A proposed solution to the problem of space flight

>
> > >So laser ablation propulsion looks like the weak link of the chain to
> > >me, and if that's right, it would make sense to push for demonstrations
> > >and validation of that step, to move it as quickly as possible from
> > >theory to practice.
> >
> > Right. Which is why the proposal to build a 1/1000th scale test
> > laser (4-5 MW output) on a crash basis. If it works, and there is
> > every reason to expect it will, not only would it demonstrate laser
> > ablation propulsion, but it could be used to full time to de orbit at
> > least 500 tons of space junk per year. (Or put the junk in compact
> > lumps for later reuse as materials or shielding mass.)
>
>That's a very intriguing application. It would require government
>funding, though, as I don't see how there's any other obvious customer
>for clearing space junk.

The insurance companies who insure satellites should be
interested. They probably would not pay for it, but they probably
would put pressure on governments.

Point being, space is worth some number of billions per year. That
use will be degraded by some number per year by space junk. What is
it worth to space industry to clean out the space junk? If enough,
then the users should be willing to pay some number less than the
anticipated cost. That is a secondary value to the main one of
testing the big propulsion laser. (The big laser could clean out all
the junk in a months.) The military might well find it in their
interest to shell out a billion, especially if they got a huge dual
purpose laser out of the deal.

>It might be a tough sell even then. Still
>worth pursuing though.
>
> > There are a lot of engineering details that need to be solved, but
> > the fundamental ones like pointing accuracy have long been
> > demonstrated by telescopes.
>
>Right.
>
>How small a launcher could you make with this system? Say you only
>wanted to launch 10-kg microsats?

The number from Jordin Kare is 1 MW/kg. So 10 kg would take 10
MW. The cost per watt is about $10 so a laser of this size (assuming
RDTE were already paid for) would be about a $100 million. It would
put up 10 kg sats at 10-20 per hour.

Keith