Re: Super-heavy lift reusable launcher

On Aug 9, 12:03 pm, Ian Parker <ianpark...@xxxxxxxxx> wrote:
On 9 Aug, 12:33, Willie.Moo...@xxxxxxxxx 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.

Not when you look at lowest system cost.   There are cost differences
when scale changes.   While it is feasible to build on the scale you
speak of, it is not AS cost effective.   Demonstration projects using
subscale systems - will certainly be built as you suggest.

I am not talking about a sub scale system.

I know.

Phase linking produces a
full size system.

Yes. The question then is, what is the optimal size per module?

There is one other point too. The system must be
engineered to fail soft.

Yes.

This means that we need to divide up both
solar power and computer power.

You understand about phase linking. Do you understand conjugate wave
formation and wave mixing? Nonlinear optics? In my system a pilot
beam arrives from a receiver demanding power. That beam arrives at
the laser window and creates a nonlinear optical effect. This mixes
with the power laser beam and a portion of it is directed precisely
along matched to the conjugate of the phase of the incoming beam.
This means its phase locked to the weaker pilot beam, but travelling
in the opposite direction. So, even if the pilot beam is distorted -
the power beam is predistorted at its source, to arrive at the
receiver - undistorted. If the pilot beam is interrupted for any
reason, the power beam is cut off. If the pilot beam moves, the power
beam follows.

Please note there is no electronic computing or software involved at
this point. Its all a matter of optics.

So, given this system, what we're really talking about is the optimal
window size to fabricate and launch using current technology.

The Internet is composed of a lot of
small units.

Yes, so is the nonlinear window that works with the nonlinear
reflector within the power laser's fabry-perot cell to generate
powerful and controlled conjugate beams in response to weak pilot
beams.

The Internet has never failed even if individual units
have.

Same here- except on the atomic level. Light impacts the medium by
changing its refractive index. The changing refractive index changes
the path of light. These two operate together - along with the lasing
cavity optics and the receiver optics - to create a fail safe system.

The optimal size for a transportation system is far from being clear
cut.

Until you design a representative system - such as the one I've
described.

Weight goes up as L^3 whereas strength goes up only as L^2. Large
units go better through the lower atmosphere, bur small units reenter
better.

This is one of many factors. The ability to fold thin films factors
into this.

I think we need to concentrate on $/Kg at LEO and on building an ion
drive from LEO to GEO. Plus of course material from space.

Yes. When you do that you find - what every other rocket scientist
has found since the beginning of rocket science;

1) make the launch system reusable
2) increase the flight rate
3) increase the vehicle size

That's why the Army, then the Air Force, then NASA, were building 1.5
million pound thrust engines on test stands back in 1959. The F1 and
the M1. NASA inherited this work, and built the Saturn V around it.

They were originally validating the scalaing laws for rocket engines -
to see where they might go in the future. Those early studies suggest
100 million pound thrust engines are nearly optimal for interplanetary
space operations done on a large scale.

The size I propose here is nearly optimal to transition from chemical
launcher, to chemical/laser launcher,

Yes. I spoke with a few people about Laser Sustain Detonation
launchers a few decades ago - and others about rail gun launchers. It
makes an interesting system. On one end you have systems that are the
size of dust motes - smart smoke one researcher called them. On the
otheryou have systems that are the size of planets - these are the
optical systems proposed by Bob Forward to beam energy to interstellar
vehicles tens of light years away.

Now, what's optimal depends on the details of how you do things. In
any system that's never been done there are open issues - and
estimates of the level of work required to resolve them - and the
probability of success. Smart smoke level systems - the size of ICs
or smaller - have distinct problems in maintaining phase lock across
large populations - they're likely solvable but they're not
resolved. They're a barrier to getting the job done. But, if you
can build them, and operate them efficiently - yeah - you can use
steam cannons, rail guns or laser launch capacity to fire them off
like machine gun bullets into orbit. Are they the lowest cost way to
go? Well, you can do it more cheaply than rockets today - AT A
CERTAIN SCALE - WHEN THE PROBLEMS ARE RESOLVED. Until then, they're
fantasy. But after - they're competitive in certain conditions. I
can imagine a family having a packaged smart smoke dispenser aboard
their space station that they land on a new world and deploy it.
There are even designs I've studied that involve tiny wing shaped
solar panels forming rotors - and two counter-rotating-rotors produce
lift. Since the weight scales as the cube of dimension and the
collector area scales as the square of dimension - smaller systems
tend to have higher power to weight. So something the size of
bumblebees can fly freely through the air and hav spare power to beam
to a central collector. They all fly back to power center at the end
of the day, to resume flight in the morning. You can even dispense
with the MEMs based lasers and replace them with MEMS or nanoscale
chemical processing centers, so the free flying solar aircraft
accumulate fuel during daylight hours and dump it in a hopper at
sunset. These are all possible, but they all have open issues that
need to be resolved in order to be practical. The non-recurring level
of effort impacts their value today. Iam certain given their
advantages, they will one day be an important aspect to a solar power
economy, but they will not lead the way, or be central on Earth -
though they may be very important on the development of Mars or the
Moon - or free flying colonies - in the future.

Alright, now, we look at minature stuff - the size of ICs to Coffee
Cups or bread baskets. These things have a different launch cost -
and are most easily adapted to today's rockets. Especially using MIRV
type technology - a nice little bus to hold all the pieces in place
during ascent. This is one of the most costlyways to go.

Now, as you get larger, something the size of automobiles or bigger -
you can't use today's launchers easily, so you've got to start
thinking about BIG launchers. The bigger you go, the problems of the
smart smoke phase control go away. Lots of problems that the smaller
systems go away - to be replaced by the bigger systems. Here,you have
large collector areas, but in order to reduce costs, you have thin
films - and fold those filmsinto compact forms the size required.

When you start looking at chemical rockets - the kind we can build
today - and start asking questions about what's the optimal size -
then you are led inevitably to building bigger ships. Why do you
think there is a push to build bigger sea going vessels? bigger
airplanes? The efficiencies of scale. That's why you have 400,000
ton tanker ships that are nearly half a kilometer long plying the
seas. That is also why the cheapest way to loft things off-world will
be big ass rockets. Now there will be rail guns and laser launchers
firing pellets into space at a rapid rate - just like there are
pipelines and slurry lines - next to highways - but of all the things
we have to build - we have to ask, what do we build first to get the
biggest bang for the buck, and establish a dominant market position?

The answer is, 1.5 million ton launchers lofting 10,000 tons ot GEO
which is sufficient to loft a 200 GW powersat.

and deep space laser probes, and
laser recovery of asteroidal feedstock.

haha..  even at 200 GW per satellite - which is broken down using
conjugate optics into many many beams some as small as 10 kW - you
still have to combine 100s of satellites to do heavy lifting with
laser energy - so 200 GW satellite size WILL also operate in phase
locked mode - sharing a common pilot beam from a common receiver to
usefully combine energies to do heavy lifting.

As I said $/Kg not Kg at one go.

Right. And $/kg is the driving factor. Similarly its $/kg not $ per
launch.

You need to ask the cost of the TOTAL
weight.

Yes.

Can the weight be reduced by contributions from space?

That cannot be done until an infrastructure is established and the
weight of that infrastructure is known -

I am
not convinced you need more than 1000Kg at one go.

Why? I agree with that, and I have solid scaling calcualtions to
prove it. But what convinced you? You seem to be unaware of these
sorts of things, so I'm curious.

What's interesting is if you look at the consumption curve of each
person throughout the day and by season at each latititude in an
industrial society, and then you shift that curve by longitude and
latitutde for each person - and then sumall the component curves - to
get a global energy demand curve - you end up with something like 210
TW average power - which peaks at over 300 TW and drops to less than
100 TW - throughout the day.     This means there will be 1,500
satellites of this size!!  So, they'll certainly operate in a variety
of modes - including combining their outputs for space workmostly.
Harvesting asteroids, sending out space probes, sending out
interstellar probes, and so forth.

If you choose a laser you can in fact supplement terrestrial
photovoltaics from space.

Yes, if you can accurately beam laser energy to the photovoltaics
without loss. or with minimal loss. The pilot beam/power beam trick
achieves this - but there is an optimal area for that as well - with
today's optics. With tomorrows optics assuming certain advances -
receivers will get smaller, intensities higher - optimal window sizes
will fall - direct beaming to end users will be possible. All these
things will happen - but not at first.

This is quite interestin. I think you wil
find that peak demand tends to be daylight hours.

yes - for each latitude. What time of day is it where you live when
the entire earth's power demand is lowest? When it is highest?
There is such a time for each of us. Do you know what it is?
That's what I'm talking about.

Space would be very
useful in the early evening.


Laser energy generated anywhere in GEO can find its way to any point
on Earth when needed. When its early evening in Hawaii, its early
morning in India, and midnight in New York, and Noon in Sydney.

What I'm talking about is the total demand for the entire Earth and
how that varies. This is a function of distribution of population
across the Earth.

This means that there are certain times of the day that you'll have
the 33 TW available for launch for 10 minutes or so at a time.  You'll
be limited to launching fewer than 6 vehicles per day - once your
system is fully use and integrated into the world's economy.

Ultimately - 100 or so of the 200 GW satellites will be permanently
dedicate to supporting space operations.- Hide quoted text -

  - Ian Parker

I think we're talking past each other in many ways. I have looked at
small systems and once certain open issues are resolved they have
great potential. ITs not something we can do easily today. Larger
satellites built around inflatable optics - are far easier and cheaper
to do - and have the least time to revenue and the lowest cost ot
revenue, while ;providing very little room for competitors to do a
technological end run around you while building a powerful barrier to
entry in a variety of ways.

.

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