Astronauts still have to file their taxes on April 15 every year -- even if they're floating in outer space.

HONG KONG (CNNMoney)

Yes, that's right. Astronauts are on the hook to file taxes by April 15, even if they're orbiting hundreds of miles above Earth on a long-term mission.

The IRS -- the much-feared enforcer of the U.S. tax code -- makes no exceptions. Experts say astronauts don't get special treatment, no matter how far away they are from the planet.

NASA astronaut Leroy Chiao -- commander of the tenth expedition to the International Space Station -- was in orbit when tax day rolled around in 2005. Chiao had no choice but to manage his taxes from space.

But how exactly did that happen?

"Get someone to help you out on the ground," Chiao said. The mission commander's sister is an accountant, and she was able to file papers on his behalf to extend his tax return deadline.

"He certainly had a good, valid reason [for the extension]," said his sister, Judy Chiao Smith.

Related: This job has the world's worst tax return

After eight months living on the International Space Station, Chiao returned to earth on April 24, 2005 -- just nine days after tax day -- and got busy working on his tax return.

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Nobody escapes U.S. taxes - even astronauts