Scientists develop mini Death Star to protect us from asteroids

The Telegraph ^ | March 3, 2016 | Rob Crilly

[Elsie]

Where's that assteroid again?

[Rebel_Ace]

"...Over a period of time, the asteroid is deflected from its original course..."

"...Only if the thing is not rotating..."

Actually, yes, even if the thing is rotating, although that makes the energy requirements of the laser go up somewhat, but not much.

The laser heats a spot where you want the "jet" to occur, and with enough laser power, that happens in just a few seconds. As the asteroid rotates beneath the laser beam, other areas of the rock are vaporized, but the direction of the impulse remains the same. It would just create a linear scar on the asteroid, instead of a simple "hole" of ejected material. The key is that the craft delivering the laser is at "station keeping".

You can even use the laser to first stop the asteroid's tumbling, if desired.
Here is a link to a video testing a laser on a small rotating rock, to illustrate the principle: Small Scale Test of Laser Ablation

[Hot Tabasco]

Yea, right......Asteroids today, planets tomorrow. That’s how intergalactic wars get started.........

[McGruff]

They envisage putting an unmanned De-Star craft in orbit.

De-Star...De-Star.

[Elsie]

Ablation.

THAT’s the word I was thinking of.

[Elsie]

The laser heats a spot where you want the "jet" to occur...

And the ideal spot would be 90° away from the direction it is heading towards us.

The problem; as I see it; is that the laser would be quite near Earth and the jet would be mainly on the lead surface.

Slowing it down, but not deflecting it away.

[Elsie]

Let’s do a lab experiment.

Hang a rock on a pedulum in a vacuum.

Pulse that sucker with the largest cutting laser we have now.

Measure the deflection.

Scale up.

[Elsie]

Yup.

Miss the asteroid and the light goes on FOREVER!

If it hits near Marvin; he’ll be, shall we say; PISSED!

[Rebel_Ace]

And the ideal spot would be 90° away from the direction it is heading towards us.

The problem; as I see it; is that the laser would be quite near Earth and the jet would be mainly on the lead surface.

The laser is on a spacecraft sent TO the asteroid. The spacecraft holds a “station keeping” position near the asteroid, and wails away on it with its laser. The jet would directed in whatever vector that would optimize deflection.

[Elsie]

Seems like whatever power source was on the spacecraft with the laser could be more efficiently used if it were merely a booster to push the rock as needed.