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Is There a Starship in Your Future: Part 3 - Future Human Migration

IMG_2812 Distant Moon, 10 Light Years Away

Future Human Migration

Is There a Starship in Your future? This is my third post in this series. You will find the first two posts at dicksederquist.com

A starship traveling at 10 % of light speed would take 100 years for a 10 light year journey. Imagine a high-speed autonomous robotic vehicle visiting a star system 10 light year distant and sending back images and biological data preceding the migration of thousands of humans in self-sustaining starship world arks. Multiple generations of immigrants would live out their lives before arriving at their new home. At 2 % of light speed and a 10 light year distance, it would take 500 years to make the journey or jump between stars. Assuming another 500 years to colonize this new world and prepare for the next jump (a total of 1000 years between each jump) it would take humankind about ten million years to colonize the entire hundred thousand light year diameter Milky Way Galaxy. Ten million years is a drop in the bucket compared to the age of the Universe of fourteen billion years. That scenario would also apply to any alien civilization, who have already come and gone or will visit our solar system in the future. If they have already come and gone, they must have visited in peace and left us alone or left their mark. If you don't believe in UFOs or the new politically correct terminology, UAPs, consider that we humans could become future aliens visiting other civilizations in our galaxy. You will find a discussion on this subject in Chapter 84, Aliens and UAPs, in my fourth memoir, Taking a Walk.

I'll leave you with an image taken by an autonomous high-speed robotic vehicle of a small moon (a staging area) orbiting a viable rocky planet in a nearby star system. This probe was sent out from Earth in the year 2322, three hundred years from now. It took ten years for the electronic images and data to reach Earth. Planet Earth is in tough shape. Mars and the moons of the outer planets have been colonized. Human civilization is looking to the stars for room to grow. Will we visit them in peace?

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Is There a Starship in Your future: Ask first, Do You Live in a Gravity Well?

IMG_0184 Earth vs. Super Earth

Is There a Starship in Your future?

Before you buy a starship, you have to be able to get off the ground. Ever wonder what eventually would determine if an intelligent civilization could become a spacefaring civilization? It has to do with the size of their planet. Before becoming spacefaring, you have to be able to fly heavier than air aircraft and be able to leave the atmosphere and get into orbit around the planet, which requires rocket power. There are plenty of rocky earths out there in our galaxy in Goldilocks zones with the potential for liquid water and the creation of life. The catch is what is the diameter of that rocky planet. Take a look at the cartoon I'm holding of the Earth and a Super Earth. On the left is our Earth. I call it "Roundland" because our low gravity allows us to stand up and build tall structures; there are mountains; and the surface is obviously curved. On the right is a Super Earth which I call, "Flatland." There, high gravity keeps everything flat; even living things will be built close to the ground like my cartoon flat creature; mountains will be molehills. On a super earth about 3 times bigger in diameter than the Earth, the surface gravity would be about 3 times that on earth. That is the result of Newton's Law of Gravitation and some simple math:

F = G m1m2 / r2

Where F is the force of attraction between two bodies, G is the universal gravitational constant, m1and m2 are the respective masses of two bodies, and r is the distance between the centers of gravity of the two bodies.

The mass of a planet is roughly proportional the cube of its radius, r3. The distance from its center of gravity to the surface is its radius, r. The force of gravity is proportional to its mass, which is a function of the cube of its radius, r3, and inversely proportional the square of its radius, r2. So, the gravitational force at the surface is proportional to the radius cubed, r3, divided by the radius squared, r2, which is proportional to the radius, r. At a radius three times that of earth, your 200-pound body would weigh 600-pounds. At ten earth diameters, you would weigh a ton or 2000-pounds. Humans on Earth have evolved to stand and walk upright. We can do the high jump and pole vault. We fly airplanes and shoot rockets into space propelled by the brute force (acting over a period of a few minutes) of chemical combustion of fuels and oxidants. That rocket propulsion technology is not powerful enough to reach orbital speeds and space at much higher surface gravities than Earth. I'm logically assuming that the development of chemical propulsion rocket technology will proceed any kind of advanced (sophisticated, probably lower thrust, accelerating and braking over a period of a year) nuclear propulsion capability for interstellar space travel. The aliens living there are stuck in a gravity well, too deep to get out of. They are not going to get into space, far less, buy a starship.

Some of the biggest fish and mammals that ever lived thrive in our oceans. On a super earth, the offsetting effect of buoyancy on gravity would probably allow the evolution of life in their oceans. Whales are comfortable in the water but are unable to breath and suffocate from the effect of gravity on their organs when stranded on the beach. On land, the effect of high gravity would probably result in the evolution of flat low to the ground species like alligators that slither and drag their bellies on the ground. Even on Earth, it takes much effort for them raise themselves up and run short distances. High gravity would also create crushing atmospheric pressures and, I would guess, potentially high surface temperatures due to the higher concentration of greenhouse gases. One could imagine bacterial life existing in cooler clouds at high altitudes.

Although smaller and harder to find with present optical telescopes and techniques like gravitational wobbling and dimming of the parent star when transiting in front of the star, smaller earth size and smaller planets offer a better chance of intelligent life becoming spacefaring. There is probably a limit on the size of smaller planets in terms of ability to hold an atmosphere. We are indeed lucky here on earth, as long as we don't continue to foul our atmosphere with higher levels of greenhouse gases, carbon dioxide from burning fossil fuels and higher methane levels from leaking wells and pipelines and rotting arctic permafrost due to global warming. At least, most of the sane people have gotten the message and will do something about it. If Earth does overheat or some other space born disaster befalls our Earth or solar system, you can be happy that someone does invent a starship to escape this place.

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FUTURE STARSHIP PROPULSION

IMG_2733-1 Sketch of Future Starship

Is There a Starship in Your future?

Ever wonder what eventually would determine if an intelligent alien civilization could become a space faring civilization? It has to do with the size of their planet. Stay tuned for a future post.

Before I started writing the first nonfiction short stories and essays for my memoirs in 2002, I was always the science writer in my engineering profession, writing and co-authoring my first published paper on rocket engines in 1961 after graduating with a Bachelor of Science in Mechanical Engineering in 1959. My first job was working on storable propellant rocket engines. Storable propellant fuels and oxidizers are hypergolic, reacting, virtually exploding, on contact, no need for an ignition system. They powered the rocket engines that lowered and lifted the Apollo Lunar Lander on and off the Moon. Rockets have always been in my blood since my boyhood, good thing I never blew myself up. It's still my favorite technical subject to write about. In my third memoir, Hiking Out Again, published in 2021, there is a long chapter in my "Love of Science" section called Rocket Dreams. Here is a follow-up story that I since dreamed up for my readers. It has to do with rockets, the only way for humankind of reaching the stars. I've even included a simple picture of what that starship, and what powers it, might look like.

This essay is about the kind of things scientists and engineers have to think about when envisioning how to get there. Beyond depression, my secular prison ministry, life change strategies, and finding the humorous, and sometimes hypocritical, would you believe, things about this life, I occasionally digress and write a science story, subjects that have continued to sustain me all these years. Recently, I have been recovering from two back surgeries. I have found myself writing a lot more to sustain me during this period. Here is another story which will eventually find its way into another memoir, in the small science section, of course. It's technical, but fun to read. You will still get the hopeful message of our future travel to the stars even if you ignore the math.

This essay describes a starship utilizing CNO cycle catalyzed fusion rocket engine propulsion. CNO catalyzed fusion powers stars larger than our sun and is more efficient and energetic than the fusion process of our sun. It has often been proposed as an advanced means of propulsion for future spacecraft.

The measure of rocket engine propulsion performance is a parameter called specific impulse or I. Specific impulse (measured in seconds) is a measure of how much rocket thrust or push (e.g., pounds of force) divided by the propellant consumption rate (e.g., pounds of weight per second). The maximum velocity a vehicle can achieve when all the propellant is exhausted is Vmax if braking is not required. Vmax is the product of I times g times the natural logarithm of the quantity, 1, divided by the quantity, 1 minus f, where g is a gravitational constant (32.2 feet per second squared on Earth) and f is a fractional measure of how much of the initial fully fueled vehicle weight or mass is fuel or propellant. The term I times g or I g is the effective exit velocity of the rocket engine exhaust (units in feet per second).

Vmax = I g ln[ 1รท (1-f)]

Vmax is also approximately the sum of the allowable velocity changes a space vehicle can make over its total journey including acceleration from zero to one half Vmax, coast, and deceleration nearing its destination from one half Vmax back to zero. It turns out that there is a superior high energy nuclear fusion process which might be developed for interstellar vehicle propulsion. Energy production in our sun is predominantly created by hydrogen proton to proton (PP) fusing at high temperatures to create helium. In larger stars the fusion process operates at even higher temperatures in an efficient catalytic Carbon-Nitrogen-Oxygen cyclic process (CNO process) initiated by protons combining with carbon 12, creating unstable isotopes of nitrogen and oxygen which combine with more protons, eventually forming helium and the original carbon 12. The CNO process is more energetic and efficient than the PP fusion process and is better suited for space propulsion and achieving high specific impulses, I. Although this rocket engine propulsion technology might not be achievable in the near future, it, or a comparable technology, might be achieved in a hundred years.

Specific impulse, I, for today's chemical combustion rocket propulsion (like burning hydrogen and oxygen) is at best around 400 seconds. The specific impulse needed for interstellar travel with reasonable travel times is more like 1,000,000 seconds or 2500 times present chemical technology. This can only be achieved by matter/antimatter destruction, or more practically by a nuclear fusion process.

Nuclear fusion rockets with a specific impulse of one million or 1,000,000 seconds, or an effective exit velocity, I g, of 32,200,000 feet per second, with an initial fuel mass fraction, f, of 0.9, could achieve about 7.4 percent of the speed of light. Since braking is required when you get there, you could only achieve 3.7 percent of the speed of light (acceleration from zero to 3.7 and deceleration from 3.7 back to zero percent of the speed of light). Travel to Alpha Centauri, the nearest star system, about 4.2 light years away would take almost 120 years. That is almost five generations of travelers. Your children's, children's, children's, etc. would arrive there.

The fuel for this process is readily available. Hydrocarbons mined from distant moons within our and nearby solar systems could be used to refuel a Carbon-Nitrogen-Oxygen Cycle (CNO Cycle) catalyzed fusion rocket engine thruster. They could be used directly (a hundred percent) in a fusion rocket or provide the seed carbon (a few percent) in a CNO cycle hydrogen fusion rocket. A hydrocarbon fueled rocket engine system is described here. Hydrocarbon fuels for refueling could most likely be found in most planetary systems in our galaxy, particularly those with the colder outer planets with small icy moons. This fusion process is the characteristic energy producing process of stars larger than our sun. Sources of carbon 12 and protons (the hydrogen nucleus) initiate the CNO catalytic cycle creating helium as a final product and an incredible amount of energy. For example, methane (CH4) scooped up from one of Saturn's moon's atmospheres and fed to this fusion rocket motor could provide the carbon and hydrogen to initiate and sustain the CNO fusion cycle and reaction. The high temperature rocket exhaust contains principally hot gaseous hydrogen and carbon (methane pyrolysis products) and helium. Specific impulses, I (rocket thrust divided by propellant flow), from 1000 to 1,000,000 (units in seconds) might be achieved depending on the amount of fusion.

Specific impulses, I, of significantly greater than one million seconds (a whole new futuristic technology) are necessary to allow vehicle velocities of higher fractions of light speed and travel with reasonable travel times of 20 to 25 years to nearby stars, including acceleration, coasting, and breaking. This ship would arrive at its destination with the original astronauts and their children. This advanced propulsion technology could replace the need for building huge multi-generational self-sustaining "world arks" with thousands of inhabitants taking hundreds to thousands of years to reach their destinations depending on the rocket engine specific impulse. At an f, the fraction of vehicle mass being fuel, as high as 0.9 (big low mass envelope full of solid methane ice) and a rocket specific impulse, I, of six million seconds and an effective rocket engine exit velocity, I g, of 193,000,000 feet per second, Vmax would equal 440 million feet per second or 0.44 c, or 44% of the velocity of light, c. Since braking is required when we reach our destination, we can only attain about half that speed. That would allow travel including acceleration from zero up to 0.2 c at the beginning of the trip, coasting, and deceleration (braking) from 0.2 c at the end of the trip back to zero, with ample fuel left over, at an average velocity of almost 0.2 c, for a trip to Alpha Centauri in about 20 to 25 years. The question is how much portable infrastructure and how many astronauts, and their children, would be needed to create a self-sustaining beachhead civilization (awaiting more settlers and genetic stock) in a new star/planet system. Preceding all this would be a thorough robotic exploration of that system to see if it would support burgeoning life in a sustainable outpost.

What would this starship or interstellar vehicle look like? Any shape might be practical. In an easily pictured version, consider a cylindrical spacecraft about 50 meters in diameter and about 100 or more meters long. The temperature of interstellar space is very low. Methane fuel will be stored in the vehicle in the form of self-supporting solid methane ice. Only the lightest of shells or structures is required to contain the solid ice fuel. The mass of fuel and containment structure will be mostly fuel. The forward acceleration fuel section is at least a 67-meter-long methane ice fuel unit; the aft braking section is at least a 23-meter-long methane ice fuel unit (both enclosed in an ultralight-weight shell). They sandwich the payload, habitat, and crew section of about 10 meters between them. More methane fuel is required during acceleration because of the heavier mass of fuel at the beginning of the mission. The overall mass of the starship is initially 90% methane ice fuel. The cylinder spins slowly to create artificial gravity, the highest at the outer diameter of the cylinder and payload/crew section. The fusion rocket motor and on-board power generator is located at the end of the aft section of methane ice fuel unit. A small central access tunnel (about 4 to 6 meters in diameter, containing pipelines for carrying liquid or vaporized methane fuel to the fusion rocket motor, power cables, instrumentation, and personnel access) extends from the vehicle forward observation port, through the forward methane ice fuel unit to the payload section. A 40-meter long CNO fusion reactor rocket engine and power generator unit is housed inside the aft methane ice fuel unit. The long fusion reactor uses super magnets to accelerate the positively charged plasma of the fusion process to its exit velocity of 193,000,000 feet per second, providing the starship thrust. The positively charged ionized plasma flowing (equivalent to electric current) through the reactor generates power for the on-board power generator and super magnets.

Methane ice is used to shield the crew from lethal cosmic rays and the impact of micro dust particles and hydrogen atoms in free space impacting the spacecraft at twenty percent of light speeds. The spacecraft is turned around opposing the direction of travel during braking.

Note, that the equation for Vmax is independent of vehicle size. Without humans, and their necessary life support systems, small interstellar automated robotic vehicles could be sent out to verify the suitability of star systems for future human migration. A robotic exploration vehicle preceding one with humans would be much smaller. Without humans and their required life support system, the size of the space vehicle could be much smaller and manageable than the hypothetical one described above for a manned mission. Consider a smaller version of a manned vehicle described above, a vehicle 10-meters-long, 5 meters in diameter, a 1-meter-long instrument payload section, with a departing vehicle fuel mass fraction of 0.9. The required rocket motor size will be much smaller, and the resulting thrust will be only one-thousandths of that required for the manned mission. Flight times can be much longer, allowing a lower performance, lower specific impulse rocket engine. What an incredible achievement it would be for an autonomous, instrumented, and operational spaceship to visit another star and report back what it finds for future exploration by humans. 

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My (accidental) Breakfast with Stephen King: A True Story

Photo-on-6-21-22-at-10.42-AM-2-2 My Inspiration

I'd like to think that rubbing shoulders with a famous writer stimulated me to begin writing. Before I started memoir writing in 2002 and before the year of his publication of his nonfiction treatise "On Writing" in 2000, my wife and I found ourselves sitting next to Stephen King at a little country store and restaurant in Lovell, Maine, near Kezar Lake, where he owned a cottage. The following is an excerpt from Chapter 20, Friends Like This, from my memoir "Taking a Walk" (2022).

"When I started reading books by Stephen King, I was impressed with his characterization of children and how their bonds were built on laughter and compassion for each other. Several years ago in Maine, my wife and I, by shear chance, sat at the same lunch counter right next to the man, a short time before his terrible accident as a pedestrian on a local highway. He was having breakfast and an orange soda, voraciously reading three newspapers at his side. He says in his recent non-fiction book, "On Writing", written after his accident, that you can't write if you don't read. We were having lunch. I kept silent during the meal, but as he got up to leave, we nodded, and I told him quietly that I enjoyed his work. He graciously thanked me. The people there all knew him. He was a frequent visitor to this local restaurant and country store. It made me feel good."

As he was paying his breakfast bill, a little old lady came up to him. Paraphrasing, she said, "Mr. King, I have a story for you. It's true - - - and it's a Mystery!"

Being a local, he obviously knew her. Graciously, he replied, "Gladys (I believe that was her name), Stop by anytime. I'd love to hear it."

The photo is me in my back brace June 21, 2022, still recuperating from spinal fusion surgery in March. I'm holding my copy of "On Writing" by Stephen King.

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COLLATERAL DAMAGE

IMG_2479-1 CAGED HIKER

Collateral Damage: Consequences and Complications

In battle we have collateral damages, for example civilians killed in an air strike on military positions. From surgery, we have post-surgical consequences and complications including pain, loss of mobility, tissue swelling, potential blood clots, and with narcotic pain control, the loss of alert function and the side effect of constant constipation. You get the message, limited mobility, loss of conditioning, frustration, and worse of all for this avid but aging hiker, depression and putting hiking on hold. That's the biggest frustration of all. I haven't hiked in almost five months, trapped in a virtual cage created by surgery and the recuperation process.

The attached photo shows this frustrated hiker, trapped in a real cage, on my last hike. I guess you would call it an old cattle guard with barbed wire fencing extending to either side, allowing people (hikers) to pass through a chain link labyrinth, but too tight for cows to fit through. It's on the Metacomet Trail, south of Orchard Road, in Berlin, CT.

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