What Happens When You Throw a Paper Plane From Space? These Physicists Found Out

A simulated A4 paper plane takes a death dive from the ISS for science.

What would happen if you threw a paper airplane from the International Space Station? It’s just the sort of idea that might emerge from a curious child — or, as it turns out, a physicist with a flair for wonder. Maximilien Berthet and Kojiro Suzuki, researchers at the University of Tokyo, decided to find out.

Turns out, this curious experiment might actually be useful.

A Descent Like No Other

The experiment has not actually happened in orbit. The new study is a simulation-and-wind-tunnel test of what would happen if an origami paper plane were released from the International Space Station. That distinction matters: this is not a mission report, but an attempt to answer a strange and surprisingly serious physics question.

From the moment the simulated origami plane leaves the ISS (some 400 kilometers above Earth), it begins its doomed descent.

It’s not a spacecraft in any normal sense. It has no heat shield, no engine, no guidance system, and no radio. It weighs just four grams. Its surface is cellulose and kaolinite, not titanium or carbon fiber. And yet, despite all this, it flies for a while. Well, “flies”.

Thanks to its airplane-shaped folding, the paper plane is statically stable in the vacuum-like upper reaches of space. It points nose-first into the airstream, guided by the subtle aerodynamic forces acting on its paper form. This initial phase of descent, researchers found, is surprisingly calm. The plane passively maintains orientation for several days as it spirals downward, shedding altitude rapidly. “Atmospheric entry from a 400 km circular orbit occurs within a few days,” the authors write.

But then after around four days and at around 120 kilometers — just above the region where satellites begin to burn — gentle descent gives way to chaos.

Controlled Flight Gives Way to Tumbling Fire

In fairness, the test model wasn’t simply a sheet of office paper. It included an aluminum tail, a caveat worth keeping in mind before treating this as a pure “paper spacecraft.” This helped it, but only a bit.

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At about 120 kilometers above the soil, it starts to go through a thin sheet of air. As this air becomes thicker, drag and friction increase, and the plane begins to tumble. The simulations, based on equations tracking orbital mechanics, rotation, and aerodynamic drag, show the once-stable dart now spins uncontrollably.

This can only mean one thing — heat. The paper would begin to burn.

To verify their models, the researchers turned to hardware. They folded a scaled-down version of the origami plane and placed it into the Kashiwa Hypersonic and High Enthalpy Wind Tunnel in Tokyo. Then they blasted it with Mach 7 winds — over 1,000 meters per second — for seven seconds straight.

The plane’s paper nose began to bend backward under the force, forming a 3 mm ridge. The tip darkened and wing edges charred. Despite the onslaught, the plane held together — but barely.

“Combustion or pyrolysis is expected during atmospheric entry,” the authors concluded. It was, for all intents and purposes, a one-way trip.

Why Launch a Paper Plane From Space?

The idea may sound whimsical, but this tiny experiment carries weightier implications.

First, there’s sustainability. ESA’s latest public space-debris figures list about 17,610 satellites still in space, about 15,800 still functioning, and roughly 45,780 tracked space objects as of April 2026. The agency’s models also estimate more than 1.2 million objects between 1 and 10 centimeters across — too small to track reliably, but large enough to damage spacecraft.

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Paper, largely plant-based, could offer a cleaner way to dispose of lightweight objects or components through passive atmospheric reentry. Japan, for instance, launched a working wooden satellite in space that operated for 116 days. It’s launching a second, improved version soon. In fact, in 2008, Japanese researchers and origami experts explored a similar idea: releasing heat-resistant paper planes from the ISS and letting them glide back toward Earth. However, that plan never became a practical orbital experiment.

More practically, a paper plane’s rapid descent makes it a sensitive probe for studying the upper atmosphere if it were equipped with tiny sensors. Because of its low mass and large surface area, its trajectory is highly responsive to small changes in air density—information that’s still difficult to collect at altitudes between 200 and 300 kilometers.

“The paper space plane’s strong sensitivity to aerodynamic drag . . . suggests it could be used as a passive probe for atmospheric density measurement,” the authors write.

In the end, the origami space plane does exactly what you’d expect of something made from office supplies hurled into Earth’s atmosphere: it burns up.

But along the way, it teaches us something new. The lesson is not that future spacecraft will be made of paper. It is that the materials we send into orbit matter — not only while they are above us, but also when they come back down.

The study was published in the journal Acta Astronautica.

The article was originally published in July 11, 2025, and has been since updated to include additional information.