The planet Mars has been explored remotely by spacecraft. Probes sent from Earth, beginning in the late 20th century, have yielded a large increase in knowledge about the Martian system, focused primarily on understanding its geology and habitability potential. Engineering interplanetary journeys is complicated and the exploration of Mars has experienced a high failure rate, especially the early attempts. Roughly sixty percent of all spacecraft destined for Mars failed before completing their missions, with some failing before their observations could begin. Some missions have been met with unexpected success, such as the twin Mars Exploration Rovers, Spirit and Opportunity, which operated for years beyond their specification.
Current status There are two functional rovers on the surface of Mars, the Curiosity and Perseverance, both operated by the American space agency NASA. Perseverance was accompanied by the Ingenuity helicopter, which scouted sites for Perseverance to study before the helicopter's mission ended in 2024. The Zhurong rover, part of the Tianwen-1 mission by the China National Space Administration (CNSA) was active until 20 May 2022 when it went into hibernation due to approaching sandstorms and Martian winter; the rover was expected to wake up from hibernation in December 2022, but it has not moved and is presumed to be permanently inactive.
There are six orbiters surveying the planet: Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, the Trace Gas Orbiter, the Hope Mars Mission, and the Tianwen-1, which have contributed massive amounts of information about Mars.
In April 2024, NASA selected several companies to begin studies on providing commercial services to further enable robotic science on Mars.
Martian system
Mars has long been the subject of human interest. Early telescopic observations revealed color changes on the surface that were attributed to seasonal vegetation and apparent linear features were ascribed to intelligent design. Further telescopic observations found two moons, Phobos and Deimos, polar ice caps and the feature now known as Olympus Mons, the Solar System's tallest mountain. The discoveries piqued further interest in the study and exploration of the red planet. Mars is a rocky planet, like Earth, that formed around the same time, yet with only half the diameter of Earth, and a thin atmosphere; it has a cold and desert-like surface.
One way the surface of Mars has been categorized, is by thirty "quadrangles", with each quadrangle named for a prominent physiographic feature within that quadrangle.
Launch windows
The minimum-energy launch windows for a Martian expedition occur at intervals of approximately two years and two months (specifically 780 days, the planet's synodic period with respect to Earth). In addition, the lowest available transfer energy varies on a roughly 16-year cycle. For example, a minimum occurred in the 1969 and 1971 launch windows, rising to a peak in the late 1970s, and hitting another low in 1986 and 1988.
+ Launch opportunities Year Window Spacecraft (launched or planned) 2013 Nov MAVEN, Mars Orbiter Mission 2016 Mar ExoMars TGO 2018 May InSight 2020 Jul–Sep (1) Emirates Mars Mission, Hope orbiter(2) Tianwen-1 orbiter, deployable and remote camera, lander and Zhurong rover(3) Mars 2020 Perseverance rover and Ingenuity helicopter 2022 Aug–Nov N/A 2024 Oct–Nov N/A2026Nov–Dec(1) Martian Moons eXploration (MMX)(2) Impulse/Relativity Mars lander(3) ESCAPADE2028/29Dec–Jan (1) Rosalind Franklin(2) Tianwen-32031Feb–AprMars Lander Mission2033Apr–MayN/A2035May–JulN/A2037Jul–SeptN/A2039Sep–OctN/A2041/42Oct–DecN/A2043/44Dec–JanN/A2046Jan–MarN/A
Past missions
Starting in 1960, the Soviet space program launched a series of probes to Mars including the first intended (but unsuccessful) flybys and hard (impact) landing. In November 1962, Mars 2MV-3 No.1 was intended to land on Mars but didn't manage to leave the low Earth orbit and decayed down the Earth's atmosphere, disintegrating progressively. The first successful flyby of Mars was on 14–15 July 1965, by NASA's Mariner 4. On November 14, 1971, Mariner 9 became the first space probe to orbit another planet when it entered into orbit around Mars. The amount of data returned by probes increased substantially as technology improved.NASA PROGRAM & MISSIONS Historical Log . Mars.jpl.nasa.gov. Retrieved on 2012-08-14.
The first to contact the surface were two Soviet probes: Mars 2 lander on November 27 and Mars 3 lander on December 2, 1971. Mars 2's landing system failed during descent and the probe was lost in the subsequent crash. Mars 3 succeeded in the first Martian soft landing.Mars 2 Lander – NASA . Nssdc.gsfc.nasa.gov. Retrieved on 2012-05-10. Mars 6 failed during descent but did return some corrupted atmospheric data in 1974.Mars 6 – NASA . Nssdc.gsfc.nasa.gov. Retrieved on 2012-05-10. The 1975 NASA launches of the Viking program consisted of two orbiters, each with a lander that successfully soft landed in 1976. Viking 1 remained operational for six years, Viking 2 for three years. The Viking landers relayed the first color panoramas of Mars.
The Soviet probes Phobos 1 and 2 were sent to Mars in 1988 to study Mars and its two moons, with a focus on Phobos. Phobos 1 lost contact on the way to Mars. Phobos 2, while successfully photographing Mars and Phobos, failed before it was set to release two landers to the surface of Phobos.
Missions that ended prematurely after Phobos 1 and 2 (1988) include (see Probe difficulties section for more details): Mars Observer (launched in 1992) Mars 96 (1996) Mars Climate Orbiter (1999) Mars Polar Lander with Deep Space 2 (1999) Nozomi (2003) Beagle 2 (2003) Fobos-Grunt with Yinghuo-1 (2011) Schiaparelli lander (2016)
Following the 1993 failure of the Mars Observer orbiter, the NASA Mars Global Surveyor achieved Mars orbit in 1997. This mission was a complete success, having finished its primary mapping mission in early 2001. Contact was lost with the probe in November 2006 during its third extended program, spending exactly 10 operational years in space. The NASA Mars Pathfinder, carrying a robotic exploration vehicle Sojourner, landed in the Ares Vallis on Mars in July 1997, returning many images.
NASA's Mars Odyssey orbiter entered Mars orbit in 2001. Odyssey Gamma Ray Spectrometer detected significant amounts of hydrogen in the upper metre or so of regolith on Mars. This hydrogen is thought to be contained in large deposits of water ice.
The Mars Express mission of the European Space Agency (ESA) reached Mars in 2003. It carried the Beagle 2 lander, which was not heard from after being released and was declared lost in February 2004. Beagle 2 was located in January 2015 by the HiRise camera on NASA's Mars Reconnaissance Orbiter (MRO) having landed safely but failed to fully deploy its solar panels and antenna. In early 2004, the Mars Express Planetary Fourier Spectrometer team announced the orbiter had detected methane in the Martian atmosphere, a potential biosignature. ESA announced in June 2006 the discovery of aurora on Mars by the Mars Express.
In January 2004, the NASA twin Mars Exploration Rovers named Spirit (MER-A) and Opportunity (MER-B) landed on the surface of Mars. Both have met and exceeded all their science objectives. Among the most significant scientific returns has been conclusive evidence that liquid water existed at some time in the past at both landing sites. Martian dust devils and windstorms have occasionally cleaned both rovers' solar panels, and thus increased their lifespan. Spirit rover (MER-A) was active until 2010, when it stopped sending data because it got stuck in a sand dune and was unable to reorient itself to recharge its batteries.
Rosetta came within 250 km of Mars during its 2007 flyby.Space probe performs Mars fly-by . BBC News (2007-02-25). Retrieved on 2012-08-14. Dawn flew by Mars in February 2009 for a gravity assist on its way to investigate Vesta and Ceres.
Phoenix landed on the north polar region of Mars on May 25, 2008. Its robotic arm dug into the Martian soil and the presence of water ice was confirmed on June 20, 2008. The mission concluded on November 10, 2008, after contact was lost. In 2008, the price of transporting material from the surface of Earth to the surface of Mars was approximately US$309,000 per kilogram.
The Indian Space Research Organisation (ISRO) launched their Mars Orbiter Mission (MOM) on November 5, 2013, and it was inserted into Mars orbit on September 24, 2014. India's ISRO is the fourth space agency to reach Mars, after the Soviet space program, NASA and ESA. India successfully placed a spacecraft into Mars orbit, and became the first country to do so in its maiden attempt.
, the Psyche space probe is the latest probe to visit Mars. It flew by the Red Planet as part of a gravity-assist maneuver to adjust its heliocentric trajectory into the same inclination as its target asteroid, 16 Psyche. The probe flew as close as above the surface of Mars. Because Psyche approached Mars at a high phase angle, the planet appeared as a thin crescent before the close flyby, illuminated by sunlight reflected from its surface.
Overview of missions The following entails a brief overview of previous missions to Mars, oriented towards orbiters and flybys; see also Mars landing and Mars rover.
Early Soviet missions
1960s
Between 1960 and 1969, the Soviet Union launched nine probes intended to reach Mars. They all failed: three at launch; three failed to reach near-Earth orbit; one during the burn to put the spacecraft into trans-Mars trajectory; and two during the interplanetary orbit.
The Mars 1M programs (sometimes dubbed Mars-nik in Western media) was the first Soviet uncrewed spacecraft interplanetary exploration program, which consisted of two flyby probes launched towards Mars in October 1960, Mars 1960A and Mars 1960B (also known as Korabl 4 and Korabl 5 respectively). After launch, the third stage pumps on both launchers were unable to develop enough pressure to commence ignition, so Earth parking orbit was not achieved. The spacecraft reached an altitude of 120 km before reentry.
Mars 1962A was a Mars flyby mission, launched on October 24, 1962, and Mars 1962B an intended first Mars lander mission, launched in late December of the same year (1962). Both failed from either breaking up as they were going into Earth orbit or having the upper stage explode in orbit during the burn to put the spacecraft into trans-Mars trajectory.
The first success
+ Selected Soviet Mars probes Spacecraft Orbiter or flyby outcome Lander outcome Mars 1 Mars 2 Mars 3 Mars 4 Mars 5 Mars 6 Mars 7 Phobos 1 Phobos 2 Mars 1 (1962 Beta Nu 1), an automatic interplanetary spacecraft launched to Mars on November 1, 1962, was the first probe of the Soviet Mars probe program to achieve interplanetary orbit. Mars 1 was intended to fly by the planet at a distance of about 11,000 km and take images of the surface as well as send back data on cosmic radiation, micrometeoroid impacts and Mars's magnetic field, radiation environment, atmospheric structure, and possible organic compounds. Sixty-one radio transmissions were held, initially at 2-day intervals and later at 5-day intervals, from which a large amount of interplanetary data was collected. On 21 March 1963, when the spacecraft was at a distance of 106,760,000 km from Earth, on its way to Mars, communications ceased due to failure of its antenna orientation system.
In 1964, both Soviet probe launches, of Zond 1964A on June 4, and Zond 2 on November 30, (part of the Zond program), resulted in failures. Zond 1964A had a failure at launch, while communication was lost with Zond 2 en route to Mars after a mid-course maneuver, in early May 1965.