Never used for manned missions. It’s been used quite a few times (well over 100, by my count) for unmanned capsule recovery.
Not a lot. The higher the pressure the more compressed gas is in the balloon and the heavier it will be. You want your balloon to have just enough pressure to hold its volume.
I have never studied anything to do with gas flow, but with 20 x 20mm holes, and say 1 psi pressure differential, using online flow rate calculators I get figures that would see a balloon deflate fast enough not to make it from Canada to Europe. But I’d be the first to admit that I don’t know what the hell I’m doing when it comes to gas flow. And maybe the pressure is way lower than 1psi.
I guess the problem is that cannon are designed to punch relatively small holes in hard material. Flechettes designed to make big holes in fabric would see the balloon come down fast.
It’s much, much smaller than that. There is such a thing as a “superpressure balloon” that does have non-negligible internal pressure, but they are only about 0.026 psi. Regular high-altitude balloons are less than even that (basically zero).
The balloon that was shot down off the coast of SC last week was reportedly 200 feet in diameter. Assuming something close to a spherical shape, I came up with a volume of 4.2 million cubic feet.
Very, very little. They’re usually made of polyethylene, and to keep the weight down, that material is whisper thin, on the order of 0.001 inches. With a tensile strength of 4000 psi and a balloon diameter of 200 feet, the most pressure it could possibly contain would be about 0.007 psi.
Also, they probably don’t want it to drop but drift slowly down so that it doesn’t get busted up.
The missile that shot down the first one cost the taxpayers $400,000 (not counting the cost of the plane to deliver it, fuel for that plane, paying the pilot, etc.).
So you could say we are throwing money at it.
If I were designing a system to take down a high altitude ballon, I’d start with something like a bolas. Add enough weight and it’ll come down.
I was at some sales event in a mall years ago, where they were handing out helium-filled balloons to the kids. The ceiling of the mall - inevitably - was covered with a dozen or two stray balloons. One of the helpful sales staff had a balloon on an extra-long string with double-sided tape on top. He maneuvered under a stray balloon, bumped it, and pulled down the stuck-together pair and handed the balloon to the next passing child. This way they slowly cleared their airspace of UFO’s (Unclaimed Floating Objects).
I suppose you could construct a dirigible with a claw that would latch onto a stray object then vent its gas, dragging both objects down with a certain amount of navigation capability. Use hydrogen, helium is expensive.
Some kind of parasitic ballast? Interesting but still doesn’t solve the hard problem of safely approaching and attaching to the target, only changes the method of forcing it down. And I don’t know how much ballast you can reasonably loft without making your attack system much larger and less maneuverable than the target.
There is no money waste. We (US) fire dozens of these missiles every year in training and testing. The missiles all have a shelf life and a service life. As that runs out, it’s cost effective to use an expiring asset as training, or in these cases, an actual shoot down rather than simply destroying the missile as unserviceable. The pilot/aircraft time also is not wasted. It’s training, perhaps unplanned, but involves every one in the chain; ground crew, aircraft tankers, radar and communication specialists, other aircrat and countries. Nothing was “wasted”.
Size of the attack balloon would logically be comparable to the size of the target. (so, make them in Small, Medium, Large, and XXL.) It could be flown to the locale and inflated on site. I would suggest long claws and a clamping motion, I’d even call it Venus Flytrap or Edward Scissorhands. It sticks a number of prongs into the balloon then closes them together like a pair of gripping claws. The only problem would be if the material gave way so the target balloon loses its attacker by losing a huge chunk of the skin. Since the whole point is to take down the balloon, the only need is to get a good grip. Then, deflate the attack balloon so the whole lot comes down. Weigh commensurate with target capabilities. Punctures in target are a bonus.
Unless the target balloon is highly maneuverable, it really doesn’t matter. Presumably something with the maneuverability of the Goodyear Blimp, but a 80,000 foot ceiling, would do a good job. If the target is faster or more evasive than that, then use a missile. It’s not really “just a balloon”. It’s a threat.
Similarly, there’s a mall downtown with an extremely high atrium. I don’t know if there was a balloon vendor in the mall, but some ended up in there anyway. I once saw a worker with a large balloon on a very long string, with a pin on the top of it, clearing out accumulated balloons.
Though that might be less practical, here.
Yes, my thought for more durable weather/research balloons would be to ram it with two rows of long sharp points, Then close those rows together to get a solid grip on the fabric.
Sharkpedo?
It does seem odd that such a method hasn’t been developed. I’m sure there are a lot of ideas that might plausibly work, and I wonder why none of them apparently exist.
My thought, for instance, would be to send numerous much smaller balloons with similarly much smaller payloads; each of these payloads is basically some sort of gripping device designed to secure itself to a balloon or the payload on the balloon you’re trying to capture. As more and more of these things attach themselves, the balloon inevitably descends. The payloads could even have propulsion of their own, to allow the capture to be guided and therefore land precisely where they want it.
It’s not something you could likely cobble together in a matter of days, but it’s certainly something that appears to be feasible, which makes me wonder why it hasn’t been done.
That said, I am also confused as to the purpose of a spy balloon from a country that has satellites. I don’t understand what advantage the balloon gives over satellites, which are able to capture images of amazing detail at ground level.
Speculation: if your military playbook includes shooting down your adversary’s satellites to blind them at the start of a hot war, this creates a debris cascade which likely destroys your own satellites, so it’s smart planning to develop experience with a backup option.
How do you control your smaller balloons? You’ll be lucky if any of them get within gripping distance of the target balloon. Most likely they’ll all go off in the wrong direction, especially if the target balloon is at high altitude. Or maybe they’ll grip each other.
During the WWI terror bombing of London English pilots found it very difficult to down a dirigible kept aloft with bags of hydrogen using special machine gun bullets that emitted a spinning spray of burning phosphorus.
No. They’re currently unavailable.