What gas do airships fly on: helium, hydrogen or air? | New Generation Airships

Airships are lighter-than-air aircraft that once dominated the skies and are now experiencing a technological renaissance. Their ability to float in the air depends on the gas that fills their envelopes. But which gas exactly is used today—helium or hydrogen? And why is the choice of gas so important for safety, efficiency, and the future of airship construction? In this article, we'll examine in detail the history, physics, and modern trends to answer the main question: what gas do airships fly on?

At the beginning of the aeronautics era, in the 19th and early 20th centuries, the main gas used to fill airships was hydrogen. Why? Because it was the lightest known gas—its molecular mass is only 2 g/mol, which provided maximum lift. Additionally, hydrogen could be produced relatively cheaply and in large quantities—for example, through the reaction of zinc with sulfuric acid or electrolysis of water.

The first controlled airships, the devices of French engineer Henri Giffard (1852) and German Count Ferdinand von Zeppelin (early 1900s), used hydrogen specifically. It allowed them to lift significant loads and develop speeds unattainable for balloons. Hydrogen filled the airships of all leading powers—Germany, France, Great Britain, the USA. This was the golden age of airships, but it proved tragically short.

The hydrogen airship was a true marvel of technology for its time—enormous metal frames covered with fabric, filled with thousands of cubic meters of gas, could cross the Atlantic and carry dozens of passengers. But behind the lifting power lurked danger: hydrogen ignites easily.

The advantages of hydrogen as a filler are obvious: it's almost 14 times lighter than air, provides excellent lift, is cheap to produce and available. A hydrogen airship could carry more cargo, fly longer and required less fuel to maintain altitude. However, its main disadvantage—high flammability—negated all the advantages. Today we have combustion control technologies, but back then they hadn't been heard of yet.

History knows many disasters related to hydrogen combustion. The most famous is the Hindenburg airship disaster on May 6, 1937, in Lakehurst, USA. The huge German Zeppelin, arriving from Frankfurt, caught fire during landing and burned in minutes. Of 97 people on board, 36 died. The cause—a spark (possibly static electricity) ignited the hydrogen. Videos and photographs of the disaster spread around the world and forever undermined trust in hydrogen airships.

Before the Hindenburg, there were other tragedies: explosions of the airships R101 in Great Britain (1930), USS Shenandoah in the USA (1925), LZ 4 in Germany (1908). Each of them forced engineers to search for alternatives. The combustion and explosion of hydrogen became the main reason for abandoning its use in civil aviation. The military continued to use hydrogen airships until the end of World War II, but after that the era of hydrogen in aeronautics ended.

Helium is the second lightest element after hydrogen, but unlike it, is absolutely inert. It doesn't burn, doesn't explode, doesn't enter into chemical reactions. A helium airship is a guarantee of safety. That's precisely why after the Hindenburg disaster all new civilian airships began to be filled with helium.

The first helium airship—the American USS Shenandoah—was built back in 1923, but due to helium shortage and its high cost was rarely used. Helium was mainly extracted in the USA, where the largest natural gas deposits with high helium content were located. In 1927, the US Congress even banned helium export, fearing it could be used for military airships by potential adversaries.

Helium yields about 8% less lift than hydrogen, but this difference is compensated by safety. Modern airships—advertising, tourist, scientific—use exclusively helium. For example, the famous Goodyear airships that can be seen over stadiums and cities are filled with helium. They carry less cargo than their hydrogen predecessors, but are absolutely safe even in accidents.

Additionally, helium is non-toxic, has no smell or color, doesn't cause corrosion of envelope materials. Its only minus is price and limited resources. Helium is a non-renewable resource, its extraction is complex, and world reserves are depleting. This stimulates scientists to search for alternatives, but for now helium remains the gold standard for airships.

Today the gas used in airships is almost exclusively helium. Helium production and storage technologies have significantly improved, recovery and reuse systems have appeared, which reduces operating costs. What inert gas is used to fill airships? Only helium—there are simply no other suitable inert gases for lightness and safety. Neon, argon, krypton—all are heavier than air and not suitable for creating lift.

What do modern airships fill with? High-purity helium (99.995% and higher) to avoid impurities that could affect lift or safety. Multi-layered envelopes made from modern composite materials are also used, which minimize helium leakage—unlike the fabric envelopes of the last century.

In recent years, hybrid airships have appeared—combining aerostatic lift (from helium) and aerodynamic lift (from body shape and engines). They're capable of transporting heavy cargo to hard-to-reach areas—for example, Lockheed Martin developed the hybrid airship LMH-1, designed for cargo transportation in the Arctic and mountainous regions.

Research is also being conducted on creating airships with systems for capturing and reusing helium, making them more environmentally friendly and economical. In the future, airships powered by a mixture of helium with other gases or even warm air may appear—but for now these are experimental projects.

Air for filling an airship isn't suitable—because it's not lighter than itself. For an aircraft to become lighter than air, its internal volume must be filled with a substance with lower density than the surrounding atmosphere. Air consists mainly of nitrogen (78%) and oxygen (21%), its density under normal conditions is about 1.225 kg/m³. None of the air components will provide lift unless heated.

However, there's an exception—warm air airships, similar to hot air balloons. The principle is simple: heated air expands, its density decreases, and the aircraft becomes lighter than the surrounding cold air. Such airships exist—for example, Thermal Airship projects or the Santos-Dumont project in Brazil. They're safe, cheap to operate, don't require expensive gases. But they have serious disadvantages:

• Low lift compared to helium or hydrogen;

• Need for constant air heating, which requires high fuel consumption;

• Difficulty controlling at high altitudes where ambient air temperature drops;

• Limited payload capacity and flight range.

Thus, air for filling an airship in its pure form is not used. Only in a heated state—and then, as a niche for specific tasks: tourism, advertising, observation at low altitudes.

So what gas do airships fly on today? The answer is unequivocal—helium. Hydrogen remained in the past due to its explosiveness, despite superior lifting characteristics. Helium—safe, inert, reliable—has become the main gas for all modern airships. Air cannot serve as a filler without heating, and alternative technologies haven't yet gone beyond experiments.

The future of airships lies with hybrid systems, new materials and, possibly, synthetic helium or other innovations. But for now, if you see an airship in the sky—you can be sure: there's helium inside. Safety, reliability and peace of mind—that's what matters most in aeronautics today.

You can participate in creating such safe, economical and environmentally friendly airships. We explain how to do this here.