Littering on Earth typically gets you a fine if the police find out, but what about on Mars? US spacecraft have recently spotted several pieces of human-made space junk on the planet, shed during missions to the surface.
“It’s a surprise finding this here,” the Twitter account for NASA’s Perseverance rover, which is written in the first-person, tweeted on Wednesday about a piece of thermal blanket used during its descent to the planet on February 18, 2021. “My descent stage crashed about 2 km away. Did this piece land here after that, or was it blown here by the wind?”
Mars has a thin atmosphere that is too sparse to support human respiration, but which can still blow dust around and spin up dust devils that dance across its surface. Perseverance brought with it a small helicopter, Ingenuity, that has demonstrated the ability to sustain flight on the Red Planet using the same methods as on Earth.
From its airborne perch, Ingenuity has also spotted human space debris. In late April, NASA’s Jet Propulsion Laboratory, which manages the Mars mission, posted photos snapped by Ingenuity of the lander’s “parachute that helped the agency’s Perseverance rover land on Mars and the cone-shaped backshell that protected the rover in deep space and during its fiery descent toward the Martian surface.”
The photos, it noted, were taken during a flight to study the wreckage and help NASA design safer future landers. While the backshell fractured and created a debris field when it impacted the Martian surface at 78 miles per hour, almost everything else appears intact, including the parachute used to slow the lander’s descent.
There have been 15 missions to the Martian surface by the US, Soviet Union, European Space Agency, and China since 1971, several of which impacted the surface at extreme speed thanks to system failures, and most of which have become inert junk as their batteries wore out. A similar phenomenon exists on the moon and on Venus, where humans have also sent numerous spacecraft missions.
However, for now, the junk doesn’t seem to pose the same problems as space junk in Earth orbit does, which can strike astronauts, satellites, and space stations also in orbit. While spacecraft can be designed to withstand impacts by space junk or micrometeorites, as NASA’s Webb space telescope showed when it was struck for the first time earlier this month, most aren’t, and an impact could cause serious damage to equipment or be deadly to human beings.