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Endeavour is an impact crater located in the Meridiani Planum extraterrestrial plain within the Margaritifer Sinus quadrangle (MC-19) region of the planet Mars. Endeavour is about in diameter.〔 Using Mars Reconnaissance Orbiter data, phyllosilicate-bearing outcrops have been detected along the rim of this crater. These minerals may have formed under wet conditions in a low-acidic environment during the early history of Mars.〔 There are raised rim segments to the north, east, and southwest. The rim has become worn, rounded and degraded, with infilling of plains material in a manner similar to the Victoria crater.〔 When compared to the surrounding plains, the crater floor shows an enhanced spectral signature of basalt and hematite.〔 The interior contains two groups of dune fields. Images taken since 2008 show evidence of changes in some of the associated formations, which may be evidence of active erosion by the martian wind over a period of two to three years.〔 The plains surrounding the rim show evidence of polyhydrated sulfate.〔 The Mars Exploration Rover-B ''Opportunity'' began travelling toward this crater in August 2008,〔 with the rim coming into sight on March 7, 2009,〔 and arriving at the edge on August 9, 2011.〔 In December 2011, Opportunity Rover discovered a vein of gypsum sticking out of the soil along the rim of Endeavour crater. Tests confirmed that it contained calcium, sulfur, and water. The mineral gypsum is the best match for the data. It likely formed from mineral-rich water moving through a crack in the rock. The vein, called "Homestake," is in Mars' Meridiani plain. It could have been produced in conditions more neutral than the harshly acidic conditions indicated by the other sulfate deposits; hence this environment may have been more hospitable for a large variety of living organisms. Homestake is in a zone where the sulfate-rich sedimentary bedrock of the plains meets older, volcanic bedrock exposed at the rim of Endeavour crater.〔http://www.nasa.gov/home/hqnews/2011/dec/HQ_11-403_Mars_Rover_Gypsum.html〕 ==Nomenclature== The name of the crater, and features of it, are based on the voyage of HM Bark ''Endeavour'', a British Royal Navy research vessel commanded by Lieutenant James Cook on his first voyage of discovery, to Fiji, New Zealand and Australia from 1769 to 1771, using Australian places named by James Cook. Examples include: Cape Dromedary, Point Hicks, Byron Bay, Cape Tribulation, Cape Byron, and Cape York.〔(NASA Mars Rover Seeing Destination in More Detail ), NASA media release, 29 June 2010, accessed 25 July 2011〕 The purpose of the voyage was to observe the transit of Venus, to accurately measure the distance to the Sun, then to explore lands found on the return journey. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Endeavour (crater)」の詳細全文を読む スポンサード リンク
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