Solar power sats without colonies...

Storing the heat is not expensive. In the steam-turbine approach
it's a tank of molten salt; in the convection-tower approach it
literally costs nothing because it's the ground underneath. It
would be expensive for SPS because of all the mass it needs, but not
here where the ground is already underfoot anyway.

I want to see space developed, but launching the collection system
and the maintenance personnel and everything the maintenance
personnel need and the transmitter, plus paying for the rectenna on
the ground, just sounds a whole lot more expensive than painting,
roofing, and paving with PV instead of conventional paint, roof
tiles, and pavement, or choosing systems for low cost at the expense
of reliability (which you can do if the maintenance people are on-
site already, but not if they're $500+/kg away).

If it were launching just the collection systems, the factor of
about four (dark half the time, half-dark the other half) well might
cover it.

--- In spacesettlers@yahoogroups.com, bmaillists@i... wrote:
>
> Whether groundbased Solar is Thermal or PV or both, it still has
the problem of
> generating and storing (the expensive bit - even if you use
thermal methods)
> enough electricity for 24 hours off of approximately 5 peak hours
of sunlight.
>
> Brett
>
> Quoting Dan Wylie-Sears :
>
> > Indeed SPS can be thermal. But my point in mentioning thermal
was
> >
> > that it addresses day/night concerns about ground-based solar,
and
> >
> > of course SPS don't have that issue to begin with.
> >
> > --- In spacesettlers@yahoogroups.com, "Combs, Mike"

> >
> > wrote:
> >
> > > From: spacesettlers@yahoogroups.com
> >
> > > [mailto:spacesettlers@yahoogroups.com] On Behalf Of b
> >
> > > > SSPS can be solar thermal. Thin film metal mirror focused
> >
> > > > on a Brayton or Stirling Cycle engine.
> >
> > > And in fact, O'Neill once made the point that the reason why
solar
> >
> > > thermal gets excluded from so many SPS studies is because of
the
> >
> > greater
> >
> > > weight. But if making SPS from space materials, weight
becomes a
> >
> > lesser
> >
> > > consideration.
> >
> > > Thermal would certainly beat PV for efficiency. I worry about
> >
> > > maintenance, though.
> >
> > > Regards,
> >
> > > Mike Combs
> >
> > Science education
> >
> > Space exploration
> >
Service.