Space junk should be burning up upon re-entry, but it’s not.

What Goes Up…

Space may be boundless, but the increasingly cluttered orbital real estate where we like to cram all our satellites is not. And so as we enter a golden age of commercial spaceflight, those of us on terra firma may not be able to write off death by falling space junk as an astronomically remote implausibility forever.

As Ars Technica reports, hunks of space hardware keep falling to Earth despite engineers insisting that they should’ve safely burned-up in the atmosphere — like in the case of a piece of the International Space Station crashing through the roof of a Florida home, or a suspected chunk of a SpaceX Dragon spacecraft touching down on a Canadian farm.

Those examples are just from this year, and in the former’s case, came uncomfortably close to being deadly — and some experts warn that we don’t have a good enough grasp on why this keeps happening.

“The biggest immediate need now is just to do some more work to really understand this whole process and to be in a position to be ready to accommodate new materials, new operational approaches as they happen more quickly,” Marlon Sorge, executive director of  The Aerospace Corporation’s Center for Orbital and Reentry Debris Studies, told Ars Technica. “Clearly, that’s the direction that spaceflight is going.”

Chaotic Conditions

Government bodies like NASA and the European Space Agency agree that space junk is a pressing problem. It’s their garbage up there, after all, along with ever-increasing proportions of commercial junk from the likes of SpaceX, whose giant and ever-growing satellite constellations have raised concern at the Federal Aviation Administration.

Most of the attention around the issue has been focused on how to build the machines — be it a specialized spacecraft or a giant laser — to safely deorbit the junk, which will soon include the ISS.

Designing these machines will be engineering conundrums on their own, but the complicated mechanics of falling through the atmosphere should not be underestimated. Modern spacecraft are built with lightweight composites that shouldn’t have a chance of surviving the scorching hot temperatures of a re-entry — and yet, somehow, they keep doing exactly that.

“It’s not just the materials that go into the composite,” Greg Henning, manager of the debris and disposal section within Aerospace’s space situational awareness department, told Ars. A host of factors could be at play, including how those materials are constructed, or even much more difficult to predict factors like the orientation of the falling junk.

“Is it tumbling? Is it reentering in a stable configuration? There are so many things that go into what actually happens during a reentry,” Henning continued. “It just makes it that much more complex to figure out if something is going to survive or not.”

There are no easy answers right now, but these long-term problems are something we’ll have to not just mull over, but eventually take action on as we keep launching more stuff.

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