How many active or inactive artificial satellites are in Mars orbit?

Question

I just read in the BBC news that four nations have placed satellites in Mars orbit. How many active or inactive artificial satellites are there in orbit around Mars (2014)?

Answer 1

There are currently 14-16 known artificial satellites in Mars orbit (8 active):

• Mars-2, launched 1971 May 19, USSR, inactive
• Mars-3, launched 1971 May 28, USSR, inactive
• Mariner 9, launched 1971 May 30, USA, inactive, estimated to deorbit October 2022 or later
• Mars-5, launched 1973 July 25, USSR, inactive
• Viking 1, launched 1975 August 20, USA, inactive, estimated to deorbit 2019 or later
• Viking 2, launched 1975 September 9, USA, inactive
• Phobos-2, launched 1988 July 12, USSR, inactive
• Mars Global Surveyor, launched 1996 November 7, USA, inactive, estimated to deorbit 2047 or later
• 2001 Mars Odyssey, launched 2001 April 7, USA, active
• Mars Express, launched 2003 June 2, European Space Agency (launched by Russia), active
• Mars Reconnaissance Orbiter, launched 2005 August 12, USA, active
• Mars Orbiter Mission (MOM) or Mangalyaan, launched 2013 November 5, India, active
• Mars Atmosphere and Volatile Evolution (MAVEN), launched 2013 November 18, USA, active
• ExoMars Trace Gas Orbiter, launched 2016 March 14, ESA and Russia, active
• Emirates Mars Mission aka Hope/Al-Amal, launched 2020 July 19, UAE and Japan, active
• Tianwen-1, launched 2020 July 23, China, active

One small clarification: Mark Adler has pointed out that since we do not actively track the inactive orbiters, they may not actually be in orbit. They are generally expected to be in orbit longer, however.

Source:

• A complete list of the world's launch attempts in the direction of Mars - Russian Space Web