   #copyright

Exploration of Mars

2007 Schools Wikipedia Selection. Related subjects: Space transport

   Computer generated image of one of the two Mars Exploration Rovers
   which touched down on Mars in 2004.
   Enlarge
   Computer generated image of one of the two Mars Exploration Rovers
   which touched down on Mars in 2004.

   The exploration of Mars has been an important part of the space
   exploration missions of the Soviet Union (later Russia), the United
   States, Europe, and Japan. Dozens of unmanned spacecraft, including
   orbiters, landers, and rovers, have been launched toward Mars since the
   1960s. These missions were aimed at gathering data and answering
   questions about the red planet and its past that may yield further
   insight into Earth's past, present and future.

   The exploration of Mars has come at a considerable financial cost with
   roughly two-thirds of all spacecraft destined for Mars failing before
   completing or even beginning their missions. Such a high failure rate
   can be attributed to the complexity and large number of variables
   involved in an interplanetary journey, and has led researchers to
   half-jokingly speak of The Great Galactic Ghoul which subsists on a
   diet of Mars probes. This phenomenon is also known widely as the Mars
   Curse.

Questions to explore

   Mars has long been the subject of human fascination. Early telescopic
   observations revealed colour changes on the surface which were
   originally attributed to seasonal vegetation and linear features which
   were ascribed to intelligent design. These early and erroneous
   interpretations led to wide public interest in Mars. Other telescopic
   observations found Mars' two tiny moons, dry channels and depressions,
   polar ice caps, Olympus Mons, the solar system's tallest mountain, and
   Valles Marineris, the solar system's largest canyon system. These
   discoveries have only 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 cold and desert-like surface. Among the questions asked by
   scientists are the following:
    1. How does the composition of Mars differ from the Earth's and how
       have the two planets evolved differently?
    2. How does the composition and state of the interior of Mars differ
       from the Earth's?
    3. Is Mars still geologically active?
    4. What natural resources are available at the surface for future
       human use?
    5. Was there an early dense atmosphere on Mars?
    6. Did Mars once have oceans?
    7. What changes in climate has Mars experienced over its geologic
       history and what caused those changes?
    8. How stable is the climate of Mars today?
    9. Did chemical evolution take place on Mars, leading to the formation
       of prebiotic organic molecules?
   10. Did chemical evolution lead to the formation of replicating
       molecules, i.e. life?
   11. If life once arose, is it to be found anywhere on Mars today?
   12. How did Phobos and Deimos come to be where they are? What geology
       and resources do they possess?

Launch windows

   In order to understand the history of the robotic exploration of Mars
   it is important to note that launch windows occur at intervals of 2.135
   years, i.e. 780 days (the planet's synodic period). Launch windows were
   / will be in:
     * November 1996 to December 1996
     * December 1998 to January 1999
     * April 2001
     * June to July 2003
     * August 2005
     * October 2007
     * December 2009
     * February 2011?

Early flyby probes and orbiters

Early Soviet missions

   The Soviet space program launched two flyby probes towards Mars in
   October 1960, dubbed Mars 1960A and Mars 1960B, but both failed to
   reach Earth orbit. In 1962, three more Soviet probes failed — two in
   Earth orbit ( Mars 1962A and Mars 1962B) and one losing communication
   with Earth en route to Mars ( Mars 1). In 1964, the Soviet Zond 2 was
   another failed attempt to reach Mars. Later in 1974, Mars 5 reached
   Mars and sent back over sixty pictures of the area south of Valles
   Marineris, before a depressurisation ended the mission.

Mariner program

   Taken from Mariner 4, the first close-up image ever taken of Mars shows
   an area about 330 km across by 1200 km from limb to bottom of frame.
   Enlarge
   Taken from Mariner 4, the first close-up image ever taken of Mars shows
   an area about 330 km across by 1200 km from limb to bottom of frame.

   In 1964, NASA's Jet Propulsion Laboratory made two attempts at reaching
   Mars. Mariner 3 and Mariner 4 were identical spacecraft designed to
   carry out the first flybys of Mars. Mariner 3 was launched on November
   5, 1964, but the shroud encasing the spacecraft atop its rocket failed
   to open properly, and it failed to reach Mars. Three weeks later, on
   November 28, 1964, Mariner 4 was launched successfully on an
   eight-month voyage to the red planet.

   Mariner 4 flew past Mars on July 14, 1965, providing the first close-up
   photographs of another planet. The pictures, gradually played back to
   Earth from a small tape recorder on the probe, showed lunar-type impact
   craters. Some of them seemed touched with frost in the chill of a
   Martian evening.

   NASA continued the Mariner program with another pair of Mars flyby
   probes at the next launch window. These probes reached the planet in
   1969. See Mariner 6 and 7 for details. During the following launch
   window the Mariner program again suffered the loss of one of a pair of
   probes. Mariner 9 successfully entered orbit about Mars, after the
   launch time failure of its sister ship, Mariner 8. When Mariner 9
   reached Mars, it and two Soviet orbiters ( Mars 2 and Mars 3, see Mars
   probe program below) found that a planet-wide dust storm was in
   progress. The mission controllers used the time spent waiting for the
   storm to clear to have the probe rendezvous with, and photograph,
   Phobos. When the storm cleared sufficiently for Mars' surface to be
   photographed by Mariner 9, the pictures returned represented a
   substantial advance over previous missions. These pictures were the
   first to offer evidence that liquid water might at one time have flowed
   on the planetary surface.

Landers and later missions

Mars probe program

   In 1969, the Soviet Union prepared an ambitious 5-ton orbiter called
   M-69. Two copies of the probe were both lost in launch mishaps
   involving the new and powerful Proton rocket.

   In 1971, shortly after Cosmos 419 failed to launch, the Soviet Union
   successfully sent Mars 2 and Mars 3, nearly a decade after the launch
   of Mars 1, all part of the Mars probe program. The Mars 2 and 3 probes
   each carried a lander, both arriving on Mars in 1971. The Mars 2 lander
   entered Mars' atmosphere at too steep an angle, causing it to crash,
   and the Mars 3 lander functioned for only 20 seconds after landing.
   They were the first human artifacts to touch down on Mars.

   In 1973, the Soviet Union sent four more probes to Mars: the Mars 4 and
   Mars 5 orbiters and the Mars 6 and Mars 7 flyby/lander combinations. Of
   the four, only Mars 5 succeeded; it transmitted 60 images before
   suffering a transmitter failure. Mars 6's lander transmitted data
   during descent but failed on impact. Mars 4 and 7 both missed the
   planet.

Viking program

   Viking Lander 1 landing site (click image for detailed description).
   Enlarge
   Viking Lander 1 landing site (click image for detailed description).

   In 1976 the two Viking probes entered orbit about Mars and each
   released a lander module that made a successful soft landing on the
   planet's surface. The two missions returned the first colour pictures
   and extensive scientific information. Measured temperatures at the
   landing sites ranged from 150 to 250 K, with a variation over a given
   day of 35 to 50 K. Seasonal dust storms, pressure changes, and movement
   of atmospheric gases between the polar caps were observed. A biology
   experiment produced possible evidence of life, but it was not
   corroborated by other on-board experiments. Most scientists believe
   there currently is no life on Mars.

   While searching for a suitable landing spot for Viking 2's lander, the
   Viking 1 orbiter photographed the landform that constitutes the
   so-called " Face on Mars" on July 25, 1976.

   The Viking program was a descendant of the cancelled Voyager program,
   whose name was later reused for a pair of outer solar system probes.

Phobos program

   The Soviet Union went to Mars again in 1988 with the Phobos 1 and 2
   probes to study the planet and its moons Phobos and Deimos. Phobos 1
   lost contact on the way to Mars. Phobos 2 successfully photographed
   Mars and Phobos, including several striking images of Moon and Planet
   in the same frame; however, it failed just before it was set to release
   two landers on Phobos' surface.

Mars Global Surveyor

   This image from Mars Global Surveyor spans a region about 1500 meters
   across. Gullies, similar to those formed on Earth, are visible from
   Newton Basin in Sirenum Terra (NASA).
   Enlarge
   This image from Mars Global Surveyor spans a region about 1500 meters
   across. Gullies, similar to those formed on Earth, are visible from
   Newton Basin in Sirenum Terra (NASA).

   After the 1992 failure of NASA's Mars Observer orbiter, NASA retooled
   and launched Mars Global Surveyor. This mission was the first
   successful United States mission, and the first fully successful
   mission overall, to the red planet in two decades when it launched
   November 7, 1996, and entered orbit on September 12, 1997. After a year
   and a half trimming its orbit from a looping ellipse to a circular
   track around the planet, the spacecraft began its primary mapping
   mission in March 1999. It has observed the planet from a low-altitude,
   nearly polar orbit over the course of one complete Martian year, the
   equivalent of nearly two Earth years. Mars Global Surveyor completed
   its primary mission on January 31, 2001, and is now in an extended
   mission phase.

   The mission has studied the entire Martian surface, atmosphere, and
   interior, and has returned more data about the red planet than all
   other Mars missions combined. These valuable data are archived and
   available publicly.

   Among key scientific findings so far, Global Surveyor has taken
   pictures of gullies and debris flow features that suggest there may be
   current sources of liquid water, similar to an aquifer, at or near the
   surface of the planet. Similar channels on Earth are formed by flowing
   water, but on Mars the temperature is normally too cold and the
   atmosphere too thin to sustain liquid water. Nevertheless, many
   scientists hypothesize that liquid groundwater can sometimes surface on
   Mars, erode gullies and channels, and pool at the bottom before
   freezing and evaporating.

   Magnetometer readings show that the planet's magnetic field is not
   globally generated in the planet's core, but is localized in particular
   areas of the crust. New temperature data and closeup images of the
   Martian moon Phobos show its surface is composed of powdery material at
   least 1 metre (3 feet) thick, caused by millions of years of meteoroid
   impacts. Data from the spacecraft's laser altimeter have given
   scientists their first 3-D views of Mars' north polar ice cap.

   On the 5th of November 2006 the Mars Global Surveyor lost contact with
   earth. On Nov. 2, MGS mangers sent commands for the spacecraft to
   adjust the position of one of its solar power arrays to better track
   the sun. Returning data indicated a problem with the motor that moves
   the array, so a backup motor and control circuitry were switched on.

   No signal was received on Nov. 3 and 4, but a weak signal was received
   on Nov. 5, suggesting the spacecraft had switched to a safe mode and
   was awaiting further instructions from Earth. The signal cut out
   completely later that day and nothing has been heard since.

   Engineers think the spacecraft has performed a programmed maneuver in
   which it turns its solar arrays toward the sun to maintain its power
   supply. When it does this, it also reorients its entire body in the
   same direction, thus making communication with Earth less effective.

   MGS launched towards Mars just over 10 years ago, on Nov. 7, 1996, and
   marked NASA's first successful return to the red planet in two decades.
   The spacecraft was originally tasked with examining Mars for a full
   Martian year, roughly two Earth years. Operations were slated to end in
   early 2001, but like the two Mars rovers, Opportunity and Spirit, MGS
   was continued to perform so admirably that its mission was repeatedly
   extended, most recently on Oct. 1 of this year.

   Since its mission formally began in 1999, MGS has returned a wealth of
   data about the red planet. The spacecraft has tracked the evolution of
   a dust storm, gathered information on the Martian landscape, found
   compelling evidence of gullies apparently carved by flowing water, and
   revealed the infamous "face on Mars," originally photographed in 1976
   by Viking 1, to be nothing more than a natural landscape. It has also
   taken tens of thousands of high-resolution images of Mars and performed
   the first three-dimensional mapping of the planet's North Pole.

   It’s important to recognize that MGS was on its third extended mission.
   And through all the years of scanning Mars, MGS also supported the Mars
   Reconnaissance Orbiter’s lengthy aerobraking at the planet by watching
   for martian dust storms that influence Mars’ upper atmosphere.

   There’s a feeling that maybe the well-used MGS felt it was time to sign
   off.

   On the 10th anniversary of MGS in space—November 7—that’s the same day
   that MRO cranked up its primary science tasks.

Mars Pathfinder

   "Ares Vallis" as photographed by Mars Pathfinder (click image for
   detailed description).
   Enlarge
   "Ares Vallis" as photographed by Mars Pathfinder (click image for
   detailed description).

   The Mars Pathfinder spacecraft, launched one month after Global
   Surveyor, landed on July 4, 1997. Its landing site was an ancient flood
   plain in Mars' northern hemisphere called Ares Vallis, which is among
   the rockiest parts of Mars. It carried a tiny remote-controlled rover
   called Sojourner, which traveled a few meters around the landing site,
   exploring the conditions and sampling rocks around it. Newspapers
   around the world carried images of the lander dispatching the rover to
   explore the surface of Mars in a way achieved only twice previously by
   the Russian Lunokhod rovers on the moon 30 years before (the Lunokhods
   covered considerably greater distances also: 11km and 37km,
   repectively).

   Until the final data transmission on September 27, 1997, Mars
   Pathfinder returned 16,500 images from the lander and 550 images from
   the rover, as well as more than 15 chemical analyses of rocks and soil
   and extensive data on winds and other weather factors. Findings from
   the investigations carried out by scientific instruments on both the
   lander and the rover suggest that Mars was at one time in its past warm
   and wet, with water existing in its liquid state and a thicker
   atmosphere. The mission website was the most heavily-trafficked up to
   that time.

Spate of failures

   Following the success of Global Surveyor and Pathfinder, another spate
   of failures occurred in 1998 and 1999, with the Japanese Nozomi orbiter
   and NASA's Mars Climate Orbiter, Mars Polar Lander, and Deep Space 2
   penetrators all suffering various fatal errors. Mars Climate Orbiter is
   infamous for Lockheed Martin engineers mixing up the usage of imperial
   units with metric units, causing the orbiter to burn up while entering
   Mars' atmosphere.

Mars Odyssey

   In 2001 the run of bad luck ended when NASA's Mars Odyssey orbiter
   arrived. Its mission is to use spectrometers and imagers to hunt for
   evidence of past or present water and volcanic activity on Mars. In
   2002, it was announced that the probe's gamma ray spectrometer and
   neutron spectrometer had detected large amounts of hydrogen, indicating
   that there are vast deposits of water ice in the upper three meters of
   Mars' soil within 60° latitude of the south pole.

Mars Express and Beagle 2

   On June 2, 2003, the European Space Agency's Mars Express set off from
   Baikonur Cosmodrome to Mars. The Mars Express craft consists of the
   Mars Express Orbiter and the lander Beagle 2. Although the landing
   probe was not designed to move, it carried a digging device and the
   smallest mass spectrometer created to date, as well as a range of other
   devices, on a robotic arm in order to accurately analyse soil beneath
   the dusty surface.

   The orbiter entered Mars orbit on December 25, 2003, and Beagle 2
   entered Mars' atmosphere the same day. However, attempts to contact the
   lander failed. Communications attempts continued throughout January,
   but Beagle 2 was declared lost in mid-February, and a joint inquiry was
   launched by the UK and ESA. Nevertheless, Mars Express Orbiter
   confirmed the presence of water ice and carbon dioxide ice at the
   planet's south pole. NASA had previously confirmed their presence at
   the north pole of Mars.

Mars Exploration Rovers

   Shortly after the launch of Mars Express, NASA sent a pair of twin
   rovers toward the planet as part of the Mars Exploration Rover Mission.
   On 10 June 2003, NASA's MER-A (Spirit) Mars Exploration Rover was
   launched. It successfully landed in Gusev Crater (believed once to have
   been a crater lake) on 3 January 2004. It examined rock and soil for
   evidence of the area's history of water. On July 7, 2003, a second
   rover, MER-B (Opportunity) was launched. It landed on 24 January 2004
   in Meridiani Planum (where there are large deposits of hematite,
   indicating the presence of past water) to carry out similar geological
   work.
   Part of a 360 degree panorama photo of the Gusev crater landing site,
   taken by NASA's Spirit Rover in 2004
   Enlarge
   Part of a 360 degree panorama photo of the Gusev crater landing site,
   taken by NASA's Spirit Rover in 2004

   Despite a temporary loss of communication with the Spirit Rover (caused
   by too many files being stored in its flash memory ) delaying
   exploration for several days, both rovers eventually began exploring
   their landing sites. The rover Opportunity landed in a particularly
   interesting spot, a crater with bedrock outcroppings. In fast
   succession mission team members announced on 2 March that data returned
   from the rover showed that these rocks were once "drenched in water",
   and on 23 March that it was concluded that they were laid down
   underwater in a salty sea. This represented the first strong direct
   evidence for liquid water being on Mars at some time in the past.

   Towards the end of July 2005, it was reported by the Sunday Times that
   the rovers may have carried the bacteria Bacillus safensis to Mars.
   According to one NASA microbiologist, this bacteria could survive both
   the trip and conditions on Mars. A book containing this claim, Out of
   Eden by Alan Burdick, is due to be published in the United Kingdom.
   Despite efforts to sterilise both landers, neither could be assured to
   be completely sterile.

   As of November 2006, both rovers are still healthy, though starting to
   show their ages in ways that require occasional intervention from
   Earth, and discovering new things, including Heat Shield Rock, the
   first meteorite to be discovered on another planet.

Mars Reconnaissance Orbiter

   Mars Reconnaissance Orbiter is a multipurpose spacecraft designed to
   conduct reconnaissance and exploration of Mars from orbit. The $720
   million USD spacecraft was built by Lockheed Martin under the
   supervision of the Jet Propulsion Laboratory, launched August 12, 2005,
   and attained Martian orbit on March 10, 2006.

   The MRO contains a host of scientific instruments such as the HiRISE
   camera, CRISM, and SHARAD. The HiRISE camera will be used to analyze
   Martian landforms, whereas CRISM and SHARAD will detect water, ice, and
   minerals on and below the surface. Additionally, MRO will pave the way
   for upcoming generations of spacecraft through daily monitoring of
   Martian weather and surface conditions, searching for future landing
   sites, and testing a new telecommunications system that will enable the
   orbiter to send and receive information at an unprecedented bitrate.
   Data transfer to and from the spacecraft will occur faster than all
   previous interplanetary missions combined and allowing it to serve as
   an important relay satellite for future missions.

Future Missions

   The next mission to Mars is the Phoenix Mars lander, expected to launch
   in 2007.

   It should be followed by a (or a couple of) more capable rover(s) in
   2009 or 2011 and by the European ExoMars mission in 2014. The Exomars
   mission should obtain soil samples from up to 2 meters depth and make
   an extensive search for organic and biochemical substances.

   A second Scout mission, Mars 2011 should also be selected soon for
   2011.

   In addition, NASA plans to launch a proposed rover, the Astrobiology
   Field Laboratory in 2016.

   Russia is still planning to launch its Phobos-Grunt probe in 2009.

Mars Curse

   The high failure rate of NASA and other governmental agencies in their
   attempts to explore Mars has become known as the Mars Curse. See below
   for a full list of launch attempts to Mars.

   By the spring of 2006, of 37 launch attempts to reach the planet, only
   18 have succeeded. Eleven of the missions included attempts to land on
   the surface, but only six transmitted data once on the surface, and of
   those only one was non-American (Russian), which lost contact within 20
   seconds of landing. Some suggest, mostly in jest, that there is
   actually some force trying to prevent or punish the exploration of
   Mars. The Galactic Ghoul is a fictional space monster that consumes
   Mars probes, a term coined in 1997 by Time Magazine journalist Donald
   Neff.

               Failed & Cancelled missions to the Planet Mars
   Failed: Marsnik program | Sputnik 22 | Mars 1 | Sputnik 24 | Mariner 3
   | Zond 2 | Mars 1969A | Mars 1969B | Mariner 8 | Cosmos 419 | Mars 6 |
     Mars 7 | Phobos 1 | Mars Observer | Mars 96 | Nozomi | Mars Climate
            Orbiter | Mars Polar Lander | Deep Space 2 | Beagle 2
      Cancelled: Voyager | Mars Surveyor 2001 Lander | NetLander | Mars
                         Telecommunications Orbiter

Manned missions

   Many people have long advocated a manned mission to Mars as the next
   logical step for a manned space program after lunar exploration. Aside
   from the prestige such a mission would bring, advocates argue that
   humans would be easily able to outperform robotic explorers, justifying
   the expenses. Eugene F. Lally of Caltech for NASA's Jet Propulsion
   Laboratory designed manned Mars missions and presented them at American
   Rocket Society conventions as early as 1959. In another paper Lally
   proposed a simulated gravity concept that would protect the astronauts
   during the prolonged weightlessness of the flight to Mars. The paper
   titled "To Spin or Not to Spin" proposed separating two main segments
   of the spacecraft connected by cables and spun up to simulate gravity.
   In the centre of rotation Lally placed an all-optical guidance module
   to provide real time onboard navigation to the astronauts, this paper
   was titled "Mosaic Guidance for Interplanetary Travel" 1961.

   Because of the distance between Mars and Earth, the mission would be
   much more risky and more expensive than past manned flights to the
   Moon. Supplies and fuel would have to be prepared for a 2-3 year round
   trip and the spacecraft would have to be designed with at least partial
   shielding from intense solar radiation. A proposal called Mars Direct,
   advocated by Robert Zubrin of the Mars Society, is believed by many to
   be the most practical and affordable plan for a manned Mars mission. A
   ground-based biomedical experiment Mars-500 simulating manned flight to
   Mars will start in 2007 in Russia.

   United States President George W. Bush announced an initiative of
   manned space exploration on January 14, 2004, known as the Vision for
   Space Exploration. It includes a manned return to the moon by 2015 at
   the earliest, and suggests that manned missions to Mars may become a
   possibility at some point in the future. The European Space Agency has
   the long-term vision of sending a human mission to Mars by 2030, the
   Aurora Programme.

   Many scientists have argued that attempting manned flight to Mars would
   actually be counterproductive for science. For example, in 2004 the
   American Physical Society, the world's second-largest organization of
   physicists, stated that "shifting NASA priorities toward risky,
   expensive missions to the moon and Mars will mean neglecting the most
   promising space science efforts" . Moreover, given the rapidly
   advancing capabilities of robotic explorers, including their
   demonstrated ability to carry out continuous observations during
   multi-year sojourns on the hostile Martian surface, it is not obvious
   that human explorers would actually return more science data for the
   dollar.

   In the even longer term (centuries hence), some scientists believe Mars
   to be a good candidate for terraforming and human colonization, though
   other prominent skeptics (such as Robert L. Park) dispute the
   practicality of both. Many scientists have argued that if life is found
   on Mars, all human activities on the planet should be carried out with
   the goal of preservation in mind. Others argue that the presence of
   life on Mars would imply that life is prevalent throughout the
   universe; decreasing the relative importance of Martian microbes.

Timeline of Mars exploration

   Dates listed are spacecraft launch dates.
   Mission Launch Termination Objective Result
   Union of Soviet Socialist Republics Marsnik 1 (Mars 1960A) 10 October
   1960 10 October 1960 Flyby Launch failure
   Union of Soviet Socialist Republics Marsnik 2 (Mars 1960B) 14 October
   1960 14 October 1960 Flyby Launch failure
   Union of Soviet Socialist Republics Sputnik 22 (Mars 1962A) 24 October
   1962 24 October 1962 Flyby Broke up shortly after launch
   Union of Soviet Socialist Republics Mars 1 1 November 1962 21 March
   1963 Flyby Some data collected, but lost contact before reaching Mars
   Union of Soviet Socialist Republics Sputnik 24 (Mars 1962B) 4 November
   1962 January 1963 Lander Failed to leave Earth's orbit
   United States Mariner 3 5 November 1964 5 November 1964 Flyby Failure
   during launch ruined trajectory. Currently in solar orbit.
   Mariner 4 28 November 1964 21 December 1967 Flyby Success
   Union of Soviet Socialist Republics Zond 2 30 November 1964 May 1965
   Flyby Lost contact
   Mariner 6 25 February 1969 August 1969 Flyby Success
   Mariner 7 27 March 1969 August 1969 Flyby Success
   Union of Soviet Socialist Republics Mars 1969A 27 March 1969 27 March
   1969 Orbiter Launch failure
   Union of Soviet Socialist Republics Mars 1969B 2 April 1969 2 April
   1969 Orbiter Launch failure
   Mission Launch Termination Objective Result
   Mariner 8 8 May 1971 8 May 1971 Orbiter Launch failure
   Union of Soviet Socialist Republics Cosmos 419 10 May 1971 12 May 1971
   Orbiter Launch failure
   Union of Soviet Socialist Republics Mars 2 19 May 1971 22 August 1972
   Orbiter Success
   27 November 1971 Rover Crash landed on surface of Mars
   Union of Soviet Socialist Republics Mars 3 28 May 1971 22 August 1972
   Orbiter Success
   2 December 1971 Rover Landed softly, but ceased transmission within
   seconds
   Mariner 9 30 May 1971 May 1972 Orbiter Success
   Union of Soviet Socialist Republics Mars 4 21 July 1973 February 1974
   Orbiter Did not enter orbit, but made a close flyby
   Union of Soviet Socialist Republics Mars 5 25 July 1973 21 February
   1974 Orbiter Partial success. Entered orbit, and returned data, but
   failed within 9 days
   Union of Soviet Socialist Republics Mars 6 5 August 1973 12 March 1974
   Lander Partial success. Data returned during descent, but not after
   landing on Mars
   Union of Soviet Socialist Republics Mars 7 9 August 1973 9 March 1974
   Lander Landing probe separated prematurely; entered heliocentric orbit.
   Viking 1 20 August 1975 17 August 1980 Orbiter Success
   13 November 1982 Lander Success
   Viking 2 9 September 1975 25 July 1978 Orbiter Success
   11 April 1980 Lander Success
   Union of Soviet Socialist Republics Phobos 1 7 July 1988 2 September
   1988 Orbiter Contact lost en route to Mars
   Phobos lander Not deployed
   Union of Soviet Socialist Republics Phobos 2 12 July 1988 27 March 1989
   Orbiter Partial success: entered orbit and returned some data. Contact
   lost just before deployment of landers
   2 Phobos landers Not deployed
   Mission Launch Termination Objective Result
   Mars Observer 25 September 1992 21 August 1993 Orbiter Lost contact
   just before arrival
   Mars Global Surveyor 7 November 1996 Currently operational Orbiter
   Success
   Mars 96 16 November 1996 17 November 1996 Orbiter / landers Launch
   failure
   Mars Pathfinder 4 December 1996 27 September 1997 Lander / rover
   Success
   Nozomi (Planet-B) 3 July 1998 9 December 2003 Orbiter Complications en
   route; Never entered orbit
   Mars Climate Orbiter 11 December 1998 23 September 1999 Orbiter Crash
   landed on surface due to metric-imperial mix-up
   Mars Polar Lander 3 January 1999 3 December 1999 Lander Lost contact
   just before arrival
   Deep Space 2 (DS2) Landers
   Mission Launch Termination Objective Result
   2001 Mars Odyssey 7 April 2001 Currently operational Orbiter Success
   Mars Express Orbiter 2 June 2003 Currently operational Orbiter Success
   Beagle 2 25 December 2003 Lander Lost contact upon landing
   Spirit rover 10 June 2003 Currently operational Rover Success
   Opportunity rover 7 July 2003 Currently operational Rover Success
   Rosetta 2 March 2004 Currently operational Flyby Currently en route
   Mars Reconnaissance Orbiter 12 August 2005 Currently operational
   Orbiter Completed Aerobraking. Initiated science mission Nov 2006.

Planned missions

     * Phoenix - August 2007 - Small Mars scout lander ( NASA)
     * Phobos-Grunt - October 2009 - Mars orbiter and Phobos sample return
       ( RKA)
     * Mars Science Laboratory - 2009 - Mars Rover ( NASA)
     * Beagle 2: Evolution - 2009 - Mars Lander (ESA)

     * Mars 2011 - 2011 - Mars Scout mission ( NASA)
     * Mars Science and Telecommunications Orbiter - 2011 or 2013 - Mars
       Orbiter ( NASA)
     * ExoMars - 2014 - Mars Rover (ESA)
     * Astrobiology Field Laboratory - 2016 - Mars Rover - proposed (
       NASA)
     * Mars Sample Return Mission - delayed until at least 2016, more
       probably to 2024 - planned mission by ESA and NASA as part of the
       Aurora Programme

Cancelled missions

     * Voyager - 1970s - Two orbiters and two landers, launched by a
       single Saturn V rocket.
     * Mars Surveyor 2001 Lander - October 2001 - Mars lander to be aboard
       2001 Mars Odyssey
     * NetLander - 2007 or 2009 - Mars netlanders
     * Mars Telecommunications Orbiter - September 2009 - Mars orbiter for
       telecommunications

   Retrieved from " http://en.wikipedia.org/wiki/Exploration_of_Mars"
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   with only minor checks and changes (see www.wikipedia.org for details
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