NASA MARS GLOBAL SURVEYOR (1996-2007)
Hecates Tholus (4, 500 m /4, 5km - 14,764ft /2, 79mi)
Mars (Solar System)
Photographed in october 27, 2003
The mountain
Hecates Tholus (4,500 m /4, 5km - 14,764ft /2, 79mi) is a volcano located on the planet Mars by 32.1 ° N and 150.2 ° E in the Cebrenia quadrangle. It is about 180 km wide, about 6,000 m above Elysium Planitia. This volcano has a small summit caldera about 13 km in diameter and barely 500 m deep, and a newer lateral caldera about 10 km wide. Its flanks are convex, with a slope varying from 6 ° to 3 ° from the base to the summit.
Hecates Tholus is located north-east of Elysium Mons, north of Elysium Planitia, the second largest volcanic province of Mars, which also includes Albor Tholus in the center and Apollinaris Mons in the extreme south-east.The oldest sites were dated on the flanks of Hecates Tholus around 3.4 Ga, indicating that the volcano would have formed no later than that date. The summit caldera has subsequently experienced at least three volcanic episodes, the main one around 1 Ga and two minor episodes, with no effect on the flanks, dated at about 300 Ma and 100 Ma2.
The HRSC of the Mars Express spacecraft also discovered a second caldera, located to the northwest northwest near the base of the dome, with a diameter of 10 km and corresponding to an eruption dated to about 350 Ma5. This observation campaign has also identified recent glacial deposits in the caldeira and nearby depressions, dated less than 25 Ma, which would be in sync with a period of greater obliquity suggested at that time by various similar observations. on the surface of the planet6.
Given the morphology of the building, dome-shaped with decreasing slopes from the base to the summit, it could be a stratovolcano, similar in nature to Albor Tholus.
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.
