“[Balloons] have extremely small radar and thermal cross sections, making them relatively invulnerable to most traditional tracking and targeting method".

https://www.thedrive.com/the-war-zone/why-shooting-down-chin...

On the other hand, a $400,000 missile can bring down a $100M fighter or a $1B bomber. The economics of modern warfare can take a while to get used to.

Using expensive missiles is a form of power projection. It tells the adversary we are willing to outspend them 1000 to 1. Sometimes there is a logical answer to why we are spending too much money.

Also bullets work just fine, they just cause slow leaks that could take hours to ground the craft, which might not be what you want.

Arguments around force projection are certainly going to be popular inside the beltway. At a certain point the deficit does become a national security concern, and announcing to our adversaries that they can exacerbate that timeline with incredibly inexpensive balloons is no longer "projecting" anything that resembles "power"

Jingoism isn't power.

My brother in Uncle Sam, we’re only one week into this “crisis”, which is widely overinflated. China is posturing about balloons in its own South China Sea, while America is gassed up about balloons over the Alaskan heartland. This is the posturing phase, and a missile or three is a rounding error in the US defense budget. I don’t see the economy losing buoyancy yet.

Nevermind that the training value of firing a live AIM-9X at a live but odd target is probably worth more than $400k on it's own.

Bullets (20 mm cannon shells) could work to an extent. But they are short ranged and require the fighter aircraft to get close to the target at a high closure rate. This creates some risk of a mid-air collision. Using guided missiles is much safer.

Canon rounds aren't great for balloon targets. It's quite likely that a balloon doesn't offer enough resistance to trigger the fuzes, which leaves you with a bunch of live rounds falling ~40k feet and hitting whatever is below. While self-destructing rounds do exist for the M61 20mm canon, they aren't cleared for aircraft use, only for ground-based use.

well they are air to air missiles and are more designed to hit an airplane with a giant engine (that gives a nice bright ir signature) and <30k ft rather than a cold object at 80k ft. if I had to guess it's probably just a software bug.

It only took a couple box cutters to take down the World Trade Center.

IR and semi active radar guided? As in not really designed to shoot down baloons. The baloon hardly has an IR signature. I'd say it's a pretty good missile if it did the job with 50% failure rate despite being designed for something else.

Baloons and small drones should be downed with lasers. Like cut in half or something like that.

No doubt some bright spark is hard at work on a specialized anti-balloon munition that can do it for at least a little less.

Or they will be if it becomes a real problem anyway.

Because it's designed for a hot, metallic jet at 400knots, at several miles away. How radar reflective is latex or whatever rubber makes up these balloons? How hot is the payload? If you make the heat-seeking missile too willing to lock onto low grade heat sources, it might suddenly decide that a bird is a better target at the wrong time.

For radar guided munitions, the surface you are targeting needs to reflect enough of the radar energy for the seeker head to "see" it.

Also is the AIM-9X really only $400k? That's insane for the capabilities it has.