..Citizens for Space Based Solar Power....Letter to Obama

On Aug 6, 12:14*am, Hugh Gibbons
wrote:
In article ,
*"Wayne H. Wilhelm" wrote:





Assuming you beam the power back to Earth as microwaves (necessary for
efficient conversion from RF to DC), you need about a 1 km diameter
transmitter antenna to focus on an area on Earth of about 10km diameter
and capture 90% of the downlink energy. *That's assuming you use 2.45GHz
downlink frequency. *A *photovoltaic array that big on Earth captures
average power of easily 13GW peak power. *That translates to average
usable power of about 4 GW. *So a solar power satellite that provides
less than 4 GW DC power out on Earth is therefore impractical as
compared to photovoltaics on the ground.

Current launch costs run $5000 per kilogram to geo. *If you cut that by
a factor of 10 with some new exotic technology, you'd still be looking
at a launch cost in the hundreds of $billions for an efficient system..
That's in addition to the costs of the materials, which would be much
more than the cost of materials needed to build a solar collector array
on *Earth, and it doesn't count the extra cost of building the array in
space or maintaining it there, *but those costs would also be huge.

The guys planning this stuff are 100% about finding cool things to do in
space and 0% about caring whether this is an efficient way to provide
energy.

As technology goes, in the 1950's or 1960's, we first saw a tv character
with a wrist watch on which he could call and talk to people plus view them
on a miniature tv screen, all fitting on his writs. *Everyone knew that
while this was cool to make believe about, it could never happen in real
life. It just wasn't scientifically possible. *40 years later, it's a
reality.

You don't get the difference between surmountable technical barriers and
laws of physics. *It will ALWAYS be cheaper to build power stations on
Earth.


What physical law of the universe says that? hmm?

Its certainly not energy.

It takes as much energy to place something into orbit as it takes to
carry something by air around the world.

Orbital velocity is 7 km/sec - that means a metric ton of material on
orbit contains

E = 1/2 * 1,000 * 7,000 * 7,000 = 24.5 GJ

That's about the energy content of a ton of coal, or 200 gallons of
gasoline., So, this costs between $70 and $800 depending on what sort
of fuel you use. Of course, if you use laser or maser energy beamed
from space cheaply in the first place, the costs could be
substantially less! In fact getting the energy costs to about 1% of
what they are today by beaming energy to users on the ground - lets us
contemplate universal access to space - as cheaply as say driving
cross country or across town.

For comparison lets look at a Boeing 757. It travels 6,267 km on
43,400 liters of jet fuel. That's' 1,375 GJ per fill up. The Earth
is 40,000 km in circumference - so, that's 6.38 refuelings to travel
around the world - a total of 8,776 GJ. The payload of a 757 is
about 30 tons - so that's 292 GJ per ton carried around the world.
Over 10X the energy of an orbiting payload.

So, if we can carry generator parts in the cargo holds of aircraft at
a profit, what is the physical principle that stops us from shipping
parts by rocket to orbit?

Obviously there is none.


Even if we have to build a 1km diameter transmittin antenna, that's only
1,000 meters, hardly an insurmountable goal, especially in space. *

Calculate the mass and multiply by the cost of shipping that mass to geo.
The solar collector is 10x the size of the antenna, and probably over
10x the mass. *

Did you do the calculation? Lets imagine a large concentrator made
of thin reflective film inflated in space

http://www.coolearthsolar.com/technology

A sheet of mylar bonded to a sheet of clear PET - stabilized by a ring
of some sort - an inflatable one. You have about 20 micron thick
layers - so a square kilometer totals about 20 cubic meters - which
mass about 25 metric tons per sheet - say 50 metric tons altogether.
Another 10 tons for the solar pumped laser target and laser guidance
beam.

Can you make an inflatable satellite? well duh!

http://en.wikipedia.org/wiki/Echo_satellite

We did that way back in 1959 !! A 41 meter diameter satellite massed
56 kg - and 40 kg of that was the tank to inflate it!! 5281 sq m-
massing less than 16 kg.- 330,000 sq m per metric ton. That's way
less than my estimate above.

Lets say it costs about $10 million per ton to launch on a conventioal
rocket - that's $600 million per launch. With a fully reusable
system, that is flown 500x to 1000x before complete rebuild - that's
$30 million per launch.

Construction costs around $1 million per ton - so that's another $60
million -

so,withi ELVs costs are $660 million with RLVs assuming you do it more
than once - costs are $90 million - that's your launch costs.

Solar pumped lasers - which use multiple bandgap PVs driving free
electron laser setups that can be quite efficient - beaming energy to
bandgap matched PV units on the ground in the IR - window near 1,100
nm - find about 30% of the incident energy on the satellite appears on
your loads on the ground.

In fact I've done studies with lasers that show you can beam IR energy
at 400 watts per sq meter at 1,100 nm wavelength - on silicon PV
systems - and get 380 watts per sq meter out of the PV system. You do
have some small losses to atmospheric dispersion and the big loss is
in the PV/laser setup on orbit. There you have a six junction
Germanium substrate mulit-spectral cell - driving a free electron
laser ...

So overall efficiency is 30% from space to ground.

High efficiency solar cells
http://www.boeing.com/ids/news/2006/q4/061206b_nr.html

High efficiency electron lasers
http://www.elsevier.com/wps/find/boo...on#description

High efficiency absoprtion of matched laser energy
http://oai.dtic.mil/oai/oai?verb=get...er= AD0721888

Now, with in space you have 1,366 watts per square meter

http://en.wikipedia.org/wiki/Solar_radiation

that means that for each square meter in space you have 409.8 watts
per sq meter on the ground. Now beaming IR energy at this power level
is about the same amount of power that's beamed by the sun - at a
wavelength that doesn't get scattered or absorbed by the air - 1,100
nm - it really isn't a problem. You also size your receiver to match
your satelite area.

This means that your satellite which costs between $660 million and
$90 million per sq km to put up produces a net 409.8 million watts per
sq km. That's a cost of about $1.50 per watt - for the first one -
and $0.27 per peakwatt if you do it many times.

Each watt on space - produces 8.7 kWh of energy per year. Say the
satellite has a 5 year life span. That's between $0.30 to $0.05 per
year - and with 8.7 kWh - the satellite's life cycle cost is between
0.6 and 3.6 cents per kWh

LESS THAN THE COST OF COAL IN A COAL FIRED GENERATOR.

If the life time is greater than five years - costs of the satellite
are even less.

If the cost of the 'ground station' is less than $1 per watt - we have
a satellite system built at LESS cost than a coal fired generator.

Now, I have solar cells, that cost $0.07 per peak watt

http://www.usoal.com

These generate about 1.3 to 1.7 kWh per year per installed peak watt.
With a bandgap matched laser power satellite iluminating a ground
based array, they produce an additional 8.7 kWh - adding to the sun's
contribution - yeilding 10 to 10.4 kWh per peak watt of installed
ground based system.

Obviously, once large tracts of ground based solar panel arrays are
installed, it makes sense to use bandgap matched solar pumped laser
satellites to increase their usefulness.

In fact, my plan is to build large arrays of solar panels near coal
fields and generate hydrogen from water and sunlight. Then use the
hydrogen to hydrogenate the coal making gasoline diesel fuel and jet
fuel, along with extra hydrogen which is piped to coal fired plants
along the same rail line rights of way that coal is now shipped.

Then,as I get more profits from the sale of hydrogen and fuel, I build
big rockets to orbit power satellites to multiply the output of
hydorgen, liquify the excess, and create a hydrogen fuel
infrastructure that exceeds the present fossil fuel infrastructure.

Eventually, with advances in laser technology, energy is beamed
directly to consumers and transmitted in cites in optical fibers
creating an all optical power grid to replace electriicty and fuels.

At that point,MEMs based laser powered rocket arrays - forming
propulsive skins around aricraft - provide safe reliable quiet long
range personal ballistic transport and even - personal space travel at
costs that are less than driving across town by automobile or bus
today.

These are all grouned in physical reality - and working through the
numbers - obviously there is no fundamental barrier to creating
practical space power systems to meet all our energy needs now and
into the future.

http://sciencelinks.jp/j-east/articl...06A0418442.php
http://www.springerlink.com/content/9nu7ev28ybp73a3a/
http://www.space.com/businesstechnol..._001103-1.html
Cost 1
Trillion? *If government controls and regulates it, quite likely.
Alternatives? *

The alternative is to build solar power stations on Earth that are a
hundred times cheaper to build and cheaper to maintain.

Where do you get that number? I've just shown you that with
appropriate choice of design elements, we can capture and beam a watt
worth of power on the ground for less than $1.50 - and because capital
utilization is nearly 100% in space - while its less than 20% on the
ground - we actually make terrestrial solar power less expensive by
adding power satellites - once large arrays are built.

We can achieve miracles if we're only imaginative enough to
figure them out.

We should focus on the ones that are WORTH figuring out.

Yes, and carefully analyze things before making bold statements that
turn out to be bogus.

*This isn't one
of them.-


Why? You have given no references, no analysis - you just quote
numbers out of your ass - without anything to back them up. Your gut
tells you that things are 100x more expensive so you shout down
someone who doesn't see it that way - without one shred of evidence.
Do you really trust your gut that much? lol.

In article
,
wrote:

Orbital velocity is 7 km/sec - that means a metric ton of material on
orbit contains

E = 1/2 * 1,000 * 7,000 * 7,000 = 24.5 GJ

That's the wrong energy. We're not talking about orbiting power
satellites at 1700 kilometers altitude. We were talking about geo. At
geo, the kinetic energy is only 4.7 GJ/tonne. That doesn't mean it's
cheaper to get things to geo than LEO. You also have to lift the mass
to the orbital altitude. To get to orbit at all, you must deliver
energy of 32 GJ/tonne, and that's way too low to be practical (200 km).
To get to the altitude you were describing, where orbital velocity is
7km/sec, it's 37.5 GJ/tonne and at geo it's 57.3 GJ/tonne.

That's about the energy content of a ton of coal, or 200 gallons of
gasoline., So, this costs between $70 and $800 depending on what sort
of fuel you use.

No it doesn't, because space propulsion is not that energy efficient.
The fuel that must be used to accelerate a mass to these velocities is
many times what your assumptions say.

Of course, if you use laser or maser energy beamed
from space cheaply in the first place, the costs could be
substantially less! In fact getting the energy costs to about 1% of
what they are today by beaming energy to users on the ground...

Try making that argument WITHOUT begging the question.

For comparison lets look at a Boeing 757. It travels 6,267 km on
43,400 liters of jet fuel. That's' 1,375 GJ per fill up. The Earth
is 40,000 km in circumference - so, that's 6.38 refuelings to travel
around the world - a total of 8,776 GJ. The payload of a 757 is
about 30 tons - so that's 292 GJ per ton carried around the world.
Over 10X the energy of an orbiting payload.

Great, so you're comparing the energy used transporting things to space,
which you falsely assume can be 100% efficient, to one of the least
efficient modes of transportation used on Earth. Why don't we routinely
transport tonnes of construction materials by 757,? We do it on rails
and ships, where the transportation and energy cost is a small fraction
of what you've stated.

On Aug 7, 12:40*am, Hugh Gibbons
wrote:
In article
,

wrote:
Orbital velocity is 7 km/sec *- that means a metric ton of material on
orbit contains

* * E = 1/2 * 1,000 * 7,000 * 7,000 = 24.5 GJ

That's the wrong energy. *

No its not - the major part of the energy needed for space travel is
the kinetic energy. Orbital energies are on this scale - which is
less than air-travel. that was my point.

Now, removing something to infinity from Earth's surface only doubles
that energy requirement when compared to LEO - BOTH are kinetic
energies.. haha.. I was going to add that but thought you would get
the point anyway - especially since I didn't use this particular
figure to obtain the dollar figures I used later.

haha.. I'm a rocket scientist dude, if I wanted to be pedantic about
it - you're not using the 'right figure either' - but I wouldn't say
that right off the bat, cause I don't have an overwhelming need to
tell people they're ****ed - just so I can feel better - haha. like
you do.

Fact is, since you brought it up - the real energy figure is more
complex (though is still kinetic energy energy). You take the
propellant weight aboard a space vehicle and figure out the kinetic
energy of all that propellant moving at its exhaust velocity. Still
using E = 1/2 m V^2 but in this case,m is the mass of propellant, and
V is the exhaust velocity. haha - the mass is computed using the
Tsiolkovsky equation and your final delta vee. You figure your
vehicle cost according to structural mass - and all that - but that's
WAY over the top - besides all the real numbers SCALE WITH ORBITAL
ENERGY -once you go through all the details. Take orbital energy
equal to 1 and you find that escape energy is equal to 2 - and GTO as
well as GEO is somewhere between 1 and 2 - and then you use calculus
of variations - haha - to optimize your total propellant energy and
staging once you set up the differential equations of motoin - lol -
which for chemical propellants is still a factor less than 5 - WHICH
IS STILL LESS THAN THE ENERGY IT TAKES TO FLY LONG DISTANCES THROUGH
THE AIR.

We're not talking about orbiting power
satellites at 1700 kilometers altitude.

So? My point still stands. Space travel throughout cislunar space -
scales with theenergy it takes to orbit the Earth. Just because I
didn't launch into a freaking discussion of orbital mechanics and
rocket science doesn't mean the number is wrong. haha. Not only is
it the right number to use to get a sense of the scale of the problem
- it is kinetic energy throughout - that we're dealing with.

Fact is, something in GEO requires a total velocity less than escape
velocity - which is less than 11 km/sec which is less than double this
energy figure. Even if you double the figure I computed earlier- that
number its still less than the energies needed for long distance air
travel.

The point I was making is that placing something into oribt or GTO or
GEO with today's technology is around $10 milion per ton using
expendables and if we did it a lot with optimally engineered reusables
it would drop to $500,000 per ton - after a dedicated engineering
effort costing less than 10 nuclear power plants. lol. Again, just
because I didn't quote AIAA articles on air versus space transport
costs doesn't make the figures wrong - it just means I wanted to get
to the frfeaking point.

*We were talking about geo.

Which is still on the same freaking order of energies. You can
project something to infinity at 11 km/sec - to go to the moon
requires 10.85 km/sec - haha - fact is, I forgot what GEO and GTO
velocities were - and didn't want to use escape velocity because I
figured you'd jump all over that since we're not escaping the Earth -
and I remembered GEO. haha.. My point stands - the energy it takes
to orbit the Earth and navigate around the Earth is FAR LESS than the
energy it takes to travel long distances through the air.

What about long distances through the ocean?

http://people.bath.ac.uk/ccsshb/12cyl/

This ship consumes about 2,600 gallons of fuel per hour to operate.
It travels about 20 kph - so to travel 40,000 kmr requires 2,000
hours. takes about 700 hours to travel across the ocean and back -
that's 5,200,000 gallons. That's 631 million million joules. 94,000
tons payload means that each ton requires 6.5 GJ of energy to
transport a ton around the world this way.

Again this is merely an estimate of the scale of the problem of
floating something across the ocean - haha - which is 1/5th the energy
conained in orbiting that ton - which scales the spaceflight problem -
but less than air travel!

.What about trucks?

http://www.kenworth.com/FuelEconomyWhitePaper.pdf

16 metric tons and 8 kilometers per gallon means to send 1 ton 40,000
km by truck mean you're spending 37.8 GJ of energy to transport
something around the world by trruck. This is about what it takes to
send something to orbit. LESS than air travel - more than sea travel.

So for Wally-world to ship something from inland China to inland North
America takes about as much energy per metric ton - as sending it to
orbit - which is the fundamental physical principle which scales the
space flight problem. Air is way more expensive.272 GJ/tonne - but
space travel is somewhere in between.at 24.5 GJ to 49 GJ for escape -
depending on details - and with today's rockets - about half the
energy required to carry something by air around the world when you go
through all the details..

*At
geo, the kinetic energy is only 4.7 GJ/tonne.

haha - you're the one using the wrong figure - and you're blaming me
for your freaking mistake!. You've totally ignored the point and
gotten the wrong one instead. You freaking moron! lol.

You've got to look at the TOTAL delta vee between Earth's surface and
wherever it is you're going. Toss a ball into the air - its height
will scale with the square of velocity. haha - or its energy - E = mgh
= 1/2 m V^2..

And you're the one blathering about people who don't understand basic
physics? Velocity of space travel (and the amount of time you have to
attain that velocity) is what scale the space travel problem
physically.

Speed - in a gravity field - is needed to gain altitude as well as
stay at that altitude you freaking idiot. You're just looking at the
staying part and blaming me because you didn't get my point. lol..

This doesn't change my point - everything scales with orbital
velocity. Total energy is greater the higher you go - true - despite
the fact orbital speeds are lower to stay there once you get there.
haha - orbiting at the surface - or at LEO above the atomosphere -
SCALES the problem.

Escape velocity (going to infinity) is double the energy at LEO in a 1/
r^2 field - which is on the same SCALE as LEO.

*That doesn't mean it's
cheaper to get things to geo than LEO. *

That's why I never said that. You did. I said it takes AT LEAST 24.5
GJ per metric ton to get into space - (due to other considerations NO
MORE than 100 GJ) - which is LESS than sending things by air around
the world. So, there is no reason in principle that it MUST be more
expensive to send things into space than to send things around the
world by air.

You also have to lift the mass
to the orbital altitude. *

That's absolutely true - why does my failing to mention orbital
mechanics or even rocket mechanics change the point I'm making? The
problem of space travel is the problem of getting into space -
attaining LEO is the first step - which requires at least 24.5 GJ per
metric ton everything is rather easy after that..

Besides, you haven't answered my freaking question - what is your
fundamental physical principle that makes space travel 100x more
expensive than sending parts and people to different places on Earth?
And why is 100x more expensive the right number and not say 83? or
105? hmm?

You're the one who is a freaking moron who doesn't have a damn clue
about the numbers he's throwing out. ANSWER MY ****ING QUESTION MORON
- My damn number has more relevance behind it than anything you've
said - asshole! - haha..

To get to orbit at all, you must deliver
energy of 32 GJ/tonne, and that's way too low to be practical (200 km).

32 GJ is only 30% greater than 24.5 GJ - NOT 100 TIMES LIKE YOU SAID.
They're nearly the same when compared to sending something by air
around the world - which is far greater. Besides, did you take the
air drag and gravity drag losses into account? My number is not
wrong - haha - since I said it scales the problem - which it does. 32
GJ/tonne is on the same scale as 24.5 GJ/tonne - your number is not
100x more energy than anything we can do on the surface of the Earth -
in fact the number is on par with sending stuff overland by truck -
which is something we do every freaking day. Anything we do on Earth
requires that we send people and materiel to a spot on Earth and
supply them and bring them back - which is about the same amount of
energy.

You are indeed a very stupid person. I mean, THINK ABOUT WHAT YOU
SAID AT THE OUTSET. You said;

1) you can't change fundamental physics (true) ;

2) fundamental physics REQUIRES space travel to be 100x more
expensive than ANYTHING you can do on Earth.

Okay, WHAT is that fundamentla physical principle? WHY is is
necessarily100x more expensive than ANYTHING we can do on Earth?

The only thing about space travel is the tremendous speed involved.
This scales the energy needed. That's a fundamental principle. In
fact I'm saying that is the fundamental principle -and I'm telling you
its not 100x the energy needed to send stuff around the world by
conventinoal means.

So, look at the energy needed for both. You need somehing around 24.5
GJ/tonne. You say I'm wrong and hen calculate 32 GJ/tonne - haha -
and that's the right energy? haha!

I hate to say it dude, 32 is not 100x 24.5 - besides, 32 and 24.5 GJ/
tonne are both LESS than sending stuff by truck or air arond the
world! Both of those are something we do on Earth - and you said
anything in space is 100x more costly than anything we do on Earth due
to fundamental physical principles.

So,IS the amount of energy needed to send stuff into space the
fundamental principle you were talking about? If so, where did you
get the factor of 100???? If not WHAT physical principle ARE you
talking about?

To project something to escape velocity requires no more than double
minimum orbital velocity -
*
To get to the altitude you were describing, where orbital velocity is
7km/sec, it's 37.5 GJ/tonne and at geo it's 57.3 GJ/tonne.

When you circularize the orbit - yes - did you account for air drag
and gravity losses during the burn? This figure is still less than
air travel - something you do on Earth - and about the same as hauling
stuff by truck over rough terrain or rough seas by cargo ship for that
matter (fuel economy sucks when you're fighting a current, rough seas,
and storms).

Space travel by this measure is NOT 100x ANYTHING WE DO ON EARTH -
which is my freaking point. Compared to 1/100th the figure you
mention - 24.5 GJ/tonne is neearly the same number - the figure you
mention is equivalent to hauling something around the world within an
order of magnitude - not two orders of magnitude larger.

So, despite your quibbling - you still have lost the point.

That's about the energy content of a ton of coal, or 200 gallons of
gasoline., *So, this costs between $70 and $800 depending on what sort
of fuel you use. *

No it doesn't, because space propulsion is not that energy efficient.

The thermal efficiency of a rocket engine is higher than the thermal
efficiency of a truck engine or the thermal efficiency of an aircraft
engine.

The fuel that must be used to accelerate a mass to these velocities is
many times what your assumptions say.

Not 100x the figure - which is what you said. The actual figure would
go something like this... Take a two stage to orbit vehicle with a
third kick stage. Lets say we've got 15% structural fraction for each
stage. orbital velocity is 7 km/sec - with air drag and gravity
losses - 9 km/sec - exhaust velocity 4.5 km/sec. sigh alright lets
look up the delta vee for GTO... lessee - the Vis Viva equation for
the delta vee required is 31.5% orbital velocity at LEO - or 2.45 km/
sec. At apogee you need to impart 52% of the orbital velocity at GEO
- or 1.60 km/sec there.

using

mu = 398,600 km3/sec2 for Earth
r = 6,366 km + 234 km alt = 6,600 km
a = 42,164 km

So, our stage velocities are;

Stage 1 - 4.5 km/sec
Stage 2 - 4.5 km/sec
Stage 3 - 2.5 km/sec
Satellite - 1.6 km/sec

Assuming exhaust speeds of 4.5 km/sec and a structural fraction of 16%
- and working backwards using the rocket equation - one ton at GEO
means

u = 1/EXP(Vf/Ve)

Satellite u=0.300 s=0.160 --- p = 0.540
Stage 3 u= 0.427 s=0.160 --- p = 0.413
Stage 2 u= 0.633 s=0.160 --- p = 0.207
Stage 1 u = 0.633 s=0.160 --- p= 0.207

alright, this means that to put 1 ton to GEO requires

Stage 3 payload = 1/0.540 = 1.85
Stage 2 payload = (1/(0.540* 0.413)) = 4.49
Stage 1 payload = 21.66
GLOW = 104.64

Alright - haha - so, now lets figure out the propellant at each stage

Stage 1 0.633 * 104.64 = 66.2 tonnes
Stage 2 0.633 * 21.66 = 13.7 tonnes
Stage 3 0.427 * 4.49 = 1.9 tonnes
Satellite 0.300 * 1.85 = 0.6 tonnes

Adding up all this propellant - 82.4 tonnes. This is hydrogen/
oxygen. The exhaust speed is 4.5 km/sec. So the total energy
imparted to this propellant is

E = 1/2 * 82,400 * (4,500 * 4,500) = 834.3 GJ

Which is FINALLY bigger than anything we do on Earth - but not by
much! - certainly not 100x bigger than Earth transport energies -

Besides you elided all my analysis after this when I got into costs.
You decided to harp on your foolish point which merely obscures the
fact you were wrong in your statement that there was a fundamental
physical principle that required space travel to be 100x more
epxensive than anything we do on Earth..

Fact is, I gave you the 100x factor in my further anaysis - $10 milion
per tonne cost ain't cheap - and that's where i started. Then, went
on to show you can make very light weight satellites - like Echo 2 -
to form concentrators and beam laser energy efficiently to terrestrial
systems- and you just ignored it preferring instead to carp rather
than take my quite valid point about costs..

But lets continue - with a complete analysis of energies.

82.4 tonnes of hydrogen/oxygen has a chemical potential of 1,309.2 GJ
which is 57% more energy than is imparted to the propellant! Making
the rocket engine 64% efficient - the balance is frozen flow losses in
the hot gases.

This is WAAY more efficient than a truck engine or a diesel/electric
engine on a ship, or an aircraft engine.

Even so, because the exhaust speed is not well matched to the terminal
speed you lift a lot of propellant - about 7.2% of the kinetic energy
in the exhaust gases and 4.6% of the potential energy of the
propellant - ends up in the orbiting payload.

The fix to this is easy to see if we take Ve = 14.7 km/sec and do
everything in one stage - imparting 14.1 km/sec to the payload - and
then deorbiting the vehicle after releasing the satellite;

u = 1 - 1/exp(14.1/14.7) = 0.617 s=0.16 -- p = 0.223

The propellant needed to slow down the booster once on orbit is 0.006
times the total mass - so, increasing u to 0.625 reduces payload 0.215

This means that the gross lift off weight GLOW - is 4.65 metric tons
for every metric ton of payload on orbit. Of this 2.90 metric tons is
propellant. Ejecting this at 14.7 km/sec means we impart 313.3 GJ per
metric ton of payload - and assuming a 70% engine efficiency (higher
speed equal higher temps mean higher pressure ratios, and higher
efficiencies) - 447.6 GJ per metric ton of payload.

Still lifting a lot of propellant - but not nearly as much - we've
basically doubled our efficiencies.

But even using our lower efficiencies - this is on par with the
efficiencies of other human endeavours - when we analyze the payload
energies and take them as a ratio of say - primary energy - including
all the energy it takes to move fuel. In fact in aircraft the range
equation is very similar to the rocket equation.

Of course, if you use laser or maser energy beamed
from space cheaply in the first place, the costs could be
substantially less! * In fact getting the energy costs to about 1% of
what they are today by beaming energy to users on the ground...

Try making that argument WITHOUT begging the question.

?? would you be cleearer about what your objection is? Clearly your
statement that doing anything in space is 100x more expensive than
doing anything on orbit due to fundamental physics - is bogus. Please
explain that.

Fact is, with thin film concentrators, and highly efficient free
electron lasers beaming band gap matched energy to terrestrial
receivers at 400 W/m2 - can achieve very cost efficient operation -
higher intensity lasers have been shown to operate rockets efficiently
with 15 to 20 km/sec exhaust speeds with quite inexpensive plastic
propellants.

http://adsabs.harvard.edu/abs/1992spte.symp....1O

For comparison lets look at a Boeing 757. *It travels 6,267 km on
43,400 liters of jet fuel. *That's' 1,375 GJ per fill up. *The Earth
is 40,000 km in circumference - so, that's 6.38 refuelings to travel
around the world - a total of 8,776 GJ. * The payload of a 757 is
about 30 tons - so that's 292 GJ per ton carried around the world.
Over 10X the energy of an orbiting payload.

Great, so you're comparing the energy used transporting things to space

Yes because YOU said anything we do in space is 100x more costly than
anything we can do on Earth because of fundamental physics. So, I
compared one fundamental physical measure - the energy contained in an
orbiting object - and I am showing the SCALE of the problem is the
same.
,
which you falsely assume can be 100% efficient,

No I didn't - you falsely assumed that - I didn't. I merely gave the
scale of the problem - root mu over r - the factor in the vis-viva
equation to compute the velocities to all other orbits. where mu is
the gravitational parameter of earth and r is earth radius. haha -
you read that and run off at the mouth - adding some small altitude to
earth radius and calculating a slightly different number - all the
while forgetting what you said - 100x - yeah right.

to one of the least
efficient modes of transportation used on Earth.

You're the one who said ANYTHING - air travel is something we do on
Earth - now you're trying to make an issue of it? You're a freaking
idiot! lol.

*Why don't we routinely
transport tonnes of construction materials by 757,

Do we? Don't we? Its a matter of degree - not absolutes. I am
certain at some point in time a 50 lb bag of concrete mix got put on
an airplane - or a load of 2x4s - in fact I'm certain of it - if you
look at what it took to build the base at the South Pole.

Even so, who said we were going to build power satellites out of
concrete and steel? Not me. So what's you're point bubba? lol.
From what I can see, you're in over your freaking head! You don't
have a point because you can't follow the freaking argument.

Thin film concentrators, illuminating multi-band PV cells, driving
MEMs based FELs at high efficiency, beaming band gap matched laser
energy to receivers on Earth - are cost effectrive even if you accept
a $10 million per ton placement cost - and that likely will drop to
less than $500,000 per ton if you organize yourself to build and place
hundreds of powersats on orbit every year.

? *We do it on rails

Not over the ocean we don't. - steel rails and steel wheels are still
the most efficient means to move things - you've still got winds,
freezing conditions, snow, mountain ranges - that cause inefficiencies
though - so even rails as efficient as they are - in the real world
through real weather - they're not a factor of 100 cheaper than space
travel.

and ships,

Yep - and we just saw that there all within an order of magnitude of
each other - YOU ARE THE ONE WHO SAID SPACE TRAVEL IS 100X AS COSTLY
AS ANYTHING WE CAN DO ON EARTH - air travel is something we do on
Earth - live with it.

where the transportation and energy cost is a small fraction
of what you've stated.

I merely showed that on a fundamental physical basis - the energies
needed for spaceflight were not a factor of 100 different than
transport on Earth - which shoots in the head your BOGUS statement.

Ii never used that figure to calcualte cost. I ACCEPTED A $10 MILLION
PER METRIC TON COST - and then calculated what you could do with that
- something you erased in your response.

A more complete analysis of rocket and payload energies obscure the
point - even if you do an accurate analysis using the tsiolkovsky and
vis viva equations - you're not out there by a factor of 100x above
say air travel- SO YOU WERE WRONG SPONGE BOB! LOL.

So,l am still waiting to hear - what is the fundamental physical
principal that makes spaceflight 100x more costly than anything
(including air travel) we can do on Earth?)

Fact is you can't come up with one - because there is none.

"Hugh Gibbons" wrote in message
...
In article
,
wrote:
That's about the energy content of a ton of coal, or 200 gallons of
gasoline., So, this costs between $70 and $800 depending on what sort
of fuel you use.

No it doesn't, because space propulsion is not that energy efficient.
The fuel that must be used to accelerate a mass to these velocities is
many times what your assumptions say.

Oh? What's so expensive about rocket fuel?

LOX and kerosene is not nearly as expensive as you think.

Space may be expensive, but it's hardly the cost of fuel that's driving it.




--
Greg Moore
SQL Server DBA Consulting Remote and Onsite available!
Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html

On Aug 7, 7:30*am, "Greg D. Moore \(Strider\)"
wrote:
"Hugh Gibbons" wrote in message

...

In article
,
wrote:
That's about the energy content of a ton of coal, or 200 gallons of
gasoline., *So, this costs between $70 and $800 depending on what sort
of fuel you use.

No it doesn't, because space propulsion is not that energy efficient.
The fuel that must be used to accelerate a mass to these velocities is
many times what your assumptions say.

Oh? *What's so expensive about rocket fuel?

LOX and kerosene is not nearly as expensive as you think.

Space may be expensive, but it's hardly the cost of fuel that's driving it.

On 7 Aug, 15:46, wrote:
On Aug 7, 7:30*am, "Greg D. Moore \(Strider\)"





wrote:
"Hugh Gibbons" wrote in message

...

In article
,
wrote:
That's about the energy content of a ton of coal, or 200 gallons of
gasoline., *So, this costs between $70 and $800 depending on what sort
of fuel you use.

No it doesn't, because space propulsion is not that energy efficient.
The fuel that must be used to accelerate a mass to these velocities is
many times what your assumptions say.

Oh? *What's so expensive about rocket fuel?

LOX and kerosene is not nearly as expensive as you think.

Space may be expensive, but it's hardly the cost of fuel that's driving it.

--
Greg Moore
SQL Server DBA Consulting * * * * * Remote and Onsite available!
Email: sql *(at) *greenms.com * * * * *http://www.greenms..com/sqlserver.html

That's why in my analysis is accepted the $10 million per ton cost but
allowed that with appropriate investment it could drop to $500,000 per
ton.

In addition to addressing the cost of power from space - I also was
addressing the foolish statement that there are fundamental physical
reasons space MUST be 100x more expensive than ANYTHING we do on
Earth! *lol. * So, I took a fundamental physical value - and showed
that it wasn't 100x as great as things we do on Earth.

You are right. *I showed in a later post that to put 1 ton into LEO
with a hydrogen/oxygen chemical rocket - in a manner so all stages
were *reusable - you'd use something close to 90 tons of propellant -

At $5,000 per ton for the propellant - you'd have $450,000 propellant
cost - *you have something like 15 tons of vehicle. *At $500,000 per
ton that's $7.5 million - *add another $2 million per ton for
construction cost, and launch operations - and that's you're $10
million. * Reuse the spacecraft 500 times with 0.2% maintenance and
refurb cost - and that $7.5 million per launch falls to *$30,000 per
flight ton - and costs drop to $500,000 per ton - while construction
and launch operations drop to $1 million per ton due to learning curve
effects. * So, we start out with $10 million per ton and drop to $1.5
million per ton - for the total system with launch costs making up
$9.5 million at the outset and dropping to $1 million over time.

Now, a square kilometer of light weight satellite using thin film
concentrator disk 1.16 km in diameter illuminating a multi-junction PV
cells - and MEMs based FELs and optics - operating at 2,500x solar
intensity - gives you a PV area and window area of 400 square meters -
a circular apeture 22.6 meters in diameter - for a 1 sq km
concentrator and masses 20 metric tons *- and beams 420 MW of laser
energy to receivers on the ground totalling 1 sq kilometer in area.

The space based portion ranges in cost from $200 million early on to
$30 million later. *This is $0.48 per watt for the space portion eary
on to $0.07 later on.

The ground based portion costs $12.6 million per square klometer using
my ultra-low-cost solar panel technology

http://www.usoal.com

This technology generates 180 MW per square kilometer from sunlight,
and without solar panels generates 306 million kWh per year. *To keep
balance of system costs low those panels are used to generate hydrogen
and oxygen at a rate consistent with lighting conditoins using water
as a feedstock. *Used in this way each square kilometer produces 5460
metric tons of hydrogen per year.

Trading 3410 metric tons of hydrogen for coal - and burning that
hydrogen in a coal fired power plant - displaces 21,140 metric tons of
coal and eliminates 66,500 metric tons of carbon dioxide each year -
for each square kilometer. *Combining the remaining 2,050 metric tons
of hydrogen with the coal obtains 152,200 barrels of gasoline each
year, along with 4,000 tons of asphalt each year.

Now the value of all this is;

* *CO2 avoidance
* *66,500 x $10/tonne = $665,000

* *Asphalt production
* *4,000 x $200/tonne = $800,000

* *Electricity
* *51.3 million kWh x $0.04/kWh = $2,052,000

* *Liquid fuel production
* *152,200 bbl x $150/bbl = $22,830,000

Well worth the $12.6 million investment!!

The $26.3 million per year over 30 years represents $790.1 million in
value. *LESS than the $200 million early on costs of putting up a 1 sq
km power satellite.

The CAPEX of coal handling and conversion equipment is $340 per metric
ton per year of coal processed. * So, that's $7.2 million per square
kilometer of terrestrial panels.

There are of course non-recurring engineering charges - $1.2 bilion
for the terrestrial solar panels (to build the factory) and $6 billion
for the power satellite (to build the factory to build the rocket and
satellites) - that's $7 billion.

You need to plan something like 480 sq km of terrestrial panels.and
200,000 b/d per day - with 5 billion tons of coal dedicated to the
project processing 30,000 tons of coal per day with the following
costs;

* * * *$6.0 billion solar receiver
* * * *$3.4 billion coal processing
* * * *$1.2 billion solar supply chain

* * *$10.8 billion total terrestrial unit - 480 sq km.

Which produces a value of

* * * 200,000 b/d x 365.25 d x $150/b = $11.0 billion per year

The value of an asset that produces this much revenue for 30 years -
in an era of rising oil prices - yeilds $330 billion in value.

A 30 year life span - this represents $330 billion value! * Taking 5
years to build out the system, and applying a 40% discount rate
(venture capital returns) on the first portion produces a value today
of $23.3 billion - not counting for oil price rises. *So, by selling
46.3% of this facility for $10.8 billion - the needed capital is
raised,and provides as 40% annualized rate of return on capital.

The project sponsor owns 53.7% of the project and at first day's
production this is worth $177.2 billion

A 480 sq km satellite masses 9,660 tons. * Doing this in a single
satellite - we produce a circular apeture 24.7 km in diameter.
Operating at 10,000x solar intensity - the PV/FEL/Window portion is
247 meters in diameter and beams 196.7 GW to the receiver.

The launcher masses nearly 1 million tons - and is launched from an
equatorial region in the Pacific Ocean (a small island in Indonesia)

There is a NRE charge of $10 billion to design these systems. *Another
$7.5 billion is used to build each power satellite. $72 billion is
used to build each launcher - two reusable launchers are built and the
fleet places 3 satellites per year. *Additional terrestrial plants are
built to use the additional satellite output.

The 9,660 ton satellite costs $100 billion at first and drops to half
that as experience is gained. 180 billion watts of energy is delivered
to the ground based site 24/7 - increasing hydrogen output by 28.2
million tons of hydrogen per year 16.2 million tons of hydrogen are
used to increase the oil output 3.2 million bbls per day - electrical
output is increased to 75 GW - using process heat and hydrogen- and 12
milion tons per year of spare hydrogen is sold directly - the
equivalent of 800,000 barrels of oil per day.

* * Oil + hydrogen
* * 4 million bbl/day oil equiv x 365.25 x $150 = $219 billion/yr

* * Electricity
* * 75 million kW x 8,766 hr/yr * $0.04/kWh = * * $26 billion/yr

This is about a quarter of a trillion per year. *The project takes 5
years on top of the other project, and is fully funded from internal
sources. *At the end of the day,3 satellites are orbited per year -
These systems tie up 5 billion tons of coal per installation and take
about 500 sq km.

The Earth uses 84 million bbls/day of oil - so dividing this by 4
obtains 28 stations and 140 billion tons of coal (the US alone has 285
billion tons of easily recoverable coal) and 14,000 sq km of
collectors. *At 3 per year - this will take less than10 yeas to put
into place. *Each rocket will have been flown 14 times - and with a
500 flight cycle life time - they can continue to fly to build up
capacities for hydrogen alone, and ultimately, beamed power directly.

These large launchers are also used to do deep space exploration and
planetary development and industrialization.

The nice part is that its all self funding -fromthe first $120 million
- and it takes 15 years - to displace all the energy use on Earth -
and capture the $4 trilion per year market. *The conventional fuel
market won't disappear in the interim. *At 4% annual growth, the
market will be 180% the size it is today in 15 years. *So,
conventional energy will be shipping 80% of the total at that time -
which is consistent with oil output peaking in 2010-12 time frame.

Subscale test articles capable of putting up 100 tons and 500 tons -
would also do useful work. *Placing large satellite networks on orbit
- for global communicatoins, and as supply and staffing fleets to
support the larger payloads lofted by the 'freighters'

While 10,000 tons payload and 1,000,000 ton GLOW is large by
historical standards, it is typical for ocean going craft.

Its really where we need to be to get costs under control.

The fact of the matter is though that you do not need heavy
indivisible loads for SSP. In fact you can phase lock a large number
of small units to give you the total Terawatts you need.

One thing, apart of course from cheaper material to LEO, that would
reduce cost is the production of the largest part of the mass in
space. In short you need to smelt aluminium on asteroids to provide
the reflectors and the back mountings. Production of the solar cells
themselves is pretty high tech and will only be possible on Earth for
some time yet.


- Ian Parker

On 7 Aug, 15:46, wrote:

Now, a square kilometer of light weight satellite using thin film
concentrator disk 1.16 km in diameter illuminating a multi-junction PV
cells - and MEMs based FELs and optics - operating at 2,500x solar
intensity - gives you a PV area and window area of 400 square meters -
a circular apeture 22.6 meters in diameter - for a 1 sq km
concentrator and masses 20 metric tons *- and beams 420 MW of laser
energy to receivers on the ground totalling 1 sq kilometer in area.


This is a perfect example of the kind of half-baked thinking involved in
these proposals. Photovoltaic cells won't withstand 2500x solar
intensity ( 1372 W/m2 x 2500 = 34.3kW/m2 ). That would heat the PV to
well above silicon junction breakdown temperature, or for that matter
that of any semiconductor. To operate PV at significantly below the
breakdown level, you must keep junction temperature below 200C, which is
473K. Counting the front and back side of your flat panels, you have a
radiating surface that's 2x that of the collector itself, so the
radiating area is 2x the collector area. If you are getting 20%
efficiency, that means you only have to radiate off 80% of the incoming
solar power to space, so you only have to radiate off 3.5kW/m2. Since
the collector area is 2x the radiation surface, that means you can
concentrate incoming light to 7.0kW/m2, so the concentration factor is
5.1 to 1. You might be able to improve that a little by using higher
efficiency PV cells.

Keep in mind that for silicon junctions, what I'm describing here is
right at the edge of accelerated thermal breakdown. You have to keep
below that level or you severely compromise operating life.

So you're only off by a factor of 500 on the concentration factor and
the mass that must be moved to orbit and the cost of the system.

In article ,
"Greg D. Moore \(Strider\)" wrote:

"Hugh Gibbons" wrote in message
...
In article
,
wrote:
That's about the energy content of a ton of coal, or 200 gallons of
gasoline., So, this costs between $70 and $800 depending on what sort
of fuel you use.

No it doesn't, because space propulsion is not that energy efficient.
The fuel that must be used to accelerate a mass to these velocities is
many times what your assumptions say.

Oh? What's so expensive about rocket fuel?

LOX and kerosene is not nearly as expensive as you think.

Space may be expensive, but it's hardly the cost of fuel that's driving it.

It's not the price. It's the amount required, which is many times what
Mookie claimed.

In article
,
wrote:

where the transportation and energy cost is a small fraction
of what you've stated.

I merely showed that on a fundamental physical basis - the energies
needed for spaceflight were not a factor of 100 different than
transport on Earth - which shoots in the head your BOGUS statement.

Maybe it's not necessarily 100 times as expensive. That was a ballpark
figure and why you got wrapped around the axle over it is beyond me. If
it was only 5 times or 10 times as expensive, or only 2 times more
expensive to achieve the same goal, that's still prohibitive and means
it won't happen.

There were basic errors in your calculation of the work required to put
things in orbit, and out of sheer laziness or for all I knew, your
possilbe lack of comprehension, you left it out, and you came out with a
wrong result, albeit within a factor of 2 of the actual work required.

My figures are much closer, because I DID bother to carry out the
gravity potential computation as well as the actual kinetic energy
associated with orbital velocities.

Ii never used that figure to calcualte cost. I ACCEPTED A $10 MILLION
PER METRIC TON COST - and then calculated what you could do with that
- something you erased in your response.

I don't feel compelled to quote everything you said. I only quote those
on which I wish to comment. Everything else is referenced in the
article. I did not erase the reference to your article, and I didn't
distort anything you said, so you have nothing to complain about.

10 million dolllars per metric ton is what, about 10,000 times the cost
of shipping from almost anywhere on Earth to almost anywhere else, isn't
it. So building things in space is incurring a minimum of a $10M/tonne
cost adder and that's awfully hard to overcome. Building on Earth is
cheaper.

A more complete analysis of rocket and payload energies obscure the
point - even if you do an accurate analysis using the tsiolkovsky and
vis viva equations - you're not out there by a factor of 100x above
say air travel- SO YOU WERE WRONG SPONGE BOB! LOL.

No, they don't obscure the point. That's essential to any discussion of
the feasibility of building massive structures in space. It multiplies
the amount of energy required to lift objects to orbit by about 10x,
does it not? That's part the physical laws you are working with that
add cost.

And that is not the only cost adder of building in space. Everything
costs more, because tools and workforce must also be brought from Earth
at huge costs, and the workforce must live there for the duration of the
project, so you have to build large space stations, provide for food,
air, space suits, etc. And you must contain your work area somehow so
that your materials don't all drift away and become a field of orbiting
space junk. That's all part of that ballpark 100 times I was talking
about.

On Aug 7, 7:25*pm, Hugh Gibbons
wrote:
On 7 Aug, 15:46, wrote:

This is a perfect example of the kind of half-baked thinking involved in
these proposals. *Photovoltaic cells won't withstand 2500x solar
intensity ( 1372 W/m2 x 2500 = 34.3kW/m2 ).

I've built cells and tested them - and those tests are confirmed by
independent laboratory testing - to 2,500x solar intensity.

*That would heat the PV to
well above silicon junction breakdown temperature,

Why? You are making a large number of erroneous assumptions here.
haha.. That would make your objections here 'half baked' wouldn't it!
lol.

or for that matter
that of any semiconductor. *

Depends on the details. At 1 solar in space you have 136.6
milliwatts per square centimeter. At 2,500x that intensity you have
341.5 watts per square centimeter. Properly loaded a 6 junction cells
consisting of germanium, four types of gallium arsenide and indium
phosphide, converts 40% of that energy to electrical energy which
leaves the system. 20% of the energy is reflected by dichroic film
that produces a bandpass filter - to reflect away ineffective light
(see my patent on this subject for more details)

http://www.patentstorm.us/patents/7081584/claims.html

this leaves 40% of the total energy - that must be efficiently removed
to maintain the design temperature.That's 136.6 watts per square
centimeter. Modern heat sinks routinely handle 150 to 200 watts per
square centimeter.

http://www.reuters.com/article/press...08+PRN20080318

http://www.innovations-report.de/htm...cht-15104.html

To operate PV at significantly below the
breakdown level,

Junction temperatures of about 110C are used in my systems - I use
water - as a coolant and as a lensing medium. The water flows over
both sides of the PV device, so, heat sink rates are less than 70
watts per sq cm of collector surface - since I'm illuminating from one
side, and cooling from both.

you must keep junction temperature below 200C, which is
473K. *

That's right, and a careful analysis of heat balance is required in
order to determine what's possible. You obviously have not done that.

Counting the front and back side of your flat panels, you have a
radiating surface that's 2x that of the collector itself, so the
radiating area is 2x the collector area. If you are getting 20%
efficiency,

I'm getting 40% efficiency and reflecting away 20% of the spectrum
that doesn't operate the cell at all.

that means you only have to radiate off 80% of the incoming
solar power to space,

That means I must remove 40% - of the heat - less than 70 watts per sq
cm - through my heat exchanger - to a larger surface. Recall, in
space here, I'm using two sheets of thin film - one transparent the
other not - that's got over 10,000 sq cm for each sq cm I illuminate
(the films are spherical not disk surrfaces) - recall the 'targe' is
attached to a concentrator which has a very low pressure atmosphere
and a very large surface area.

So, we have a little less than 140 watts per square centimeter being
radiated into 10,000 sq cm - 1 square meter for each sq cm. The
temperature of a black body radiating at 140 watts per square meter is
easily computed by the Stefan Boltzman Law

j = sigma T^4

j = 140 W/m2
sigma = 5.67e-8

T = (140/5.67e-8)^(1/4) = 221.6 K

Below the freezing point of water.

Actually since the water has other stuff in it, and the radiator isn't
perfect,

so you only have to radiate off 3.5kW/m2. *

you're operating at 3.5 MW per sq m- you did the calculation wrong.
And you only have to sink 136.6 watts per sq cm - the rest is either
reflected away or extracted by the circuit. Water flowing over the
cells achieves this - actually surface areas are larger. Now the
110C water is something else - that gets evaporated into the cavity of
the inflatable optics. And condenses onto the surface. Which is
structured to return the water - like a big heat pipe - to the source
- there's no gravity - but there is surface tension, and dispersion -
and this system in numerical studies seems to work rather well - and
when we build test articles - they perform as expected.

Since
the collector area is 2x the radiation surface, that means you can
concentrate incoming light to 7.0kW/m2, so the concentration factor is
5.1 to 1.

Only if you let the PV target cool by radiation into the vacuum.
since you've got a big ass collector,,why not use it to radiate
energy?

*You might be able to improve that a little by using higher
efficiency PV cells.

and reflecting away ineffective photons - and using some sort of heat
exchanger to efficiently use the collector balloon's surface to
radiate away the heat.

Keep in mind that for silicon junctions, what I'm describing here is
right at the edge of accelerated thermal breakdown. *You have to keep
below that level or you severely compromise operating life.

Well before that happens the semiconductor becomes conductive. We
operatae at 110C - which is 383K - at the hot side - and we retrieve
the water at around freezine 273K approximately.

So you're only off by a factor of 500 on the concentration factor

No, YOU are off by a factor of 500 because the system you imagine is
absolutely stupid! Why the hell would you let the heat sensitive PV
device be your heat radiator? lol. Idiot.

and
the mass that must be moved to orbit and the cost of the system.

Nonsense. You save mass by letting each gram of mass you do send up
be as useful as possible. The water vapor contributes to the
collector's inflation as well as cooling the PV device which operates
at 110 C