[Spaceships] getting into orbit without superscience?

[Emerikol]

I guess it all depends on how you define super science.

Since current scientific theory affirmatively declares FTL travel is not possible, anything allowing for FTL travel would be super science in my book.

But there are things that many scientists would not be surprised if they happened. So if you took a scientist 100 years into the future and we had FTL drives, that scientist would be surprised. One of the foundational theories he was taught as fact has been overturned in some way. This happens in the world of science. Newtonian mechanics were overturned by Einstein's relativistic mechanics. Scientists in Newtons day would be shocked by that. So even super science breakthroughs are not completely off the chart.

For me the next big scientific breakthrough that will change the very nature of space travel, and I expect it to happen at some point, is some sort of unified theory. Scientists are pursuing it right now. So while such an approach is "impossible" today, many think it is not forever out of reach. Unlike FTL drives. So I wouldn't call this super science. I'd call it speculative science for sure. We may never discover that theory. If we do though we can turn electrical power into gravitical thrust. We can probably bond new materials using strong and weak forces that we could never imagine creating now.

I suspect though that many would call the above super science because it is not yet possible. So your definition matters.

[Stormcrow]

Originally Posted by Emerikol

I guess it all depends on how you define super science.

GURPS clearly defines what it means by superscience, and it marks all equipment as to whether it is considered superscience or not.

"'Superscience' technologies violate physical laws... as we currently understand them" (page B513).

Superscience equipment has a "^" for its TL or, if the writer decides that it appears at a certain TL, the "^" appears after the TL number.

So the original question can be restated as: what is the most efficient way to get from the surface to orbit using only equipment that doesn't have a "^" on its TL? (And there is an implicit "also not magical" in there.)

[RogerBW]

Originally Posted by Stormcrow

So the original question can be restated as: what is the most efficient way to get from the surface to orbit using only equipment that doesn't have a "^" on its TL? (And there is an implicit "also not magical" in there.)

It's not in Spaceships; it's in Ultra-Tech, p. 224. "Space Elevator (TL9)".

Seriously – because of the problems with rockets that other people have already pointed out, any spacefaring society that can use beanstalks probably should. So spacecraft that can get to orbit may be quite specialised, not your general-purpose freight and passenger haulers.

That said, in GURPS Spaceships terms and avoiding speculation about real-world drives, assuming a vaguely earthlike planet, you want:

• TL is not ^
• number of fuel tanks needed to get to orbit is as low as possible

Spaceships 1 p. 37 says that there's no constraint on thrust if your vehicle has wings, so by a strict reading of the rules an antimatter pion drive will get the job done. But at 0.005G per drive I feel it would have some trouble overcoming air resistance (and even ignoring that, at the end of a 10,000 foot runway it's doing a mere 38 mph, not to mention the runway has been vaporised). Maybe you can loft it off a balloon or high-altitude carrier aircraft?

But let's also say we need at least 0.1G performance. TL11 high-thrust fusion pulse drive, then, with 20mps per tank of pellets. A bit marginal? External pulsed plasma will unambiguously get the job done, and you don't even need wings. Then you're down to antimatter thermal rockets, HEDM, nuclear thermal, and chemical.

[thrash]

Originally Posted by RogerBW

TL11 high-thrust fusion pulse drive, then, with 20mps per tank of pellets.

I question whether fusion pulsed drives will even function in an atmosphere, which will interfere with the "laser beams, particle beams and/or miniscule amounts of antimatter" needed for ignition and with the control of the plasma that results.

[tshiggins]

Originally Posted by RogerBW

It's not in Spaceships; it's in Ultra-Tech, p. 224. "Space Elevator (TL9)".

(SNIP)

Also, the Solar System has only one planet where humans live -- or might want to live -- in large numbers, which also has a gravity well deep enough to require exotic material for the beanstalk.

On Mars, with only 38 percent of Earth's gravity, you could probably build the elevator cable out of Kevlar or current technology carbon fiber, or something.

Every other place would only need steel cables.

[Emerikol]

Originally Posted by Stormcrow

GURPS clearly defines what it means by superscience, and it marks all equipment as to whether it is considered superscience or not.

"'Superscience' technologies violate physical laws... as we currently understand them" (page B513).

Superscience equipment has a "^" for its TL or, if the writer decides that it appears at a certain TL, the "^" appears after the TL number.

So the original question can be restated as: what is the most efficient way to get from the surface to orbit using only equipment that doesn't have a "^" on its TL? (And there is an implicit "also not magical" in there.)

I did not realize this but I did wonder about the ^ on some items.

[RyanW]

Originally Posted by Emerikol

I did not realize this but I did wonder about the ^ on some items.

It could be noted that superscience ranges from "It's magic, don't question it" to "The math works out but we don't pretend to know how it works" to "Completely realistic except for the part where it doesn't instantly melt itself at this sort of energy density."