Re: Lightcraft & launch costs

Michael M. Butler (
Fri, 14 Aug 1998 10:50:04 -0700

I've always loved the idea of laser launch.

The rule of thumb for the flight plan, BTW, used to be "thirty gees for thirty seconds", so it's a bit of a hard ride. IIRC, that's something like 8-10 gees more than the *peak* gee load you get with modified military launchers. Users had better think about that carefully.

The economics are complex, and (aren't they always?) fraught with politics. Here's what I think:

The incremental cost per pound has every reason to be very low indeed. I refuse to believe the lowest figures I've heard, but $100 per pound seems possible, provided you amortize over a lot of launches, and there are no surprise failures on the lasers, etc.

The frontend costs are significant (the laser array and the power source for it: I seem to recall old work suggesting a dedicated nuclear power reactor?).

Expect some "resistance environmental"--the engine employs air-detonation, which means NOx byproducts. If I remember right, the last little bit of delta-vee takes boiling something off or out of the airframe, and that means changing the beam so it focuses on the airframe somehow, but neither loses track nor hits the wrong thing nor cooks your payload, all at maximum distance through (mirage shimmering) air at maximum beam depression.

The use of the ground station technology for other purposes such as ballistic missile point defense should not be overlooked. Expect this to be controversial in some circles.

Lastly, there are the usual caveats about government programs, bleeding edge tech and technologists selling sweet dreams at low prices that never show up.


At 10:52 8/14/98 -0400, you wrote:
>I saw this on tv last night:
>They claim it will reduce launch costs for small satellites
>by "several orders of magnitude" within something like 5
>But I can't find any exact figures. Does anyone have an idea
>of about how many dollars/pound (or kg) we are talking about
>here, and will this thing really make it possible for the
>average joe (or company) to have their own satellites?
>The future has arrived; it's just not evenly distributed.
> -William Gibson
>Visit Hypermart at for free business hosting!

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