KASHIWA, Japan (AP) -- Japanese scientists and origami masters hope to launch a paper airplane from space and learn from its trip back to Earth.
It's no joke. A prototype passed a durability test in a wind tunnel last month, Japan's space agency adopted it Wednesday for feasibility studies, and a well-known astronaut is interested in participating.
A successful flight from space by an origami plane could have far-reaching implications for the design of re-entry vehicles or space probes for upper atmospheric exploration, said project leader Shinji Suzuki, a professor at Tokyo University's Department of Aeronautics and Astronautics.
Suzuki said he was skeptical a decade ago when he first discussed with experts the idea of sending into space a craft made in the tradition of Japan's ancient art of paper folding.
"It sounded like a simply impossible, crazy idea," Suzuki said. "I gave it some more thought, and came to think it may not be ridiculous after all, and could very well survive if it comes down extremely slowly."
In a test outside Tokyo in early February, a prototype about 2.8 inches long and 2 inches wide survived Mach 7 speeds and broiling temperatures up to 446 degrees Fahrenheit in a hypersonic wind tunnel -- conditions meant to approximate what the plane would face entering Earth's atmosphere.
Having survived the 12-second test with no major damage or burns, the tiny plane theoretically could get back to Earth because re-entry from outer space involves passing through several layers that last only a few seconds each, said Osamu Imamura, a scientist who works with Suzuki.
The Japan Aerospace Exploration Agency, or JAXA, accepted it Wednesday for three years of feasibility studies and promised up to $300,000 in funding per year.
At this point, the proposal faces just one challenge, but it's a potentially crippling one: There is no way to track the paper craft or predict when or where they may land.
Critics say that makes the test pointless. Yasuyuki Miyazaki, an aerospace engineer at Nihon University who is not involved in the project, said the paper shuttles might not come back at all, depending on the angle at which they enter the atmosphere.
Suzuki said many things about science "have to be learned simply by trying them out."
Takuo Toda, the head of the Japan Origami Airplane Association, had nursed the idea of flying a shuttle-shaped paper plane since NASA in 1977 launched its first space shuttle Enterprise, a craft without an engine or heat shield that was used to perform test flights in the atmosphere.
He spent 18 months figuring out how to fold a perfect origami spacecraft from a plain sheet of paper -- without cutting, stitching or taping it -- and tested hundreds of designs in the process.
"Then I thought, perhaps I could someday have it fly back to earth from space," Toda said. "Nobody took it seriously, saying it would burn instantly."
Toda and Suzuki first met about 10 years ago, when Suzuki and other scientists attended Toda's launching of a 6.6-foot-long giant paper craft from the top of a mountain. The successful flight impressed Suzuki, and Toda revealed his long-cherished dream.
The effort has been a labor of love. It's had no outside funding so far, relying on paper donated by the origami association and Suzuki's access to Tokyo University equipment.
The project has inspired curiosity in the scientific community in Japan.
"You may think it's impossible, but we scientists are all extremely interested. I think it's a great experiment," said Miyazaki, the Nihon University engineer.
"No matter how it turns out, a paper craft flight from space would tell us many things," Miyazaki said. "The fact that a paper shuttle has endured the harsh environment in the lab tests also provides valuable data for future aerospace technology."
Suzuki and Toda use origami paper made of sugar cane fibers that are resistant to heat, wind and water. They spray a special coating onto the paper and then fold it into shuttles about 8 inches long and 4 inches wide that weigh about 1.05 ounces. How many shuttles will be released has not been decided.
The pair theorize that with the coating, rounded edges, a rounded nose cone and almost no weight, their craft will face very little of the heat-generating friction that causes most damage to vehicles re-entering Earth's atmosphere.
Astronaut Koichi Wakata, who has expressed personal interest in the project, would throw several origami shuttles into the wake of the international space station, which travels at Mach 20 some 250 miles above Earth -- if the JAXA feasibility studies pan out, Suzuki said.
Findings from the paper shuttles' flight could be used in developing new lightweight space probes that would study the upper atmosphere, Miyazaki said. The results could also help in designing a full-scale shuttle that re-enters the atmosphere slowly to reduce fiction and heat, said Suzuki.
Suzuki and Toda plan to write a message of peace on the planes in several languages, along with a request for anyone spotting them to notify the team.
"Just imagine, children around the world would be anxiously waiting for the return of our origami shuttle, perhaps looking up into the sky from time to time," Suzuki said. "That would be great fun."