Opportunity (rover)

Source: Wikipedia, the free encyclopedia.

Opportunity
sols (92.5 days)
  • Actual: 5,352 sols (5,498 days)
  • (8 Mars years
    • , 15 Earth years)
    Spacecraft properties
    Dry mass185 kilograms (408 lb)
    PowerSolar panels: 140 W
    Start of mission
    Launch dateJuly 8, 2003, 03:18
    SLC-17B
    ContractorBoeing
    End of mission
    DeclaredFebruary 13, 2019[5]
    Last contactJune 10, 2018[5]
    Eagle, Meridiani Planum
    1°56′46″S 354°28′24″E / 1.9462°S 354.4734°E / -1.9462; 354.4734 (Opportunity rover)[6]
    Distance driven45.16 km (28.06 mi)[7]

    Opportunity mission patch, featuring Duck Dodgers (Daffy Duck)[8]
    ← Spirit
    MRO →
    NASA Mars rovers
    ← Spirit
    Curiosity →

    Opportunity, also known as MER-B (Mars Exploration Rover – B) or MER-1, is a

    sol duration of activity (slightly less than 92.5 Earth days), Spirit functioned until it got stuck in 2009 and ceased communications in 2010, while Opportunity was able to stay operational for 5111 sols after landing, maintaining its power and key systems through continual recharging of its batteries using solar power, and hibernating during events such as dust storms to save power. This careful operation allowed Opportunity 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, finding

    Endeavour crater, which has been considered as a "second landing site".[12] The Opportunity mission is considered one of NASA's most successful ventures.[13]

    Due to the

    hibernation 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 the Opportunity mission was complete, after the spacecraft had failed to respond to over 1,000 signals sent since August 2018.[16]

    Objectives

    The scientific objectives of the Mars Exploration Rover mission were to:[17]

    • Search for and characterize a variety of rocks and soils that hold clues to past
      hydrothermal activity
      .
    • Determine the distribution and composition of minerals, rocks, and soils surrounding the landing sites.
    • Determine what geologic 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 by Mars 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 the mineralogy 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.

    Mission timeline

    Main article: Timeline of Opportunity
    Animation of Opportunity trajectory from July 9, 2003, to January 25, 2004
       Sun ·    Earth ·    Mars ·    Opportunity

    Opportunity and Spirit rovers were part of the

    sols (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 the Opportunity Update Archive.[19]

    Launch and landing

    Delta II Heavy (7925H-9.5) lifting off from pad 17-B carrying MER-B in 2003 with Opportunity rover

    Spirit and Opportunity 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 by

    NASA's Launch Services Program. This was the first launch of the Delta 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 an

    Endurance crater, which it explored from June to December 2004.[23] Subsequently, Opportunity examined the impact site of its own heat shield and discovered an intact meteorite, now known as Heat Shield Rock, on the surface of Mars.[24]

    Opportunity was directed to proceed in a southerly direction to Erebus crater, a large, shallow, partially buried crater and a stopover on the way south towards Victoria 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 for Endeavour crater, which it reached on August 9, 2011.[25]

    At the rim of the Endeavour crater, the rover moved around a geographic feature named Cape York. The Mars Reconnaissance Orbiter had detected

    phyllosilicates 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 named Solander 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 that Opportunity was suffering from "amnesia" events in which the rover failed to write data, e.g. telemetry information, to non-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]

    End of mission

    Graph of atmospheric opacity and Opportunity's energy reserve
    sols
    4998−5004)

    In early June 2018, a large 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]

    On February 12, 2019,[33] past and present members of the mission team gathered in the Jet Propulsion Laboratory (JPL)'s Space Flight Operations Facility to watch final commands being transmitted to Opportunity via the 70-meter (230-foot) dish of the Goldstone Deep Space Communications Complex in California. Following 25 minutes of transmission of the final 4 sets of commands, communication attempts with the rover were handed off to Canberra, Australia.[citation needed]

    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 the Opportunity 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 by Billie Holiday.[37] Assets that had been needed to support Opportunity were transitioned to support the Mars rovers Curiosity and Perseverance.[36]

    The final communication from the rover came on June 10, 2018 (sol 5111) from Perseverance Valley,

    Watt-hours for the sol, and the highest atmospheric opacity (tau) ever measured on Mars: 10.8.[38]

    Design and construction

    Main article: Mars Exploration Rover § Scientific instrumentation
    Annotated rover diagram
    Pancam Mast Assembly (PMA)

    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 a rocker-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). Both Spirit and Opportunity have pieces of the fallen World 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 rechargeable

    lithium ion batteries stored energy for use at night. Opportunity's onboard computer uses a 20 MHz RAD6000 CPU with 128 MB of DRAM and 3 MB of EEPROM.[42] The rover's operating temperature ranges from −40 to +40 °C (−40 to 104 °F) and radioisotope 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 Earth. A low-gain antenna was also used to relay data to spacecraft orbiting Mars.[44]

    Science payload

    The science instruments included:[45]

    The rover arm held the following instruments:[46]

    Opportunity was 'driven' by several operators throughout its mission, including JPL roboticist Vandi Verma.[47]

    Power

    Main article: Mars Exploration Rover § Power and electronic systems

    The rover uses a combination of solar cells and a rechargeable chemical battery.

    Eagle 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.[50]

    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.[51] 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.[51] During its first winter power levels dropped to under 300 Wh per day for two months, but some later winters were not as bad.[51]

    Another factor that can reduce received power is dust in the atmosphere, especially dust storms.

    hibernation mode on June 12,[53][54] but it remained silent after the storm subsided in early October.[30]

    Scientific findings

    Main article: Scientific information from the Mars Exploration Rover mission
    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 of

    regolith that hold clues to past water activity on Mars. In addition to investigating the water, Opportunity has also obtained astronomical observations and atmospheric data.[citation needed
    ]

    Legacy and honors

    Following its launch, Opportunity was

    anthropomorphized by its operators: the rover was called a "she," drawing from nautical tradition, and given an affectionate nickname, "Oppy." One scientist, who worked with Opportunity 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."[55]
    The media attention surrounding Opportunity's shutdown spread this usage to the general public.

    With word on February 12, 2019, that NASA was likely to conclude the Opportunity 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 by Opportunity 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, and tributes to the memory of Opportunity.[56]

    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 by Opportunity, 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.[56][57]

    Honoring Opportunity's great contribution to the exploration of Mars, an asteroid was named Opportunity: 39382 Opportunity.[58] The name was proposed by Ingrid van Houten-Groeneveld who, along with Cornelis Johannes van Houten and Tom Gehrels, discovered the asteroid on September 24, 1960. Opportunity's lander is Challenger Memorial Station.[59]

    On March 24, 2015, NASA celebrated Opportunity having traveled the distance of a marathon 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.[60][61]

    Documentary film, Good Night Oppy, about the Opportunity, Spirit, and their long missions, was directed by Ryan White, and included support from JPL and Industrial Light & Magic. It was released in 2022.[62]

    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.[63][64]

    A selection of panoramas from the mission:

    Fram crater
    (Sol 88, April 23, 2004)
    Final panorama image taken by Opportunity between May and June 2018 prior to being disabled by the dust storms
    Panorama of the Opportunity rover team by "Dusty" – a testing replica of the rover on Earth (September 6, 2018)

    See also

    References

    1. ^ a b c Nelson, Jon. "Mars Exploration Rover – Opportunity". NASA. Archived from the original on January 24, 2014. Retrieved February 2, 2014.
    2. ^ a b "Launch Event Details – When did the Rovers Launch?". Archived from the original on February 18, 2009. Retrieved April 25, 2009.
    3. ^ "Mars Exploration Rover project, NASA/JPL document NSS ISDC 2001 27/05/2001" (PDF). p. 5. Archived from the original (PDF) on May 27, 2010. Retrieved April 28, 2009.
    4. ^ McDowell, Jonathan (July 15, 2003). "Jonathan's Space Report No. 504". Jonathan's Space Report. Retrieved February 19, 2021.
    5. ^ a b c Agle, D.C.; Brown, Dwayne; Wendel, JoAnna (February 13, 2019). "NASA's Opportunity Rover Mission on Mars Comes to End". NASA. Retrieved February 14, 2019.
    6. ^ Staff. "Mapping the Mars Roversnd' Landing Sites". Esri. Archived from the original on May 4, 2014. Retrieved May 4, 2014.
    7. ^ a b "Mars Exploration Rover Mission: All Opportunity Updates". nasa.gov. Archived from the original on August 30, 2015. Retrieved September 18, 2018.
    8. ^ "Marvin The Martian and Daffy Duck as Duck Dodgers Prepare for Upcoming NASA Missions to Mars". SpaceNews. May 2, 2003. Retrieved August 6, 2024.
    9. ^ Spirit landed on January 4, 2004.
    10. ^ Malik, T. (June 21, 2018). "Mars Dust Storm 2018: How It Grew & What It Means for the Opportunity Rover". space.com. Future.plc. Retrieved February 14, 2019.
    11. Planetary Society
      . Retrieved February 14, 2019.
    12. ^ "Opportunity on verge of new discovery". wustl.edu. September 14, 2011. Archived from the original on September 24, 2011. Retrieved September 17, 2011.
    13. ^ Amos, Jonathan (February 13, 2019). "Nasa calls time on silent Opportunity Mars rover". BBC. Retrieved February 14, 2019.
    14. ^ Greicius, Tony (September 24, 2018). "Opportunity Emerges in a Dusty Picture". NASA. Archived from the original on October 15, 2018. Retrieved November 30, 2018.
    15. ^ Greicius, Tony (October 29, 2018). "Update on Opportunity Rover Recovery Efforts". NASA. Archived from the original on November 3, 2018. Retrieved February 23, 2022.
    16. ^ a b c "NASA's Opportunity Rover Mission on Mars Comes to End". NASA. February 13, 2019. Retrieved February 13, 2019.
    17. ^ "Objectives – NASA". mars.nasa.gov. Retrieved April 23, 2023.
    18. ^ "Mars Exploration Rover Mission Science Objectives". mars.nasa.gov. Retrieved February 19, 2021.
    19. ^ "Opportunity Update Archive". NASA/JPL. Archived from the original on May 7, 2009. Retrieved May 4, 2009.
    20. ^ Harwood, William (July 8, 2003). "Opportunity launched to Mars". Spaceflight Now. Archived from the original on January 25, 2016. Retrieved December 18, 2015.
    21. ^ "Mars Rover Opportunity – Mars Missions". NASA Jet Propulsion Laboratory (JPL).
    22. ^ Dvorsky, George (February 15, 2019). "The Enduring Mystery of the Martian 'Blueberries' Discovered by Opportunity Rover". Gizmodo. Retrieved February 15, 2019.
    23. ^ "'Endurance Crater' Overview". NASA Jet Propulsion Laboratory. September 11, 2004. Retrieved December 27, 2022.
    24. ^ JPL; NASA (January 19, 2005). "Mars Exploration Rover Mission: Press Releases". NASA. Retrieved December 27, 2022.
    25. ^ "NASA – NASA Mars Rover Arrives at New Site on Martian Surface". Nasa.gov. Archived from the original on June 6, 2012. Retrieved July 15, 2012.
    26. ^ "Mars Exploration Rover Mission: All Opportunity Updates". nasa.gov. Archived from the original on August 30, 2015. Retrieved January 5, 2017.
    27. ^ "Opportunity Updates". Archived from the original on October 12, 2012. Retrieved November 20, 2014.
    28. ^ O'Neill, Ian (December 29, 2014). "Mars Rover Opportunity Suffers Worrying Bouts of 'Amnesia'". Web article. Discovery News. Archived from the original on December 30, 2014. Retrieved December 31, 2014.
    29. ^ "Opportunity Update Archive, sols 4024–4029, May 20, 2015–May 25, 2015". Archived from the original on August 30, 2015. Retrieved July 2, 2015.
    30. ^ a b c "Mars Exploration Rover Mission: All Opportunity Updates". mars.nasa.gov. Archived from the original on March 25, 2018. Retrieved February 10, 2018.
    31. ^ a b Opportunity Rover Still Silent on Mars, 4 Months After Epic Dust Storm Began Archived October 15, 2018, at the Wayback Machine. Mike Wall, Space.com. October 12, 2018.
    32. ^ Torbet, Georgina (January 26, 2019). "NASA makes last-ditch attempt to revive dormant Mars rover Opportunity". digitaltrends.com. Designtechnica Corporation. Retrieved January 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.
    33. ^ Bean, Keri (February 12, 2019). "Tonight is the final planned attempt to contact Opportunity. I had the extreme privilege to be the final Tactical Uplink Lead yesterday. My signature is in pink on the command approval form, as usual. Godspeed, Opportunity. #LoveYouOppy #OppyPhoneHome #WakeUpOppy". @PlanetaryKeri. Retrieved February 16, 2019.
    34. ^ "Mars Exploration Rover Mission: All Opportunity Updates". mars.nasa.gov. Archived from the original on March 25, 2018. Retrieved February 10, 2019.
    35. ^ Oppy, Spirit and (February 12, 2019). "#OppyPhoneHome Update Tonight, we'll make our last planned attempts to contact Opportunity. The solar-powered rover last communicated on June 10, 2018, as a planet-wide dust storm swept across Mars".
    36. ^ a b Chang, Kenneth (February 13, 2019). "NASA's Mars Rover Opportunity Concludes a 15-Year Mission". The New York Times. Retrieved February 13, 2019.
    37. ^ Berger, Eric (February 13, 2019). "Opportunity did not answer NASA's final call, and it's now lost to us". Ars Technica.
    38. ^ "MERB Notebook – Opportunity Mars Rover data". an.rsl.wustl.edu. Retrieved February 18, 2019.
    39. ^ "Mars Exploration Rover Mission: The Mission". marsrovers.jpl.nasa.gov. Archived from the original on October 13, 2013. Retrieved April 23, 2023.
    40. ^ Chang, Kenneth (November 7, 2004). "Martian Robots, Taking Orders From a Manhattan Walk-Up". The New York Times. Retrieved April 9, 2009.
    41. ISBN 978-1-4013-0149-1
      .
    42. ^ "The Rover's "Brains" - NASA". mars.nasa.gov. Retrieved April 23, 2023.
    43. ^ "The Rover's Temperature Controls - NASA". mars.nasa.gov. Retrieved April 23, 2023.
    44. ^ "The Rover's Antennas - NASA". mars.nasa.gov. Retrieved April 23, 2023.
    45. ^ "The Rover's "Eyes" and Other "Senses" - NASA". mars.nasa.gov. Retrieved April 23, 2023.
    46. ^ "The Rover's "Arm" - NASA". mars.nasa.gov. Retrieved April 23, 2023.
    47. ^ Venkatraman, Vijaysree (July 13, 2015). "The space roboticist". Science magazine. Retrieved February 14, 2019.
    48. ^ a b "Mars Exploration Rover Mission: Technology". nasa.gov. Archived from the original on December 28, 2016. Retrieved January 5, 2017.
    49. ^ "Power". Archived from the original on January 18, 2017. Retrieved September 20, 2018.
    50. ^ "Mars Exploration Rover Mission: All Opportunity Updates". nasa.gov. Archived from the original on February 1, 2017. Retrieved January 5, 2017.
    51. ^ a b c mars.nasa.gov. "Mars Rover Opportunity Busy Through Depth of Winter – Mars News". nasa.gov. Archived from the original on July 26, 2016. Retrieved January 5, 2017.
    52. ^ a b c "Europe's ExoMars mission arrives in the middle of dust season". phys.org. Archived from the original on November 30, 2016. Retrieved January 5, 2017.
    53. ^ NASA's Opportunity rover is in a deep sleep on Mars – but there's hope it will wake up again Archived June 14, 2018, at the Wayback Machine. Loren Grush, The Verge. June 13, 2018.
    54. ^ Malik, Tariq. "As Massive Storm Rages on Mars, Opportunity Rover Falls Silent". Scientific American (Space.com). Archived from the original on June 13, 2018. Retrieved June 13, 2018.
    55. ^ Carr, Danielle; Colabrese, Ines (September 21, 2018). "Why scientists have become attached to 'Oppy', the Mars rover stranded by a dust storm". Canadian Broadcasting Corporation. Retrieved March 5, 2023.
    56. ^ a b Margolis, Jacob (February 16, 2019). "How A Tweet About The Mars Rover Dying Blew Up On The Internet And Made People Cry". LAist. Retrieved February 19, 2021.
    57. ^ Georgiou, Aristos (February 18, 2019). "No, the Last Words of NASA's Opportunity Rover Weren't 'My Battery Is Low and It's Getting Dark'". Newsweek. Retrieved February 18, 2019.
    58. ^ "Mars Exploration Rover Mission; "Like Rover, Like Asteroid"". Retrieved February 19, 2021.
    59. ^ "Space Shuttle Challenger Crew Memorialized on Mars". Retrieved February 19, 2021.
    60. ^ "JPL Runners Celebrate Mars Marathon | Mars Video". mars.nasa.gov.
    61. ^ "The First Martian Marathon – NASA Science". science.nasa.gov. Archived from the original on May 18, 2015. Retrieved May 15, 2015.
    62. ^ Ross, Rollo (November 22, 2022). "'Good Night Oppy' about NASA's rover mission may make you cry". Reuters. Retrieved April 23, 2023.
    63. ^ Truong, Brian. "Mars Exploration Rover". nasa.gov. Archived from the original on November 10, 2013. Retrieved November 20, 2013.
    64. ^ "Opportunity Rover Celebrates 5,000 Days on Mars". Space.com. February 16, 2018. Archived from the original on February 17, 2018. Retrieved February 17, 2018.
    Wikimedia Commons has media related to Mars Exploration Rover.
    • Archive of MER progress reports by A.J.S. Rayl at planetary.org
    Retrieved from "https://en.wikipedia.org/w/index.php?title=Opportunity_(rover)&oldid=1243046539"