Solar power sats without colonies...

Structures in space can be vastly lighter than in one gee, but there
are still tidal forces and the stresses of reboosting or
reorienting. At sizes like 600 square meters it's not much of an
issue, but at the sizes needed for SPS there will have to be some
structure.

--- In spacesettlers@yahoogroups.com, bmaillists@i... wrote:
>
> I don't see that weight has to be that much of a problem. Cosmos 1
had a sail
> made of 5 micron thin aluminized reinforced Mylar which covered
600 square
> meters and weighed just 100 kg.
>
> L'Garde (http://lgarde.com) has done quite a bit of work on
Inflatable space
> structures including Antennas and Thermal Power Systems. They
estimate that a
> 700 m diameter antenna would weigh approx 50,000 pounds (22 tonnes)
>
> There isn't much difference between an antenna and a mirror. What
remains is
> just how heavy a brayton cycle engine would be for a mirror that
size.
>
> The other problem is can mirrors of that size be manufactured on
the ground in
> mass production (at say the rate of 1 per day).
>
> Brett
>
> Quoting "Combs, Mike" :
>
> > 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
> >
> > History of space exploration
> >
> > Space exploration
> >
Service.