William Happer

And so that was a problem that was well known to astronomers.

But the inverse problem, a star does the same thing.

When you focus it on a photographic plate, you don't get a point.

You get lots of speckles.

And so astronomers knew how to solve that.

You know, the problem is the incoming wave gets wrinkled by the atmosphere.

They're little warm patches and cool patches.

And so what you can do is you reflect the incoming star light from an anti-wrinkled mirror.

So it comes in wrinkled, it bounces, it's nice and flat, then it focuses and you get a point.

And you can do the same thing when you're trying to shoot an incoming missile.

You pre-wrinkle the beam so that when it reaches the missile, it actually focuses all the power onto the missile.

So it's called adaptive optics.

And the mirror is called a rubber mirror.

It's a mirror that you can adjust.

But to do that, you need to know how to adjust the mirror.

So you have to have some information to how do I wrinkle it, push here, pull there, etc.

And the way the astronomers did it was they used a very bright star in the sky.

And then for nearby stars, you could use the bright star to correct your mirror for all the neighboring stars.

But it only worked for a degree or two off the direction of the correcting stars.

And so unless the Russians attacked us during the night from the direction of the brightest stars in the skies, we couldn't do anything with our lasers.