Space Travel

I am one of the believers in space travel.  I have long believed that we should eventually become more than a one-planet civilization.   For most people this seems like a crazy idea but I look at it as more of an existential thing.   We know we live in this universe and occupy a minor place in it.  We know that the universe has many dangers and is incredibly large.

I also believe in humanity.  I’m a team player you could say for the human race.  In spite of our failures and clear mistakes as a species we have potential.  I would like to see us maximize that potential.   I believe that occupying more than one world and eventually making our presence felt beyond our solar system are necessary for us to achieve our full potential.

The biggest factor limiting our ability to do these things in space is the cost to lift mass out of our gravity well.    Therfore, to me and others the priority of our space program SHOULD HAVE BEEN to engineer the least cost way to get into space. Once we have accomplished that it drastically reduces the cost to do everything else making things that seem impossible today much more feasible.

For instance, it cost $200 billion to build the International Space Station.   This ridiculous waste of money was built on the flights mainly of the space shuttle which cost $2 billion / flight.   If we could have lifted mass into space at 1/10th this cost we could save maybe $100 billion or more.  Or the space station could have been 10 times bigger or some combination.   Therefore it was stupid to make a priority of building a space station when we hadn’t figured out how to make cheaper lifting mass into space.

Elon Musk has gone an incredible way in giving us a possible future here.  The development of inexpensive space travel (relatively) allows vastly more to be done with space than ever imaginable 5 or 10 years ago.    He is in the process of building the first reusable space rockets.   Such rockets cost $100 million to build with $200,000 of fuel.   Every flight we throw away the 100 million dollar space ship.   That makes space travel a lot more expensive.

Why isn’t the US governments main goal to build something like the Falcon?  Why wasn’t it it’s mission 20 years ago?  I lay the blame at government.   Driven by politics they did what was sexy in the moment and then driven by the need of jobs for the existing space program we kept doing what made no sense.   We have to make a change to a rational goal directed space program.

The first step in any space program must be the reduction in cost of delivery of mass into space

Let’s say we do that and we have a nice cheap way to go to space.   We are left with why?  Why spend the money or time?

Most people seem unmotivated about the subject.  It is not clear what the compelling motive would be besides people with an adventurous explorative and future thinking mindset.

There are 3 things I think could be compelling about going into space:

1) Financial:  There is the idea that asteroids have nearly an infinite amount of resources we could mine.  It is not clear we need all those resources if we keep the population of the earth reasonable or that they can be mined economically but we ought to find out because if there is good financial basis for going to space this would be the best reason.  Beyond this is the use of near earth space for satellites or simply transportation quickly around the earth.   Some have postulated we could get energy from the sun in solar cells and beam it back to the earth efficiently.  If any of these could be made practical they could provide financial basis for going into space and building a presence.

2) Exploration/Science:   We have a compelling need to go to space to do things to expand our knowledge of ourselves (looking back on the earth) and to do experiments for science.   We have reached to pluto and now to the very edges of the solar system.   I believe eventually we will expand this research to include other solar systems.  This will involve creation of new drive systems.

3) Colonization:    Let’s assume that for whatever reason people do decide to colonize mars or the moon for instance.    I believe by the end of the century we will have a colony on mars and that it will be thriving and large.  Possibly thousands or even millions of people.  I believe there are materials on Mars or closeby that could sustain a civilization.  I believe that our technology will be advanced enough to get around the problems of mars environment.   Eventually in hundreds of years we may terraform the planet.

Mars represents our only real second possible home other than space itself.  The other planets like Mercury and Venus seem incredibly inhospitable especially in the short term.

Development of a colony on mars or in space depends on the advancement of materials technology, robotics, health improvements, possibly genetic improvements will be utilized eventually to make us more hospitable to Mars rather than the other way around.  Certainly this makes sense from a simple economics point of view.

The cost to terraform a whole planet will be enormous and problematic.   However, modifying our genes and supplying improvements in our bodies and implants to support living in a less hospitable world seems infinitely easier and less expensive albeit with possible aesthetic concerns to most.

Some things we need to figure out / Solve before space travel beyond the moon is possible.

There are a number of things we HAVE TO figure out or any attempt to travel beyond the moon by humans is impossible.   People may not realize these things for sheer lack of interest but NASA should know and a RATIONAL space program would already have worked these things out.  They haven’t which shows our space program is being run by people who really have no interest in space but in jobs or something else.

1) We have to figure out how to simulate gravity.

Arthur Clarke in 2001: A space odyssey showed a space station that rotated.   Some may think this was just for good effect.  NO!   We have learned that humans in zero gravity for longer than 6 months even if they exercise religiously are prone to severe life threatening rehabilitation when they return to Earth.   You won’t die from zero gravity we don’t think but you may eventually be unable to return to Earth.     In any case, if space travel involves such hardship in 6 months it makes travel to Mars (9 months) and to other planets even more impractical.   We have known for a long time we can simulate gravity with rotation.   So, problem solved!   Not really.  We have never tried to live in a rotating environment.   We have no idea if the effects of doing that would be deadly.  We have no idea what size of rotation is needed or the minimal amount of gravity to sustain a viable human physique.   Is Mars 1/3 gravity sufficient to keep a human healthy and fit to return to earth?  How big a ship do we need to build to rotate that will work for humans?  We don’t know.   These are experiments we could have carried out already if we were serious about longer space travel or even if we were serious about the space station itself.   We should have built a rotating space station.   We needed lower cost to space to build that but we did it wrong.  We wasted $200 billion because the space station is not a very viable platform to build a future on.  The total space of the space station is about the size of a small mansion.   It’s large if you are a couple people but any more and it would become unlivable quickly.

Many people know we screwed up here and I won’t belabor that.   We need to have a rational program that seeks to build a rotating space station and to do experiments before that to figure out what size it needs to be, what amount of gravity we need to simulate.

venus-earth-mars-interacting-solar-wind

2) Interstellar radiation

We are protected by a magic field around the earth.   This magnetic field may be part of the reason we exist.  Planets without magnetic fields may not be able to support life.   However, when life emerged it was very resilient to radiation.  Some believe that life originated in space or on other planets (possibly even mars) and then fell on earth.   This is called panspermia and is a widely accepted way life may have started on earth.    In any case, our bodies are NOT resilient to radiation.   In order to travel outside the envelope of the Earths magnetic field which extends to about the moon we need to find a way to similarly protect ourselves.   We need spaceships that either have protective materials which can absorb the radiation or we need to have an ability to create a local “earth field” around us.   Most have focused on the protective materials approach but frequently the materials we would use to protect us are heavy which massively complicates the cost and difficulty of traveling in space.    If we have to build a spaceship that is 2 or 5 times heavier to protect us it tremendously magnifies the costs.   When we get to Mars we will have a similar problem.  The magnetic field of Mars is 10 ^ -4 (1/10,000) of the Earths magnetic field.   Thus people on Mars will experience greater radiation damage unless protected.    Recent research done in Britain and the Soviet Union show that a reasonable size electromagnet of size 1 tesla could provide protection for about 100meters.   It wouldn’t be perfect but possibly in combination with a much smaller layer of protective materials on the shell of the spacecraft could provide good protection.    We need to test this and do long term studies of animals in space using various forms of protection.

3) Robots

Because the cost of transporting humans and the danger represented by the above factors it is unworkable to have man do things that we do on earth.  We need to do as much as we can with robots.   In fact we shouldn’t even attempt to put humans on Mars or elsewhere until we have put in place all the materials in massive quantities far beyond what they would need for years of survival.   Also, we need to have robots be the main way that things get done.   This requires a lot more work in robotics, artificial intelligence and materials to enable us to have robots do lots of work in space or on Mars.

4) We need a new space station

We need to use these robots to build the spacecraft we use for interplanetary travel because these craft have to built in space.  They cannot be lifted from the earth in one piece.   So, we need to assemble them means we need a workable space station that can actually do construction.

The space station needs to be long term capable which means rotating.   We could do this in earth orbit but a more viable place to build a more permanent bigger space station is at what are called the Lagrange points.  These are 5 points that are stable gravitationally from the earth.   Space stations in these locations would be fixed in space relative to the Earth.  They are 23,000 miles away from the earth so we need an intermediate point in orbit to transit to the Lagrange points but the Lagrange points have a number of very desirable characteristics for long term occupation, construction and experimentation.

4) Mining and Materials processing

Whether we go to Mars and establish a colony, do so in open space or on the moon we need to be able to process the materials we encounter in these environments into the materials we need to survive and grow food and supply ourselves with energy.    This will take a lot of work.  We know largely in concept what materials are available on Mars and in some asteroids, the moon.   We need a lot more of this information to construct machines that can extract essential materials from the raw materials we have.    We need extremely detailed information that we don;t have.   We also need to then translate that into creative solutions for how we get all the materials we need from the raw materials and we need to figure out how to do this all robotically.

Speedier Space Travel

We have long theorized about other ways than the current combustion rockets we use today to get around in space.   Since our main problem has been getting out of the gravity well of earth the only techniques available had to have very high specific thrusts capable of overcoming the force of gravity on earth.   When you get to space numerous other space technologies become much better.   Most of these technologies use much lower specific thrust (acceleration) but last much longer enabling achievement of much higher velocities with far less mass consumption.

Ion solar powered propulsion:   The basic idea is to leverage the suns energy to accelerate particles backward from the spacecraft at incredibly high velocity.  In spite of the very low mass of the particles emitted their high velocity means that they impart a steady increase in velocity that could mean months instead of minutes of continuous acceleration.   What starts off small eventually becomes huge.   This type of propulsion is limited to very light spacecraft.

Air Force production large scale Ion Propulsion Engine X37B 

Nuclear propulsion:   A similar concept is powered instead by a nuclear source.   The nuclear source could produce many more particles at high speed much faster.   It is possible to build space ships of significant mass that use this method that can make the trip to Mars in one or two months rather than 9 or 10.

Both of these methods have already been tested and are quite practical and likely to emerge rapidly once we are simply traveling around in space from a space station.

Bussard Ramjet:   If you can put out a sail you can ride the waves of the sun.   The sun emits radiation and particles.  It is an outward wind.  Many have thought you could like a sailboat sail in space by leveraging the solar wind.  It would require a sail of incredible thinness and lightness as well as many miles in radius.  Like a sail on the ocean you would have to be able to move it to take advantage of the wind.   In some variations you use the sail to collect particles emitted by the sun, hydrogen particles in particular and then use them to create a propulsive force.  A simple Jet-like constriction, acceleration and combustion of the hydrogen would produce the thrust.  Sometimes the sail is simply left out to collect particles that are later ejected like the ion engine above to create acceleration.  The advantage of a Bussard Ramjet is that it is self-refueling.  Like the sail on the ocean this spacecraft would never be “stranded” as it could always leverage the wind in space to get around.   The continuous acceleration provided by the infinite fuel capacity means that theoretically the speed of a Bussard Ramjet is close to the speed of light eventually.    This could enable much faster space travel but it would still be years to even the closest solar system and the slow acceleration means it would still take a long time to get around our solar system.

EM-Drive

Another contender has become possible based on some NASA experiments.  A kind of “science-fiction” drive seems like it just might be possible.  The EM-drive depends on an interesting potential use of something like a swing effect.   If you take a mass M it will vary in its mass over time by some small amount due to electrical forces up and down.  I didn’t know this but it is well established.  If you apply a force to the mass when it is massive in one direction and a force in the other direction when it is less massive the object will oscillate but the net effect will be a net positive acceleration towards the direction of the force you are applying when the mass is smaller.  This would seem to violate laws of conservation of momentum but experimental evidence has verified that a theoretical possibility that one term in the momentum calculation goes to zero that results in a net positive thrust.

If you look at the link above you can see that there have been more than a dozen or so tests of this theory and several peer reviewed papers discussing it not at all proving it wrong.  Experiments now seem to conclusively show the force can be generated not only in real experiments in the atmosphere but in a vaccuum chamber at supercooled temperatures so that no thermal effects could muddy the results.

If this does turn out to be true then a drive using no ejecting mass could be generated with a simple chamber and some electrical energy source.  The force could be significant enough to lift hundreds of pounds or more into the air and forward with no reactive material being ejected.

Obviously if this is really true then it represents potentially another source of propulsion that has a number of significant benefits.  Like the Bussard Ramjet if the device can be powered from a nuclear or other significant source it could produce acceleration for decades or deceleration in free space without even collecting hydrogen atoms or sailing on the solar wind.  It could attain very high velocities not only for interstellar travel but could reduce times to Mars or other planets to days or a few weeks almost anywhere in the solar system.

This technology does not get around time dilation problems and space travel outside the solar system would be prohibitive in most cases for humans.  However, there are other versions of this technology that theoretically may provide other ways of traveling even faster.   I hesitate to mention them because I think they are extremely speculative but who knows.  If you read my blog on Physics you will see there is still a lot that is to be discovered in Physics and so nothing can truly be ruled out completely.

Travel outside the solar system

Space travel outside the solar system is fiction or fantasy at this point except in the most rudimentary way.    We could send spaceships to other solar systems but it would be something different than has ever been represented in science fiction movies.   It would be extremely dangerous, costly and time consuming.   We have voyager breaking through the barrier at the edge of our solar system now, 40 years after launch.

We could shorten dramatically the time to get to the nearest solar system.   Numerous technologies are practical to tremendously cut down the space travel time but new knowledge about the nature of the universe may unlock the way we eventually solve this problem.   I don’t think anyone can rule out discoveries that may make what we think of today as impenetrable barriers suddenly available.  I do think the nature of our universe is far different than the 4 dimensional Minkowski space our senses perceive.

Indirect Space Travel

The rate of progress in physics is impressive.  It is possible that in 20-40 years we uncover some remarkable tricks to circumvent limitations in travel.

One possibility I have never seen written about is the idea that if eventually our consciousness could be encoded into a stream of some sort of information then with an appropriate transducer at the other end we could send ourselves at the speed of light to the destination.    Such travel would have the advantage that for us traveling at the speed of light time would stop moving so that when we arrived it would seem like an instant later.  Although many tens or hundreds or thousands of years may have passed here it would allow a commuting of the species.

Predictions:

10 years:  We will be building a bigger much better space station based on reusable low cost transportation system to space.  It will be a rotating space station similar conceptually to the one in 2000: A space odyssey (25 years late),   It may or may not be located at a Lagrange point.  We will have a new space telescope capable of seeing vastly deeper and better at planets with potential life on them (The James Webb).   We will have advanced in materials and robotics to do more of the construction in space.   We will have the knowledge of materials on the asteroids and planets to make machines to utilize them.

20 years:  We will have landed and built a permanent base on Mars or the Earth albeit with very few people and possibly not occupied continuously.   We will have explored numerous asteroids and tried to mine or deliver some material from one to earth.   We will have a construction site in space at a Lagrange point or two where we have a larger facility.

30 years:  We will have a real permanent colony on mars and in orbit in space.  We will be mining some asteroids for some rare minerals.  Almost all work in space or mars will be robotic.   We will have discovered evidence of primitive life on mars.  We will be building a space telescope 10 times bigger than the James Webb telescope able to see planets around other solar systems close-by.   We will be going to another solar system with robots to explore.   We will have ion and nuclear rocket engines to make space travel 10 times faster than today allowing us to get to Mars in a month or to other solar systems in a decade.   We will have the technology to mine materials from asteroids robotically or Mars that we need on Earth and in our colonies for survival.

50 years:  We will have built our first Bussard ramjet type spacecraft for interstellar travel allowing us to send some spacecraft on journeys that are tens of light years distant.   We will have colonies on mars and the moon and space itself.   These colonies will be using resources mainly from asteroids and mars itself.    I believe we will have possibly civilizations with 100,000 people in them by the end of the 21st century on mars or in space.

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