When do we start colonizing?
I say right away; in the sense that we should start working on it right now, although it’ll be a while before a human actually sets foot on New Earth. How long? Dr. Travis Taylor in Alien Invasion (page 14) suggests that we humans will achieve velocities of .1 light years/year within the next few decades, on the outside. At that speed, we could reach New Earth in 5000 years, the duration being about the same as all written human history. Such a journey brings new perspective to the concept of “epic adventure,” and it is clear that space exploration beyond our own solar system will require a grand scheme.
The Kepler Telescope can tell us the size of New Earth, and its distance from its sun, but unfortunately, it cannot, as of yet, give us the planet’s chemistry, a key ingredient in its ability to sustain life, i.e. us.
Maybe a few thousand years into their journey, the colonists will determine whether they can live there. They might have to turn around and come back if the news is bad.
Back to interstellar propulsion: Close to our sun the idea of solar sails, or laser sails might work, but once the ark has proceeded far beyond our solar system the ability to project energy on the sails diminishes to, my guess, nothing.
For all practical purposes, space is a vacuum, and whatever velocity the ark has when it leaves our solar system should continue for the duration of the journey. But interstellar travel is not a practice purpose, and one wonders, if the tiniest amount of space debris would provide enough friction, over a distance of 500 light-years, to bring the craft to a dead stop, and I do mean dead. And even if it didn’t stop completely, who wants to be slowed down on a 5000 year journey?
So some method for maintaining velocity might be necessary, and some way to increase velocity (apply a thrust to the ship in deep space) would be desirable. I suppose having nuclear generators that drive atomic particles out the back could be a nuclear “rocket” engine. It could be fired occasionally to rebuild diminished momentum. Would it be possible to carry enough fuel to power a 500 light year journey?
You probably need a nuclear power plant to maintain a livable environment anyway, e.g. provide warmth and light.
If we understand cryogenics by then, the need for a livability environment might be substantially reduced. The crew that left Earth, would arrive at the destination 5000 years later. But for right now, it seems that the journey will have to be a multi-generational venture.
The limited quarters, even for a huge ship, say one 2-3 kilometers in length, would require a common ethic, culture, rule of order, or whatever you call it, no wars, no dissension, etc. Dissension is a major plot point in the second Battlestar Galactica, one of my favorite scifi series.
Social chaos in a tiny self-sustaining biosphere would be a recipe for disaster. In fact, even in the larger scope of our home planet, one wonders if the same principle applies. But how do you maintain creativity and freedom of thought while having zero tolerance for social chaos?
Possibly the best solution would be to have robots, such as the seraphim in my novels, run the ark while the humans are occasionally awakened from hibernation to breed. Their offspring would be socialized by the robots then put into hibernation until the next round of breeding was required.
Let’s say we start to build this ark somewhere near the asteroid belt, using local resources. Assuming construction will take several decades, maybe even centuries, we modularize everything so that the most recent technologies can be incorporated into the 3 kilometer long projectile (I’m assuming that indeed, aerodynamics come into play in a 500 light year journey through a not quite 100% vacuum). Our propulsion lasers have been set up around the solar system to impart the maximum feasible velocity, now .2 ly/yr, before our vessel sails beyond the range of their “laser” wind.
The date is 2150. The ark’s crew, mostly top scientists and engineers, is being recruited. The enticement: the complete encyclopedia of human knowledge is in the ark’s data banks, the best computers, laboratory and manufacturing equipment are all on board, several asteroids have been selected, or created, to provide metals, water, and other materials, and will be dragged along and processed as needed during the flight.
On Earth, the politics are stifling. Many of the best scientists are eager to become ark crewmen, although the best estimate is that the ark has a 40% chance of disaster before reaching New Earth. Most figure that will be their progeny’s problem. Oh yeah, and now we know that the chemistry of New Earth will sustain life.
Off they go.
One hundred years later, in 2250, Ark II, with speeds double Ark I, is ready to launch. Without explanation, fifty years ago, Ark I shut off the flow of data back to Earth.
Ark II has a double mission: Learn what happened to Ark I, and establish an advanced colony on New Earth before Ark I gets there.
At .4ly/yr, Ark II will reach New Earth in 1250 years. It will intercept first ark in 100 yrs, only 40ly away from Earth. But let’s say that unknown to Earth, Ark I scientists have advanced their propulsion system to achieve a velocity of .3ly/yr. They did this about the time they shut off transmission, so the intercept date becomes 250 yrs in the future.
Meanwhile, back on Earth, advances are happening faster than on either spaceship. Earth has colonized the entire solar system, therefore has lots of resources. Its population is many magnitudes larger than the spaceships’ populations, therefore it has many more geniuses to advance science. By 2300, Earth launches Ark III at .7 ly/yr speed using antimatter engines. It’s ETA at New Earth is 714.3 years. Its intercept dates for Ark II and Ark I are 67 years and 100 years respectively.
The point I’m making with this scenario is that technological advances will cause later model crafts to overtake the earlier ones long before the destination is reached. So why launch the earlier ships at all?
Because the process of building the first one develops the knowledge base that advances the second one, and maybe more importantly, the possibility of planetary disaster is ever present. There may never be a second one, or even a first one, if we don’t start soon.