List of Mars orbiters

Artist's rendering of NASA's 2001 Mars Odyssey orbiting Mars

The following table is a list of Mars orbiters, consisting of space probes which were launched from Earth and are currently orbiting Mars. As of November 2015, there are thirteen known artificial satellites in Mars' orbit, five of which are actively collecting data.

History

20th century

Soviet stamp endorsing Mars 2

The Soviets' Mars program and NASA's Mariner program became the two first successful space programs that intended to explore Mars through orbiters. Mars 2, Mars 3 and Mariner 9 were all launched into space in May 1971, and all entered Mars’ orbit that same year. NASA's Mariner 9 reached the planet's orbit first on November 14, narrowly beating the Soviet's spacecraft amid the space race, and subsequently became the first spacecraft to orbit another planet.

Contact with all eight Mars orbiters launched during the 20th century has been lost. NASA's four spacecraft are conjectured to remain in Mars' orbit. Mariner 9, Viking 1 and Viking 2 are expected to lower down into the Martian atmosphere by 2022 and either burn up or crash into the planet's surface. Mars Global Surveyor is expected to crash onto the surface of the planet by 2047. The fate of the Soviet's three Mars program orbiters and Phobos 2 remains unclear, but they are still presumed to be in orbit.

21st century

Mars Express as seen by NASA's Mars Global Surveyor

2001 Mars Odyssey was launched April 7, 2001 on a Delta II rocket and currently holds the record for the longest-surviving continually active spacecraft in orbit around a planet other than Earth at .

In 2003, the European Space Agency (ESA) attempted their first planetary mission by launching Mars Express to conduct reconnaissance and exploration of Mars from orbit. On 12 August 2005, NASA launched Mars Reconnaissance Orbiter (MRO). As MRO entered orbit in 2006, it joined three other active spacecraft which were in Mars' orbit: Mars Global Surveyor (MGS), Mars Express, and 2001 Mars Odyssey; at the time, this set a record for the most operational spacecraft in the immediate vicinity of Mars. MGS has since ceased to function.

On September 24, 2014, Mangalyaan, launched by the Indian Space Research Organisation, reached Mars orbit. ISRO launched the orbiter on November 5, 2013, with the aim of analyzing the Martian atmosphere and topography. The mission is the first successful Asian interplanetary mission in history. Ten days after ISRO's launch, NASA launched their seventh Mars orbiter MAVEN to study the Martian atmosphere. Its goals include determining how the planet's atmosphere and water, presumed to have once been substantial, were lost over time.

Legend

Colors
	Destroyed
	Loss of contact
	Operational

Table of objects

Artificial object	Agency	Launch date	Entered orbit	Days active	Image
Mars 2	Lavochkin	19 May 1971	27 November 1971	7001100000000000000♠ days
Mars 3	Lavochkin	28 May 1971	2 December 1971	7001110000000000000♠ days
Mariner 9	NASA	30 May 1971	14 November 1971	7000900000000000000♠ days
Mars 5	Lavochkin	25 July 1973	12 February 1974	7001130000000000000♠ days
Viking 1	NASA	20 August 1975	19 June 1976	7000500000000000000♠ days
Viking 2	NASA	9 September 1975	7 August 1976	7000600000000000000♠ days
Phobos 2	IKI	12 July 1988	29 January 1989	7001120000000000000♠ days
Mars Global Surveyor	NASA	7 November 1996	12 September 1997	7000400000000000000♠ days
2001 Mars Odyssey	NASA	7 April 2001	24 October 2001	7000100000000000000♠ days
Mars Express	ESA	2 June 2003	25 December 2003	7000200000000000000♠ days
Mars Reconnaissance Orbiter	NASA	12 August 2005	10 March 2006	7000300000000000000♠ days
Mangalyaan	ISRO	5 November 2013	24 September 2014	7000800000000000000♠ days
MAVEN	NASA	18 November 2013	22 September 2014	7000700000000000000♠ days
ExoMars Trace Gas Orbiter	ESA Roscosmos	14 March 2016	19 October 2016 (planned)

See also

• Exploration of Mars
• List of missions to Mars
• Timeline of artificial satellites and space probes
• Timeline of planetary exploration
• Unmanned space missions