Realistic STL Interstellar Missions

[Anthony]

Originally Posted by Anders

You may also have people who set out because of persecution or religious or ideological zeal. They may feel there's no time to wait for better technology.

Persecuted groups don't have the resources to carry out a two hundred year project.

[Anders]

So religious or ideological zeal. Spread the faith of Zardoz throughout the Universe!

[jjordan]

Assuming you're going with sleeper or generational ships here are some adventure ideas I've had (some of which have already been mentioned):

Early in the flight:

-A cabal is seeking to take control of the ship and subvert the purpose of the colonization. Players must adapt to unexpected circumstances and improvise a resistance.

Change course to a new destination.
Take control and impose their ideology on the majority.
Kill the majority and use the resources for their own purpose.
Sabotage the mission for ideological reasons.

-"Your equipment was built by the lowest bidder." Things are failing, people are waking up. Players must assess the situation and put a solution in place.

Fix the ship?

Do they have the resources?
Do they have the expertise?
Can these be obtained?

Abandon the ship?

Just themselves?
How many people can they save?
What about those that don't want to leave?
What if you have the resources to maybe fix the ship OR abandon it, but not both?

Tough decisions have to be made.

Mid-Mission:

-Mutants. Radiation shielding has failed to do its job.

Biological terraforming tools have gotten loose and set up an ecology in the ship that is slowly destroying the ship.
Passengers have been 'corrupted' by bad drugs in the medical system and are waking up insane, blind, psychic, etc...

-Damaged systems

Lowest bidder.
Sabotage.
Unexpected space hazards.

-Oops. Technology advanced and much faster travel is now possible.

Humanity has sent a mission to re-direct the travellers to a new system, but the humans are... different. Are they telling the truth?
Space pirates found a record of the colony ship, forgotten in the strife surrounding the great technological advance, and are here to enslave everyone.
Players have been hired by a charity to uplift the members of the colony ship (upgrade their tech, teach them about galactic civilization).

-Aliens.

Investigating this strange ship.
Investigating this strange ship that has crossed the border into their empire.
Looking for clues to the origin of this invading army before they destroy the ship.
Wondering why the humans are using such a strange weapon in this latest round of the interstellar war.

-Rats in the system. The system failed to put some people to sleep and they've created their own society that's stealing supplies from the ship which is trying to hunt them down and eradicate them.

Late Mission/Arrival:

-Someone's already there.

Humans who left later.
Aliens who are native.
Aliens who colonized ahead of the humans.

-Cabal waited until the end of the mission to take over.
-Off course.

The ship won't stop.
The ship missed the star-system entirely and won't encounter another for another 300 years.
The ship is going to hit the planet it's supposed to stop at.

[AlexanderHowl]

Concerning the realism of ramscoops, it really depends on your maximum velocity. Drag increases by the square of the velocity while the energy produces increases linearly with the velocity. Using proton-proton fusion, you generate 26.73 MeV per chain (translating to 430.4 GJ/gram of hydrogen fuel). At 0.05c, each gram of hydrogen scooped effectively creates 112.5 GJ of drag, ~26.1% of the energy produced.

If we assume a 90% gathering efficiency, a 90% of the material gathered being hydrogen, and a 50% fusion efficiency, we have a total efficiency of 40.5% (174.3 GJ/gram). Since that is 55% greater than the drag, a spacecraft going 0.05c can divert some of the energy to powering the scoop, the fusion engine, and probably most of the other systems. Beyond 0.05c, the drag rapidly begins to overcome the energy production.

[David Johnston2]

Originally Posted by Anthony

Persecuted groups don't have the resources to carry out a two hundred year project.

People who want to get rid of them without bad P.R. from mass executions might. One variant on Enterprise Done Right that I considered was one in which all the colonies were established as ways of getting rid groups United Earth considered to be nuisances or who didn't like the new regime. Thus there'd be colonies founded by American militia types, Scientologists, lesbian separatists, Palestinians, organized crime groups, neo-fascists, John Norman fans...

Ehn. It was as good a basis for planets of hats as any.

[Joseph Paul]

Originally Posted by Anthony

If you pick a random 200 year period in the last 6,000 years (dawn of civilization), you win in 29 out of 30 of them.

For the OPs questions the only ones that matter are the ones in front of us so unless you foresee the creation of a .05c STL engine causing a massive slowdown in research it will be improved upon. .051, .055, .06 ... If you are an early adopter you are bound to have your tech superseded.

I chose to engineer a system wide depression and a conspiracy to hold Terra up long enough for STL ships to actually get to their worlds.

[Joseph Paul]

Originally Posted by Anthony

Persecuted groups don't have the resources to carry out a two hundred year project.

That would seem to be a bold pronouncement with out some more setting details.

[AlexanderHowl]

Originally Posted by Joseph Paul

For the OPs questions the only ones that matter are the ones in front of us so unless you foresee the creation of a .05c STL engine causing a massive slowdown in research it will be improved upon. .051, .055, .06 ... If you are an early adopter you are bound to have your tech superseded.

I chose to engineer a system wide depression and a conspiracy to hold Terra up long enough for STL ships to actually get to their worlds.

As explained above, there are quite good reasons to believe that 0.05c is the maximum feasible velocity by a ramscoop design. Anything beyond that would probably require unfeasible improvements in efficiency (or the implausible fusion up through CNO). Since 0.05c seems to be the maximum feasible velocity for a ramscoop, it seems that 0.05c would be a rather hard speed limit (baring the hideously expensive antimatter pion drive).

[ericthered]

Originally Posted by Anthony

Persecuted groups don't have the resources to carry out a two hundred year project.

The length of time a project takes isn't actually a matter of resources: its a matter of dedication. The size of the project effects this, but projects tend to scale up and down in accordance with the resources of their implementers.

The obvious comparison here is the founding of some of the original 13 colonies of the united states, and I think its a good place to make observations. Most of the groups that came were both "persecuted" but also had access to a great deal of power.

The Puritans (who settled most of new England) were a faction of protestants not favored by the current government -- at least when they founded their colony. Soon afterwards, they gained the political power to win a civil war and behead their former king. This is not a "poor" religious faction, but it was a minority faction facing persecution, despite its strength.

Compare this with the English Catholics, who settled Maryland. They were a religious faction with less power in their home country, but powerful foreign allies -- who didn't speak their language or share their culture. They were "weak" by comparison with protestant factions in england, but still had a large amount of wealth and influence.

Then you have the Quakers, who leveraged a few very rich members with fantastic connections to the king to get a colony in the new world. They are the smallest of the groups, but when you have famous members of parliament who the king owes huge debts to, that's not exactly a dearth of influence or resource.

So religious factions (or any other faction, for that matter) can scrape together the big funds needed for that sort of project, but they generally are not small things that popped up just to make a colony. They tend to be large groups that feel disenfranchised but still have a lot of wealth and influence, even if they aren't able to leverage it like they'd like. They also don't all go to the new settlement, not by far.

[(E)]

There may be opportunities to hitch a ride on a passing chunk of reaction mass.
A hypothetical chunk of ice might heading in roughly the right direction.
Other once in a thousand year occurances might be exploited as well.
A wandering planet sized object might have the resources to support a population for quite a long time.