How was the world's first hydrogen balloon built?

Inspired by hot air balloons, inventor Jacques Charles decided to build a hydrogen-powered balloon, which he considered safer.

Illustration of Jacques Charles and his first human hydrogen balloon flight with Nicolas-Louis Robert on December 1, 1783. (Photo: Amusing Planet).

On June 4, 1783, the Montgolfier brothers first publicly demonstrated a hot air balloon in southern France. The balloon is made from paper-lined sack cloth, flies to a height of nearly 2 km and remains in the air for 10 minutes. News of their success quickly spread to Paris and sparked the interest of Jacques Charles , a French inventor and scientist knowledgeable about the properties of gases.

After studying the works of researcher Robert Boyle and contemporaries such as Henry Cavendish, Joseph Black, Tiberius Cavallo, Charles believed that hydrogen was more suitable for lifting balloons than hot air. He believes that hot air balloons are quite dangerous with open flames, hydrogen is flammable, but being completely enclosed in the balloon is safer.

Jacques Charles decided to build a new airship. He hired two engineers, brothers Anne-Jean Robert and Nicolas-Louis Robert, to help build what would become the world's first hydrogen airship. To finance this expensive undertaking, naturalist and geologist Barthélemy Faujas de Saint-Fond opened a public subscription fund and sold tickets for the balloon demonstration. The Parisian elite, after witnessing the impressive flight of the Montgolfier brothers a few weeks earlier, eagerly signed up.

Charles designed an airship and asked the Robert brothers to build a light but airtight airbag. The Robert brothers devised a method of dissolving rubber in a resin solution and using this solution to coat silk sheets, making them airtight. Then they sewed the silk panels together to make the main cover.

The balloon is relatively small, about 4m in diameter and can only lift about 9kg. To inject hydrogen into the balloon, a large amount of hydrochloric acid was first poured into a container containing iron filings. The hydrogen produced is fed into the balloon through a tube connected from the tank.

The process of pumping the first hydrogen balloon. (Photo: National Air and Space Museum)

On August 27, 1783, the world's first unmanned hydrogen balloon took off from the Champ de Mars, Paris. The balloon flew up just as a thunderstorm began to come. But the bad weather did not dampen the enthusiasm of the crowd gathered below. The balloon flew straight into the sky and disappeared among the clouds in just a few minutes.

About 45 minutes after takeoff, the balloon lost some of its hydrogen, descended and landed in a village located 24km north of Paris. The villagers at that time did not know about the existence of the balloon and were frightened by its sudden appearance from the sky. They attacked the strange object with many agricultural tools and guns.

Buoyed by the success of their first flight, Charles and the Robert brothers began preparing for their next attempt - putting one or two people on a balloon. On December 1, 1783, Charles and Nicolas-Louis climbed into a balloon and flew to a height of about 500 m. They flew for 2 hours and 5 minutes, traveled 36 km, then landed safely on the Nesle plain, north of Paris at sunset.

Nicolas-Louis stepped down and Charles took off again, this time flying quickly to an altitude of about 3,000 m and seeing the Sun again. However, the sharp pain in his ears due to the low atmospheric pressure began to make him uncomfortable and he had to descend. He landed softly at Tour du Lay, about 3km away.

Despite this successful flight, Charles decided not to fly again, although he continued to design airships. One of his designs was a long, directionally controllable airship, built according to the proposal of French mathematician Jean Baptiste Meusnier. This vehicle was equipped with rudders and paddles to create propulsion, but they proved ineffective.

On July 15, 1784, the Robert brothers flew in this balloon for 45 minutes. The Robert brothers then continued flying with M. Collin-Hullin on September 19, 1784. They flew for 6 hours and 40 minutes, covering a distance of 186 km from Paris to Beuvry near Béthune, becoming the first balloonists to travel more than 100 km.