This sounds crazy, but it’s been done before – in 1959. That year, a Navy sub called the U.S.S Barbero launched 3,000 letters via a rocket. It was considered a success.

The Postmaster General at the time, was so impressed that he predicted that repurposing ‘instruments of war into instruments of mail’ would become commonplace. Mail would take hours to reach the far corners of the world, rather than days.

Of course, he didn’t know about email at the time.