It proved to be impractical and prohibitively expensive. It was an interesting experiment, but 'rocket mail' never caught on. required a surface launch, thereby making the submarine vulnerable to attack. Rickover urged the authors to undertake a history. In Mayport, the Regulus was opened and the mail forwarded to the post office in Jacksonville, Florida, for sorting and routing.' Stumpf, Regulus: Americas First Nuclear Submarine Missile (Paducah, KY: Turner. Having read The New World, the first volume in the Atomic Energy Commissions historical series, Admiral. Their postage (four cents domestic, eight cents international) had been cancelled 'USS Barbero Jun 8 9.30am 1959' before the boat put to sea. They contained letters from United States Postmaster General Arthur E. Polaris missiles were solid-fuel SLBMs with a range of twelve. 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. 5 The Polaris missile was the crowning achievement of the first generation of nuclear submarines. '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. In the beginning, when the missiles were cruise missiles like the Regulus 1, the submarines had to surface to launch the weapon.