[Space/Spaceships] Getting the velocity/Delta V I want with the tech I want

[Varyon]

Originally Posted by Belial666

1) Build ships equipped with solar sails.

2) Build space mirror(s). A big one 100 times wider than each ship's sail should do. More smaller ones might also do if you can deal with the destructive interference.

3) Aim sunlight from the mirror to the ship, propelling it with solar radiation pressure. Except you use concentrated sunlight at 10.000/1 concentration, not the pansy acceleration given by normal starlight.

I like of like this idea, although I'll note you are going to see some drop-off as you get further from your star, even if the mirrors are able to adjust and insure you're always getting all the light they reflect. You'll also end up moving the mirrors while you're at it, so they'll need some thrusters and burn delta-v to stay in their stable orbit - this works out to your vessel essentially still needing fuel, but not having to carry it itself. 0.01 gees also seems really high for light, so I suspect you'll need to make some extremely resilient solar sails (and some very good cooling systems), as otherwise you're likely to melt them.

Originally Posted by Belial666

1) Mirrors feed ship with solar power at long distances...

2) You use a tiny portion of the energy to ionize water and throw the plasma into the accelerator.

I'd imagine you'll be better off using fusion reactors - Spaceships pegs that at the same price as equivalent energy from solar panels (solar panels are half the price of a fusion reactor, but generate only half as much energy), and you also don't have the added expense of building (and maintaining, those micrometeors are going to be hell) a giant space mirror. The closest thing in Spaceships to the drive you're describing is either the ion drive (although that suggests using argon as reaction mass, implying water isn't an option) or VASIMR rocket using water as the reaction mass. In either case, you're looking at somewhere around 3 mps delta-v per tank, which isn't that great.

This may give OP an option for his drives, however - VASIMR, while TL9, is currently in development and there are already prototypes (in fact, their planning on testing one out In Spaaace in 2015, according to Wikipedia. Calling it "early TL9" may not be out of the realm of possibility. Combined with early fusion reactors (or even fission), this could allow the desired paradigm, of lower-tech, older freighters being the bulk of the business. VASIMR is in Spaceships 7 and has an impressive 10 mps delta-v, which may work rather nicely for these purposes. They also avoid the problem of magsails, which lose thrust the further they get from their star*.

*Assuming magsails simply give "free" thrust in any direction and you start at 1 AU, you're looking at an average of around 0.000024G per system for the trip - you'd need over 8 magsails to get the thrust of a single VASIMR rocket, although then you'd be able to accelerate all the way to the midpoint, then decelerate all the way to the next planet, which would shave off some time. Actually, even with the low average thrust, magsails are better than VASIMR for you - those 8 magsails would get you to your destination less than half the time of a single VASIMR rocket and 7 fuel tanks, although they'll cost a lot more (you'd have to make the round trip over a thousand times for the cost of rocket+tanks+fuel to equal the cost of those 8 magsails). The magsails are still dealing with around 6 years to go from one planet to the next, however, which may not work for you.