What About the Moon?

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A Lunar Space Elevator?

Perhaps the biggest hurdle to humankind’s expansion throughout the solar system is the prohibitive cost of escaping Earth’s gravitational pull. The problem is that rocket engines work by jettisoning mass in one direction to generate thrust for a spacecraft in the other. And that requires huge volumes of propellant, which is ultimately discarded but also has to be accelerated along with the spacecraft.

The result is that placing a single kilogram into orbit costs in the region of tens of thousands of dollars. Getting to the moon and beyond is even more expensive. So there is considerable interest in finding cheaper ways into orbit.

One idea is to build a space elevator—a cable stretching from Earth to orbit that provides a way to climb into space. The big advantage is that the climbing process can be powered by solar energy and thus would require no onboard fuel.

But there is a big problem too. Such a cable would need to be incredibly strong. Carbon nanotubes are a potential material if they can ever be made long enough. But options available today are just too feeble.

A spaceline out from the Moon could be built with materials that are commercially available today.

First some background. A space elevator as conventionally conceived would consist of a cable anchored on the ground and extending beyond geosynchronous orbit, some 42,000 kilometers (26,098 miles) above Earth.

Such a cable would have considerable mass. So to stop it from falling, it would have to be balanced at the other end by a similar orbiting mass. The entire elevator would then be supported by centrifugal forces.

For many years, physicists, science fiction writers, and visionaries have excitedly calculated the size of these forces, only to be sadly disheartened by the result. No known material is strong enough to cope with these forces—not spider silk, not Kevlar, not even the strongest modern carbon fiber polymers.

Instead of anchoring the cable on Earth, what about anchoring it on the moon and dangling it toward Earth. The big difference comes from the centrifugal forces. A conventional space elevator would make a complete rotation every day, in line with Earth’s rotation. But the moon-based spaceline would orbit just once a month—a much slower rate with correspondingly lower forces.

What’s more, the forces are arranged differently. In extending from the moon to Earth, the spaceline would pass through a region of space where terrestrial and lunar gravity cancel each other out.

This region, known as a Lagrange point, becomes a central feature of a spaceline. Beneath it, closer to Earth, gravity pulls the cable toward the planet. But above it, closer to the moon, gravity pulls the cable toward the lunar surface.

Extending the cable from the moon all the way to Earth’s surface generates forces that are too great for today’s materials. But the cable need not stretch all the way to be useful.

Today’s strongest materials—carbon polymers like Zylon—could comfortably support a cable stretching from the moon to geosynchronous orbit. A proof-of-principle device made from a cable about the thickness of a pencil lead could be dangled from the moon at a cost measured in billions of dollars.

That’s clearly ambitious but by no means excessive for modern space missions. By extending a line, anchored on the moon, to deep within Earth’s gravity well, we can construct a stable, traversable cable allowing free movement from the vicinity of Earth to the Moon’s surface. The savings would be huge. It would reduce the fuel needed to reach the surface of the moon to a third of the current value.

It would open up an entirely new region of space to exploration—the Lagrange point. This is of interest because both gravity and the gravity gradient in this region is zero, making it much safer for construction projects. By contrast, the gravity gradient in low Earth orbit causes orbits to be much less stable.

If you drop a tool from the International Space Station it will seem to rapidly accelerate away from you. The Lagrange point has an almost negligible gradient in gravitational force; the dropped tool will stay close at hand for a much longer period. Neither is there any significant debris in this region. The Lagrange point has been mostly untouched by previous missions, and orbits passing through here are chaotic, greatly reducing the amount of meteoroids.

Access to the Lagrange point is a major advantage of the spaceline. The Lagrange Point base camp is most important and influential for the early use of the spaceline (and for human space exploration in general). Such a base camp would allow the construction and maintenance of a new generation of space-based experiments—one could imagine telescopes, particle accelerators, gravitational wave detectors, vivariums, power generation, and launch points for missions to the rest of the solar system.

 

Bullet Points:

** The one who starts the war is not the one who fires the first shot, but the one who causes the first shot to be fired.

** The best way to keep a prisoner from escaping is to make sure that he never knows that he’s a prisoner –  Dostoyevsky

** One more “Sanctuary State“ Governor shows himself to be a shameless hypocrite and shows the patent moral bankruptcy of “sanctuary” policies.

“After the Biden administration teased the idea of relocating New York City migrants to the Atlantic City International Airport in New Jersey, the state’s Democratic governor has come out and publicly refused to cooperate.

** Yes, of course, China claims the Moon. They claim everything. There’s a new official Chinese map claiming other nations’ lands and maritime rights. The Ten-Dash Map will undoubtedly lead to more arms purchases from the US. Thanks, Xi, you’re good for business.

The language here bears an intriguing relationship to that used by the head of the Peoples Liberation Army at this year’s Shangri La Dialogues in Singapore. Gen. Li Shangfu told the world to “mind your own business” when asked why China’s military frequently engaged in dangerous and unprofessional behavior in the East and South China Seas when other nations’ militaries were in international waters.

This latest map puts the official stamp on China’s 10-Dash Line, an upgrade from the old 9-Dash Line. Of course, the UN tribunal ruled that China’s earlier claims had no validity in international law and that China’s claims to the territories ascribed were unfounded in law or history.

I wouldn’t be surprised if they claimed Japan and the Republic of Korea with their next map.  It’s very much how they roll these days. They bought Biden cheaply.  They’re hoping that the rest of the planet will be as cheap. (it never gets old)

 

 

Identify the Aircraft

1

Do you need a hint on this one? Its impressive operational ceiling and top speed combined to make it one of the fastest Allied combat aircraft in World War I.

2

Pictured with Norwegian livery.

3

4

This one is a two-fer.

29 thoughts on “What About the Moon?

  1. Identify the Aircraft:
    1. Ansaldo SVA
    2. Sopwith Baby
    3. Vultee P-66 Vanguard
    4. Fiat G.50 Freccia

      1. 4. Didn’t notice the last photo was a two-fer. The German aircraft is the Messerschmitt Bf 110.

        1. It was optional. You’ve been awarded a bonus point.

          Save those points like Blue Chip Stamps and S&H Green Stamps and one day you’ll be able to buy a toaster with them.

  2. I’ve been reading about the space elevator in science fiction since, Oh, I don’t know the 1950s, the early 1950s.
    And how would we would require the cooperation of all the nations on Earth to establish this.
    And my first thought is always “Tower of Babel.”

    1. The US could build it unilaterally. Charge other nations to use it like a toll or like an airline landing right. Use fees.

      We print money and buy our own treasury bonds back to shore up the price. Print another trillion to cover the likely cost overruns.

  3. One note here: NJ’s blubbering aside, Atlantic City Airport is also
    part of a huge FAA and Air National Guard location. And Air Force One
    commonly uses it for practice landings and so forth.
    Nothing like having the enemy given free rein

  4. Back when I was in high school and we landed on the moon I thought that we would be well into the space elevator and lunar habitat stage by now. So much for that. Maybe in 2100?

    It seems as if China is a bully and will remain a bully. Even if the rest of the world smacks it down at one point or another it will just hunker down, wait a bit, and then try expanding again. The US and other countries have pretty much enabled Chinese expansion at the expense of other nations with agreements like the Paris Accords haven’t we?

    1. China, The Middle Kingdom, needs a Genghis Khan to come along every so often to sort things out and calm things down. Unfortunately, as with many things, the cure was worse than the disease.

    1. China needs blood to show success. They need to take the public’s mind off their malaise and misery. The problem with a blockade is that the US can respond with sanctions against China that will hurt China more. The semiconductors that Taiwan is famous for are all being made in the us now or within the next few months. US subsidies that paid for those plants to be built in the US are paying dividends.

      China is being squeezed out of Europe. Germany announced policy that felt to China like sanctions. It can get worse for China. Japan is arming for war, Australia is arming for war (subs, etc) and none of that is lost on the Middle Kingdom. A Taiwanese blockade will throw the fence sitters off the fence against China, which is viewed by a pariah state everywhere in Asia. The new ten dash map outraged Asia. It only serves to reinforce that their worst fears about China were true.

  5. “The Lagrange Point base camp”, I’m thinking the Lagrange point would be the spot for a space station. I wonder what SpaceX would charge to fly the station parts up there?
    ~~~
    “Yes, of course, China claims the Moon. They claim everything.
    There’s a new official Chinese map claiming other nations’ lands and maritime rights”… “the UN tribunal ruled that China’s earlier claims had no validity in international law and that China’s claims to the territories ascribed were unfounded in law or history.”
    The Chinese are trying to add the word “yet” to the end of that last quoted line.

    If you can get it, and keep it, it’s yours.- A natural law as old as mankind.
    ~~~
    One last thought on China claiming the moon… I read Heinlein’s book “The Moon Is A Harsh Mistress”.

  6. If babies were valuable in general, then opening an orphanage would be profitable. It’s fun watching boomer parents badger their adult married children about having grandchildren, while sporting an “I’m spending my child’s inheritance” bumper sticker on their bus-sized RV.

  7. Did a bit of decompressing today. The humidity has dropped to the point that you don’t need to worry about collisions with fish swimming through the air, so I took my bike around the mountain. Twisty road snaking down off the mountain, twisty road snaking around the mountain while going up over the mountain’s shoulder, then finishing with a twisty road going back up the mountain. Figured that if I left just after 12 noon most people would be having their Sunday dinner so traffic would be light – and it was. Still smiling 🙂

  8. Screw the Lunar cable. Go magnetic rail gun like God and Heinlein intended. Bonus is the shell can be used for other things besides carrying cargo once its in space.

    1. Sounds like a job for SpaceX since they already figured out the taking off and landing vertically just as God and Robert Heinlein intended.

      1. You could even have a compressed gasses gun firing a pusher plate or even a ‘large projectile.’ Make the gun ‘fire’ by a linear increase in pressure, kind of like the big Iraqi gun designed by Gerald Bull. Load, pooomph, load, pooomph. You’re just working to exit the Moon’s gravity, so the pooomph doesn’t have to be huge. Capture the ’round’ or cargo in orbit or even have small thrusters to push the unit into orbit, fit with another set of thrusters (or already have it equipped with them) to enter into a Hollman transfer and cargo just drifts to Earth orbit.

        None of this is hard. The hard part is getting to the Moon and setting up the equipment to make the stuff to build the stuff to make the final stuffs. All of it has been studied and written about since the 1950’s by actual material scientists and engineers and updated once we actually knew the composition of the Moon, both the surface regolith and the under stuffs.

        Seriously, there’s a thousand ways to do it. But all rely on a cheap and safe way to get equipment and personnel there.

        All eyes are on SpaceX for that.

  9. I read a sci fi books eons ago that postulated using diamond as a building material for that space elevator. The premise was the crystal structure of diamonds would resist the force of compression and torsional rotation and could be built out to just above low Earth orbit and house factories, living quarters and retail shops and sports venues.
    The diamond was mined from one of Saturn or Jupiter’s moon. For the life of me cannot remember the title or the author. There was supposedly eight of these towers in a geometric spacing and no one country could claim them as territory. I guess that would put a squash on China’s quest for for a Ten Dash+ ring…

    1. I believe 2010 a space odyssey had a ref to a diamond based space elevator.
      The diamond was thanks to a Huge chunk of diamond debris thrown off by the new star where Jupiter used to be…
      Sounds plausible, now all we need to do is figure out how to make a planet into a star and bang zoom we have our space elevator….No Problemo

      MSG Grumpy

      1. It would be nice if the national leadership could decide which bathroom to use before we move onto turning a planet into a star.

      2. Opps, the Star makin’ was in 2010, I think the space elevator was in the next book…2061??? can’t remember.

  10. And to think that up until today, all I knew about Lagrange was that there was a little shack outside of town, they got a lot of nice girls. Haw haw haw haw. Thank goodness you guys were able to refocus my mind.

  11. I’m waiting until Elon’s geniuses develop a working Bradbury transporter, the other approaches are similar to Bones interrupting Chekov’s 20th century brain surgery, “You’re going to cut into this man’s head!? How archaic, man!”, then waves a lighted piece of gear over Chekov’s head.

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