[ExI] Why no space colonies or lunar bases? was Mooon.

[Samantha Atkins]

On 07/22/2011 02:39 PM, Keith Henson wrote:
> On Wed, Jul 20, 2011 at 4:24 PM,  Damien Broderick<thespike at satx.rr.com>  wrote:
>
>> And here we are on the 42nd anniversary of the first Moon landing. Two
>> generations later, just about. No Luna City. Not even a Luna Hovel. Sigh.
> Freeman Dyson explained why in 1979.  I talked him (and the
> publishers) into letting the L5 News print a chapter from _Disturbing
> the Universe._  You can read it here:
>
> http://www.nss.org/settlement/L5news/L5news/L5news7908.pdf
>
> The bottom line is that transport into space is 10,000 times too
> expensive for space to be colonized.
>
> That's largely due to the small payload fraction, which in turn is a
> direct consequence of an exhaust velocity which is half the delta V
> needed to reach earth orbit.
>
> Chemical fuels just won't do it.
>

So why not bring up Orion and its relative clean variants for putting 
large payloads in GEO or on the moon?  At the very least space tugs with 
fission power plants and space platforms with reasonable sized fission 
plant and fission plants on the moon seem obvious.

> But in recent years other ways have opened up, relatively low cost,
> high efficiency, solid state laser diodes and low cost microwave
> generators.  It's not entirely clear how to best exploit such beamed
> energy sources, but they both offer exhaust velocity up in the same
> range as the 9 km/s needed to get into orbit.
>

These can't do the trick of lifting from LEO to GEO or into lunar 
insertion efficiently today.

> It's still too expensive for self funded space colonies, but if this
> works out, it will only be 2 orders of magnitude too expensive rather
> than 4.

Go with space nukes and you can conceivably do this today.

- samantha