Super-heavy lift reusable launcher

"Pat Flannery" wrote in message
news

At least Sea Dragon got into that engine size category:
http://www.astronautix.com/lvs/searagon.htm

Again; imagining something and actually making it happen are two different
things.

On Aug 9, 4:35 am, wrote:
On Aug 9, 7:12 am, "Martha Adams" wrote:



"Alan Erskine" wrote in message

...

wrote in message
...
Imagine ahydrogenoxygen rocket engine with an exit nozzle diameter
of 17 meters in diameter, 36 meters long and produces a thrust of
53,300 tonnes with a specific impulse of 450 seconds.

Not even if I were using drugs would I be able to imagine something so
ridiculous as this.

============================================

"Ridiculous" is a very bad word, because it shuts-off
thinking. I might go for "extravagant," but I'd like
to point out, if it's out toward the far end of a
good imagination, it's realistic, and I have guessed
a scenario where the national effort would be directed
to building a "small" fleet of these things. If you
restart your thinking, maybe you can guess something
too.

Titeotwawki -- mha [sci.space.policy 208 Aug 09]

Reading declassifie reports about what is possible also helps. What's
surprising is that many of these reports are 50 years old - and are
based on sound engineering and materials science practices of the
1940s and 50s. Using today's abilities - we can far exceed the
visionary thinking of the 50s - if the folks doing the thinking had
the technical skill to design a rocket with a slide rule and handbook
of materials! lol.

If we put those physics and science smart Zionists/Nazis of the 50s in
charge (aka New World Order), most all of what you suggest should
happen in short order.

Is that your plan?

Perhaps as long as we're at $50+ trillion in debt, what do we got to
lose?

~ Brad Guth Brad_Guth Brad.Guth BradGuth

On Aug 9, 2:23 am, Ian Parker wrote:
On 9 Aug, 04:57, wrote:



Imagine ahydrogenoxygen rocket engine with an exit nozzle diameter
of 17 meters in diameter, 36 meters long and produces a thrust of
53,300 tonnes with a specific impulse of 450 seconds.

Now imagine a three stage rocket built around this engine.

The first stage

Consists of a truncated cone that has a base diameter of 196.96 meters
and a ring of 36 engines around the base - exhausting into a zero
height aerospike engine arrangement - that doubles as a re-entry heat
sheild. The vehicle has 316 support legs around the base to form its
own self supporting platform. These legs are equipped with powered
wheels that allow the vehicle to move on the ground after landing and
before take off. The legs also have powered anchors, reusable hold
down clamps. The stage length is 154.88 meters. The stage masses
217,415 metric tons empty and carries 136,164 metric tons ofhydrogen
in a single spherical tank 154.88 meters in diameter. At the base of
the cone, above the 36 engines are 8 smaller oxygen tanks each 27.76 m
in diameter, together they carry 816,988 metric tons of liquid
oxygen. Total stage weight is 1,225,567 metric tons. All 36 engines
produce nearly 2 million tons at lift off.

The second stage

Consists of a smaller truncated cone that has a base diameter 112.81
meters. It is equipped with a ring of six engines around the base -
exhausting into a zero height aerospike engine - that also doubles as
a re-entry shield. The vehicles has 36 support legs around the base
to form its own inter-stage connection during lift-off and landing
gear during vertical touchdown. The legs are powered and can also
operate as anchors as above. The stage length is 88.71 meters. The
empty stage masses 50,993 metric tons and carries 25,582 metric tons
ofhydrogenin a single spherical tank that is 88.71 meters in
diameter. At the base of the cone, above the 6 engines are 8 smaller
oxygen tanks each a sphere 15.90 meters in diameter. Altogether the 8
tanks carry a total oxygen load of 153,495 metric tons. Total stage
weight is 230,070 metric tons.

The third stage

Consists of a smaller truncated cone that has a base diameter of 64.61
meters. It is equipped with a single engine at its base - exhausting
at the center of a heat sheild that is equipped with a door. Smaller
vernier engines surround the heat sheild for vehicle recovery. There
are 6 support leges around the base to form its own inter-stage
connection during lift off and operate as landing gear during vertical
touchdown. The legs are powered and can also operate as anchors. The
stage length is 50.81 meters. The empty stage masses 9,580 metric
tons and carries 4,806 metric tons ofhydrogenin a single spherical
tank 50.81 meters in diameter. 28,839 metric tons of oxygen are
carried in 8 tanks each 9.11 meters in diameter. Total stage weight
is 43,225 metric tons.

Payload fairing

The payload fairing rides atop the third stage, and ispart of it. It
consists of 6 clamshell type doors that open 20 degrees and are self
powered and have a powered clamping mechanism. The fairing base sits
atop the third stage and is 37 meters in diameter and has an overall
length of 91.94 meters. It is cylindrical from the base for its first
23.78 meters. It then tapers at a half angle of 15.75 degrees until
it comes to a point another 68.16 meters above the top of the
cylinder. Total volume within the fairing 50,000 cubic meters. Total
payload capacity 10,000 metric tons.

Piloted option

Around the base of the payload fariing is a 37 meter diameter torus
that is 3 meters in diameter - this 116 meter long ring is equipped to
carry a crew of up to 35 - although the vehicle is capable of
unpiloted operations. 90 tele-operated humaniform robots are attached
throughout the fairing volume to allow operators in the pressurized
zone access to the cargo and spacecraft. These robots may also be
teleoperated from the ground.

Notes on Cost:

Fighter aircraft and spacecraft range in prices from $5 million to $10
million per ton. Transport aircraft range in prices from $1 million
to $1.8 million per ton. Cargo ships cost $1,500 to $2,000 per ton.
The variation in cost has to do primarily with non-recurring
engineering charges, scale of production, and volume produced - to a
smaller degree the sort of environment and the nature of the materials
used play a part. On the scale we're discussing here - it should be
possible to achieve $2,000 per ton for structure cost, and $20 per ton
propellant cost. This means each vehicle can be built for $664
million - the payload costs $20 million - and recurring cost per
flight is $48 million.

Notes on Size:

Total mass of the empty vehicle is 331,986 metric tons. This is about
the size of a very large ocean going ship. Its total length when
fully stacked is 386.34 meters. Total mass at lift off is nearly 1.5
million tons and it burns nearly 1.2 million tons of propellant.

Operation

The first stage lights, and powers up, and the anchoring gear
releases. The stage rises at 1.3 gees. When the vehicle reaches 3.5
km/sec the stage falls away and re-enters downrange. There it
executes a powered touchdown at a downrange field. There it is partly
refueled and flown back to the launch center ballistically, in a
'bounce back' maneuver. At the launch center it re-enters, lands -
and motors over to the launch center again to be reused.

The second stage ignites and continues upward achieving a final speed
of 7.7 km per second and placing the fully loaded 53,225 metric tons
into LEO. The second stage after release of the third stage, deorbits
and re-enters so that it lands vertically in a powered touchdown near
the launch center. Once down, it motors to the 400 meter tall
assembly crane where it is placed atop the booster stage once again.

The third stage ignites and enters a GTO and rises to GEO. There it
executes a circularizing burn - and releases its payload after opening
its nose shroud. Once the payload is released and the payload
successfully deployed, the reusable kick stage, deorbits slowing to
GTO velocity, and re-enters the atmosphere and lands at the launch
center - motors over to the tower, and is placed again on the stack
after refurbishment.

Once the stack is assembled, the vehicle is then refueled and reused.

A fleet of 6 vehicles are built to deploy 52 payloads per year - with
a cycle time of 6 weeks.

* * * *

You are assuming that heavy lift is need for SSP. In fact what you
require is the phase locking of small (a few Kw) units.

- Ian Parker

It's always so much easier to figure when you don't have to be all-
inclusive, as in birth to grave worthy, or ever having to privately
pay for anything.

Since we're already $50+ trillions in debt, we might as well blow yet
another trillion worth of added global inflation.

~ Brad Guth Brad_Guth Brad.Guth BradGuth

On Aug 9, 4:51*pm, Ian Parker wrote:
I got 1000Kg basically by balancing probable lift capabilities. In
fact theoretically you need a lot less but 1000Kg is a fairly easy
figure to handle both from the balacing of lift and number of
elements.

That doesn't make any sense - I'm talking about factors related to
optics and the amount of power you need in the pilot or reference beam
to create a conjugate beam efficiently. In classical optics this is
related to the Rayleigh limit.

Phase conjugation. If wave equation is exp(ikx)

It follows that if we emit exp(-ikx) we will get reinforcement at the
source. Hence we have to take the complex conjugate.

Yep. This is done optically with 4-wave mixing. A hologram is made
with a reference beam and an image beam and you can use either to
create the other through diffraction. Same here except in a
nonlinear media the reference or pilot beam interferes with the image
or power beam, causing a portion of the power beamto be directed along
the path of thepilot beam but in the opposite direction. the rate at
which this happens depends on a number of factors, but this can be
exploited with variable pilot pulses to control the amount of energy
that gets directed to the receiver from the power source - all from
the reciever with no processing - save for the non linear material and
laser optics - on the satellite.

In the case of
microwaves this is fairly simple.

Yes, I've created a nonlinear microwave version of the very same setup
- no processing outside the nonlinear antennae array.

With light you STILL need sone
element of computation.

Its all done by the physics of waves.

You need to send a signal from some point to
your individual lasers and then compute the phase angle knowing the
phase angle introduced by your beat source.

Keeping the power beam and pilot beam in phase is the only trick you
need. That is achieved by looking at the phase of the power you're
getting back at the reciever and locking the pilot beam to that.
There is actually a quite simple dance that you can do between the two
beams - to quickly lock the pilot beam onto the power beam's phase.

Also you need to do a phase calculation for EACH laser diode.

4-wave mixing does that automatically - its like saying that sorting
is an np-difficult problem - and then having someone encode a bunch of
numbers as lengths of a spaghetti noodle, and then slamming them all
down at once on a table top and picking out the longest one
immediately.

Physics can do computations - waves - can do these computations rather
quickly - without a separate processor.

An
individual diode will only emit a few watts.

You're only looking at one aspect of the problem.

Start looking at the efficiency of sparse arrays of emitters - and
recievers - you will find that smart smoke has certain problems of
pilot beam gain, and even efficient transfer. That is, reduce your
particle size to 1/4 wavelength - that 'dot' emits over 4pi steradians
- isotropically into all directions - it can't do anything else - and
if you have other dots more than say 4 wavelengths away - that array
will reinforce only about 6% of the total energy it emits to the
Rayleigh limit based on your cloud size and if you have any optical
depth, you'll get Bragg's law effects -

of course a uniform optical media - a window - doesn't have these
effects to the same degree.

When you sit down and really do the math - considering a saturn's ring
of smoke like material - and you vary the particle size and separation
- you find that there are difficulties that come up that limit what
you can do.

Basically the size and
angular spread of an individual diode will depend on the total area
covered.

There are many effects. One is the size of the cloud. The cloud can
be big - and it can simulate an optical device that is that big - and
you can calculate the Rayleigh limit of that big cloud. No problem.
Get's pretty precise.

However, there are limits.

Each diode by itself will not be able to form spots on the Earth
below. They will be radiating over the entire Earth. It is only
when phase locked with other dots (how are you doing that?) that the
waves reinforce one another - but they only reinforce where they can.
So, a sparse array of dots, has a lot of phases unavailable, cause
those areas are empty in the sparse array. That means energy going in
certain directions doesn't get directed to the spot you want - leaving
that energy dispersed - so, in the example of the 1/4 wavelength sized
dots with 4 wavelength separation - you have 5% of the energy radiate
by the 'cloud' efficiently directed to the Rayleigh limit of the
cloud.

Do the calculation yourself you'll see.

If you have a thick cloud - you've got Bragg's law effects and your
beams start to have problems from that.

So, a 400 meter diameter window - made of thin film- is most efficient
above GEO.


This could be the size of a hemisphere of Earth giving quite
a large angle.

But if the elements themselves are too small to project spots as small
as your reciever, then you have a vanishingly small amount of light
from each spot fall on your receiver within the Airy disk of the
hemisphere sized cloud.

I think it iis important for everone to appreciate though that this is
very much a soft failing system,

Yeah the 95% that doesn't make it to the receiver is useless, and the
5% that does, goes away as elements go dark. Cool

and that this system is intrinsically
very safe.

So is my phase conjugate system - everything is controlled on the
ground. The laser beam disperses across the face of the Earth if no
pilot beams illuminate the emitting window. Pilot beam illuminates
the window and a power beam is formed. Do this pulse fashion taking
advantage of the formation characteristics to control return power.
Stand in front of the beam and you cut out the pilot beam and the beam
shuts off.

Thinking about it I like it as there is NEVER a danger of
out of control beams.

Right - any phase conjugate system - whether from a single window or a
dispersed window - has this same feature.

Rand is perfectly correct in supposing that you don't need to be at
GEO.

True. Phase conjugate techniques are used in laser cutters and
welders to maintain focus through clouds of sputter.

MEO is as good.

No its not when you consider the number of satellites you need to
maintain continuous power to receivers on the ground.

LEO is not really feasible as you can't operate
at night.

Utilization drops to 50% - night only lasts 42 minutes in LEO - this
is only half of 100% - MEO ranges from 45% to 35% loss - why is MEO
okay, but LEO not? Why is 45% not a deal breaker but 50% is? lol.
This obviously makes no sense.

GEO is where you put the big satellites and they are nearly stationary
above the hemisphere they serve. So, one satellite serves half the
world potentially. The phase conjugate beam forming window can send
power simultaneously to millions of receivers on the ground in
controlled amounts. Due to 1/4 second lapse times, the recievers
can't accelerate greatly - and still have the beam dwell on them.

MEO and LEO orbits make sense when you have high altitude satellites
beaming energy down - and you use a reforming satellite to bring your
phase conjugate window within 1/100th second of Earth - there you can
have beams efficiently directed as fast moving highly accelerated
objects.

That way since the MEO and LEO satellites are not collecting energy,
they can be used 100% of the time.

If you rely on conjugation you can have positions constantly
changing.

Yes, but remember that receiver and transmitter have to exchange
photons in order to remain locked - so,the power beam will lag the
motion of the receiver by whatever the delay time is. For GEO this
is 1/4 second. At 930 miles altitude, this is 1/100th second.

* - Ian Parker

On 10 Aug, 10:25, wrote:
On Aug 9, 4:51*pm, Ian Parker wrote:

I got 1000Kg basically by balancing probable lift capabilities. In
fact theoretically you need a lot less but 1000Kg is a fairly easy
figure to handle both from the balacing of lift and number of
elements.

That doesn't make any sense - I'm talking about factors related to
optics and the amount of power you need in the pilot or reference beam
to create a conjugate beam efficiently. * In classical optics this is
related to the Rayleigh limit.



Phase conjugation. If wave equation is exp(ikx)

It follows that if we emit exp(-ikx) we will get reinforcement at the
source. Hence we have to take the complex conjugate.

Yep. * This is done optically with 4-wave mixing. * A hologram is made
with a reference beam and an image beam and you can use either to
create the other through diffraction. * Same here except in a
nonlinear media the reference or pilot beam interferes with the image
or power beam, causing a portion of the power beamto be directed along
the path of thepilot beam but in the opposite direction. *the rate at
which this happens depends on a number of factors, but this can be
exploited with variable pilot pulses to control the amount of energy
that gets directed to the receiver from the power source - all from
the reciever with no processing - save for the non linear material and
laser optics - on the satellite.

In the case of
microwaves this is fairly simple.

Yes, I've created a nonlinear microwave version of the very same setup
- no processing outside the nonlinear antennae array.

With light you STILL need sone
element of computation.

Its all done by the physics of waves.

You need to send a signal from some point to
your individual lasers and then compute the phase angle knowing the
phase angle introduced by your beat source.

Keeping the power beam and pilot beam in phase is the only trick you
need. *That is achieved by looking at the phase of the power you're
getting back at the reciever and locking the pilot beam to that.
There is actually a quite simple dance that you can do between the two
beams - to quickly lock the pilot beam onto the power beam's phase.

Also you need to do a phase calculation for EACH laser diode.

4-wave mixing does that automatically - its like saying that sorting
is an np-difficult problem - and then having someone encode a bunch of
numbers as lengths of a spaghetti noodle, and then slamming them all
down at once on a table top and picking out the longest one
immediately.

Physics can do computations - waves - can do these computations rather
quickly - without a separate processor.

An
individual diode will only emit a few watts.

You're only looking at one aspect of the problem.

Start looking at the efficiency of sparse arrays of emitters - and
recievers - you will find that smart smoke has certain problems of
pilot beam gain, and even efficient transfer. *That is, reduce your
particle size to 1/4 wavelength - that 'dot' emits over 4pi steradians
- isotropically into all directions - it can't do anything else - and
if you have other dots more than say 4 wavelengths away - that array
will reinforce only about 6% of the total energy it emits to the
Rayleigh limit based on your cloud size and if you have any optical
depth, you'll get Bragg's law effects -

of course a uniform optical media - a window - doesn't have these
effects to the same degree.

When you sit down and really do the math - considering a saturn's ring
of smoke like material - and you vary the particle size and separation
- you find that there are difficulties that come up that limit what
you can do.

Basically the size and
angular spread of an individual diode will depend on the total area
covered.

There are many effects. *One is the size of the cloud. *The cloud can
be big - and it can simulate an optical device that is that big - and
you can calculate the Rayleigh limit of that big cloud. *No problem.
Get's pretty precise.

However, there are limits.

Each diode by itself will not be able to form spots on the Earth
below. *They will be radiating over the entire Earth. * It is only
when phase locked with other dots (how are you doing that?) that the
waves reinforce one another - but they only reinforce where they can.
So, a sparse array of dots, has a lot of phases unavailable, cause
those areas are empty in the sparse array. *That means energy going in
certain directions doesn't get directed to the spot you want - leaving
that energy dispersed - so, in the example of the 1/4 wavelength sized
dots with 4 wavelength separation - you have 5% of the energy radiate
by the 'cloud' efficiently directed to the Rayleigh limit of the
cloud.

Do the calculation yourself you'll see.

If you have a thick cloud - you've got Bragg's law effects and your
beams start to have problems from that.

So, a 400 meter diameter window - made of thin film- is most efficient
above GEO.

This could be the size of a hemisphere of Earth giving quite
a large angle.

But if the elements themselves are too small to project spots as small
as your reciever, then you have a vanishingly small amount of light
from each spot fall on your receiver within the Airy disk of the
hemisphere sized cloud.

I think it iis important for everone to appreciate though that this is
very much a soft failing system,

Yeah the 95% that doesn't make it to the receiver is useless, and the
5% that does, goes away as elements go dark. *Cool

and that this system is intrinsically
very safe.

So is my phase conjugate system - everything is controlled on the
ground. *The laser beam disperses across the face of the Earth if no
pilot beams illuminate the emitting window. * Pilot beam illuminates
the window and a power beam is formed. *Do this pulse fashion taking
advantage of the formation characteristics to control return power.
Stand in front of the beam and you cut out the pilot beam and the beam
shuts off.

Thinking about it I like it as there is NEVER a danger of
out of control beams.

Right - any phase conjugate system - whether from a single window or a
dispersed window - has this same feature.

Rand is perfectly correct in supposing that you don't need to be at
GEO.

True. *Phase conjugate techniques are used in laser cutters and
welders to maintain focus through clouds of sputter.

MEO is as good.

No its not when you consider the number of satellites you need to
maintain continuous power to receivers on the ground.

LEO is not really feasible as you can't operate
at night.

Utilization drops to 50% - night only lasts 42 minutes in LEO - this
is only half of 100% - MEO ranges from 45% to 35% loss - why is MEO
okay, but LEO not? *Why is 45% not a deal breaker but 50% is? *lol.
This obviously makes no sense.

GEO is where you put the big satellites and they are nearly stationary
above the hemisphere they serve. *So, one satellite serves half the
world potentially. *The phase conjugate beam forming window can send
power simultaneously to millions of receivers on the ground in
controlled amounts. *Due to 1/4 second lapse times, the recievers
can't accelerate greatly - and still have the beam dwell on them.

MEO and LEO orbits make sense when you have high altitude satellites
beaming energy down - and you use a reforming satellite to bring your
phase conjugate window within 1/100th second of Earth - there you can
have beams efficiently directed as fast moving highly accelerated
objects.

That way since the MEO and LEO satellites are not collecting energy,
they can be used 100% of the time.

If you rely on conjugation you can have positions constantly
changing.

Yes, but remember that receiver and transmitter have to exchange
photons in order to remain locked - so,the power beam will lag the
motion of the receiver by whatever the delay time is. * For GEO this
is 1/4 second. *At 930 miles altitude, this is 1/100th second.



* - Ian Parker- Hide quoted text -

- Show quoted text -

On 10 Aug, 10:25, wrote:

Yes, but remember that receiver and transmitter have to exchange
photons in order to remain locked - so,the power beam will lag the
motion of the receiver by whatever the delay time is. * For GEO this
is 1/4 second. *At 930 miles altitude, this is 1/100th second.

That is true. Having posted I was going to add that rider. You indeed
need to extrapolate 2d/c ahead. Thus a degree of computation is
unavoidable.

I read through the rest. The basic principle of an array in physical
optics is that your light intensity is a product of two things. It is
the envelope of a single element * The envelope provided by the array
viewed as point sources. Thus your individual element is going to have
a fair spread.

You are indeed correct in saying that you need equipment for detecting
the phase of the source. This is best done by having a unit which
consists of a camera with a Michaelson interferomer. An individual
subunit (consisting of a number of units) would have a resolution of
1km. Each pixel would represent about 1km on the ground and would by a
2000*2000.array. There are in fact 2 arrays, one on each arm of the
interferometer and we therefore have a 2000*2000 COMPLEX image. We
then multiply this image by exp(ip) where p is the phase angle of the
complete array. Of course we need to do our double journey
extrapolation. This equipment would not be large.

There is one point not so far discussed. The SSP lasers will produce
bright spots on the Earth. There is the problem of interference from
this light. Threre are a variety of solutions. One solution would be
to have the system pulsed. That is to say it pauses to allow the pilot
beams to be detected.


- Ian Parker

On 9 Aug, 23:35, Fred J. McCall wrote:
Ian Parker wrote:

:
:You are assuming that heavy lift is need for SSP. In fact what you
:require is the phase locking of small (a few Kw) units.
:

That may be what YOU require, but is anyone proposing building one
that way?

Why do I doubt it?

--
"Ignorance is preferable to error, and he is less remote from the
*truth who believes nothing than he who believes what is wrong."
* * * * * * * * * * * * * * * *-- Thomas Jefferson

Its the onlt logical way to do it. Having large parabolic mirrors at
GEO is totally impractical.


- Ian Parker

Ian Parker wrote:

:On 9 Aug, 23:35, Fred J. McCall wrote:
: Ian Parker wrote:
:
: :
: :You are assuming that heavy lift is need for SSP. In fact what you
: :require is the phase locking of small (a few Kw) units.
: :
:
: That may be what YOU require, but is anyone proposing building one
: that way?
:
: Why do I doubt it?
:
:
:Its the onlt logical way to do it. Having large parabolic mirrors at
:GEO is totally impractical.
:

Oh, is it? Why is that?

While you're at it, why do you need "large parabolic mirrors at GEO"
for SSP?

--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn

On 10 Aug, 11:50, Fred J. McCall wrote:
Ian Parker wrote:

:On 9 Aug, 23:35, Fred J. McCall wrote:
: Ian Parker wrote:
:
: :
: :You are assuming that heavy lift is need for SSP. In fact what you
: :require is the phase locking of small (a few Kw) units.
: :
:
: That may be what YOU require, but is anyone proposing building one
: that way?
:
: Why do I doubt it?
:
:
:Its the onlt logical way to do it. Having large parabolic mirrors at
:GEO is totally impractical.
:

Oh, is it? *Why is that?

While you're at it, why do you need "large parabolic mirrors at GEO"
for SSP?

--
"Some people get lost in thought because it's such unfamiliar
*territory."
* * * * * * * * * * * * * * * * * * * --G. Behn

There are 2 basic approaches to beaming energy. One is to have a large
fixed mirror. The other is a phase locked array. I am discussing phase
conjugation and it is very interesting. Instinct tells me that a large
fixed mirror cannot be the way forward.


- Ian Parker

On Aug 10, 6:20*am, Ian Parker wrote:
On 10 Aug, 10:25, wrote:

Yes, but remember that receiver and transmitter have to exchange
photons in order to remain locked - so,the power beam will lag the
motion of the receiver by whatever the delay time is. * For GEO this
is 1/4 second. *At 930 miles altitude, this is 1/100th second.

That is true. Having posted I was going to add that rider. You indeed
need to extrapolate 2d/c ahead. Thus a degree of computation is
unavoidable.

Best done photonically - with the photons themselves in a photonic
medium - whether microwave or optical.

I read through the rest. The basic principle of an array in physical
optics is that your light intensity is a product of two things. It is
the envelope of a single element * The envelope provided by the array
viewed as point sources. Thus your individual element is going to have
a fair spread.

Check on the physics of sparse arrays of elements. You can focus
within the Rayleigh criterion - but the efficiency with which you do
it goes to hell in a sparse array rather quickly - even if you
resolved all the other open issues.

You are indeed correct in saying that you need equipment for detecting
the phase of the source.

Which is achieved automatically by putting a phase conjugate mirror on
the backside of a laser cavity, and a phase conjugate window on the
front. You can get 1 million to 1 trillion power gain in such a
system

This is best done by having a unit which
consists of a camera with a Michaelson interferomer.

If all you want to do is detect. However the simplest thing to do is
to have a powerful laser equipped with nonlinear mirrors and front
window and illuminate it with a bandgap matched laser from far away.
The output of the laser will then direct itself immediately along the
pilot beam in the opposite direction.

The only computation is done by the designer of the control circuit.
Knowing the power laser's properties, we know how long it takes for
power to build up at the reciever, so power level is easily controlled
by controlling the duration of the pulse - then the rate of pulse
determines overall power.

An individual
subunit (consisting of a number of units) would have a resolution of
1km.

Your efficiency with a sparse array would be very very low -
furthermore - you have instant response with a nonlinear window - even
if constructed from microwave elements using linear op amps - and the
system is more reliable besides.

Each pixel would represent about 1km on the ground

Jesus - in tests from orbit we were able to get within a centimeter -
with a 400 m diameter window/mirror sandwich film powered by a 25 km
diameter inflatable concentrator - we should be able to do far better
than that even from GEO.

and would by a
2000*2000.array. There are in fact 2 arrays, one on each arm of the
interferometer and we therefore have a 2000*2000 COMPLEX image. We
then multiply this image by exp(ip) where p is the phase angle of the
complete array. Of course we need to do our double journey
extrapolation. This equipment would not be large.

I don't doubt you can do a calculation like that, but this makes
things far less certain than a DIRECT response to the photons as
they're travelling through the medium.

4-wave mixing - check it out dude.

http://en.wikipedia.org/wiki/Four-wave_mixing
http://www.physics.montana.edu/stude...s/FWMixing.pdf

See the picture of the cat on page 16 of the second paper - distotions
are removed. Check out the laser pumping description on page 5. You
can amplify weak signals.

Now, linear op amps can be wired into a diode array in such a way as
to implement nonlinear optics in microwaves - gains are more limited
and bandwidths are limited... but its a far superior process than
what you're talking about.

There is one point not so far discussed. The SSP lasers will produce
bright spots on the Earth.

Yes, at 1,100 nm - the bandgap energy of silicon, directed AT the
targets that request them if you use a continuous window/mirror thats
400 m across..

There is the problem of interference from
this light.

No there isn't. 1,100 nm is in the IR- at 400 Watts/m2 that's less
energy than is in the IR fromthe sun during the day.

Threre are a variety of solutions. One solution would be
to have the system pulsed.

I already use a pulsed system of power control.

That is to say it pauses to allow the pilot
beams to be detected.

The powersat sitting in GEO radiates its IR energy uniformly across
the face of the Earth. A receiver sends a pulsed bandgap matche beam
toward the satellite,trillions of times the energy comes back.
Controlling the duration and spacing of these pulses, power level is
highly controllable.

Stationary ground stations are assumed to be the early users of this
system. Mobile applications are assumed to require low flying
reforming satellites that have a nonlinear optical window at 930 km
altitude powered by GEO satellite,and controlled by terrestrial users
- either mobile or stationary.

A minimum of 3 power sats generating a total of 600 GW in conjunction
with 660 low flying reforming satellites - have the capacity to
deliver power to anyone anywhere on Earth including mobile users - for
about 1/5th cent per kWh - that's $3.39 per barrel of oil equivalent.

A vehicle covered with a propulsive skin, consisting of an array of
tiny rockets, powered by laser beams from space - creates a new sort
of vehicle - that is safe reliable quiet - and quite capable of
providing personal ballistic transport.

Millions of these vehicles - powered by the satellite system described
- would transform the airline and transportation industries. Small
package delivery vehicles would occur in even greater numbers.

Operating in conjunction with satellite broadband,folks would call for
a vehicle by texting their destination into the system - common
destinations would be stored in memory - very similar to finding a
spot on Earth via Google Earth.

The person's cell phone account would be billed and a vehicle would
appear in seconds - accurately positioned by space based GPS.

Users get in and are transported within minutes to their destination -
costs range from $5 to $15 per trip- depending on range - for up to 4
passengers. The longest trip would take 50 minutes and deliver you to
the antipodes. You could travel anywhere in North America in less
than 5 minutes for $5. Heavy users can buy monthly unlimited use
contracts for $300 per month or so..
. ..
Allowing 20 flights per hour per vehicle - and 10 hours per day of use
- each vehicle is engaged 200x per day. With an average loading of
1.5 people per trip,that's 300 people per day. So, for the USA's 300
million people using this 6x per day, we have 6 million vehicles
needed to serve North America. If all 150 million American drivers
pay $300 per month This system earns $540 billion per year -
significantly more than making and selling fuels.

120 million vehicles serve Earth - and all of the world's 800 million
drivers pay $300 per month - that's $2.88 trillion - 2/3 of what every
pays for fuels. We could even have family plans that let kids go to
school and moms go to the store.

You would live anywhere and work anywhere else, and buy and sell
anywhere.

The Earth will be far richer as a result.
.
* - Ian Parker