A rover (or sometimes planetary rover) is a

planetary surface A planetary surface is where the solid or liquid material of certain types of astronomical objects contacts the atmosphere or outer space. Planetary surfaces are found on solid objects of planetary mass, including terrestrial planets (including ...

exploration Exploration refers to the historical practice of discovering remote lands. It is studied by geographers and historians. Two major eras of exploration occurred in human history: one of convergence, and one of divergence. The first, covering most ...

device designed to move across the solid surface on a

planet A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...

or other

planetary mass In astronomy, planetary mass is a measure of the mass of a planet-like astronomical object. Within the Solar System, planets are usually measured in the astronomical system of units, where the unit of mass is the solar mass (), the mass of the Su ...

celestial bodies. Some rovers have been designed as

land vehicle A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), wate ...

s to transport members of a

human spaceflight Human spaceflight (also referred to as manned spaceflight or crewed spaceflight) is spaceflight with a crew or passengers aboard a spacecraft, often with the spacecraft being operated directly by the onboard human crew. Spacecraft can also be ...

crew; others have been partially or fully

autonomous robot An autonomous robot is a robot that acts without recourse to human control. The first autonomous robots environment were known as Elmer and Elsie, which were constructed in the late 1940s by W. Grey Walter. They were the first robots in history ...

s. Rovers are typically created to land on another planet (other than

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

) via a lander-style

spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...

, tasked to collect information about the terrain, and to take crust samples such as dust, soil, rocks, and even liquids. They are essential tools in

space exploration Space exploration is the use of astronomy and space technology to explore outer space. While the exploration of space is carried out mainly by astronomers with telescopes, its physical exploration though is conducted both by robotic spacec ...

Features

Rovers arrive on spacecraft and are used in conditions very distinct from those on the Earth, which makes some demands on their design.

Reliability

Rovers have to withstand high levels of acceleration, high and low temperatures,

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

, dust,

corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...

cosmic rays Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...

, remaining functional without repair for a needed period of time. Sojourner in cruise configuration

Autonomy

Rovers which land on celestial bodies far from the Earth, such as the

Mars Exploration Rovers NASA's Mars Exploration Rover (MER) mission was a robotic space mission involving two Mars rovers, ''Spirit (rover), Spirit'' and ''Opportunity (rover), Opportunity'', exploring the planet Mars. It began in 2003 with the launch of the two rover ...

, cannot be remotely controlled in real-time since the speed at which radio signals travel is far too slow for ''real-time'' or ''near-real-time'' communication. For example, sending a signal from Mars to Earth takes between 3 and 21 minutes. These rovers are thus capable of operating autonomously with little assistance from ground control as far as

navigation Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, ...

and

data acquisition Data acquisition is the process of sampling signals that measure real-world physical conditions and converting the resulting samples into digital numeric values that can be manipulated by a computer. Data acquisition systems, abbreviated by the acro ...

are concerned, although they still require human input for identifying promising targets in the distance to which to drive, and determining how to position itself to maximize solar energy. Giving a rover some rudimentary visual identification capabilities to make simple distinctions can allow engineers to speed up the reconnaissance. During the NASA Sample Return Robot Centennial Challenge, a rover, named ''Cataglyphis'', successfully demonstrated autonomous navigation, decision-making, and sample detection, retrieval, and return capabilities.

Non-wheeled approaches

Other rover designs that do not use wheeled approaches are possible. Mechanisms that utilize "walking" on robotic legs, hopping, rolling, etc. are possible. For example,

Stanford University Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is consider ...

researchers have proposed "Hedgehog", a small

cube In geometry, a cube is a three-dimensional solid object bounded by six square faces, facets or sides, with three meeting at each vertex. Viewed from a corner it is a hexagon and its net is usually depicted as a cross. The cube is the only r ...

-shaped rover that can controllably hop—or even spin out of a sandy sinkhole by corkscrewing upward to escape—for surface exploration of

low gravity Weightlessness is the complete or near-complete absence of the sensation of weight. It is also termed zero gravity, zero G-force, or zero-G. Weight is a measurement of the force on an object at rest in a relatively strong gravitational fie ...

celestial bodies.

History

Lunokhod 0 (No.201)

The Soviet rover was intended to be the first roving remote-controlled

robot A robot is a machine—especially one programmable by a computer—capable of carrying out a complex series of actions automatically. A robot can be guided by an external control device, or the control may be embedded within. Robots may be c ...

on the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

, but crashed during a failed start of the launcher 19 February 1969.

Lunokhod 1

The

Lunokhod 1 ''Lunokhod 1'' ( Russian: Луноход-1 ("Moonwalker 1"), also known as Аппарат 8ЕЛ № 203 ("Device 8EL No. 203")) was the first of two robotic lunar rovers landed on the Moon by the Soviet Union as part of its Lunokhod program. The ...

rover landed on the Moon in November 1970. It was the first roving remote-controlled robot to land on any celestial body. The

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

launched Lunokhod 1 aboard the

Luna 17 ''LOK Luna 17'' (Ye-8 series) was an unmanned space mission of the Luna program, also called ''Lunik 17''. It deployed the first robotic rover onto the surface of the Moon. Launch ''Luna 17'' was launched from an Earth parking orbit towards ...

spacecraft on November 10, 1970, and it entered lunar orbit on November 15. The spacecraft soft-landed in the

Sea of Rains Mare Imbrium (Latin ''imbrium'', the "Sea of Showers" or "Sea of Rains", "Sea of Tears") is a vast lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System. The Imbrium Basin formed from the collis ...

region on November 17. The lander had dual ramps from which Lunokhod 1 could descend to the lunar surface, which it did at 06:28 UT. From November 17, 1970, to November 22, 1970, the rover drove 197 m, and during 10 communication sessions returned 14 close up pictures of the Moon and 12 panoramic views. It also analyzed the lunar soil. The last successful communications session with Lunokhod 1 was on September 14, 1971. Having worked for 11 months, Lunokhod 1 held the durability record for space rovers for more than 30 years, until a new record was set by the

Mars Exploration Rover NASA's Mars Exploration Rover (MER) mission was a robotic space mission involving two Mars rovers, ''Spirit (rover), Spirit'' and ''Opportunity (rover), Opportunity'', exploring the planet Mars. It began in 2003 with the launch of the two rover ...

Apollo Lunar Roving Vehicle

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

included

Lunar Roving Vehicle The Lunar Roving Vehicle (LRV) is a battery-powered four-wheeled rover used on the Moon in the last three missions of the American Apollo program ( 15, 16, and 17) during 1971 and 1972. It is popularly called the Moon buggy, a play on the t ...

s in three

Apollo Apollo, grc, Ἀπόλλωνος, Apóllōnos, label=genitive , ; , grc-dor, Ἀπέλλων, Apéllōn, ; grc, Ἀπείλων, Apeílōn, label=Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, Áploun, la, Apollō, la, Apollinis, label= ...

missions:

Apollo 15 Apollo 15 (July 26August 7, 1971) was the ninth crewed mission in the United States' Apollo program and the fourth to Moon landing, land on the Moon. It was the first List of Apollo missions#Alphabetical mission types, J mission, with a ...

(which landed on the Moon July 30, 1971),

Apollo 16 Apollo 16 (April 1627, 1972) was the tenth crewed mission in the United States Apollo space program, administered by NASA, and the fifth and penultimate to land on the Moon. It was the second of Apollo's " J missions", with an extended sta ...

(which landed April 21, 1972), and

Apollo 17 Apollo 17 (December 7–19, 1972) was the final mission of NASA's Apollo program, the most recent time humans have set foot on the Moon or traveled beyond low Earth orbit. Commander Gene Cernan and Lunar Module Pilot Harrison Schmitt walked on ...

(which landed December 11, 1972).

Lunokhod 2

The

Lunokhod 2 ''Lunokhod 2'' (russian: Луноход-2 ("Moonwalker 2"), also known as Аппарат 8ЕЛ № 204 ("Device 8EL No. 204")) was the second of two unmanned lunar rovers that landed on the Moon by the Soviet Union as part of the Lunokhod progr ...

was the second of two

unmanned An uncrewed vehicle or unmanned vehicle is a vehicle without a person on board. Uncrewed vehicles can either be under telerobotic control—remote controlled or remote guided vehicles—or they can be autonomously controlled—autonomous vehicl ...

lunar rovers landed on the

by the

as part of the

Lunokhod program Lunokhod ( rus, Луноход, p=lʊnɐˈxot, "Moonwalker") was a series of Soviet robotic lunar rovers designed to land on the Moon between 1969 and 1977. Lunokhod 1 was the first roving remote-controlled robot to land on an extraterrestrial ...

. The rover became operational on the

on January 16, 1973. It was the second roving remote-controlled

to land on any celestial body. The

launched Lunokhod 2 aboard the

Luna 21 ''Luna 21'' (Ye-8 series) was an unmanned space mission, and its spacecraft, of the Luna program, also called ''Lunik 21'', in 1973. The spacecraft landed on the Moon and deployed the second Soviet lunar rover, ''Lunokhod 2''. The primary obje ...

spacecraft on January 8, 1973, and the spacecraft soft-landed in the eastern edge of the

Mare Serenitatis Mare Serenitatis (Latin ''serēnitātis'', the "Sea of Serenity") is a lunar mare located to the east of Mare Imbrium on the Moon. Its diameter is . Geology Mare Serenitatis is located within the Serenitatis basin, which is of the Nectarian ep ...

region on January 15, 1973. Lunokhod 2 descended from the lander's dual ramps to the lunar surface at 01:14 UT on January 16, 1973. Lunokhod 2 operated for about four months, covered of terrain, including hilly upland areas and

rille Rille (German for 'groove') is typically used to describe any of the long, narrow depressions in the surface of the Moon that resemble channels. The Latin term is ''rima'', plural ''rimae''. Typically, a rille can be several kilometers wid ...

s, and sent back 86 panoramic images and over 80,000 TV pictures. Based on wheel rotations Lunokhod 2 was thought to have covered but Russian scientists at the Moscow State University of Geodesy and Cartography (MIIGAiK) have revised that to an estimated distance of about based on Lunar Reconnaissance Orbiter ( LRO) images of the lunar surface. Subsequent discussions with their American counterparts ended with an agreed-upon final distance of , which has stuck since.

PrOP-M

The Soviet Mars 2 and Mars 3 landers each had a small 4.5 kg Mars rover on board, which would have moved across the surface on

skis A ski is a narrow strip of semi-rigid material worn underfoot to glide over snow. Substantially longer than wide and characteristically employed in pairs, skis are attached to ski boots with ski bindings, with either a free, lockable, or partial ...

while connected to the lander with a 15-meter umbilical. Two small metal rods were used for autonomous obstacle avoidance, as radio signals from Earth would have taken too long to drive the rovers using remote control. The rover was planned to be placed on the surface after landing by a manipulator arm and to move in the field of view of the television cameras and stop to make measurements every 1.5 meters. The rover tracks in the Martian soil would also have been recorded to determine material properties. Because of the crash landing of Mars 2 and the communication failure (15 seconds post landing) of Mars 3, neither rover was deployed.

Lunokhod 3

The Soviet rover was intended to be the third roving remote-controlled robot on the Moon in 1977. The mission was canceled due to lack of launcher availability and funding, although the rover was built.

Marsokhod

The Marsokhod was a Soviet rover (hybrid, with both controls

telecommand A telecommand or telecontrol is a command sent to control a remote system or systems not directly connected (e.g. via wires) to the place from which the telecommand is sent. The word is derived from ''tele'' = remote (Greek), and ''command'' = to ...

and automatic) aimed at Mars, part of the Mars 4NM and scheduled to commence after 1973 (according to the plans of 1970). It was to be launched by a

N1 rocket The N1/L3 (from , "Carrier Rocket"; Cyrillic: Н1) was a super heavy-lift launch vehicle intended to deliver payloads beyond low Earth orbit. The N1 was the Soviet counterpart to the US Saturn V and was intended to enable crewed travel to the ...

, which never flew successfully.

''Sojourner''

The

Mars Pathfinder ''Mars Pathfinder'' (''MESUR Pathfinder'') is an American robotic spacecraft that landed a base station with a roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight, wheeled robot ...

mission included ''Sojourner'', the first rover to successfully deploy on another planet.

, the space agency of the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, launched Mars Pathfinder on 4 December 1996; it landed on

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

in a region called

Chryse Planitia Chryse Planitia (Greek, "''Golden Plain''") is a smooth circular plain in the northern equatorial region of Mars close to the Tharsis region to the west, centered at . Chryse Planitia lies partially in the Lunae Palus quadrangle, partially in t ...

on 4 July 1997. From its landing until the final data transmission on 27 September 1997, Mars Pathfinder returned 16,500 images from the lander and 550 images from ''Sojourner'', as well as data from more than 15 chemical analyses of rocks and soil and extensive data on winds and other weather factors.

Beagle 2 Planetary Undersurface Tool

Beagle 2 The ''Beagle 2'' is an inoperative British Mars lander that was transported by the European Space Agency's 2003 ''Mars Express'' mission. It was intended to conduct an astrobiology mission that would have looked for evidence of past life on Mar ...

was designed to explore Mars with a small "mole" (Planetary Undersurface Tool, or PLUTO), to be deployed by the arm. PLUTO had a compressed spring mechanism designed to enable it to move across the surface at a rate of 20 mm per second and to burrow into the ground, collecting a subsurface sample in a cavity in its tip. Beagle 2 failed while attempting to land on Mars in 2003.

Mars Exploration Rover ''Spirit''

''Spirit'' is a robotic rover on Mars, active from 2004 to 2010. It was one of two rovers of

's ongoing

mission. It landed successfully on

at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, ''

Opportunity Opportunity may refer to: Places * Opportunity, Montana, an unincorporated community, United States * Opportunity, Nebraska, an unincorporated community, United States * Opportunity, Washington, a former census-designated place, United States * 3 ...

'' (MER-B), landed on the other side of the planet. Its name was chosen through a NASA-sponsored student essay competition. The rover became stuck in late 2009, and its last communication with Earth was sent on March 22, 2010.

Chang'e 3's Yutu Rover

Chang'e 3 Chang'e 3 (; ) is a robotic lunar exploration mission operated by the China National Space Administration (CNSA), incorporating a robotic lander and China's first lunar rover. It was launched in December 2013 as part of the second phase of t ...

is a Chinese Moon mission that includes a

robotic Robotics is an interdisciplinarity, interdisciplinary branch of computer science and engineering. Robotics involves design, construction, operation, and use of robots. The goal of robotics is to design machines that can help and assist human ...

lunar rover A lunar rover or Moon rover is a space exploration vehicle designed to move across the surface of the Moon. The Apollo Program's Lunar Roving Vehicle was driven on the Moon by members of three American crews, Apollo 15, 16, and 17. Other rov ...

''Yutu'', named after the pet rabbit of Chang'e, the goddess of the Moon in Chinese mythology. Launched in 2013 with the

mission, it is China's first lunar rover, the first soft landing on the Moon since 1976 and the first rover to operate there since the Soviet

ceased operations on 11 May 1973. It was deployed on the Moon on December 14, 2013, and the rover encountered operational difficulties toward the end of the second lunar day after surviving and recovering successfully the first 14-day lunar night (about a month on the Moon), and was unable to move after the end of the second lunar night, though it continued to gather useful information for some months afterward. In October 2015, ''Yutu'' set the record for the longest operational period for a rover on the Moon. On 31 July 2016, ''Yutu'' ceased to operate after a total of 31 months, well beyond its original expected lifespan of three months.

Mars Exploration Rover ''Opportunity''

''Opportunity'' is a robotic rover on the planet Mars, active from 2004 to early 2019. Launched from

on July 7, 2003, it landed on the

Martian Mars, the fourth planet from the Sun, has appeared as a setting in works of fiction since at least the mid-1600s. It became the most popular celestial object in fiction in the late 1800s as the Moon was evidently lifeless. At the time, the pr ...

Meridiani Planum The Meridiani Planum (alternately Meridiani plain, Meridiani plains, Terra Meridiani, or Terra Meridiani plains) is either a large plain straddling the equator of Mars and covered with a vast number of spherules containing a lot of iron oxide or ...

on January 25, 2004, at 05:05 Ground UTC (about 13:15

local time Local time is the time observed in a specific locality. There is no canonical definition. Originally it was mean solar time, but since the introduction of time zones it is generally the time as determined by the time zone in effect, with daylight s ...

), three weeks after its twin ''

Spirit Spirit or spirits may refer to: Liquor and other volatile liquids * Spirits, a.k.a. liquor, distilled alcoholic drinks * Spirit or tincture, an extract of plant or animal material dissolved in ethanol * Volatile (especially flammable) liquids, ...

'' (MER-A) touched down on the other side of the planet. On July 28, 2014, NASA announced that ''Opportunity'', after having traveled over on the planet

, 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 that had traveled . ( related image)

Active rover missions

Active Mars rover locations in context

Mars Science Laboratory Rover ''Curiosity''

PIA16239 High-Resolution Self-Portrait by Curiosity Rover Arm Camera

On 26 November 2011, NASA's

Mars Science Laboratory Mars Science Laboratory (MSL) is a robotic spacecraft, robotic space probe mission to Mars launched by NASA on November 26, 2011, which successfully landed ''Curiosity (rover), Curiosity'', a Mars rover, in Gale (crater), Gale Crater on August ...

mission was successfully launched for Mars. The mission successfully landed the robotic ''Curiosity'' rover on the surface of Mars in August 2012. The rover is currently helping to determine whether Mars could ever have supported life, and search for evidence of past or present

life on Mars The possibility of life on Mars is a subject of interest in astrobiology due to the planet's proximity and similarities to Earth. To date, no proof of past or present life has been found on Mars. Cumulative evidence suggests that during the ...

''Yutu-2'' (Chang'e 4 rover)

Chinese mission launched 7 December 2018, landed and deployed rover 3 January 2019 on the

far side of the Moon The far side of the Moon is the lunar hemisphere that always faces away from Earth, opposite to the Near side of the Moon, near side, because of synchronous rotation in the Moon's orbit. Compared to the near side, the far side's terrain is ru ...

. It was the first ever rover that operates on the far side of the Moon. In December 2019, ''Yutu 2'' broke the lunar longevity record, previously held by the Soviet Union's ''

'' rover, which operated on the lunar surface for eleven lunar days (321 Earth days) and traversed a total distance of . In February 2020, Chinese astronomers reported, for the first time, a high-resolution image of a lunar ejecta sequence, and, as well, direct analysis of its internal architecture. These were based on observations made by the Lunar Penetrating Radar (LPR) on board the ''Yutu-2'' rover while studying the

Mars 2020 ''Perseverance'' rover

PIA22103-Mars2020Rover-23Cameras-20171031

The ''Perseverance'' rover of the

Mars 2020 Mars 2020 is a Mars rover mission forming part of NASA's Mars Exploration Program that includes the rover '' Perseverance'', the small robotic, coaxial helicopter '' Ingenuity'', and associated delivery vehicles. Mars 2020 was launched from ...

mission is a

rover developed by

which was launched in 2020 and landed on Mars on February 18, 2021. It is intended to investigate an astrobiologically relevant ancient environment on Mars, investigate its surface

geological processes Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...

and history, including the assessment of its past

habitability Habitability refers to the adequacy of an environment for human living. Where housing is concerned, there are generally local ordinances which define habitability. If a residence complies with those laws it is said to be habitable. In extreme e ...

and potential for preservation of

biosignature A biosignature (sometimes called chemical fossil or molecular fossil) is any substance – such as an element, isotope, or molecule – or phenomenon that provides scientific evidence of past or present life. Measurable attribute ...

s within accessible geological materials.

Tianwen-1 ''Zhurong''

Tianwen-1 -1 (TW-1; zh, t=, s=, l='Heavenly Questions') is an interplanetary mission by the China National Space Administration (CNSA) which sent a robotic spacecraft to Mars, consisting of 6 spacecraft: an orbiter, two deployable cameras, lander, rem ...

, a

CNSA China National Space Administration (CNSA; ) is the government agency of the People's Republic of China that is responsible for civil space administration and international space cooperation, including organizing or leading foreign exchanges ...

project, launched on July 23, 2020, and successfully reached Mars orbit on February 10, 2021. The

Zhurong Zhurong (), also known as Chongli (), is an important personage in Chinese mythology and Chinese folk religion. According to the '' Huainanzi'' and the philosophical texts of Mozi and his followers, Zhurong is a god of fire and of the south. Th ...

rover landed on Mars on May 14, 2021, and was deployed from lander on 22 May 2021. It will conduct scientific missions.

Planned rover missions

Chandrayaan 3

Chandrayaan-3 is a proposed mission by India, consisting of a lunar lander and a rover. It would be a re-attempt to demonstrate soft landing, following the failure of

Chandrayaan-2 Chandrayaan-2 (, ; ) is the second lunar exploration mission developed by the Indian Space Research Organisation (ISRO), after Chandrayaan-1. It consists of a lunar orbiter, and also included the ''Vikram'' lander, and the ''Pragyan'' lunar ...

's ''Vikram'' lander.

ExoMars ''Rosalind Franklin''

The European Space Agency (ESA) has designed and carried out early prototyping and testing of the ''

Rosalind Franklin Rosalind Elsie Franklin (25 July 192016 April 1958) was a British chemist and X-ray crystallographer whose work was central to the understanding of the molecular structures of DNA (deoxyribonucleic acid), RNA (ribonucleic acid), viruses, co ...

'' rover. , the rover is scheduled for launch in late 2022.

References

{{DEFAULTSORT:Rover (Space Exploration) Off-road vehicles Spacecraft Soviet inventions Russian inventions Space robots