Opportunity, also known asMER-B (Mars Exploration Rover – B) orMER-1, and nicknamedOppy, is aroboticrover that was active onMars from 2004 until 2018.[1]Opportunity was operational on Mars for 5111sols (14 years, 138 days on Earth). Launched on July 7, 2003, as part ofNASA'sMars Exploration Rover program, it landed inMeridiani Planum on January 25, 2004, three weeks after its twin,Spirit (MER-A), touched down on the other side of the planet.[9] With a planned 90-sol duration of activity (slightly less than 92.5 Earth days),Spirit functioned until it got stuck in 2009 and ceased communications in 2010, whileOpportunity was able to stay operational for 5111 sols after landing, maintaining its power and key systems through continual recharging of its batteries usingsolar power, and hibernating during events such as dust storms to save power. This careful operation allowedOpportunity to operate for 57 times its designed lifespan, exceeding the initial plan by 14 years, 47 days (in Earth time). By June 10, 2018, when it last contacted NASA,[10][11] the rover had traveled a distance of 45.16 kilometers (28.06 miles).[7]
Mission highlights included the initial 90-sol mission, findingmeteorites such asHeat Shield Rock (Meridiani Planum meteorite), and over two years of exploring and studyingVictoria crater. The rover survived moderate dust storms and in 2011 reachedEndeavour crater, which has been considered as a "second landing site".[12] TheOpportunity mission is considered one of NASA's most successful ventures.[13]
Due to theplanetary 2018 dust storm on Mars,Opportunity ceased communications on June 10 and enteredhibernation on June 12, 2018. It was hoped it would reboot once the weather cleared,[14] but it did not, suggesting either a catastrophic failure or that a layer of dust had covered its solar panels. NASA hoped to re-establish contact with the rover, citing a recurring windy period which was forecast for November 2018 to January 2019, that could potentially clean off its solar panels.[15] On February 13, 2019, NASA officials declared that theOpportunity mission was complete, after the spacecraft had failed to respond to over 1,000 signals sent since August 2018.[16]
Determine the distribution and composition of minerals, rocks, and soils surrounding the landing sites.
Determine whatgeologic processes 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 byMars Reconnaissance Orbiter (MRO) instruments. This will help determine the accuracy and effectiveness of various instruments that survey Martian geology from orbit.
Search for iron-containing minerals, and to identify and quantify relative amounts of specific mineral types that contain water or were formed in water, such as iron-bearing carbonates.
Characterize themineralogy and textures of rocks and soils to determine the processes that created them.
Search for geological clues to the environmental conditions that existed when liquid water was present.
Assess whether those environments were conducive to life.
Animation of Opportunity trajectory from July 9, 2003, to January 25, 2004 Sun· Earth· Mars· Opportunity
Opportunity andSpirit rovers were part of theMars Exploration Rover program in the long-termMars Exploration Program. The Mars Exploration Program's four principal goals were to determine if the potential for life exists on Mars (in particular, whether recoverable water may be found on Mars), to characterize the Mars climate and its geology, and then to prepare for a potential human mission to Mars. The Mars Exploration Rovers were to travel across the Martian surface and perform periodic geologic analyses to determine if water ever existed on Mars as well as the types of minerals available, as well as to corroborate data taken by theMars Reconnaissance Orbiter (MRO).[18] Both rovers were designed with an expected 90sols (92 Earth days) lifetime, but each lasted much longer than expected.Spirit's mission lasted 20 times longer than its expected lifetime, and its mission was declared ended on May 25, 2011, after it got stuck in soft sand and expended its power reserves trying to free itself.Opportunity lasted 55 times longer than its 90 sol planned lifetime, operating for 5498 days from landing to mission end. An archive of weekly updates on the rover's status can be found at theOpportunity Update Archive.[19]
Delta II Heavy (7925H-9.5) lifting off from pad 17-B carrying MER-B in 2003 withOpportunity rover
Spirit andOpportunity were launched a month apart, on June 10 and July 8, 2003, and both reached the Martian surface by January 2004.Opportunity's launch was managed byNASA's Launch Services Program. This was the first launch of theDelta II Heavy. The launch period went from June 25 to July 15, 2003. The first launch attempt occurred on June 28, 2003, but the spacecraft launched nine days later on July 7, 2003, due to delays for range safety and winds, then later to replace items on the rocket (insulation and a battery). Each day had two instantaneous launch opportunities. On the day of launch, the launch was delayed to the second opportunity (11:18 p.m. EDT) in order to fix a valve.[20]
Opportunity's landing site (denoted with a star)
On January 25, 2004 (GMT) (January 24, 2004, PST),[21] the airbag-protected landing craft settled onto the surface of Mars in the Eagle crater.
From its initial landing into animpact crater amidst an otherwise generally flat plain,Opportunity successfully investigated regolith and rock samples and took panoramic photos of its landing site. Its sampling allowed NASA scientists to make hypotheses concerning the presence ofhematite and past presence of water on the surface of Mars.[22] Following this, it was directed to travel across the surface of Mars to investigate another crater site,Endurance crater, which it explored from June to December 2004.[23] Subsequently,Opportunity examined the impact site of its ownheat shield and discovered an intactmeteorite, now known asHeat Shield Rock, on the surface of Mars.[24]
Opportunity was directed to proceed in a southerly direction toErebus crater, a large, shallow, partially buried crater and a stopover on the way south towardsVictoria crater, 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 at Victoria crater; in September 2007 it entered the crater to begin a detailed study. In August 2008,Opportunity left Victoria crater forEndeavour crater, which it reached on August 9, 2011.[25]
At the rim of the Endeavour crater, the rover moved around a geographic feature namedCape York. The Mars Reconnaissance Orbiter had detectedphyllosilicates there, and the rover analyzed the rocks with its instruments to check this sighting on the ground. This structure was analyzed in depth until summer 2013. In May 2013 the rover was heading south to a hill namedSolander Point.[citation needed]
Lifetime progress map with Washington, D.C. overlay for size and distance comparison
Opportunity's total odometry by June 10, 2018 (sol 5111), was 45.16 km (28.06 mi), while the dust factor was 10.8.[26] Since January 2013, the solar array dust factor (one of the determinants of solar power production) varied from a relatively dusty 0.467 on December 5, 2013 (sol 3507), to a relatively clean 0.964 on May 13, 2014 (sol 3662).[27]
In December 2014, NASA reported thatOpportunity was suffering from "amnesia" events in which the rover failed to write data, e.g.telemetry information, tonon-volatile memory. The hardware failure was believed to be due to an age-related fault in one of the rover's seven memory banks. As a result, NASA had aimed to force the rover's software to ignore the failed memory bank;[28] amnesia events continued to occur, however, which eventually resulted in vehicle resets.[clarification needed] In light of this, on Sol 4027 (May 23, 2015), the rover was configured to operate in RAM-only mode, completely avoiding the use of non-volatile memory for storage.[29]
Graph of atmospheric opacity andOpportunity's energy reserveOpportunity's first self-portrait on Mars (February 14–20, 2018 /sols 4998−5004)
In early June 2018, alarge planetary-scale dust storm developed, and within a few days the rover's solar panels were not generating enough power to maintain communications, with the last contact on June 10, 2018.[5] NASA stated that they did not expect to resume communication until after the storm subsided,[30] but the rover kept silent even after the storm ended in early October,[30] suggesting either a catastrophic failure or a layer of dust covering its solar panels.[31] The team remained hopeful that a windy period between November 2018 and January 2019 might clear the dust from its solar panels, as had happened before.[31] Wind was detected nearby on January 8, and on January 26 the mission team announced a plan to begin broadcasting a new set of commands to the rover in case its radio receiver failed.[32]
More than 835 recovery commands were transmitted since losing signal in June 2018 to the end of January 2019 with over 1000 recovery commands transmitted before February 13, 2019.[16][34][35] NASA officials held a press conference on February 13 to declare an official end to the mission. NASA associate administrator Thomas Zurbuchen said, "It is therefore that I am standing here with a deep sense of appreciation and gratitude that I declare theOpportunity mission is complete."[36] As NASA ended their attempts to contact the rover, the last data sent was the song "I'll Be Seeing You" performed byBillie Holiday.[37] Assets that had been needed to supportOpportunity were transitioned to support theCuriosity rover and the then-upcomingPerseverance rover.[36]
The final communication from the rover came on June 10, 2018 (sol 5111) from Perseverance Valley,[16] and indicated a solar array energy production of 22Watt-hours for the sol, and the highest atmospheric opacity (tau) ever measured on Mars: 10.8.[38]
Opportunity (and its twin,Spirit) are six-wheeled,solar-powered robots standing 1.5 meters (4.9 ft) high, 2.3 meters (7.5 ft) wide and 1.6 meters (5.2 ft) long and weighing 180 kilograms (400 lb). Six wheels on arocker-bogie system enabled mobility over rough terrain. Each wheel had its own motor. The vehicle was steered at front and rear and was designed to operate safely at tilts of up to 30 degrees. The maximum speed was 5 centimeters per second (2.0 in/s);[39] 0.18 kilometers per hour (0.11 mph), although the average speed was about 1 centimeter per second (0.39 in/s). BothSpirit andOpportunity have pieces of the fallenWorld Trade Center's metal on them that were "turned into shields to protect cables on the drilling mechanisms".[40][41]
Solar arrays generated about 140 watts for up to fourteen hours per sol, while rechargeablelithium ion batteries stored energy for use at night.Opportunity's onboard computer uses a 20 MHzRAD6000 CPU with 128 MB of DRAM and 3 MB of EEPROM.[42] The rover'soperating temperature ranges from −40 to +40 °C (−40 to 104 °F) andradioisotope heaters provide a base level of heating, assisted by electrical heaters when necessary.[43]
Communications depended on an omnidirectional low-gain antenna communicating at a low data rate and a steerable high-gain antenna, both in direct contact with theDeep Space Network on Earth. A low-gain antenna was also used to relay data to spacecraft orbiting Mars.[44][45]
The rover uses a combination of solar cells and a rechargeable chemical battery.[49] This class of rover has two rechargeablelithium batteries, each composed of 8 cells with 8amp-hour capacity.[50] At the start of the mission the solar panels could provide up to around 900 watt-hours (Wh) per day to recharge the battery and power system in one Sol, but this could vary due to a variety of factors.[49] InEagle crater the cells were producing about 840 Wh per day, but by Sol 319 in December 2004, it had dropped to 730 Wh per day.[51]
Like Earth, Mars has seasonal variations that reduce sunlight during winter. However, since the Martian year is longer than that of the Earth, the seasons fully rotate roughly once every 2 Earth years.[52] By 2016, MER-B had endured seven Martian winters, during which times power levels drop which can mean the rover avoids doing activities that use a lot of power.[52] During its first winter power levels dropped to under 300 Wh per day for two months, but some later winters were not as bad.[52]
Another factor that can reduce received power is dust in the atmosphere, especially dust storms.[53] Dust storms have occurred quite frequently when Mars is closest to the Sun.[53] Global dust storms in 2007 reduced power levels forOpportunity andSpirit so much they could only run for a few minutes each day.[53] Due to the2018 dust storms on Mars,Opportunity enteredhibernation mode on June 12,[54][55] but it remained silent after the storm subsided in early October.[30]
Heat Shield Rock turned out to be the first meteorite discovered on Mars.
Opportunity has provided substantial evidence in support of the mission's primary scientific goals: to search for and characterize a wide range ofrocks andregolith that hold clues to pastwater activity on Mars. In addition to investigating the water,Opportunity has also obtained astronomical observations and atmospheric data.[citation needed]
Following its launch,Opportunity wasanthropomorphized by its operators: the rover was called a "she," drawing fromnautical tradition, and given an affectionate nickname, "Oppy." One scientist, who worked withOpportunity for over a decade, attributed this to the rover's unexpectedly long lifespan, which he called a story of "an underdog beating the odds," and its "familiar, almost biologically inspired shape."[56] The media attention surroundingOpportunity's shutdown spread this usage to the general public.
With word on February 12, 2019, that NASA was likely to conclude theOpportunity mission, many media outlets and commentators issued statements praising the mission's success and stating their goodbyes to the rover. One journalist, Jacob Margolis, tweeted his translation of the last data transmission sent byOpportunity on June 10, 2018, as "My battery is low and it's getting dark." The phrase struck a chord with the public, inspiring a period of mourning, artwork, andtributes to the memory ofOpportunity.[57]
When the quote became widely reported, some news reports mistakenly asserted that the rover sent that exact message in English, resulting in NASA being inundated with additional questions. Margolis wrote a clarifying article on February 16, making it clear he had taken statements from NASA officials who were interpreting the data sent byOpportunity, both on the state of its low power and Mars's high atmospheric opacity, and rephrased them in a poetic manner, never to imply the rover had sent the specific words.[57][58]
On March 24, 2015, NASA celebratedOpportunity having traveled the distance of amarathon race, 42.195 km (26.219 mi). The rover covered the distance in 11 years and 2 months. The JPL technicians celebrated the occasion by running a race.[61] The location in Mars where the rover reached the distance was aptly named Marathon Valley.[62]
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.[64][65]
^Torbet, Georgina (January 26, 2019)."NASA makes last-ditch attempt to revive dormant Mars rover Opportunity".digitaltrends.com. Designtechnica Corporation. Archived fromthe original on July 10, 2023. RetrievedJanuary 27, 2019.Now NASA scientists are trying a last-ditch attempt to contact the rover based on three unlikely but possible scenarios: that the rover's primary X-band radio has failed, that both the primary and secondary X-band radios have failed, or that the rover's internal clock has become offset. The team is commanding the rover to switch to its backup X-band radio and to reset its clock to counteract these possibilities.
Missions are ordered by launch date. Sign† indicates failure en route or before intended mission data returned.‡ indicates use of the planet as agravity assist en route to another destination.
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
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