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People have been exploring the surface of Mars for over 50 years. According to the United Nations Office for Outer Space Affairs, nations have sent 18 human-made objects to Mars over 14 separate missions. Many of these missions are still ongoing, but over the decades of Martian exploration, humankind has left behind many pieces of debris on the planet’s surface.
I am a postdoctoral research fellow who studies ways to track Mars and Moon rovers. In mid-August 2022, NASA confirmed that the Mars rover Perseverance had spotted a piece of trash jettisoned during its landing, this time a tangled mess of netting. And this is not the first time scientists have found trash on Mars. That’s because there is a lot there.
All spacecraft that land on Mars eject equipment – like this protective shell – on their way to the Martian surface.
NASA/JPL-Caltech
Where does the debris come from?
Debris on Mars comes from three main sources: discarded hardware, inactive spacecraft and crashed spacecraft.
Every mission to the Martian surface requires a module that protects the spacecraft. This module includes a heat shield for when the craft passes through the planet’s atmosphere and a parachute and landing hardware so that it can land softly.
The craft discards pieces of the module as it descends, and these pieces can land in different locations on the planet’s surface – there may be a lower heat shield in one place and a parachute in another. When this debris crashes to the ground, it can break into smaller pieces, as happened during the Perseverance rover landing in 2021. These small pieces can then get blown around because of Martian winds.
The Perseverance rover came across this piece of netting on July 12, 2022, more than a year after landing on Mars.
NASA/JPL-Caltech
A lot of small, windblown trash has been found over the years – like the netting material found recently. Earlier in the year, on June 13, 2022, Perseverance rover spotted a large, shiny thermal blanket wedged in some rocks 1.25 miles (2 km) from where the rover landed. Both Curiosity in 2012 and Opportunity in 2005 also came across debris from their landing vehicles.
The European Space Agency’s Schiaparelli lander crashed onto the surface of Mars in 2016, as seen in these photos of the crash site captured by NASA’s Mars Reconnaissance Orbiter.
NASA/JPL-Caltech/Univ. of Arizona
Dead and crashed spacecraft
The nine inactive spacecraft on the surface of Mars make up the next type of debris. These craft are the Mars 3 lander, Mars 6 lander, Viking 1 lander, Viking 2 lander, the Sojourner rover, the formerly lost Beagle 2 lander, the Phoenix lander, the Spirit rover and the most recently deceased spacecraft, the Opportunity rover. Mostly intact, these might be better considered historical relics than…