Ways to sidestep gravity?

Jim Lemmon wrote:

> This is very interesting. I'm not sure I understand
> though.
>
>>>Still, I went to a talk yesterday about laser
>>>
> powered launch
> systems. The guy described a system of using a 100 Mw
> laser
> (cost: around $1 billion, dropping at 30% per year in
> price
> currently) used to point at hydrogen monopropellent
> vehicle
> the vehicle uses a heat exchanger to boil the LH upto
> a
> relatively low temperature 1000C and then chucks it
> out through
> a conventional or aerospike nozzle.<<
>
> Am I correct that each launch throws away a billion
> dollar lasar? It seems like the laser should be made
> part of the returnable craft.

I assume you are joking ;-)

Of course the laser stays on the ground and points at
a launch vehicle from upto a few hundred kilometers
away. The heated hydrogen gets passed out through a
rocket nozzle, not the laser.

> Jim
>

--
- Ian Woollard (ian.woollard@...)

"Is a planetary surface the right place for an expanding
technological civilization?"
- Gerard O'Neill