Mars Reconnaissance Orbiter — Active mission (science.nasa.gov, page updated 2026-09-03). There since 2006-03-10.
2001 Mars Odyssey — Active mission (science.nasa.gov, page updated 2026-06-22) — the longest-serving spacecraft at another planet. NASA put its remaining propellant at about 4 kg in 2023. There since 2001-10-24.
Mars Express — Operating; funded to the end of 2026 with an extension to 2029 requested (ESA, EPSC 2026 abstract, September 2026). There since 2003-12-25.
ExoMars Trace Gas Orbiter — Operating; spacecraft health nominal (ESA, EPSC 2026 abstract, September 2026). There since 2016-10-19.
Hope (Emirates Mars Mission) — Operating; in an extended phase through 2028 (UAE Space Agency, quoted by NYU Abu Dhabi, June 2026). There since 2021-02-09.