Ukraine is attacking Russia with a new type of long-range drone: a balloon dropping mortar bombs from high altitude. These simple, low-cost devices are controlled by sophisticated off-the-shelf electronics complete with satellite communications. Recent advances in software and better understanding of wind patterns mean such balloons can directed with considerable accuracy over long range.
Experts note that the Ukrainian balloons have a number or surprising features. What may look like a trivial harassment tool could be an ingenious, asymmetric weapon to boost Ukraine’s strategic strike capability.
Russian Balloon Reports
Back in February 2023, Ukrainian defenders brought down a number of Russian balloons. These appeared to be standard weather balloons carrying radar reflectors which drifted towards Kyiv at altitudes of up to 11,000 feet, and seem to have been used as decoys to confuse defenders during drone and missile attacks.
This March, the Russians reported they were shooting down Ukrainian balloons, which appear to be larger and more sophisticated – and armed.
“For the first time, the Armed Forces of Ukraine launched a series of weather balloons with explosives deep into Russia,” claimed state media outlet MASH.
According to the MASH report, one balloon came down in a forest near the village of Novaya Slobodka and another was destroyed in the Kursk region. Some balloons carried mortar bombs and others carried radar reflectors, believed to be to make the balloon look like an attack drone and presumably draw fire from Russian air defenses. According to MASH, each balloon also has a GPS tracker, ballast, batteries, and control electronics with the attack co-ordinates programmed in to them.
One image from a downed balloon shows an 82-mm mortar bomb, a 6.5-pound fragmentation/blast weapon, another shows what looks like an improvised weapon of similar size. MASH mention an 81mm mortar bomb, which is either a typo or an indication that a third type of weapon is in use.
But the rest of the balloon is more mysterious.
Superpressure, Zero Pressure, Latex Or Thermal?
Most sources the sheet of thin material is the balloon itself, but this doers not seem likely.
“The black material isn’t a balloon, it looks more like an over-sized descent parachute,” balloon expert Chris Hillcox of Near Space Photography told me.
Hillcox notes that there are three main types of balloon – superpressure, like silver party balloons filled with pressurized gas, zero pressure where the balloon envelope expands as it rises, and the common white latex balloon used by meteorologists which reaches a certain altitude before bursting. The material does not look like any of those.
“There appears to be cord coming from the base. If this is the case then there is no balloon left and one can’t conclude anything about the balloon. It is very easy to rig up a cut off, a device separating a payload from the carrying balloon. So they could have used latex balloon, or small zero pressure balloon or even super pressure balloon.”
He notes that the intact state of the material does not look like a balloon which has either failed or been shot down, adding weight to the parachute theory.
Steve Randall of balloon suppliers Random Engineering Ltd says that the device looks home made and does not resemble any normal weather balloon. He suggests that the black material could possibly been the type of plastic used as bin liners and that this might be the envelope of a thermal balloon – a rare type which absorb solar energy to warm up and gain buoyancy. Randall notes that such material could in principle be used for a zero-pressure balloon but that in practice clear plastic is almost always used for such envelopes.
Both suggested the plastic bottle is likely there for ballast. It may be filled with liquid with a small hole, so it gradually loses weight to compensate for loss of lift by gas leaking from the balloon envelope.
Electronic Teardown
Balloon bombs can be cheap, simple weapons. The earliest known type were invented by Austrian engineer Franz Von Uchatius in 1849 during the siege of Venice. Land-locked Austria had no warships, so to bombard the city Uchatius fitted hot-air balloons with small bombs, which were released on command “by means of a long isolated copper wire with a large galvanic battery placed on the shore,” according to a contemporary report in Scientific American.
This balloon attack was the first use of armed drones as well as the first ever air raid, but the small bombs were not notably successful. Balloon bombs have been reinvented many times in the last 175 years, and were notably used in WWII when Japanese FuGo fire balloons hit the U.S. mainland from thousands of miles away (making them the first intercontinental weapon), and the Allies Operation Outward against occupied Europe. More recently Hamas have use balloons for incendiary attacks from Gaza. While their effects are generally limited, such balloons place a much heavier burden on the defneder than the attacker.
The Ukrainian version is considerably more advanced than previous models. As the Russian reports indicate, it has a range of hundreds of kilometres at least; similar hobby balloons regularly circumnavigate the Earth in the jet streams. DanielR, a physicist and OSINT analyst on Twitter/X, carried out a detailed study of the electronics seen in pictures from Russian sources. He notes that these show a plastic bottle above a container with the control electronics followed by a tracking device with the munition underneath.
“The munition is supported by a string that passes through a wire loop. This wire loop is an important part of how this system works,” notes DanielR. “A Bluetooth module is the brains of the balloon. This module can enable a relay to pass current through the wire loop that holds the string for the munition. The loop will become very hot melting or burning through the string thus releasing the munition.”
The Bluetooth microcontroller)module appears to be a commercial ESP32-H2-Mini-1 by Espressif. There is also a $20 GPS GP1818MK module. More interestingly, beneath this is a tracking device, a $130 Spot Trace.
“This device sends GPS location data directly to communication satellites. Ukraine would receive this location information at intervals of a few minutes depending on the tracking plan,” notes DanielR.
He says the tracker is the most expensive part of the balloon. Hillcox agrees, noting the entire setup could cost around $1,000, depending on the type of balloon involved and whether it was filled with expensive helium or cheap but dangerous hydrogen.
“If you use hydrogen then the price drops but the risks rise,” says Hillcox.
Radar Plus GPS
Without the radar reflector the balloon would be highly stealthy and difficult to pick up on radar. But the Ukrainians probably want it to be seen. At altitudes of 30,000 feet or above, the only way to bring the balloon down is with an expensive surface-to-air or air-to-air missile, which would be a good exchange.
The reflector may also allow the Ukrainians to track the progress of the balloon and compare the data with what the GPS tracker is sending. This could help map areas where GPS is being jammed or spoofed to improve the accuracy of their drone strikes.
The parachute release may also drop the GPS tracker in place to monitor GPS interference over a prolonged period.
The GPS tracker could be used in an arrangement for balloons to be steered with increasing accuracy. The U.S. military and other have recently been using balloons which can change altitude to take advantage of winds blowing in different directions. As the name ‘stratosphere suggests’, at high altitude the atmosphere is stratified with wind in different directions at different altitudes, so moving to the right height can send a balloon in almost any direction desired. This approach was also used by Google’s now-discontinued Project Loon. Whether the Chinese spy balloon shot down last year could navigate precisely is a matter of some debate.
Some balloons can now navigate over a given spot and orbit it for a prolonged period. The Pentagon’s COLD STAR – Covert Long Dwell STratospheric ARchitcture – is a highly classified platform harnessing this technology. Ukraine is unlikely to be using anything so sophisticated, but may take a similar approach so their balloons do not drift at random.
Stratospheric navigation currently has an accuracy of miles rather than feet, and dropping a bomb from high altitude adds to the inaccuracy. However, dozens or hundreds of balloon bombs might be enough to score hits on a large target like a gas storage facility or an airbase. The Japanese launched several thousand FuGo fire balloons in WWII costing a few hundred dollars each, many assembled by schoolgirls in rudimentary workshops. This type of mass threat would force the Russians to engage the balloons.
Release The Balloon Interceptors
Bizarrely enough, Russia is the only country to have possessed a specialized aircraft for shooting down balloons. The M-17 Mystic was a high-altitude aircraft designed to intercept American spy balloons. These were a problem for the Soviet Union from the 1950s onwards as the CIA and others launched large numbers of camera-carrying ‘weather balloons’ in attempts to get a glimpse beyond the Iron Curtain in the days before satellites. The M-17 could reach of 70,000 feet and was equipped with twin turret-mounted 23mm cannon firing special projectiles to shoot down balloons.
When the balloon threat faded, the M-17 was repurposed for reconnaissance and high-altitude weather research. But as increasing numbers of Ukrainian balloons take advantage of the prevailing wind to cross Russian airspace, potentially crossing the entire country, Russia might need to start dusting off its plans for anti-balloon defense. In addition, that is, to dealing with the threats it faces from a growing list of other Ukrainian long-range weapons.