There’s an effort underway in France to build an airship for a flight around the world without using fossil fuel. The upper surface of the airship will be covered with solar panels driving electric motors, as the illustration above shows. A fuel cell powered by hydrogen will provide power at night.
Throughout history, all great dreams have been considered impossible before they were accomplished. Today, the adventure must continue by realizing a great epic in the service of environmental protection and renewable energies, intended to create enthusiasm around the climate challenges of the 21st century.
Bertrand Piccard, Dorine Bourneton and Michel Tognini embark on an expedition aboard SOLAR AIRSHIP ONE, a 100% electric airship, for the first non-stop round-the-world flight without fuel.
A world tour from West to East flying close to the equator: more than 40 000kms to cover in 20 days at an average altitude of 6 000 meters.
They are raising funds and inviting technical support for their effort. You can subscribe to keep up with the news. The airship will have a crew of three: Bertrand Piccard, Dorine Bourneton, and Michel Tognini. They are aiming to embark on the trip in 2026 and it’s pretty ambitious as they plan to make it without stopping along the way:
With a departure planned during 2026, SOLAR AIRSHIP ONE will fly over more than twentyfive countries, two oceans and several seas. India, China, Mexico, USA, Mauritania, Mali, France… the countries crossed will have the chance to see the future generation of airships.
The engineering details of the design incorporate a number of innovations that will truly advance the state of the art.
SOLAR AIRSHIP ONE is a 151-meter-long rigid airship with a helium expansion volume of 53,000 m3. Its envelope is covered with 4,800 m2 of solar film. Electrical generation comes from 2 sources: the sun and hydrogen. The day with solar collectors, the night with fuel cells.
While the website has a certain amount of information, there are some details that have yet to be filled in. Before Solar Airship One can embark on its round the world tour, it will have to be built and tested. Weight management will be critical — translating design calculations into hardware always turns out to have surprises. Flight testing will be needed to validate computer modeling and the design. The pilots will need to log the flight time needed to build the experience needed to handle the airship under all the conditions it will encounter.
Solar Airship One will have a rigid internal frame — which is what makes it an airship and not a blimp. Blimps hold their shape from the pressure of the gas within their envelopes. While everyone is familiar with the Goodyear blimps, the latest versions actually have an internal frame and are classed as semi-rigid airships. They aren’t blimps anymore. This web page at Goodyear gives a good look at the details of an airship as well the differences between semi-rigid, non-rigid, and rigid airships.
The design of Solar Airship One has several advantages. The rigid frame allows things like motors and other devices to be mounted somewhere besides hanging off the control cabin underneath, as well as supporting the solar panels on top. It makes possible higher speeds, and provides a certain measure of protection for the actual lifting gas envelopes inside.
Getting off the ground
Operating a lighter than air aircraft involves things that don’t come up with airplanes in quite the same way. It’s not a question of just pumping in helium until it lifts off the ground. Managing buoyancy is affected by temperature, altitude, and air pressure. You don’t want maxim lift while your airship is moored on the ground — you want enough to keep it from dragging, but not so much that it has to be tied down to keep from floating away. So what do you do when you want to fly away? (Note — airplanes and helicopters also have to pay attention to temperature, air pressure, and altitude.)
There are a couple of ways to address this in lighter than air vehicles. One is to inflate the lifting ‘cells’ (what they call the gas bags holding helium) with more helium — an option usually only available on the ground. Hot air balloons do it by burning fuel gas to heat the air in the ballon for more lift.
The other is to drop weight, AKA ballast. Traditional balloons would do it by dropping sand bags — and if they ran into trouble trying to stay aloft, everything else they could throw overboard. A more manageable way to do it is by using water for ballast — releasing it to lose weight.
What gets tricky is managing lift and weight. As an airship operates during the day, rising temperatures will cause the lifting gas to expand, creating more lift. Venting gas is one option — but later in the day and into night, cooling temperatures will reduce lift — hence the need to drop more ballast. It can also happen when moving between air layers of different temperatures, like an inversion where a mass of cold air is sitting on top of warm air at ground level, or vice versa.
According to the specs listed for Solar Airship One, they plan to address this issue with a couple of techniques. They call it Autonomous Ballasting, a combination of conventional water ballasting and a compressed-air based system, which presumably means using inflatable cells called ballonets to compress the volume of the lifting cells to adjust buoyancy. They can also be used to adjust the center of buoyancy for Solar Airship One, trimming it for flight nose up or nose down by selectively compressing different cells within the length of the airship.
The airship will be double-walled, to allow better control of the internal temperature of the gas cells to help manage lift as well as providing for anti-icing. The operation of the fuel cells for power at night will be provided by hydrogen — and that will be obtained by hydrolysis from water on board, also reducing weight.
A nightmare for airships is stormy weather. An updraft can lift an airship to a higher altitude where the lower air pressure might allow the gas cells to expand to the point where they rupture. So, one answer is to vent gas to reduce lift as an emergency measure. But, if they get out of the updraft — and especially if they hit a downdraft — they may find themselves dropping from the sky unless they can release enough water ballast to compensate. In a worst-case repeated up and down scenario, it’s possible to run out of lifting gas and/or ballast, neither of which leads to a happy landing.
Validating buoyancy control in actual flight operations will be one of the challenges for the team. The goal is to make the airship as self-contained as possible. As for the issue of storms, modern weather forecasting, satellite imagery, and weather radar will make that much less of an issue than it was for the USS Akron and the USS Macon. While the top speed of the Solar Airship One is not listed that I could find, it will likely have the range and speed to deviate around bad weather.
It should be mentioned this is not the only airship effort under way. Hybrid Air Vehicles has developed the Airlander, which takes a slightly different approach. It manages lift with both lifting gas (helium) and by its shape. Its body is designed to generate lift as it moves forward through the air. The Airlander can get off the ground by using its steerable motors (vectored thrust) to lift up and transition into forward flight. They are also working to go zero carbon. They have orders for passenger versions intended to carry up to 100 people. (They are also developing cargo versions.)
Just make sure you have your ticket.
Why Airships and Why Now?
Why are lighter than air vehicles getting renewed attention? One is technology. There have been big advances — new lightweight materials; computer-aided design, modeling, and control; electric motors for propulsion; modern avionics. All of these promise performance gains that make airships more attractive, especially as countries are looking for ways to reduce carbon footprints.
Infrastructure — airships don’t require miles of runway spread over hundreds of acres. The Goodyear airships are supported by ground crews with a traveling mooring mast system that follows the airships around. Euro Airship is proposing something simpler.
No heavy infrastructure on the ground is required to secure the airship, making it completely autonomous. For regular stops, a simple rotating platform on a sheet of water is sufficient.
While there would still be a need for structures large enough to bring them inside for servicing, they wouldn't be needed at every airport. (There are a few still out there.) This could bring air service to places without requiring massive investment.
(The top of the Empire State Building was originally designed to be used as a mooring mast for airships, as this scene from Sky Captain and the World of Tomorrow shows. It was never actually used that way.)
Noise — Airships can be a lot quieter in operation than jet aircraft, propellor driven aircraft, and helicopters. An electric airship powered by solar panels, fuel cells, or some other power source would be a far better neighbor.
Endurance — Because they don’t have to burn fuel just to stay in the air, airships can operate for hours or even days. It was the reason trans-Atlantic air crossings were first done by airship, and why Solar Airship One is planning to circumnavigate the globe in one go nonstop.
Climate — the Euro Airship project is an attempt to demonstrate that zero-carbon flight is both possible and practical — and that there just might be a transportation niche where airships can fill a real need.
Consider the installation of ever taller wind turbines in remote areas on land. Getting the blades there is a major logistical hassle. How much easier would it be if something like an Airlander could deliver them to an installation site? What about extending regional air service to locations without large airport runways — and without hassles over noise?
It’s a bit bizarre to realize how some of this has roots in the Battle Blimp scenario — but there you are. Let’s not forget Chinese Spy Balloons either.
If Solar Airship One is built, makes the nonstop journey around the world, and proves the concept is viable, it could spark more investment in airships. It would only have a minor impact on the move to get carbon out of transportation overall — here’s another way with larger impact — but it’s still worth a try if only because of what might come of it.
Here’s an illustration giving some idea of the sizes we’re talking about. Note that bigger is better in terms of lifting capacity. As the length increases, the internal volume for lifting gas increases roughly by the cube.
BONUS — Airships in Fiction
The Voyages of His Majesty's Airship, the Flying Cloud (2 book series) is a Kindle edition of what was a weekly serial adventure series on the Internet. (Alas, it’s no longer available there.) Author Paul Gazis combined illustrations with a story set in an alternative universe to paint a picture of a post World War One world where airships reined supreme. With some inside jokes, thrilling adventures, and some science fiction aspects, Gazis also provided some fascinating practical details about what it would actually take to operate an airship.
The Big Lifters by Dean Ing is a 1988 techno thriller. It appears to be out of print, but copies are available out there. (The blurb at the link is incorrect.)
The story is about innovator tycoon John Wesley Peel’s efforts to develop a big lifter — a large airship, similar in concept to the Airlander. His object is to get Big Rigs off the highways. He’s started by setting up a freight brokerage business, getting as much long-haul traffic from trucks onto rails as possible. (Rather like Solutionary Rail’s Moonshot Modeshift.) He’s marketing a line of short haul trucks to handle the ‘last mile’ between rail and destination — and his airship is intended to take away high value truck loads to further decimate the big rigs.
If that wasn’t enough of a challenge, the story also brings in a trucking union boss determined to protect his industry, a Middle Eastern terrorist operation trying to take out America’s best and brightest — and a group of employees looking to piggyback off Peel’s efforts behind his back with their own plans to revolutionize transportation from ground to orbit. The book holds up surprisingly well and is even more relevant in some ways to where we are now.