REFERENCE TO RELATED APPLICATIONS

This is a continuation- in - part of application U.S. Pat. Ser. No. 527 , 284, filed May 5,

1994, which is a continuation of U.S. Pat. Ser. No. 238, 473, filed May 6, 1994, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of communications and more specifically to a

telecommunications platfo that is capable of being precisely positioned within the

troposphere or stratosphere for providing regional and global communications that is

economically and environmentally compatible.

2. Background of the Invention

The present invention, a system of high altitude lighter-than -air telecommunication

platforms, is specifically designed to provide an economical and environmentally compatible

system for effecting global and regional telecommunication. A Corona Ion Engine™, using

ambient air as fuel and solar radiation as power source, permits each communication platform

to be stationary and long-lasting at stratospheric heights. The high altitude reduces wind-drag

and allows a large foot-print to be covered. Laser communication between platforms is

possible because scattering is minimized as a result of the low atmospheric density. This

global communication system will complement the present global satellite communication network.

OBJECTIVES OF THE INVENTION

Technological advances in the field of communications and more particularly in the

field of satellite-based communications systems have allowed for great advancements in

regional and global communications. Today, satellites serve as the main vehicles for

achieving global telecommunication. Typically, they are launched into orbit by rockets or by

Space Shuttle and then either circle the globe or remain geo-stationary. Recent research has

revealed that exhausts from rockets have a damaging effect on the environment, such as on

the ozone layer. In addition, the short lifetime (three to five years) of orbiting satellites and

rockets means they will plunge into the atmosphere, generating space debris as layers of

metallic dust, which poses serious environmental problems.

The multi-billion dollar Iridium Project is a state-of-the-art example of this

technology. At its completion at the end of the Twentieth Century, seventy-seven satellites

will encircle the globe with telecommunication services. Each of these satellites will have to

be replaced periodically, because of fuel depletion or equipment failure.

Geosynchronous satellites must orbit far above the earth's equator (6.6 earth radii

away). The allowable number of satellites in synchronous orbits is limited and their great

distance from earth precludes direct control by small transmitters like cellular phones.

As the global demand for communication services increases, satellite development,

launching and maintenance will expend more and more resources. Economic and

environmental concerns, coupled with expensive cleanup of satellite debris, could severely

restrict future satellite launchings. When this comes to pass, it will no longer be feasible

exclusively to support a satellite-based, global telecommunication network. A need therefore

exists in the art for a less expensive and more environmentally compatible alternative method

for creating regional and global communications networks.

The stationary platform described in this patent serves as an alternate communication

network which can complement and supplement the existing satellite system. This alternate

telecommunication technology is cost-effective, environmentally sound and operates in the

stratosphere, 12-30 kilometers above the earth. This platform bears the trademark name of

Sky Station™. Sky Station™ represents an enormous economic advantage over satellite-

based communication services. It is estimated that leasing time on Sky Station™ will be one

percent the cost of current satellites because of the following major cost-saving features.

Sky Station™ does not require launching by expensive rockets or Space Shuttle. It

ascends to its operating station via its buoyancy and under its own power from a conventional

solar-powered engine and the Corona Ion Engines™.

Sky Station™ can lift tons of payload, whereas most satellites can only manage

hundreds of pounds. Thus Sky Stations™ can carry enough equipment for broadcasting over

a wide range of bandwidths and frequencies. This allows them to support the entire spectrum

of radio, television, cellular phone, microwave infrared and optical communications from a

single location for one or several states. This concept of a high-altitude relay station has

already proved to be successful and economically viable in many large cities.

Sky Stations™ can carry equipment for astronomical observations in the wavelength

range from ultraviolet to infrared because of their lifting capacity and because they operate

above 99 per cent of the atmosphere. These platforms are kept at precise locations, using the

Global Positioning Satellites (GPS) navigation system or alternately, ground-based,

triangulation stations.

Sky Stations™ require less transceiver power because they are so much closer to the

earth than geo-stationary satellites. Thus smaller batteries and antennas can be used and communication with conventional cellular phones can be direct rather than indirect, as

through a satellite dish. This capability means an entire region of a country could be one

"cell," thus eliminating the complex and costly multi-cellular phone grid that presently

blankets our urban centers. These unsightly cells are often unwelcomed by neighborhoods.

Every transmission in the area would go directly from the sender up to Sky Station™ and

directly back down to the receiver.

Sky Stations™ are more sustainable than satellites. Their modular design, fabricated

from modern composite materials, enables them to remain aloft for a minimum of five years

before requiring service. In the unlikely event they require intermediate servicing, they can

be brought down by special aircraft to a lower altitude for servicing. If this happens, another

Sky Station™ will be dispatched in advance so that communication will not be disrupted.

Satellites can only be serviced by expensive and difficult-to-schedule Space Shuttle missions.

Sky Stations™ are recyclable. If necessary, Sky Stations™ can be completely

refurbished by returning them to the launch site and landing them. Satellites are not

recyclable. Their orbits decay, plunging them back into the atmosphere where they burn up.

We can foresee a day when we will no longer be able to afford, either economically or

environmentally, a disposable global communication system.

Sky Stations™ are more flexible than orbiting satellites because these satellites

remain over a city only for a few minutes during each pass and therefore have to keep

relaying data to the next satellite. By contrast, because it is stationary and large enough to

maintain the necessary equipment, Sky Station™ always has the flexibility to retransmit

immediately, store and forward, or transmit to another Sky Station™.

The advance airship technology required to build The Sky Station™ platforms exists

today. One Sky Station™, approximately 200 meters long, with a total volume of 400,000

cubic meters, will be capable of lifting a two-ton pay load. That would provide ample

coverage for average-size cities and rural areas. Coverage depends on three major factors, the

altitude at which the Sky Station™ operates, the volume of transmissions it has to handle and

the terrain over which it operates. Therefore, the very largest and most densely populated

cites, such as Tokyo or Los Angeles, may require additional Sky Stations™ because of the extremely high volume of transmissions. Multiple Sky Stations™ would be inter-linked by

lasers to provide continuous coverage. This concept can be applied to cover vast regions like

Europe, Southeast Asia or the entire globe.

Urban dwellers will benefit from Sky Station™ because they will have disaster-

resistant, nearly unlimited communication capabilities, without a profusion of expensive and

unsightly towers. In January, 1995, many lives were lost in Kobe, Japan, because the

earthquake knocked out virtually all communications. Sky Station™ is not subject to

earthquakes or the weather. It can also facilitate numerous specialized applications, such as

medical and traffic monitoring.

People living in remote or underdeveloped areas will benefit from the "leapfrog" in

communication technology without having to go through the costly and time-consuming

progression from wires to fiber optics to satellites. With the launch of a single Sky Station™,

everyone in vast areas of Eastern Europe or Africa would immediately gain "state-of-the-art" communication systems.

One Sky Station™ can cover the entire country of Italy. Using a footprint of 1000

kilometers, one Sky Station™ would cover most of Italy, including major metropolitan areas.

Two stations might be employed for better coverage of the mountainous northern region,

duplicate coverage of Rome and the populous central region and coverage of the Adriatic Sea

and part of the Mediterranean Sea areas.

Therefore, it is an object of the present invention to provide an economical and

environmentally compatible telecommunication system for regional and global

communication.

It is yet another objective of the invention to provide for a system high altitude

telecommunications platforms that can be launched from the ground via flotation using

lighter-than-airships. This launch capability represents a considerable savings over Space

Shuttle launches.

It is yet another objective of the invention to provide for a telecommunication system

consisting of a series of reusable platforms that can be returned to earth for repair or updating

and then returned to operation. Whereas conventional satellites have a finite life and must be

retrieved by a Space Shuttle launch or they will fall back to earth, being destroyed in the

process.

It is another objective of the invention to provide for a series of high altitude

platforms that are capable of carrying large telecommunication payloads and which are

capable of remaining on position above a given region on the earth for prolonged periods of

time.

Finally, it is an objective of the invention to provide for a series of telecommunication

platforms, each of which is propelled and maintained in a geo-stationary orbit above a given

region of the earth by use of a Corona Ion Engine. A Corona Ion Engine utilizes ambient

atmosphere as its source of fuel and as such is not dependent on conventional fuel systems, as

satellites are.

SUMMARY OF THE INVENTION

Sky Station™, as shown in Figure 1, is a large-scale (approximately 200 meters long),

environmentally compatible (non-polluting either in terms of release of chemicals or energy),

durable (minimum of five years), reusable, airborne, lighter-than-air platform. It uses the

unique Corona Ion Engine™ to provide a stationary, high altitude ( 12-30 kilometers)

telecommunication platform over a predetermined site. Sky Station™ is capable of

broadcasting a wide range of frequencies with high bandwidths over a one-thousand

kilometer area. This includes the use of laser technology at the stratospheric level for long-

range, broad-band communication to other Sky Stations™ or satellites.

The large-scale, airborne platform utilized by this technology is only practical and

economically feasible when used with the Corona Ion Engine™. Sky Station™ is stationary

over a given region in order to provide easy access. Therefore, the Corona Ion Engine™ only

needs to counteract the minimal wind forces at that altitude; it needs not provide propulsion

and lift like aircraft engines. This ion propulsion system has significant advantages over

others for this application because it has no moving parts and utilizes solar power and

ambient atmosphere as its source of ions. Based on laboratory working prototypes, this

propulsion system without moving parts is ideal for operating at high altitudes, literally for years without maintenance.

Sky Station™ represents an opportunity to leapfrog current technology, such as fiber-optics

and cellular cells on the ground and satellite network in space, to provide a broad spectrum of

inexpensive, commercial telecommunication applications. This technology is expected to

have significant remote sensing and monitoring applications in both civilian and defense

arenas.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic view of a Sky Station telecommunication system of the present

invention.

Figure 2 is a schematic view of a stratosphere-based global communication system, using

large-scale platform structures.

Figure 3 is a schematic view of how laser and microwave beams establish communication

between two platforms.

Figure 4 is a side view of an ion engine for use with an embodiment of the system of the

present invention.

Figure 5 is a block diagram showing the structural and functional operation of an embodiment

of the electrical system of the present invention.

Fig. 6 is a schematic view of an embodiment of a telecommunication platform for use at

altitudes up to and including the stratosphere.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will be made in detail to the present preferred embodiments of the invention,

examples of which are illustrated in the accompanying drawings, wherein like reference

numerals indicate like elements through the serval views.

FIG. 6 depicts a portion of a preferred embodiment of a global high altitude

telecommunication network known as the Sky Station GSTS system. This preferred

embodiment of the invention consists of a network of 250 Sky Stations 10, several thousand

ground stations 85 which operate as control and switching centers, and many millions of

small, inexpensive, portable and mobile Stratus Communicators 87. This preferred

embodiment of the Sky Station systems operates autonomously, but also fully interconnects

with the Public Switched Telephone Network (PSTN) 86. A preferred embodiment supports

communications using the 47-50 GHz frequency band.

A. Geometry of a Preferred Sky Station Embodiment

In a preferred embodiment of the invention, depicted in FIG.6, the Sky Station system

provides service capabilities which are intermediate between those of terrestrial and satellite

systems. Terrestrial wireless communications systems provide low angle of elevation

coverage in urban areas and little or no coverage of the surrounding countryside. Satellite-

cellular systems provide high angle of elevation coverage to both urban and rural areas, but at

the expense of reduced capacity to any one area and high cost to all areas. In the preferred

embodiment depicted in FIG.6, the invention provides high elevation angle service to

metropolitan areas and low elevation angle service elsewhere, both at very low cost and with

large capacity. The key to understanding the capabilities of this preferred embodiment of the invention begins with this embodiment's geometry.

In the preferred embodiment depicted in FIG. 6, a Sky station 10 is located approximately 30

kilometers (18 miles) above the geographic location which acts as the center of maximum

population density for a coverage region. In other preferred embodiments, the Sky Station 10

may be located at other altitudes in the stratosphere or troposphere. From an altitude of 30

Kilometers, the Sky Station 10 communications payload defines coverage areas on the

surface of the earth, referred to as cells 84, as is well known in the art. Directly below the

Sky Station 10, the coverage area will consist of cells 84 with a one mile radius (3.14 square

miles). As one moves away from the zenith, the cell sizes expand. At a distance of

approximately 50 kilometers from the zenith location (approximately 31 miles along the

surface of the earth), the Sky Station 10 will be at a position in the sky approximately 30

degrees above the horizon. At this radial distance, which includes approximately 3,019

square miles, the cell radius will now be approximately 4.05 miles with a corresponding

coverage area of approximately 51.5 square miles. As one extends further form the zenith

point to the horizon, the elevation angle for communication continues to decrease and hence

the cell size continues to increase.

The result is that where population densities are high and transmission path obstacles are

ubiquitous, such as metropolitan areas, this preferred embodiment offers both small cell sizes

with resulting increased capacity and high elevation angles. Where population densities are

low and building less frequent, such as rural areas, this preferred embodiment offers large cell

sizes with less capacity and lower elevation angles. These fundamental geometric

considerations ultimately explain the tremendous cost effectiveness of this preferred

embodiment of the invention.

In other preferred embodiments, not depicted in FIG. 6, one ore more Sky Stations may be

positioned over any geographic region to meet local or regional communication requirements.

FIG.2 depicts a preferred embodiment of a network of Sky Stations lOproviding global

telecommunication capability. In this embodiment, a series of Sky Stations 10, in a geodesic

domelike arrangement, encircles the earth 20 Corona Ion Engines not depicted in FIG.2,

propel each individual Sky Station into position at proper stratospheric heights.

FIG.3 depicts a preferred embodiment in which Sky Stations 10 communicate with each other

by high-frequency electromagnetic waves (microwaves (not depicted in FIG.3) and lasers 31

extending to the UV wavelength range), thus allowing the greatest bandwidth for

communication. Lasers 31 are not efficient or even possible at lower atmospheric heights

because the atmosphere interferes with signal propagation by absorbing and scatting laser

radiation. UV lasers cannot be used at lower heights because the ozone layer absorbs the

signals. This preferred embodiment, with lasers 31, offers an alternative to the expensive,

ground-based network of fiber optics, microwave or radio cellular systems.

An alternate preferred embodiment employs a Sky Station propelled by ion engines at

stratospheric heights for astronomic observation requiring minimum interference from the

atmosphere along the line-of-sight.

A. preferred embodiment of a method for establishing a telecommunications platform for use

at altitude up to and including the stratosphere includes the steps of launching one or more

telecommunications platforms, maneuvering the platform or platforms into position at

altitudes up to and including the stratosphere, and providing telecommunications services

through the use of the platforms.

B. Technical Description of a Preferred Sky Station Embodiment In a preferred embodiment

depicted in FIG. 1, a Sky Station 10 is a large-scale (650 feet long) environmentally

compatible (non-polluting either in terms of release of chemicals or energy), durable,

reusable, lighter-than-air platform. In this preferred embodiment, Sky Station 10 uses Corona

Ion Engineers 20 to provide stationary, stratospheric telecommunications services over a wide

area.

There are a large number of alternate preferred embodiments for large-scale Sky Station. FIG

1 shows a preferred embodiment of a Sky Station 10 of the present invention, which is

suitable for use up to and including the stratosphere for carrying telecommunication systems,

and for transponding signals from one point to another, form earth to Sky Station 10, from

Sky Station 10 to satellites and from Sky Station 10 down to earth. This preferred

embodiment of Sky Station 10 includes a set of ganged helium airships 12. Each helium

airship may be generally conventional, made of lightweight, metal framing and fabric and

inflated with helium gas. In alternate preferred embodiments, other lighter than-air gases,

such as hydrogen, may be employed. Each airship 1 in the preferred embodiment shown in

FIG. 1 is approximately 200 meters long and 30 meters in diameter at the maximum inflation

point. These dimensions may vary considerably in alternate preferred embodiments.

Although two ganged helium airships 12 are shown in FIG.1 , altemate preferred

embodiments may employ a variety of airship types and configurations. For example, while

oblong helium airships 12 are shown, spherical helium balloons or other lighter-than-air

airships can also be used.

In the preferred embodiment depicted in FIG. 1, the airships 12 are joined together by a

horizontal plank structure 13, which supports the solar panels 14 required for primary power.

In the preferred embodiment depicted in FIG. 1, this structure 13 also supports downward-

looking microwave or radio frequency antennas 15 and 16. Horizontal antennas 17 provide

communications with other Sky Station 10. Upward-looking antennas 18 allow

communication with satellites above and also allow astronomic observations in frequencies

ranging from radio, through microwave, to laser in the infrared, optical and ultraviolet

regimes. These upward-pointing antennas 18 also allow the use of Global Position Satellites

(GPS) for navigation and precision positioning. The Sky Station 10. A laser port 19 allows

laser light to be emitted to other Sky Stations 10 for optical communication Ion engines 20

are mounted at the end of each airship and serve to navigate and to keep the Sky Station 10

stationary.

FIG.5 depicts a functional block diagram of a preferred embodiment of the electrical system

of the invention. The bank of solar panels 14 provide Dc electric power for the system. The

power may be temporarily stored by storage batteries 62 or fuel cells (not depicted in FIG. 5).

The DC power from solar panels 14 is converted to AC power by inverter 64. Transformer

66 converts AC power to the desired voltage levels for driving propeller motors 68, which

may be used for tropospheric navigation. AC power is rectified by rectifier 72 to vield DC

power, which provides a negative voltage for electrodes 73 in an ion engine. Computer

controller 76 operates the system. In a preferred embodiment, the computer controller 76

uses software such as Labview to determine which ion engine electrodes 73 should be "fired"

or connected to the negative high voltage, thus determining the momentum and torque

provided by the iron engine. Computer controller 76 receives GPS navigation signals and

uses this information to move Sky Station to a specific location or to remain stationary.

Because of the desirability, in some preferred embodiments, of maintaining a Sky Station in

the stratosphere over a long period of time, the Sky Station may be unmanned and all their

functions controlled the computer controller 76 or remotely from the ground.

C. Component Descriptions of a Preferred Embodiment

1. Mechanical Systems. The weight and buoyancy of a preferred embodiment of the

invention, depicted in FIG. 1, is as following:

Total buoyant gas volume 800,000 m3

Total buoyancy 37 tons

Envelope and Duct Weight 11.7 tons

Fuel Cells 10.53 tons

Solar Cells 2.07 tons

Power Cables & Wiring 0.50 tons

Main Engines 1.00 tons

Propellers & Gears 2.00 tons

Communications Payload 2.80 tons

Control Equipment 0.60 tons

Empennage 4.40 tons

Reinforcement 1.40 tons

Total Weight 37.00 tons

2. Power Systems. In the preferred embodiment depicted in FIG. 1 , the Sky Station

10 uses solar power, battery power and ion power. Each of these three sub-systems is

discussed in more detail below.

A. Solar Power. In this preferred embodiment, the Sky Station horizontal plank

structure 13 includes a broad flat platform that is substantially covered with high efficiency

solar panels 14. These solar panels 14, in this preferred embodiment, generate one megawatt

of power, most of which is used to power the primary communication payload. Provision is

made for a 50% degradation of solar panel output over time, resulting in 500 kilowatts of end

of life power. Reserving 20 kilowatts of power for stationkeeping, battery charge and margin

(i.e., Corona Ion Engines 20), and using a DC-RF conversion efficiency of 33 %, there will

be 160 kilowatts of RF power available at end of solar panel life.

B. Battery Power. In this preferred embodiment, fuel cells, not depicted in FIG. 1 ,

are used for battery power when the Sky Station 10 is in darkness. There is no issue of cloud

cover because the stratosphere is above all clouds, However at night and during solar

eclipses, solar electric power must be supplemented. Correspondingly, in this preferred

embodiment, nearly 30% of the weight of each Sky Station 10 consists of fuel cells, and these

fuel cells generate approximately 150 kilowatts of power at night. After reserving 20

kilowatts for other needs, this is approximately 80% of the daytime power generated by the

solar panels 14 and is compatible with the reduced communications load expected at night.

In alternate embodiments, chemical batteries or other means for storing electrical power

known to the art may be used.

C. Ion Power. In this preferred embodiment, as depicted in FIG.l, Sky Station 10 uses ion

power for propulsion, relying on the plentiful flux of ions available in the stratosphere. In the

troposphere conventional propellers, not depicted in FIG. 1, can drive Sky Station 10.

However, the thin atmosphere of the stratosphere renders propellers inefficient. Hence, a new

propulsion system, the Corona Ion Engine 20, was invented for use at all altitudes. These

engines can be used with and without conventional propellers. In this preferred embodiment

the ion engine is solar-powered and uses the surrounding atmosphere as its source of gas.

The Corona Ion Engine 20, a preferred embodiment of which is depicted in FIG. 4, includes

emitter electrode assemblies 47, each of which comprises a plurality of pointed electrodes.

The electrodes are biased, in this preferred embodiment, at a negative voltage in the range of -

1 to 25 kilovolts, depending on the ambient atmospheric pressures, to create a strong electric

field at the tip, which serves to eject energetic electrons into the surrounding atmosphere.

The population of charges in a gas stream can be increased by radiating a gas with focused

solar (UV) radiation as shown in FIG. 3. Such radiation of short wavelength has the energy

to ionize molecules into charged ions.

A positive electrode, not depicted in FIG.4, is positioned in the vicinity (1 -5 cm distance) of

the emitting electrode assemblies 47 to complete the circuit as a result there is no build-up of

charges on the engine. Allowing it to sustain continuous operation. The emitted electrons are

accelerated by the surrounding electric field, forming a plasma of electrons, negative ions and

positive ions, by the process of ionization and charge attachment. The electrode also emits

secondary electrons as a result of its bombardment by positive ions.

Negative ions, heavier than electrons by a factor of approximately 30,000, are repelled by the

negatively charged emitter electrode assemblies 47 away from the ion engine 20, thereby

imparting momentum to the ion engine 20 in the forward direction. In a similar manner if an

electrode is made positive it would then repel positive ions.

The positive ions, heavier than the electrons by a factor of approximately 30,000 are attracted

to and hence accelerate toward the negative emitter electrode assemblies 47, imparting a

momentum to the emitter electrode assemblies 47. This imparted momentum is equal to the

ion mass times their acceleration velocity. The total momentum imparted to the ion engine

20 is equal to the ion density times the momentum of each ion, multiplied by the surface area

of the ion engine. Note that the platform can remain charge neutral by the closed circuit

mentioned above or, in an alternative embodiment, by injection an equal amount of negative

and positive charges.

The Corona Ion Engine can be operated at a wide range of pressures, from atmospheric

pressures down to the low pressures existing at ionospheric heights. Because Corona Ion

Engines can produce at atmospheric pressures thrusts comparable to that of propellers driven

by the same electric power, a launch strategy has been developed as follows:

The Sky Station will be launched from the ground via floatation using a lighter-than-air gas

such as helium or hydrogen. The Corona Ion Engine and the accompanying air compressor

will be used to navigate the Sky Station during the ascent of the Station from the ground up

through the troposphere to the Stratosphere. Unlike an airplane which derives its lift from a

minimum speed, the Sky Station can ascend at a low upward speed using the solar Corona Ion Engine for navigation function.

In preferred embodiments where the Sky Station is in the stratosphere, the atmospheric drag

on the Sky Station is low because of the low atmospheric pressure at stratospheric altitudes.

The propulsion produced by the ion drive is sufficient to counter the dray force so as to move

the Sky Station to its deployment location and maintain the Sky Station in a stationary

position against the modest stratospheric wind. It can be demonstrated that the momentum

flow due to the force off the ion propulsion can be greater that the atmospheric drag. In other

words, the ion momentum is sufficient to keep the platform stationary and still against the

atmosphere wind. The drag force F= C (1/2 $ V) A,

where $ = neutral mass density,

V = neutral flow velocity,

A =surface area of the Sky Station

C =(drag coefficient) = 0.015, is balanced by the momentum flow imparted by the ion engine F = S V A A

where $ = ion mass density,

v=accelerated ion velocity,

A=area of the ion engine. The accelerated ion has a much higher velocity than the neutral atom which explains why the

force due to ions, in spite of the small surface area of the ion engine, can counteract the drag

force of the neutral win. Because the ion density is some fraction of the neutral density the

balance between atmospheric drag and ion thrust can hold for all altitudes.

The atmosphere in the stratosphere is rarefied and is optimal for the ionization of the

surrounding atmosphere by corona with the lowest electric field E. (The characteristic ratio

E/P, where P is the atmospheric pressure, is near the minimum value at stratospheric

pressures.) Thus, the Sky Station, operating in the stratosphere and propelled by ion engines,

can be maintained in a stationary position in the thin atmosphere. In a preferred embodiment,

the light-weight ion engine 20, has no significant moving parts, and is ideal for high-altitude

operations, using solar power as its primary source of energy.

D. Corona Ion Engine.

The Corona Ion Engine, utilizes the principles of corona ionization to produce thrust

by introducing negatively charged emitter electrodes 48 into the atmosphere to eject, by

means of field emission, energetic electrons. These electrons will attach to the positive side

of neutral atoms causing them to become negative ions, thus forming a plasma of electrons,

negative and positive ions that extend away from the corona at the tip 49 of the electrode.

The negative ions are repelled by the negatively biased electrode. The reaction to this

repulsion provides the forward momentum or propulsion, as illustrated in Fig. 1.

Because electrons transfer virtually all of their kinetic energy when they make

ionizing collisions, it is possible to calculate the total amount of momentum developed by the

engine based on the density, velocity and momentum of the ions. The equation for this calculation is L = N (2emV) where L = total momentum, N= number of atoms, e =

elementary charge, m = mass of the atom and V = voltage. This equation does not take into

account engine configuration, system efficiency, or other real-world variables. This equation

shows that the propellant density (N) is the most important factor in the engine's performance

as it has a direct multiplying affect on the engine's thrust (momentum). Since the Corona Ion

Engine uses ambient atmosphere as the propellant, it would follow that the engine intake

should be configured to increase the air density at the electrode. It also follows that the thrust

of the engine increases linearly with the number of electrodes.

The voltage (V) is a secondary influence on the performance and it too is dependent

on the density. The denser the propellant, the more voltage is required to excite the greater number of ions. The limitation on how much voltage can be applied is when sufficient

potential is reached to create an arc. Since there is no load on the electrode, there is very little

if any amperage required.

Ion engines can be used with conventional propellers and without conventional

propellers. In a preferred embodiment the ion engine is solar powered and uses the

surrounding atmosphere as its source of gas. The Corona Ion Engine, a preferred

embodiment of which is depicted in Fig.4, includes emitter electrode assemblies 47, each of

which comprises a plurality of pointed electrodes 48. The electrodes are biased, in this

preferred embodiments, at a negative voltage in the range of -1 to -25 kilovolts, depending on

the ambient atmospheric pressures, to create strong electric field at the tip 49, which serves to

eject energetic electrons into the surrounding atmosphere. The emission of electrons can be

enhanced by the concurrent irradiation of the electrode by focused solar ultraviolet radiation.

Such focusing can be achieved with a lens.

A positive electrode, not depicted in Fig. 4, is positioned in the vicinity (1-5 cm

distance) of the emitting electrode assemblies 47 to complete the circuit; as a result there is

no build up of charges on the engine, allowing it to sustain continuous operation. The

emitted electrons are accelerated by the surrounding electric field, forming a plasma of

electrons, negative ions and positive ions, by the process of ionization and charge attachment.

The electrode also emits secondary electrons as a result of its bombardment by positive ions.

In a preferred embodiment of the present invention, a electrode, which is comprised of

a plurality of elongated members with sharpened ends which face a second electrode, is a

cylinder, and the second electrode is a toroid, with the axis of the first electrode aligned with

the axis of the second electrode such that an atmospheric gas which is partially or highly

ionized can flow past the first electrode and then past the second electrode. A means for

creating a voltage difference between the first and second electrode is present such that the

first electrode propels the atmospheric gas toward the second electrode. The voltage

difference between the first and second electrode is sufficient to create a charge distribution

on the surface of the first electrode such that, in a preferred embodiment, the atmospheric gas

achieves a charge density of one million charged particles per cubic centimeter or greater.

Further, this voltage difference between the first and second electrode is sufficient to emit

electrons with energies sufficient to produce an avalanche of secondary electrons within the

atmospheric gas in the vicinity of the first electrode. In a preferred embodiment the

ionization means includes a radio frequency coil (RF).

In yet another preferred embodiment of the present invention means are provided to

limit the electrical current passing through the first electrode to prevent "arcing" from

occurring. In this preferred embodiment a ballast resistor is utilized to prevent this "arcing" process, as shown in the schematic of a preferred embodiment of the Corona Ion Engine

circuitry.

In another preferred embodiment an RF voltage may be imposed on a coil positioned before

the first electrode so as to increase the number of ions in the stream passing between the

electrodes.

It is contemplated in yet another preferred embodiment of the invention that the

emission of electrons from the first electrode may be increased by the direct irradiation of

light or sunlight by use of a focusing lens. This process focuses sunlight on the electrode to

increase electron emission.

As indicated in the formula outlined herein, the propellant or atmospheric density is

the most important factor in the performance of the ion engine and as such it is critical that

there be means by which density of the ambient atmosphere may be increased. This may be

accomplished by increasing the velocity or arrival rate of the ambient atmosphere through the

engine so that greater numbers of charged particles are incorporated into the stream flowing

through to the electrodes. In a preferred embodiment this increased velocity or increased

arrival rate is accomplished by utilizing a fan or an air compressor to accelerate the ambient

particles. It is also contemplated in yet another preferred embodiment that the arrival rate of the ambient atmosphere is increased by the use of a hom-shaped cylinder or housing for the

electrodes. This cylinder shape has the effect of focusing the stream of charged particles

through the engine with a resulting increase in the particle stream density reaching the

electrodes of the engine.

E. Power Sources in Alternate Preferred Embodiments. Sky Station™, in a preferred

embodiment, drives its primary power from solar energy, using solar energy, using solar

panels on its surface. These solar panels can be combined in scries or in parrel to provide

appropriate voltage to the various electrical devices on board. The energy from solar cells can

be stored, in a preferred embodiment, in fuel cells which can supply energy during night-time

conditions. In alternative preferred embodiments, solar power can be focused onto a surface

to produce heat, raising the temperature of the surrounding gas. The discharge of this heated

gas will generate propulsive force and can be used to produce electrical power as is known in

the art. In other alternative preferred embodiments, solar power can also be focused onto a

metallic junction formed from two dissimilar elements. The heated metallic junction then

acquires an electric potential with respect to a cold junction through the phenomenon called

"thermoelectric effect," thus providing electrical power.

In addition to fuel cells and batteries, the Sky Station Global network can be self-sustaining

in that two or more Sky Stations may provide energy for each other. As depicted in Fig. 3 the

Sky Stations which are in the sunlit zone can transmit energy through a microwave link.

Since the Sky Stations operate in rarefied atmosphere, a high power communication link is

feasible because of the low scattering by the atmosphere.

F. Propulsion Source in Alternate Preferred Embodiments. In addition to the preferred

embodiment of the invention involving the Corona Ion Engine TM is the use of a vertical sail

to catch the wind in such a way that a relative motion with respect to the wind result from the

differential pressure between the two surfaces of the sail, similar to that on a boat. The sail

normally lies horizontally until deployment. In another alternate embodiment, the use of

windpower reduce the thrust required by an ion engine

Further alternate preferred embodiments employ solar power to heat gas which is to be

ejected. The momentum of the exhaust gas can be increased if its temperature is increased by

solar power which can be focused by suitable lenses onto a surface. The air in contact with

the heated surface will then become heated, resulting in a higher thrust from the exhaust.

3. Control Systems. In the preferred embodiment depicted in FIG. 1 , the Sky Station TM 10

uses a control system, not depicted in FIG. 1 , based on multiply redundant Global Positioning

Systems receivers, interfaced via an on-board position-control systems to the Corona Ion

Engines TM 20. This control system, in this preferred embodiment, autonomously enables

Sky Station TM 10 to remain fixed in position to within 100 feet in all three dimensions, and

further enables each Sky Station TM 10 antenna assembly to remain accurately oriented with

a maximum deviation of 0.1 degrees in any direction. In addition, a GPS information and

Corona Ion Engine TM activation data, in the preferred embodiment depicted in FIG. 6, are

continuously downlinked to Sky Stations 85 via embedded telemetry links 91. Thus,

capability always remains for ground controllers to navigate and control each Sky Station TM

via telemetry commands.

In a preferred embodiment, all but one primary and one back-up ground station will be mere

"slave station" that collect telemetry data and send control information, but do not originate

the control signals themselves. In this preferred embodiment, control signals will be

originated only at the primary and back-up ground stations where expert engineers will be in charge. The primary and back-up control facility, in this embodiment, will use standard

telecommunications links to remain in contact with the slave station control facilities. In an

alternate embodiment, transportable slave ground station will be available for shipment

anywhere in the world on short notice. In altemate preferred embodiments, celestial

navigation, radio location, and other techniques know in the art may be used to regulate the

position of the Sky Station TM 10. It should be noted that there are few position-disturbing

forces in the stratosphere, which is above 99.9 percent of the oxygen atmosphere. Worst case

stratospheric "winds" do not exceed 1.5 miles per hour.

Communications Systems. In the preferred embodiment depicted in FIG. 6, the

communication systems of the present invention comprises the stratospheric communications

payload, ground station 88 and user communicators 87. All three of these systems exchange

digital information in demand-assigned 64 kbps (ISDN-B) channels. In alternate preferred

embodiment, these systems exchange information according to other signals types, other

bandwidths or other protocols know in the art.

The Stratospheric Payload. In this preferred embodiment, the stratospheric payload,

not depicted in FIG. 6, consists of a 47 GHz band beam-forming phased array antenna and a

very large bank of regenerative processors that handle the functions of receiving, frequency

demuxing, demodulating, decoding, data multiplexing, switching, encoding, modulating and

transmitting. The stratospheric communications payload, in this preferred embodiment,

reliably receives, regenerates, switches, and retransmits over one-half million transmissions

simultaneously for a period of not less than ten years. Filters segment the incoming

communications stream based on phased array information and frequency.

Separate 32dBi transmit and receive antennas are used in this preferred embodiment, each

about 8 inches in diameter. A millimeter waveguide feed array projects a large number of

cellular coverage areas on the surface of the earth. The precise power allocated to each

cellular coverage area, and its boundary, are capable of being changed via ground control

center commands. In alternate embodiments, other types of antenna systems know to the art

may be used.

In this preferred embodiment, the Stratospheric Payload requires 160 kilowatts of end-of-life

power. This power may be allocated equally to each of 2,100 cells, or may be differentially

allocated among cells based on channel demand, or based on the need to provide more transmit power to outlying cells. As an example, if each Stratus TM communicator 87

requires 100 milliwatts of payload power, the communications payload has an overall

capacity of approximately 1.6 million simultaneous Stratus TM communicators 87. Of course

not all of these Stratus TM communicators 87. Of course not all of these Stratus TM

communicators 87 can be accommodated in the same geographical area due to frequency

constraints. If an embodiment of this invention is assigned initially 10 MHz of user spectrum

for transmission to the Sky Station telecommunications facilities and 10 MHz of user

spectrum for transmission from the Sky Station telecommunications facilities, there would be

adequate bandwidth and power for 20 simultaneous users per cell. At 70 kHz per

communicator (half duplex), this capacity calculation requires only 1.4 MHz per cell, and

with hexagonal-pattern frequency reuse, only 10 MHz per Sky Station user link (half duplex),

In such a preferred embodiment, maximum power utilization of this bandwidth occurs with

76 watts per cell. In and altemate preferred embodiment, the invention may use substantially

less power per cell but retain the ability to power additional bandwidth per cell.

In a preferred embodiment, there would be 100,000 subscribers per Sky Station. Assuming

further that these $100,000 subscribers were evenly distributed across 2,100 cells, there

would be 47 subscribers per cell, and 100,000 subscribers in a 400,000 square mile coverage

area. This is a reasonable fit with the 20 users per cell bandwidth limited loading capacity

calculated above, especially since subscribers are likely to be on-line for only part of the time.

In a preferred embodiment, the Stratospheric Payload may incorporate a state-of-the-art

baseband switching matrix. This technology has evolved rapidly in the past few years as a

result of both NASA and ESA funded programs. Complex satellite baseband processors are

now well known to the art.

The overall number of discrete electronic components required for the preferred embodiment

of the Stratospheric Payload depicted in FIG. 6 is large compared with that normally

implemented in satellite communication systems. However, even taken as a whole, the

embodiment's requirement for thousands of electronic circuits per Sky Station™ multiplied

by, for example 250 Sky Stations™ in a global telecommunications system, still totals only a

fraction of the electronic switched circuit requirements of the PSTN, and much less than projected electronic switched circuits for the cellular mobile telephone industry by the year

2005.

b. Ground Stations. In the preferred embodiment depicted in FIG. 6, several

geographically-spaced digital switches, are associated with each Sky Station™ coverage area,

providing each digital switch interface to the PSTN and the Internet. The switches, located at

ground station 85 or other locations will be designed to handle the maximum number of

simultaneous calls. Calls will be routed to the most appropriate switch based on information

determined at the Sky Station™ baseband processor in accordance with on-board

programming. In a further preferred embodiment, each switch also serves as an Internet

gateway site.

In the preferred embodiment depicted in FIG. 6, the ground stations 85 serve as base stations

in the communications network. Accordingly, each ground station 85 is assigned a block of

bandwidth appropriate to its needed call handling capability. This bandwidth is reused in

each polarization, and can be reused again at another ground station 85 a short distance away

due to the narrow beam width that prevails at 47 Ghz. The amount of bandwidth needed for

each ground station 85 is approximately equal to the number of active cells divided by the

number of ground stations 85 time the bandwidth assigned to each cell 84 times the frequency

reuse factor. However, this amount of bandwidth may vary considerably over time and will

be reduced over time as greater numbers of calls occur among Stratus™ Communicators 87

in the same Sky Station™ Communicators 97 in the same Sky Station™ coverage area rather

than through the PSTN.

c. Stratus™ Communicators. In the preferred embodiment depicted in FIG. 6,

Stratus™ Communicators 87 are small personal communications device using solid state

MMIC technology and capable of greater than 5% frequency stability. In this preferred

embodiment, these Stratus™ Communicators digitize and format incoming information in

accordance with the ITU-T H.263 audio-video compression algorithms, impress the same

upon a 70 KHz carrier, and transmit this information using a small antenna. Each Stratus™

Communicators 87 has a unique ID code that enables it to extract communications intended

for it from downlinked transmissions at the 48 Ghz frequency.

The Stratus™ Communicators 87, in this preferred embodiment, have a modular ability to be

augmented with other telecommunications links such as cellular, PCS or unique nationally-

authorized frequencies for indirect Sky Station™ access via relay transmitters. These

Stratus™ Communicators are also be capable of direct interface to the PSTN. The recently

announced Oracle Internet device is a typical format for a Stratus™ Communicator.

In the preferred embodiment depicted in FIG. 6, upon triggering the "send" button a Stratus™

Communicator 87, the Sky Station™ 10 communications payload will assign an uplink

channel 93 to the Stratus™ Communicator. As the incoming message is received, its header

will be scanned for the telephone number of the intended recipient. If the recipient is part of

the Sky Station™ network, an attempt will be made to connect directly to that recipient

without the use of a ground station 85, i.e., via a simple header reformatting process and

retransmission. Each Sky Station™ 10 and each switching center maintains a database

listing, continuously updated, of the last location of each Sky Station™ subscriber based on

his last telephone call or system inquiry. In this preferred embodiment, a software program

directs a logical search for the intended recipient based on last known locations, cost and

quality of the relevant PSTN, adjacent cell geometry and adjacent Sky Station™ geometry. If

the incoming message indicates a recipient who is not a Sky Station™ subscriber, the call is

automatically directed into an available ground station channel for interconnection to the

PSTN. It is estimated that this embodiment of the Stratus™ Communicator can be built

around a hybrid analog/digital VLSLASIC, with approximately 100,000 logic gates and .25

micron technology.

In another preferred embodiment, a Stratus™ Communicator 87 also includes a cellular

phone capability that will be accessed whenever Sky Station™ 10 is unable to complete a

communication, due for example to building blockage or any other short-term disruption in

service. If such a Stratus™ Communicator 87 cannot receive transmissions from the Sky

Station™ 10, then the intemal logic of Stratus™ Communicator 87 automatically looks for a

free cellular phone channel. Blocked transmissions are, however, less likely with

stratospheric platforms than with low earth orbit platforms because in major metropolitan

areas the former are generally at much higher angles of elevation.

In a preferred embodiment, security features built into the Stratus Communicator 87 will

emulate those of cellular and personal communications services. There will be password

protection for access to the Internet web capability. Theft of service, in a preferred

embodiment, can be prevented by the invention since all signals pass through a Sky Station

switch. This switch, in altemate preferred embodiments, may be located onboard each Sky

Station or at a ground switching center. In either case, upon any indication of theft of service,

switches throughout the telecommunications network, in a preferred embodiment, will be

able to block any calls using a suspect Stratus Communicator ID number.

Altemate preferred embodiments of the Stratus Communicators 87 may use different radio

frequencies, protocols and transmission types and fabrication technologies as is known in the

art. Altemate preferred embodiments of these communicators may have a variety of special

purpose functions, for example, a single button which sends a distress call or medical alert

signal which is transmitted by the Sky Station™ to appropriate authorities. Altemate

preferred embodiments of the communicators may also provide picturephone capabilities.

d. Antennas. In a preferred embodiments which are not depicted, Stratus™

Communicators are equipped with different optional antennas depending on their intended

zone of usage. Stratus™ Communicators intended for automobile or truck use may come

with either a simple 3dBi external antenna for city use (much like a cellular telephone car

antenna), or with an automatically steerable or electronically steerable phased array 23dBi

antenna for highway /rurual use (much like a geostationary mobile satellite antenna).

Stratus™ Communicators, in a preferred embodiment intended for portable city use, where

angles of elevation are high, will have an inconspicuous embedded antenna. However, for

frequent indoor use, there may be a powered infrared remote antenna that can attach to a

window and connect to the Stratus™ Communicator at infrared wavelengths.

Stratus™ Communicators, in a preferred embodiment intended for use in outlying areas is

hundred miles from a metropolitan area, will work with a small 23dBi one-inch antenna,

about the size of a business card, the 15 degree half power beamwidth of which will make for

easy pointing. By simply typing in coordinates or a town name, this extended coverage

Stratus™ Communicator may automatically point the build-in one inch antenna based on

information stored in its memory as to the location of the nearest Sky Station™. A built-in

video screen in alternate preferred embodiments of the Stratus™ Communicator may also use

iconic figures to show the user which way to face for a connection to the best path Sky

Station™. The user would be told if an obstacle is blocking the communications path. In this

preferred embodiment, the total Stratus™ Communicator memory requirement for pointing

information is less than 2 Mbytes.

For Stratus™ Communicators used at very low angels of elevation, or at horizon distances as

far as 350 miles from a large city, a preferred embodiment includes a five inch mini-dish

antenna to maintain communications with a Sky Station.™ This 36 dBi antenna may be

permanently mounted with a clear line-of-site, and would have nearly the same half power beamwidth as a DirecTV dish. In a Footprint Area Coverage zone, an example of which is

shown as FAC 82 in FIG. 6, dishes included in preferred embodiments of the Stratus™

Communicator may also be capable of rotating in azimuth, and modestly in elevation, in

order to lock-on to the strongest Sky Station™ signal. Thus, the invention can Use site

(geographic) diversity to overcome propagation challenges at 47 GHz or other frequency

ranges. As is known in the art, altemate preferred embodiments of the Strarus™

Communicator may use other types of antennas.

D. Technical Description of Telecom Links used in a Preferred Embodiment.

The preferred embodiment of the invention depicted in FIG. 6 includes four different

telecommunications links that occur within three different telecommunications links that

occur within three different service environments: High Area Coverage (HAC) 80, Wide Area

Coverage (WAC) 81, and Footprint Area Coverage (FAC) 82. This embodiment is designed

to provide highly useful and low-cost telecommunications services, notwithstanding the

severe challenges of radio frequency challenges in the 47 Ghz band, by relaxing the 99.9% availability constraint engineered into most wireline and fixed satellite systems to a 98%

availability figure. This 98% availability figure is still much higher than most people, eve in

developed countries, expect from a mobile or portable communications system, and is much

higher than most people in developing countries can achieve from their wireless systems.

At 98% availability there is virtually nowhere in the world where the atmospheric attenuation

(water vapor plus gas) at 48 GHz exceeds 1.1 dB/km of path length up to the freezing height.

In other words, since more than 90% of the attenuation is due to water, propagation tables

show there is virtually nowhere in the world that receives more than about 2.8 mm/hr of

rainfall (1.1 dB/Km loss) for more than 2% of the year, or about 180 hours out of the 9000

hour year. While 2% outage is unacceptable for television broadcasting and other

communication systems, it may be entirely acceptable in some preferred embodiments of the

invention as a reasonable penalty as part of a low-cost wide-band telecommunications

system. Furthermore, it must be emphasized that this 2% outage figure is a worst case

number ~ in the vast majority of the world, 2.8 rn hr rainfalls occur less than 1% of the

time. Altemate preferred embodiments may use additional Sky Stations™, at the same or

different attitudes to provide higher levels of availability.

In the preferred embodiment depicted in FIG. 6, Sky Stations™ 10 a geostationary at an

altitude of approximately 30 kilometers above the earth. From this altitude, the propagation

margin for atmospheric losses and coverage areas associated with the Sky Station™ 's three

grades of service are shown below:

It should be noted that the atmospheric loss propagation margin is substantially less than the

range to a Sky Station™ 10 multiplied by the 1.1 dB/Km loss figure. The reason is that over

90% of the atmospheric loss occurs due to water located in rain cells that are limited size and

98% of the time, much smaller than the range to a Sky Station™. Also, as depicted in FIG. 6,

most FAC 82 users in this preferred embodiment are in the FAC 82 of more than one Sky

Station™ and can use site diversity to select the path with fewest rain cells.

With regard to the HAC 80 service grade in this embodiment, simple cellular phone type user

terminals is able to directly access the Sky Station™, as shown in the link budget provided

below. As to the WAC 81, users in this embodiment have the option of accessing the Sky

Station™ directly via a modest gain antenna, or accessing it indirectly via a frequency

coordinated relay transmitter. Finally, in the FAC 82 zone, users in this embodiment have the

option of accessing the Sky Station™ directly via a high gain antenna, or accessing it

indirectly via a nationally coordinated relay transmitter. In this and altemate embodiments,

high gain antennas for FAC 82 zone reception may also be capable of rotating to access a Sky

Station™ with the best propagation conditions. For example, if rain conditions are worse for

one particular Sky Station™ path, the FAC ground station could shift to another Sky

Station™ that has overlapping FAC coverage. It is important to note that in some preferred

embodiments, as additional Sky Stations™ are deployed, users will often find themselves

having WAC replace their FAC, and HAC replace their WAC.

1. Downlink Budge (Sky Station™ to User). The downlink budget assumes an

information rate of 64 Kbps with FEC encoding and the following Modulation Parameters:

MODULATION PARAMETERS

2/3 rate K=7 96 Kbps convolutional

Reed solomon 106 Kbps for 10% depth

OPSK: 56 Ksym sec

Occupied Bandwidth: 67 KHz

Channel Bandwidth: 70 KHz

Eb/ No for lO ^"5 BER 6 dB

(soft decision 5 bits with coherent demodulation)

It will be noted that in this preferred embodiment 400 milliwatts is provided in the FAC region

as compared to the 100 milliwatts in the HAC and WAC regions. AS noted earlier, each cell

in the Stratospheric Payload in some preferred embodiments may have the ability to receive an

allocation of greater power. This could be used to increase capacity, or to help overcome the

particular moisture environment of particular cells, or to reduce antenna gain requirements.

The downlink budget for this preferred embodiment is as follows:

EXEMPLARY DOWNLINK BUDGET

Parameter HAC Value WAC Value FAC Value

Power/User 100 mW 100 mW 400 mW

-lO dBW -lO dBW -4 dBW

Platform Gain 32 dBi 32 dBi 32 dBi

Slant Range 58 km 164 km 600 Km

Free Space Loss -162 dB -171 dB -183 dB

User Gain 3 dBi 23 dBi 36 dBi

Power Received 137 dB -126 dB -1 19 dB

Power Noise -153 -153 -153

C/N 16 dB 27 dB 34 dB

Required Eb/No

for 64 Kbps

10 ^{"5 BER} 6 dB 6 dB 34 dB

Margin, down

for Propagation

Losses lO dB 21 dB 28 dB

The downlink budget from the Sky Station™ to the ground station for this preferred embodiment

is essentially the same as above except that only a small amount of power, approximately half

a milliwatt, is allocated to each user since a high gain antenna may be implemented at the ground

station. The resultant margin can be set as high as necessary to handle the anticipated downlink

traffic load.

2. Uplink Budget (User to Sky Station™). In a preferred embodiment, the uplink

budget is set by the need to keep user terminal power in the HAC region as low as possible to

minimize battery power requirements and to respect radiation hazard limits. Accordingly, the

user terminal uplink power is set, in this embodiment, at 100 milliwatts (0.1 watts). Higher

power is acceptable in the FAC zone because the transmitter itself is not portable but may instead

be affixed to a mini-earth station outdoors or by a window. The following uplink budget results

for the high angle, wide angle and footprint angle coverage regions, assuming the same

modulation characteristics provided in subsection (1 ) above.

EXEMPLARY DOWNLINK BUDGET

Parameter HAC Value WAC Value FAC Value

Power/User lOO mW 100 mW 400 mW

-10.0 dBW -10.0 dBW -4.0 dBW

User Ant. Gain 3.0 dBi 23 dBi 36 dBi

Occup. Bandwidth 70 KHz 70 Khz 70 KHz

Slant Range 58 km 164 km 600 Km

Free Space Loss -162 dB -171 dB -183 dB

Platform Gain 32 dBi 32 dBi 32 dBi

p _B 137 dB -126 dB -119 dB

p _N -153 dB -153dB -153 dB

C/N 16 dB 27 dB 34 dB

Data Range 64 kbps 64 kbps 64 kbps

Required Eb/No 6 dB 6 dB 6 dB

Atmospheric

Propagation

Margin, down 10 dB 23 dB 28 dB

The uplink budget from the ground station to the Sky Station™ for this embodiment is

essentially the same as above, except that even higher gain antennas may be used to achieve as

high a margin as is necessary.

3. Geographic Coverage. The geographic coverage objective for a preferred

embodiment of the invention is all of the world's major metropolitan areas and at least 80% of

the world's population. This coverage objective could be accomplished with 250 Sky Stations™.

Each Sky Station™ would be positioned over one of the 250 largest metropolitan areas. In this

embodiment, each Sky Station™ 10 provides WAC to approximately 77,000 square kilometers,

representing the roughly one billion people that live in metropolitan areas, and FAC to the rural

remainder of 80% of the world's population. Sky Stations™ could be postponed so that the

highest density population centers HAC.

In this preferred embodiment, each Sky Station™ coverage area will consist of approximately 2,100 cells, with cells becoming increasingly larger as one emanates radially outward from

zenith. Approximately 700 cells in the HAC region have an average size of five square miles.

The average cell size will be fifty square miles in the WAC region and 500 square miles in the

FAC region.

Approximately 700 cells receive High Angle Coverage, while another 700 cells will enjoy Wide

Angle Coverage. The remaining cells fall within the Footprint Angle Coverage contour. In this

preferred embodiment, each cell receives a bandwidth assignment of one-seventh of the

bandwidth allocate to the user links. The cells share the bandwidth in a hexagonal frequency

reuse pattern to avoid adjacent cell co-frequency operation. In this embodiment, power and

bandwidth are dynamically assigned to cells based on channel demand, subject to overall power

and bandwidth reuse limitations. Ground station bandwidth is also be geographically reused

within each Sky Station™ in a similar hexagonal pattern. Ground station bandwidth may also

be reused among different instances of this invention assuming adequate spatial separation of

their locations.

It will be apparent to those skilled in the art that various modifications can be made to this

invention of a telecommunications platform for use at altitudes up to and including the

stratosphere without departing form the scope or spirit of the invention. It is also intended that

the present invention cover modifications and variations of the telecommunications platform for

use at altitudes up to and including the stratosphere, provided they come within the scope of the

appended claims and their equivalents.