On Mars, there is a unique type of “tumbleweed” that rolls over the Martian plains.
These tumbleweeds are not plants – they are pieces of debris from entry, descent and landing (EDL) equipment from NASA’s Perseverance rover. Percy has come across many of these remains, photographed them for engineers to study.
Under his lands on February 18, 2021, a series of hardware elements reduced the spacecraft’s speed from 12,500 mph (20,000 km/h) when it first entered the Martian atmosphere to essentially zero miles per hour when it was carefully placed on the surface of a sky crane. And it all happened in just seven minutes.
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Once their jobs were complete, EDL hardware such as the parachute, backshell, heat shield, and sky crane were ejected from the Perseverance rover, crashing into Mars some distance away from the rover so as not to damage it.
Over the past year and a half, the Perseverance team has discovered and cataloged about half a dozen pieces of suspected EDL debris. The first piece was discovered on April 16, 2022, when an unusually bright object was spotted in one of Perseverance’s panoramic Mastcam-Z images. “The material was given a descriptive name: ‘luminous material.’ No one knew what it was at the time, but perhaps the rover would take a closer look as it climbed the delta in the coming weeks,” NASA wrote in a blog posts (opens in a new tab).
Several months later, Perseverance came to that place in the delta, called Hogwallow Flats. On June 12, 2022, it photographed the mysterious object, suspected to be a piece of multi-layer insulation (MLI) from the sky crane, made of either perforated aluminized kapton (PAK) or Mylar, fluttering in the wind like a flag. . In the same region, the rover also captured a snapshot of a fast-moving ball of “string-like material”. It could be Dacron, a mesh used in thermal blankets, according to the operations team.
Interestingly, Hogwallow Flats is more than 1.25 miles (two kilometers) away from the crash zones of Perseverance’s EDL hardware. “The Hogwallow Flats appear to be a natural collection point for windblown EDL debris,” notes NASA.
Perseverance’s helicopter entourage Ingenuity have come close to some of the EDL waste. On 19 April 2022, Ingenuity flew over the crash site of Perseverance’s rear shell and parachute, take high-resolution images of debris.
Such fields of intentionally discarded debris are not uncommon on Mars, as landings on the Red Planet are usually somewhat violent events. Both Possibility and Curiosity rovers have also photographed what is suspected to be their own EDL debris.
For now, landing spacecraft on Mars is the first priority, but as we continue to plant rovers on the planet, scientists must consider the effects of such space junk. “Engineers designing EDL hardware for future missions must consider the impact (literally) of their designs on both Mars and the mission requirements,” NASA said.