The ISS power system as real-world baseline (was Hitssquad is a troll.)

--- In spacesettlers 11009, ANTIcarrot wrote:
> *Though I'm sure its over engineered, I question whether
> the solar panels on the ISS really weighs 100tons by themselves.

Did you click the link? Here it is again:
http://en.wikipedia.org/wiki/ISS_Solar_Arrays#Truss_and_solar_array_as
sembly_sequence
http://tinyurl.com/6exgqf

Element Mass (kg)

Z1 truss 8,755
P6 truss solar array 15,824
S0 truss 13,971
S1 truss 14,124
P1 truss 14,003
P3/P4 truss solar array 15,824
P5 truss - spacer 1,864
S3/S4 truss solar array 15,824
S5 truss - spacer 1,818

Total: 102,007

A final 15,824 kg S6 truss - solar array is scheduled to be installed
in February 2009. This would bring up the total mass to 117,831 kg.

> *I'm almost certain they don't represent half the total
> cost of the station's accumulated lifetime budget

OK. How much of the ISS's cost does the ISS solar power system
represent? What makes you think it cost substantially less than $50
billion?

> *Scaling linearly (even if true) from these two 'facts' would
> be beyond any reasonable boundry of accidental foolishness.

No one has said or suggested that the ISS solar power system would
have to scale up linearly. Normally, things that are scaled up
benefit from economy of scale. I assume that that would be the case
with regard to space-based solar power systems as well. In ssi_list
message 8084, you said:

> > If we assume a launch cost of $1,000/kg to GEO, such a
> > solar power system scaled linearly would cost $1
> > million/kW = $1 billion/MW = $1 trillion/GW, just to launch.
> But no one will take you seriously when you start claiming
> that the ISS is some kind of irrifutable proof that we cannot
> do better.

I did not say that the ISS represents proof that we can't do better.
I point to the example of the ISS because it represents -- by far --
the largest orbiting solar power system fielded to date, and because
it is recent. The fact that it includes a lot of trusswork is
interesting, because large collector arrays -- especially ones that
are as large as 10km by 10km, as you have previously described, and
which I assume would be the approximate size of a 10GW array (some
132GW of solar power impingement * cell efficiency * arial efficiency
(a group of cells or lenses or reflectors does not cover an entire
panel, and the same goes for groups of panels in relation to arrays,
and array subsections in relation to entire site areas) * wire
losses, dioded losses, etc. -- as others have said, "The cell
efficiency is not the site area efficiency! ... Springerville
facility gives us some interesting real world numbers for comparison.
Its areal efficiency is something around two percent, owing to the
above factors." http://www.tinaja.com/whtnu07a.asp) -- might be
expected to include a lot of trusswork.

As you yourself recently said:

"Paper rockets can't put anything into orbit. ... I'm sure sea-dragon
would work, but I'd be concerned by unforseen operational problems
that might plague such a vehicle."

If your proposed solar power system is
cheaper/lighter/better/different than that of the real-world example
of the ISS -- one that has had to deal with real-world operational
problems, both foreseen and unforeseen -- please tell us how it is
so? You seem to give a price (clarification was requested, but so far
none has been given) that is not merely cheaper, but nearly a million-
fold so. Does your proposed system use any trusswork at all? How much
does that trusswork weigh per unit of power output? Have you
considered how beefy the trusswork on a kilometers-long-and-wide
array is going to have to be to overcome just the uneven twice-daily
(twice tugged clockwise alternating with twice tugging
counterclockwise -- looking down from polar north, we would see the
array turn clockwise between midnight and 6am, counterclockwise
between 6am and noon, clockwise between noon and 6pm, and
counterclockwise between 6pm and midnight) back-and-forth
gravitational tugging by the Earth as the array tries to maintain
flat (perpendicular) orientation with the sun? If those trusses (if
there indeed any involved) are not strong enough, that array might
shatter from the pendulum-like flapping. This flapping from
gravitational-tugging is tidal and is what caused the moon to
rotationally lock to the earth. Has it been considered that systems
are going to have to be in place, and operating, to overcome these
tidal forces -- at least to the degree that the tidal-forces don't
cause the arrays to rotationally-lock to the earth? Does it employ
typical space-grade PV panels? Does it employ concentrators? Your
ssi_list message 8058 (in respect to the Ben Bova SPS proposal) seems
to imply that it does not employ concentrators: