The balloon contains camera footage taken on the edge of the solar system, and it flew up to 100,000ft before bursting and plummeting into the sea.
It was released from Bristol last week and fitted with a GPS tracker, but has travelled further than the group collecting its data expected.
Travel fears over Yorkshire coast's tourism boomIt was last detected 14 miles off the coast of Bridlington, and its owners are offering a reward to anyone who finds it.
The cameras were strapped into a white polystyrene box that has been designed to float.
These photos will remind you of summer holidays on the Yorkshire coastIf you find the item, contact our sister paper the Bridlington Free Press on 07803 506517 and they will put you in touch with the owners.