Opportunity, also known as MER-B (Mars Exploration Rover – B) or MER-1, is a robotic rover active on the planet Mars since 2004.[1] Launched on July 7, 2003, Opportunity landed on Mars' Meridiani Planum on January 25, 2004 at 05:05 Ground UTC (about 13:15 Mars local time), three weeks after its twin Spirit (MER-A), also part of NASA's Mars Exploration Rover Mission, touched down on the other side of the planet.[6] With a planned 90 sol (Martian days) duration of activity, Spirit functioned until getting stuck in 2009 and ceased communications in 2010, while Opportunity remains active as of 2015, having already exceeded its operating plan by 700110000000000000010 years, 7002258000000000000258 days (in Earth time). Opportunity has continued to move, gather scientific observations, and report back to Earth for over 40 times its designed lifespan. On July 28, 2014, NASA announced that Opportunity, after having traveled over 40 km (25 mi) on the planet Mars, has set a new "off-world" record as the rover having driven the greatest distance, surpassing the previous record held by the Soviet Union's Lunokhod 2 rover, which had traveled 39 km (24 mi) on the Moon.[7][8]
Mission highlights include the initial 90 sol mission, finding extramartian meteorites such as Heat Shield Rock (Meridiani Planum meteorite), and over two years studying Victoria crater. It survived dust-storms and reached Endeavour crater in 2011, which has been described as a "second landing site".[9]
Delta II Heavy (7925H-9.5) lifting off from pad 17-B carrying MER-B in 2003 with Opportunity rover.
The scientific objectives of the Mars Exploration Rover mission are to:[10]
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, evaporation, sedimentary cementation or 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 instruments. This will help determine the accuracy and effectiveness of various instruments that survey Martian geology 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 and textures of rocks and soils and 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.
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.
Opportunity (along with its twin, Spirit) is a six-wheeled, solar-powered robot 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 enable mobility. 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 5 centimetres per second (2.0 in/s) although average speed is about a fifth of this (0.89 centimetres per second (0.35 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".[11][12]
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 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.[13] A gold film and a layer of silica aerogel 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.
The primary surface mission for Opportunity was planned to last 90 sols. The mission has received several extensions and has been operating for 4002 days since landing. An archive of weekly updates on the rover's status can be found at the Opportunity Update Archive.[14]
From its initial landing, by chance, into an impact crater 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 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, which it investigated from June – December 2004. 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.
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, 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; 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.[15] Here 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. At May 2013 the rover was heading south to a hill named Solander Point.
Opportunity's total odometry as of December 17, 2014 (sol 3874) is 41.41 km (25.73 mi).[16] 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).[16]
In December 2014, NASA reported that Opportunity was suffering from "amnesia" events in which the rover fails to write data, e.g. telemetry information, to non-volatile memory. The hardware failure is believed to be due to an age-related fault in one of the rover's seven memory banks. As a result, NASA aims to force the rover's software to ignore the failed memory bank.[17]
Opportunity has provided substantial evidence in support of the mission's primary scientific goals: to search for and characterize a wide range of rocks and soils that hold clues to past water activity on Mars. In addition to investigating the water, Opportunity has also obtained astronomical observations and atmospheric data.
The rover can take pictures with its different cameras, but only the PanCam camera has the ability to photograph a scene with different color filters. The panorama views are usually built up from PanCam images. As of November 20, 2013, Opportunity rover had returned 186,246 pictures.[20]
Views
Opportunity views the empty lander, the Challenger Memorial Station.
Pancam view from August 2012 (Sol 3058)
Solander Point is visible on the horizon; foreground shows Botany Bay.[21]
Opportunity on a Martian crater (simulated view).
Panoramas
360° Panorama at crater triplet, all three craters in right half of image, Naturaliste Crater in foreground.
Panorama taken on the rim of Erebus crater. The rover's solar panels are seen on the lower half
"Blueberries" (hematite spheres) on a rocky outcrop at Eagle Crater. Note the merged triplet in the upper left.
"Newberries": This view displays an area about 6 centimeters across. It was taken at an outcrop named Kirkwood at the Cape York on the rim of Endeavour crater on Mars. The spheres seen here are about 3 millimeters in diameter. The Microscopic Imager took this image at the 3064 sol.
From orbit
Opportunity landing site, lander, as imaged by MRO
(November 29, 2006)
Opportunity landing site, parachute and backshell, as imaged by MRO (November 29, 2006)
Opportunity landing site, heat shield, as imaged by MRO
(November 29, 2006)
Opportunity (circled) as seen by HiRISE on January 29, 2009. Endeavour Crater is 17 km (11 mi) away.
Maps
Opportunity traverse map, from sol 1 (2004) through sol 2055 (2009)
Annotated Opportunity traverse map as of December 8, 2010 (Sol 2442)
Annotated Opportunity traverse map as of June 11, 2014 (Sol 3689)
Opportunity's traverse on Cape York from Sol 2678 to Sol 3317 with some additional annnotations of the main features.
Payloads are separated by bullets ( · ), launches by pipes ( | ). Manned flights are indicated in bold text. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in brackets.