NASA didn't send a female astronaut into space until Sally Ride in 1983. So imagine mission control's surprise when, some 10 years earlier, they heard a woman's voice in a transmission from the Skylab space station.
In 1973, Owen K. Garriott spent just less than 60 full days orbiting Earth on this NASA craft. Meanwhile, the flight's Earth-bound support crew included communications specialist Robert "Bob" Crippen (an astronaut himself) among its ranks. One day, the space station sent Crippen a weird message. "Hello Houston, this is Skylab," someone said. "Are you reading me down there?" The voice sounded distinctly female and couldn't belong to any of the three men aboard the vessel. When Crippen asked who was on the line, the caller identified herself as Helen Garriott — Owen's wife.
Naturally, Crippen asked what she was doing up there. "Well, we just came up to bring the boys a fresh meal, or a hot cooked meal. They haven't had one for quite a while. We thought they might enjoy that," Helen replied. She then nonchalantly said she'd flown out to the Skylab and made some comments about how California looked from space. By now, a bewildered crowd had gathered around Crippen's speakers. Finally, Helen signed off, saying "Well, I see the boys are floating in my direction. I've got to get off the line. I'm not supposed to be talking to you. See you later, Bob."
It didn't take Houston long to figure out that this entire exchange must've been a practical joke — one Garriott was undoubtedly in on. But how did he pull it off? With careful planning, that's how. Beforehand, Garriott had written down some lines for his wife to read and recorded her doing so. He also made sure to punctuate her comments with pauses in the audio. This gave Crippen — who'd agreed to help out — enough time to offer scripted replies to Helen's statements.
Magicians like to guard their secrets. According to Garriott, NASA didn't figure out how he'd orchestrated this particular gag until he finally explained his methods to them in 1999.