| Ultimi arrivi - Mars through the eyes of Soujourner-Pathfinder |
SOU-SOL001-80817_full.jpgColor Panorama: Sol 1134 visiteOriginal caption:"This picture from Mars Pathfinder was taken at 9:30 AM in the martian morning or MLT (such as 14:30 PDT --> Pacific Daylight Time), after the Spacecraft landed on July 4, 1997. The picture shows the Sojourner Rover perched on 1 of 3 solar panels. The (mini)Rover is 65 cm (about 26") long by 18 cm (7") tall; each of its wheels is about 13 cm (5") high. The white material to the left of the front of the Rover is part of the airbag system used to cushion the landing.
Many rocks of different of different sizes can be seen in a background of reddish soil. The landing site is in the mouth of an ancient channel carved by water. The rocks may be primarily flood debris. The horizon is seen towards the top of the picture. The light brown hue of the sky results from suspended dust".Ago 13, 2005
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SOU-SOL001-80815_full.jpgColor Panorama: Sol 1129 visitePathfinder enters the upper atmosphere of Mars at 10:02 PDT and at a velocity of approx. 26.500 Km/hour and begins the sequence of events that will land the Spacecraft on the surface. From this point on, the only likely signal from the Spacecraft will be the carrier wave, a single frequency radio wave. The shifting frequency of the carrier, know as the "Doppler shift", will provide an indication of the decelerations occurring during entry and parachute deployment. The Spacecraft is also designed to send back a frequency-keyed signal following certain key events (this signal is called a "semaphore"). The semaphore is very weak and is not expected to be received in real time. However, careful analysis after-the-fact of the broad frequency spectrum recording of the radio signal will give the Operations Team considerable information on how events unfolded during the rapid descent to the surface.
Entry, descent and landing (EDL) takes approximately 4,5' and follows the sequence below:
Spacecraft rapidly decelerates in the atmosphere using the heatshield
Parachute deploys
Heat shield separates
Lander releases from backshell, descends on bridle
Radar altimeter returns information on altitude
Airbags inflate
Rocket-assisted deceleration (RAD) engines fire
Bridle cable is cut
Ago 13, 2005
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SOU-SOL001-80808_full.jpgColor Panorama: Sol 1234 visiteUn nuovo "album" per una "vecchia" Missione: il mini-rover Soujourner, la Sonda Patrhfinder (lett.: cerca-percorso) e le loro "visioni", ora a colori (spesso brutti) ed ora in b/n (decisamente molto meglio), di Marte.
Era il 4 Luglio (ma guarda che combinazione...) 1997 quando le prime immagini del Pianeta Rosso (Ares Vallis) incominciarono ad arrivare e si trattò di frames storici poichè, come la NASA stessa ci rammenta "...these images represent Humankind's return to the Red Planet. More than 20 years after the Viking I and II Missions, Pathfinder has landed on Mars!").
Nota: le immagini da guardare e commentare coprono solo 95 Soles: 30 relativi alla "Prime Mission" - e cioè sino al 3 Agosto 1997 - ed il resto per la "Extended mission" - vale a dire sino al 9 Ottobre 1997).
Una Missione breve? Forse si e forse no.
Una Missione interessante? Giudicatelo Voi!...Ago 13, 2005
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SOU-SOL001-1-Pathfinder-LandingSite-Viking1-01.jpgThe Pathfinder Landing Site, from Viking 1 (2)118 visiteMosaic of Viking Orbiter images illustrating the location of the Pathfinder Lander (approx. 19,17° North Lat. and 33,21° West Long in the USGS ref. frame) with respect to surface features. Prominent features on the horizon include North Knob, Southeast Knob, Far Knob, Twin Peaks and Big Crater. Two small craters visible in the Orbiter and Lander views (Little Crater and Rimshot Crater) lie on the NW outer flank of the rim of Big Crater. Since the Lander is on the SE-facing flank of a low ridge, very distant features to the South and East are in view, whereas relatively nearby features to the North are partially or completely obscured. Only the tip of North Knob, which appears larger in the Viking orbiter images than the Twin Peaks, projects above the Local Horizon, and a 300-m crater, 1.2 km to the North/East, is completely obscured".Mag 19, 2005
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SOU-SOL008-PIA01004.jpgDeflated Airbags and Skyline - Soles 8, 9 and 10 (Natural Colors; credits: NASA/JPL)129 visiteCaption NASA originale:"This is a sub-section of the geometrically improved and color enhanced version of the 360° panorama known as the "Gallery Pan", the first contiguous, uniform panorama taken by the Imager for Mars Pathfinder (IMP) over the course of Soles 8, 9 and 10. Different regions were imaged at different times over the 3 Martian days to acquire consistent lighting and shadow conditions for all areas of the panorama.
The IMP is a stereo imaging system that, in its fully deployed configuration, stands 1,8 mt above the Martian surface and has a resolution of 2 mm at a range of 2 mt. In this geometrically improved version of the panorama, distortion due to a 2,5° tilt in the IMP camera mast has been removed, effectively flattening the horizon. The IMP has color capability provided by 24 selectable filters -- twelve filters per "eye". Its red, green, and blue filters were used to take this image. The color was digitally balanced according to the color transmittance capability of a high-resolution TV at the Jet Propulsion Laboratory (JPL), and is dependent on that device. In this color enhanced version of the panorama, detail in surface features are brought out via changes to saturation and intensity, holding the original hue constant. A threshold was applied to avoid changes to the sky".Gen 25, 2005
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SOU-SOL033-PIA01006.jpgThe "Meteorology Mast" - MET - Sol 33 (Enhanced Natural Colors; credits: NASA/JPL)93 visiteCaption NASA originale:"The Mars Pathfinder Meteorology Mast casts a shadow on the Lander Solar Array, as seen in this superpan mosaic. Looking to the South/East during the morning, the windsocks are slightly tilted, indicating the presence of a light wind from the South/West. The MET mast measured the temperature, pressure and wind speed at the Pathfinder Landing Site. During the mission, the instrument returned 8,5 million individual measurements from the Surface of Mars".Gen 25, 2005
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SOU-SOL011-marspath_sunset4.jpgClouds in the Martian sunset (True Colors; credits: NASA/JPL)122 visiteUn bellissimo e "veritiero" (a quanto dicono alla NASA) tramonto Marziano a colori. Questa la caption originale all'immagine, ripresa dalla Sonda Pathfinder nel 1997: "You've had a hard day rolling past Martian rocks, so now just relax your APXS and enjoy the Martian Sunset. The above pictures taken by Mars Pathfinder highlight how clouds vary during the end of a Martian day. The Atmosphere on Mars is much thinner than on Earth and dominated by CO2 rather than Nitrogen. Clouds on Mars can be Water or Carbon Dioxide based, depending on conditions, whereas Earth's clouds are all water based. At night the temperature at Sagan Memorial Station will dip from about -15 degrees Celsius (+4 Fahrenheit) to -77 degrees Celsius (-107 Fahrenheit). Temperatures only this cold won't bother Sojourner".
Dati interessanti, senza dubbio. Voi che ne dite? I colori Vi sembrano veritieri?Ott 14, 2004
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SOU-SOL008.jpgMars Panorama from Pathfinder (Carl Sagan Station) - Soles 8, 9 and 10 (Enhanced Natural Colors - top image - and Natural Colors - bottom image -; credits: NASA/JPL-Caltech)100 visiteAncora un bel panorama di Marte, così come lo vedremmo se fossimo seduti accanto alla Sonda Soujourner. Le considerazioni da svolgere sono le solite. In questo caso Vi offriamo il commento originale al frame: "Each of these panoramic views is a controlled mosaic of approximately 300 IMP images covering 360° of azimuth and elevations from approximately 4° above the horizon to 45° below it. Simultaneous adjustment of orientations of all images has been performed to minimize discontinuities between images. Mosaics have been highpass-filtered and contrast-enhanced to improve discrimination of details without distorting relative colors overall.
TOP IMAGE: Enhanced true-color image created from the "Gallery Pan" sequence, acquired on Soles 8-10 so that Local Solar Time (LST) increases nearly continuously from about 10:00 (right edge) up to about 12:00 (left). BOTTOM IMAGE: Anaglyphic stereoimage created from the "Monster Pan" sequence, acquired in 4 sections between about 8:30 and 15:00 LST on Sol 3".Set 16, 2004
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SOU-SOL050.jpgMars Panorama from Pathfinder (edited) - Sol 50 (Enhanced Natural Colors; credits: NASA/JPL/USGS)109 visiteUna bella veduta panoramica del Landing Site della Sonda Soujourner, corredata dall'indicazione di tutte le "aree di interesse", vicine e lontane. Da notarsi due cose: la prima attiene, come sempre, ai colori del paesaggio (incoerenti rispetto ad altre immagini simili o identiche); la seconda, i "nomi" dati dai Tecnici NASA alla maggior parte delle surface features oggetto di studio. Nomi che, come abbiamo detto in altra Sezione, sembrano essere stati estratti da giornali a fumetti per bambini. Semplificazione e volontà di rendere i dati accessibili a tutti o semplice tentativo di banalizzazione? Non è facile rispondere.
Voi cosa ne pensate?Set 16, 2004
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SOU-SOL004-Deimos_from_Pathfinder-PIA00996_modest.jpgDeimos, from Pathfinder - Sol 4177 visiteCaption NASA originale: "Mars' outermost natural satellite, Deimos, is seen from the Planet's surface in this Pathfinder image taken at night on Sol 4. This picture was acquired by the Imager for Mars Pathfinder (IMP) camera. Using IMP images of Deimos and its companion moon, Phobos, the spectral characteristics of the satellites and properties of the Martian atmosphere are determined".Ago 26, 2004
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SOU-SOL024-Sunset-PIA00920_modest~0.jpgSunset on Mars - Sol 24 (True Colors; credits: NASA/JPL)229 visiteCaption NASA:"This is a close-up of the Sunset on Sol 24 as seen by the Imager for Mars Pathfinder. The red sky in the background and the blue around the Sun are approximately as they would appear to the human eye. The color of the Sun itself is not correct - the Sun was overexposed in each of the 3 color images that were used to make this picture. The true color of the Sun itself may be near white or slightly bluish".Ago 23, 2004
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SOU-SOL016-PIA00784.jpgPre-Dawn Clouds on Mars - Sol 16 (True Colors; credits: NASA/JPL)177 visiteCaption NASA:"Pink Stratus Clouds are coming from the North/East at about 15 miles per hour (6,7 meters/second) at an approximate height of 10 miles (about 16 Km) above the Surface. The clouds consist of water ice condensed on reddish dust particles suspended in the Atmosphere. Clouds on Mars are sometimes localized and can sometimes cover entire Regions, but have not yet been observed to cover the entire Planet. The image was taken by the Imager for Mars Pathfinder (IMP) on Sol 16 about forty minutes before Sunrise showing areas of the Eastern Martian Local Horizon".Ago 23, 2004
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