About sixty percent of all spacecraft sent to Mars never finished the job
The first spacecraft to land softly on Mars, the Soviet Mars 3 in December 1971, went silent after 14.5 seconds. Britain's Beagle 2 vanished in 2003 and was spotted twelve years later from orbit, safely down but with its solar panels only partly unfolded. Getting to Mars has proved brutally hard, with roughly three in five missions failing.
Timing is dictated by orbital mechanics. The cheapest launch windows open about every 780 days, and the energy needed also rises and falls on a cycle of roughly 16 years. The Soviet Union tried first, launching nine probes toward Mars between 1960 and 1969; every one failed, some on the launch pad's doorstep and others in deep space. Mars 1 got closest in that era, reaching interplanetary space in 1962 and sending back 61 radio sessions before its antenna pointing system failed more than 100 million kilometres from Earth.
America's Mariner 4 made the first successful flyby in July 1965, and Mariner 9 became the first probe to orbit another planet in November 1971. Days later the Soviet Mars 2 lander crashed, becoming the first human-made object on the Martian surface, before Mars 3 managed its brief soft landing. The two NASA Viking landers of 1976 sent home the first colour panoramas and lasted years.
Later missions filled in the picture. The Odyssey orbiter detected hydrogen in the top metre or so of soil in 2001, pointing to large deposits of buried ice, and in 2008 the Phoenix lander scraped into the ground near the north pole and confirmed water ice directly. Europe's Mars Express spotted methane, a possible sign of biology, and auroras. The twin rovers Spirit and Opportunity, landed in 2004, found conclusive evidence that liquid water had once existed at both sites, and outlived their planned missions by years, helped by gusts and dust devils that occasionally swept their solar panels clean. Spirit ended its career in 2010, stuck in sand and unable to tilt toward the Sun.
India joined the club in 2014, becoming the first country to reach Mars orbit on its first try. NASA's Curiosity and Perseverance are still driving today, and Perseverance's companion helicopter Ingenuity scouted ahead until 2024. Six orbiters, from American, European, Emirati and Chinese agencies, keep watch overhead.
Source: Exploration of Mars
