Endeavour as viewed from Mars orbitThe tip of the bottom right of the star is the approximate location of the crater Endeavour on MarsOpportunity images a Martian whirlwind on the floor of Endeavour (April 2016)
Endeavour is animpact crater located in theMeridiani Planum extraterrestrial plain within theMargaritifer Sinus quadrangle (MC-19) region of the planetMars. Endeavour is about 22 kilometers (14 mi) in diameter.[1] UsingMars Reconnaissance Orbiter data,phyllosilicate-bearing outcrops have been detected along its rim. These minerals may have formed under wet conditions in a low-acidic environment during the early history of Mars.[5] 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 theVictoria crater.[6]
When compared to the surrounding plains, the crater floor shows an enhanced spectral signature ofbasalt andhematite.[7] 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.[6] The plains surrounding the rim show evidence of polyhydrated sulfate.[7]
TheMars Exploration Rover-BOpportunity began travelling toward this crater in August 2008,[1] with the rim coming into sight on March 7, 2009,[8] and arriving at the edge on August 9, 2011.[9]
Endeavour averages about 200 to 300 metres (660 to 980 ft) deep, with an area in its southeast that goes down to 500 metres (1,600 ft) deep, according to a publication calledDegradation of Endeavour Crater, Mars by the Smithsonian Institution.[10] The south-west depression goes down to an elevation of −1,980 metres (−6,500 ft), the horse-shoe shaped depression sits in the south-east quadrant and is around minus −1,800 to −1,900 metres (−5,900 to −6,200 ft) elevation, which is about 400 metres (1,300 ft) below the surrounding plains.[10] It is noted that the crater has undergone various erosion processes, with wind being one cause.[10]
TheInternational Astronomical Union named the crater after a town inCanada,Endeavour, Saskatchewan.[3] The name was approved on 20 October 2008.[11] Due to rules for naming craters, it is officially named after the Canadian town, but the reason this name was proposed was because rover team was using informal nicknames based on a voyage of HMSEndeavour.[4]
The crater is understood by the 2010s to have two main rock types, the Shoemaker Formation and the Matijevic Formation.[13] It has been classified as acomplex crater and it is thought to be so old many of its features have been worn away.[13] Some questions were raised about the tilt of the rim, however understanding is hampered by a lack of knowledge about Martian impact craters: Endeavour was the largest Martian impact crater up to that time to be studied that closely.[13] An example of the difficulty of studying Mars features is also apparent withOrcus Patera, which has various volcanic, tectonic, or cratering events explanations for its formation.[14] One famous Mars realization was that what was then calledNix Olympica was a volcano, and then renamedOlympus Mons thanks toMariner 9 orbiter observations in the early 1970s.[15] Endeavour was identified as having clay minerals, as detected from orbit byMars Reconnaissance Orbiter, which according to theories at that time indicated rock from an older, wetter, time period on Mars.[16] This type of rock is different from what prevails in other areas of surrounding plains.[16]
What is expected to be a fluid-carved gully was identified at Endeavour, probably water.[17] This gully is targeted for exploration by the MER-B rover mission as of October 2016.[17] It reached the gully in 2017 and it was named Perseverance Valley
Colored for minerals.Opportunity traverse is dated to 2010 while it was still on its way to Endeavour. The coloring is based on geological information as observed by theMars Reconnaissance OrbiterCRISM instrument
Western rim of the crater as seen from Cape York looking south, with the first ridge being Solander PointHazcam image ofBotany Bay andSolander Point (2013)MER-B NavCam image Sol 4959[18] Start of January 2018, looking along the rim of Endeavour south of the gully (P.V.)Annotated map various locations on Endeavour's western rim
Explored in by the MER-B rover, several locations including the crater Spirit of St. Louis with Lindberg Mound, Marathon Valley, Lewis and Clark pass, and Spirit mound among other features on or very near the Western rim
Throughout 2017,Opportunity worked its way south along the Western rim as it moved towards the gully, which the team namedPerseverance Valley in April 2017.[22][25]
Traverse map up to 4836 (September 12, 2017)[26]HiRise image from MRO, was laid over 3-D topographic map of the terrain, with 5-fold vertical exaggeration; view looking west on to Perseverance Valley on the western rim of Endeavour (February 15, 2018)[27]
Arrival at Spirit Point at Endeavour, in the distance is the crater floor and on the other side the eastern rim segmentsEastern rim of Endeavour, the B&W swath is about 5 km across and the color swath 1 km[28]Part of the Eastern rim as seen by MER-B
MER-B has had such new discoveries at the crater, that the rover team compared Endeavour to the equivalent of a second landing site forOpportunity.[29][30] For example, On sol 2692 (August 22, 2011) the rover began examining Tisdale 2, a large ejecta block. "This is different from any rock ever seen on Mars," saidSteve Squyres, principal investigator forOpportunity at Cornell University in Ithaca, New York.[29]
Opportunity's traverse up to March 2015 from its landing site to Endeavour. It has traversed south along the Western rim and orbiting spacecraft have help collect data on the rim, which in turn allows the rover to more closely investigateSelf-portrait ofOpportunity near Endeavour on the surface ofMars (January 6, 2014).
On March 7, 2009 (sol 1,820),Opportunity first imaged the rim of Endeavour after driving about 3.2 kilometers (2.0 mi) since it left Victoria in August 2008.[8][35]Opportunity also imagedthe crater Iazu, which is about 38 kilometers (24 mi) away and about 7 kilometers (4.3 mi) in diameter.[35] At that time,Opportunity was 12 kilometers (7.5 mi) from Endeavour as the Martian crow flies, but to avoid hazards, it was estimated that it would take about 30% more driving distance than that to reach Endeavour.[8] Based on the amount of time it had taken to drive from Victoria, it was estimated that this journey would take over one Martian year (23 months).[8] On May 5, 2010, to avoid hazardous dune fields along the direct path between Victoria and Endeavour, the charted route between the two craters was extended to an estimated 19 kilometers.[36]
On September 8, 2010, it was announced thatOpportunity had reached the halfway point of the 19-kilometer journey between Victoria and Endeavour.[37] By June 28, 2011,Opportunity was just under 2 kilometers (1.2 mi) from landfall at the rim of Endeavour.[38]
On August 4, 2011,Opportunity was only 120 meters (390 ft) from the rim of Endeavour,[39] and on August 9, 2011Opportunity arrived at the west rim near Spirit Point to study outcrops never seen before.[9]
When it arrived it explored the northwest outcrops atCape York (Mars) of the crater before heading south toSolander Point and the Western rim.[40]
MER-B on Sol 2239 imaged the then distant crater rim. On this map several locations of Endeavour are identified including: Cape Tribulation, Cape Bryon, Cape Dromedary, Point Hicks, Torres Strait, and Batavia. Further south the nearby crater Iazu is also marked.Here is the view from the rover's perspective from that location noted in the above top-down view. The white lines indicate the rover'sfield of view
MER-B eventually reached Cape Tribulation, and took a panorama from its top:Opportunity's view from Cape Tribulation on the rim of Endeavour, January 22, 2015.
Opportunity's traverse up to February 2015 as it approached Spirit of St. Louis Crater and Marathon Valley, and came close to traveling the distance of a traditionalmarathon (about 26 miles or 42 km)
In December 2011,Opportunity rover discovered a vein ofgypsum sticking out of the soil along the rim of Endeavour. Tests confirmed that it containedcalcium,sulfur, andwater. 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 is called "Homestake." 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.[41][42]
In October 2016 ESA'sSchiaparelli lander attempted to re-use the provenMeridiani Planum landing site, with a landing ellipse that kisses the Endeavour crater location whereOpportunity was still functioning.[44] This allowed the opportunity forOpportunity to attempt to image the lander during its descent from the surface of Mars.[44] Contact was lost during descent
MRO Context Camera images ofSchiaparelli landing site; before (29 May 2016) and after (20 October 2016). The large black spot indicates the impact by the lander, and the white spot its parachute.[45]
Two of the seven final landing candidates for MSL were relatively near to Endeavour, one was inMiyamoto (crater) and another was south of Endeavour in southerner Meridiani.[46]Gale (crater) won the selection
Endeavour can be seen on the right side of this map about halfway down; in the bottom left is the proposed landing ellipse for MSL in the crater Miyamoto.
MER-B from 2011 to 2016 explored the Western rim of Endeavour, starting atCape York (Mars) then moving down through Botany Bay toSolander Point, along Murray Ridge moving south to Marathon Valley; in late 2016 it began moving inward to the crater floor: It then moved back to the rim and went south to gully named Perseverance Valley, leaving the Cape Tribulation section, and heading towards Cape Bryon.
A detailed-class rover traverse map by the mission, released on September 28, 2016, showing the track of the rover up to Sol 4500 as it heads deeper in EndeavourAn annotated view of the traverse to Spirit mound, October 2016
Marathon Valley as viewed by theOpportunity rover (false color;stereo; March 13, 2015).
Opportunity looks at the southern end of Cape Tribulation as it heads south, showing how the Western rim ridge[48]In March 2016, while trying to reach target on the slope of Marathon Valley in Cape Tribulation, the Mars rover attained a slope of 32 degrees, the highest angle yet for the rover since its mission began. This was so steep that dust that had accumulated on its top panels began to flow downward.[49]
This crater sits at the Western mouth of Marathon Valley, south Cape Tribulation on the western rim of Endeavour. It was visited by the MER-BOpportunity rover in May 2015.[50]
In May 2015 the rover visited what was dubbed Spirit of St. Louis, a shallow crater about 110 feet (34 meters) long and 80 feet (24 meters) across. In its center is Lindbergh Mound, about 2-3 meters (yards) high. This version of the panorama is annotated and infalse color[51]
Perseverance Valley is an erosion network in the Cape Bryon section of the Western Endeavour rim.[22] It was named in April 2017 by the MER-B team, which previously referred to it as the gully.[22]
The proposed landing ellipse in Miyamoto when it was one of seven finalists under consideration as a landing site for MSL.[46] Endeavour can be seen on the right side of the map, the top of three medium-sized craters in a north–south line. This map is color-coded based on elevation.
Map showing the location of Endeavour and other, nearby features
^Wray, J. J.; et al. (November 2009), "Phyllosilicates and sulfates at Endeavour Crater, Meridiani Planum, Mars",Geophysical Research Letters,36 (21): L21201,Bibcode:2009GeoRL..3621201W,doi:10.1029/2009GL040734{{citation}}: CS1 maint: multiple names: authors list (link)
^abChojnacki, M.; Burr, D. M.; Moersch, J. (March 2010), "Recent Dune Changes at Endeavour Crater, Meridiani Planum, Mars, from Orbital Observations",41st Lunar and Planetary Science Conference, held March 1–5, 2010, The Woodlands, Texas, p. 2326,Bibcode:2010LPI....41.2326C{{citation}}: CS1 maint: location missing publisher (link)
^abChojnacki, M.; Moersch, J.; Wray, J. J.; Burr, D. M. (March 2010), "The Stratigraphy, Composition and Thermophysical Properties of Endeavour Crater, Meridiani Planum, Mars, from Orbital Remote Sensing",41st Lunar and Planetary Science Conference, held March 1–5, 2010, The Woodlands, Texas, p. 2175,Bibcode:2010LPI....41.2175C{{citation}}: CS1 maint: location missing publisher (link)
