Unmanned balloons, also called balloon aerostats or balloon drones/unmanned aerial vehicles (UAVs) are popular types of drones used for a variety of tasks in several industries.
These types of drones were once some of the most popular drones used but became lost in the rapid development of technology that brought us improved versions and new types of UAVs such as fixed-wing UAVs, rotary-wing UAVs, and even hybrid fixed-wing/VTOL UAVs.
What are unmanned balloon aerostats?
Unmanned balloons are types of unpowered aerostat drones/unmanned aerial vehicles (UAVs) that generate lift using lifting gas within an envelope while carrying various payloads.
These types of aircraft are considered lighter-than-air UAVs. To avoid confusion, we will be referring to them as unmanned balloon aerostats.
- How Do Unmanned Balloon Aerostats Work?
- What Are The Types Of Unmanned Balloon Aerostats
- What Are Unmanned Balloon Aerostats Used For?
- What Parts/Components Make Up Unmanned Balloon Aerostats?
- What Are The Advantages & Disadvantages Of Unmanned Balloon Aerostats?
- What Are Some Examples Of Unmanned Balloon Aerostats?
- Conclusion
How Do Unmanned Balloon Aerostats Work?
Unmanned balloon aerostats use lifting gas (typically helium) as it’s typically less dense than the air outside that is contained within an envelope to obtain buoyancy and float in the air while carrying various payloads depending on the task it is intended to be used for.
Buoyancy is a force typically found in fluids where an object of a certain weight will either rise, float, or sink depending on whether it is less dense (rises), equal in density (floats), or denser (sinks) than the fluid it’s in.
The pressure exerted on the object will typically increase the deeper it sinks.
Check out our full post on unmanned aerostats where we dive into how they work, their types, applications, parts/components, advantages/disadvantages, propulsion systems and examples:
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The same concept applies to unmanned balloon aerostats replacing fluids with gases.
Unmanned balloons won’t inflate their envelopes fully as the higher they go, the lower the pressure outside gets which will cause the lighter-than-air gas within to expand.
Once the pressure within the envelope is equal to the pressure in the surrounding air, the aerostat will have reached what is called the pressure height.
Flying higher than this will increase the risk that the envelope ruptures as the materials used to create the envelope are only so strong.
Helium is used as lifting gas as it’s non-flammable, effective and safe. In the past, they used hydrogen which is far more dangerous as it’s flammable. Some still can but the use of hydrogen in aerostats in certain countries is actually banned.
Their envelopes are often non-rigid, relying on the internal pressure from the lifting gas within them to maintain the shape of the envelope. They can however also have a supporting structure to aid in maintaining the shape of the envelope such as a keel.
The devices/equipment on-board the balloon aerostat can be powered using power sources such as batteries or fuel cells, and can also be directly powered using powered tethers in the case of tethered balloon aerostats.
Tethered unmanned balloon aerostats have a grounded anchor point that they attach to in order to stay at a fixed location in the air.
Check out our post where we dive into what drone tethers are, the different types, uses, advantages/disadvantages, materials they’re made of, costs, examples and more:
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These vehicles either have an integrated winch system or one that’s separate in order to adjust the tension and length of the tether.
Unmanned balloon aerostats often have ground/mobile control stations where the operators can receive and measure data gathered from the aerostat. This data can be sent wirelessly using radio waves or through a powered tether.
The size and shape of the main envelope will impact the maximum flight time, range, and altitude the balloon can attain. The two most common designs include spheroid and oblong envelopes.
No aerostat can fly forever as the lifting gas stored within the main envelope will continuously leak. They need to be refuelled with lifting gas for extended use.
For landing and docking, unmanned balloon aerostats typically have systems in place where the balloon can land and deflate and vehicles that the balloon along with the equipment used with it can be stored and transported.
What Are The Types Of Unmanned Balloon Aerostats
There are a few types of unmanned balloon aerostats excluding categorising them by the material used for their envelopes or the shape their envelopes make.
Here are the 2 main types of unmanned balloon aerostats:
- Tethered unmanned balloon aerostats
- Free-floating unmanned balloon aerostats
Tethered unmanned balloon aerostats are types of unmanned balloon aerostats that are tethered to a ground/mobile control station. These tethers can be powered or unpowered depending on whether they both transmit data and supply power or not.
Free-floating unmanned balloon aerostats are types of unmanned balloon aerostats that are untethered and use surrounding wind as propulsion while generating lift using buoyant lifting gas.
Take note that unpowered in this sense refers to the fact that they do not have propulsion systems used to propel and steer the drone.
What Are Unmanned Balloon Aerostats Used For?
Here are 4 applications for unmanned balloon aerostats:
- Exploring the atmospheres of other planets
- Measuring weather patterns
- High-altitude ISR
- Extending the reach/capacity of communications systems
Check out our full post on aerostat drone applications where we explain what each use case entails and how unmanned aerostats are used in them:
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What Parts/Components Make Up Unmanned Balloon Aerostats?
Unmanned balloons are made of an envelope, basket/gondola/capsule, communications system, payload, often a tether, and sometimes a power source if needed.
The envelope is a sack made of fabric that contains the lifting gas enabling an unmanned balloon aerostat to fly.
These can have additional wing-like fabrics adding to the envelope which can add control and stability.
A basket/gondola/capsule is a compartment typically suspended beneath the main envelope of an unmanned balloon aerostat that holds the payload and often other important components enabling the drone to function.
The communications system is the system enabling an unmanned balloon aerostat to send and receive data to and from the operator/s. This data is typically the information gathered by the onboard payloads.
Payloads include any additional weight the unmanned balloon aerostat can carry that is not essential for it to function other than its base weight.
All unmanned aerostats can carry various payloads of various weights including but not limited to electro-optical/infrared (EO/IR) sensors, radar, radiosondes (telemetry instruments that measure pressure, wind conditions, altitude, temperature etc) among many others.
These payloads are often attached underneath the main envelope using cables and capsules.
A tether is a cable/cord that can either be powered or unpowered serving the primary purpose of connecting the drone to a fixed/mobile location.
Powered tethers can additionally provide power to the onboard payloads and can send and receive data gathered by these payloads to the operator/s.
Powered tethers are commonly referred to as ‘live’ tether systems whereas unpowered tethers are commonly referred to as ‘dead’ tether systems.
A power source is any device used to provide power to the UAV. This includes powered tethers, batteries, fuel cells (FCs) etc.
They are also typically required to have lights and radar reflectors and to follow certain rules that vary by country in order to legally operate and prevent mid-air collisions with other aircraft.
What Are The Advantages & Disadvantages Of Unmanned Balloon Aerostats?
We’ve split up the advantages and disadvantages into their own separate sections.
Unmanned balloon aerostat advantages
Here are 4 advantages of unmanned balloon aerostats:
- They typically have very high payload capacities
- They are cheaper to operate than other types of UAVs
- They can fly for very long periods of time
- They can be made very durable capable of widthstanding rough weather conditions
Unmanned balloon aerostat disadvantages
Here are 5 disadvantages of unmanned balloon aerostats:
- They cannot be steered
- They are very slow
- The helium used for lifting gas is expensive
- Tethered balloon aerostats have a limited operating range
- They have to be grounded/anchored in order to provide a resupply of lifting gas in order to extend its operating time
What Are Some Examples Of Unmanned Balloon Aerostats?
Here are 4 examples of unmanned balloon aerostats:
| Name | Manufacturer | Type |
| Skystar 180 | Aeronautics Defense Systems | Unmanned Balloon (Tethered) |
| Thunderhead Balloon Systems | Raven Aerostar | Unmanned Balloon (Free-Floating) |
| WASP (Winch Aerostat Small Platform) Aerostat | Drone Aviation Corp | Unmanned Balloon (Tethered) |
| Skystar 300 | Aeronautics Defense Systems | Unmanned Balloon (Tethered) |
If you’d like to discover who the best drone companies are in the world for the consumer, commercial and military drone markets and some fun facts about them, we have a full post on this topic below:
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Conclusion
These types of unmanned aerostats are already being used in several industries and may become even more popular. They may soon even be rivalling other popular types of aerial drones in the military, institutional, and commercial UAV markets.
If you’d like to learn more about this technology, we highly recommend you check out our full post on what unmanned aerostats are and how they work.
