Spaceships: How to take off?

[Anthony]

Originally Posted by Emerikol

Anyway, I know it is super science at this point in our history but solving the unified theory problem is not something completely unthinkable.

As soon as you solve that problem, one type of force can be turned into another type of force.

Understanding how something works may just cause you to realize that what you want to do is impossible.

[Ulzgoroth]

Originally Posted by Anthony

The fusion torch has a power output of bit over 2 gigawatts per ton of thrust. Even if the radiation isn't a problem, they're going blast giant craters every time they take off.

Any reason the launch from water trick used with some frequency in fiction wouldn't cover that?

[Anthony]

Originally Posted by Ulzgoroth

Any reason the launch from water trick used with some frequency in fiction wouldn't cover that?

Just produces an obnoxious safe distance. A 100 ton ship with 200 tons of thrust is producing 400 GW, which is brighter and hotter than the sun at a distance of ten kilometers (and being nearly a point source, will probably cause vision damage at hundreds to thousands).

[Fred Brackin]

Originally Posted by Ulzgoroth

Any reason the launch from water trick used with some frequency in fiction wouldn't cover that?

https://en.wikipedia.org/wiki/Sound_suppression_system

Used in more than fiction.

[Fred Brackin]

Originally Posted by Anthony

Understanding how something works may just cause you to realize that what you want to do is impossible.

Uh huh. This is the place where you discover how crappy the performance of reactionless thrusters that don't violate Conservation of Energy is.

It potentially could be better than any other hard science system but not by as much as you might hope.

[Rupert]

Originally Posted by Agemegos

The price of antimatter in Spaceships looks as though it is based on Robert L. Forward's estimate¹ of the cost of producing antimatter at TL8 combined with GURPS' posit that things' prices don't change with TL. I have tried alternatives, such as Georges Dupont-Roc's generalisation that energy technologies' real prices per joule diminish by an order of magnitude or a little bit more from their commercial introduction to their maturity. But it doesn't help very much. You need a superscience or at least limited-superscience way of making antimatter to have affordable AM-powered rocket operations.

There is a note that says:

In superscience settings where total conversion power or cosmic energy technology exists, cost of any type of antimatter reaction mass may be as little as $6,000/ton.

I've always taken that as "set the price where it works for you, but you might want to consider what that implies for your setting".

[Emerikol]

Originally Posted by Anthony

Understanding how something works may just cause you to realize that what you want to do is impossible.

That is true. We don't know what we don't know. If I could authoritatively answer on the subject then I'd know the answer and probably be rich if it works.

Still, it's not out of this world far fetched. As a basis for a science fiction campaign, I can think of other things (e.g. FTL, inertial dampers, etc..) that are far far more far fetched.

[Fred Brackin]

Originally Posted by Rupert

There is a note that says:
I've always taken that as "set the price where it works for you, but you might want to consider what that implies for your setting".

You mean things like "A metric ton of antimatter will explode for 43 gigatons."?

[Agemegos]

Originally Posted by Rupert

There is a note that says:

I've always taken that as "set the price where it works for you, but you might want to consider what that implies for your setting".

Quite.

Originally Posted by Fred Brackin

You mean things like "A metric ton of antimatter will explode for 43 gigatons."?

Yeah. According to Jon's Law any reaction drive that has enough performance to be fun is a weapon of mass destruction. But antimatter drives have it worse than any alternative. Highest possible specific impulse means highest possible exhaust velocity means highest possible power-to-thrust ratio.

[the-red-scare]

Originally Posted by Anthony

Just produces an obnoxious safe distance. A 100 ton ship with 200 tons of thrust is producing 400 GW, which is brighter and hotter than the sun at a distance of ten kilometers (and being nearly a point source, will probably cause vision damage at hundreds to thousands).

Unless I’m mistaken, the space shuttle and Saturn V were in the 40-60 GW range. Any idea where the line is between “needs a dedicated launch pad and some distance” and “slag the desert into glass?”