OLYMPUS MONS / PLANÈTE MARS PHOTOGRAPHIÉ PAR NASA VIKING ORBITER 1

NASA VIKING ORBITER  (1975-1982)
Olympus Mons (21, 229 mètres soit 21, 2 km d'altitude)
Planète Mars (Voie Lactée)

D'après une photographie prise en 1979, à 5000 km de hauteur, retouchée par IA en 2020. 

Photo originale prise par la sonde NASA Viking Orbiter 1 en 1979.

Le  volcan
Olympus Mons (21, 2 km)  nom latin pour « mont Olympe », est un volcan bouclier de la planète Mars situé dans les quadrangles d'Amazonis et de Tharsis. C'est le plus haut relief connu du système solaire, culminant à 21 229 mètres au-dessus du niveau de référence martien selon les mesures très précises de l'altimètre laser de Mars Global Surveyor (ancienne mesure 22 500 mètres). Son impressionnant diamètre est de 648 km, c'est à dire qu'il couvrirait la plus grande partie du territoire français et Suisse s'étendant de Bordeaux à Genève et de Paris à Montélimar !
Il se trouve sur la bordure nord-ouest du renflement de Tharsis, immense soulèvement de la surface martienne, centré sur Noctis Labyrinthus et Syria Planum, dont l'extension occidentale concentre une douzaine de volcans majeurs..
L'édifice central s'élève à  deux fois et demie la hauteur de l'Everest par rapport au niveau de la mer et plus du double de celle du Mauna Kea (Hawaï) par rapport à sa base  Il possède à son sommet une caldeira complexe d'environ 80 × 60 kilomètres résultant de la coalescence d'au moins six cratères enchevêtrés, attestant de l'histoire mouvementée de la caldeira avec notamment la présence de grabens résultant de l'effondrement de la surface dans une faille.
Il est entouré d'une falaise formant un escarpement continu sur toute sa circonférence, d'une hauteur de 2 à 6 kilomètres. Au-delà de cet escarpement se trouve une zone souvent appelée « l'auréole » du volcan, constituée de crêtes et de grands blocs s'étendant jusqu'à un millier de kilomètres de la caldeira. Cela met en évidence l'expansion et la modification de la surface liées à l'activité glaciaire.
L'inclinaison des pentes du volcan est voisine de 5 degrés en moyenne, atteignant 30 degrés au niveau de l'escarpement périphérique.
À proximité de la caldeira se trouvent deux cratères d'impact. À une vingtaine de kilomètres au sud, le cratère Pangboche a un diamètre de 10,4 kilomètres. Il a été nommé par l'Union astronomique internationale en 2006 d'après une localité du Népal située à vingt kilomètres du sommet de l'Everest. C'est sur le rebord ouest de ce cratère que se trouve le point le plus haut d'Olympus Mons, à 21 229 mètres au-dessus du niveau de référence. Le cratère Karzok, situé à une quarantaine de kilomètres à l'est de la caldeira, a un diamètre de 15,6 kilomètres. Il a été nommé d'après une localité du Cachemire indien. D'autres cratères d'impact sont également visibles sur les flancs du volcan.
L'escarpement et l'auréole sont tous deux mal compris. La falaise résulterait de glissements de terrain, et l'auréole proviendrait des matériaux entassés au bas de ces glissements. Les coulées de lave s'étendent au-delà de l'escarpement. L'escarpement qui entoure la montagne à sa base aurait été formé par des glissements de terrain induits par une fonte massive du permafrost11 ou par un soulèvement tectonique. Les structures linéaires en forme de crêtes présentes autour du volcan au-delà de l'escarpement seraient, quant à elles, des dykes mis en place après les dernières coulées de lave ayant atteint la base du volcan. Son premier nom, Nix Olympica, en français « Neige de l'Olympe », lui avait été donné par l'astronome italien Giovanni Schiaparelli (1835-1910). 

La mission
NASA Viking Orbiter 1 était le premier des deux engins spatiaux (avec Viking 2) envoyés sur Mars dans le cadre du programme Viking de la NASA. Le 20 juillet 1976, il est devenu le deuxième vaisseau spatial à atterrir en douceur sur Mars, et le premier à réussir sa mission. (Le premier vaisseau spatial à atterrir en douceur sur Mars était le Mars 3 de l'Union soviétique le 2 décembre 1971, qui a cessé de transmettre après 14,5 secondes.) Viking 1 détenait le record de la plus longue mission de surface de Mars de 2307 jours (plus de 6 1⁄ 4 ans) ou 2245 jours solaires martiens, jusqu'à ce que ce record soit battu par le rover Opportunity le 19 mai 2010. Après le lancement à l'aide d'un lanceur Titan/Centaur le 20 août 1975 et une croisière de 11 mois vers Mars, l'orbiteur a commencé à renvoyer des images globales de Mars environ 5 jours avant l'insertion en orbite. L'orbiteur Viking 1 a été inséré dans l'orbite de Mars le 19 juin 1976 et ajusté à une orbite de certification de site de 1513 x 33 000 km, 24,66 h le 21 juin. L'atterrissage sur Mars était prévu pour le 4 juillet 1976, le bicentenaire des États-Unis, mais l'imagerie du site d'atterrissage principal a montré qu'il était trop difficile pour un atterrissage en toute sécurité. L'atterrissage a été retardé jusqu'à ce qu'un site plus sûr soit trouvé et a eu lieu à la place le 20 juillet, le septième anniversaire de l'alunissage d'Apollo 11. L'atterrisseur s'est séparé de l'orbiteur à 08:51 UTC et a atterri à Chryse Planitia à 11:53:06 UTC. C'était la première tentative des États-Unis d'atterrir sur Mars.
Les instruments de l'orbiteur se composaient de deux caméras vidicon pour l'imagerie (VIS), d'un spectromètre infrarouge pour la cartographie de la vapeur d'eau (MAWD) et de radiomètres infrarouges pour la cartographie thermique (IRTM). La mission principale de l'orbiteur s'est terminée au début de la conjonction solaire le 5 novembre 1976.
La mission prolongée a commencé le 14 décembre 1976, après la conjonction solaire. Les opérations comprenaient des approches rapprochées de Phobos en février 1977. Le périastre a été réduit à 300 km le 11 mars 1977. Des ajustements mineurs d'orbite ont été effectués occasionnellement au cours de la mission, principalement pour modifier le taux de marche - le taux auquel la longitude aréocentrique changé à chaque orbite, et le périastre a été porté à 357 km le 20 juillet 1979. Le 7 août 1980, Viking 1 Orbiter manquait de gaz de contrôle d'attitude et son orbite a été portée de 357 × 33943 km à 320 × 56000 km pour éviter l'impact avec Mars et une éventuelle contamination jusqu'en 2019. Les opérations ont pris fin le 17 août 1980, après 1485 orbites. Une analyse de 2009 a conclu que, même si la possibilité que Viking 1 ait eu un impact sur Mars ne pouvait être exclue, il était très probablement toujours en orbite. Plus de 57 000 images ont été renvoyées sur Terre.

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2023 - Gravir les montagnes en peinture...
Un blog de Francis Rousseau

 

OLYMPUS MONS (ON MARS) PHOTOGRAPHED BY NASA MARS GLOBAL SURVEYOR

NASA MARS GLOBAL SURVEYOR  (1996-2007)
Olympus Mons (21, 230m - 69,650ft)
Mars (Solar system)

The Volcano
Olympus Mons (21, 230m / 21, 2 km-  69,650 ft /1 3 mi) is a very large shield volcano located on the planet Mars,  the largest volcano in the solar system. The massive Martian mountain towers high above the surrounding plains of the red planet, and may be biding its time until the next eruption.By one measure, it has a height of nearly 22 km (13.6 mi). Olympus Mons stands about two and a half times as tall as Mount Everest's height above sea level. It is the youngest of the large volcanoes on Mars, having formed during Mars's Hesperian Period. It had been known to astronomers since the late 19th century as the albedo feature Nix Olympica (Latin for "Olympic Snow"). Its mountainous nature was suspected well before space probes confirmed its identity as a mountain.

The volcano is located in Mars's western hemisphere at approximately 18.65°N 226.2°E, just off the northwestern edge of the Tharsis bulge. The western portion of the volcano lies in the Amazonis quadrangle (MC-8) and the central and eastern portions in the adjoining Tharsis quadrangle (MC-9).

Two impact craters on Olympus Mons have been assigned provisional names by the International Astronomical Union. They are the 15.6 km (9.7 mi)-diameter Karzok crater (18°25′N 131°55′W) and the 10.4 km (6.5 mi)-diameter Pangboche crater (17°10′N 133°35′W). The craters are notable for being two of several suspected source areas for shergottites, the most abundant class of Martian meteorites. Olympus Mons and a few other volcanoes in the Tharsis region stand high enough to reach above the frequent Martian dust-storms recorded by telescopic observers as early as the 19th century. The astronomer Patrick Moore pointed out that Schiaparelli (1835–1910) "had found that his Nodus Gordis and Olympic Snow [Nix Olympica] were almost the only features to be seen" during dust storms, and "guessed correctly that they must be high". The Mariner 9 spacecraft arrived in orbit around Mars in 1971 during a global dust-storm. The first objects to become visible as the dust began to settle, the tops of the Tharsis volcanoes, demonstrated that the altitude of these features greatly exceeded that of any mountain found on Earth, as astronomers expected. Observations of the planet from Mariner 9 confirmed that Nix Olympica was not just a mountain, but a volcano. Ultimately, astronomers adopted the name Olympus Mons for the albedo feature known as Nix Olympica.

The mission
Mars Global Surveyor (MGS) was an American robotic spacecraft developed by NASA's Jet Propulsion Laboratory and launched November 7, 1996. Mars Global Surveyor was a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface. As part of the larger Mars Exploration Program, Mars Global Surveyor performed monitoring relay for sister orbiters during aerobraking, and it helped Mars rovers and lander missions by identifying potential landing sites and relaying surface telemetry.
It completed its primary mission in January 2001 and was in its third extended mission phase when, on 2 November 2006, the spacecraft failed to respond to messages and commands. A faint signal was detected three days later which indicated that it had gone into safe mode. Attempts to recontact the spacecraft and resolve the problem failed, and NASA officially ended the mission in January 2007.
The Mars Orbiter Camera (MOC) science investigation used 3 instruments: a narrow angle camera that took (black-and-white) high resolution images (usually 1.5 to 12 m per pixel) and red and blue wide angle pictures for context (240 m per pixel) and daily global imaging (7.5 km per pixel). MOC returned more than 240,000 images spanning portions of 4.8 Martian years, from September 1997 and November 2006.[6] A high resolution image from MOC covers a distance of either 1.5 or 3.1 km long. Often, a picture will be smaller than this because it has been cut to just show a certain feature. These high resolution images may cover features 3 to 10 km long. When a high resolution image is taken, a context image is taken as well. The context image shows the image footprint of the high resolution picture. Context images are typically 115.2 km square with 240 m/pixel resolution.

The Mars Orbiter Laser Altimeter, or MOLA, is an instrument on the Mars Global Surveyor (MGS), a spacecraft that was launched on November 7, 1996. The mission of MGS was to orbit Mars, and map it over the course of approximately 3 years, which it did sucessfully, completing 4 1/2 years of mapping.
Determining the height of surface features on Mars is important to mapping it. To this end, MGS carried a laser altimeter on board. This instrument, MOLA, collected altimetry data until June 30, 2001. MOLA then operated as a radiometer until October 7, 2006.
This website will explain what MOLA is and how it works, and share some of the important discoveries about Mars that have been made using MOLA data.

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2021 - Wandering Vertexes...
by Francis Rousseau

ARSIA MONS BY NASA MARS GLOBAL SURVEYOR

NASA MARS GLOBAL SURVEYOR (1996-2007) 

Arsia Mons (17, 761 m  17 / - 58, 721ft / 11 mi)

MARS 

1. In Arsia Mons Spiral Cloud, June 19, 2001 

2. In Possible caves of Arsia Mons, HiRISE image, Laszlo P. Keszthelyi, August 9, 2007  

The mountain
Arsia Mons (20,000 m / 20 km - 63, 360ft / 12mi) is the southernmost of three volcanos with Ascraeus Mons, and Pavonis Mons (collectively known as Tharsis Montes) on the Tharsis bulge near the equator of the planet Mars, the tallest volcano in the solar system, Olympus Mons, is to its northwest. Arsia Mons was named by Giovanni Schiaparelli after the legendary Roman forest of Arsia Silva.
Arsia Mons is a shield volcano with a relatively low slope and a massive caldera at its summit. It is  large enough to cover the state of New Mexico.

The caldera of Arsia Mons was formed when the mountain collapsed in on itself after its reservoir of magma was exhausted. There are many other geologic collapse features on the mountain's flanks.
The caldera floor formed around 150 millions years ago.
One of the benefits of the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) Extended Mission is the opportunity to observe how the planet's weather changes during a second full martian year. The picture  of Arsia Mons  (photo 1 above) was taken June 19, 2001  southern spring equinox occurred the same day. On this particular day (the first day of Spring), the MOC wide angle cameras documented an unusual spiral-shaped cloud within the 110 km (68 mi) diameter caldera- the summit crater- of the giant volcano. Because the cloud is bright both in the red and blue images acquired by the wide angle cameras, it probably consisted mostly of fine dust grains. The cloud's spin may have been induced by winds off the inner slopes of the volcano's caldera walls resulting from the temperature differences between the walls and the caldera floor, or by a vortex as winds blew up and over the caldera. Similar spiral clouds were seen inside the caldera for several days; we don't know if this was a single cloud that persisted throughout that time or one that regenerated each afternoon. Sunlight illuminates this scene from the left/upper left.

Dark pits on some of the Martian volcanoes have been speculated to be entrances into caves . A HiRISE image (cf. photo 2 above), looking essentially straight down, saw only darkness in this pit. This time the pit was imaged from the west. Since the picture was taken at about 2:30 p.m. local (Mars) time,  August 9, 2007, the sun was also shining from the west. We can see the eastern wall of the pit catching the sunlight. This confirms that this pit is essentially a vertical shaft cut through the lava flows on the flank of the volcano. Such pits form on similar volcanoes in Hawaii and are called "pit craters." They generally do not connect to long open caverns but are the result of deep underground collapse. From the shadow of the rim cast onto the wall of the pit NASA could calculate that the pit is at least 178 meters - 584 feet deep. The pit is 150 x 157 meters (492 x 515 feet) across. 

The mission
Mars Global Surveyor (MGS) was an American robotic spacecraft developed by NASA's Jet Propulsion Laboratory and launched November 7, 1996. Mars Global Surveyor was a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface. As part of the larger Mars Exploration Program, Mars Global Surveyor performed monitoring relay for sister orbiters during aerobraking, and it helped Mars rovers and lander missions by identifying potential landing sites and relaying surface telemetry.
It completed its primary mission in January 2001 and was in its third extended mission phase when, on 2 November 2006, the spacecraft failed to respond to messages and commands. A faint signal was detected three days later which indicated that it had gone into safe mode. Attempts to recontact the spacecraft and resolve the problem failed, and NASA officially ended the mission in January 2007.
The Mars Orbiter Camera (MOC) science investigation used 3 instruments: a narrow angle camera that took (black-and-white) high resolution images (usually 1.5 to 12 m per pixel) and red and blue wide angle pictures for context (240 m per pixel) and daily global imaging (7.5 km per pixel). MOC returned more than 240,000 images spanning portions of 4.8 Martian years, from September 1997 and November 2006.[6] A high resolution image from MOC covers a distance of either 1.5 or 3.1 km long. Often, a picture will be smaller than this because it has been cut to just show a certain feature. These high resolution images may cover features 3 to 10 km long. When a high resolution image is taken, a context image is taken as well. The context image shows the image footprint of the high resolution picture. Context images are typically 115.2 km square with 240 m/pixel resolution.

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2019 - Wandering Vertexes...

by Francis Rousseau 

PAVONIS MONS BY NASA MARS GLOBAL SURVEYOR

 NASA MARS GLOBAL SURVEYOR  (1996-2007), 

Pavonis Mons (14,000m / 14km - 46,000ft / 8,7 mi) 

MARS

The mountain 

Pavonis Mons (14,000m / 14km - 46,000ft / 8,7 mi)  latin for "peacock mountain" is a large shield volcano located in the Tharsis region of the planet Mars. It is the middle member of a chain of three volcanic mountains (collectively known as the Tharsis Montes) that straddle the Martian equator between longitudes 235°E and 259°E. The volcano was discovered by the Mariner 9 spacecraft in 1971 and was originally called Middle Spot. Its name formally became Pavonis Mons in 1973.

Using NASA Mars Global Surveyor  and Odyssey data, combined with developments in the study of glaciers, scientists suggest that glaciers once existed on Pavonis Mons and probably still do to some extent.  Evidence for this includes concentric ridges (moraines "dropped" by glaciers), a knobby area (caused by ice sublimating), and a smooth section that flows over other deposits (debris-covered glacial ice). The ice could have been deposited when the tilt of Mars changed the climate, thereby causing more moisture to be present in the atmosphere. Studies suggest the glaciation happened in the Late Amazonian period, the most recent period in Mars chronology. Multiple stages of glaciation probably occurred. The ice present today represents one more resource for possible future colonization of the planet.

The mission
Mars Global Surveyor (MGS) was an American robotic spacecraft developed by NASA's Jet Propulsion Laboratory and launched November 7, 1996. Mars Global Surveyor was a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface.  As part of the larger Mars Exploration Program, Mars Global Surveyor performed monitoring relay for sister orbiters during aerobraking, and it helped Mars rovers and lander missions by identifying potential landing sites and relaying surface telemetry.
It completed its primary mission in January 2001 and was in its third extended mission phase when, on 2 November 2006, the spacecraft failed to respond to messages and commands. A faint signal was detected three days later which indicated that it had gone into safe mode. Attempts to recontact the spacecraft and resolve the problem failed, and NASA officially ended the mission in January 2007.
The Mars Orbiter Camera (MOC) science investigation used 3 instruments: a narrow angle camera that took (black-and-white) high resolution images (usually 1.5 to 12 m per pixel) and red and blue wide angle pictures for context (240 m per pixel) and daily global imaging (7.5 km per pixel). MOC returned more than 240,000 images spanning portions of 4.8 Martian years, from September 1997 and November 2006.[6] A high resolution image from MOC covers a distance of either 1.5 or 3.1 km long. Often, a picture will be smaller than this because it has been cut to just show a certain feature. These high resolution images may cover features 3 to 10 km long. When a high resolution image is taken, a context image is taken as well. The context image shows the image footprint of the high resolution picture. Context images are typically 115.2 km square with 240 m/pixel resolution.

ASCRAEUS MONS SEEN BY NASA MARS RECONNAISSANCE ORBITER

NASA MARS RECONNAISSANCE ORBITER (2005-2015) 

Ascraeus mons (18, 225m / 18, 1 kms- 50, 793 ft / 11, 1mi) 

Planet Mars

1.  In Ascraeus mons, HiRISE camera ,Mars Reconnaissance Orbiter (MRO); November 2010

2.  In  Colorized MOLA topography of Ascraeus Mons, 2006   

The mountain 
Ascraeus mons (18, 225m / 18kms- 50, 793 ft / 11, 1mi)  is a large shield volcano located in the Tharsis region of the planet Mars. It is the northernmost and tallest of three shield volcanoes collectively known as the Tharsis Montes. The volcano's location corresponds to the classical albedo feature Ascraeus Lacus.
Ascraeus Mons was discovered by the Mariner 9 spacecraft in 1971. The volcano was originally called North Spot because it was the northernmost of only four spots visible on the surface due to a global dust storm that was then enshrouding the planet. As the dust cleared, the spots were revealed to be extremely tall volcanoes whose summits had projected above the dust-laden, lower atmosphere.
The volcano is located in the southeast-central portion of the Tharsis quadrangle at 11.8°N, 255.5°E in Mars' western hemisphere.  Ascraeus Mons is roughly 480 km in diameter and is the second highest mountain on Mars, with a summit elevation of 18.1 km ! The volcano has a very low profile with an average flank slope of 7°. Slopes are steepest in the middle portion of the flanks, flattening out toward the base and near the top where a broad summit plateau and caldera (collapse crater) complex are located.
Volcanic vents, located on the northeastern and southwestern edges of the volcano, are sources for broad lava aprons, or fans, that bury nearby portions of the volcano and extend over 100 km out into the surrounding plains.  The southwest-northeast orientation of the aprons matches the orientation of the Tharsis Montes, suggesting that a major fissure or rift in the Martian crust is responsible for the orientation of both the aprons and the Tharsis Montes chain. The presence of the lava aprons causes some disagreement in the actual dimensions of the volcano.
Like most of the Tharsis region, Ascraeus Mons has a high albedo (reflectivity) and low thermal inertia, indicating that the volcano and surrounding areas are covered with large amounts of fine dust.  The dust forms a mantle over the surface that obscures or mutes much of the fine-scale topography and geology of the region. Tharsis is probably dusty because of its high elevations. The atmospheric density is too low to mobilize and remove dust once it is deposited.
Ascraeus Mons is surrounded by lava flow plains that are mid to late Amazonian in age. The elevation of the plains averages about 3 km above datum (Martian "sea" level), giving the volcano an average vertical relief of 15 km.  However, the elevation of the plains varies considerably. The plains northwest of the volcano are less than 2 km in elevation. The plains are highest (>3 km) southeast of the volcano.
The lava plains northwest of Ascraeus Mons are notable for having two dark collapse pits photographed by the HiRISE camera on the Mars Reconnaissance Orbiter (MRO) in November 2010 (image above) . The pits resemble those imaged around Arsia Mons by the Mars Odyssey spacecraft. The two pits measure about 180 and 310 m wide, and the larger pit is approximately 180 meters deep. The eastern walls of the pits consist of steep, overhanging ledges. The bottoms of both pits contain sediments and large boulders.  These rimless pit craters are believed to form by collapse of surface material into a subsurface void created either by a dike or lava tube. They are analogous to volcanic pit craters on Earth, such as the Devil's Throat crater on the upper east rift zone of Kilauea Volcano, Hawaii.  In some cases, they may mark skylights/entrances to subsurface lava caves.

The camera
The image above, has been captured by the HiRISE  (High Resolution Imaging Science Experiment) camera aboard NASA’s Mars Reconnaissance Orbiter. The 65 kg (143 lb), $40 million USD instrument was built under the direction of the University of Arizona's Lunar and Planetary Laboratory by Ball Aerospace & Technologies Corp. It consists of a 0.5 m (19.7 in) aperture reflecting telescope, the largest so far of any deep space mission, which allows it to take pictures of Mars with resolutions of 0.3 m/pixel (about 1 foot), resolving objects below a meter across.
HiRISE has imaged Mars landers on the surface, including the ongoing Curiosity and Opportunity rover missions.
HiRISE was designed to be a High Resolution camera from the beginning. It consists of a large mirror, as well as a large CCD camera. Because of this, it achieves a resolution of 1 microradian, or 0.3 meter at a height of 300 km. (For comparison purposes, satellite images on Google Mars are available to 1 meter). It can image in three color bands, 400–600 nm (blue-green or B-G), 550–850 nm (red) and 800–1,000 nm (near infrared or NIR).
HiRISE incorporates a 0.5-meter primary mirror, the largest optical telescope ever sent beyond Earth's orbit. The mass of the instrument is 64.2 kg.
Red color images are at 20,048 pixels wide (6 km in a 300 km orbit), and Green-Blue and NIR are at 4,048 pixels wide (1.2 km). These are gathered by 14 CCD sensors, 2048 x 128 pixels. HiRISE's onboard computer reads out these lines in time with the orbiter's ground speed, meaning the images are potentially unlimited in height. Practically this is limited by the onboard computer's 28 Gbit (3.5 GByte) memory capacity. The nominal maximum size of red images (compressed to 8 bits per pixel) is about 20,000 × 126,000 pixels, or 2520 megapixels and 4,000 × 126,000 pixels (504 megapixels) for the narrower images of the B-G and NIR bands. A single uncompressed image uses up to 28 Gbit. However, these images are transmitted compressed, with a typical max size of 11.2 Gigabits. These images are released to the general public on the HiRISE website via a new format called JPEG 2000.
To facilitate the mapping of potential landing sites, HiRISE can produce stereo pairs of images from which the topography can be measured to an accuracy of 0.25 meter.
The HiRISE camera is designed to view surface features of Mars in greater detail than has previously been possible. It has provided a closer look at fresh martian craters, revealing alluvial fans, viscous flow features and ponded regions of pitted materials containing breccia clast.  This allows for the study of the age of Martian features, looking for landing sites for future Mars landers, and in general, seeing the Martian surface in far greater detail than has previously been done from orbit. By doing so, it is allowing better studies of Martian channels and valleys, volcanic landforms, possible former lakes and oceans, and other surface landforms as they exist on the Martian surface.
The general public is allowed to request sites for the HiRISE camera to capture (see HiWish). For this reason, and due to the unprecedented access of pictures to the general public, shortly after they have been received and processed, the camera has been termed "The People's Camera".
 The pictures can be viewed online, downloaded, or with the free HiView software.

CERAUNIUS THOLUS SEEN BY NASA MARS GLOBAL SURVEYOR

NASA MARS GLOBAL SURVEYOR  (1996-2007) 

Ceraunius Tholus (5,500 m  / 5, 5 km - 18,044 ft  / 3,4 mi)

MARS

1. In View of Ceraunius Tholus (left) and Uranius Tholus (right), Mars Orbiter Camera of 

Mars Global Surveyor, 2002

2.    In The volcanoes Ceraunius Tholus (left) and Uranius Tholus (right) showed by 

THEMIS daytime infrared image mosaic, 2012

The mountain 
Ceraunius Tholus (5,500 m -  )is a volcano on Mars located in the Tharsis quadrangle at 24.25° north latitude and 262.75° east longitude, part of the Uranius group of volcanoes. It is 130 km across, 5.5 km high and is named after a classical albedo feature name.
Ceraunius Tholus is on the Tharsis rise, also called the Tharsis bulge. Tharsis is a land of great volcanoes. Olympus Mons is the tallest known volcano. Ascraeus Mons and Pavonis Mons are at least 320 km across and are over 10 km above the plateau that they sit on. The plateau is five to four seven kilometers above the zero altitude of Mars.
Ceranius Tholus is generally believed to be a basaltic shield with the lower part buried beneath plain forming lavas. Earlier interpretations suggested that it is a stratovolcano.  The slopes on Ceraunius Tholus are quite steep with an average slope of 8° with many radial erosion channels and pitted valleys extending from just below the rim of the caldera toward the base of the volcano. The current view is that the valleys were eroded by water.  Interesting features on Ceraunius Tholus are three large canyons at the northwest flank of Ceraunius Tholus which are up to 2.5 km wide and 300 m deep. The biggest of these three also appears to be the youngest and protrude from the lowest point of the volcanic caldera and ends at the interesting crater Rahe (an oblique impact crater with measures of 35 Ч 18 km), just north from the volcano where it formed a depositional fan. Its origin is still debatable and there are four main models proposed: fluvial action, volcanic flows, valley being a lava channel or some combination of previously mentioned models.
Ceraunius appears small compared to other larger volcanoes, but it is almost as tall as Earth's Mount Everest. The caldera of Ceranius Tholus is also dotted with many collapse pits, which are distinct from impact craters as they have no rim and vary in abundance across the caldera. Ceraunius Tholus is probably late Hesperian in age.
Some scientists believe that glaciers may have existed on many of the volcanoes in Tharsis including Olympus Mons, Ascraeus Mons, and Pavonis Mons.  Ceraunius Tholus may have even had its glaciers melt to form some temporary lakes in the past. The smoothness and flatness of the Ceraunius Tholus caldera floor suggests that in the past meltwater accumulated in a caldera lake.

The mission
Mars Global Surveyor (MGS) was an American robotic spacecraft developed by NASA's Jet Propulsion Laboratory and launched November 7, 1996. Mars Global Surveyor was a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface.  As part of the larger Mars Exploration Program, Mars Global Surveyor performed monitoring relay for sister orbiters during aerobraking, and it helped Mars rovers and lander missions by identifying potential landing sites and relaying surface telemetry.
It completed its primary mission in January 2001 and was in its third extended mission phase when, on 2 November 2006, the spacecraft failed to respond to messages and commands. A faint signal was detected three days later which indicated that it had gone into safe mode. Attempts to recontact the spacecraft and resolve the problem failed, and NASA officially ended the mission in January 2007.
The Mars Orbiter Camera (MOC) science investigation used 3 instruments: a narrow angle camera that took (black-and-white) high resolution images (usually 1.5 to 12 m per pixel) and red and blue wide angle pictures for context (240 m per pixel) and daily global imaging (7.5 km per pixel). MOC returned more than 240,000 images spanning portions of 4.8 Martian years, from September 1997 and November 2006.[6] A high resolution image from MOC covers a distance of either 1.5 or 3.1 km long. Often, a picture will be smaller than this because it has been cut to just show a certain feature. These high resolution images may cover features 3 to 10 km long. When a high resolution image is taken, a context image is taken as well. The context image shows the image footprint of the high resolution picture. Context images are typically 115.2 km square with 240 m/pixel resolution.
Source: 
- NASA data base on MGS 

OLYMPUS MONS (MARS) BY NASA VIKING PROGRAM

NASA VIKING PROGRAM (1975-1982)

Olympus Mons (21, 230m -  69,650ft) 

Planet Mars - Solar system  

1.  Image of Olympus Mons from NASA Viking 1 Orbiter in 1974 

2.  Olumpus Mons caldera from Mars Express camera on 26 May 2004 

The mountain 

Olympus Mons (21, 230m -  69,650 ft) is a very large shield volcano located on the planet Mars. By one measure, it has a height of nearly 22 km (13.6 mi). Olympus Mons stands about two and a half times as tall as Mount Everest's height above sea level. It is the youngest of the large volcanoes on Mars, having formed during Mars's Hesperian Period. It is currently the largest volcano discovered in the Solar System and had been known to astronomers since the late 19th century as the albedo feature Nix Olympica (Latin for "Olympic Snow"). Its mountainous nature was suspected well before space probes confirmed its identity as a mountain.

The volcano is located in Mars's western hemisphere at approximately 18.65°N 226.2°E, just off the northwestern edge of the Tharsis bulge. The western portion of the volcano lies in the Amazonis quadrangle (MC-8) and the central and eastern portions in the adjoining Tharsis quadrangle (MC-9).

Two impact craters on Olympus Mons have been assigned provisional names by the International Astronomical Union. They are the 15.6 km (9.7 mi)-diameter Karzok crater (18°25′N 131°55′W) and the 10.4 km (6.5 mi)-diameter Pangboche crater (17°10′N 133°35′W). The craters are notable for being two of several suspected source areas for shergottites, the most abundant class of Martian meteorites.

Olympus Mons and a few other volcanoes in the Tharsis region stand high enough to reach above the frequent Martian dust-storms recorded by telescopic observers as early as the 19th century. The astronomer Patrick Moore pointed out that Schiaparelli (1835–1910) "had found that his Nodus Gordis and Olympic Snow [Nix Olympica] were almost the only features to be seen" during dust storms, and "guessed correctly that they must be high".
The Mariner 9 spacecraft arrived in orbit around Mars in 1971 during a global dust-storm. The first objects to become visible as the dust began to settle, the tops of the Tharsis volcanoes, demonstrated that the altitude of these features greatly exceeded that of any mountain found on Earth, as astronomers expected. Observations of the planet from Mariner 9 confirmed that Nix Olympica was not just a mountain, but a volcano. Ultimately, astronomers adopted the name Olympus Mons for the albedo feature known as Nix Olympica.

The program

The Viking program consisted of a pair of American space probes sent to Mars, Viking 1 and Viking 2. Each spacecraft was composed of two main parts: an orbiter designed to photograph the surface of Mars from orbit, and a lander designed to study the planet from the surface. The orbiters also served as communication relays for the landers once they touched down.
The Viking program grew from NASA's earlier, even more ambitious, Voyager Mars program, which was not related to the successful Voyager deep space probes of the late 1970s. Viking 1 was launched on August 20, 1975, and the second craft, Viking 2, was launched on September 9, 1975, both riding atop Titan III-E rockets with Centaur upper stages. Viking 1 entered Mars orbit on June 19, 1976, with Viking 2 following suit on August 7.
After orbiting Mars for more than a month and returning images used for landing site selection, the orbiters and landers detached; the landers then entered the Martian atmosphere and soft-landed at the sites that had been chosen. The Viking 1 lander touched down on the surface of Mars on July 20, 1976, and was joined by the Viking 2 lander on September 3. The orbiters continued imaging and performing other scientific operations from orbit while the landers deployed instruments on the surface.
The project cost roughly 1 billion USD in 1970s dollars, equivalent to about 11 billion USD in 2016 dollars. It was highly successful and formed most of the body of knowledge about Mars through the late 1990s and early 2000s.
Source :
 - NASA- JPL-CALTECH