Humanity is standing at a fork in the road of time.  A choice that will be looked back upon for the significance of choosing rightly or will be buried under the sands of time with the rest of us.  A choice of maintaining the unnatural view that earth is the center of the universe or to accept the fact that the earth is just a little island in a great archipelago.

What other islands are there?  The moon, a three day journey hovers in the night sky with preserved footprints from a generation that dared to go.  A reminder, that great heights once scaled can become beyond reach.  Mars, a journey of some 6 months, a world with ice, an earth like day, and mineral resources to create familiar settings.  The moons of Jupiter and Saturn lay beyond.  In the spaces between, Asteroids and comets fly by like golden nuggets in the stream of the universe awaiting for the prospector’s faith to reveal their value.

We can go.  We can build ships to go to these worlds. Build structures to protect and support life.  Build systems that would allow for us to thrive there.  We could learn to make productive use of the resources of our system.  Develop the technology to live on other worlds and even between those worlds.  A huge challenge that is worthy of us to inspire and unleash our potential as only a nearly impossible challenge can.

Then once we have develop the confidence, technology, and, more importantly, the right perspective, we will be able to take that next step of sending life to another string of islands in another system.  A process that would take centuries, but once begun would lead to the populating of life throughout the universe.  And people would look back on this time with awe and disbelief that we could have done something other than accept this challenge.

On Tuesday, 9/27/2016, Elon Musk addressed an audience of about two thousand people to outline his “Mars Colonial Transportation System” which had been in the works for years.  But more importantly, he made a compelling argument about the attributes required by any system that seeks to make a radical improvement in cost of space transportation:  Full Reusability, Refilling in Orbit, Propellant Production On Mars, and Right Propellant.

Full reusablity is a must in any system that has high capital costs.  Everything from bicycles to air travel would be cost prohibitive without re-usability.  Can you imagine if every time you rode your $100 bike some place you had to build a new one?  How many bike trips could you take?  Air travel is even a better example.  When you ride a Boeing 737 some place, you are riding a $90M piece of equipment.  It holds about 180 people, which means that the cost would be $500,000 per person if it was not re-usable.  But right now you can use that plane from LA to Las Vegas for only $43 per person.  That is because the fuel only costs $10 per person.  And the plane can be use with very little maintenance on trip after trip after trip.  Full reusability is key to reducing the costs of space travel..

Refilling in orbit means that the space craft that goes to Mars can be launched with nearly empty tanks and then multiple filling trips can be made to fill the tanks.  This reduces the size of the system and allows for the materials required to go to Mars to be split across multiple launches.

Being able to produce propellant on Mars (or at other destinations) is key to reducing the cost.  It takes fuel to carry the fuel to return.  Being able to produce fuel at Mars, and use that fuel to get the space craft back to earth will be key.

In order to produce fuel on Mars, you need to make sure that you are using the right propellant.  The F9 rocket uses kerosene which is produced from oil.  And as best we know, there is no oil on Mars.  But methane is another choice.  Methane can be produced with CO2 and H2.  And since the atmosphere of Mars is 97% carbon dioxide and there is significant amounts of water ice, which can be broken into H2 and O2 using electrolysis, it would be possible to produce methane on Mars.  SpaceX has also developed and recently tested the Raptor engine which is a methane burning rocket.

With the four characteristics of Full Reusability, Refilling in Orbit, Propellant Production On Mars, and Right Propellant, it would be possible to reduce the cost of space travel to a level that would open up the solar system to more exploration and colonization.