Cost not an issue???

Cost not an issue???
How can anyone say that the initial cost of reaching space is not an
issue?
Almost all the postings here are concentrating on what we do once we
get to space, with no concern about the cost, in pollution and the
depletion of Earth's resources to get there. IMHO the money is
important but entirely secondary to the human cost to those left
behind. Sure, we may be able to automate and develop some space
resources but we aren't going to go far without people. By
existing
launch methods only a handful of the chosen will get to space and
only at extreme cost to those of us left behind. Is this the cost of
the progress and advancement of human kind?

At the end of his response to my posting Fred says

"I think with improved materials science and volunteer
efforts, reduced launch costs by a factor of ten will happen almost
inevitably down the road. And even if not, an automated space based
infrastructure could send laser launch vehicles down to earth and beam
energy for then to use to launch people at no cost -- a good use of
SPSS
in my opinion. But once again this goes to show how the bootstrapping
approach differs from the Earth infrastrucutre approach."

1. Detailed research (see
http://www.puaf.umd.edu/faculty/papers/fetter/2004-P&S-SSP.pdf)
repeatedly `proves' that, even if we accept that `going
solar is
inevitable' SPSs cannot compete because the high basic cost of
space
launches, arguing, not unreasonably, that the extreme cost cannot be
balanced by the greater availability of sunlight. The target given is
that launch costs must be reduced by a factor of 20x-50x for SPSs to
be worth even considering (the lower estimate is for a higher % of
space supply, allowing for the alternate, additional cost of ground
storage). Your suggested `factor of ten' just doesn't
make the cut.
2. However, you then go on to say "automated space based
infrastructure could send laser launch vehicles down to earth and
beam energy and then to use (the beams) to launch people at no cost --
a good use of SPSS in my opinion." This is exactly my
point
but your approach is to put the cart before the horse, developing
SSPs and then using them it to provide cheap launches and then
develop the technology to launch people at `no cost' (? I
assume you
mean no cost in additional energy or fuel?) The launch technology
must still be developed. Although I question the use of lasers, if we
first develop the launch technology you refer to, then surely the
cost of establishing the whole system can be at `no cost'.

My arguments are not entirely without basis. I am trying to get
people to follow a trail of evidence to what I know is a complete and
proven solution to these problems. To do this, it is necessary to
extend the logic and the predictable `ideal' course of the
development of this technology.
[As a significant aside, I believe it is generally accepted that SPSs
would use masers to send energy to the ground where it would be
collected over an area of 5km-6km (total dia). Energy levels across
the collector would vary from perhaps 1kW/m2 at the edge to 10kW/m2
at the centre.]
If you accept this, that SPSs can provide useful energy to the
ground, the next stage is to consider precisely how that energy can
most efficiently be directed to a launch vehicle.

Maser (ie microwaves) can be collected and redirected in three ways.
1. At low densities, a rectenna aerial array is most effective.
2. Metallic mirrors can reflect the energy directly into a
focus, ie at the top of a Power Tower or beneath a craft or
3. Waveguides. From such a focal point(s), energy could be
delivered through a waveguide channel to a remote point of use.

Each alternative obviously has limitations. Let's consider them:
1. The rectenna introduces an energy transponder (with the
associated losses) but is a cheap and highly effective way of
producing convenient and versatile electricity for transmission by
(costly) power lines
2. Mirrors. A single reflection to an end point use is obviously
the most efficient and effective way to use the energy. Additional
reflections are entirely possible (even back into space) but
introduce greater losses. It is obviously best to reflect energy at
the highest E/D (energy/density) possible and by the most direct
method available. Agreed? Think about it. If you were to supply a
launch vehicle in this way, how much energy could you collect at the
ground by direct reflection from an SPS supply? How would you go
about it? What are the limiting factors? and, Where would that launch
vehicle be placed?
3. Waveguides. From a group of (smaller) collector areas, or if
collecting high E/D energy from a vast collector area, a microwave
guide channel system could collect the m/waves and deliver them to an
end user some (limited) distance away. This could be of advantage if
sharing the energy among a variety of end users (ie a number of
launchers). Because of beam E/D considerations, the waveguide tunnel
must be of significant dimensions and must of course be insulated
from m/wave leakage. (Ie it must be insulated by metal or some
effective m/wave insulating material like mica). The channel will
also need a means of controlling the delivery of the m/waves to
specific destinations ie a switching system of gates and/or sluices
4. Ground-based Transducers. If an SPS can convert solar energy
in space to beam m/waves to the ground, it is also evident that the
same transducers could be placed on the ground but could only collect
1/5th the energy (because of day/night, cloud and other limitations).
There could be also be very significant advantages in
combining `daytime' and `24hr' systems.

If you follow me this far, consider what the whole energy collection
and (launch) delivery system at the ground would look like and let me
know what conclusions you reach. If you can't be bothered to
think it
through, next time I'll post a clue.
CCMc