[buckalfa]

Just for the sake of conjecture, let us say a radar system is based in outer space, not the atmosphere, land, or sea Would this potentially render aircraft stealth techniques obsolete?

[SampleMan]

Just for the sake of conjecture, let us say a radar system is based in outer space, not the atmosphere, land, or sea Would this potentially render aircraft stealth techniques obsolete?

Not really.

The "hole return theory" would require unbelieavable power (for area coverage) and pencil beam radar, smaller (from 150 miles up) than the aircract width itself.

Additionally, radio beams difuse, just like waves on the surface of water, so holes close up after a fairly short distance. i.e. if you form a ripple on the surface of water and block its propagation with your finger in one spot, the edges of the ripple will come back together as it expands.