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| Risultati della ricerca nelle immagini - "Polar" |
00-PhoenixLiftoff.jpgThe beginning...76 visiteCaption NASA:"Can Mars sustain life? To help answer this question, last week NASA launched the Phoenix Mission to Mars. In May 2008, Phoenix is expected to land in an unexplored North Polar Region of Mars that is rich in water-ice. Although Phoenix cannot move, it can deploy its cameras, robotic arm, and a small chemistry laboratory to inspect, dig, and chemically analyze its landing area. One hope is that Phoenix will be able to discern telling clues to the history of ice and water on Mars. Phoenix is also poised to explore the boundary between ice and soil in hopes of finding clues of a habitable zone there that could support microbial life.
Phoenix has a planned lifetime of 3 months on the Martian surface".MareKromium
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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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000-Phoenix_Logo.jpgThe Phoenix Mars Lander Logo52 visiteThe Phoenix, a fabulous mythical bird the size of an eagle, symbolizes rebirth in many ancient cultures. According to the ancient Greeks, the bird lives in Arabia, nearby a cool well and sings a beautiful morning song. The Phoenix lives 500 years or longer with only one Phoenix existing at a time.
When the bird's death approaches, it bursts into flames, and a new bird springs from the consumed pyre.
Similar to its namesake, the Phoenix Mission "raises from the ashes" a spacecraft and instruments from 2 previous unsuccessful attempts to explore Mars: the Mars Polar Lander and the Mars Surveyor 2001 Lander. The Mars Polar Lander failed to return data upon its arrival to Mars' antarctic region on December 3, 1999 and left many ambitious science goals undone. Phoenix uses 3 instruments from this earlier Polar Lander, the SSI, the RA and the TEGA.
The Phoenix Mission uses the Mars Surveyor 2001 Lander, built in 2000, but later administratively mothballed. The '01 lander is undergoing modifications to improve the spacecraft's robustness and safety during entry, descent, and landing. Phoenix recovers two instruments delivered for the '01 lander that have been in protected storage: the MARDI and the MECA. Also, the RA has been modified from the '01 lander version.
MareKromium
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001-Kaguya-20071009_kaguya_02l.jpgRstar Separation from Kaguya (1) - before separation98 visiteKAGUYA consists of the Main Orbiter and two small satellites (Relay Satellite and VRAD Satellite). The Main Orbiter will reach the vicinity of the Moon. Once it has reached the Moon, it will be placed into a peripolar orbit at an altitude of 100 Km. The Relay Satellite will be placed in an elliptic orbit at an apogee of 2400 Km, and will relay communications between the Main Orbiter and the ground station.
The VRAD Satellite will play a significant role in measuring the gravitational field around the Moon.
The Main Orbiter will be employed for about one year and will observe the entire Moon.
(in this picture: on the left is the Rstar, and on the right is the VRAD Satellite).MareKromium
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001-Schiaparelli_e_osservazioni.jpgPlanet Mars, according to Schiaparelli53 visiteNei disegni del Grande Schiaparelli si nasconde, forse, un "Mistero" che nessuno si mai preso la briga di investigare a fondo.
Quale? In realt ce ne sarebbero parecchi, ma noi ne vorremmo evidenziare uno su tutti: la nitidezza e l'estremo livello di dettaglio delle mappe disegnate dall'Astronomo e quanto lui poteva - umanamente ed effettivamente - vedere usando lo strumento che aveva a disposizione.
In altre parole: c' TROPPO dettaglio e TROPPA precisione nei disegni di Schiaparelli rispetto a quanto egli potrebbe avere effettivamente osservato.
Ed a nulla valgano le obiezioni secondo cui il Grande Astronomo "approfitt al meglio" sia della vicinanza (che sempre relativa) del Pianeta Rosso alla Terra nella Grande Opposizione del 1877, e sia delle notevoli doti naturali proprie del suo strumento e dei suoi occhi.
La verit che neppure il Telescopio Spaziale Hubble riesce a vedere Marte con il dettaglio evidenziato dai disegni di Schiaparelli.
E allora?
E allora, delle due l'una: o Schiaparelli colm le (evidenti e naturali) lacune insite nelle sue osservazioni con un pizzico di fantasia, oppure egli vide (anche se il "come abbia fatto" non ci dato saperlo) il Pianeta Rosso come nessuno mai ha potuto e pu.
Tertium non datur.
da "Wikipedia":"...Molto popolari presso il grande pubblico furono le osservazioni al telescopio del pianeta Marte compendiate da Schiaparelli in tre pubblicazioni: "Il pianeta Marte" (1893), "La vita sul pianeta Marte" (1895) e "Il pianeta Marte" del 1909. Durante la grande opposizione del 1877, Schiaparelli osserv sulla superficie del pianeta una fitta rete di strutture lineari che chiam "canali". I canali di Marte divennero ben presto famosi, dando origine a una ridda di ipotesi, polemiche, speculazioni e folklore sulle possibilit che il pianeta rosso potesse ospitare forme di vita senzienti.
L'autore scriveva:
Piuttosto che veri canali della forma a noi pi familiare, dobbiamo immaginarci depressioni del suolo non molto profonde, estese in direzione rettilinea per migliaia di chilometri, sopra larghezza di 100, 200 chilometri od anche pi. Io ho gi fatto notare altra volta, che, mancando sopra Marte le piogge, questi canali probabilmente costituiscono il meccanismo principale con cui l'acqua (e con essa la vita organica) pu diffondersi sulla superficie asciutta del pianeta
(Giovanni Schiaparelli, La vita sul pianeta Marte, estratto dal fascicolo N. 11 - Anno IV della rivista Natura ed Arte, maggio 1895, cap. I)
La maggior parte delle speculazioni sull'esistenza di una civilt aliena su Marte fu favorita da un'errata traduzione in inglese del lavoro di Schiaparelli. La parola canali fu, infatti, tradotta con il termine canals invece del pi corretto channels. Mentre la prima parola indica una costruzione artificiale, il secondo termine definisce una conformazione del terreno che pu essere anche di origine naturale.
L'astronomo statunitense Percival Lowell fu uno dei pi ferventi sostenitori della natura artificiale dei canali marziani e condusse una dettagliata serie di osservazioni (compendiata nelle pubblicazioni: "Mars", 1895; "Mars and Its Canals", 1906; "Mars As the Abode of Life", 1908) a sostegno dell'ipotesi che i canali fossero delle imponenti opere di ingegneria idraulica progettate dai marziani per meglio gestire le scarse risorse idriche del pianeta.
Tra gli scienziati che contestarono l'esistenza dei canali, vi furono l'astronomo italiano Vincenzo Cerulli (tra i primi ad avanzare l'ipotesi che le strutture di Schiaparelli fossero illusioni ottiche come successivamente dimostrato), l'astronomo inglese Edward Walter Maunder (che condusse degli esperimenti visivi al fine di dimostrare la natura illusoria dei canali) e il naturalista inglese Alfred Russel Wallace che, nel libro "Is Mars Habitable?" (1907) critic aspramente le tesi di Lowell affermando che la temperatura e la pressione atmosferica del pianeta erano troppo basse perch potesse esistere acqua in forma liquida, e che tutte le analisi spettroscopiche effettuate fino a quel momento avevano escluso la presenza di vapore acqueo nell'atmosfera marziana.MareKromium
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007-Mars_South_Pole.jpgThe South Polar Region of Mars104 visitenessun commento
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01-SMART-1%20northpole29Dec4.jpgThe "North Pole" of the Moon132 visiteCaption ESA originale:"This image was taken by the AMIE camera on board SMART-1 on 29 December 2004 from a distance of 5.500 Km.
It shows an area, 275 Km across, of heavily cratered highland terrain close to the Lunar North Pole (upper left corner).
The image is used to monitor illumination of the polar areas, and long shadows cast by large crater rims".
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011-Mars_North_Pole.jpgThe North Polar Region of Mars136 visitenessun commento
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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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018-Mars_Magnetic_Anomalies.jpgThe Magnetic Anomalies of Mars54 visiteThe Magnetic Anomalies found by the MAG/ER experiment on the Mars Global Surveyor spacecraft are inconveniently bisected by the 180 Longitude line, and so appear at both ends of the standard Mars Mercator Projection.
Here, the MAG/ER team have made hemispheric projections centered on the area of strongest anomalies.
The 3 hemispheres show the 3 components of the Magnetic Field: B(r) is the Radial Field, which is perpendicular to Mars' Surface; B(Θ) is the Polar Field, oriented along lines of Longitude; and B(Φ) is the Circumferential Field, oriented along lines of Latitude. MareKromium
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021-Mars_Poles.jpgThe Poles of Mars52 visiteThe Mercator Projection distorts Polar Regions beyond recognition, so Polar Projection Maps are commonly made separately. These MOLA shaded topography images of Mars's North and South Polar Regions are stereographic projections, from Latitudes 72 N and S towards the respective Poles. The line of 0 Longitude is to the bottom of the North Pole images, and toward the top of the South Pole image.
Both Poles are covered by layered ice caps with smooth undulating surfaces. The North Polar Cap sits of a flat plain, while the South Polar Cap sits on heavily cratered land.MareKromium
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022-Mars_Water-1.jpgWhere is the "Water" of Mars? (Polar Regions)52 visiteWater abundances in the Martian Polar Regions, from the Neutron Spectrometer on Mars Odyssey, are shown here to complement the Mercator Projections of Equatorial Regions.
The North Pole is nearly pure water ice, while the South Pole is water iced mixed with other stuff, most likely dry ice (CO2) and mineral dust.
More details are available in the Los Alamos National Lab press release.MareKromium
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