It's off to Zeta Zkribbler VII

[Zkribbler]

Let's say, astronomers located an Earthlike planet seven lights years away from us. And let's say, we wanted to colonize it.

What would be the best way to go about doing it? --Especially the propulsion system of the ship. (None of the SciFi fantasy stuff of hyperspace and warp drive .)

[Spiffor]

Cold fusion, obviously

[Zkribbler]

Originally posted by Spiffor
Cold fusion, obviously

Someone hand me my fish.

[Verto]

Wouldn't solar technology help out quite a bit? Obviously not to power the (entire) ship, but a lot of the subsystems? Once the ship is away from Earth, the only fuel expended should be for course corrections due to the gravity of planets and other objects along the way, but how much?

[Zkribbler]

Solar power's a possiblity.

You'd have to slingshot around the Sun to pick up momentum, because the farther away from the Sun you get, the less power you'll get from it.

If you read The Mote in God's Eye, you'll remember that the Motie ship that sailed into the human system was powered by a gigantic solar sail, albeit, it did get an initial boost from the massive firing of lasers back on Mote Prime.

Another nice thing about a solar sail is that it can also serve as a braking system.

[Kuciwalker]

Solar power doesn't work so well far from the sun...

[Verto]

Obviously, but it would last for a fair distance, wouldn't it? Provide a source of power at the beginning of the trip, and at the end.

[CrONoS]

There is no way a ship can go there... unless we find a way to transform the ego of Mobius, KrazyHorse and Asher... into a source of energy!!!!

[Kuciwalker]

Obviously, but it would last for a fair distance, wouldn't it?

Not really. The power would drop off with the square of the distance from the Sun, so it would become useless fairly quickly at the scales we're talking about.

Though you may be right that it would be a useful power source for the colonists at their destination.

[Spiffor]

Not about the propulsion system:

In any case, with current technology, the trip would last a very very long time, over several generations. Since we can't freeze people in time, the ship would need to be a functional place for people to live, and possibly to spend their entire life there. Also, since it'd be a colonization ship, it'd have to fit hundreds, if not thousands of people.

That would require a huge ship (in comparison to any other existing artificial space-object), just to make room for the people and the amenities. I can't imagine the bill to ship all the components in orbit. We'd need much better propulsion techniques than we have now for such a ship to exist outside the surface of Earth.

Also, it'd require a very complex artifical ecosystem. Currently, there are several efforts to create a simple artificial ecosystem that could feed professional astronauts during their journey on Mars. These simplistic artificial ecosystems don't work yet, but they're making slow progress.
However, the thousands of colonists won't be professional astronauts. An artificial ecosystem, to keep balance, needs to recuperate all life-supporting components that are consumed and expelled by the humans: crap, piss, sweat, CO2, corpses, what have you. A trained astronaut will probably do what it takes to store his body waste adequately. A colonist, especially a child, or a senile/crazy person, will likely not. And there will be imbalance.
In order to offset that effect, you'd need a large excess of biomass in the artifical ecosystem, which will make the ship even heavier, and even more of a pain to launch in orbit.

And don't get me started about the day-to-day life in the ship. I'm sure the politics can become quite interesting...

[Verto]

Originally posted by Kuciwalker

Obviously, but it would last for a fair distance, wouldn't it?

Not really. The power would drop off with the square of the distance from the Sun, so it would become useless fairly quickly at the scales we're talking about.

In the course of traveling seven light-years, what are the odds of coming across other 'suns'? Anyway, it would be free energy (for a little bit) that could be used both immediately, as well as stored.

[Verto]

Originally posted by Spiffor
And don't get me started about the day-to-day life in the ship. I'm sure the politics can become quite interesting...

Marijuana smoke would be spread through the ventilation system.

[Kuciwalker]

In the course of traveling seven light-years, what are the odds of coming across other 'suns'?

Fairly low, given that the closest star is 4 light years away, and charting a course to pass by a nearby star would make the overall journey take a good bit longer. At the density of stars in our region of space solar would be useless for most of the journey.

[Lancer]

Well, we can't take an A380.

[Kuciwalker]

Originally posted by Verto
Anyway, it would be free energy (for a little bit) that could be used both immediately, as well as stored.

Not free at all. The mass of the solar panels is a pretty big cost.