Re: Modest Proposal - Common Interplanetary Booster

Isp improvements on orbit translate to larger launcher sizes. That
is, the money you spend on building ion rockets, is really a
substitute for larger launcher sizes. Since launchers are too small
anyway, for powersat and factorysat and asteroidal capture, the first
step is clear. And once you have a lever, you use it - without
waiting around for efficiency improvements, though you do those too.

To go from LEO to GEO we can figure out from the vis-viva equation;

v^2 = mu*(2/a - 1/r)

To kick a payload from LEO to GEO requires adding 2.47 km/sec to the
payload. Then, when you're at altitude, you have to add another 1.47
km/sec. Then, to recover the booster, you have to subtract 1.5 km/sec
- to re-enter. Total delta vee is 5.44 km/sec.

Most of the payload is deposited at GEO.

Start with 2 million pounds at GEO and look at two different
conditions;

1) chemical kick stage with 4.5 km/sec exhaust speed
2) ion kick stage with 45 km/sec exhaust speed.

The structural fraction of the chemical kick stage is 12.5%. The
structural fraction of the ion kick stage is 37.5% - only 3x the
figure of the chemical rocket.

So, the chemical rocket needs;58.3% propellant fraction to accelerate
its payload to 3.94 km/sec. This leaves 29.2% for payload. Around
584,000 pounds the 600,000 pounds I mentioned.

Now you've got to recover the 250,000 lb stage - there's actually
two in this scenario, and one falls back immediately, while the other
has to be deorbited. Still, we have to subtract 1.5 km/sec - and with
a 4.5 km/sec rocket We need 28.4% the empty mass - which is 70,800
lbs for the larger mass,and 35,400 lbs for the smaller mass - this
reduces the payload at GEO from 584,000 pounds to 429,200 pounds in
the first instance, and 550,000 pounds in the second instance.

So, we have a 29 million pound launcher putting up 550,000 pounds into
GEO - with an all chemical booster -

Now, we have a 45 km/sec ion rocket achieving the same thing - with a
37.5% structural fraction. That's 650,000 pounds of structure.

We have the same 2 milion lbs on LEO. The same delta vees to carry
out. 3.94 km/sec - requires

u = 1 - 1/exp(3.94/45) = 8.4% propellant on the boost up.

This is 167,700 pounds of propellant on a 2 million pound starting
mass. Adding this to the structural fraction, we have 817,700 pounds
of stage and propellant, leaving 1,183,000 pounds of payload. About
double the payload. We have to figure out the deorbit propellant now.

The 650,000 pound stage has to deorbit so, it must go through a delta
vee of 1.5 km/sec. That means 22,000 pounds of propellant are
needed. This reduces the payload on GEO to 1,161,000 pounds.


CHEMICAL ION
4.5 km/sec 45.0 km/sec
459 sec Isp 4590 sec Is
2,000,000 stage 2,000,000 stage
250,000 structure 650,000 structure
1,150,000 propellant 189,700 propellant
550,000 payload 1,161,000 payload

We've more than doubled the payload FOR THIS LAUNCHER by adding a
higher performing upper stage. The question we mst always ask, is the
complexity and cost of adding this sort of technology to the upper
stage worth the improved performance? That is, if we take the dollars
and time to build a larger launcher, would we be ahead?

The answer I get is yes - using money at this juncture to build larger
launchers and launch them from adequately maintained launch centers at
appropriate locations at cost effective launch rates - is the quickest
easiest way to imrprove our capabilities in space. Once we've maxed
that out, we can start talking about improved propulsion - on existing
airframes and so forth.

I have already mentioned elsewhere, on the very large launcher posts I
made a few weeks ago, that laser powered propulsion units are logical
next steps once the laser powersats are installed and excess power is
available at reasonable costs.

This is not the case today since we're suffering from high energy
prices a shortage of supply and increasing demand. Once this is
usefully addressed with the program described here, then it makes
sense to invest in some form of laser/ion propulsion - done at a power
level and at a structural fraction that beats the pants off of
conventional ion propulsion touted here.

Obviously, I'm looking at this as a business proposition.

Step 1: Create ultra-low-cost terrestrial solar panels.

I've done this.

http://www.usoal.com

and here's how you use them

http://www.ohiochamber.com/governmental/pdfs/William%20Mook_021308.pdf

Make hydrogen from solar DC and burn hydrogen in coal fired plants to
make AC on demand. Then take the coal not burned combine it with more
hydrogen to make liquid fuel products.

This supplies all our oil needs worldwide, and cuts our carbon use
more than half. This is sufficient to reverse the trend in carbon
build up since nature does have some capacity to absorb carbon in the
carbon cycle.

Step 2: Buy space launch assets from major aerospace firms.

Once this is in place, use the revenues to buy the space launch assets
of the major aerospace companies throughout the world. Those are
reorganize to build up space launch abilities. With this kind of
money I joint venture with other publicly owned business-like
entitites.

Step 3: Build subscale fully reusable commercial launcher.
Basically, I propose the Comon Interplanetary Booster and offer
contracts to help build and operate it - while reserving use for
powersat experimentatoin.

Take a small portion of the nearly $4 trillion earned in fuel and
electricity sales, and invest it in a large heavy lift launcher -
first a 500 ton to orbit. This is described here - and later, when
SSP technology is proven out - a larger 10,000 ton to orbit heavy lift
vehicle. Translating of course the ability to loft 10,000 tons into
25 million pounds of payload on Mars.

Step 4: Deploy a global wireless internet satellite constellation.

Orbiting 660 satellites in 33 sun-synch oribts of 20 satellites each -
each satellite massing 20 tons - provide 50 billion channels of
wireless broadband throughout the world, and capture $300 billion in
communications revenue and trillions of dollars per year in online
banking, financial services, and insurance revenues.

Step 5. Develop and deploy new powersat technology

Using revenues from space based assets, invest in developing new space
based assets, principally powersats. Do this in conjunction with
privately funded exploration along the lines described here, using the
same launcher set, with custom built flight elements to carry out Mars
expeditions, lunar development, and exploration, and asteroidal
exploration and development.

Step 6. Once powersat technology is proven, build larger launchers.

Using a portion of synfuels revenue, build larger launchers along the
lines described elsewhere, capable of putting up 10,000 tons (200
million pounds) into LEO with 12 million pounds (6,000 tons) into GEO
and 5,000,000 pounds (2,500 tons) to the surface of the moon and mars
and the Near Earth Asteroids.

Step 7. Once large powersats are operating on orbit, upgrade upper
stages to use high specific impulse laser propulsion and laser light
sail technology. Use this to harvest asteroids - and double payloads
from Earth to high orbit - and triple payloads to Mars and the Moon
and the asteroids from Earth.

Terrestrial solar power systems that are providing hydrogen for
massive synfuel production have their output increased 16x with the
addition of bandgap matched lasers on orbit - increased energy
translates directly to 16x the energy from hydrogen. As the
hydrocarbon fuels max out - additional demand is fulfilled with
hydrogen fuels.

Step 8. Develop MEMs based laser powered propulsive skin spacecraft
to implement personal ballistic transport on Earth and beyond Earth.

As the ability to absorb increasing amounts of power become bound by
our ability to ship and handle increasing amounts of hydrogen, direct
beaming of laser energy to end users begins. One of the central
consuming sectors is personal ballistic transport. Moving from a
pedestriatn socieety to an automotive society increases energy use
rate by 11x. Increasing from an automotible society to a personal jet
increases use rate by another factor of 9 - 100x more than
pedestrian. Increasing from aircraft to ballistic spacecraft
increases demand for energy another factor 30 - 3,000x pedestrian.
We have sufficient power on orbit if we beam energy directly to users
on demand.

As the cost of power and energy decreases, the cost of handling fuels
comes to dominate the cost - particularly if the fuels are high
pressure gases, or cryogenic fuels. So, when the handling costs
dominate, direct beaming will be preferred.

Instituting a Moore type curve in reucing the cost of energy and power
- from space - we can even predict when these sea changes come about.
When everyone can afford cars, airplanes, and spaceships - and when
they move from hydrocarbon,to hydrogen, to direct beaming.




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Relevant Pages

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  • Re: Modest Proposal - Common Interplanetary Booster
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