They are everywhere, “spies” above the United States, “scientists” for Météo-France, even “doctors” on behalf of the national center for space studies (CNES). Balloons, which were widely used during the Cold War, were not finally discarded with the advent of satellites and drones. As proof, the Chinese aerostat (and the three other aircraft shot down recently by the United States) demonstrated in February that the balloon had never left the panoply of the perfect spy.
They are even at the heart of research that is already well advanced across the Atlantic. There Darpa, the agency that works on technologies for military use within the United States Department of Defense, has been working for several years on a balloon that could stay in the same place, without being tossed about in the wind. Which would be a technological feat. In France, it is the “balloon division” of Cnes which is closely interested in these “maneuvering balloons”, according to Vincent Dubourg, deputy director “balloons”. “We hope to have a small demonstrator within two years that we are developing with Hemeria. This is of interest to scientists but also to the military,” he explains to 20 minutes.
Balloons that must be registered
The stratosphere, which is between 12 and 50 km above sea level (roughly between airspace and space itself) has therefore become a new playground for companies and industrialists. So how do these balloons, which multiply at the speed of the wind, “circulate” there? The area is less regulated than the airspace but aircraft cannot do anything there either. “We comply with all air regulations, which are governed by the International Civil Aviation Organization (ICAO). There’s the rules of the air, it’s appendix two appendix five of the Chicago convention of 1944 who says that the balloons, depending on the size and especially according to its payload, must have a certain number of accessories on board to have a signature”, recalls Vincent Dubourg. The “air scientists” must therefore be registered and have a radar transponder allowing their presence to be signaled to aircraft in the zone ranging from 0 to 18 km altitude.
For the zone ranging from 20 km and up to 100 km, “it’s more vague”, concedes Vincent Dubourg: “When you read article eight of the Chicago convention, it is written that any unmanned object, even in that area, is supposed to request overflight clearance. That’s what we do, we at Cnes cannot fail to comply. Quite simply because each year, its teams based in Toulouse and Aire-sur-l’Adour (Landes) launch around forty balloons (from light weather balloons to larger ones that can tow more than a ton of load) with five or six experiments on board. A know-how in design and operation that lasts for sixty years.
These balloons are used to measure components of the atmosphere, in particular the ozone layer, to detect water vapour, methane or even carbon dioxide using onboard instruments. But also the dynamics of the atmosphere. Carried by the winds, these state-of-the-art facilities make it possible to learn more about their speed and strength, in order to improve weather models, among other things.
Nearly 50,000 balloons a year launched by the American weather services
On his side, Meteo France must also respond to the Chicago convention. It must be said that the weather expert releases several weather balloons each day in latex from its ten automatic radiosonde sites and its five manual radiosonde sites in Overseas France. They rise in two hours to an altitude of 30 km and drift up to 100 km from their starting point, before bursting and falling to the ground using parachutes. “The instruments on board measure the temperature and humidity and send the measured data to the ground station”, indicates to 20 minutes the national meteorological service. And thanks to GPS positioning, we can deduce the speed and direction of the wind.
Same rules on the side of the US National Weather Service which launches nearly 50,000 balloons every year, while multiple measurements are taken every day and all over the world by other weather services, in nearly 900 locations.
Without forgetting that these aerostats are not only used for the weather. Those from Cnes have, for example, already mounted astronomical telescopes or models of space shuttles in the stratosphere to study their aerodynamics. “We also tested the parachute deceleration system to land on Mars as part of the ExoMars program, dropping it over Sweden in an almost deserted area,” says Vincent Dubourg. And the head of Cnes to see other horizons open up for his balloons: “we are working with the National Institute of Health and Medical Research (Inserm) in Lyon to look at the effect of radiation on stem cells , on the living. We expose stem cells above the atmosphere, protected by various shields, and we look at the effect of radiation from the sun, UV rays and X and gamma radiation from the universe on these stem cells in order to predict term how to better protect airplane pilots behind their cockpits, as well as astronauts. »
And beyond these scientific projects, new commercial activities are emerging. The Fying Whales company is thus considering using balloons to transport freight and give the possibility of conveying loads inaccessible by road, such as towing wood where a truck could not reach. Tourism in the stratosphere thanks to balloons, less polluting and expensive than a rocket ride to the International Space Station (ISS), is also in vogue. In Toulouse alone, two companies, Stratoflight and Zephalto, are in the running.
Obligation to declare oneself to the countries overflown
Plugs could therefore soon be created in the stratosphere, knowing that Thales Alenia Space also intends to send its Stratobus there, an autonomous airship stratospheric balloon which will be able to embark on border surveillance missions, environmental hazards (forest fires, etc.) or more telecommunications equipment. All this in addition to the more expensive traditional satellite activity.
In 2021, during a campaign to release 17 balloons from the Seychelles which were to circumnavigate the globe, Vincent Dubourg’s teams had to request overflight authorization from 96 countries. Requests which do not encumber the countries releasing their “spy balloons”. Especially since if the transponder-radeur of the machines is cut off and the release is done at night, these “spies from the air” can go unnoticed and never be tracked. Until they are overtaken by the patrol… like the famous “Chinese balloon” which deviated from its trajectory according to Beijing.
“From the ground, we see the missiles leave, we know how to detect them, we also know how to see the rockets and we know where the military satellites pass. A ball, if you don’t know where it is thrown from, it can be thrown from anywhere. There aren’t too many thermal signatures, apart from the big ones that you can see them pass, ”recognizes Vincent Dubourg. With the appearance of new desires for commercial companies, the Cnes expert knows that the regulations for flights in the stratosphere could be reviewed and corrected. The head of the “balloon division” just hopes it won’t come at the expense of science.