Rocket Mailman?

Friday's One Cup of Java Challenge: In their never-ending quest for more efficient mail delivery, on this date in 1959 the US Postal Service tested a new method for delivering mail. Despite making the delivery on that date in about 23 minutes, the post office scrapped plans for further implementation of the delivery system - possibly because of customer fears during the Cold War. Your question this morning - what type of delivery system did the US Postal Service successfully test on this date in 1959?

One Cup answer: They used a rocket. Dubbed "missile mail," a Regulus cruise missile was fired. Its nuclear warhead had been replaced with two bins of mail!