Bush Cancels trip to Pluto.

[TCO]

Originally posted by KrazyHorse
Why does the geometry of the craft's mirrors have to be non-dynamic?

Oh it doesn't. I just figured it would be easier to have that kind of stuff kept on the ground station where you have people and rigid mounted arrays and micrometers and all that.

[Dauphin]

I think you will find this link topical, even if not wholly related

http://www.newscientist.com/news/news.jsp?id=ns99991603

Artemis is located in a fixed, geostationary orbit 31,000 kilometres above the Earth, while SPOT 4 is travelling at 7000 metres per second at just 832 kilometres altitude. The laser link between the two is just a few metres wide.

[KrazyHorse]

Originally posted by GP
There's another form of loss that occurs becasue of beam spread after hitting the mirrors

Why don't you use slightly concave mirrors that can change focal length?

[TCO]

That's a very interesting link, BC.

[TCO]

Originally posted by KrazyHorse


Why don't you use slightly concave mirrors that can change focal length?

I guess you would. Would be interesting to think about the optics. What radius of curvature?

I think you still get some beam spread from the imperfections in the crystal surface, no?

[KrazyHorse]

Yeah, but right now I really don't know what type of levels we're talking about.

Plus, has anbody else noticed that if you're reflecting those photons 720 times then you've got ~640 times the original beam intensity bouncing off these mirrors? That's a hell of a lot of energy, and any power loss whatsoever is going to be dangerous.

[Dauphin]

plus, has anbody else noticed that if you're reflecting those photons 720 times then you've got ~640 times the original beam intensity bouncing off these mirrors?

You wouldn't have the laser on 24/7.

[KrazyHorse]

No? You'd get more acceleration if you did, though.

[Dauphin]

Rephrase

You wouldn't need to have the laser on 24/7. If you started to have problems with the intensity of the beam you could the laser off.

I heard a suggestion of having a massive parabolic mirror on the craft (say a few hundred metres) and firing several hundred lasers at it. The explosive force on any object at the focal point would provide rapid acceleration to the craft.

[TCO]

Getting back to my baby...I could build that sucker for you. Just need some hard-working grad students, a patch of desert, heavy machine shop (Coors mining has a nice one) and few hundred small nukes and we could do it.

Anybody know some catalogs that have small nukes in them? Can't find them in McMastercar.

[KrazyHorse]

Next time you're on a sub maybe you could swipe some.

[Dauphin]

I just read something interesting from the JET propulsion labs in Pasadena.

At present technology we could send a 10kg satellite to Mars within ten days using lasers and solar sails. That shocked even me.

Also there was a comment on inter-stellar travel....

A phased laser array we have designed to send a probe in 40 years to the nearby star Alpha Centauri would be 1,000 kilometers (621 miles) in diameter.

[KrazyHorse]

Originally posted by Big Crunch
I just read something interesting from the JET propulsion labs in Pasadena

JPL iz 733t

[Dauphin]

Originally posted by KrazyHorse


JPL iz 733t

You lost me.

[KrazyHorse]

Never mind...