Since the dawn of the space age, Mars has been the target of orbiters, landers and rovers. More than 40 missions have attempted to reach the Red Planet, with varying degrees of success. This page lists these missions, chronologically by launch date, and provides a brief summary of those which had most impact on our knowledge of this planet.
Missions to Mars
Marsnik 1 (Korabl 4) (USSR)
Marsnik 2 (Korabl 5) (USSR)
Sputnik 22 (Korabl 11) (USSR)
Mars 1 (Sputnik 23) (USSR)
Sputnik 24 (Korabl 13) (USSR)
Mariner 3 (US)
Mariner 4 (US)
Zond 2 (USSR)
Mariner 6 (US)
Mariner 7 (US)
Mars 1969A (USSR)
Mars 1969B (USSR)
Mariner 8 (US)
Kosmos 419 (USSR)
Mars 2 (USSR)
Mars 3 (USSR)
Mariner 9 (US)
Mariner 9 was the first spacecraft to orbit another planet. It was planned as part of a two-spacecraft mission, but Mariner 8 was lost during launch. The 560 kg spacecraft circled Mars twice each day for a full year, photographing the surface and analysing the atmosphere with infrared and ultraviolet instruments. The spacecraft gathered data on the atmospheric composition, density, pressure, and temperature as well as the surface composition and topography of Mars. When Mariner 9 first arrived, Mars was almost totally obscured by dust storms, which persisted for more than a month. After the dust cleared, it revealed for the first time a number of gigantic volcanoes and a huge canyon system stretching 4800 km across its surface. More surprisingly, ancient river beds were carved in the landscape of the seemingly dry and dusty planet. Mariner 9 photo-mapped the planet's entire surface. It also took the first close-up pictures of the tiny Martian moons, Deimos and Phobos.
Mars 4 (USSR)
Mars 5 (USSR)
Mars 6 (USSR)
Mars 7 (USSR)
Viking 1 (US)
Two identical Viking spacecraft, each consisting of a lander and an orbiter, were built. Each orbiter-lander pair flew together and entered Mars orbit; the landers then separated and descended to the planet's surface. Three terminal descent engines provided attitude control and reduced the lander's velocity after parachute separation. The landers' electricity was provided by radioactive power sources.
The orbiters found that atmospheric pressure varies by 30 per cent during the Martian year because carbon dioxide condenses and vaporises at the polar caps. The permanent north cap was shown to be made of water ice, while the southern cap retains some carbon dioxide ice through the summer.
The landers each carried a scoop to collect surface material. This was analysed in a small laboratory. The results were contradictory, but it was generally accepted that no evidence of Mars microbes was found.
Viking 1 reached Mars first and one month later, after a safe site was selected from orbiter images, its lander touched down on the western slope of Chryse Planitia. It was the first American mission to land safely on the surface of Mars. The orbiter spent more than four years imaging the surface and studying the atmosphere. The lander operated for well over six years.
Viking 2 (US)
Viking 2 arrived in Mars orbit some seven weeks after Viking 1. The Viking 2 Lander touched down on another lowland region, Utopia Planitia. The landing site was further north than that of the Viking 1 Lander, and on the opposite side of the planet. The orbiter operated for almost two years. The lander operated on the surface for 1281 Mars days and was turned off when its batteries failed.
Phobos 1 (USSR)
Phobos 2 (USSR)
Mars Observer (US)
Mars Global Surveyor (US)
During its primary mapping mission from March 1999 until January 2001, NASA's Mars Global Surveyor collected more information than any previous Mars mission. The orbiter continued to examine Mars' surface and monitor its global weather patterns through three mission extensions, operating longer than any previous spacecraft sent to Mars at the time. It was five days short of the 10th anniversary of its launch (and just one month into its 4th mission extension) when it stopped communicating with Earth. Mars Global Surveyor returned more than 240 000 images and 206 million spectrometer measurements. Its laser altimeter fired 671 million times, resulting in the creation of a nearly global map of the planet's topography.
Mars 96 (Russia)
Mars Pathfinder and Sojourner (US)
The first completed project in NASA's Discovery Programme of low-cost planetary missions, Pathfinder was a technology demonstration as well as a scientific mission. Its final descent used a parachute, then 24 airbags inflated and the parachute was cut free. After bouncing across the surface, the spacecraft came to rest on the floor of an ancient flood channel known as Ares Vallis.
The 10 kg Sojourner rover trundled down a ramp from the lander and onto the rock-covered plains. It moved slowly around the landing site for the next 83 Martian days, until communications transmitted via the lander stopped on 27 September 1997, possibly caused by a flat battery on the lander and a subsequent drop in operating temperature.
Dozens of rocks were photographed from close range and more than a dozen were chemically analysed by Sojourner's X-ray spectrometer. Many seemed to be volcanic in origin, though others contained rounded pebbles, suggesting that running water was involved in their formation. The lander and rover returned more than 17 000 images, chemical analyses of rocks and soil, and extensive data on winds, temperature etc.
Mars Climate Orbiter (Mars Surveyor '98 Orbiter) (US)
Mars Polar Lander (Mars Surveyor '98 Lander) / Deep Space 2 (US)
2001 Mars Odyssey (formerly Mars Surveyor 2001 Orbiter) (US)
After arriving at Mars, Odyssey used the upper atmosphere to move into a 400 km polar mapping orbit – a process known as aerobraking. Its gamma-ray suite recorded significant quantities of hydrogen close to the surface - evidence of large deposits of underground water ice. Analysis of temperature data enabled scientists to distinguish between solid rock and a variety of loose surface materials. Odyssey's camera system examined the planet in both visible-light and infrared wavelengths, identified minerals in rocks and soils and compiled the highest resolution global map of Mars. Its instruments have monitored the Martian atmosphere and measured high-energy radiation. Odyssey is the longest-working spacecraft ever sent to Mars, continually mapping the planet while providing communications relay support for ongoing surface missions.
Mars Express (ESA) / Beagle 2 (UK)
The Mars Express orbiter has been returning colour images and other data since January 2004. Over 95 per cent of the surface has been imaged by the high-resolution camera, with two thirds mapped at a resolution of 20 m per pixel or better, and much of it in stereo. Its spectrometer found deposits of clay minerals indicating an ancient wet environment that was low in acidity. It also carries a ground-penetrating radar to examine ice-rich layered deposits covering the polar regions, and an instrument for studying how the solar wind removes water vapour from Mars' outer atmosphere. A series of close flybys of the moon Phobos is shedding new light on the satellite's interior and origin.
Mars Exploration Rovers A (Spirit) and B (Opportunity) (US)
Two identical spacecraft which each comprised a cruise stage, a 365 kg lander and a 174 kg rover. The six-wheeled rovers were powered by solar panels. They carried two high-resolution colour, stereo cameras as well as navigation cameras, hazard-identification cameras and a microscopic imager - a combination of a microscope and a camera. Other instruments on a robotic arm measured the composition of the surface. A rock abrasion tool uses a grinding wheel to remove dust and weathered rock, exposing fresh rock underneath.
Spirit was the first to land on Mars. It landed in an ancient impact structure, the 150 km wide Gusev crater, that appears to have held a lake long ago. The rover's main task was to search for sedimentary rocks that have been chemically altered by water. Such wet environments could indicate that Mars was once suitable for sustaining life.
Spirit landed on a flat volcanic flood plain pocked with small craters and strewn with loose rocks. There, the rover found basaltic rocks only slightly altered by exposure to moisture. By June 2004, it had driven to the Columbia Hills, in a quest to find exposed bedrock. Exploring in the hills, Spirit discovered many rocks and soils bearing evidence of extensive exposure to water. In May2009, Spirit became stuck in a patch of fine-grained material. Unable to position its solar array to generate energy, Spirit lost power during the long southern winter, and no further communications were received after 22 March 2010.
Opportunity was sent to a flat region named Meridiani Planum, where a large exposure of the mineral hematite – which often forms in the presence of water - had been discovered. It landed inside a small crater with exposed bedrock in its inner slope. Over the following weeks and months, the rover discovered rock formations that had been saturated with water, and deposited under gently flowing surface water. Opportunity also examined deeper layers of rock inside stadium-size Endurance crater. Opportunity then drove more than 6 km southward to reach Victoria, an even larger and deeper crater. In August 2008, it set off toward 22 km diameter Endeavour crater, arriving in August 2011. Since then, it has been exploring the crater's rim. In July 2014, it broke the record for distance travelled on another world after completing 40 km of driving.
Mars Reconnaissance Orbiter (US)
MRO has been studying the surface, subsurface and atmosphere of Mars in unprecedented detail since November 2006, following a programme of aerobraking to adjust the size and shape of its orbit. The orbiter has sent back more than three times as much data as all other space missions that have travelled beyond the Moon. NASA's Deep Space Network received more than 190 terabytes of data – including more than 70,000 images – from the six science instruments during the mission's first eight years at Mars. Its observations revealed different types of watery environments with extensive mineral deposits - including clays, sulphates and carbonates – that existed early in Mars' history. Radar observations revealed subsurface layering, probably connected to cyclical variations in the tilt of the planet's rotation axis and the shape of its orbit. Radar also revealed a thick deposit of carbon dioxide ice buried in the south polar cap.
Phoenix Mars Lander (US)
In 2001, NASA announced the Mars Scout missions, a new program of low cost missions to Mars. The first of these, known as Phoenix Mars Lander, involved a stationary lander with a robotic digging arm and a suite of science instruments to study the summer environment on the far-northern plains. Phoenix confirmed and examined deposits of underground water ice detected from orbit. It identified calcium carbonate deposits suggesting occasional presence of liquid water and also found soil chemistry with significant implications for life. The lander also witnessed a rare sight on Mars: falling snow. The biggest surprise was the discovery of perchlorate, an oxidising chemical on Earth that is food for some microbes and potentially toxic for others, and which can lower the freezing point of liquid water by tens of degrees. It operated on Mars for two months longer than planned, before the lack of solar energy ended the mission.
Phobos-Grunt (Russia) / Yinghuo-1 (China)
Mars Science Laboratory / Curiosity rover (US)
The Mars Science Laboratory carried Curiosity, the largest roving vehicle ever delivered to the surface of Mars. The primary task of the nuclear-powered rover was to evaluate whether an ancient impact feature, known commonly as Gale Crater, could have once supported life.
The six-wheeled rover is 3m long and 2.8 m wide, with a weight of 899 kg. It was too large for traditional landing techniques, so the final stages of its descent involved a series of retrorockets attached to a "sky crane", from which it was lowered by cords to the surface.
The rover carries 10 scientific instruments. Two of these are attached to a 2.1 m long robotic arm which is also used to scoop up soil and deliver samples to ovens for heating and analysis. A rotary percussive drill can acquire samples of material from up to 5 cm beneath a rock's surface. There is also a rock-zapping laser for analysis of vaporised rocks and another experiment that uses an X-ray beam to identify rock minerals.
The rover has been exploring the rocks around the base of the central mountain in Gale crater and by April 2015 had traversed 10 km. It has found clay minerals that were formed in the presence of water, made the first discovery of organic molecules on Mars and detected unexpected spikes in the amount of atmospheric methane.
Mars Orbiter Mission (Mangalyaan) (India)
India's first Mars mission carries five science instruments to survey the planet, gathering data on the Martian climate and the mineral make-up of its surface. They include a colour imaging camera to return medium resolution pictures, a thermal infrared spectrometer to measure the chemical composition of the surface, and instruments to measure the atmosphere, including a detector to search for methane.
Mars Atmosphere and Volatile EvolutioN (MAVEN) (US)
MAVEN flies in a highly elliptical orbit that ranges from about 150 km to 6000 km above the Martian surface. It carries three instrument packages. The Particles and Fields Package contains six instruments to characterise the solar wind and the ionosphere of the planet. The Remote Sensing Package studies the upper atmosphere and ionosphere. The Neutral Gas and Ion Mass Spectrometer measures the composition and isotopes of atomic particles. The orbiter also relays data from NASA's Curiosity Mars rover to Earth. During a series of deep-dip campaigns MAVEN's lowest altitude is reduced to about 125 km to take measurements throughout the entire upper atmosphere. MAVEN is the second mission in NASA's Scout programme (Phoenix Mars Lander was the first).
ExoMars 2016 / ExoMars Trace Gas Orbiter and Schiaparelli (ESA / Russia)
This mission, a partnership between ESA and Russia's Roscosmos, involves a Trace Gas Orbiter that will survey the global distribution of trace gases in the planet's atmosphere. The orbiter will release an entry, descent, and landing demonstrator module named Schiaparelli, which will make a controlled landing on the planet's surface. Schiaparelli will collect data throughout the descent and will prove key technologies to demonstrate Europe's capability to make a controlled landing on Mars. Once on the surface, Schiaparelli will measure wind speed, humidity, pressure, temperature, atmospheric clarity and electricity in the atmosphere.
The Interior exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) lander is designed to probe Mars' interior with two instruments: a seismometer and heat flow probe. The heat flow probe will penetrate the Martian surface to a depth of 5 m to monitor the planet's temperature. The seismometer will listen for Marsquakes and use that information to map the boundaries between the rock layers inside the planet. InSight is scheduled to launch in May 2018 and land on Mars seven months later.
2020 and beyond
ExoMars 2020 (ESA / Russia)
This mission will deliver a European rover and a Russian surface platform to the surface of Mars. ESA's six-wheeled ExoMars rover is solar powered. It will use a panoramic camera, close-up camera, and drill for rock samples. The drill is designed to extract samples from various depths, down to a maximum of two metres. An infrared spectrometer will characterise the mineralogy in the borehole. Samples will be analysed in its chemical laboratory in a search for organic molecules. The rover will also use ground-penetrating radar to characterise the subsurface and search for water. The rover is expected to travel several kilometres during its mission.
Mars 2020 (US)
In December 2012, NASA announced plans to launch a rover mission, as a follow-up to Curiosity, in 2020. Similar in design to Curiosity, the rover will search for evidence of life and collect samples for possible return to Earth at a later date. The rover will also collect data essential for planning future human expeditions to Mars.
Various space agencies are interested in returning Mars samples to Earth and working toward the long-term goal of landing human explorers on the Red Planet.