Re: Fusion Rocket to the Moon
- From: Willie.Mookie@xxxxxxxxx
- Date: 1 Mar 2007 18:54:08 -0800
http://www.columbia.edu/~ig249/V1003-IanG/web-pages/Page%203.htm
According to some experts the sea-levels are rising and are likely to
rise faster in the future. There are two causes. One is the
expansion of water as the average temperature rises. Two is the
decrease in glacial mass worldwide, which shows up in the oceans.
Melting glaciers added 6,000 cubic kilometers of water to the world's
oceans. Expansion of seawater due to rising temps added 84,400 cubic
kilometers of water to the world's oceans a total volume change of
90,400 cubic kilometers.
Some experts believe that the polar caps will melt eventually due to
rising green house gases and flow into the ocean over the course of
time. This will add 28,928,000 cubic kilometers of sea water. This
has happened in the past on Earth in as little as 500 years.
Removing this water to the moon terraforms the moon as well as
maintains sea levels on Earth at their current levels.
Today's Excess: 90,400 km3
Tomorrow's Excess 28,928,000 km3
Taking this volume and dividing it across the moon's surface of 37.93
million km we obtain a depth of water as;
Moon Depth: today: 2.38 meters
Moon Depth: tomorrow 762 meters
Removing excess water volume on Earth to the moon would stabilize the
Earth's oceans and provide additional habitable area for humans. The
smaller volumes would be contained in pressure vessels spread
throughout the moon. Larger volumes would be free across the surface
of the Moon with an all encompassing atmosphere.
Water and nitrogen and oxygen can also be imported from icy comets and
asteroids as well.
Earth's atmosphere masses 5.14e18 kg and Earth's area is 510.07
million sq km. This is about 1e10 kg per sq km. 78% is Nitrogen, 21%
is oxygen with other gases thrown in to make up the total. The Moon
is 37.93 million sq km, so the mass of the Moon's atmosphere at this
density is 3.8e17 kg.
Now, this much gas on the surface of the moon wouldn't exert the same
pressure as on Earth. Why? Lower gravity. The lapse rate would be
far higher as well. That is, the pressure would be lower on the
surface and higher as you go up than the same altitudes on Earth. The
Moon's atmosphere would be much thicker. It would also esape over
millions of years, and the outgassing would affect orbits over that
time period as well.
Even so, in terms of human history, a lunar atmosphere and ocean would
last longer than humans have been around on this planet. Losses can
be replaced as well, using icy comets and asteroids.
The problem with pressure can be addressed several ways. One is to
encompass the moon in a large pressure vessel, another is to change
the composition to get partial pressures of most gases in the range we
want. Reducing nitrogen for example to nearly nothing, while being
almost pure oxygen, at lower pressures. Since organisms need nitrogen
this likely isn't a good solution. Another is to increase the total
mass of the atmospere 5 times 1.9e18 kg to nearly half that of the
Earth. In fact, due to varying lapse rates larger planets need less
air to maintain pressure, smaller planets need more air. So, air mass
tends to group around 1 earth air mass for a wide range of planets. A
rule of thumb for future terraforming engineers.
I detailed elsewhere how a constant gee (Local + 1/6 gee) boost from
Earth to moon can transfer these sorts of masses in decades. This can
be liquified air as well as parts of Earth's oceans. Similar
calculations show that asteroids and cometary material (like Sedna)
can be moved as well. The moon's orbit itself can be changed.
The energetics of thermonuclear fusion permit this, provided large
numbers of large vehicles can be created. We aleady see how large
numbers of automobiles can be built using 1920s technology and used to
change the Earth's environment. In future more advanced technologies
can be designed to counter unintended side effects and restore
environmental balance, and more importantly transform any world into a
habitable world.
While many might say this approach to building environments is
wasteful of material and short lived, I would reply that there is
plenty of material in the cosmos and the alternative to living in a
gravity well, that is livig in a free flying pressure vessel, while
efficent in use of materials, is not a well proven technology. Cosmic
rays, collisions, the length of time the systems on the pressure
vessel will reliably operate, are all unknowns at present. These
systems should be built, and will be built, but they will form only a
single avenue of development with terraforming places like the moon
and mars, forming another avenue.
Three developments in the coming technological convergence that will
lead to a singularity in human history will allow humanity to achieve
nearly anything that's physically possible to achieve in the solar
system. The three developments, expected to be perfected in the next
35 years are;
1) Hot desktop fusion;
2) Self replicating machine systems
3) Strong artificial intelligence (super human)
I detailed elsewhere where it will be possible with these three
technical developments to create a single seed programmed to self
replicate on the ocean's floor using hydrogen in seawater for fusion
power, and materials found on the ocean floor to build copies of
themselves, guided by strong AI.
In the end millions of supertanker sized fusion powered spaceships
emerge from the ocean's depths and carry excess water to the moon and
some air, distributing it strategically across the surface. The moon
itself is processed for additional water and air components while the
lunar regolith is reworked to support life. The fleet of fusion
powered ships departs from cislunar space to retrieve needed materials
from around the solar system, to put the finishing touches on the
revised moon, and leave in place a solar powered transport and
industrial infrastructure that supports personal rapid transit
between Earth and Moon, as well as maintain idealized conditions on
both bodies, while maintainint the human race at very high living
standards besides.
37.93 million sq km of new land that the moon represents when built up
to a very high standard supports 8 billion people - with an average
family of 4.1 is 20,000 sq m per household. A hexagon 80 meters (262
ft) across.
With 1 day replication times for elements, and starting out with a 1
kg seed, planetary masses can be transformed on the order of months.
Example: 3e19 kg - mass to be processed.
1e00 kg - mass of seed
Periods = LN(3e19/1e00) / LN(2) = 64.7
Doubling times, 24 hours - this is 64.7 days - a little more than two
months.
Creating and programming the 1 kg seed will take the most time, and
modelling its operation. But strong AI can help with this. In fact
strong AI is likely the enabling event for the other processes. Self
replication gives us the volume, and fusion gives us the power.
I envision a world where our present issues of poverty, need, resource
depletion, environmental degradation, are easily resolved. I envision
a world where people travel as easily between Earth and Moon as they
travel cross country by automobile.
Check it out;
Moon Distance: 4e8 m
Halfway: 2e8m
1 gee = 9.82 m/s/s
D = 1/2 a t^2
2e8 m = 1/2 * 9.82 * t^2
Solving for t
t = SQRT(2e8 / (1/2 * 9.82) ) = 6,382 seconds --> 1.77 hours
This is to the halfway point. So it would take double that time or
3-1/2 hours to fly to the moon at 1 gee. This is the length of time
of a cross country car trip or a jet ride to a nearby city. It is
within possiblity that given a broad ownership of automobile sized
fusion powered ships that people could commute between Earth and moon
daily.
The velocity of these ships at halfway would be
V = a * t = 9.82 * 6,382 = 62.67 km/sec
Double this again to get the total delta vee, since this speed must be
cancelled. 125 km/sec. With exhaust speeds of 20,000 km/sec possible
with antimatter catalyzed fusion - propellant masses of;
u = 1- EXP(1/(Vf/Ve)) = 1 - EXP(1/(125/20000)) = 0.62%
So, a 1,000 kg vehicle would carry about 6 kg of propellant - about
the mass of two gallons of gas.
A world encircled by a Saturn like ring of small bodies supporting
massive industry off-world, supplying for every need and want across
the two planets. Earth will be preserved in its current state for the
long term. With the exception of historically important locations on
Earth, and vacation sites people will live in large pressure vessels
on orbit around Earth near industrial processing centers, or on the
terraformed surface of the moon.
Mars too will be teraformed and have its own industrial ring
surrounding it. Venus and Mecury with greater effort can be
teffraformed as well. In all, a surface area 3x that of Earth today
will be transformed to human use by the end fo the 21st century. 20x
the surface area of Earth will be formed as well by pressure vessels
made at far less cost of material energy and effort.
.
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