Balloon Corps , civilian aeronautical unit (1861–63) created during the American Civil War to provide aerial surveillance of Confederate troops for the Union army. Balloons supported Union campaigns from ground stations and naval vessels in the Peninsular Campaign, the capture of Island Number Ten, the Savannah Campaign, and the Battle of Chancellorsville.

Lowe, Thaddeus S.C.; Balloon Corps Thaddeus S.C. Lowe of the Union army's Balloon Corps observing battle from the balloon Intrepid during the Peninsular Campaign of the American Civil War, May 1862. Library of Congress, Washington, D.C. (reproduction no. LC-DIG-cwpb-01560)

American Civil War: Balloon Corps Union army Balloon Corps ground crew replenishing the balloon Intrepid at Fair Oaks, Virginia, May 1862, during the American Civl War. Library of Congress, Washington, D.C. (reproduction no. LC-DIG-cwpb-01563)

Top Questions What was the Balloon Corps? The Balloon Corps was a civilian aeronautical unit created during the American Civil War to provide aerial surveillance of Confederate troops for the Union army. It was in existence from 1861 to 1863. How did the Balloon Corps influence the outcome of the American Civil War? The Balloon Corps’s influence on the outcome of the Civil War was limited. Conservative generals were skeptical of balloons’ usefulness during war, and the corps’s intelligence reports were often imprecise. The Balloon Corps most notably warned Union forces of a Confederate attack at the Battle of Seven Pines in 1862 but had few significant achievements. It was dissolved before the end of the war. Why was the Balloon Corps important? The Balloon Corps was important to the Union army because its balloons were able to observe Confederate positions and support Union artillery fire while remaining out of range of enemy fire. It played an important role in mapmaking and was a constant source of harassment and annoyance to the Confederates.

Most balloonists before 1861 made their living as carnival performers and itinerant “professors” of chemistry. Both Thaddeus S.C. Lowe of New Hampshire and John La Mountain of New York combined entertainment with long-distance test flights. Both men also employed balloons as aerial observation platforms for the Union army.

Aeronauts used their balloons in free flights and in tethered ascents. Free flights proved difficult because wind direction varied according to altitude. Aeronauts guided their balloons upward by emptying 100-pound (45-kg) sandbags carried as ballast, and they descended by venting hydrogen from the envelope (the actual balloon portion of the lighter-than-air craft) and then riding the easterly or westerly air currents. That method of navigation proved hazardous on several occasions when balloonists drifted into Confederate-occupied territory in Virginia. On April 19–20, 1861, Lowe undertook an experimental night flight from Cincinnati, Ohio, that had no military objective and was intended to land in the vicinity of Chesapeake Bay. Instead, he landed in South Carolina only a week after the Confederate bombardment of Fort Sumter, causing him to make his way back to Cincinnati by wagon, train, and steamboat.

The Balloon Corps generally conducted only tethered ascents rising to 500 feet (150 metres), which afforded a 15-mile (24-km) range of vision, depending on the terrain. Tethered ascents kept the balloon generally stationary but required ground crews of up to 30 soldiers to quickly raise and lower the balloon, which was threatened by Confederate artillery and sharpshooter fire on every launch and descent. Tethered ascents improved the aeronauts’ observations but also immediately gave away the position of the ground station—usually collocated with the division or corps headquarters to expedite the transmission of observations. Thus, Confederate bombardment often fell on the headquarters as well.

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Lowe began operations in Washington, D.C., where he demonstrated the balloon’s military applicability for U.S. Pres. Abraham Lincoln, whereas La Mountain worked at Fort Monroe, Virginia, observing Confederate activity in the summer of 1861. La Mountain’s tethered balloon ascent from the steam-powered gunboat Fanny on August 3, 1861, is considered by many scholars to be the first flight from a precursor of the aircraft carrier. His final vessel-launched ascent was from the Adriatic on August 10. Lowe followed by ascending from the first boat modified for balloon operations, the George Washington Parke Custis, on November 11, 1861. The Custis supported balloon operations along the Potomac River and accompanied the army during the Peninsular Campaign.

Lowe and his assistant aeronauts flew the balloons Intrepid, Constitution, and Washington during the Peninsular Campaign with the Army of the Potomac with mixed results. Lowe’s ascents at Yorktown could not shake Union Gen. George McClellan’s mistaken conviction that Confederate forces there outnumbered his own or inspire him to attack the weakly defended Yorktown lines. The Balloon Corps’s most famous and controversial contribution was Lowe’s warning of an impending Confederate attack against the Union III Corps at the Battle of Seven Pines on May 31, 1862. Lowe contracted malaria shortly after that battle.

The Balloon Corps made no significant intelligence contributions to the Seven Days’ Battles (June 25–July 1) and deployed to Harrison’s Landing, on the James River, with the remainder of the Army of the Potomac. The aeronauts operated from naval vessels along the James River in July 1862 but did not take part in the Battle of Antietam in September.

Lowe’s assistant aeronaut John Starkweather observed Confederate positions around Savannah, Georgia, after the capture of Fort Pulaski on April 15, 1862. McClellan had assigned aeronaut John Steiner and the balloon Eagle to Gen. John Pope’s Army of the Mississippi in February 1862, but Pope ignored them. In March and April 1862, however, Flag Officer Andrew Foote employed Steiner and the Eagle as an aloft artillery-spotting platform against Confederate positions on the Mississippi River’s Island Number Ten (about 55 miles [88 km] below Cairo, Illinois). The officer with whom Steiner ascended recommended firing corrections to the mortar boats in Foote’s flotilla. Aided by the corrections, the naval mortars wrecked many Confederate guns, allowing Pope’s forces to capture New Madrid, Missouri, and the island on April 7, 1862, but Foote made no mention of Steiner’s contribution in his official report after the battle.

Balloons operated in Falmouth, Virginia, supporting Gen. Ambrose E. Burnside’s operations before the Battle of Fredericksburg in December 1862, but, attempting to lull into complacency the Confederates positioned across the river, Burnside ordered the balloons grounded for several days right before the battle, thus possibly depriving himself of observations of Confederate troop movements that might have proved invaluable in the conflict. Union balloons operated for the last time during the Battle of Chancellorsville (May 1–5, 1863); however, fog and winds combined to minimize the balloons’ flights and usefulness as observation platforms.

Both Lowe and La Mountain used portable hydrogen generators to inflate their balloons. Whereas La Mountain built his own generator, Lowe obtained the support of the Washington Navy Yard to construct large portable hydrogen generators that fit on a standard army wagon. That portable system generated hydrogen through the careful mixing of iron shavings and sulfuric acid inside a copper-lined box and pumped it into the silk envelope through a series of tubes and coolers.

American Civil War: Balloon Corps Union army Balloon Corps ground crew working on aeronaut Thaddeus S.C. Lowe's balloon near Gaines Mill, Virginia, during the American Civil War, June 1, 1862; photograph by Mathew Brady. Library of Congress, Washington, D.C. (reproduction no. LC-DIG-ppmsca-33091)

Conservative generals proved reluctant to employ the balloons. They dismissed the balloons as ridiculous carnival attractions and the aeronauts as obnoxious charlatans. Commanders remained comfortable with long-established methods of intelligence collection through scouts, spies, prisoners, and deserters. It is true that the aeronauts’ intelligence reports remained frustratingly vague throughout the war and irritated battlefield commanders. Reports drafted by officers who had traveled aloft with them tended to be more precise, but commanders rarely assigned their officers to balloon duty. Those conditions, combined with Lowe’s acrimonious relationship with his final staff supervisor, Capt. Cyrus B. Comstock, led to Lowe’s resignation from the army on May 7, 1863.

Despite aeronauts’ ability to observe Confederate positions and support Union artillery fire, absent a decisive operation upon which to hang the Balloon Corps’s reputation, indifference or hostility to the new technology of flight combined with ineffective intelligence reporting and individual personality conflicts led to the dissolution of the Balloon Corps in May 1863.