The day the Navy mailed a letter with a missile

The crew of the USS Grayback prepares a Regulus II missile for launch. (US Navy)

This day in Navy history ....

On Sept. 16, 1958, the USS Grayback became the first American submarine to successfully fire a Regulus II surface-to-surface missile from sea. It represented an important step forward in military technology; the country was developing the ability of submarines to attack land targets with cruise missiles. The Grayback, which had been operating off Southern California, went on to conduct missions while heavily armed with the missile, helping introducing a new area of national defense.

But that's not the entire story. The missile the Grayback fired that day carried a piece of U.S. mail. This will sound odd, but postal officials had a serious interest at the time at delivering mail this way. They called it "rocket mail." (Talk about going postal.) The following year, a different American sub, the Barbero, used a Regular to deliver 3,000 pieces of mail.

'Rocket' mail from the USS Barbero. (U.S. Navy)

Dictionary.com recalls the experiment this way: "In 1959 the U.S. Navy submarine USS Barbero assisted the Post Office Department, predecessor to the United States Postal Service (USPS) in its search for faster mail transportation with the only delivery of "Missile Mail". On 8 June 1959, Barbero fired a Regulus cruise missile — its nuclear warhead having earlier been replaced by two Post Office Department mail containers — at the Naval Auxiliary Air Station in Mayport, Florida. Twenty-two minutes later, the missile struck its target. The Regulus cruise missile was launched with a pair of Aerojet-General 3KS-33,000 [3 sec duration, 33,000 lbf (150 kN) thrust] solid-propellant boosters. A turbojet engine sustained the long-range cruise flight after the boosters were dropped.

"The USPS had officially established a branch post office on Barbero and delivered some 3000 pieces of mail to it before Barbero left Norfolk, Virginia. The mail consisted entirely of commemorative postal covers addressed to President of the United States Dwight Eisenhower, other government officials, the Postmasters General of all members of the Universal Postal Union, and so on. They contained letters from United States Postmaster General Arthur E. Summerfield. Their postage (four cents domestic, eight cents international) had been cancelled "USS Barbero Jun 8 9.30am 1959" before the boat put to sea. In Mayport, the Regulus was opened and the mail forwarded to the post office in Jacksonville, Florida, for sorting and routing."

It was an interesting experiment, but "rocket mail" never caught on. It proved to be impractical and prohibitively expensive.