Re: Solar concentration mirrors in the outer solar system

From: dave schneider (d_schneider_at_emulex.com)
Date: 06/30/04 

Date: 30 Jun 2004 16:20:58 -0700

Bernard Peek <bap@shrdlu.com> wrote:
> In message <cjameshuff-C7F5FD.11543027062004@news02.east.earthlink.net>,
> Christopher James Huff <cjameshuff@earthlink.net> writes
> >In article <veDcqDHv4Z1AFwGB@shrdlu.com>, Bernard Peek <bap@shrdlu.com>
> >wrote:
> >
> >> (The spherical shape isn't ideal, I think spinning the bubble could
> >> create something closer to a parabola.
> >
> >Spinning the bubble and using uneven heating could produce something
> >very close. Perhaps you could start out with a hollow cylinder, "doped"
> >with varying amounts of pigment along its length to influence absorption
> >of solar heat. Spin the cylinder up and put it in an existing solar
> >furnace.
> >
> >More likely, use gas jets and more controlled heating to shape it the
> >way you want. A relatively small reflection concentrator moving along
> >the spinning mirror, adjusting the heating to make sure it expands
> >evenly into a parabolic shape.
> >
> >For the first generation mirrors, I'd just look at using something like
> >*** mylar stretched over rigid frames, approximating the parabola with
> >flat sections.
>
> For the first generation a hemispheric reflector might be good enough. I
> was thinking of a bootstrap process, where each furnace would be used to
> build progressively larger furnaces.
>

I brought up the "blow a bubble, make a mirror" idea a few months back
(sst, IIRC, but maybe I'll take the time to look it up).

The responses indicated that for the size mirror needed for any useful
purpose, blowing a bubble was impractical, would still require a
framework for stability, and making flat sections was a much more
practical idea. In addition, at the spherical radius of the mirror,
it would be very hard to distinguish between the curved and the flat
sections; it would be big enough that, like the parking lot outside
mission control, the sphere would locally measure as flat.

Perhaps you could make flat section in situ by spinning the melt like
pizza dough, so don't put away that axle and driveshaft yet.

/dps

Loading