Space Elevators and Orbital Rings

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In the last post we brought 100 million people a day to orbit. They still need to get to the planet. At this point conventional rockets are not that terribly feasible anymore. You would be looking at space traffic that is the same as our current level of air traffic and it take a lot of energy to decelerate from orbital speeds and then also a good amount to get in and out of Earth’s gravity well. So, we need better solutions.

The Space Elevator

The space elevator has been a staple of science fiction since first popularized by Arthur C. Clarke in the novel The Fountains of Paradise. I had always thought that is were the idea came from, but it dates to 1895 when Konstantin Tsiolkovsky was inspired by the Eiffel Tower, looking at it as a building a tower to space. It was Clarke who popularized it in the novel.

The concept is that you put a space station in geosynchronous orbit, 35,786 kilomters (22,236 miles) above the equator. Any object in this orbit is moving in the same speed as the Earth’s rotation.  This means it would appear stationary in the sky. This is why for geosynchronous Direct TV satellites you point your dish toward the southern sky if you live in the northern hemisphere, northern sky in the southern hemisphere, and straight up at the equator. From the space station you drop a tether to the surface of the Earth and extend a counterweight above your station. The centrifugal force then keeps tension on the cable. You now have a cable to support an elevator to orbit.

There are two problems with this. First, we have no material strong enough for the cable to support its own weight, and second, it is a long elevator ride to orbit. Great if you are the infancy of your space infrastructure, but probably not to effective if you must move 100 million people daily.

In terms of the materials that it is being worked out. I recall a comment from Arthur C. Clarke as to when people would build a space elevator. “Fifty years after people stop laughing.” In about 2006 is about the time the concept of carbon nanotubes came out. This was considered the first material that might be strong enough for a cable. So this is about the time people stopped laughing, and there is a Japanese company planning to build one by 2050. Pretty good prediction.

Orbital Rings

An orbital ring is just as it sounds. It is a ring around the planet at a given height, typically low Earth orbit (LEO); which is 300 to 2000 km from the surface. In your orbit you are effectively falling around the Earth so at each height there needs to be a speed that keeps you falling and missing the Earth. In low Earth orbit (LEO) this is about 28,000 km/h (17,000 mph). At this speed you are orbiting the Earth every 90 minutes and there would be no way to have any tether to the surface.

The solution to this problem is to have a ring of material orbiting the Earth at orbital speeds. This can be some metal or even electrons. This is then encased in a tube. This will house the electromagnetic accelerators to keep the material up to speed and support the tube. The accelerated material provides the outward force against gravity and the tube can be stationary. You now have a structure to build space stations, hypersonic orbital maglev trains, etc. These are stationary to the planet and are not in free-fall so have almost the full gravity of Earth. Now you can drop cables to the surface that will support space elevators only 400 km in height and even trains to orbit. And we have the material science experience to make the cables today. For more details a great video to check out is Isaac Arthur’s YouTube video below.

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Wrapping Your Head Around Scale – Vacation Season

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In imagining a Kardashev II (K2) civilization, I am giving them a population of 9.5 Trillion people. When your living space is created from having a Dyson Swarm in orbit around your sun this is not a large number of people. It is in some ways a failure of the imaging to have most of your population on planets. The Star Trek universe seems expansive until you look for some population numbers. It would seem the Federation has a population of 985 billion people across 8,000 cubic light years. So, in the space of one solar system it is possible to haven 2 orders of magnitude more people. In Isaac Asimov’s Foundation series they do have a galactic empire consisting of 500 quadrillion people across 25 million planets. So that still works out to 20 billion per planet.

Any time in science fiction especially in media you see massive space infrastructure as hundreds of ships in orbit around a give area. That seems impressive given our level of technology, but where do you take that with a real K2 civilization. I am using just now and example of vacation travel. The society has moved to O’Neil Cylinders set up as their Dyson swarm. The home planet has basically been left to return to nature with now a population of 500 million to a billion people largely as caretakers. It is of course a popular vacation resort. We make the rule that you can only have one billion tourists on the planet at any given time. Using Earth as example we are going to say the average vacation is 10 days. This means Earth gets 36.5 billion tourists a year. That is 100 million per day. What does that look like in terms of orbital traffic?  We will use large shuttles of one thousand people each. That is one hundred thousand shuttles per day.  We are going to assume shuttles can be turned over in 8 hours. We are going to assume 100 orbital space ports. This means they will have to have docking for 333 ships that are changing out every 8 hours. The busiest airport in the world is Atlanta’s Hartsfield-Jackson Airport (ATL)  it has 192 gates and served about 107 million people in 2018. So effectively our space infrastructure looks more like 100 orbital spaceports double the size of the Atlanta airport.

Atlanta Hartsfield-Jackson

Hartsfield-Jackson also is big enough to have art installations along its concourses and The Plane Train, a subway to get you between terminals.  There is also the ATL SkyTrain which is the above ground mover that gets people between the concourses, the rental cars services, and the public transportation system.

Remember we have only put 100 million people a day in orbit. What is the equivalent ground transportation that gets them to the surface?  More on that in the next post.

Calculating the Kardashev Number and Just How F*ing Big a K2 Society Would Be

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Arriving at Our Kardashev Score

Previously we looked at the different Kardashev societies. The Wikipedia page gives the equation for calculating the Kardashev number. But I don’t think it is that clear, so let’s work through it. The equation is:

The Karashev equation.

K will be the Kardashev number

P is the total power output of the civilization in watts.

So where can we find some numbers. There is a World Energy Consumption Wikipedia page. You will find the data for various years given in Terawatt hours. This is for a year so you will want to break this down to the overall energy production. There are 8,760 hours in a year so by dividing by this number you now have total terawatt production. The population also adds an energy budget the Kardashev Civilization page also adds another 100 watts that each human produces. So, lets run some numbers:

Energy production 2017: 162,494 TWh

World Population 2017: 7.6 billion

So, lets run the numbers the total watts we used in 2017.

Calculation converting annual energy usage to watt hours.

Also, we need to add the population.

Calculation for how many watts to add for 7.6 billion people 100 time the population

So, the total energy is: 

Equation for total watts used by the planet 1.93095 time 10 to the 13th power of watts.

Drop this into our formula:

The Kardashev equation showing how we are a .7285 Kardashev society.

This is where we get ourselves as a Kardashev 0.72 Society.

Scaling Up for a K2 Civilization

So, let’s consider the scale of a future civilization. For purposes of a story I was going with a civilization with a population of 9.5 trillion people. I can’t think of a good way to know what the energy usage of a K2 citizen would be. We can assume they would have greater efficiency, but also more energy use. So as a starting point by dividing the 2017 energy usage by 7.6 billion people we get a per capita rate of 2,440 watts per person.

Although this is a little low since in less developed countries energy use is very low and drags down the average. Let’s scale this up to Americans who are the biggest energy users in the world. In 2008 the per capita usage in the US was 87,216 kWh. To convert this to watts we divide by 8,760 hours per year and multiply by 1,000 to get kilowatts to watts. So, the average US citizen uses 9,956 watts. Also, just to make this simply let us just round up to 10,000 watts.

Multiple that by our 9.5 trillion population energy usage is 95 quadrillion watts.

Calculation for what a population of of 9.5 trillion United States people would us 95 quadrillion watts.

This is before adding the 100 watts per person which now takes us up to 96 quadrillion watts.

Equation to a 100 watts per person for the 9.5 Trillion people.

So the new Kardashev score is:

Final Kardashev score for 9.5 Trillion people each using energy equivelent of a US citizen. Score of 1.098

So, I expanded our current population by just over 3 orders of magnitude with the energy growing linearly with that population and using more energy than the average American used in 2008 and we are only to a Kardashev 1.098 society and I am already having trouble rapping my head around the scale. Since the scale is logarithmic, just by the math you can see you are going to be using 10 to the 26th of watts of power or 100 Septillion watts if you get to a true K2 civilization. My head is beginning to hurt.

What is the Kardashev Scale

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Back in 1969 Nicoli Karadashev came up with the Kardashev scale to define the scale of future civilizations. This was based on energy use. 

Kardashev I 

A civilization that uses all of the energy that falls that is available on its planet. This is in effect all the solar energy falling on the planet for Earth approximately 1.74×1017 watts. Currently we are using about 2×1013 watts.  This makes us a Kardashev 0.7 civilization according to Carl Sagan in 1973.  

Kardashev II 

A civilization that uses all the energy of their parent star in their solar system, 4×1026 watts. This civilization has colonized their other planets. More than likely they will have a started to dismantle their planets to create space habitats. The typical view in some science fiction is building a Dyson Sphere around their sun completely to use all its energy. However even with advanced technology this seems unlikely. The only way to make it work would be to have some type of artificial gravity plating and even and this may be impossible for even hyper-advanced civilizations. 

Stephen Baxter in The Time Ships had the Morlock civilization living in a Dyson Sphere that rotated around the sun generating gravity from centrifugal force. It made for 1 g at the equator and then falling off depending on your latitude inside the sphere. 

A more realistic structure is a Dyson Swarm. In this case you build up a series of habitats around the sun infrastructure of solar panels beaming power. Various habitats maybe specialized for farming, population or industry. 

 Kardashev III 

A civilization that uses all the power of its galaxy, 4×1037 watts. This is effectively a galaxy that has been colonized with every star enclosed by a Dyson Sphere or swarm. This is truly a galactic empire. Although some functions we would have to consider here is if the speed of light is a factor. If faster than light communication or travel is possible you could have a galactic government. If it is not, then maybe just a whole cluster of K II societies with confederations of nearby stars. Eventually you will have a galaxy of many races due to divergent evolution.  

So an interesting question might be is if the speed of light is a limitation is a K III civilization even possible. 

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Utopia or Dystopia – What is the Current Trend?

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Just and interesting article from Time magazine. Even though the trend of the news media is: if it bleeds it leads. We occasionally get good news. It is worth checking out the article. Here are the biggest takeaways of what happened in the word in 2019:

  • Areas of land and water continue to get more legal protection
  • Air pollution deaths have fallen for the last 27 years
  • We are pretty close to having 90% of the world having electricity.
  • Almost at 11% of energy coming from renewables. It was about 7.5 % in 2000.
  • About 92% of the world has safe drinking water, up from about 84% in 2000.
  • The average employee make more now that any time in the last 30 years
  • Global literacy is climbing, from about 65% in 1978 to over 86%.
  • At almost 90% for children completing primary school, this is the highest in recorded history.
  • The gender gap for primary school completion rates have closed dramatically.

There is also more good news in the article. This is not to say the world is perfect, but based on trends the future still looks bright.

If you want more good news Steven Pinker’s book The Better Angels of Our Nature: Why Violence Has Declined is a very good source walking you through how prosperity has increased and violence decreased through the centuries.

Disclosure: I will use Amazon Affiliate links in where the content makes it reasonable. I will receive a commision if you click and make a purchase. However I only add links when it makes sense in the content. Content is not added just to add links.