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

[Anthony]

Originally Posted by scc

I wasn't thinking of staple crops, but rather cash ones. In particular the sorts of ones where people buy it SOLELY because it's expensive

In the end, you have the problem that you're limited to stuff that's got weight to value ratios exceeding pure gold...

[scc]

Originally Posted by Anthony

In the end, you have the problem that you're limited to stuff that's got weight to value ratios exceeding pure gold...

That will only work when there's a local supplier that can undercut the importers, if what ever it is can NOT (legally at least) be grown on the homeworld but can be on the colony things change

[Anthony]

Originally Posted by scc

That will only work when there's a local supplier that can undercut the importers, if what ever it is can NOT (legally at least) be grown on the homeworld but can be on the colony things change

That will tend to result in one of two outcomes:
1) the colony does without whatever it is.
2) whatever it is gets grown illegally.

[dcarson]

Things like the latest CPU chips might be shipped depending on the size of the colony. With each generation the cost of designing the plant get larger. So if you have a to invest 10 billion in designing and building the plant the cost per chip with a market of a few hundred million colonists is high enough that shipping just the chips (no extra parts except packaging to protect them) makes sense, they cost more then gold already if you figure just the chip weight.

You will only have a few ships however, you might get one or two ships arriving per year.

[scc]

Originally Posted by Anthony

That will tend to result in one of two outcomes:
1) the colony does without whatever it is.
2) whatever it is gets grown illegally.

You're looking at it backwards, seedcorn can not be imported FROM the colony, so anyone who wants to try the newly discovered foods must import them

[Anthony]

Originally Posted by scc

You're looking at it backwards, seedcorn can not be imported FROM the colony, so anyone who wants to try the newly discovered foods must import them

That just changes who either grows illegally or does without.

[scc]

OK, in response to some of the comments here I dropped the distance between the first two stars down to 136 AU and I'm trying to figure out what sort of travel times exist now, but I've run into something interesting.

If I set acceleration to .004G and MPS/Delta Vee to 750 (4 mag-sails or two high performance ones, the 750 is to cover both acceleration and decel) the distance traveled during boost pretty much equals the minimum separation, (122.27 AU Vs. 122.4) and takes about a year to do, but when I plug those figures into the continuous acel equation it tells me I need a DV of over a thousand and it takes 1.36 years, what gives?

[Phoenix_Dragon]

Originally Posted by scc

That will only work when there's a local supplier that can undercut the importers, if what ever it is can NOT (legally at least) be grown on the homeworld but can be on the colony things change

Remember that the fuel has to be paid for either way. If it costs $1,000+ in fuel to ship one pound of cargo to the colony, the ship needs to take in at least that much money in order to be able to operate. It might be paid for by a colonial governor instead of buyers in the colony, but they couldn't sustain that kind of purchasing for long. If this is essential foodstuffs, the colony is doomed unless there is a huge investment by the homeworld government. At such rates, it would cost upwards of half a million dollars to import enough food to feed a single person for one year.

[munin]

You can't use the max dV in the boost equation, because the ship never reaches that speed over that distance (it takes 122 au to reach 750 mps, but turn-over to decel happens at 68 au).

But I'm getting the same thing for the Continuous Acceleration equations (p. 38, sidebar). Use the equations for reactionless drives (p. 39, top-right) instead. Those give T = 12,539 hours (1.43 years) and peak velocity = 547 mps.

Once you've got the distance down to 136 au, you're not saving a whole lot of time by increasing the max dV of magsails. With 4 magsail systems maxing out at 375 mps, 136 au would take 1.56 years (178 days accel, 214 days cruise, 178 days decel), just 0.13 years more. It's not nothing, but it doesn't seem worth the change.

[scc]

Munin, the boost time equation (says) it covers both acel and decel