Alvin

Mission timeline

2004

Opportunity landed in Meridiani Planum at 1.95°S 354.47°E / -1.95; 354.47, about 25 kilometers (16 mi) downrange (east) of its intended target on January 25, 2004, at 05:05. Although Meridiani is a flat plain, without the rock fields seen at previous Mars landing sites, Opportunity rolled into an impact crater 22 meters in diameter, with the rim of the crater approximately 10 meters (33 ft) from the rover. NASA Scientists were so excited about landing in a crater that they called the landing a "hole in one"; however, they were not aiming for the crater (and did not know it existed). Later, the crater was named Eagle crater and the landing site designated "Challenger 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 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 (3.9 in) 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.

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, which is compacted sand with rather large grains. The weathering agent eroding away layers of this rock seemed to be visible as dark spots.

2005

After exiting Endurance crater, in January 2005 Opportunity was driven to examine its own discarded heat shield. While in the vicinity of the heat shield, on Sol 345 it came upon an object that was immediately suspected and soon confirmed to be a meteorite. The meteorite was promptly named Heat Shield Rock, and is the first meteorite identified on another planet (although the Bench Crater and Hadley Rille meteorites were found earlier on the Moon).

After about 25 sols of observations Opportunity headed south for a crater named Argo, nearly 300 meters (980 ft) from the heat shield.

The rover was commanded to dig another trench on the vast plains of Meridiani Planum, on Sol 366, and observations continued until Sol 373 (February 10, 2005). The rover then passed the craters "Alvin" and "Jason", and by Sol 387, approached a "crater triplet" on its way to Vostok Crater. Along the way, Opportunity set a distance record for one-day travel by either rover: 177.5 meters (582 ft), on sol 381 February 19, 2005. On Sol 387 (February 26, 2005), the rover approached one of the three craters, dubbed Naturaliste. 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 March 20, 2005 (Sol 410) Opportunity set a new Martian record for the longest single day drive when it drove 220 meters (720 ft).

By Sol 415, Opportunity stopped by some soil 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.

Between April 26, 2005 (Sol 446) and June 4, 2005 (Sol 484) Opportunity was stuck in a Martian sand dune. The problem began on sol 445 (April 26, 2005) 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 in) tall. The sand dune was designated "Purgatory Dune" by mission planners.

2006

On March 22, 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 is a massive impact crater approximately 7 kilometers (4.3 mi) from the original landing site. Victoria's diameter is six times larger than Endurance crater. 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 949 (September 26, 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 photographed Opportunity at the rim of the crater.

2007

On January 4, 2007, both rovers received new flight software for their computers. The update was received just in time for the third anniversary of their landing. The new systems let the rovers decide whether to transmit an image, and whether 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.

The APXS instrument was now for the first time used to determine the amount of the noble gas argon in the atmosphere of Mars. The same measurements were done on the other side of the planet by its rover twin Spirit. The purpose of this experiment was to determine the atmospheric mixing processes and track their changes with time.

In January the rover drove along the north side of the crater rim and imaged the cliffs from different viewpoints. While driving another meteorite was found: Santa Caterina.

In March the Valley without peril was reached. This point had thought to be a possible entry point into the crater. But it turned out that this point had a too steep slope to drive carefully downside. After two additional cliffs where inspected it was decided to drive the whole way back to the point, where Opportunity arrived at Victoria crater. On June 15, 2007, the rover arrived at Duck Bay and prepared for entering the crater.

A series of cleaning events beginning on Sol 1149 (April 20, 2007) allowed Opportunity's solar energy production to rise to above 800 watt-hours per Sol. By Sol 1163 (May 4, 2007) the solar array current was peaking above 4.0 amperes, values not seen since Sol 16 (February 10, 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 energy production levels to 280 watt-hours per day.

Toward the end of June 2007, a series of dust storms began clouding the Martian atmosphere with dust. The storms intensified and by July 20, both Opportunity and Spirit were facing the real possibility of system failure due to lack of power. NASA released a statement to the press that 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.

2008

Rover daily power output averaged 580 watt-hours in the first days of 2008, with atmospheric opacity (tau) caused by dust at about 0.71, and solar array dust factor averaging 0.787.

On Sol 1502 (April 15, 2008) 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 local Mars time on Sol 1529 (May 14, 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.

The rover exited Victoria crater's Duck Bay on August 24–28, 2008 (sol 1630–1634). Before exiting the crater the rover experienced a current spike similar to the one that preceded the malfunction of the right front wheel of its twin Spirit. After Victoria crater and during its journey to Endeavour crater the rover investigated sets of "dark cobbles" on the Meridiani plains.

Endeavour is 22 km (14 mi) in diameter and is 12 kilometers (7.5 mi) south-east of Victoria. Rover drivers estimated that this distance could be traversed in about two years. Scientists expected 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.

The solar conjunction, where the Sun is between Earth and Mars, started on sol 1366 November 29, 2008 and communication with the rovers was not possible until December 13, 2008. During this time the rover team planned to have Opportunity use the Mössbauer spectrometer to examine a rock outcrop named "Santorini".

2009

On sol 1818 (March 7, 2009) Opportunity first saw the rim of Endeavour after driving about 3.2 km (2.0 mi) since it left Victoria in August 2008. Opportunity also saw Iazu crater that was about 38 kilometers (24 mi) away and is about 7 kilometers (4.3 mi) in diameter.

On sol 1848 (April 7, 2009) Opportunity generated 515 watt-hours after a cleaning event of the solar arrays increased energy production by about 40%. From April 16 to 22 (sol 1859 to 1865) Opportunity made a series of drives and during that week traveled a total distance of 478 meters (1,568 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 sol 1947 (July 18, 2009) a large dark rock was noted in the opposite direction from which Opportunity was traveling and so the rover headed toward it, reaching it on sol 1957 (July 28). The rock turned out to be a meteorite and was named Block Island. Opportunity spent until September 12, 2009 (Sol 2004) investigating the meteorite, before returning to its journey toward Endeavour Crater.

Its journey was interrupted on Sol 2022 by the find of another meteorite, a 0.5 meters (1.6 ft) 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 2036 (October 17, 2009). The rover conducted a drive-by imaging sequence but otherwise did not investigate this meteorite, resuming its journey to Endeavour.

On sol 2059 (November 10, 2009) the rover reached a rock target of interest, named 'Marquette Island'. Prolonged study until sol 2121 January 12, 2010 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 January 28, 2010 (Sol 2138) Opportunity arrived at Concepcion crater. Opportunity successfully circumnavigated the 10-meter (33 ft) diameter crater before continuing on towards Endeavour. Energy production varied from about 305 watt-hours to about 270 Wh during this period.

On sol 2231 (May 5, 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 (12 mi).

On (May 19, 2010), Opportunity reached 2244 sols of operation, making it the longest Mars surface mission in history, breaking the record of 2245 sols set by Viking 1.

In July 2010, it was announced that the Opportunity team would use the theme of names given to places visited

by British Royal Navy Captain, Lieutenant James Cook, in his 1769–1771 Pacific Ocean voyage in command of HMS Endeavour, for informal names of sites at Endeavour Crater. These would include "Cape Tribulation" and "Cape Dromedary", "Cape Byron" (the most easterly point of the Australian mainland), and "Point Hicks" (the part of the Australian mainland first sighted by the Endeavour in 1770).

On sol 2353 (September 8, 2010), the halfway point of the 19 kilometers (12 mi) journey between Victoria crater and Endeavour crater was reached.

In November the rover spent a few days imaging a 20 meters (66 ft) crater called Intrepid while navigating through a field of small impact craters. On sol 2419 November 14, 2010 total odometry passed the 25 kilometers (16 mi) mark. Average solar array energy production in October and November was about 600 watt-hours.

On sol 2449 (December 15, 2010) the rover arrived at Santa Maria and spent several weeks investigating the 90 meters (300 ft) wide crater. The results from Opportunity were compared to data taken from orbit by the CRISM instrument, a spectrometer, on the Mars Reconnaissance Orbiter. CRISM had detected water-bearing minerals at Santa Maria crater, and the rover helped further analyze this. Opportunity drove farther in that Martian year (that is about 2 Earth years), than 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 of late January, when the Sun was between Earth and Mars and communication was blocked. In late March Opportunity began the 6.5 kilometers (4.0 mi) journey between Santa Maria and Endeavour, and on June 1, the rover passed the 30 kilometers (19 mi) traverse milestone (over 50 times its designed distance). Two weeks later, on sol 2657 (July 17, 2011), Opportunity had driven 32 km (20 mi) on Mars.

By sol 2699 (August 29, 2011), Opportunity had continued to function effectively 30 times longer than its planned 90-sol mission, aided by solar cell cleaning events, and performed extensive geological analysis of Martian rocks and planetary surface features with its instruments.

Opportunity arrived at Endeavour crater on sol 2709 (August 9, 2011), at a landmark called Spirit Point named after its rover twin, after traversing 21 km (13 mi) from Victoria crater, over a three-year period. Endeavour is 23 km (14 mi) 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. The rover survived so long this goal was accomplished, and by 2016 it was decided to not only enter Endevaour crater but also explore, for the first time in history what is thought to be a water carved gully on Mars (update:2016).

Upon arriving at Endeavour, Opportunity almost immediately began discovering Martian phenomena not previously observed. 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. "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." (See also Cape York (Mars))

2012

In January 2012 the rover returned data from Greeley Haven, named after the geologist Ronald Greeley, while enduring its fifth Martian winter. It studied the Martian wind, which has been described as "the most active process on Mars today", and conducted a radio science experiment. By carefully measuring radio signals, wobbles in Martian rotation may show whether the planet has a solid or liquid interior. The winter worksite sits on the Cape York segment of the rim of Endeavour Crater. Opportunity reached the edge of this 23 km (14 mi) crater in August after three years of driving from smaller Victoria Crater, which it studied for two years.

On Sol 2852 (February 1, 2012) the energy production from the solar array was 270 watt-hours, with a Mars atmospheric opacity (Tau) of 0.679, a solar array dust factor of 0.469, with total odometry at 34.36 km (21.35 mi). By March (around Sol 2890), 'Amboy' rock was studied with the MIMOS II Mössbauer spectrometer and the Microscopic Imager, and the amount of Argon gas in the Martian air was measured. The Mars winter solstice passed on March 30, 2012 (Sol 2909) and on April 1 there was a small cleaning event. On Sol 2913 (April 3, 2012) solar array energy production was 321 watt-hours.

The mission of Mars rover Opportunity continued, and by May 1, 2012 (Sol 2940), energy production had increased to 365 watt-hours, with the solar array dust factor at 0.534. The team prepared the rover for movement and finished up collecting data on Amboy rock. 60 Doppler radio passes were completed over the winter.

On May 8, 2012 (Sol 2947), the rover moved 3.7 metres (12 ft). On that day the Solar energy production was 357 watt-hours with a solar array dust factor of 0.536. Opportunity had been stationary on Greeley Haven for 130 Sols (Mars' days), with a 15 degrees tilt to the North to help survive the winter; after the drive the northerly tilt decreased to 8 degrees. The drive marked the end of the geodynamics science experiment, which used radio Doppler measurements while the rover was stationary. By June 2012, it studied Mars dust and a nearby rock vein christened "Monte Cristo" as it headed North.

On July 2, 2012 Opportunity's 3000 Sols on Mars were celebrated.

By July 5, 2012, NASA published a new panorama (seen below) showing the surroundings of Opportunity at the Greeley Haven position at Cape York. Also, the other end of the Endeavour crater is seen in the right half of the scene, a crater that spans 22 kilometers (14 mi) in diameter. On July 12, 2012 (Sol 3010), solar arrays produced 523 watt-hours and 34,580 m (21.49 mi) was the total distance traveled from landing. That month, Mars Reconnaissance Orbiter spotted a dust storm and water ice clouds near the rover.

2013

Opportunity began the year at the edge of Endeavour Crater's Cape York, and the total distance travelled since landing on Mars was 35 km (22 mi). After completing work at Matijevic Hill the Opportunity rover headed south to the rim of Endeavour Crater. Next, the rover headed south across a gap in the rim to a place the researchers called Botany Bay, then up onto the next rim segment to the south. There are two hills to the south of it, one called Solander Point and farther south is Cape Tribulation. The current aim is for Opportunity to reach Solander Point before winter reaches the Martian southern hemisphere as the area has ground tilted to the north allowing the rover to stay active during the winter months. In addition Solander Point has a large geological stack for Opportunity to explore.

In April 2013, the rover passed through a three-week-long solar conjunction, when communication with Earth was blocked because of the Sun. The rover arm was positioned on a rock during that time so the APXS could collect data.

On May 16, 2013, NASA announced that Opportunity had driven further than any other NASA vehicle on a world other than Earth. After Opportunity's total odometry went over 35.744 kilometers (22.210 mi) it surpassed the total distance driven by the Apollo 17 Lunar Roving Vehicle. The record for longest distance driven by a vehicle on another world was as of 2013 held by the Lunokhod 2 lunar rover. Based on wheel rotations Lunokhod 2 was thought to have covered 37 kilometers (23 mi), but Russian scientists have revised that to an estimated distance of about 42 kilometers (26 mi) based on orbital images of the lunar surface.

On May 17, 2013, NASA announced that a preliminary analysis of one of the rock targets, named "Esperance", suggested that water in the past may have had a neutral pH. This was later confirmed in further studies, supporting the notion that ancient Mars was a "water-rich world with conditions amenable for life". As of June 20, 2013 (Sol 3344), Opportunity's total odometry was reported at 36.84 km (22.89 mi), while en route to 'Solander Point.' June 21, 2013 marked five Martian years on the 'red planet'. The project manager, noting the harsh conditions of the planet, has said each day is "a gift".

By early July 2013 Opportunity was approaching Solander Point, with daily drives ranging from dozens of meters (yards) to over a hundred. It arrived at its base in early August 2013, after investigating a curious terrain patch along the way. Solander could provide a northward facing slope to aid in sunlight collection, as the Martian winter was approaching (as the season changes, the angle of the Sun is shifting). On Sol 3390 (August 6, 2013) energy intake was 385 watt-hours, down from 395 on Sol 3384 (July 31, 2013), and 431 on Sol 3376 (July 23, 2013). In May 2013 it had been as high as 546 watt-hours. Other factors that impact collection include the atmospheric opacity (i.e. "Tau") and "solar array dust factor"—dust that collects on the panels. Although the rover cannot clean the dust off, such systems were considered for the rover during its development.

2014

Opportunity started off 2014 on the western ridge of Endeavour crater, providing elevated panoramas of the surrounding region. Research on data from Mars orbiters identified interesting minerals on the outcrop. Some communication and difficulties the previous month delayed investigating these rocks, but on the positive side, the wait, along with a cleaning event over January 1, allowed for more electrical power to be available. The rover is tilted towards the Sun to help it get more power, and it is expected that it can remain active during the Martian winter.

On January 17, NASA reported that a rock, named "Pinnacle Island", that was not in a rover image taken on Sol 3528, "mysteriously" appeared 13 days later in a similar image taken on Sol 3540. One possible explanation, presented by Steven Squyres, principal investigator of the Mars Exploration Rover Mission, was that the rover, in one of its turning motions, flicked the rock from a few meters away and into the new location.

In response, Rhawn Joseph published an article in the fringe journal Journal of Cosmology on January 17, 2014, and filed a writ of mandamus on January 27, 2014, in San Francisco Federal Court, stating that the object is a living entity and demanded that NASA re-examine the rock more closely. However, NASA already had examined the rock with the rover's microscope and analyzers, and confirmed it was a rock with a high sulphur, manganese, and magnesium content. According to Steven Squyres, "We have looked at it with our microscope. It is clearly a rock." On February 14, 2014, NASA released an image showing the location from where the "Pinnacle Island" rock was dislodged by the Opportunity rover.

On January 23, 2014, NASA celebrated the tenth anniversary (officially, January 25, 2014) of the rover's landing on Mars by sharing a self-portrait of the rover from above. They also reported on the latest discoveries of some Martian rocks and stated, "These rocks are older than any we examined earlier in the mission, and they reveal more favorable conditions for microbial life than any evidence previously examined by investigations with Opportunity."

On January 24, 2014, NASA reported that current studies on the planet Mars by the Curiosity and Opportunity rovers will now be searching for evidence of ancient life, including a biosphere based on autotrophic, chemotrophic and/or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable. The search for evidence of habitability, taphonomy (related to fossils), and organic carbon on the planet Mars is now a primary NASA objective.

2015

2015 was a year of superlative achievements for the MER-B mission, starting off with summiting Cape Tribulation in January 2015, which was the highest elevation achieved yet on its mission. Then in March 2016 it accomplished the distance of a classic marathon. Also in March 2016 it achieved the steepest slope traverse (32 degree) yet of its mission, surpassing the slope it took on at Burns Cliff in 2004. MER-B was trying to reach a target on Knudsen Ridge, on the south side of Marathon Valley, which meant attempting a steep grade which can cause wheel slippage. Another effect of this angle was that sand and dust that had collected on the rover flowed in streaks over the back of the rover, such was the incline.

In 2015 MER-B entered Marathon Valley and would study it until September 2016.

On March 23, 2015, NASA reported Opportunity's flash memory was successfully reformatted. After completing analysis of the flash memory issues, engineers concluded that some of the problems stemmed from a single memory bank, one of Opportunity's seven "banks" of onboard flash memory. A software upgrade was sent which allows the rover to bypass this bank, known as Bank 7. By February 2015, total odometry exceeded 42 kilometers. From July to September, the rover mostly operated using a RAM-only mode, to avoid ongoing flash memory issues. In September, a series of tests were performed to better understand the volatility of the device.

During the beginning of October 2015, Opportunity began its drive to north-tilted slopes in Marathon Valley of the west rim of Endeavour crater in preparation for the Martian winter. By November 2, after attempting to use the rover's flash memory, Opportunity again suffered an "amnesia" event. and the decision was made to switch back to use RAM on November 11 (Sol 4195).

2016

On January 3, 2016 (Sol 4246), Opportunity went through the winter solstice on Mars with already improved solar insolation, with the rover producing 449 watt-hours from its solar panels. On January 25, 2016, Opportunity had marked twelve years since landing on Mars and continued its scientific investigation of Marathon Valley.

On March 31, 2016, Opportunity captured an image of a dust devil inside Endeavour crater. Although the Spirit rover saw dust devils frequently, they have been less common in the area that Opportunity is exploring.

In June 2016, MER-B took a special panoramic image called the Sacagawea Panorama in honor of Sacagawea, the Lemhi Shoshone woman that helped the Lewis and Clark Expedition on their journey of exploration across America in 1804 to 1806. The image was taken of Marathon Valley at Endeavour Crater on the planet Mars.

On the right side of this image is "Knudsen Ridge", and beyond Marathon valley is the floor of Endeavor crater. In the distance is the rim of crater on the other side.

In September 2016, Opportunity departed from Marathon Valley which it traversed through over the previous Earth year. As it continued to explore the Western rim of Endeavor crater, it was directed out of Lewis and Clark gap in Marathon valley, and made its way towards Spirit mound. By early October 2016, the rover had reached Spirit mound by passing through Bitterroot valley, where it began to collect data on a science target.

Starting in October 2016, the three new mission goals include driving down into Endeavour Crater along what is thought to be a water-carved gully, compare the material on the plains to the interior of the crater, and to find pre-impact rocks (rocks that pre-date the impact that presumably formed Endeavour crater).

By October 4, 2016, the rover had traveled 26.99 miles (43.44 km), and generated 472 watt-hours of electricity. This date was mission time of Sol (Mars days) 4514.

The gully in the above annotated picture is a few hundred meters from the rover, and is the location of the suspected fluid-carved, possibly water, gullies that have never been investigated from the surface before. One of the MER-B goals is to drive down to this gully and examine it.

2017

On Sol 4623 (January 24, 2017 PST) the team celebrated 13 years operating Opportunity on the surface of Mars. By February 7, 2017 (Sol 4636) the rover had traveled 44 kilometers (27 miles) on the surface of Mars. Power collection from the Sun on that date was 414 watt-hours. The long-term goal at the time was a gully south of the rover on the Western rim of Endeavour crater. Science operations also continued including microscopic imaging of select rocks, APXS operation, and atmospheric argon gas measurements.

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. Some other names considered for this feature were Perseverance Gulch, Perseverance Ravine, and Perseverance Gorge. It is a valley network that runs downslope in the Cape Bryon section of Western rim of Endeavour crater.

The Martian winter reached its hardest time for the rover this year, with reduced sunlight and colder temperatures. One strategy the Rover team uses is to position the Rover on northward faced slopes to get more sunlight, and because the gully runs east–west, they were often able to use the southern edge of the gully channel of Perseverance Valley to tilt the rover this way. The Martian winter solstice was in November 2017, and it is the 8th one that MER-B has passed through.

Some energy production readings from 2017:

Rover arrives at the Gully (Perseverance Valley) and heads into it, taking measurements and pictures, but also had to survive the Mars winter (November Winter Solstice).

2018

In 2018 the rover continued to explore the area called Perseverance Valley, which is on the western rim of Endeavor Crater. The feature was previously called "Gully" and it was named by the rover team in early 2017. The rover reached Perseverance Valley (the gully) in 2017 and spent the rest of the year exploring this area. In 2018 this in-depth study continued.

The Valley may have a previously unknown type of rock. It is thought to be a fluid-carved channel, a spillway from the surrounding planes down to the crater floor. Among the candidates for what carved the channels are water, but also ice or wind currents. One of the ongoing questions is the idea of ancient water on Mars, and how it may have impacted the modern Mars environment. In the 2010s NASA has been on the hunt for ancient fossils left by tiny living organisms especially when they make large colonies, such as Stromatolites, which look like mushroom shaped rocks but are made by colonies of bacteria. The question of ancient bacteria on Mars was raised in the 1990s, when a scientist thought he had found microscopic bacterial fossils on a meteorite that came from Mars (see ALH84001) but was found on Earth. Future missions, such as Mars 2020, will carry more advanced chemical and geological detectors to Mars with them; some images taken by Opportunity have led to speculation about whether the images contain evidence of extraterrestrial life. One example, as reported by National Geographic, appears to show a cauliflower-shaped rock in an image taken by the Spirit rover in 2007, which, to some scientists, resembled fossils of microscopic stromatolites, which are ubiquitous on Earth, and represent the earliest widely accepted example of life in Earth's biosphere. Stromatolites, thought to be signs of some of the earliest life discovered on Earth, almost 4 billion years ago, are on Earth today. Another candidate are cynobacteria which are also determined to be among the oldest life on Earth. Because of the large impacts that eject matter into space Mars has exchanged material with over long time scales, leading some to suggest life could make the journey between Earth and Mars. Indeed, cynobacteria survived for almost two-years in space (Aboard ISS) and could still come alive again when put in life conditions after being in zero-g, zero-air, high radiation conditions common to outer space. On the colonization side, cyanobacteria like nostoc colonies that have been studied for terraforming are known to survive on Mars regolith simulant and lower pressures. Some the evidence for ancient water include the discovery of minerals that form in the presence of water, such as Jarosite, discovered by Opportunity at Eagle Crater in 2004. (see also Martian spherules)

Opportunity studied the rock target Jornada del Muerto in Perseverance Valley, using its surviving suite of instruments including the Microscopic Imager (MI), APXS, and the color cameras. At this time rocks from the Matijevic Formation have not been found, and the valley is proving to have some complicated natures One area being studied is how the dust flows through channel and makes deposits.

2019

On February 12, 2019, NASA announced it made its final attempt to contact the rover before declaring the rover dead.

Sol milestones

Sol 3,000 (July 2, 2012)

Sol 4,000 (April 26, 2015)

Sol 5,000 (February 16, 2018)

Sol 5,111 (June 10, 2018) – Contact lost.

Sol 5,352 (Feb 12, 2019) – Mission officially declared complete.

Solar array energy production

Examples

Examples of watt-hours per sol collected by the rover:

Craters, rocks, etc.

Some of the craters MER-B has investigated

Eagle crater, visited 2004, 72 feet (22 meters) across (diameter)

Endurance crater, 2004, 130 meters (430 feet) across

Burn's Cliff

Victoria crater, 2006–9, 800 meters (half a mile) across.

Cape Verde

Endeavour crater, since 2011, 22 km (14 mi)

Cape York

Solander Point, 2013

Cape Tribulation

Marathon Valley, 2015-2016

Perseverance Valley (aka the Gully), 2017-2018

Rocks

Some excitement from finding meteorites, new types of rock or signatures detected from orbit, and speculations on ancient alien fossils which as of yet lean towards geological processes.

Examples

Block Island

Bounce Rock

El Capitan

Heat Shield Rock (formally the Meridiani Planum meteorite)

Last Chance

Mackinac Island

Oileán Ruaidh

Shelter Island

Jelly Doughnut (aka Pinnacle Island)

Some other famous targets are the "blueberries" (2004) and "newberries", aka Kirkwood spheres (2012)

See also List of rocks on Mars#Opportunity and List of surface features of Mars imaged by Opportunity

Images

The rover could take pictures with its different cameras, but only the PanCam camera had the ability to photograph a scene with different color filters. The panorama views are usually built up from PanCam images. By February 3, 2018, Opportunity had returned 224,642 pictures.

Panoramas

A selection of panoramas from the mission:

Traverse maps

An example of a rover traverse map featuring a line showing path of the rover, and mission sols, which are Mars days counted from its landing and typical of Mars surface mission time reporting. Topographic lines and various feature names are also common.