John Pazmino
 NYSkies Astronomy Inc
 2008 November 7 initial
 2009 Septenber 6 currebt
    One of the earlier potential applications of humankind's newfound 
ability to work in Earth orbit was the solar power satellite. In the 
mid 1960s, before the Apollo flights, a basic scenario was put out by 
several spacefaring agencies and advocates.
    There would be in geostationary orbit an immense field of solar 
panels to generate electric. The accompanying satellite wold convert 
the electric into a microwave beam to send to a receiving base on the 
ground. This receiving base would convert the microwaves back to 
electric and feed it to the local power network. 
    Many studies were made over the years, thru the 20-thous, by NASA, 
US Dept of Energy (DOE), US Dept of Defense, universities, and 
aerospace companies. 
    In October and November 2008 Paul Roseman, National Space Society, 
gave two talks on the solar power satellite, outlining today's 
prospects. The first was at the Sharp dance club in Chelsea on October 
3rd. The next was on November 6th at the NYSkies-NSS Seminar. 
    Altho Roseman presented the powersat, as it's sometimes called, 
as his own proposal, it has enough features shared by others that it 
is more of a general plan adaptable by almost any promotor of space-
based power plants. 
    My comments here summarize the situation, banking off of Roseman's 
talks. The ideas are not peculiar to him. Comments here are applicable 
to the project as a whole and not specificly the person offering it. 
    Now, as in the 1970s, the motivation to exploit space-based solar 
power was the potential depletion of fossil fuels, ecological and 
environmental degradation from burning the fuels, erratic price and 
political manipulation of fossil fuel. Solar power is free fuel, 
infinite in supply, and proofed against overseas interference, 
perfectly clean with no effluent or emission. 
    In the 1970s we had the interruption of oil supply by Iran, bitter 
winters that froze coal supply, new environmental regulation, steep 
(for the time) increases in crude oil price, manipulation of Caspian 
Sea oil by the Soviet Union. Today we have similar ills, with a new 
roster of players. 
    On the other hand, the growth in electric demand is moderated 
since the 1970s due to sustainability, greener lifestyle, recycling, 
more efficient machines and devices, shift to electronic from 
mechanical products. So the rapid growth of the 1970s slowed 
substantially, reducing the need for more generating plants. 
    New facilities are definitely needed and are being built, but by 
ordinary industrial procedures not obvious to the utility customer. 
There are no booklets in the bills proclaiming the next new power 
plant down the road. New projects tend to far smaller than formerly, 
a few hundred megawatts each, and placed on small lands of a few 
acres. This growth in supply seems to satisfy the future electric 
needs for the midterm future without having to appeal to space-based 
energy sources. 
DOE-NASA study 
    In the late 1970s I worked, thru my office, on one such study run 
by NASA and the newly formed DOE. The idea was to assess the 
feasibility of supplying a major portion of electric for a large 
market area in the US by a space solar power satellite. 
    My work was mostly on the handling of the microwave beam when it 
reached Earth, but my office had to coordinate with other units in 
scoping out the entire power system from orbit to customer. 
    The idea was to field a huge arena of photovoltaic cells in a 
geostationary orbit. The electric produced by the cells would be 
turned into a beam of microwaves. The microwave would be aimed at a 
station on Earth that turns it back to electric. Suitable equipment at 
this station fixes up the current to feed into the surrounding power 
    While this sounds like a repeat of what I said in 'Introduction' 
the basic plan hasn't changed much at all in the intervening 40 years. 
Only some details advanced and, believe ir not, we may soon end up 
with a space capability that reverts BACK to the 1960s! 
    My office assumed that some how the development and design and 
proving of the power station was carried by funding other than from 
the electric power industry. 
    At that time the industry was occupied with a sharp growth in 
demand and massive expenditures for new traditional power plants. At 
that time these included large coal and nuclear stations. 
    Thus, the industry would not be willing to try an experiment, 
which may or may not work, when it needed more power facilities within 
a couple years. 
    An other situation then, and possibly to repeat now, was the 
severe tightness of funding. Interest rates for loans and bonds was in 
the tens of percent and the debt payments consumed a large portion of 
the industry's current revenue. There plain wasn't spare change around 
to allocate to a new form of electric in space. 
Cell area
    In the 1970s a solar cell of production and spaceworthy quality 
yielded about 100 watt/meter2, or about 8% efficacy. Incident solar 
power at Earth distance from the Sun is about 1,400 watt/meter2. This 
is the absolute maximum electric an ideal conversion process can 
yield. There just ain't no more sunlight to squeeze energy out of. 
    To generate a given power in watts, the required area is the power 
divided by efficacy. For 100Kw, about the demand of ISS, from cells of 
200w/m2 yield, you need (100,000w)/(200w/m2)=(500m2). This is about 
the area of a room 22-1/2 meter square. 
    However, this power is that at the cell. There are losses, which 
in current space arts and skills are about 30% between the cell output 
terminals and the wall sockets. We need more like 650m2 of cell area 
to supply ISS. That's a floor about 25-1/2 meter square. This is, in 
fact, about the cell area of ISS. The panels are much larger due to 
structure and spacing between the cells. 
    Power efficacy of solar cells is improving. So far and in the near 
future, there will likely be no space-worthy cells better than 300w/m2 
yield. In lab experiments, yields of 400 to 500w/m2 are reported. 
These are in rigs totally unsuited for making real solar cells. 
    Many space advocates insist that such large yields are for cells 
that are now at sale in the likes of Radio Shack. They can be affixed 
to panels and sent into space tomorrow. 
    Solar cells to generate a reliable supply of electric must be 
faced toward the Sun. ISS is bodily rotated to face its panels toward 
the Sun. This is why there's so wide a range of brilliance of ISS when 
it passes thru your sky. The panels if tilted edgeon to you make the 
station much dimmer than if they are faced toward you. 
    What good are solar cells aiming down to the ground? ISS has cells 
on both sides of its panels to lessen the maneuvering it has to do. 
When one side faces you, the other is aiming up toward the Sun. 
    Most of the mass and bulk of the ISS panels is in the framework, 
hardware, and wiring. For a power station with its immense panels, 
this mass would be fabulously large. The frame must be extra strong to 
withstand torque, inertial reaction, flexure and torsion, and momentum 
transfer, solar pressure, magnetic stress, even tidal gravity from the 
    All in all, the area of the panel, with its cells and frames, is 
about twice that of the cells alone. 
Powersat area 
    Because of the fabulous expense and effort to place any large body 
in geostationary orbit, you want that powersat to produce a massive 
amount of energy to recover costs. You also want large output to 
displace Earth-based power plants that for one reason or other are not 
so desirable to operate. 
    All plans for powersats propose huge outputs in the multigigawatt 
range. A typical scenario is a 10Gw satellite, but it is sometimes not 
clear if this is the collected power in orbit or that ultimately 
reaching the ground. In the DOE-NASA study my office allowed 10Gw 
reaching the ground, regardless of what is collected in orbit. 
    There will be losses along the way from the electric in orbit and 
that on the ground, which my office took to be 50 percent. That was 
based on the ability then to convert to and from microwaves and 
absorption in the air. The powersat would have to produce 20Gw on 
orbit, which calls for a cell area of some 67,000,000m2, 67Km2! This 
is about about twice the area of Manhattan!! The optimistic 300w/m2 
efficacy and 30% conversion in orbit is assumed. 
    When the frame is factored in, we got a panel size, not just 
cells, of some 130Km2. If this sounds ridiculous, there are dreamy 
plans out there purposely showing such immense structures, all with 
teeny astronauts flitting around them. Some folk are walking around 
who don't blink at such figures. 
    Roseman emphasized the construction methods, using low Earth orbit 
to assemble the powersat modules and boost them to geostationary orbit 
for final assembly. He made heavy use of reusable fuel tanks as 
fuselages of the fabrication base. Astronauts live and work in this 
base and the operations in the higher orbit are done by remote control 
or automatonicly. 
    The idea is to keep the people within reach of Earth in case of 
trouble, like the concerns for the Shuttle flights. The powersat would 
be uncrewed. The modules would be such that they could be docked and 
attached without humans on the spot. Then, somehow, never explained by 
spacefarers, the powersat would be placed into commercial service. 
    In the 1970s there was no spacecraft that could be a model for 
building the space solar power satellite. Skylab and Salyut were the 
only large craft in orbit and these were sent up in completed form. 
Only trivial unfurling, extending, aiming, and so on were needed to 
put the craft into operation. 
    It is not at all clear from Roseman or others how large a 
workforce is needed to build the solar station. Assuming they stay in 
the low-orbit base, a ten-year program could mean 20 to 30 changes of 
crew, each having several dozen people. That's a lot of Shuttle or 
Soyuz or Orion flights. 
Human crew 
    In the 1970s scenario we assumed a crewed powersat because there 
was no fully operational means of running the station entirely on its 
own. in any case we felt a crew had to be on hand to look after the 
machinery and catch trouble before it gets out of hand. 
    For that study we had to estimate the cost of crewing the 
satellite. There was no comparable facility on Earth to judge the 
operating costs so we combined two extremely specialized facilities on 
Earth. We took the costs of crewing a nuclear power plant and a 
submarine for their complexity, confined quarters, isolation, stress, 
machinery to look after, training requirement. We assumed that 
specific space-related training,to be an astronaut, was covered by 
NASA and the electric industry covered the utility-related aspects of 
the crew. 
Space operations 
    The Shuttle was not yet in service for the NASA-DOE report, but 
still an unproven design. The only large rocket for lifting heavy 
payloads to low Earth orbit or moving them to geostationary orbit was 
the Saturn-V system. We configured the Saturn-V and Apollo capsules to 
ferry humans and materials to the fabrication base with dozens of 
    Roseman showed sealed pods at the ends of a rotating column to 
generate gravity by centrifugal force. He, like just about all other 
space fans, completely disregarded Coriolis force. The column and pods 
are made from spent fuel tanks of previous launches to the base. 
    In the DOE-NASA study we put in a low-orbit station like that 
showed by Roseman. It was a dedicated structure, a rebuilt extra 
Saturn fuselage, like Skylab. It would be the upper stage that enters 
orbit and is occupied by the crew from a later flight. Transfer of 
humans from capsule to base was by spacewalk. Materials went over by 
hauling them to tiedowns outside the base. 
    Spacewalks would bring the pieces together and couple them into 
the large modules for the move to high orbit. The base was merely the 
living quarters for the crew. All work was done outside where it was 
possible to configure pieces larger than the base itself and than fit 
them onto the upper Saturn stage for the trip upstairs. . 
    Nothing would be manufactured or made from scratch in orbit. There 
was and still is now no means to do that. The fabrication base would 
assemble the small items into larger ones and fit them with means for 
hooking them up via remote control. 
    We put humans on the power satellite for the sheer necessity of 
running the station and looking after it. There was no way we would 
allow such a huge project sit unattended. Far too many things can and 
will go wrong. Crews would be exchanged by upper stage Saturn and an 
Apollo capsule from time to time, but I can't recall the term of duty 
we proposed. 
    Roseman has the power plant running automaticly with remote 
supervision. All humans stay at the lower base. His heavy lift vehicle 
is the Ares-Orion system. However, this system is not intended for any 
construction work. They are stricta mente for ferrying to and from 
terminals like ISS. 
    It would be an immense project in itself to add extra function to 
the Ares-Orion to allow construction with them. This is in the face of 
recent NASA cutback in the Orion design. it may now carry only 4 crew, 
not 6. It may have far less propulsion so it has to wait at the Moon 
for a favorable gravity gradient to return to Earth, not come back on 
    It is noteworthy that neither then nor now is the Shuttle 
employed! The first study preceded the Shuttle, A future one comes 
after Shuttle flights terminate. 
    It is also noteworthy that after the Shuttle is grounded, there is 
NO means of construction planned by ANY nation. The Orion-Ares system 
is only for carrying humans and supplies like a car. The lunar habitat 
will be buttoned up on Earth, sent to the Moon via Ares rocket, and 
landed there in one piece. Only trivial fitting is done on the Moon 
like running a waste hose out from the base or plugging extension 
cords to power instruments placed away from the base. 
    Hence, any project calling for actual construction in space is 
doomed to die simply because there will be no construction services or 
facilities around in the midterm future. 
    Construction of the pwwersat would be enormously expensive, no 
matter what spacefarers say. ISS cost some $100 billion dollars -- as 
at November 2008 -- and took some ten years to complete. It involved 
about 20 Shuttle flights, many crew changes, and scores of supply 
Progress flights. ISS has a crew of three, maybe six when completed, 
and no real function other than keeping the crew alive. 
    The space solar power station, orders larger and higher and 
massive, would cost correspondingly more than ISS. Realistic 
estimates, suing reasonably expected space skills and methods, are in 
the trillions of dollars. Unless some utterly unexpected new and cheap 
means of lifting from Earth, traveling and working in space, 
supporting humans in space comes along, there is no hope or dream of 
lowering this incredible cost. 
    Roseman and others theorize, with no backing, that launch costs 
will magicly decline to a myriad of dollars per kilogram. This could 
apply to a satellite tossed into low Earth orbit. It can not apply to 
human occupants who have to return to the ground alive and well. 
    There's a lot more than launch costs, which are often the lesser 
part of a mission's total price. Design, testing, proving, building 
components  costs plenty. Training crews for the fabrication base 
costs plenty. Inventing the robots to assemble the power station in 
high orbit costs plenty. 
    Many systems proposed for the power satellite don't exist now, not 
even in smaller form. They have to be invented, a very iffy occurrence 
to predict. If any one critical portion fails to mature in time to 
send up to the powersat, it doesn't go up. This is, in fact, the fate 
of many spaceprobes. The Mars Science Lab may be the next example. 
Many of whose parts aren't yet worked out. 
    The bottom line is that there just is no fiscal sense to move to a 
space-based electric generating facility. Only if we get really near 
the end of coal and petroleum supply will we consider a space based 
    But even then, why must it be in orbit? Can't it be on the Moon? 
It will rise and set daily with the Moon, but is that so terrible? We 
can collect the power during the visible hours and let other longitude 
belts take power when the Moon passes over them. In fact, this feature 
could attract international cooperation being that the Moon is visible 
from every country as she orbits the Earth.
Fuel tanks? 
    I discuss here just one design feature illustrated by Roseman. His 
plan employs spent fuel tanks as fuselages for the low-orbit station. 
These would come from the rockets bringing parts for the station into 
low-Earth orbit. The tanks would be assembled into a column and pods 
to make a rotating construct for artificial gravity. The column is 
only to transfer between pods and maybe store of materials and 
    The pods would be sealed, like the original tanks, with crew 
inside a closef environment. Roseman showed nothing of how this crew 
receives pieces for the power station and how they get the finished 
modules to their booster rockets. The pods in his pictures indeed 
looked, well, sealed. 
    Why the closed environment? Is it necessary, convenient, desirable 
for building a solar satellite? No one who advocates this scheme 
offers competent answers. The best is that such a habitat is typical of 
a futurist society in space. Is it? 
    Perhaps for a interplanetary flight, where there is no routine 
need to go outside, a closed capsule is the sensible method. But what 
about a craft meant to interact with materials coming up from Earth, 
worked on in orbit, then delivered to high orbit? 
    Isn't it just cheaper and easier to build the fabrication plant in 
sections on Earth, ferry them into low orbit, couple them up like a 
new ISS? Crew would freely enter and leave the plant as they need to 
to work on the power satellite's components. The plant reasonably must 
have handholds, tiedowns, hatches, vents, antennae, grippers, electric 
cables, navigation devices, alarm sensors, and lots more over its 
outer surface. These have to operated from both inside and outside the 
    A plant built into an empty fuel tank would have a smooth solid 
exterior of no use for doing construction work. If you postulate that 
while in space, holes and fittings and attachments will be made to the 
tank, you lose all hope of savings in keeping the tank. You might as 
well build the hull on Earth with all the proper penetrations. 
    An other question is that can the tank be built to accommodate its 
future use as a hull? It could be fitted with lugs, seats, brackets, 
rails, sockets, and the like, into which the guts of the fabrication 
plant will attach. 
    This is a needless complication that could compromise the tank's 
primary function of handling fuel. Interior panels to mate with a 
section of habitat later could induce turbulence and cavitation during 
fuel flow. 
    Is the fuel tank really empty? Hardly. Residual fuel, film or 
pockets of vapor, have to the purged. This is a dangerous chore on 
Earth, like cleaning abandoned gasoline tanks. Fuel can be highly 
poisonous and corrosive. Ordinary spacesuits can not survive the fumes 
or spills during an in-orbit cleanup. You must invent a new protective 
suit, with special tools and life support, just to clean out the tank. 
    If safe and clean methods can be figured out, they will surely be 
extremely hazardous, complex, slow, and costly. For what? Avoid the 
destructive reentry of a fuel tank? It seems that trying to make a 
space hardware do two utterly anatagonist functions will be far more 
costly and risky than to just have one function for each of two 
separate pieces. 
     A final issue. Roseman notes that recoverable fuel tanks will be 
a standard feature of future rockets, specificly to turn into habitats 
in orbit. What rocket? Neither Area, nor Arianne, nor any other rocket 
on the drawing boards features salvageable tanks for use in orbit.  
Orbital stability
    A geostationary orbit is claimed by many space advocates as a 
stable fixed spot in space. A satellite placed there is like in a 
peghole to stand still over the equator at a given longitude. This is 
an outdated notion from the 1950s when we did not yet chart out the 
gravity field around Earth. 
    The satellite will drift away from its home location from various 
tugs of gravity from Sun and Moon. It may suffer push from solar 
pressure and magnetic fields. That's why geostationary satellites have 
onboard jets to keep nudging it back to home. They are decommissioned 
not so much from breakdown but from running out of propellent to 
maintain their orbital state. 
    An other newer concern is the disposal of retired or dead 
geostationary objects. The general practice is to boost them to a much 
higher orbit where in time they will be pulled out of the Earth's 
domain to become solar moons. This is the graveyard belt about 60,000 
kilometers from Earth. Just how a retired powersat will be disposed of 
is quite unknown. It may have to be deliberately boosted into solar 
orbit so it spirals to death into the Sun. 
    The reason to move them at all is to vacant the longitude seats 
for new satellites. The geostationary belt, 42,000 kilometers from 
Earth, has crowded zones over longitudes requiring dense telcomms 
service, while over other longitudes there are few satellites. 
    The linear spacing in orbit per degree of longitude is about 730 
kilometers. If we allow a safety zone of 50 kilometers on each side of 
a satellite, each degree of longitude could contain up to 7 
satellites. The buffer helps avoid interference of signals between 
adjacent satellites and possible collision as the satellites wander 
from home. 
    Because the powersat would be so immense and so crucial for human 
life, the exclusion zone may be 200 kilometers on each side. So in its 
longitude slot only 3 other small satellites could fit. 
    Space proponents count on a power station lasting indefinitely or 
for ever. They claim the space hardware is durable as they point to 
examples like Voyager, Mars rovers, SOHO. 
    This is nonsense. Saellites can and do fail. When a spaceprobe 
does fail, there is usually no way to repair it. The singular 
exception is Hubble Space Telescope, which went thru several visits 
via Shuttle to replace broken instruments or install upgraded ones. 
    Even ISS is essentially a frozen craft in orbit. Small items are 
brought up by Shuttle or Progress, but nothing in the order of 
replacing a structural section can be done to it. 
    Like any other spaceprobe, the space solar power satellite is 
subject to the unforgiving space climate. Metals weaken, plastics get 
brittle, glass crazes. Mechanical damage comes from meteors and (since 
October 2008) asteroids. Sputtering and spalling will destroy the 
solar cells. Motors burn out, switches stick, wires snap, springs 
loosen, transformers split, electronics overheat, sensors and trackers 
go astray, chips get zapped, and more. 
    With no means in geostationary orbit to send a repair visit, the 
powersat has to be curtailed in operations. Certain solar panels are 
shut off, for example. In time the power sent to Earth declines in 
sudden steps until there is too little to earn the keep of the 
    At the same time, the lost space-based power has to be made up 
with conventional sources on Earth. More nuclear plants may be called 
for. Eventually, the cost and effort to run the powersat's ground 
station is on longer acceptable and it, too, must be retired. To close 
out the powersat, it must be deliberately shut down, then moved to the 
graveyard orbit or spiked into the Sun. Then the ground station is 
demolished and its land freed for other development. 
    How long will this be after commissioning the satellite? The 
design lifespan has to be several decades, like most other large 
ground power plants. That's for the initial equipage, without 
continual replacement over its lifespan. 
     A ground power station undergoes continual maintenance and repair 
over its many-decade life. By the time it is retired, sometimes 
because there are newer alternative sources of electric rather than 
actual disfunction, there may be few of its original components in it. 
    There is no prospect of repairs or replacement in a powersat in 
geostationary orbit. Its lifespan is a minimum one, that of the first 
major system to break down. 
    Electromagnetic radiation conveys energy from its transmitter to 
its receiver. That's how a radio or remote control works, a feature 
first exploited by Tesla in the 1890s. 
    The choice of the microwave band is dictated by the properties of 
the Earth's atmosphere. From radio astronomy and planetary radar, this 
band penetrates the air better than many others. It is more tolerant 
of cloud, humidity, dust to reach the ground with enough energy 
density to yield useful amounts of electric. 
    The specific frequency, from a centimeter to submillimeter, is 
dictated also by the assignment of wavebands by the US FCC to other 
functions. If the beam lands near a radio astronomy center, there 
could be intense interference with observations, a form of radio 
    The only other significant alternative waveband proposed was the 
optical band. Here the energy would be carried by laser beams. The 
advantage is that the orders shorter wavelength allows for a tighter 
focus on the ground, requiring a smaller area for the receiver. This 
is no longer seriously considered for the gross hazard from a wayward 
beam. 10Gw poured over a single square kilometer outside the receiver 
campus is not a good thing. That's 10Kw/m2, an incinerator ray. 
    Political and social reaction against a laser-based power system 
would be vitriolicly negative. Check out the warnings on DVD players 
and lecture pointers, and ask supermarket workers about the laser in 
the paypoint scanners. 
    A one kilowatt laser is under test as a shoulder-mount gun to 
knock down planes and cruise missiles. Now here comes a laser beam 
fully ten million times stronger to a cornfield near you. 
    Microwaves are not without their own hazards. Microwave ovens have 
metallized windows to shield the operator from leaks. Cell phones and 
other wireless devices have warnings about long close position of the 
device near the brain.
    Microwave guns are under design for cooking the brains of enemy 
soldiers. Casualties will be cleaner and neater. Enemy structures and 
facilities will be safer to capture and occupy. 
    The column of dense radiation must have a no-fly zone around it. 
Planes would be excluded from it and surrounds, much as they are 
steered away from so many other no-fly sectors around the country. 
Apart from the nuisance of adding yet an other such sector, I see no 
special obstacle to air traffic. 
Reception at Earth
    My office allowed that somehow the power from the power satellite 
is placed onto a microwave beam and now I had to deal with it when it 
gets to the ground. The initial problem was that 10Gw then, and now, 
is a monster amount of power to put into the utility grid at one spot, 
like 10 typical nuclear plants on one campus. 
    There just weren't any such concentration of generation in the US 
except for possibly the Hoover or Bonneville projects out west. In the 
east, the largest in the 1970s were 2 to 3Gw projects, like Niagara 
Falls and Ravenswood. Both require massive collateral works to get the 
power from them to the electric grid. 
    Niagara Falls does this by many 345Kv transmission lines in both 
US and Canada (it's a joint operation) that was built as an integral 
part of the project. Ravenswood has a similar set of 345Kv lines, all 
underground, threading thruout Manhattan. 
    The cost of these works must be part of the overall project cost. 
In fact, for hydroelectric projects, my office requires that such 
power lines be incorporated in the project licence. 
    However, space advocates blithely ignore this part of the powersat 
proposal, thinking that the electric can be dumped into the existing 
network with no extra facilities to capture it. It can not. 
    Once the power leaves the powersat, spacefarers let it alone. 
Their illustrations show a pencil beam touching Earth at a point, 
which magicly becomes the electric to run your television, air 
condition, computer. 
    Air condition in homes and offices were rapidly becoming popular 
in the 1970s. So great was the increase in air condition that it 
shifted some utility peak load from winter to summer. Both NYS and PJM 
turned into summer peaking regions in the 1970s. 
    NYS is the New York State power region inclusing Con Edison. PJM 
is the Pennsylvania-Jersey-Maryland power region. Each operates as a 
unified electric system and coordinates electric flow between them and 
with other power regions. 
    That beam, filled with 10 gigawatts of power, has to land at some 
particular location. For my market of NYS-PJM, the likely location of 
the receiving station would be central within that region. 
    Now here's a fact no spacefarer likes to talk about. How big is 
this thing? It turns out to be humongous! For starts, the beam does 
feather out and wander as it comes down from the powersat, The antenna 
area must be large enough to capture all of it, else somw of the 
incoming power is spilled and lost. For safety and health reasons the 
beam has to be diffuse, of the order of incoming sunlight, or about 
1Kw/m2. For the 10Gw in this model, that is an area of 10Km2 or about 
3-1/2Km diameter. This is all of Lower Manhattan below Canal Street. 
    Allowing a 500-m buffer for wander and to minimize accidental 
trespass by people or animal, the campus for the receiving station 
would be about 16Km2 area. That's Manhattan south of Houston Street 
    It wasn't then and still is not today easy to find such a large 
available land for a single large-scale project. If anything, it's a 
lot harder today with the enhanced public participation in siting 
procedures and evolution of environmental awareness.
    Ideally the receiver should be located away from significant 
population and anticipated new development. The experience in hand 
from airports and industrial works is worth reviewing. Once in remote 
places, many of these facilities are now hemmed in by population growth 
and are now often regarded as nuisances and hazards. 
Locating the receiver 
    For the NYS-PJM market we found a potential place to site the 
receiver. There was and still is a thinly populated region along the 
NY-PA border with little industry or commerce. It is remote from jobs 
and towns and has poor farming or mining potential. It was, on the 
other hand, close to backbone transmission lines and there was room to 
add more lines. 
    So we placed, for study purposes, the receiver on the Pennsylvania 
side of the state border and added several output substations and a 
lots of 345Kv and 500Kv lines to reach to major nodes in the power 
network. New York had long ago settled on 345Kv for its backbone 
voltage while PJM chose 500Kv. Connection between the two then and now 
is via massive transformers and phase shifters. 
    As fate had it, many decades later this area would become the 
Cherry Springs State Forest, site of the Cherry Springs and Black 
Forest starparties! There NEVER was a serious plan to build this 
powerat ground station there, being that there NEVER was an actual 
project for the powersat. It was all a conceptual study on paper.
    The peripheral works would in themselfs substantial, several large 
switchyards, many transformer banks, forests of power lines. We had to 
choose the connection points within the grid to avoid overload and 
keep a balanced loading. We did flow simulations to see how the new 
power flux, in a north-south orientation, would disturb the normal 
east-west flow thru the NYS-PJM region. 
    It wasn't easy, but we did manage to get 10Hw into the grid for 
most of the time. In the peak hours and specially during seasonal 
diversity periods, we would have to spill space power because there ws 
no capacity in the grid to take it all. 
    Note well that scoping out a power system is a hell of a lot more 
than adding up the capacity of power plants. You have to examine the 
power flow over the grid. There are times when the flow on a given 
transmission line must be limited to prevent overheating or 
instability or reserve problems. A line working the satellite ground 
station is no different. 
    In the 1970s almost all electric transmission was via alternating 
current. Direct current power lines were uncommon with few under 
proposal for the future. It was simply cheaper and easier to move 
electric in AC form, particularly thru transformers. On the other 
hand, AC was more sensitive to geophysical disruptions, had was 
already documented in the late 1960s in my office. the reason was 
vaguely appreciated because space-based monitoring of the Sun was 
still underdeveloped. 
    The output of the powersat is direct current, being a photovoltaic 
process. The beam of microwave would also be direct current, by the 
nature of the power conversion from the solar cells. Hence, the power 
at the ground is a stream of direct current, which off hand would have 
to be changed back to AC. 
    We had then little experience with DC/AC conversion on a large 
scale. The alternators available were for modest power levels, like in 
industrial or traction operations. Unless we installed massive numbers 
of alternators, it may be best to leave the power output in AC and do 
the conversion at the far receiving points thruout the NYS-PJM area. 
    For recognition sake, we postulated 800KV DC lines (+/-400KV) to 
several farther connection points, more to show that we were aware of 
the potential for DC transmission in the east, like that running on 
the west coast. Since the 1970s, several high voltage DC lines were 
built connecting Quebec with New England and New York State, all 
working quite well with no serious problems. They proved to withstand 
geophysical attacks better than similar voltage of AC lines and avoid 
any troubles from alternating currents in air or structures. 
Utility role 
    We postulated that the consortium of electric companies in the NYS 
and PJM areas would pool resources to pay for the construction and 
operation of the power satellite. There was in the 1970s an 
established practice of sharing costs of building and running ground 
power plants like Homer City, Seneca, Roseton, Keystone. So the legal 
and financial mechanisms would be in place. 
    The development costs to perfect the space-related phases of the 
project were picked up by NASA. It would also take care of the space-
related training and qualification of crew and the transport to and 
from the station. Utilities would pay for the work done by the crew on 
orbit and during the stay on the station. 
    Modern proposals assume a government ownership and operation, like 
a TVA or COE project, perhaps from realization that the costs are so 
immense that no aggregate of private companies can finance it. 
    One curious aspect of a modern plan is the presumption that 
utilities are chopping at the bit to get space-based electric. This is 
not at all the case. For starts, some advocates still refer to their 
legacy power company when suggesting partners in the project 
    In bygone years, a typical utility ran power planets and sold the 
electric to its customers. Con Edison in New York did that. It had 
plants all over the City and shares of plants elsewhere. It carried 
the output thruout the City on its power lines to the customers. 
    Since about 10 years ago, utilities are now devested. Each now 
either generates the electric or sells it to customers. It can no 
longer do both. Con Edison, for example, kept its customers and got 
rid of its generating stations. Some were retired for being too old. 
Others were sold to other utilities or to allnew power producers. 
    Your electric bill from Con Edison has two parts. One, the larger, 
is the cost of the electric bought from energy producers; the other, 
Con Edison's cost of shipping the energy to you. Only the latter 
portion is still under state regulation! The energy purchases are 
under free market costs. 
    This situation has curious anomalies. Florida Power & Light, in 
Florida, went to generating, having sold off its customers. It then 
bought up other generating plants around the country! My office now 
deals with Florida P&L for plants it runs in the state of Maine! 
    What happened is that there is no 'electric utility industry' in 
the traditional sense to take on a solar power satellite project, 
however much it may like to get its energy. There is, from the 
fragmentation of the generation part of the industry, no single 
company large enough to tackle such a project. A consortium is still 
needed but now it must be made from fiercely competing firms. 
    Roseman and others emphasize that the powersat is on duty at all 
hours, save for a brief period when its orbit passes thru the Earth's 
shadow twice a year. These periods are known in advance so other 
supply into the market can be arranged. Fortunately these blackout 
periods are near the equinoxes, when power load is at moderate, 
neither at the summer or winter peak levels. Thus, we could postulate 
that the powersat was then taken off line for maintenance. 
    Weather was a problem. Thick clouds, frequent over the market, 
would weaken the beam. The power output from the receiver would drop 
as much as several gigawatts. Because weather is unpredictable in any 
dependible manner, the power output would be a random fluctuation that 
resembled that of a fickle river for a hydroelectric plant. 
    In sunny days the output was stable and ample. The geostationary 
orbit allowed generation to continue at local night, with the powersat 
hovering in the high south sky as an amazingly brilliant star. 
    Rain or heavy humidity would soak up the beam, diverting energy 
from the receiver. The absorbed energy was feared to cause local 
disruptions in weather, which at the time could not be proved. it 
still can't, even with a far greater ability to model weather on 
    Today this is no laughing issue. Public concern over carbon 
dioxide emissions, radon sippage, nuclear waste disposal, asbestos and 
lead airborne particles, and more would force a detailed analysis of 
the effects of microwave heaming down on a ground base. For starts, it 
is plausible that the artificially warmed air above the station would 
form a permanent low-pressure core. 
    Snow, common in the market, was an issue. It soaked up energy to 
melt before reaching the ground. It was a real possibility that the 
lack of snow would louse up local water cycles. There was the prospect 
that a solar power satellite could lessen the power generation by 
nearby hydroelectric projects. 
    So, for the most part we could count at some good piece of 
generation for most of the time, much like that of a huge hydro 
station on an erratic river. We were wary about employing it for 
system or contract power 
Market for powersat 
    10Gw is a big chunk of electric, far more than can be used by one 
town or one state. In the 1970s New York City needed about 9GW to meet 
its peak summer demand for electric. At other times the load was much 
less, down to about 4Gw. If the satellite power was dedicated to the 
City, most of it would be spilled. Some could be offered as dump power 
to other utilities. This is not the way to utilize the output from a 
massively complex and expensive satellite. 
    An other issue was that it is insane from a reliability and 
integrity consideration to count on so large a portion of electric 
requirement on one source. Space solar power has to be supplemented by 
other, ground-based, sources in case of downtime or outage. A 
supplemental amount of capacity would be needed in several smaller 
plants to fill in for the satellite. 
    I had to widen the market area for the space power to all of New 
York State and all of the PJM system. 
    When planning a power system, the ideal scheme is to work the most 
efficient and largest plants continuously as much as practical. The 
older, smaller, less efficient plants are turned on and off to follow 
the rise and fall of electric demand. The most wasteful, most 
expensive plants are put on line for the peak demand periods, of a 
couple hours at most. 
    Un the NYS-PJM area, the stacking of generation was in the 1970s 
first the large hydro works at Niagara Falls, Massena, and Susquehanna 
River. Then the nuclear stations at, as examples, Peach Bottom and 
Salem, Then come the large coal plants like Conemaugh, Keystone, and 
Homer City. 
    The load-following projects were the smaller coal and other fossil 
fuel units. To carry the highest demands, jet turbines and small hydro 
plants were added. Besides just the age, size, and economy of power 
plants, the sequence of adding them to the supply depends on their 
operating mode. A jet turbine can be started and put on line within a 
few minutes, but they are limited by their allowable running hours per 
week. They are built around ordinary airplane jet engines. 
    The dispatching of these plants thruout the region was coordinated 
by operating centers near Philadelphia PA for PJM and Albany NY for 
HYS. These centers also manage the purchase and sale of electric with 
other regions. It could for a given hour be cheaper or more effective 
to buy power than to turn on an other power plant. They must arrange 
for substitute supply when one of their own plants is off duty. 
    It was into this matrix the the 1970s study placed the power 
satellite. It would displace some, but hardly all, of the fossil-fuel 
power plants to cover the base load requirements. It could for the 
NYS-PJM region supply pumping for the storage plants like Muddy Run, 
Yards Creek, and Blenheim-Gilboa. 
    The situation today is similar, with a gradual increase in 
electric demand. The load on the grid is of a similar profile, with a 
rise and fall during the day and season. The important point to 
understand is that a 10Gw source, from any where, has to be placed in 
a very large market and not just for a town or small state. That 
requires major cooperation among the utilities in that region to build 
the ground facilities to allocate the power among them. 
    In spite of the promised purity of solar power, there are many 
environmental and ecological concerns, many unresolved as at now. 
There is little worry about the actual production of energy from the 
Sun, once the project is in service. 
    The problems come from the construction, which has all the burdens 
on the environment that a massive rocket activity offers. Hundreds of 
rocket flights are needed to build the base station and several per 
year there after to service it. 
    Rocket exhaust can be toxic and is concentrated in around the 
launch base. For the US this is Cape Kennedy, the other bases being 
too small for Ares rockets, or Saturn in the older work. Noise, water 
vapor, waste gases, partially-combusted fuel, jettisoned debris, 
shockwaves, and the potential for ground damage by falling pieces 
accompany each rocket launch.
    Leakage and spills of fuel and chemicals into local waters can 
upset ecology and degrade aesthetics. 
    Nighttime launches insult the sky with massive prolonged luminous 
graffiti for hundreds of kilometers around the launch pad. This is 
hardly mentioned by spacefarers or astronomers on the premise that it 
is predictable. Wait until the launch is over to resume stargazing. 
These folk know nothing about the scratchy schedule of rocket 
    Hazards come from the Earth-based industry to make the station 
parts and equipment and supplies. These are of the usual kind, of 
waste discharges, smoke and soot, spoiled land, noise, fumes, luminous 
graffiti, attraction to crime and nuisance, traffic congestion, 
political influence, social abuses. 
    Hence, a single space solar power satellite can insult humankind 
with the effect of the activity of a whole state or region of the 
country compressed n a ten-year span. The costs of remediation of 
these effects must be rolled into the price of the electric produced 
by the power station, For ground-based power plaets, such costs are a 
significant part of your electric bill.. 
    Will this all-in price compromise the validity of the project? No 
ne can tell. And no one is going to give the trillions of dollars to 
find out the hard way. 
Luminous graffiti 
    If the panels were as reflective as those on ISS, the powersat at 
times could appear as a, gulp!, -16 magnitude star, about 10 times 
brighter than the full Moon! 
    The 1970s were the nascent years of the ecological movement, so 
there was not yet a significant concern for 'light pollution' or loss 
of night darkness. Today there would be a mass agitation against 
putting something in the sky that stayed in one place and shined so 
brightly onto the ground.
    Arguments that it would aid in navigation at night (it's always 
fixed in the sky) just didn't fly. Nor did those that the illumination 
would facilitate farming and other chores normally closed at night. 
Perhaps it could eliminate the need for much ground-level lighting 
on streets or fields? No go. 
    As a target to inspect during stargazing, the powersat would be a 
sizable angular spot. At about 5Km diameter and 38,000Km slant range 
from the US northeast, the satellite would appear about 27 arcseconds 
across. That's about the size of a 50Km crater on the Moon. 
    Curiously, no astronomy interest, home or campus, and birtually no 
darksky advocate!, agitates against the solar power projecton for its 
luminous graffiti. I believe that's because there is no credible 
chance of it ever being built. 
Public safety 
    As part of our concern we had to consider the effects of the 
ground station on public safety. Already concern was rising among the 
public for safety in nuclear and hydroelectric plants. Longterm 
hazards were recognized from air pollution from coal and other fossil 
fuel-burning plants, plus disposal of the ash and slug from them. 
    What were the potential hazards from the intense microwave beam 
coming down from the sky? As long as people and animals were kept 
away, by a buffer region patrolled and fenced, there would be none. 
Workers at the station could be offsite beyond the buffer. 
    There was a problem with 'shutting down' the station for repair or 
maintenance. Like a nuclear plant, we can not turn off the prime 
power, the disintegration of atoms or the power beam from space. In 
such cases, we had to devise suits and vehicles that shielded workers 
against the beam when they had to enter the project campus. 
    This is quite different from a coal plant where it can physicly 
stop burning the fuel, cool off, and let workers enter its guts. They 
can ear ordinary industrial safety gear. 
    While the public can be excluded from the receiver campus, it may 
object vigorously to the sequester of a large piece of land from their 
use and enjoyment. They can not farm or graze on it, likely can not 
picnic, hike, do park recreation there. Roads would be relocated away 
from the campus, upsetting traffic circulation. Emotional effects 
could reduce property values, community attraction, industry/commerce 
    In the 1970s there were small, but harmful, attacks on utilities 
from environmental groups or individuals. They bombed power lines and 
substations thruout the country. My office cooperated with the FBI in 
dealing with these incidents. 
    It would be a stretch to total the receiver base, it being far too 
large and spread out for a single knock out blow. However, a 
switchyard or transformer could be taken out by a nogoodnik. This 
damage would weaken the service from the station, require rerouting of 
power, and call for costly tedious repair. It was also feasible to cut 
a transmission line far from the station by strapping a plastic bomb 
to one of the towers. The station would sense loss of one of its 
outlets and adjust its operations accordingly. One way would be to 
turn off certain receiver antannae to reduce the load on the remaining 
lines. Energy from space would then be spilled. 
    Of vastly greater concern, for which there was and still is no 
solution, it that the powersat in orbit is a sitting duck for any one 
who has it in for the United States. The 1970s was in the middle of 
the Cold War with the Soviet Union. 
    In the years before the Star Wars program of the 1980s, space 
attacks were deceptively crude. Just ramming a satellite would 
demolish it. Spraying paint on its solar panels would cripple it. 
Breaking pieces off with grippers and claws would maim a satellite. 
Lasers shot into its sensors or cameras would blind it. All these 
methods were actively tried, by actual experiment or simulation, by 
both US and USSR. 
    There was at the time utterly no way to ward off an attack upon 
the powersat, classed as a critical energy infrasturcture. There was 
no way to intercept the attack and probably no way to know of its 
approach. Suddenly there is no more power beam coming down to the 
ground and all comms with the satellite is lost. At night you see a 
flashing blinking star, the tumbling remains of the powersat. 
    There was no way in hell the US would expose a crucial energy 
facility to such an obvious security risk. A single small enemy 
rocket, costing a few million rubles, could in an instant throw the 
entire NYS-PJM region into a irrecoverable power blackout. 
    Today, the 20-thous, there still is no feasible way to protect a 
powersat. The threat now comes from several countries, not just the 
old USSR (Russia is going thru a nationalist fit). Think of Venezuela, 
Red China, North Korea, Iran, Pakistan, Libya, to name only a few of 
the larger ones. Lots of countries have or soon will have space access 
and military capability there: the Ukraine, Belarus, India, Japan, 
North Korea, Iran, Taiwan, South Africa, Nigeria, Israel, Germany, 
France, again naming a few. If any of them gets, or feels, crossed by 
the US, a powersat could be a tempting target to get even on. 
    If this assessment sounds like nonsense, as many spacefarers 
insist, you have only to look at Ground Zero. There, in the middle of 
the planetary capital, the World Trade Center was wasted with a 
thoroly low-tech weapon passing thru an indefendible airspace. 
Military involvement
    The space solar power satellite in all its forms is passionately 
presented as a pura mente civilian project to benefit humankind. It is 
proclaimed as a mission for civilian space agencies and industry. 
    Neither Roseman nor other proponents realize that just about any 
space project now and in the future has a heavy thumbprint of military 
potential in it. The utter disregard for this basic fact of life seems 
shocking, given the many current examples of space programs of 
civilian benefit that are in whole or part a military operation. 
    To give three simple, yet major, examples the Space Shuttle, 
Clementine, and GPS enjoyed massive support from military interests. 
All are touted as principal examples of civilian benefit from space 
    The powersat can hardly be any different. Besides its incredible 
cost and dangers, which only a military establishment would think to 
absorb, there is the utility of a geostationary base overlooking 
Earth. It is reasonable to suppose that the powersat will carry spy 
devices and command & control services for military use.
    If this sounds unlikely or undesirable, note well that right now 
the USAF is negotiating with commercial telcomms companies to put 
military functions in future satellites. It would pay for the extra 
soalr panel and chassis room to support spy equipment while the 
satellite carries out its civilian telcomms operations. In Europe the 
Galileo project is seeking a military partnership altho it started as 
an all-civilian works. 
International power
    Because the electric from the satellite has to be sent to a one 
particular place, within one country, there could be little chance to 
attract overseas cooperation in building or running the satellite. In 
fact, for the US, there are only a few places with international 
operation. The major overseas partners for such joint electric 
operations are Canada and Quebec on account of the long shared border 
between them and the US. There are as yet only minor joint facilities 
with Mexico. 
    The Niagara Falls and Massena projects straddle the US-Canada or 
US-Quebec border, so the works are jointly run by each pair of 
country. An other inducement for cooperation is that these plants are 
in the Great Lakes basin, controlled by the three countries thru the 
International Joint Commission on Great Lakes Regulation. 
    The ability to transfer bulk electric across oceans is today 
nonexistent. For distances of a hundred or so kilometers, it is 
ridiculously expensive.
    There is no significant work to develop overseas electric 
transmission at this time and none is planned for the near future. 
Hence, A solar power ground base on Malta to send its output to Italy, 
Libya, Egypt, Greece is just not possible. 
    Roseman offers that the low-orbit station could be platforms for 
training travelers for Moon and Mars flights by its artificial 
gravity. It just is easier and cheaper to build a specific satellite 
for this purpose that to tack it onto an industrial facility. 
    There is the security issue again. Consider the heightened worry 
about Russia's role in ISS since summer of 2008. Given what it did in 
Georgia and wants to do in Poland, the Baltics, and Caspian Sea, it is 
not out of order to think Russia will bar US astronauts from its Soyuz 
lifeboat on ISS or refuse shipping US supplies to there by its 
Progress ships. 
    Imagine the sword over the US if an overseas partner in the solar 
power station feels dissed? It could, litterally, throw a wrench into 
the gears and that's the end of electric service in the US east coast. 
What century?
    The first idea for a space electric plant arose in the 1960s, when 
oldstyle weights and measures were prevalent in the US. Starting in 
the late 1970s there's been a steady migration toward metrics. All the 
space agencies and companies went metric by the late 1980s. 
    It is a bit much to suppose that within a decade oldstyle will 
fade away. The reasonable accommodation is that Americans are bimodal, 
comfortable with both systems of units. 
    Yet Roseman, and far too many other space fans, cling to oldstyle. 
They exert too little effort to move into the future, along with their 
agenda. This is among the queerest features of space advocacy I see. 
    Astronomy went metric decades ago, with American home astronomers 
conversing fluently in either system. Home astronomers deal only in 
metrics with overseas associates, 
    Yet even in reputable spacefaring litterature there is a 
predominance of oldstyle, even for material aimed at global readers. 
The result is a ball & chain on the American spacefarer for global 
support, recognition, credibility. It also induces a giggle factor 
with dealing with governments who may want to take up one of their 
ideas. For sure, 
    Roseman's illustrations were adapted from other sources flecked 
with oldstyle measures. He could almost at sight alter the dimensions 
to metric before making the handouts, White out the old numbers and 
pen in the new. He didn't, thereby missing out an awfully basic step 
in building confidence in his audience. 
    Yes, in the early days of the US space program, the engineers and 
scientists worked mostly in oldstyle. I have a copy of the operating 
manual and script for the Apollo-11 flight with detailed instructions 
for the ride to and from the Moon and activity on the lunar ground. 
Everything is in oldstyle! That's how it was back then. 
    We be in the new millennium. If we be future-facing folk, we have 
no qualms about moving to metrics as quickly as practical. That does 
call for deliberate work. It's like being fluent in two languages, as 
in Belgium. 
    For my own space advocacy, and that for astronomy, I employ 
metrics exclusively. It's been litterally 25 years -- back in the days 
of Halley's comet! -- since anyone raised a serious substantial 
objection to metrics. Yes, some audience do ask how much so-many 
kilograms is. I give a physical example, it's about the mass of a 
certain object. I never give the oldstyle equivalent. 
    This does two things. First, it reminds that metrics are the 
essential ingredient of life in this century. Second, I subliminally 
give a lesson in visualizing a given metric quantity. 
    Since its conception in the 1960s, thru many studies since then, 
the allure of a solar power station in high orbit still attracts 
attention. The outcome so far is the same: It's not worth it. 
    Unless and until a genuine breakthru in several of spacefaring 
skills and arts come along, there will never be a single kilowatt 
produced in space to light you lamps at home. 
    Some space project promotors plead that there will be a way to get 
into space for ten dollars per kilogram or get 800 watts per square 
meter of solar cell. So they go and urge that the power station can 
and should be built now. 
    They also commonly dismiss all thought of contingency. Everything 
will work correctly and perfectly. Every launch will succede by plan. 
Every part will fit exactly by plan. The electric will flow for 
decades without serious interruption. People on Earth will have such 
abundant cheap power the utility can pull out its meters and let you 
take all the electric you want for a flat rate per month. 
    Need less to say, this plain will not happen. Just in New York, 
besides the World Trade Center, we had in the last ten years a major 
steam pipe eruption that eviscerated a midtown street, a GPS navigator 
that sent a car into Metro North tracks to be totaled by trains TWICE,  
a sinkhole near Union Square that swallowed several cars, helicopter 
crashes, ferry boat collision that killed a dozen people, airliner 
lose its tail on takeoff to crash in the Rockaways, airliner blow up 
off Long Island from a fuel leak, train wreck in New Jersey due to a 
color blind driver, a construction elevator rip away from a skyscraper 
in Times Square, and lots more. 
    If you're looking for calamities in space, consider just one week 
in November 2008. Globalstar telcomms company warned that 42 of its 50 
satellites are deteriorating so they will lose function in early 2009, 
crippling the firm's voice services. Orbcomm reported that 6 new 
satellites launched in June 2008 had defective attitude control 
systems, their reaction wheels not working properly. 
    In addition to actual catastrophes we got plenty of examples of 
things that didn't work at all. The robotrain on the BMT Canarsie line 
never worked after years of tinkering, GPS-powered bus displays gave 
wrong times and locations of buses, atomic power plant inside 
Morningside Park that never fired up, Second Avenue subway keeps 
getting dumbed down but never built. 
    All of these were part of machines and systems of long maturity 
and experience. Yet stuff happens.