In the age of stealth drones and advanced satellites, the presence of a "spy balloon" in the American sky is almost an anachronism.
On Thursday February 2, the Pentagon indicated that it was tracking the movements of a high-altitude flying machine, stating that it had "
no doubt that it came from China
".
The United States has sent F-22 Raptor fighter jets to contact it, but for the moment does not want to risk shooting it down because it is "
big enough for the debris to cause damage
" .
But what is this stratospheric balloon the size of three buses doing in American airspace?
"
We take measures to protect ourselves against the collection of sensitive information
", simply indicated a senior American defense official, insisting on "
the limited added value in terms of information collection
".
Balloons from World War II
The use of intercontinental balloons at high altitude, to spy or carry out an attack, is not new.
Japanese scientists were the first to exploit them for military purposes in 1944, according to
Popular Mechanics
, a science and technology magazine.
They were then used to drop incendiary bombs.
The concept was then taken up during the Cold War.
If the machine seemed once out of fashion, the Americans are using it again today, in a much more sophisticated form.
Almost undetectable
In the United States, the company World View develops this type of device for the Pentagon and NASA.
Their balloons, dubbed Stratollites, can house thermal cameras, radars, radio frequency sensors and solar panels.
Recent advances in the miniaturization of electronics also allow balloons of this type to "
weigh less and therefore be smaller, cheaper and easier to launch
," Griffith Asia expert Peter Layton told CNN. Institute in Australia and a former officer in the Royal Australian Force.
Read alsoWar in Ukraine: Russia discreetly develops its spy satellites
They are also almost undetectable for anti-aircraft defenses.
Capable of flying more than 20 kilometers high, well above the usual flight paths of an aircraft, "
they have a very low thermal signature and almost zero emissions
", explains, still to CNN, Blake Herzinger, expert in Defense Policy at the American Enterprise Institute.
More mobile and autonomous than drones and satellites
Spy balloons thus represent an interesting alternative to drones and other stealth aircraft.
The latter are indeed quickly limited by their flight duration.
"
Even with the Global Hawk
(main American strategic reconnaissance drone, editor's note)
, you only get an autonomy of 20 hours of flight around the target area, and even less if the travel time is long
", underlines with from
Popular Mechanics
Justin Bronk, a member of the British think tank Royal United Services Institute (RUSI), specializing in defense and security.
Read also"Shards of the world" N ° 10: The "reset" of China
These machines also have advantages over satellites, which China is not without.
In particular, they are much more mobile than satellites in low orbit, which are subject to the rotation of the Earth, but also than satellites in geostationary orbit, which rotate at the rhythm of the Earth but therefore only concentrate on a specific point.
Balloons can move with the wind and be guided from a distance, but also remain stationary for many hours.
"
We believe these devices have the potential to be a game-changer because they are an excellent long-duration surveillance platform
," Admiral Kurt W. Tidd, head of U.S. Southern Command
, told
Popular Mechanics .
What can he spy on?
After flying over Canada, the spy balloon was detected over Montana.
This state, along with its neighbors, is home to US intercontinental ballistic missile silos and strategic bomber bases.
But the device can also be used to “
retrieve signals intelligence and examine mobile phone traffic and radio traffic
,” retired US Air Force colonel Eric Burnett told CNN.