High altitude balloons, air tanks, & radar

[the_norseman]

Basically the story is set in a world with roughly present day technology. There is an airbase located on an island not too far away from the coast, while the coast itself is mostly unclaimed for various reasons. My group wants to have a look at this airbase, but getting past the radars would be difficult. They could send airplanes, but they'd

Comments

[sandwichwarrior]

1:
The issues when determing a radar cross section isn't metalic composition it is the Surface area, density, and conductivity of the contact vs. the Frequency and PRF/PRI of the radar. As a result the balloon is going to show up on radar.

That said, if your badguys are looking at small bright contact at low altitude (helicpoters maybe?), a big fuzzy one drifting on the wind at 80K might get completely ignored. (especially if it doesn't have much of a IR or ES signature)

2:
I don't know

3:
Very good, trust me.

[the_norseman]

I imagine they'd be looking for something like spyplanes. It's a relatively new base though, so I doubt they'd have time to install giant monster radar sets, but there could be naval ships nearby and AEWs. It is an airbase after all.

Another worry is that they'd be able to track the balloon, and try to hit it when it comes down, that is before it's picked up.

Basically I think this balloon idea is neat, but I don't want to portray the defenders as morons.

[scribefigaro]

My understanding is that the bulk of the envelope of a balloon, being a synthetic material as well as very thin, is going to have very low attenuation over most radio frequencies and wouldn't be seen in at least civilian surveillance radar. (Unless, for example, there is a lot of condensation on its surface.) It's whatever the balloon is carrying that has enough density to be detected and identified by an ATCS as a LTA vehicle.

Sort of like Wonder Woman's invisible jet - doesn't matter if most of the vehicle is invisible, because its pilot and payload are not.

[sandwichwarrior]

That said... Its signature might differ enough from a regular Spyplane/UAV's that the defenders might just miss/ignore it.

Especially if the balloon has a minimal Infrared/Electro-magnetic cross section, and you throw in a diversion.

[revchris]

As far as the air tanks go, you can get fiberglass scuba tanks. I don't know if they have no metal in them, as I'd think you'd need a little for fittings and the regulator, but you can probably get rid of a lot of it that way.

[duckodeath]

At that height, the people on the balloon couldn't see the most interesting spots (since even 80,000 feet is the edge of space), so is would they really need to be on board for that reason? Why wouldn't they use a video feed and have ground controllers aiming the cameras the way they do for unmanned drones?

The question immediately made me think of this http://en.wikipedia.org/wiki/Project_Excelsior.

[the_norseman]

Because the opposition would detect an operating radio transceiver.

[duckodeath]

How about this though -- manned or unmanned, the balloon is depending on the wind to get to position and then to get away. Is there enough wind at the altitudes you're proposing to move the balloon? From what I can tell, the high-altitude stuff is generally in a fixed position (i.e. straight-up) and from what I've read air movement diminishes greatly once you are above the jet stream to the point where the balloon might not go anywhere once it was at the height you need.