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 22 kilometers (14 mi) in diameter.[1] Using Mars 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 the
Victoria crater.[6]
When compared to the surrounding plains, the crater floor shows an enhanced spectral signature of
basalt and
hematite.[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]
The
Mars Exploration Rover-B Opportunity 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 called Degradation 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]
Nomenclature
The
International Astronomical Union named the crater after a town in
Canada.[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 HMS Endeavour.[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 a
complex 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 with
Orcus Patera, which has various volcanic, tectonic, or cratering events explanations for its formation.[14] One famous Mars realization was that what was then called Nix Olympica was a volcano, and then renamed
Olympus Mons thanks to
Mariner 9 orbiter observations in the early 1970s.[15] Endeavour was identified as having clay minerals, as detected from orbit by
Mars 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
Perseverance Valley, erosion network in this section of the rim, reached by MER-B in 2017[22]
Cape Dromedary
Point Hicks
Torres Strait (from the end of Point Hicks to Batavia on the southern rim)
The next rim section proceeding counter-clockwise around the crater is Batavia, on the southern end of the whole crater but East of Torres Strait
Western rim mineral map
Western rim elevation
Western rim
Western rim sections from Solander to Marathon
3492 (November 2013)
3500 to 3689 (June 2014)
3728 to 3757 (August 2014)
Roughly in the center is Ulysses crater, visited by MER-B around Sol 3790 (September 2014)[20]
3750 to 3869 (December 2014)
Ulysses crater is roughly top-center location, visited by MER-B around Sol 3790 (September 2014)[20]
3870 to 4209 (December 2015)
October 2016 (with labels)
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
to 4625 (January 2017)
to 4695 (April 2017)
Cape Tribulation and Cape Bryon
Up to 4836 (September 2017)
Throughout 2017, Opportunity worked its way south along the Western rim as it moved towards the gully, which the team named Perseverance Valley in April 2017.[22][25]
MER-B has had such new discoveries at the crater, that the rover team compared Endeavour to the equivalent of a second landing site for Opportunity.[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," said
Steve Squyres, principal investigator for Opportunity at Cornell University in Ithaca, New York.[29]
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 imaged
the 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 that Opportunity 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, 2011 Opportunity arrived at the west rim near Spirit Point to study outcrops never seen before.[9]
When it arrived it explored the northwest outcrops at
Cape York (Mars) of the crater before heading south to
Solander Point and the Western rim.[40]
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.
In December 2011, Opportunity rover discovered a vein of
gypsum sticking out of the soil along the rim of Endeavour. 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 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]
Wdowiak Ridge
A view looking north-north west with the Western and Northwest Endeavour segments
Proximity to Schiaparelli landing ellipse
In October 2016 ESA's
Schiaparelli lander attempted to re-use the proven
Meridiani Planum landing site, with a landing ellipse that kisses the Endeavour crater location where Opportunity was still functioning.[44] This allowed the opportunity for Opportunity to attempt to image the lander during its descent from the surface of Mars.[44] Contact was lost during descent
Proximity to MSL landing site candidates
Two of the seven final landing candidates for MSL were relatively near to Endeavour, one was in
Miyamoto (crater) and another was south of Endeavour in southerner Meridiani.[46]Gale (crater) won the selection
MER-B from 2011 to 2016 explored the Western rim of Endeavour, starting at
Cape York (Mars) then moving down through Botany Bay to
Solander 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.
Marathon Valley as viewed by the Opportunity rover (
false color;
stereo; March 13, 2015).
Spirit of St. Louis
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-B Opportunity 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 in
false color[51]
Above Perseverance Valley by Opportunity
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]
Context
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)