Possible invention disclosu- Minimal Solar power Satellite syste

Well thought out except for cost. Earth based systems are much
cheaper and easier to build...and to maintain.

The key difference is the launch costs for a solar satellite. Launch
costs must come down before any solar satellite system becomes
"profitable".

This leaves only governments that dont have to worry about profits as
prime constructors.

Given the backlog of satellites vs launchers, it's doubtful that a
MEO system would be launchable in 5 years (2012), but perhaps in 10
to 20 (2017 to 2027).

David

--- In ssi_list@... "Charles F. Radley"
>
> Possible invention disclosure - Minimal Solar power Satellite
system
> in Medium Earth Orbit
>
> Charles F. Radley, 22 August 2007
>
> I cannot afford to pay patent attorneys, and it seems better to
> simply
> help something happen, rather than trying to protect IP at this
> point.
> Hence I offer the following public disclosure.
> Context of the Disclosed Invention:
> The concept of Solar Power Satellites (SPS) was proposed in 1968,
and
> patent
> was filed and approved for Peter Glaser on that invention, 1973
U.S.
> patent number 3,781,647 [3] for his method of transmitting the
power
> to Earth using microwaves. At that time a geostationary orbit
(GEO)
> was proposed.
> Major challenges of GEO include
> 1) very high launch cost versus MEO/LEO
> 2) very large path distance requiring antenna/rectenna sizes which
> far
> exceed the state of the art at the proposed frequencies (e.g. 2.45
> GHz, 5.8GHz)
> In recent years mobile communications satellites have been deployed
> in
> LEO (LEO). Benefits of LEO versus GEO include much lower launch
> cost (about 7 times cheaper per kg) and much shorter beam path
> distance (e.g. 500 km versus 35,680 km) allowing antenna sizes 70
> times smaller diameter.
> A LEO space power grid has been proposed as a precursor to GEO
space
> power beaming system: Komerath, N.M., Boechler, N., "The Space
Power
> Grid". IAC-C3.4.06, 57th International Astronautical Federation
> Congress, Valencia, Spain, October 2006.
> However, LEO presents several formidable challenges for satellite
> solar power beaming to the Earth. High amongst these is the need
for
> adaptive beam steering, requiring a sophisticated phased array
> antenna
> to track rectenna on the Earth with very large relative motion
> velocity, whilst simultaneously tracking the Sun.
> Other challenges of LEO include: lack of solar illumination (in
> darkness 50% of the time), and difficulty rejecting waste heat due
to
> the large size of the terrestrial disk occupying close to half the
> sky. Also, proximity to the Earth surface results in close horizon
> and only a small area of the Earth can be covered by each
satellite,
> requiring large numbers (e.g. dozens) of satellites to achieve
global
> coverage, compared with only three GSO spacecraft to achieve the
same
> near-global coverage.
> ---------------------
> Description of Invention:
> An arrangement of satellites has been invented in MEO which
overcomes
> most of the problems of LEO, and gains most of the benefits of GEO
at
> much lower cost.
> At an altitude of 11,000 to 12,000 km above the Earth, radiation
> levels are relatively low and benign, lower than at GEO.
> At this altitude launch costs are modest compared to GEO, but more
> expensive than LEO.
> A satellite in a circular orbit at 11,000 km will have an orbital
> period of about 6 hours, so a sun-synchronous orbit can be achieved
> with exactly four orbits per synodic day.
> The special innovation is that the orbit plane shall be be
orthogonal
> to the ecliptic.
> The eclitpic is the Earth's orbit around the Sun, which is inclined
> at
> an angle of 23.3 degrees to the Earth's equator (the tropical
> latitudes).
> The basic minimal constellation is proposed to comprise four
> satellites in two orbit planes. Each orbit plane is orthogonal to
> the ecliptic, and orthogonal to the other orbit plane. Each
> satellite orbit is inclined at 66.7 degrees to the equator.
> At this altitude and inclination the following properties are
> present:
> 1) approximately 30% of the Earth's surface is visible to each
> satellite
> 2) each satellite is in sunlight approximately 90% of the time
(most
> of the year continuous sunlight, for a few weeks in eclipse season
> satellite is in darkness about 20% of each orbit)
> 3) Beam path length is about 30% versus GEO, affording
corresponding
> smaller antenna and rectenna
> 4) Each satellite in each orbital plane is at 180 degrees to the
> other
> satellite in the same orbital plane.
> 5) Each satellite pair (in one plane) is at 90 degrees phase to the
> other pair (in the other plane), meaning that a neo-tetrahedral
> configuration is maintained, thus every point on the entire world
is
> in the field of view of at least one satellite for about 90% of the
> time.
> 6) The special distinction versus LEO is that no beam steering is
> required, so in this respect the satellite design is very similar
to
> a
> GEO spacecraft. Because the Sun/Earth angle is always 90 degrees, a
> constant fixed axis rotating antenna despun platform can be
employed.
> The solar array tracks the Sun, and a despun platform tracks the
> Earth, rotating once every six hours. No dynamic beam steering is
> required, unless there is a need to serve a different rectenna on
the
> Earth (this is no different than for a GEO spacecraft).
> 7) For a nearly half the time, the MEO constellation would be able
to
> provide better service than GEO satellite to rectennas in high
> latitudes; e.g. north of 34 degrees north (and south of 34 degrees
> south). This is because for approaching half of each orbit the MEO
> satellite would be at a higher elevation above the horizon than an
> equatorial GEO satellite.
> Prior Art:
> Some basic literature search has found no mention of this
particular
> satellite constellation. Hence it is believed to be an original
> invention. The TRW company has several US Patents and
> International/European Petents for the ICO/Odyssey satellite
> constellation at the MEO altitude at approximately 11,000 altitude.
> However, those orbits are not orthogonal to the ecliptic, and are
> intended for mobile communication rather than space power beaming.
> The TRW patents do not appear to claim intellectual protection of
the