High-Altitude Balloon FAQ March 2023


I see a balloon flying in the sky. What is the purpose of this flight? 

The current flight is coordinated very closely with SNC and the U.K. Ministry of Defence (MOD) as part of the Project Aether Flight 2 Assessment Phase contract. SNC’s HAB provides global, persistent and uninterrupted communication capabilities at higher altitudes in near real-time.

The flight includes two balloons that will launch from the Island of Hawaii. They will travel approximately 4,000 nautical miles (nm), perform station-keeping demonstrations, and will safely land within the United States. The purpose of the flight is to explore how to effectively operate in the stratosphere using high-altitude, long-endurance unmanned air systems.

You are launching near Waimea, next to Mauna Kea. How will you ensure protection of this important cultural site?

We recognize the grave importance of Mauna Kea as well as other sacred sites on Hawaii and surrounding areas and can assuredly say we expect no impact whatsoever to Mauna Kea, Mauna Loa or other sites in the region. We understand the importance of the native Hawaiian culture and are dedicated to treating the land, water, air and wildlife with the utmost respect. There will be no interaction between the mountains and the balloons, and the launch team has no need to traverse either mountain, interact with local wildlife or with nearby livestock.

HAB launches are low impact, particularly when compared to traditional aircraft and certainly in comparison to other near-space platforms. In addition, HABs are far more environmentally friendly than other methods of flight and/or motorized transportation, requiring only helium and/or hydrogen in addition to the balloon itself. The balloons used in this flight will be filled with helium, a non-flammable and non-explosive lift gas.

What if the balloon lands in the ocean?

All balloon assets are fully trackable. Should a balloon encounter a situation that results in ocean landing, resources will be deployed to try and recover any and all balloon remnants. This scenario is extremely unlikely. Furthermore, no toxic chemicals are used on HABs that could cause damage to water or ocean life.

Should the balloon land in an area populated by livestock, the same conditions apply.

Why was Hawaii selected as the launch location?

In order to achieve Project Aether’s objective of travelling at least 4,000 nm, a launch from the Hawaiian Islands is required. The continental United States is roughly 2,000 nm from coast to coast, so adding the distance from Hawaii to California increases the distance by the needed 2,000 nm.

What if something goes wrong with the balloon or the test?

The HAB is constructed of Linear Low-Density Polyethylene, an extremely strong and lightweight blended plastic material that – even if punctured – will not immediately deflate. This provides time to navigate the balloon to a safe area for recovery. Due to materials used in construction and the minimal supplies required to launch a balloon, incidences or other failures surrounding launch are generally rare.

Is the balloon being used to spy on American citizens? What information is being collected?

Absolutely not. This demonstration flight will be equipped with a basic communications payload. Any information gathered is used for mission-specific purposes only and can never be given or sold for other uses.

Will the government shoot down this balloon?

No. This test flight has been coordinated in concert with federal, state and local authorities before, during and after missions. These entities are fully aware of the planned flight trajectory.

 Is this flight connected to the Chinese government?


General Overview Questions:

What is a high-altitude balloon/stratospheric ballooning? 

High-altitude balloons (HABs) are large balloons that are able to navigate the stratosphere at altitudes ranging from 50,000 – 80,000 feet. They are frequently used to carry payloads of remote sensing and communications systems that can be used for a variety of purposes ranging from supply-chain tracking and utility line inspection, to wildfire and storm tracking, communications/internet connectivity, climate change research and many other purposes.

Is this technology safe? 

Yes. These are “zero-pressure balloons” meaning it will not explode or quickly let out air if punctured. Should the balloon be damaged, it would take hours to come down, providing ample time to make a calculated decision about a safe and secure landing location. All gases that may be released through a hole or otherwise are completely safe and non-toxic.

How do you secure permission to fly over specific areas?  

Launch and flight patterns for High Altitude Balloons are coordinated very closely with several government entities – federal, state and local – before, during and after all flights. In the United States, that means filing flight plans with the FAA and any other appropriate authorities and monitoring communications and airspace to gain clearance for flight. The balloons also carry flight tracking transponders that allow the necessary government entities to identify and track balloons in real-time throughout their entire flight.

While most operations happen above 50,000 feet and do not impact commercial air travel, launches are coordinated with local airport authorities to gain proper clearance as it launches and ascends through commercial airspace before reaching target altitude. Additionally, constant communication is maintained with the FAA and local airports during all flights. The safety of the general public is a top priority, which is the reason flights are coordinated so closely with the appropriate authorities.

How are HABs controlled?  

A zero-pressure balloon lifts the system into the stratosphere while the smaller, super-pressure ballast balloon creates mass to counteract the lift of the zero-pressure balloon, facilitating navigation. 

In the stratosphere, there are generally four directional winds. Controlling altitude allows for free navigation in the stratosphere (accessing winds that go East, West, North, and South), or what is known as station keeping–the ability to remain over an area for several weeks at a time.

What are the balloons made of? 

Linear Low-Density Polyethylene, a lightweight, fibrous plastic that is extremely strong. It is a reusable material that can withstand the harsh environment of the stratosphere. These can be made of different proprietary blends. 

How are the balloons and payloads recovered at the end of the flight? 

The payload separates from the balloon and is flown back down to a safe, secure location via a steerable parafoil. The balloon gently descends back to Earth where both it and the payload is recovered by the operations team.

For additional questions please email comms@sncorp.com.