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 man-made objects to Mars in 14 separate missions. Many of these missions are still ongoing, but over decades of Mars exploration, humanity has left behind a lot of debris on the planet’s surface.
I am a postdoctoral researcher studying ways to track Martian and Lunar rovers. In mid-August 2022, NASA confirmed that the Mars Perseverance rover had spotted a piece of trash dropped during its landing, this time a mess of tangled nets. And this isn’t the first time scientists have found trash on Mars. It’s because there are so many.
Where does the debris come from?
Debris on Mars comes from three main sources: scrapped hardware, inactive spacecraft, and crashed spacecraft.
Each mission to the Martian surface requires a module that protects the spacecraft. This module includes a heat shield as the craft passes through the planet’s atmosphere and a parachute and landing gear so it can land smoothly.
The craft throws off pieces of the module as it descends, and these pieces may land in different places on the planet’s surface – there may be a lower heat shield in one place and a parachute in another . When this debris hits the ground, it can shatter into smaller pieces, as happened when the Perseverance rover landed in 2021. These small pieces can then be blown away by Martian winds.
Lots of small windblown rubbish has been found over the years, such as the net found recently. Earlier in the year, on June 13, 2022, the Perseverance rover spotted a large, bright thermal blanket stuck in rocks 2 km from where the rover landed. Curiosity in 2012 and Opportunity in 2005 also encountered debris from their landing vehicles.
Dead and crashed spaceship
The next type of debris is the nine inactive spacecraft on the surface of Mars. These craft are the Mars 3 lander, the Mars 6 lander, the Viking 1 lander, the Viking 2 lander, the Sojourner rover, the formerly lost Beagle 2 lander, the Phoenix lander, the Spirit rover and the ship most recently deceased spacecraft, the Opportunity rover. For the most part intact, these might be better considered historical relics than garbage.
Wear takes its toll on everything on the Martian surface. Parts of Curiosity’s aluminum wheels have broken off and are presumably scattered along the rover’s track. Some of the litter is useful, with Perseverance dropping a drill bit on the surface in July 2021, allowing it to swap in a pristine new bit so that he can continue to collect samples.
Another major source of waste is crashed spaceships and their pieces. At least two spacecraft crashed and four others lost contact before or shortly after landing. Descending safely to the planet’s surface is the hardest part of any Mars landing mission – and it doesn’t always end well.
When you add up the mass of all spacecraft that have ever been sent to Mars, you get about 22,000 pounds (9,979 kilograms). Subtract the weight of the craft currently operational on the surface – 6,306 pounds (2,860 kilograms) – and you’re left with 15,694 pounds (7,119 kilograms) of human debris on Mars.
Why is waste important?
Today, the main concern of scientists about waste on Mars is the risk it poses to current and future missions. Perseverance teams document any debris they find and check to see if any of it could contaminate the samples the rover collects. NASA engineers also looked into whether Perseverance could become entangled in debris from the landing, but concluded the risk was low.
The real reason debris on Mars is important is its place in history. The spacecraft and its parts are the first milestones in human planetary exploration.
This article is republished from The Conversation, an independent, nonprofit news site dedicated to sharing ideas from academic experts. It was written by: Cagri Kilic, West Virginia University. The Conversation offers a variety of fascinating free newsletters.
Cagri Kilic does not work for, consult, own stock or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond his academic appointment.
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