Throughout the next months, the Smithsonian Institution Archives will feature posts related to the Smithsonian and the Civil War in honor of the 150th anniversary of the American Civil War.

One hundred and fifty years ago, on June 18, 1861, a balloon ascended on the National Mall at the spot where the National Air and Space Museum is located today and, later, from sites near the Smithsonian Castle and White House. Although watching balloon ascents had become a popular pastime since the first one was sent aloft by Joseph and Jacques-Ètienne Montgolfier in 1783, this event was specifically designed to demonstrate the utility of using balloons for military intelligence.

The balloon was piloted by Thaddeus S. C. Lowe, founder of the first aerial reconnaissance unit for the U.S. military. Even before the Civil War, Lowe had turned to the Smithsonian for advice about ballooning. In December of 1860, a group of sixteen citizens from Philadelphia wrote to Smithsonian Secretary Joseph Henry asking that the Smithsonian support Lowe’s experiments in ballooning, especially his planned attempt to cross the Atlantic. Henry was dubious that such ambitious aerial navigation was possible, and the Smithsonian Board of Regents declined to provide financial aid for the experiment.

Lowe, however, knowing the importance of air currents for steering balloons was also interested in meteorology. And familiar with the Smithsonian’s Meteorological Project, forerunner of the U.S. Weather Service, he  wrote directly to Secretary Henry on February 25, 1861, asking for information about air currents that might aid balloon navigation. In his reply of March 11th, Henry wrote, “I have never had faith in any of the plans proposed for navigating the atmosphere, by artificial propulsion, or of steering a balloon in a direction different from that of the the current in which the vehicle is floating.”  Despite his skepticism, Henry did provide what information he had available.

But by May 28th, and with the nation at war, Henry was more encouraging to Lowe, asking him to pursue the use of balloons for aerial reconnaissance around the Nation’s capital. Henry saw real potential for military aerial reconnaissance, since a balloon’s movement could be confined to a small area and the pilot could use the telegraph, one of Henry’s great interests, to send back results to those watching and waiting below. Over the next month, Henry introduced Lowe to President Abraham Lincoln, Secretary of War Simon Cameron, and other government officials, and provided him with additional advice. For reconnaissance purposes, the balloon would be tethered to a military wagon and towed in a twenty mile radius as the pilot used binoculars to survey the region. Henry suggested that “aeronauts” observe the topography, to aid in Union troop movement, and assess Confederate troop movement, supplies, and strength. The observations from the air would then be telegraphed down to a station below, providing real time aerial reconnaissance. Secretary Henry had been a key player in the discovery of electromagnetism and the invention of the telegraph, so he provided advice on how to establish this telegraphic network.

After Henry observed the June 18th test flight—which demonstrated that successful telegraph communications were possible on far longer lines than previously believed—he became a staunch advocate of Lowe’s work which soon led to the creation of a Balloon Corps within the Union Army. The aeronauts successfully located Confederate forces, reported on force strength, and directed artillery fire at Confederate positions. While some generals at the time and historians today question the value of the Balloon Corps, its observations forced the Confederates to spend resources and time camouflaging their encampments and allayed Washingtonian’s fears of imminent invasion on more than one occasion.

In June, the National Air and Space Museum recreated the historic balloon test. Learn more about this story from NASM’s curator Tom Crouch, who has written on the history of ballooning, and see other objects relating to Thaddeus Lowe in the Smithsonian’s collections.