BalloonsInVLEO

There are atomic oxygen issues for VLEO sats, the front of the satellite slowly corrodes away from the impacts. They're longer lived than current balloons but mission lifetimes more than low single digit years aren't really feasible right now.

Right now they fly for months, but years is possible with the right design.

The can sometimes leak slightly but they make up for it by dispensing small amounts of ballast material.

All the companies I know of are US based. That said if you know what you're doing it's much lower risk than a satellite venture

I've seen various balloons more or less constantly spook the UFO people. There are a few designs that don't look like a traditional balloon so everyone thinks they're some sort of cloaking field or something

That info would strangely enough dox me/be a trade secret but there are companies doing both exempt and non exempt, and both have GSD better than any commercial satellite

We already have fully autonomous space drone swarms armed with nuclear warheads, we just keep them underground/underwater because...humans are weird.

Yup, I've worked on both and the balloons are generally just better platforms given current constraints. They can actually be steered rather accurately, if you're ever bored go look at the ADSB logs of the Aerostar balloons, they regularly can be found wandering the country and if you look at the altitude history you can start to see how they work.

They're generally more environmentally friendly too, worst case you have to go ask a farmer to retrieve the thing out of their field.

Nope!

Weirdly, I'm probably the one person who's worked extensively with both paradigms...

There are several players in the balloon market spinning up. It's becoming very hot very fast.

The balloons in question are much smarter that radiosondes now. They are fully capable of autonomous navigation within certain limits and can even orbit a point for days at a time via some clever weather mechanics. They're also very easy to launch. Two guys and a truck can launch over a dozen in a day and they're all aggregated and flown remotely via various links.

On the payload side it's actually much easier to do optics on a balloon, you have all the same pressure and thermal issues as space but you can iterate much faster when your cost to first pixels is thousands instead of tens of millions for the same ground resolution (GSD, drives necessary aperture size). I'm not going to spell out the details on either because that's the secret sauce that pays my mortgage but it suffices to say, if you're 10x lower, you need a lens that weights a little less. It's also worth noting that a VLEO sat will only be overhead for a few minutes, balloons can stream live video as long as you want, right now (no future tech or constellations needed).

The class of UAV that can begin to compete with a balloon is two to three orders of magnitude more expensive and still has nowhere near the endurance.

There are also other sensors and phenomenologies that are wildly more capable on a balloon platform than any type of satellite or UAV but I'll get yelled at if I spell any of those out...