Opportunity rover

Opportunity rover

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Opportunity, MER-B is a robotic rover on the planet Mars
Mars Rover
A Mars rover is an automated motor vehicle which propels itself across the surface of the planet Mars after landing.Rovers have several advantages over stationary landers: they examine more territory, they can be directed to interesting features, they can place themselves in sunny positions to...

, active since 2004. It is the remaining rover
Rover (space exploration)
A rover is a space exploration vehicle designed to move across the surface of a planet or other astronomical body. Some rovers have been designed to transport members of a human spaceflight crew; others have been partially or fully autonomous robots...

 in NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

's ongoing Mars Exploration Rover Mission. Launched from Earth on 7 July 2003, it landed on the Martian
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

 Meridiani Planum
Meridiani Planum
Meridiani Planum is a plain located 2 degrees south of Mars' equator , in the westernmost portion of Terra Meridiani. It hosts a rare occurrence of gray crystalline hematite...

 on 25 January 2004 at 05:05 Ground UTC (about 13:15 local time
Timekeeping on Mars
Various schemes have been used or proposed to keep track of time and date on the planet Mars independently of Earth time and calendars.Mars has an axial tilt and a rotation period similar to those of Earth. Thus it experiences seasons of spring, summer, autumn and winter much like Earth, and its...

), three weeks after its twin Spirit
Spirit rover
Spirit, MER-A , is a robotic rover on Mars, active from 2004 to 2010. It was one of two rovers of NASA's ongoing Mars Exploration Rover Mission. It landed successfully on Mars at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, Opportunity , landed on the other side of the planet...

(MER-A) touched down on the other side of the planet.

As of Sol 2700 (29 August 2011), Opportunity has continued to function effectively 30 times longer than its planned 90-sol mission, aided by solar cell cleaning event
Cleaning event
A cleaning event is a phenomenon whereby dust is removed from solar panels, particularly ones on Mars, by the action of wind. The term cleaning event is used on several NASA webpages; generally the term is used in reference to the fact that Martian winds have blown dust clear of the solar panels of...

s, and it continues to perform extensive geological analysis of Martian rocks and planetary surface features. Its twin, the Spirit rover
Spirit rover
Spirit, MER-A , is a robotic rover on Mars, active from 2004 to 2010. It was one of two rovers of NASA's ongoing Mars Exploration Rover Mission. It landed successfully on Mars at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, Opportunity , landed on the other side of the planet...

, became immobile in 2009 and in 2010 ceased communications.

Mission highlights include completion of the 90-sol (90 Martian days) mission, discovery of the first meteorite on another planet, Heat Shield Rock
Heat Shield Rock
Heat Shield Rock is a basketball-sized iron-nickel meteorite found on Mars by the Mars rover Opportunity in January 2005. The meteorite was formally named Meridiani Planum meteorite by the Meteoritical Society in October, 2005 .-Discovery:Opportunity encountered the meteorite entirely by chance,...

 (Meridiani Planum), and over two years studying Victoria crater. The rover narrowly survived dust-storms in 2007, and has reached the rim of Endeavour crater. Opportunity had driven more than 34 kilometres (21.1 mi) by 22 November 2011 (sol 2783), as preparations were being made for the coming Martian winter.

The Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...

 (JPL), a division of the California Institute of Technology
California Institute of Technology
The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...

 in Pasadena, manages the Mars Exploration Rover project for NASA's Office of Space Science in Washington, D.C.

Objectives


The scientific objectives of the Mars Exploration Rover mission are to:
  • Search for and characterize a variety of rocks and soils that hold clues to past water activity. In particular, samples sought will include those that have minerals deposited by water-related processes such as precipitation
    Precipitation (meteorology)
    In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...

    , evaporation
    Water vapor
    Water vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...

    , sedimentary cementation
    Sedimentary rock
    Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....

     or hydrothermal activity.
  • Determine the distribution and composition of minerals, rocks, and soils surrounding the landing sites.
  • Determine what geologic processes
    Geology of Mars
    The geology of Mars is the scientific study of the surface, crust, and interior of the planet Mars. It emphasizes the composition, structure, history, and physical processes that shape the planet. It is fully analogous to the field of terrestrial geology. In planetary science, the term geology is...

     have shaped the local terrain and influenced the chemistry. Such processes could include water or wind erosion, sedimentation, hydrothermal mechanisms, volcanism, and cratering.
  • Perform calibration and validation of surface observations made by Mars Reconnaissance Orbiter
    Mars Reconnaissance Orbiter
    Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

     instruments. This will help determine the accuracy and effectiveness of various instruments that survey Martian geology
    Geology of Mars
    The geology of Mars is the scientific study of the surface, crust, and interior of the planet Mars. It emphasizes the composition, structure, history, and physical processes that shape the planet. It is fully analogous to the field of terrestrial geology. In planetary science, the term geology is...

     from orbit.
  • Search for iron-containing minerals, identify and quantify relative amounts of specific mineral types that contain water or were formed in water, such as iron-bearing carbonates.
  • Characterize the mineralogy
    Mineralogy
    Mineralogy is the study of chemistry, crystal structure, and physical properties of minerals. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their utilization.-History:Early writing...

     and textures of rocks and soils and determine the processes that created them.
  • Search for geological clues to the environmental conditions
    Environmental science
    Environmental science is an interdisciplinary academic field that integrates physical and biological sciences, to the study of the environment, and the solution of environmental problems...

     that existed when liquid water was present.
  • Assess whether those environments were conducive to life.


During the next two decades, NASA will continue to conduct missions to address whether life ever arose on Mars. The search begins with determining whether the Martian environment was ever suitable for life. Life, as we understand it, requires water, so the history of water on Mars is critical to finding out if the Martian environment was ever conducive to life. Although the Mars Exploration Rovers do not have the ability to detect life directly, they are offering very important information on the habitability of the environment in the planet's history.

Design and construction


Opportunity (along with its twin, Spirit) is a six-wheeled, solar-powered robot standing 1.5 m (4.9 ft) high, 2.3 m (7.5 ft) wide and 1.6 m (5.2 ft) long and weighing 180 kg (400 lb). Six wheels on a rocker-bogie
Rocker-bogie
The Rocker-Bogie system is the suspension arrangement used in the Mars rovers introduced for the Mars Pathfinder and also used on the Mars Exploration Rover and Mars Science Laboratory missions. It is currently NASA's favored design....

 system enable mobility over rough terrain. Each wheel has its own motor, the vehicle is steered at front and rear and is designed to operate safely at tilts of up to 30 degrees. Maximum speed is 50 mm/s (2 in/s) although average speed is about a fifth of this. Both Spirit
Spirit rover
Spirit, MER-A , is a robotic rover on Mars, active from 2004 to 2010. It was one of two rovers of NASA's ongoing Mars Exploration Rover Mission. It landed successfully on Mars at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, Opportunity , landed on the other side of the planet...

 and Opportunity have pieces of the fallen World Trade Center
World Trade Center
The original World Trade Center was a complex with seven buildings featuring landmark twin towers in Lower Manhattan, New York City, United States. The complex opened on April 4, 1973, and was destroyed in 2001 during the September 11 attacks. The site is currently being rebuilt with five new...

's metal on them which were "turned into shields to protect cables on the drilling mechanisms".

Solar arrays generate about 140 watts for up to four hours per Martian day (sol) while rechargeable lithium ion batteries store energy for use at night. Opportunity's onboard computer uses a 20 MHz RAD6000 CPU with 128 MB of DRAM, 3 MB of EEPROM, and 256 MB of flash memory. The rover's operating temperature
Operating temperature
An operating temperature is the temperature at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the...

 ranges from −40 °C to +40 °C (−40 °F to 104 °F) and radioisotope heaters
Radioisotope heater unit
Radioisotope heater units are small devices that provide heat through radioactive decay. They are similar to tiny radioisotope thermoelectric generators , and normally provide about one watt of heat each, derived from the decay of a few grams of plutonium 238, although other radioactive isotopes...

 provide a base level of heating, assisted by electrical heaters when necessary. A gold film and a layer of silica aerogel
Aerogel
Aerogel is a synthetic porous material derived from a gel, in which the liquid component of the gel has been replaced with a gas. The result is a solid with extremely low density and thermal conductivity...

 provide insulation.

Communications depends on an omnidirectional low-gain antenna communicating at a low data rate and a steerable high-gain antenna, both in direct contact with Earth. A low gain antenna is also used to relay data to spacecraft orbiting Mars.

Fixed science/engineering instruments include:
  • Panoramic Camera (Pancam) – examines the texture, color, mineralogy, and structure of the local terrain.
  • Navigation Camera (Navcam) – monochrome with a higher field of view but lower resolution, for navigation and driving.
  • Miniature Thermal Emission Spectrometer (Mini-TES)
    Mini-TES
    ]The Miniature Thermal Emission Spectrometer is an infrared spectrometer used for detecting the composition of a material from a distance...

     – identifies promising rocks and soils for closer examination, and determines the processes that formed them.
  • Hazcam
    Hazcam
    Hazcams are photographic cameras mounted on the front and rear of NASA's Spirit and Opportunity rover missions to Mars....

    s, two B&W cameras with 120 degree field of view, that provide additional data about the rover's surroundings.


The rover arm holds the following instruments:
  • Mössbauer spectrometer (MB) MIMOS II
    MIMOS II
    MIMOS II is the miniaturised Mössbauer spectrometer, developed by Dr. Göstar Klingelhöfer at the Johannes Gutenberg University in Mainz, Germany, that is used on the Mars Exploration Rovers Spirit and Opportunity for close-up investigations on the Martian surface of the mineralogy of iron-bearing...

     – used for close-up investigations of the mineralogy of iron-bearing rocks and soils.
  • Alpha particle X-ray spectrometer (APXS) – close-up analysis of the abundances of elements that make up rocks and soils.
  • Magnets – for collecting magnetic dust particles
  • Microscopic Imager (MI) – obtains close-up, high-resolution images of rocks and soils.
  • Rock Abrasion Tool
    Rock Abrasion Tool
    The Rock Abrasion Tool is a grinding and brushing installation on NASA’s twin Mars Exploration Rovers, Spirit and Opportunity , which landed on Mars in January 2004...

     (RAT) – exposes fresh material for examination by instruments on-board.


The cameras produce 1024-pixel by 1024-pixel images, the data is compressed with ICER
ICER
ICER is a wavelet-based image compression file format used by the NASA Mars Rovers. ICER has both lossy and lossless compression modes.The Mars Exploration Rovers “Spirit” and “Opportunity” both use ICER...

, stored, and transmitted later.

The rover's name was chosen through a NASA sponsored student essay competition.

Mission overview



The primary surface mission for Opportunity was planned to last 90 sols
Timekeeping on Mars
Various schemes have been used or proposed to keep track of time and date on the planet Mars independently of Earth time and calendars.Mars has an axial tilt and a rotation period similar to those of Earth. Thus it experiences seasons of spring, summer, autumn and winter much like Earth, and its...

. The mission has received several extensions and has been operating for days since landing. An archive of weekly updates on the rover's status can be found at the
Opportunity Update Archive.

From its initial landing, by chance, into an impact crater
Eagle (crater)
Eagle is a 22-metre impact crater located on Mars on Meridiani Planum. The Opportunity rover came to rest inside Eagle crater when it landed in 2004...

 amidst an otherwise generally flat plain,
Opportunity has successfully investigated soil and rock samples and taken panoramic photos of its landing site. Its sampling allowed NASA scientists to make hypotheses concerning the presence of hematite
Hematite
Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 and past presence of water on the surface of Mars. Following this, it was directed to travel across the surface of Mars to investigate another crater site, Endurance crater
Endurance (crater)
Endurance is an impact crater on Mars that was visited by the Opportunity rover from May until December 2004. Mission scientists named the crater after the ship Endurance that sailed to the Antarctic in an exploration voyage organized by Ernest Shackleton.The rover entered the crater interior on...

, which it investigated from June – December 2004. Subsequently, Opportunity examined the impact site of its own heat shield
Heat shield
A heat shield is designed to shield a substance from absorbing excessive heat from an outside source by either dissipating, reflecting or simply absorbing the heat...

 and discovered an intact meteorite
Meteorite
A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. Meteorites can be big or small. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...

, now known as Heat Shield Rock
Heat Shield Rock
Heat Shield Rock is a basketball-sized iron-nickel meteorite found on Mars by the Mars rover Opportunity in January 2005. The meteorite was formally named Meridiani Planum meteorite by the Meteoritical Society in October, 2005 .-Discovery:Opportunity encountered the meteorite entirely by chance,...

, on the surface of Mars.

From late April 2005 to early June of that year,
Opportunity was perilously lodged in a sand dune, with several wheels buried in the sand. Over a six week period Earth-based physical simulations were performed to decide how best to extract the rover from its position without risking a permanent immobilization of the valuable vehicle. Successful maneuvering a few centimeters at a time eventually freed the rover, which resumed its travels.

Opportunity was directed to proceed in a southerly direction to Erebus crater
Erebus (crater)
Erebus is a crater on Mars visited by the Opportunity rover on the way to the much larger crater Victoria. It is named after the polar exploration vessel HMS Erebus...

, a large, shallow, partially buried crater and a stopover on the way south towards Victoria crater
Victoria (crater)
Victoria is an impact crater on Mars located at 2.05°S, 5.50°W in Meridiani Planum, visited by the Mars Exploration Rover Opportunity. It is roughly 730 metres wide, nearly eight times the size of the crater Endurance, visited by Opportunity from sols 951 to 1630...

, between October 2005 and March 2006. It experienced some mechanical problems with its robotic arm.

In late September 2006,
Opportunity reached Victoria crater and explored along the rim in a clockwise direction. In June 2007 it returned to Duck Bay, its original arrival point; in September 2007 it entered the crater to begin a detailed study. In August 2008, Opportunity left Victoria crater for Endeavour crater
Endeavour (crater)
Endeavour is an impact crater located in Meridiani Planum on Mars. Endeavour is 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...

, which it reached on 9 August 2011.

Opportunity's total odometry as of November 16, 2011 (sol 2777) is 34328.09 metres (21.33 mi).


Landing site: "Eagle" crater





Opportunity landed in Meridiani Planum
Meridiani Planum
Meridiani Planum is a plain located 2 degrees south of Mars' equator , in the westernmost portion of Terra Meridiani. It hosts a rare occurrence of gray crystalline hematite...

 at 1.95°S 354.47°E, about 25 km downrange (east) of its intended target. Although Meridiani is a flat plain
Plain
In geography, a plain is land with relatively low relief, that is flat or gently rolling. Prairies and steppes are types of plains, and the archetype for a plain is often thought of as a grassland, but plains in their natural state may also be covered in shrublands, woodland and forest, or...

, without the rock fields seen at previous Mars landing sites,
Opportunity rolled into an impact crater
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 22 meters in diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...

, with the rim of the crater approximately 10 meters (32 ft) from the rover. NASA Scientists were so excited about landing in a crater that they called the landing a "hole in one
Golf glossary
The following is a glossary of the terminology used in the sport of golf. Where words in a sentence are also defined elsewhere in this article, they appear in italics.- A :The following is a glossary of the terminology used in the sport of golf...

"; however, they were not aiming for the crater (or even knew it existed). Later, the crater was named
Eagle crater and the landing site designated "Challenger
Space Shuttle Challenger disaster
The Space Shuttle Challenger disaster occurred on January 28, 1986, when Space Shuttle Challenger broke apart 73 seconds into its flight, leading to the deaths of its seven crew members. The spacecraft disintegrated over the Atlantic Ocean, off the coast of central Florida at 11:38 am EST...

 Memorial Station". This was the darkest landing site ever visited by a spacecraft on Mars. It would be two weeks before
Opportunity was able to get a better look at its surroundings.

Scientists were intrigued by the abundance of rock outcrops dispersed throughout the crater, as well as the crater's soil, which appeared to be a mixture
Mixture
In chemistry, a mixture is a material system made up by two or more different substances which are mixed together but are not combined chemically...

 of coarse gray grains and fine reddish grains. This sweeping look at the unusual rock outcropping near
Opportunity was captured by the rover's panoramic camera. Scientists believe the seemingly layered rocks are either volcanic ash deposits or sediments laid down by wind or water. It was given the name Opportunity Ledge.

Geologists said that the layers—some no thicker than a finger—indicate the rocks likely originated either from sediments carried by water or wind, or from falling volcanic ash. "We should be able to distinguish between those two hypotheses", said Dr. Andrew Knoll of Harvard University, Cambridge, a member of the science team for
Opportunity and its twin, Spirit. If the rocks are sedimentary, water is a more likely source than wind, he said.

These layered rocks measure only 10 centimeters (4 inches) tall and are thought to be either volcanic ash deposits or sediments carried by water or wind. The layers are very thin measuring just a few millimeters thick in some cases.
"Opportunity Ledge" outcroppings


On Sol 15, Opportunity took a close up of the rock "Stone Mountain" in the outcrop area of the crater, raising speculation that the rock consisted of very fine grain or dust, in contrast to Earth sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

, which is compacted sand with rather large grains. The weathering
Weathering
Weathering is the breaking down of rocks, soils and minerals as well as artificial materials through contact with the Earth's atmosphere, biota and waters...

 agent eroding
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 away layers of this rock seemed to be visible as dark spots.

A picture received on 10 February (taken on Sol 16) showed that the thin layers in the bedrock converge and diverge at low angles, suggesting that some "moving current" such as volcanic flow, wind, or water formed these rocks. The discovery of these layers was significant for scientists who had planned this mission to test the "water hypothesis" rigorously.
El Capitan outcropping

On 19 February the survey of "Opportunity Ledge" was declared successful. A specific target in the outcrop (dubbed "
El Capitan"), whose upper and lower portions appeared to differ in layering and weathering characteristics, was selected for further investigation. El Capitan, about 10 centimeters (4 inches) high, was named after a mountain in Texas. Opportunity reached "El Capitan" on Sol 27, and took a first picture of the rocks with its panoramic camera.

On Sol 30,
Opportunity used its Rock Abrasion Tool
Rock Abrasion Tool
The Rock Abrasion Tool is a grinding and brushing installation on NASA’s twin Mars Exploration Rovers, Spirit and Opportunity , which landed on Mars in January 2004...

 (RAT) for the first time to investigate the rocks around
El Capitan. The image on the right-hand side shows a close up view taken after the drilling and cleaning process was complete. Due to chance, two spherules
Martian spherules
Martian spherules are the abundant spherical hematite inclusions discovered by the Mars rover Opportunity at Meridiani Planum on the planet Mars...

 were also cut partially, and seem to show scratches and other marks made by the diamond-crusted grind tool. The black areas are artifacts of the imaging process, when parts of the picture are missing.

During a press conference on 2 March 2004, mission scientists discussed their conclusions about the bedrock, and the evidence for the presence of liquid water during their formation. They presented the following reasoning to explain the small, elongated voids in the rock visible on the surface and after grinding into it (see last two images below).

These voids are consistent with features known to geologists as "vug
Vug
Vugs are small to medium-sized cavities inside rock that may be formed through a variety of processes. Most commonly cracks and fissures opened by tectonic activity are partially filled by quartz, calcite, and other secondary minerals. Open spaces within ancient collapse breccias are another...

s". These are formed when crystals form inside a rock matrix and are later removed through erosive processes, leaving behind voids. Some of the features in this picture are "disk-like", which is consistent with certain types of crystals, notably sulfate minerals.

Additionally, mission members presented first data from the MIMOS II
MIMOS II
MIMOS II is the miniaturised Mössbauer spectrometer, developed by Dr. Göstar Klingelhöfer at the Johannes Gutenberg University in Mainz, Germany, that is used on the Mars Exploration Rovers Spirit and Opportunity for close-up investigations on the Martian surface of the mineralogy of iron-bearing...

 Mössbauer spectrometer taken at the bedrock site. The iron spectrum obtained from the rock El Capitan shows strong evidence for the mineral jarosite
Jarosite
Jarosite is a basic hydrous sulfate of potassium and iron with a chemical formula of KFe3+362. This sulfate mineral is formed in ore deposits by the oxidation of iron sulfides...

. This mineral contains hydroxide
Hydroxide
Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and a hydrogen atom held together by a covalent bond, and carrying a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, as a ligand, a nucleophile, and a...

 ions, which indicates the presence of water when the minerals were formed. Mini-TES data from the same rock showed that it consists of a considerable amount of sulfates.


Opportunity digs a trench


The rover alternately pushed soil forward and backward out of the trench with its right front wheel while other wheels held the rover in place. The rover turned slightly between bouts of digging to widen the hole. "We took a patient, gentle approach to digging", Biesiadecki said. The process lasted 22 minutes.

The resulting trench—the first dug by either Mars Exploration Rover—is about 50 centimeters (20 inches) long and 10 centimeters (4 inches) deep. "It came out deeper than I expected", said Dr. Rob Sullivan of Cornell University, Ithaca, N.Y., a science-team member who worked closely with engineers to plan the digging.

Two features that caught scientists' attention were the clotty texture of soil in the upper wall of the trench and the brightness of soil on the trench floor, Sullivan said.

By inspecting the sides and floor of a hole it dug, Opportunity found some things it did not see beforehand, including round pebbles that are shiny and soil so fine-grained that the rover's microscope cannot make out individual particles.

"What's underneath is different than what's at the immediate surface", said Dr. Albert Yen, rover science team member at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Initial scientific results from the Opportunity rover were published in the journal Science


Endurance crater



On 30 April 2004, Sol 95,
Opportunity reached Endurance crater, which was known to have many layers of rocks. In May the rover circumnavigated the crater, and made observations with Mini-TES and the panoramic camera. The rock "Lion Stone" was investigated on Sol 107 and found to be similar in composition to the layers found in Eagle crater.

On 4 June 2004 mission members announced their intention to drive
Opportunity into Endurance, even if it should turn out to be impossible to get back out, targeting the various rock layers that were identified in the pictures from the crater rim. "This is a crucial and careful decision for the Mars Exploration Rovers' extended mission", said Dr. Edward Weiler, NASA's associate administrator for space science. Dr Squyres, principal investigator from Cornell University said: "Answering the question of what came before the evaporites is the most significant scientific issue we can address with Opportunity at this time."

A first drive into the crater was executed on 8 June, Sol 133, and
Opportunity backed out again the same day.
It was found that the angle of the surface was well inside the safety margin (about 18 degrees), and the full excursion towards the rock layer of interest was started. During Sols 134 (12 June), 135, and 137 the rover drove deeper and deeper into the crater. Although some wheel slip was observed, driving was discovered to be possible even at slope angles up to 30 degrees.

Wispy clouds, similar to Earth's cirrus cloud
Cirrus cloud
Cirrus clouds are atmospheric clouds generally characterized by thin, wispy strands, giving them their name from the Latin word cirrus meaning a ringlet or curling lock of hair...

s, were spotted.

Opportunity spent roughly 180 sols inside the crater, before backing out of it again in mid December 2004, on Sol 315. Scientific results of the sedimentary geology of the crater were published in the journal Earth and Planetary Science Letters
Earth and Planetary Science Letters
The journal has a 2009 impact factor of 4.062, ranking third in the category "Geophysics & Geochemisry"....





Heat Shield Rock


After exiting Endurance crater, in January 2005
Opportunity went to examine its own discarded heat shield
Heat shield
A heat shield is designed to shield a substance from absorbing excessive heat from an outside source by either dissipating, reflecting or simply absorbing the heat...

. While in the vicinity of the heat shield, on Sol 345 it happened to come upon an object which was immediately suspected and soon confirmed to be a meteorite
Meteorite
A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. Meteorites can be big or small. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...

. The meteorite was promptly named Heat Shield Rock, and is the first meteorite identified on another planet (although the Bench Crater
Bench Crater meteorite
The Bench Crater meteorite is a meteorite discovered on the Moon in 1969. It was the first meteorite to be discovered on a solar system body other than the Earth. It is listed as a carbonaceous chondrite by the Meteoritical Society.-References:...

 and Hadley Rille
Hadley Rille meteorite
The Hadley Rille meteorite was a meteorite discovered on the Moon at coordinates 26° 26' 0" N, 3° 39' 20" E, during the Apollo 15 mission in 1971. It was the second meteorite to be discovered on a solar system body other than the Earth...

 meteorites were found earlier on the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

).

After about 25 sols of observations Opportunity headed south for a crater named Argo
Argo (crater)
Argo is a crater located in the Meridiani Planum, on Mars, that was visited by the Opportunity rover approximately on its 365th Martian sol. The crater is located approximately south of the heat shield and Heat Shield Rock.-External links:*...

, nearly 300 m from the heat shield.


Southern transit


The rover was commanded to dig another trench on the vast plains of Meridiani Planum, on Sol 366, and observations continued until Sol 373 (10 February 2005). The rover then passed the craters "Alvin
Alvin (crater)
Alvin is a small crater on Mars. It was visited by the Opportunity rover in 2005.-External links:*...

" and "Jason", and by Sol 387, approached a "crater triplet" on its way to Vostok
Vostok (crater)
Vostok is a crater on Mars that was reached by the rover Opportunity on sol 399 . Vostok is located roughly 1200 meters south of Endurance in Meridiani Planum...

 Crater. Along the way, Opportunity set a distance record for one-day travel by either rover: 177.5 meters (582 ft), on 19 February 2005. On Sol 389 (26 February 2005), the rover approached one of the three craters, dubbed Naturaliste
Naturaliste (crater)
Naturaliste is the name of a crater on Mars. It was visited by the Opportunity rover in 2005.-External links:*...

. A rock target named "Normandy" was chosen for investigation on Sol 392, and
Opportunity remained there until Sol 395.

Opportunity reached Vostok Crater on Sol 399, finding it mostly filled with sand and lined by outcrops. It was then ordered south into what has been called "etched terrain", to search for more bedrock.


On 20 March 2005 (Sol 410) Opportunity set a new Martian record for the longest single day drive when it drove 220 meters (722 feet).

By Sol 415,
Opportunity stopped by some soil ripples
Ripple marks
In geology, ripple marks are sedimentary structures and indicate agitation by water or wind.- Defining ripple cross-laminae and asymmetric ripples :...

 to investigate the differences between soil in the trough of a ripple and its crest. Various soil targets included "Mobarak" in the trough, named in honor of Persian New Year, and "Norooz" and "Mayberooz" on the crest. By Sol 421, the rover left the ripple for "Viking" crater.

Stuck in sand



Between 26 April 2005 (Sol 446) and 4 June 2005 (Sol 484) Opportunity was stuck in a Martian sand dune.

The problem began on 26 April 2005 (Sol 446) when
Opportunity inadvertently dug itself into a sand dune: Mission scientists reported that images indicated all four corner wheels were dug in by more than a wheel radius, just as the rover attempted to climb over a dune about 30 centimeters (12 inches) tall. The sand dune was designated "Purgatory Dune" by mission planners.

The rover's condition was simulated on Earth prior to any attempt to move, out of concern that the rover might become permanently immobilized. After various simulations intended to mimic the properties and behavior of Martian sand were completed, the rover executed its first wheel movements on 13 May 2005 (Sol 463), intentionally advancing only a few centimeters, after which mission members evaluated the results.

During Sol 465 and 466 more drive commands were executed, and with each trial the rover moved another couple of centimeters. At the end of each movement, panoramic images were acquired to investigate the atmosphere and the surrounding dune field. The sand dune escape maneuver was successfully completed on 4 June 2005 (Sol 484), and all six wheels of Opportunity were on firmer ground. After studying "Purgatory" from Sol 498 to Sol 510, Opportunity proceeded southwards towards "Erebus crater".

Erebus crater


Opportunity studied Erebus crater
Erebus (crater)
Erebus is a crater on Mars visited by the Opportunity rover on the way to the much larger crater Victoria. It is named after the polar exploration vessel HMS Erebus...

, a large, shallow, partially buried crater and a stopover on the way south towards Victoria crater, between October 2005 and March 2006.

New programming to measure the percentage of slip in the wheels was successful in preventing the rover from getting stuck. Another "Purgatory"-like incident was averted on Sol 603, when onboard slip check software stopped a drive after slip reached 44.5%. It proceeded over many ripples
Ripple marks
In geology, ripple marks are sedimentary structures and indicate agitation by water or wind.- Defining ripple cross-laminae and asymmetric ripples :...

 and 'half-pipes', taking photographs after each sol's journey.

On Sol 628 (3 November 2005) Opportunity woke up in the midst of a mild dust storm that lasted three days. The rover was able to drive in self protective auto-mode during the storm but could not take any post-drive images. Less than three weeks later, another cleaning event
Cleaning event
A cleaning event is a phenomenon whereby dust is removed from solar panels, particularly ones on Mars, by the action of wind. The term cleaning event is used on several NASA webpages; generally the term is used in reference to the fact that Martian winds have blown dust clear of the solar panels of...

 cleared the dust off of the solar array so as to produce around 720 watt-hours (80% of max). On Sol 649 (1 December 2005), it was discovered the motor used to stow the robotic arm for travel was stalling. This problem took nearly two weeks to fix. Since then, the arm is stowed only for travel, and is extended at night to prevent the arm from getting stuck.


Opportunity observed numerous outcroppings around Erebus crater. It also collaborated with ESA
European Space Agency
The European Space Agency , established in 1975, is an intergovernmental organisation dedicated to the exploration of space, currently with 18 member states...

's Mars Express
Mars Express
Mars Express is a space exploration mission being conducted by the European Space Agency . The Mars Express mission is exploring the planet Mars, and is the first planetary mission attempted by the agency. "Express" originally referred to the speed and efficiency with which the spacecraft was...

 by using the miniature thermal
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...

 emission spectrometer
Spectrometer
A spectrometer is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. The variable measured is most often the light's intensity but could also, for instance, be the polarization...

 and panoramic camera (Pancam), and took images of a transit across the sun by Phobos. On Sol 760 (22 March 2006),
Opportunity began the journey to its next destination, "Victoria" crater, which it would reach in September 2006 (Sol 951). It would stay at "Victoria" crater until August 2008 (Sol 1630 – 1634).

Shoulder troubles


Opportunity's "shoulder" joint has had troubles since Sol 2 (25 Jan. 2004), the rover's second day on Mars. Engineers discovered that the heater on the shoulder azimuth joint, which controls side-to-side motion of the robotic arm, was stuck in the "on" position. Closer investigation revealed that the on-off switch had probably failed during assembly, test, and launch operations on Earth. Fortunately for Opportunity, the rover was equipped with a built-in safety mechanism called a "T-stat box" (thermostatic switch) that provided protection against overheating. When the shoulder azimuth joint, also known as Joint 1, got too hot, the T-stat switch automatically opened and temporarily disabled the heater. When the joint got cold again, the T-stat closed. As a result, the heater stayed on all night but not all day.

The safety mechanism worked until Opportunity approached the first winter on Mars. As the Sun began to retreat lower in the sky and solar power levels dropped, it became clear that Opportunity would not be able to keep the batteries charged with a heater draining power all night long. On Sol 122 (28 May 2004), rover operators began using a procedure known as "deep sleep," during which Opportunity disconnected the batteries at night. Deep sleep prevented the stuck heater (and everything else on the rover except the clock and the battery heaters) from drawing power. When the Sun came up the next morning and sunlight began hitting the solar arrays, the batteries automatically reconnected, the robotic arm became operational, the shoulder joint warmed up, and the thermostatic switch opened, disabling the heater. As a result, the shoulder joint was extremely hot during the day and extremely cold at night. Such huge temperature swings, which tend to make electric motors wear out faster, were taking place every sol.

This strategy worked for Opportunity until Sol 654 (25 Nov. 2005), when the Joint-1 azimuth motor stalled because of increased electrical resistance. Rover operators responded by delivering higher-than-normal current to the motor. This approach also worked, though Joint 1 continued to stall periodically. Typically, the rover's handlers simply tried again the next sol and the joint worked. They determined that the Joint-1 motor stalls were most likely due to damage caused by the extreme temperature cycles the joint experienced during deep sleep. As a precaution, they started keeping the robotic arm out in front of the rover overnight, rather than stowing it underneath the rover deck, where it would be virtually unusable in the event of a Joint-1 motor failure. They stowed the arm only while driving and unstowed it immediately at the end of each drive.

This strategy worked for Opportunity until Sol 1502 (15 April 2008), when the motor stalled at the beginning of an unstowing operation at the end of a drive, when the arm was still tucked underneath the rover. The motor continued to stall on all subsequent attempts, sol after sol. Engineers performed tests at various times of day to measure electrical resistance. They found that the resistance was lowest (essentially normal) when the joint was at its warmest—in the morning, following deep sleep, after the heater had been on for several hours, and just before the T-stat opened. They decided to try to unstow the arm one more time under these conditions.

At 08:30 Mars time on Sol 1531 (14 May 2008), they allowed Opportunity to direct as much current as possible to the warm, joint-1 azimuth motor in order to get the robotic arm into a usable position, in front of the rover. It worked.

Because Opportunity will likely never again stow the robotic arm, engineers devised a strategy for driving the rover safely with the arm deployed in front.

2006


On 22 March 2006 (Sol 760), Opportunity left Erebus crater and began the journey to "Victoria" crater, which it reached in September 2006 (Sol 951). It would stay at "Victoria" crater until August 2008 (Sol 1630 – 1634).

Victoria crater


Victoria crater
Victoria (crater)
Victoria is an impact crater on Mars located at 2.05°S, 5.50°W in Meridiani Planum, visited by the Mars Exploration Rover Opportunity. It is roughly 730 metres wide, nearly eight times the size of the crater Endurance, visited by Opportunity from sols 951 to 1630...

 is a massive impact crater approximately 7 kilometers from the original landing site. Victoria's diameter is six times larger than Endurance crater
Endurance (crater)
Endurance is an impact crater on Mars that was visited by the Opportunity rover from May until December 2004. Mission scientists named the crater after the ship Endurance that sailed to the Antarctic in an exploration voyage organized by Ernest Shackleton.The rover entered the crater interior on...

. Scientists believed that rock outcrops along the walls of Victoria would yield more information about the geologic history of Mars, if the rover survived long enough to investigate them.

On Sol 951 (26 September 2006) Opportunity reached the rim of Victoria Crater and transmitted the first substantial views of Victoria, including the dune field at the bottom of the crater. The Mars Reconnaissance Orbiter
Mars Reconnaissance Orbiter
Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

 photographed Opportunity at the rim of the crater.

Software upgrade


On 4 January 2007, both rovers received new flight software to the onboard computers. The update was received just in time for the third anniversary of their landing. The new systems let the rovers decide whether or not to transmit an image, and whether or not to extend their arms to examine rocks, which would save much time for scientists, as they would not have to sift through hundreds of images to find the one they want, or examine the surroundings to decide to extend the arms and examine the rocks.

Cleaning events


A series of cleaning event
Cleaning event
A cleaning event is a phenomenon whereby dust is removed from solar panels, particularly ones on Mars, by the action of wind. The term cleaning event is used on several NASA webpages; generally the term is used in reference to the fact that Martian winds have blown dust clear of the solar panels of...

s beginning on Sol 1151 (20 April 2007) have allowed Opportunity's solar energy production to rise to above 800 watt-hours per Sol. By Sol 1164 (4 May 2007) the solar array current was peaking above 4.0 amps
Ampere
The ampere , often shortened to amp, is the SI unit of electric current and is one of the seven SI base units. It is named after André-Marie Ampère , French mathematician and physicist, considered the father of electrodynamics...

, values not seen since Sol 18 (10 February 2004). However, the advent of extensive dust storms on Mars starting in mid 2007 (in-line with Mars' six Earth-year global dust storm cycle), dropped power levels to 280 watt-hours.

Dust storms


Towards the end of June, 2007, a series of dust storms began clouding the Martian atmosphere with dust. The storms intensified and by 20 July, both Opportunity and Spirit were facing the real possibility of system failure due to lack of power. NASA released a statement to the press which said (in part) "We're rooting for our rovers to survive these storms, but they were never designed for conditions this intense". The key problem caused by the dust storm was a dramatic reduction in solar power. There was so much dust in the atmosphere that it blocked 99 percent of direct sunlight to the rover. The Spirit rover, on the other side of the planet was getting slightly more sunlight than Opportunity.

Normally the solar arrays are able to generate about 700 watt-hours of energy per day. During the storms, the power generated was greatly reduced. If the rovers get less than 150 watt-hours per day they have to start draining their batteries. If the batteries run dry, key electrical elements are likely to fail due to the intense cold. On 18 July 2007, the rover's solar-panel only generated 128 watt-hours, the lowest level ever. NASA responded by commanding Opportunity to only communicate with Earth once every three days, the first time that this had happened since the start of the mission.

The dust storms continued through July and at the end of the month, NASA announced that the rovers, even under their very-low-power mode were barely getting enough energy to survive. If the temperature of the Opportunity's electronics module continued to drop, according to the announcement, "there is a real risk that Opportunity will trip a low-power fault. When a low-power fault is tripped, the rover's systems take the batteries off-line, putting the rover to sleep and then checking each sol to see if there is sufficient available energy to wake up and perform daily fault communications. If there is not sufficient energy, Opportunity will stay asleep. Depending on the weather conditions, Opportunity could stay asleep for days, weeks or even months, all the while trying to charge its batteries with whatever available sunlight there might be." It was quite possible that the rover would never wake up from a low-power fault.

By 7 August 2007 the storms appeared to be weakening, and although power levels were still low they were sufficient for Opportunity to begin taking and returning images. By 21 August dust levels were still improving, the batteries were fully charged and Opportunity was able to make its first drive since the dust storms began.

Duck Bay


Opportunity made a short drive into Duck Bay on 11 September 2007 and then reversed out again to test traction on the initial slope into Victoria Crater. On 13 September 2007 it returned
to begin a more thorough exploration of the inner slope, examining a series of layers of pale-coloured rock in the upper parts of Duck Bay and the face of the promontory Cape Verde
Cape Verde (Mars)
Cape Verde is a large promontory on the rim of Victoria Crater in Meridiani Planum, Mars. The Mars Exploration Rover Opportunity perched atop this feature to take a true color mosaic of the crater below...

 in detail.


Victoria crater exit


The rover exited Victoria crater on 24–28 August 2008 (sol 1630 – 1634) after experiencing a current spike similar to the one that preceded the malfunction of the right front wheel of its twin Spirit. It will now investigate sets of "dark cobbles" on the Meridiani plains on its planned journey to Endeavour crater.

Endeavour crater targeted


Endeavour
Endeavour (crater)
Endeavour is an impact crater located in Meridiani Planum on Mars. Endeavour is 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...

 is 22 kilometres (13.7 mi) in diameter and is 12 kilometers south-east of Victoria. Rover drivers estimated that this distance could be traversed in about two years. Scientists expect to see a much deeper stack of rock layers at the crater than those examined by Opportunity in Victoria. The discovery of phyllosilicate clay-bearing rock on the Endeavour crater rim promised exposure to a rock-type that is even more hospitable to life than types previously analyzed.

Solar conjunction



The solar conjunction
Solar conjunction
Solar conjunction occurs when a planet or other solar system object is on the opposite side of the sun from the Earth. From an Earth reference, the object will pass between the sun and the Earth. Communication with any spacecraft in solar conjunction will be severely limited due to the sun's...

, where the Sun is between Earth and Mars, started on 29 November 2008 and communication with the rovers was not possible until 13 December 2008. During this time the rover team planned to have Opportunity use the Moessbauer spectrometer to examine a rock outcrop named "Santorini".

2009


On 7 March 2009 (sol 1820)
Opportunity first saw the rim of Endeavour after driving about 3.2 kilometres (2 mi) since it left Victoria in August 2008. Opportunity also saw Iazu crater which is about 38 kilometres (23.6 mi) away and is about 7 kilometres (4.3 mi) in diameter.

On 7 April 2009 (sol 1850)
Opportunity generated 515 watt-hours after a cleaning event of the solar arrays increased energy production by about 40%. From 16 to 22 April (sol 1859 to 1865) Opportunity made a series of drives and during that week traveled a total distance of 478 metres (1,568.2 ft). The drive actuator for the right front wheel, which had been rested while Opportunity studied a rock outcrop called "Penrhyn", had motor currents very close to normal levels.

On 18 July 2009 (Sol 1950) a large dark rock was noted in the opposite direction from which Opportunity was travelling and so the rover headed towards it, reaching it on 28 July (Sol 1959). The rock turned out to be a meteorite and was named Block Island. Opportunity spent until 12 September 2009 (Sol 2004) investigating the meteorite, before returning to its journey towards Endeavour Crater.

Its journey was interrupted on Sol 2022 by the find of another meteorite, a 0.5 meter specimen dubbed 'Shelter Island', which the rover investigated until Sol 2034. It then headed for another meteorite, 'Mackinac Island', which it reached four sols later on Sol 2038 (17 October 2009). The rover conducted a drive-by imaging sequence but otherwise did not investigate this meteorite, resuming its journey to Endeavour.

On 10 November 2009 (Sol 2061) the rover reached a rock target of interest, named 'Marquette Island'. Prolonged study until 12 January 2010 (Sol 2122) ensued as it was uncertain what type of rock this represented, but the eventual conclusion was that it was rock ejecta from deep within the surface of Mars rather than a meteorite.


2010



On 28 January 2010 (Sol 2138) Opportunity arrived at Concepcion crater. Opportunity successfully circumnavigated the 10-meter diameter crater before continuing on towards Endeavour. Energy production varied from about 305 watt-hours to about 270 Wh during this period.

On 5 May 2010, due to potentially hazardous dune fields along the direct path between Victoria and Endeavour, a new route was charted that extended the distance to travel between the two craters to 19 kilometers.

On 19 May 2010, Opportunity reached 2246 sols of operation, making it the longest Mars surface mission in history, breaking the record of 2245 sols set by Viking 1
Viking 1
Viking 1 was the first of two spacecraft sent to Mars as part of NASA's Viking program. It was the first spacecraft to successfully land on Mars and perform its mission, and until May 19, 2010 held the record for the second longest Mars surface mission of 6 years and 116 days .- Mission :Following...

.

In July 2010, it was announced that the Opportunity team is using the theme of names given to places visited
by British Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 Captain, Lieutenant James Cook
James Cook
Captain James Cook, FRS, RN was a British explorer, navigator and cartographer who ultimately rose to the rank of captain in the Royal Navy...

, in his 1769–1771 Pacific Ocean voyage in command of HMS Endeavour
HMS Endeavour
HMS Endeavour may refer to one of the following ships:In the Royal Navy:, a 36-gun ship purchased in 1652 and sold in 1656, a 4-gun bomb vessel purchased in 1694 and sold in 1696, a fire ship purchased in 1694 and sold in 1696, a storeship hoy purchased in 1694 and sold in 1705, a storeship...

, for informal names of sites at Endeavour Crater
Endeavour (crater)
Endeavour is an impact crater located in Meridiani Planum on Mars. Endeavour is 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...

. These currently include "Cape Tribulation" and "Cape Dromedary
Mount Gulaga
Mount Gulaga is one of the highest mountains on the south coast of New South Wales, Australia. It rises above the village of Central Tilba and is within the Gulaga National Park...

", "Cape Byron
Cape Byron
Cape Byron is the easternmost point of the mainland of Australia. It is located about northeast of the town of Byron Bay and projects into the Pacific Ocean...

" (the most easterly point of the Australian mainland), and "Point Hicks
Point Hicks
Point Hicks, formerly called Cape Everard, is a coastal headland on the eastern coast of Victoria, Australia, located within the Croajingolong National Park.- Name :...

" (the part of the Australian mainland first sighted by the Endeavour in 1770.)
On 8 September 2010, it was announced that Opportunity had reached the halfway point of the 19-kilometer journey between Victoria crater and Endeavour crater.

In November the rover spent a few days imaging a 20 meter crater called Intrepid while navigating through a field of small impact craters. On 14 November 2010 (Sol 2420) total odometry passed the 25 kilometer mark. Average solar array energy production in October and November was about 600 watt-hours.

Santa Maria crater


On 15 December 2010 (Sol 2450) the rover arrived at Santa Maria
Santa Maria (crater)
Santa Maria is an impact crater on Mars located at 2.172°S, 5.445°W in Meridiani Planum, visited by the Mars Exploration Rover Opportunity. It sits north west of the much larger Endeavour crater. It is about 80-90 meters across.-Exploration:...

 and spent several weeks investigating the 90 meter (300-foot) wide crater. The results from Opportunity were compared to data taken from orbit by the CRISM
CRISM
The Compact Reconnaissance Imaging Spectrometer for Mars is a visible-infrared spectrometer aboard the Mars Reconnaissance Orbiter searching for mineralogic indications of past water on Mars. The CRISM instrument team comprises scientists from over ten universities and led by principal...

 instrument, a spectrometer, on the Mars Reconnaissance Orbiter
Mars Reconnaissance Orbiter
Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...

. CRISM had detected water-bearing minerals at Santa Maria crater, and the rover helped further analyze this. Oppy drove farther in that Martian year (about 2 Earth years), then in any previous year.

2011


After its arrival at the edge of Santa Maria crater, the team positioned the rover at its southeastern rim and collected data. They also prepared for the two-week solar conjunction
Solar conjunction
Solar conjunction occurs when a planet or other solar system object is on the opposite side of the sun from the Earth. From an Earth reference, the object will pass between the sun and the Earth. Communication with any spacecraft in solar conjunction will be severely limited due to the sun's...

 of late January, when the Sun was between Earth and Mars and communication was blocked. In late March Opportunity began the 6.5 km journey between Santa Maria and Endeavour, and on 1 June, the rover passed the 30 km traverse milestone (over 50 times its designed distance). A fortnight later, on 17 July 2011 (sol 2,658), Opportunity had driven 20 miles on Mars.

Endeavour crater


Opportunity arrived at Endeavour crater on 9 August 2011, at a landmark called Spirit Point named after its rover twin
Spirit rover
Spirit, MER-A , is a robotic rover on Mars, active from 2004 to 2010. It was one of two rovers of NASA's ongoing Mars Exploration Rover Mission. It landed successfully on Mars at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, Opportunity , landed on the other side of the planet...

, after traversing 13 miles from Victoria crater, over a three year period. Endeavour is 14 miles (22.5 km) wide and offers scientists new terrain to explore, including older rocks than encountered heretofore, and clay minerals that may have formed in the presence of water. The rover's deputy principal investigator, Ray Arvidson, said it will probably not enter Endeavour crater as it appears to contain material observed previously. The rocks on the rim are older than any previously studied by Opportunity. "I think there's much more interest in driving around the perimeter of the rim," said Arvidson.

Upon arriving at Endeavour, Opportunity almost immediately began discovering Martian phenomena not previously observed. On Sol 2694 (22 August 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. "It has a composition similar to some volcanic rocks, but there's much more zinc and bromine than we've typically seen. We are getting confirmation that reaching Endeavour really has given us the equivalent of a second landing site for Opportunity."

Scientific findings


Opportunity has provided substantial evidence in support of the mission's primary scientific goals: to search for and characterize a wide range of rocks
Rock (geology)
In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

 and soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

s that hold clues to past water activity on Mars. In addition to investigating the "water hypothesis",
Opportunity has also obtained astronomical observations and atmospheric data.

Honors


Honoring
Opportunitys great contribution to the exploration of Mars, the asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

 39382 has been named Opportunity
39382 Opportunity
Asteroid 39382 Opportunity was discovered on September 24, 1960, by Ingrid van Houten-Groeneveld, Cornelis Johannes van Houten and Tom Gehrels. The asteroid was spotted by examining photographic plates taken by telescopes at the Palomar Observatory....

. The name was proposed by Ingrid van Houten-Groeneveld
Ingrid van Houten-Groeneveld
Ingrid van Houten-Groeneveld is a Dutch astronomer.In a jointly-credited trio with Tom Gehrels and her husband Cornelis Johannes van Houten, she was an extremely prolific discoverer of many thousands of asteroids...

 who along with Cornelis Johannes van Houten
Cornelis Johannes van Houten
Cornelis Johannes van Houten was a Dutch astronomer, sometimes referred to as Kees van Houten.Born in The Hague, he spent his entire career at Leiden University except for a brief period as research assistant at Yerkes Observatory...

 and Tom Gehrels
Tom Gehrels
Tom Gehrels , was an American astronomer, Professor Planetary Sciences, and Astronomer at the University of Arizona, Tucson....

 discovered the asteroid on 24 September 1960. Opportunity's lander is Challenger Memorial Station.

See also


  • Autonomous robot
    Autonomous robot
    Autonomous robots are robots that can perform desired tasks in unstructured environments without continuous human guidance. Many kinds of robots have some degree of autonomy. Different robots can be autonomous in different ways...

  • Comparison of embedded computer systems on board the Mars rovers
    Comparison of embedded computer systems on board the Mars rovers
    The embedded computer systems that are on board the various Mars rovers sent to Mars by NASA have to withstand the high radiation levels and large temperature changes in space and for this reason their computational resources are limited compared to current computer systems commonly used on...

  • Exploration of Mars
    Exploration of Mars
    The exploration of Mars has been an important part of the space exploration programs of the Soviet Union, the United States, Europe, and Japan. Dozens of robotic spacecraft, including orbiters, landers, and rovers, have been launched toward Mars since the 1960s...

  • Space exploration
    Space exploration
    Space exploration is the use of space technology to explore outer space. Physical exploration of space is conducted both by human spaceflights and by robotic spacecraft....

  • Spirit rover (MER-A)
    Spirit rover
    Spirit, MER-A , is a robotic rover on Mars, active from 2004 to 2010. It was one of two rovers of NASA's ongoing Mars Exploration Rover Mission. It landed successfully on Mars at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, Opportunity , landed on the other side of the planet...

  • Unmanned space missions
  • Curiosity rover

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