The Future Of Canal Transport–Take The Elevated 3: Flat-Boatmen Of The Lunar Frontier: 7 Uses For Lunar Sodium

In this third and final part of the series we briefly recap the specs of the elevated canal project that got
 me to thinking about the uses of such elevated canals

The Magdeburg  Canal Bridge in Germany might technically be called a navigable aquaduct but it differs
 in both feel and practicality from earlier efforts. Compare the smaller ones shown on this web page

with the Magdeburg water bridge and you will be comparing a toy tool with a professional power tool.

Germany: The Magdeburg Water Bridge – Wasserstraßenkreuz Magdeburg

Facts about Magdeburg  Canal Bridge
  • six years to build
  • cost of 500 million Euros
  • 918 meters long
  • 545000 Euros per meter
  • Width   34 m
  • Water depth     4.25 m
  • Longest span    106 m
  • Total length       918 m (690 m over land and 228 m over water)
  • Clearance below           90.00 m x 6.25 m
  • 68,000 cubic meters of concrete and 24,000 metric tons of steel
  • Connects Hannover and Berlin directly
  • Connects Berlin’s inland harbor network and Rhine river ports.
When looking at the Moon in a telescope, despite the name ‘maria’ applied to the lunar seas, 

the astronomy buff knows that it is bone dry. If there is one world in the solar system 
that you would  think boating would be impossible on it would be the Moon.
When the Moon was thought to have deep seas of dust, Arthur Clarke wrote a story 
about a boat that could float on the dust that would engulf ordinary spacecraft, of
 course since the Surveyor missions we have known that there are no 
lunar dust pockets like quicksand waiting to 
engulf the luckless astronaut–
But that also means we are going to have to look elsewhere to float our lunar boat.
Lets look at what the Moon is made of–
Chemical composition of the lunar surface regolith (derived from crustal rocks)

Compound Formula Composition (wt %)
Maria Highlands
silica SiO2 45.4% 45.5%
alumina Al2O3 14.9% 24.0%
lime CaO 11.8% 15.9%
iron(II) oxide FeO 14.1% 5.9%
magnesia MgO 9.2% 7.5%
titanium dioxide TiO2 3.9% 0.6%
sodium oxide Na2O 0.6% 0.6%
Total 99.9% 100.0%
Sodium has a weight of 23, oxygen 16 so thats 46+16
 or 62 divided by 46 or about 74% sodium.
So, .6 percent sodium oxide x .74 percent sodium
means lunar crust material is about
0.444 percent sodium. or 1 part in 225.
For every gigaton of lunar crust we can produce
4.44 megatons of sodium metal
which is liquid between the temperatues of  98 and 882  °C 
and   and has a density of  .927
when liquid so it
would float on water if you could avoid the
exploding on contact thing.

That one inconvenient fact
probably has cut short a  number of  Earthly sodium based
 naval careers short right there.
As it happens a waterfall of sodium hitting actual water
would look something
like the Fire Falls on Krypton. Hit splatter ***BLADOOM ***
AND EACH PIECE of debris REPEATS the cycle
This is just a few tons of sodium. Don’t try it with a million tons.  Word.

Melting point 370.944 K ​(97.794 °C, ​208.029 °F)
Boiling point 1156.090 K ​(882.940 °C, ​1621.292 °F)
Density near r.t. 0.968 g/cm3
when liquid, at m.p. 0.927 g/cm3

Understandably, Lunar colonization advocates have thought of the more
glamorous lunar substances like titanium or aluminum or iron. Lunar sodium

Na (Sodium).jpg

 is often
neglected because on Earth it is hideously dangerous
 to handle in any kind of environment
where it can contact water: Which is to say even in deserts.
 When we colonize the Moon we need to not let
Even wise habits born on Earth constrain our thinking.

Notice the wise safety precautions show in these videos.  

On Earth melting and handling sodium can be hideously dangerous-
on the Moon keeping it shiny and clean should be much easier.

So what do we do for a liquid pathway to float our dreams 
of easy lunar transport of heavy cargoes?

How about elevated lunar canals of liquid sodium?

Obviously this requires the kind of huge industrial Lunar
 infrastructure I have written of before,
such as  Linkage to the last article The logistics of huge 
surface processing.

But once that is achieved—Flatboats of the Lunar Frontier! 
 We need to have guys in bubble helmets and spacesuits 

poling their barges along elevated open canals of liquid sodium suspended on pillars. 
On the other hand the waste oxygen and cooling water in their suit exhaust might
 tarnish the sodium river so forget that.

Flatboatmen of the Frontier (1941)

Presents a phase of pioneer agricultural economy in the early nineteenth century.
 Portrays Ohio Valley farmers as they fell trees, prepare the lumber, and
 build a flatboat to carry their produce down the river to market.

This movie is part of the collection: Prelinger Archives

OK I’ll settle for Lunar sprocket locomotives pulling barges
 along the endless silvery sodium canal lines or maybe
 solar powered paddlewheel tugs.

I don’t want to hear the phrase “Lunar Riverboat Gambler.”
  Are we clear on that part? Good.

This is a map of the lunar surface– 
note the 13 km spread between highest and lowest.
“MoonTopoLOLA” by Mark A. Wieczorek – Own work. Licensed under CC BY 3.0 via Commons –
 That is the equivalent of an Earth gravity elevation  of around 2.1  km well within the strength 
of limits material limits of iron so elevated iron canals holding liquid sodium will
 work if solar heated when needed (or heated by stored solar heat)
 and shaded when cooling is required, leveled and filled with Sodium. 
The vision is of 

a pair of 50 meter wide elevated canals in a 30000 km network
 making it easy to sail (OK motor) 
from pole to equator ignoring terrain roughness.
(if 10 meters deep 1000 cubic meters of sodium per linear meter of canal, 1 million tons or so
 a kilometer, if 30000 km of canals 30 billion tons of sodium requiring mining of about
7 trillion tons of Moon rock– something more than the mass of Phobos–)

The cool part about this is that even in vacuum there is a certain amount 
of natural evaporation of even very high vaporizing materials just by the nature 
of vapor pressure in vacuum. (Other than near absolute zero)
This is why the 1940s thought that some asteroids were contraterrene matter
 (anti-matter) like in the classic works SEETEE SHIP
and SEETEE SHOCK (by Jack Williamson) would
 actually have been quite conspicuous. 
The (then unknown)  solar wind would encounter the vapor pressure 
if not the actual surface
 and there would be gamma rays.
The upshot of this is that the Lunar canals will start to look like Martian like canals 
not in color but in the fact that their linear point to point nature
 will have not merely say a pair of 50 meter wide elevated canals 
but the sodium metal evaporate from vapor pressure will SHINE
 along the canal path at full Moon night  on Earth,
 coating the regolith for at least kilometers either side over much time.

Sodium vapor pressure 

P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 554 617 697 802 946 1153

Note that of course typical temperatures in a shaded lunar canal way will be lower, 
nonetheless over time–

 As the sodium vapor escapes it will condense outside the canal and 
basically coat the lunar surface for kilometers on either side.  
Over many lunations, definite lines will emerge connecting canal nodes–
thus making our moon resemble–

 the pre-1965 picture of Mars as sketched by Percival Lowell!

Other uses for lunar sodium

NaK alloy has been used in Soviet space reactors 
but on Earth is quite dangerous

liquid sodium will also work straight in a lunar environment as a boiler fluid.
air lock
mirror (as we saw above)
easy machining soft metal which can be used for lost sodium casting

The final canal network is of course fun to imagine but in the beginning where would 
you put the first 3000 km of canals?
I would link the poles, the highest point on the equator (farside) for a key launching place,
 (a surface skimming orbit will not impact anywhere else) the hi-Titanium mare on Nearside
 and high Aluminum terrain in the highlands, as well as the richest Thorium and Potassium
deposits on nearside. Basically for any mineral to link at least the richest sites
so you can mine with the minumum efforts
High volatile sites would of course be a key target such to supply gasses and compounds.  .
Sulfur is also available in some minerals. I would link the sub Earth point for a comm antenna,
the anti-Earth point for a radio telescope– you can see the attraction of the idea.

Readers are welcome to list places on the Lunar surface you think should be linked with
 lunar riverboats.

When will the next great era of canal building begin?

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