The tiny astronaut, nicknamed Mojo Man, was sent 20 miles into the stratosphere attached to a weather balloon.
Shaun Whitehead launched the man as part of an experiment with permission from the Civil Aviation Authority. Mojo Man completed his mission and was pictured at 110,000ft above Earth.
However, he became detached from the equipment when it floated back down to the ground and is thought to have landed somewhere near Leicester.
Shaun, from Grimston, said: "I've always wanted to try taking some photos on the edge of space. I needed a test item for the launch and Mojo Spaceman was a bit of fun.
"The project worked perfectly and we captured 2.5 hours of high definition video of the flight from launch to landing. The rest of the equipment eventually landed but sadly there was no sign of the astronaut.
"We've looked at the video and think he was knocked off his perch when the balloon burst and fell somewhere around Leicester.
"The plastic he is printed from, ABS, is also very tough so I have high hopes for his survival and if someone finds him I'd love them to get in touch."
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