon from Clem-FarSide-PIA00304.jpg002 - The Far-Side of the Moon54 visiteClementine Project Information
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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.
Clementine was launched on 25 January 1994 at 16:34 UTC (12:34 PM EDT) from Vandenberg AFB aboard a Titan IIG rocket. After two Earth flybys, lunar insertion was achieved on February 21. 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.
After leaving lunar orbit, a malfunction in one of the on-board computers on May 7 at 14:39 UTC (9:39 AM EST) caused a thruster to fire until it had used up all of its fuel, leaving the spacecraft spinning at about 80 RPM with no spin control. 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.
More information on the Clementine mission, instruments, and early results can also be found in the Clementine special issue of Science magazine, Vol. 266, No. 5192, December 1994.
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06-C_Mars04_Panorama1.jpgMars panorama from Mars-4 (1)95 visiteThe first in an armada of four spacecrafts launched in 1973, Mars-4 failed to enter orbit. During its flyby - on February 10, 1974 -, it returned 12 photographs from the 52mm "Vega" phototelevision camera, all through the red filter. It also returned 2 panoramas from the optical-mechanical cameras. Image data was returned digitally by pulse position modulation.
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19981223.jpgViews of 433-Eros53 visiteThis montage of images of the asteroid Eros was assembled from images acquired by the Near Earth Asteroid Rendezvous (NEAR) Spacecraft on December 23, 1998, as the Spacecraft flew by the asteroid at a distance of 2300 miles (3800 Km) at 1:43 PM EST. Shown are nine early views out of 29 that were obtained during the flyby. These images were taken between 10:44 AM and 12:44 PM EST, as the Spacecraft range closed from 7300 miles (such as abou 11.100) Km, to 3300 miles (such as approx. 5300 Km).
During that time, the Asteroid completed nearly half of a rotation. The smallest resolved detail is approximately 1650 feet (500 meters) across.
A firing of the main engine at 17:00, EST, on December 20, 1998, designed to slow the Spacecraft for insertion into orbit around the Asteroid, was aborted by the Spacecraft. Contact with ground controllers was temporarily lost, but was regained at 20:00 EST on December 21, when autonomous Spacecraft safety protocols took over and transmitted a signal to the ground. All spacecraft systems were determined to be healthy and operational.
Within hours, a flyby observation sequence was developed and uploaded to the Spacecraft.
1026 images were acquired by the Multispectral Imager, to determine the size, shape, morphology, rotational state, and color properties of Eros, and to search for small moons.
The Infrared Spectrometer measured spectral properties of the Asteroid to determine what minerals were present, and the Magnetometer searched for a natural Magnetic Field.
Analysis of the Spacecraft radio signal were also used to determine the asteroid's mass and density.
The main engine was fired successfully on January 3, 1999, placing NEAR on-course for a February 2000 rendezvous.
Eros is NEAR's second asteroid encountered. On June 27, 1997, NEAR flew by the Main-Belt Asteroid Mathilde at a range of approx. 1212 Km (750 miles).MareKromium
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52-The Shard-03-ZOND-3.jpgThe famous "Shard", on the Moon (4)101 visiteUn interessante frammento originale (integrato da qualche annotazione, pił o meno condivisibile, della Scuola del Prof. Hoagland) di un giornale del 1965 che riportava alcune immagini "lanciate" a Terra dalla Sonda Sovietica ZOND-3.
"...Zond 3 was launched from a Tyazheliy Sputnik Earth orbiting platform towards the Moon and Interplanetary Space.
The spacecraft was equipped with an f106 mm camera and TV system that provided automatic inflight film processing. On July 20/'65 lunar flyby occurred approx. 33 hours after launch at a closest approach of 9200 Km 25 pictures of very good quality were taken of the Lunar Far-Side from distances of 11.570 to 9.960 Km over a period of 68 minutes.
The photos covered about 19.000.000 square/km of the lunar surface. Photo transmissions by facsimile were returned to Earth from a distance of about 2,2 MKM and were retransmitted from a distance of 31,5 MKM (some signals still being transmitted from the distance of the orbit of Mars), thus proving the ability of the communications system. After the lunar flyby, Zond 3 continued space exploration in a heliocentric orbit..."
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Amalthea-Galileo.jpgAmalthea, from Galileo53 visiteOn its way in and out, Galileo took these two snapshots of Amalthea. The purpose was to improve navigation for the upcoming flyby of this little moonlet, but such images also help in the study of the shape of irregular worlds.MareKromium
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Amalthea-PIA07248_modest.jpgAmalthea: just an "Ice Cube"!55 visiteThese images of Jupiter's moon Amalthea were taken with NASA's Galileo and Voyager spacecraft. Recent findings show that Amalthea is almost pure water ice, hinting that it may not have formed where it now orbits! This information challenges long-held theories about how moons form around giant planets. The image on the left shows the Escape Velocities (EV) color-coded on a shape model of Amalthea with the same viewpoint as the Voyager spacecraft image in the middle panel. Blue represents the lowest EV, barely 1 mt/second (about 3 feet) near the anti-Jupiter end, while red (barely visible) shows the region of much higher EV, nearly 90 mt/second (295 feet). The low EV result from the low density of Amalthea and from its rapid rotation as it orbits Jupiter.
The middle image is a composite from both Galileo and NASA's Voyager spacecraft and shows Amalthea from the anti-Jupiter side. The visible area is about 150 Km (about 93 miles) across.
The Sun is behind the spacecraft, resulting in loss of visible shadows. The brighter markings on the ends of a ridge are prominent in this view.
On the right is a Galileo image of Amalthea, (see PIA02532), with the bright spots on the end of Amalthea seen from the leading side of the satellite. Here the Sun is to the left and topography, such as the impact crater at the right, is visible.
Amalthea is Jupiter's fifth largest moon. It orbits about 181,000 kilometers (112,468 miles) from Jupiter, considerably closer than the Moon orbits Earth. It measures about 168 miles in length and half that in width. Galileo passed within about 99 miles of the moon on Nov. 5, 2002. After more than 30 close encounters with Jupiter's four largest moons, the Amalthea flyby was the last moon flyby for Galileo. The mission began orbiting the planet in 1995.
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Asteroids-Annefrank_Asteroid-PIA02885_modest.jpgAsteroid Annefrank from Stardust62 visiteAsteroid Annefrank is seen as irregularly shaped, cratered body in an image taken by NASA's Stardust spacecraft during a Nov. 2 flyby of the asteroid.
Stardust flew within about 3.300 Km (about 2.050 miles) of the asteroid as a rehearsal for the spacecraft's encounter with its primary target, comet Wild 2, in January 2004. The camera's resolution was sufficient to show that Annefrank is about 8 Km (5 miles) in length, twice the predicted size from Earth-based observations. The surface reflects about 0,1 to 0,2% of sunlight, slightly less than anticipated. A few craters that are hundreds of meters across can be seen. The straight edge in the right side of the image may be an artifact of processing.
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Asteroids-Asteroid_1994-CC-PIA12134.gifTriple Asteroid 1994-CC in motion (GIF-Movie; credits: NASA/JPL/GSSR)53 visiteCaption NASA:"Radar imaging at NASA's Goldstone Solar System Radar on June 12 and 14, 2009, revealed that near-Earth Asteroid 1994-CC is a Triple System.
Asteroid 1994 CC encountered Earth within 2,52 MKM (such as 1,56 MMs) on June 10. Prior to the flyby, very little was known about this celestial body. 1994 CC is only the second Triple System known in the near-Earth population. A team led by Marina Brozovic and Lance Benner, both scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif., made the discovery.
1994-CC consists of a central object about 700 meters (2300 feet) in diameter that has two smaller moons revolving around it. Preliminary analysis suggests that the two small satellites are at least 50 meters (164 feet) in diameter.
Radar observations at Arecibo Observatory in Puerto Rico, led by the center's director Mike Nolan, also detected all 3 objects, and the combined observations from Goldstone and Arecibo will be utilized by JPL scientists and their colleagues to study 1994-CC's orbital and physical properties.
The next comparable Earth flyby for Asteroid 1994-CC will occur in the year 2074 when the space rock trio flies past Earth at a distance of about 2,5 MKM (such as approx. 1,6 million miles). Of the hundreds of near-Earth asteroids observed by radar, only about 1% are Triple Systems".MareKromium
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Comets-Wild_2-00.jpgApproaching Wild 2 (1)54 visiteCaption NASA originale:"This image was taken during the close approach phase of Stardust's Jan 2, 2004 flyby of comet Wild 2. It is a distant side view of the roughly spherical comet nucleus. One hemisphere is in sunlight and the other is in shadow analogous to a view of the quarter moon. Several large depressed regions can be seen. Comet Wild 2 is about 5 Km (3,1 miles) in diameter".
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Comets-Wild_2-01.jpgApproaching Wild 2 (2)57 visiteCaption NASA originale:"On January 2, 2004 NASA's Stardust spacecraft made a close flyby of comet Wild 2.
Among the equipment the spacecraft carried on board was a navigation camera.
This is the 34th of the 72 images taken by Stardust's navigation camera during close encounter. The exposure time was just 10 milliseconds".
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