Rocket Mail

by Tom Fort, the senior historian at MOSTHistory

Space-X rocket motors thunder near Boca Chica, sending sleek missiles and great exhaust clouds into the air above the winding Rio Grande. 

Some 87 years ago, their rocket ancestors also took off near the Great River. But they were much smaller, barely six feet long, and their voice was more of a loud “whoosh.”  Their payloads were not satellites headed for orbit but packets of mail headed across the Rio Grande.  It was July 2, 1936, and the First International Rocket Mail was underway!

The rocket mail experiment was the brainchild of Keith Rumbel, a high school science student in Mission/Sharyland.  An avid follower of rocketry news in various media — including the work of Dr. Robert Goddard, called the father of American rocket science — Keith read of rocket-mail flights in Europe, but none that crossed international boundaries. With experience building his own rockets, Keith Rumbel saw the nearby Rio Grande border as the perfect place to attempt international mail flights. He designed the rockets – patterned much like “Roman Candle” fireworks – and the stamp covers they would carry. With the help of his father, O. K. Rumbel, and others in the American Legion Post No. 37 in McAllen, the arrangements were made with U.S. and Mexican officials, and the day was set.

Ten home-built rockets flew across the Rio Grande that summer afternoon, five from Texas to Mexico and five from Mexico to Texas. The “launching pads” were wooden ramps set up near Hidalgo and Reynosa, each draped in their respective national colors. 

On hand were representatives from the U.S. and Mexican governments, city officials from McAllen and Reynosa, and news reporters.  The first launches, from the United States to Mexico, saw one “bird” blow up over the river, scattering stamp covers into the water. The others made it across to Reynosa: one set a nearby cornfield on fire, while another made a beeline for the “U.S. Bar,” narrowly missing an open window and hitting the outside wall. Bar patrons reportedly exited in a hurry, afraid that the roof was collapsing!

The return flights from Mexico to Texas were less eventful. No buildings were hit, but two rockets lost their stamp-laden nose cones, dumping the covers into the river (none were recovered).  In all, some 2,000 stamp covers crossed the southern border successfully that July day.

Although mail carried by airplanes would end postal rocket experiments, the flights across the Rio Grande in 1936 were significant. Rumbel and his fellow students who helped carry out the flights probed a new scientific frontier. In later years, Rumbel became an actual rocket scientist, working on developing the Talos and Polaris guided missile systems. Today, examples of the postal covers designed and printed by Keith Rumbel and carried that day across the Rio Grande reside in the MOSTHistory archives.