thinking about spacecraft design

[whswhs]

Originally Posted by Varyon

Depending on how high it is, there might be a sport - official or otherwise - of launching golf balls or similar with GPS dots on them into the path of the tether, then seeing how far they go after the collision - or even have targets for them to hit (the galaxy's largest golf club). But if they're only in the early days of settlement of the system as a whole, such a thing probably isn't an option, and they'll have to rely on freefall vs rocket landings. Of course, it may be more realistic for large airless worlds to be unsettled until after the good ones are fully set up and running, at which point the infrastructure to construct such a tether will already exist, you'll just need to take the finished structure into your target planet's orbit (or take the pieces and finish construction there). But if what you're shooting for is a setting where essentially everywhere inhabited is sorta The Frontier, then yeah, you'll need to have them settling the big airless worlds while they're still settling the garden worlds.

There's only one big airless world, and I'm leaning toward having its exploration deferred till later, as there are four small airless worlds that it's easy to take off from; they can land robot probes on the big one in the meantime. But I do see the small airless worlds being settled, partly by miners and partly by researchers, on account of their thermal histories (having endured their star becoming a giant and then a white dwarf).

[Anaraxes]

Originally Posted by Varyon

Depending on how high it is, there might be a sport - official or otherwise - of launching golf balls or similar with GPS dots on them into the path of the tether, then seeing how far they go after the collision - or even have targets for them to hit (the galaxy's largest golf club).

Nice. And while Bill's setting may be too early in the initial exploration phase, Flyndaran can still get some use of out the idea set a few centuries later for the interstellar cruise destinations thread.

[Donny Brook]

How about a 200+ miles long gauss catapult with rocket assistance to overcome initital inertial? Of course that won't help landing. (Or could it?)

[whswhs]

Originally Posted by Donny Brook

How about a 200+ miles long gauss catapult with rocket assistance to overcome initital inertial? Of course that won't help landing. (Or could it?)

Well, I think it would be a large project for the initial colony, and even for a settlement of ten or twenty thousand. And no, it couldn't very well help with landing; it would take insanely accurate flying to come down at its launching end and glide along its length. I think I'm going to have to go for landing craft with high acceleration and low delta-V.

[sir_pudding]

I'm curious why you rejected Advanced Fusion Pulse drives in favor of Fusion Rockets for your main interplanetary drive, the former fits your parameters as as I can tell. Expense?

[whswhs]

Originally Posted by sir_pudding

I'm curious why you rejected Advanced Fusion Pulse drives in favor of Fusion Rockets for your main interplanetary drive, the former fits your parameters as as I can tell. Expense?

Not at all. The cost is actually the same. I think I just hadn't spotted it when I was looking through the list of options.

I actually have redone my initial design using a Fusion Pulse Drive, which gives higher acceleration than either of the options you propose; using a high thrust version gives 0.1 G or just under 1 meter/second/second, enough so it actually has some maneuverability (only -1 to Handling).

I'm trying to learn how to use this system, and the process involves some thrashing around.

[sir_pudding]

The advantage of using AFP for your long-haulers is fuel efficiency.

[whswhs]

Originally Posted by sir_pudding

The advantage of using AFP for your long-haulers is fuel efficiency.

Yes. And for the larger craft that travel between the two systems I may well want that kind of design, even at the expense of reduced maneuverability. My metaphor for this campaign is "truck drivers," and it's certainly the case that big trucks can be awkward to maneuver.

[whswhs]

As of now, I've designed seven different ships with a variety of mission profiles. One of the seven, a courier, is specifically designed to travel between the two stars, carrying a shuttle onboard that can land and take off on an airless world, with two passengers. After some experimentation, I settled on an antimatter plasma rocket design with five fuel tanks.

Using some simplifying assumptions, I have it accelerating at .1G for 4.28 days, which takes its velocity to 225 miles/second; coasting for 234.68 days; and then decelerating at .1G for 4.28 days, for a total journey of 50 AU. That doesn't seem unmanageable; it's comparable to Age of Sail travel times. Of course the preferred time for missions will be closest separation of 25 AU, which will cut down travel time by nearly half.

[thrash]

Originally Posted by whswhs

As of now, I've designed seven different ships with a variety of mission profiles. One of the seven, a courier, is specifically designed to travel between the two stars, carrying a shuttle onboard that can land and take off on an airless world, with two passengers. After some experimentation, I settled on an antimatter plasma rocket design with five fuel tanks.

What logistical arrangements have you considered? Antimatter production in orbit, with hydrogen cracked from ice or hydrated minerals on the surface and shuttled up?