[Spaceships] getting into orbit without superscience?
 

The options don't seem great even at higher tech levels.

Chemical rockets obviously would still work, and with higher technology would at least be more affordable due to economic growth, but they would still be inefficient at best. While reusable designs would obviously help with costs, they are not really enough to really get truly serious numbers of people to into space in an economical fashion. Would these still have any real practical use at a higher TL?

HEDM would allow getting into orbit somewhat easily with an SSTO design, but they would also have a fairly high risk of explosion given the metastable nature of the fuel in use. I'm not sure how practical it would be for military applications considering this.

Orion drives would also work, but they also involve deliberately setting off nuclear weapons within the atmosphere, which make them extremely impractical as a common launch system. NTRs have a similar radiation flaw and are also no better than metallic hydrogen in terms of delta-v with even less thrust.

Are any of the higher tech fusion or antimatter designs even capable of getting to orbit in a practical design?

Re: [Spaceships] getting into orbit without superscience?
 

NTRs need not leak radioactive materials.

As for the overall question - yes, getting off Earth (and similar planets) with realistic rockets is a pain. Non-super science fusion is a no-go. Antimatter Thermal using high-thrust and/or water versions is workable at very high TLs, but isnt really any better than HEDM chemical rockets. On top of that, unless antimatter production is extremely cheap any antimatter rocket is going to cost an enormous amount to run. On the plus-side, antimatter-catalysed hydrogen (or water) fuel doesn't count as a volatile system.

There is another option from Spaceships 7 - the laser rocket. It gives the same performance as an HEDM rocket, but is cheaper and doesn't involve volatile fuel. The catch is that it depends on powerful laser systems at the launch facility, so it's not a low-infrastructure option. Also, the propellant is really cheap.

Re: [Spaceships] getting into orbit without superscience?
 

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.

Re: [Spaceships] getting into orbit without superscience?
 

The important thing to keep in mind about NTR's is that it's the thermal bit that's crucial, it's just that said thermal energy is generated by a nuclear (fission) reactor. It should be possible to avoid making the exhaust radioactive at all, although I assume you'd lose some thrust in the mix (as you're essentially making more of the drive's mass consist of shielding). It's also possible that, even with radioactive exhaust, it's rather short-lived radiation, unlikely to cause any environmental issues. While the delta-V of NTR is decent (IIRC), I feel what makes it a real contender is the ram-rocket option, where the drive doesn't use any reaction mass so long as it's in an atmosphere above Trace. That lets you get (partially) up to speed at essentially zero cost, so you should be able to deliver a greater mass fraction into orbit. The big issue with NTR is what happens when you have a serious accident.

As I've mentioned before, you can actually help justify the expense of the launch lasers in that they can readily double as defensive systems - if it's powerful and accurate enough to launch a spaceship into orbit, it can probably take out almost any ICBM over the same hemisphere. Of course, this also means you need the permission, or be powerful enough you don't have to ask for permission, of the other polities in the same hemisphere, as you could also readily shoot down any commercial flight or similar in that area.

Re: [Spaceships] getting into orbit without superscience?
 

Space elevators are tricky to build and potentially dangerous if things go wrong, but do seem to be possible, and might end up being an efficient solution to the issue of getting into orbit, compared to rockets. There are also a few other methods of non-rocket spacelaunch that might work.

Atomic Rockets has a fairly long list of realistic Surface to Orbit concepts, both rocket (not limited to atomics) and otherwise.

Re: [Spaceships] getting into orbit without superscience?
 

Realistically, getting into space by rocket is tough and inefficient.

If you’re working out the background for a future Earth, and want to figure out how to populate the solar system, then the answer to getting into orbit is… don’t use rockets.

https://en.wikipedia.org/wiki/Non-rocket_spacelaunch is pretty thorough, and should spark your imagination.

Re: [Spaceships] getting into orbit without superscience?
 

Orion drives "should" work but there's been no serious development done on them. Everything we think we know about them depends on some back of the envelope calculations. Some of these are 1960s vintage too and might not hold up that well these days.

There's trillions of $ in engineering work before they could fly even if there are no fundamental problems.

On the other hand I've heard that Gurps' assumptions about Nuclear Thermal Rockets are overly conservative in terms of thrust-to-weight. The radioactive exhaust problem is really only about traces of the fissionable core being transferred to the exhaust. This could probably be avoided with some sort of encapsulation system.

Re: [Spaceships] getting into orbit without superscience?
 

I had always assumed the radioactive exhaust was a form of secondary radiation - bits of your fission core flaking off seems like a really bad design, so it makes more sense if you're actually looking at the exhaust being made radioactive thanks to neutron bombardment. The way to avoid that would be more shielding for the reactor.

Re: [Spaceships] getting into orbit without superscience?
 

Only the exhaust is hydrogen or maybe water. Bombarding those with neutrons causes no serious radiation problems.

If you're using hydrogen (and you want to use hydrogen for the Isp) the most you can get is tritium when one of your neutrons hits a deuteron (i in 7000 of hydrogen atoms).

Re: [Spaceships] getting into orbit without superscience?
 

If you're in atmosphere, even if you aren't using a ram-rocket design I think your exhaust would contain free neutrons, which would interact with the atmosphere to generate secondary radiation. I'd still count that as "radioactive exhaust" - although I'll admit when I'm thinking of NTR in atmosphere, I'm generally thinking of a ram-rocket (and outside of atmosphere, the radiation hazard of the exhaust probably doesn't matter - it's primarily an environmental concern, after all). Although maybe those free neutrons were what you were talking about when you said "traces of the fissionable core?"

EDIT: Of course, I could be wrong and the intent actually is that flakes of the fissionable core are somehow getting into the exhaust. That just strikes me as a monumentally poor design. Of course, looking through SS1, I see no indications that any of the drives have radioactive exhaust, so I assume that information is in a different book?

Re: [Spaceships] getting into orbit without superscience?
 

Actually, some designs would leak radiation - in the form of fuel. You see, having a barrier between the energy source (fuel) and the propellant limits how hot you can run the rocket to what that barrier can handle. So some designs relied on careful flow design to keep the fuel from (mostly) leaving. Better performance at the cost of radioactive exhaust and consuming expensive radioactives at a much higher rate.

Re: [Spaceships] getting into orbit without superscience?
 

This is why *all* reaction engine designs have trouble getting into orbit. Chemical rockets already run hot enough containing the exhaust is an issue. So there's not a lot of space for going hotter (the requirement for better fuel efficiency), which combined with the issue that heating by something other than reaction in the fuel adds weight for both the heat source and heat exchange system, means there really isn't lots of room for improvement even in theory.

The truth is that even a lot of spacecraft engines and power plants that aren't "officially" superscience really are, it's just the required superscience is the somewhat invisible "requires parts that still work at temperatures too high for chemical bonds to exist".

Re: [Spaceships] getting into orbit without superscience?
 

Well, you can use hydrogen as reaction mass instead of combustion byproducts; that allows an ISp of around 1,400 without being any hotter than current rocket. The problem is that reactors can't generally run anywhere near as hot as a current rocket engine.

Re: [Spaceships] getting into orbit without superscience?
 

Free neutrons don't constitute any sort of long-term radiation hazard. All of the major components of Earth's atmosphere are still harmless after absorbing a neutron. The neutron hitting a nucleus but not being absorbed does transfer some energy but it's pennyante stuff. You're in much more danger from the heat of the exhaust.

Re: [Spaceships] getting into orbit without superscience?
 

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.)

Re: [Spaceships] getting into orbit without superscience?
 

Mean free path of a neutron in air near is something like half a mile at 1 atmosphere, so it's a bit of a direct radiation hazard and also can activate materials on the ground.

Re: [Spaceships] getting into orbit without superscience?
 

....and dispersing these enutrons over an area of half a mile in radius doesn't reduce the concentration to negligable numbers?

Re: [Spaceships] getting into orbit without superscience?
 

A ton of heat producing equipment (i.e. reactor) will heat a lot less reaction mass to those sorts of temperatures than a ton of chemical rocket engine can burn. In other words, you can have Isp or thrust (with current or near future technology), take your pick.

Re: [Spaceships] getting into orbit without superscience?
 

That's a separate problem: closed cycle solid power plants simply can't come close to the performance of open cycle gas combustion (i.e. a rocket). This is reflected (opaquely) in spaceships

A 5 ton (SM+6) chemical rocket produces 300 tons of thrust (3 MN) with an exhaust velocity of 3 mps, for a total power output of 7 GW.

A 5 ton (SM+6) fission power plant produces 1 EP, sufficient to power a beam weapon that emits 30MJ/10s or 3MW. There's probably inefficiency there, but even if you set beam weapons to 10% the rocket is more than 200x as powerful.

You can get around that, but it generally requires open cycle. Which means you're spraying fuel out the back.

Re: [Spaceships] getting into orbit without superscience?
 

The SABRE engine is also relevant. It has two modes, acting like a ramjet at low altitudes and switching to closed cycle mode at high altitudes. Wikipedia It works really well in Kerbal Space Program. It wouldn't be suitable for a trip around the solar system though, but you could fly crew and cargo to orbit and rendezvous with a craft constructed in orbit. Another drawback is that it requires an atmosphere with oxygen (or possibly some other oxidizer?).

Re: [Spaceships] getting into orbit without superscience?
 

Places with significant atmospheres in our Solar System besides Earth comes out to Venus, Titan, Jupiter, Saturn, Uranus, Neptune and maybe Io. Of those Titan leads as a possibly desirable landing site by a wide margin.

Trying to guess about hypothetical planets/moons outside your Solar System with non-oxygen atmospheres and the biggest possiblity might be a sort of super-Mars.

So needing oxygen may not be that big a limitation

Re: [Spaceships] getting into orbit without superscience?
 

There isn't anywhere in the solar system that you're going to be taking off from (i.e. we're leaving out Venus and gas giants) with a gravity well anywhere near as significant as Earth. It takes about 8 km/s to reach Earth orbit, 3.6 km/s for Mars, 3 km/s for Mercury, and nothing else is above 2 km/s.

Re: [Spaceships] getting into orbit without superscience?
 

The ramjet mode of the SABRE engine is air breathing, burning fuel using oxygen from the surrounding air, so it is useless in an atmosphere with no oxygen.

Titan would be great for an electric propeller plane and it could work in the upper atmosphere of Venus too. XKCD Interplanetary Cessna

Re: [Spaceships] getting into orbit without superscience?
 

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.

Re: [Spaceships] getting into orbit without superscience?
 

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.

Re: [Spaceships] getting into orbit without superscience?
 

Yes, scramjets need oxygen atmospheres but our Solar System is an example of how few desirable places that rules out.

Even Titan is a sort of "There must be something worth landing there for". The upper atmosphere of Venus might be achievable but why are you going there?

Re: [Spaceships] getting into orbit without superscience?
 

Titan's atmosphere is over 5% methane, so you might be able to build a methane-breathing engine with tanks of oxygen as fuel. Or could you? (Earth's atmosphere is about 20% oxygen.

Re: [Spaceships] getting into orbit without superscience?
 

It wouldn't be terribly helpful. The big gain from atmospheric oxygen is that the oxygen is 89% of total fuel weight for hydrogen/oxygen and 75% for methane/oxygen. Using atmospheric methane with onboard hydrogen is only a 25% savings.

Re: [Spaceships] getting into orbit without superscience?
 

That presumes that larger planets have enough life for a Great Oxygenation Event. Without that, there won't be significant free oxygen: it's just too reactive.

Re: [Spaceships] getting into orbit without superscience?
 

Of course Earth-like atmospheres require life and probably photosynthesis.

The somewhat complicated thing I was tryintg to express was the concept of an exo-planet that did nto have an oxygen-bearing atmosphere yet was somehow practical and desirable for landing upon.

The universe is probably full of planets where scramjets won't work but we won't have any reason to visit them either.

Re: [Spaceships] getting into orbit without superscience?
 

On Titan you carry oxygen and use the ramjet mode to scoop in the methane atmosphere as fuel.

Re: [Spaceships] getting into orbit without superscience?
 

As noted, that doesn't help a lot. Just looking at combustion, carrying methane and using environmental oxygen gets you 55.6 MJ per kg of fuel. Carrying oxygen and using environmental methane gets you 13.9 MJ per kg of fuel, while carrying both methane and oxygen gets you 11.12 MJ per kg of fuel. By contrast, carrying hydrogen and using environmental oxygen gets you 120 MJ per kg of fuel - but carrying oxygen and using environmental hydrogen gets you only 15 MJ per kg of fuel, and carrying both is 13.33 MJ per kg of fuel. So carrying oxygen around on Titan lets you generate a little more than 10% of the energy carrying hydrogen around on Earth would, which is only a little more (less than +5%) than what using rocket fuel (LH+LOx) without an air-breathing mode would generate, and it's possible water (the only product of hydrogen combustion) is a better reaction mass than carbon dioxide (which makes up 55% of the reaction mass with methane combustion; the other 45% is water). Methane certainly isn't useless - it's cheaper and easier to store than liquid hydrogen, which is probably why SpaceX uses it - but if you're trying to get into orbit with minimal "fuel," it's probably not the way to go.

For the math on these, you need one molecule of methane for every two molecules of oxygen, and O2 has twice the molecular mass of methane. So, that's one unit mass of methane and four units mass of oxygen - carrying just methane divides methane's heat of combustion by 1, carrying just oxygen divides by 4, and carrying both divides by 5. For hydrogen, it's instead two molecules of hydrogen for every molecule of oxygen, but oxygen has 16x the molecular mass of hydrogen, for divisors of 1, 8 (only need half a mol of oxygen per mol of hydrogen), and 9, respectively.

Re: [Spaceships] getting into orbit without superscience?
 

At low velocity and altitude it can be useful to scoop atmosphere even if it doesn't provide any energy, because it acts as reaction mass, but this loses effectiveness fast and requires you to carry a lot of additional hardware. On Titan, you can get from surface to orbit with a conventional rocket and a 40% fuel fraction so I doubt anyone will bother.

Re: [Spaceships] getting into orbit without superscience?
 

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.

Re: [Spaceships] getting into orbit without superscience?
 

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

Re: [Spaceships] getting into orbit without superscience?
 

There are lots of proposals for cheap reusable ground-to-orbit systems. The catch is that virtually all of them require enormous infrastructure. Many of them could be with modern tech, they're just enormously expensive. Others are borderline superscience.

For all practical purposes, a ground-to-space flight will probably not be possible with just what a realistic ship carries. Some sort of facility on or near a planet will be necessary.

Ther's a reference here.

Re: [Spaceships] getting into orbit without superscience?
 

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."

Re: [Spaceships] getting into orbit without superscience?
 

I know I already responded, but let me put it in a different way:
Without super science or magic, getting to orbit from an Earth-sized planet is incredibly expensive and requires a truly staggering amount of infrastructure.

If you want a future society to have regular space travel, your options are

• Super-science, of some flavor and some degree of reality-bending
• A truly stunning amount of rocket launches world-wide
• Established space-plane technology and all the infrastructure to support it
• A non-rocket launch method, which requires far more upfront infrastructure and political will, but will ultimately result in a much low per-ton launch cost, which would be passed-on to the end-consumer

Each of these has follow-on implications for the setting you’re working up.

Re: [Spaceships] getting into orbit without superscience?
 

True. Let us look at those, shall we?

• Super-science, of some flavor and some degree of reality-bending

PRO: Such settings usually lend themselves well to adventuring and sensational scenarios. Including personal spaceships.
CON: Lack of reality, unforseen consequences.

• A truly stunning amount of rocket launches world-wide

PRO: Closer to realistic than most scenarios.
CON: Requires either a wealthier and more peaceful world, or a world running the razor's edge of World War Last.

• Established space-plane technology and all the infrastructure to support it

PRO: More advanced world, realistic, and has the possibility of private spacecraft.
CON: Realistic space-plane tech would be Rich Folk's Toys, which would mean the mandatory presence of wealthy PCs or powerful Patrons.

• A non-rocket launch method, which requires far more upfront infrastructure and political will, but will ultimately result in a much low per-ton launch cost, which would be passed-on to the end-consumer

PRO and CON: The sheer scale and power of most non-rocket launch facilities would require a World Government for it to exist at all. That has ramifications ranging from planetary dictatorship to a peaceful world where adventures are Simply Not Done, and anything in-between.

Re: [Spaceships] getting into orbit without superscience?
 

In a context in which metallic hydrogen is the main fuel source, might there still be applications for which chemical engines are preferred for safety reasons?

The downside to metallic hydrogen is that it is metastable, which means that while it would work in the sense of allowing for easier rocket design, it seems like it would be much higher risk in the event of damage to your craft. Mechanically it has similar dangers to antimatter, even if to a much lesser scale.

Re: [Spaceships] getting into orbit without superscience?
 

No chemical fuels are truly safe. Anything mixed with LOx is explosive. Hydrazine is deadly poisonous and fuel grade Hydrogen Peroxide is fantasticaly corossive. Then there are risks associated with cryogens you have to keep at 20 K or lower.

You probably fuel the maneuvering thrusters with some compressed gas.

Re: [Spaceships] getting into orbit without superscience?
 

While true, metallic hydrogen, being a monopropellant, would be quite capable of blowing up without any mixing (metallic hydrogen fuel is probably impossible, metallic hydrogen hasn't shown any signs of being metastable, but it's not proven impossible).

Re: [Spaceships] getting into orbit without superscience?
 

You know a story is going pretty far into rubber science when the hero's spacecraft is armoured in 'an alloy of hydrargyrum and metallic hydrogen.'

Re: [Spaceships] getting into orbit without superscience?
 

That goes so far into crazy that I have to ask where it’s from.

Re: [Spaceships] getting into orbit without superscience?
 

Not 100% certain. I think it was synthesized by my imagination mixing up other crazy things I read (I did need to go look up the old name for mercury to get the spelling right), but it might be from an old SF novel or short story I read long ago, as growing up I read a bunch that were written between 1930 and 1960 (thus, quite some time before I was born), and some that were older. I do think that I've read at least one story that used metallic hydrogen for something that it makes no sense to use metallic hydrogen for, and it may have been some sort of alloy.

Re: [Spaceships] getting into orbit without superscience?
 

I don't doubt you but I don't believe it will have been in a truly old story. I don't think it's that old a concept. Though Wikipedia does put the first prediction of its' existence in 1935.

Re: [Spaceships] getting into orbit without superscience?
 

Well, you have a lot of options for orbit without superscience... it's just that few are in Spaceships 1.

The most basic is to make a larger ship that's all fuel tanks and motors with the top third being the actual ship you want to get into space.

Then there's use of aerodynamic shapes, wings, ramjets and so on to provide the inital speed boost and then use rockets for the rest. I think stock SS has all the parts. You'll want the Ram Air Intake option for one of the more powerful drives.

Other options generally require infrastructure. For instance, you're going to want a space gun that can launch you into a suborbital trajectory where you can snag onto a skyhook to get you into space, or some other combination of those.

Re: [Spaceships] getting into orbit without superscience?
 

All of them require infrastructure. Having a booster rocket stage implies a large industrial base on the planet to make and maintain them. While flying into orbit can help, it's basically impossible with a single-stage-to-orbit model, so again you need launch ships to do the initial flying which requires ground support.

And that's the main issue with realistic spaceflight - you can't really have the tramp freighter full of PCs bouncing from backwater planet to backwater planet having fun adventures. Any planet with the industrial base to launch rockets is going to have the rocket industry dominated by large corporations.

Re: [Spaceships] getting into orbit without superscience?
 

Your best bet is probably a combination of these two things:
1. A Spaceplane, probably two stage, with Sabre engines, costs to orbit may well drop below $10 per pound.

2. Did you every read the Coyote novels? Below borrow off of them, the setting isn't Earth, at least as we know it, but rather one of several habitable moons orbiting a gas giant, this makes it possible for you to play around with things by making the planet (moon) smaller and easier to get of, it also means there's greater economic incentives for space travel (Imagine what the European powers would have done for space travel if the moon promised to be a new Africa, one without the issue of pisky natives.)

Re: [Spaceships] getting into orbit without superscience?
 

And anything which changes that (like being able to drop a "rocket seed" nanotech package which builds a booster from local materials) will probably not support tramp freighters either.

Re: [Spaceships] getting into orbit without superscience?
 

Imagine a newly colonized world. They have orbital launch capability in the form of a pair of reusable two stage sea planes, maintained in a prefabricated hanger by the shores of the settlement. In orbit sits their old colony ship (without the propulsion bus, which was sold to another colony expedition). So it's basically empty storage, some stripped down habitation and a hanger bay, but it provides the colony with a basic Class II highport, and allows them to export what ever MacGuffin led them to settling the world in the first place. Lets go with some unusually hard and beautiful timber.

Another group bought rights for a 0.4G world with a 12 hour day, so find they don't need any super materials to bring along a prefabricated space elevator. It's old and worn now, looking fuzzy with frayed wires, but while they were forced to downgrade to lighter elevator cars with less capacity for safety a few years back, it's still plenty to allow for some basic trade.

An asteroid colony is split between the old quarter and the new O'Neill cylinder that lies buried at the asteroid core, with rising tensions between those who can afford gravity and the lower classes who have to do without.

It's not particularly hard to come up with backwater worlds that have minimal infrastructure, but are capable of supporting tramp freight. And, sure, that timber colony probably has a deal with a shipping company to ship out X amount of timber per month. But so what? Even when 99% of the trade is done through long term deals with megacorporations, there's always that last 1%. Maybe the players end up loading the ship full of hand made furniture or some local plants with pharmaceutical properties, while a massive liner sweeps by to load up on all the timber.

Re: [Spaceships] getting into orbit without superscience?
 

Eh, there's multiple ways around that.

Biggest, of course, is that tramp freighters aren't about the surface-to-orbit market. So long as they can get cargoes it doesn't matter whether they're delivered by a private beanstalk, a government beanstalk, a massive disposable rocket industry, or SSTO ship's boats. A corporate dominated launch industry doesn't threaten them unless the corporate launchers refuse to provide service.

Secondly, of course, there's no reason STO has to be corporate. It probably has to be big if space trade is going to be a thing, but government-owned is certainly an option. Especially for beanstalk, launch loop, and similar systems where the fixed infrastructure is concentrated in a single collossal component.


Tangentially, you don't need superscience to be able to operate SSTOs that require little ground-side support. SS2 p19's NTR Condor Space Plane demonstrates that. It wants an airfield and a supply of hydrogen, which could be managed by a TL6 surface society! Of course it'll take a lot of flights if you're trying to ferry up a full load for an Outlander freighter (p5-6) using those.

Re: [Spaceships] getting into orbit without superscience?
 

Not this one. Space elevators mass a _lot_.

I'm kind of dubious about the seaplanes too. The first stage is not realy a problem but it's less help than soem people think too. The likely problem is that you seem to have the second stage/orbiter being a seaplane as well and I don't really think a hypersonically streamined shape is going to do well with a boat-shaped underside.

If you do look for space planes with rounded bottoms the first one you're likely to find is that one that made Col. Steve Austin into a secret government agent.

Re: [Spaceships] getting into orbit without superscience?
 

Both of these still require huge infrastructure. Which means highly populated worlds. Which tends to edge out the tramp freighter for large megahaulers, whether they're corporate owned or government run or even independently run is rather beside the point - it removes the plausibility of a small ship owned/run by PCs from being able to hop from system to system.

Beanstalks or the use of orbital transfer stations also reduces the ability of PCs to have planetside adventures, which is a primary trope of the sci-fi genre.

NTR's have their own set of problems, namely radiation - both from the reactors contaminating the atmosphere in normal use and from contamination from crashed spacecraft reactor's. Any fission reactor is also going to have limited use by non-governmental agencies, since the risks are too high of them being used as a weapon of some sort.

Re: [Spaceships] getting into orbit without superscience?
 

Why? That's not how real world tramp freight works. Tramp freight doesn't rely on liners not existing, it only relies on them not satisfying all demand.

While I don't see any actual reason that beanstalks imply megahaulers, if they did it would be to the advantage of the tramps - the bigger the haulers, the more likely that there isn't one covering the time and route that a customer needs.
Beanstalks don't reduce the ability, just the motivation. Getting a ride down the stalk shouldn't be particularly hard, but there's not a lot of reason to do so since all the business will be at the highport.
Who's going to say so? The governments on worlds that otherwise have no STO interface options?

If you think nobody will use nuclear reactors in space, yeah, that does limit a lot of things...

Re: [Spaceships] getting into orbit without superscience?
 

If the PCs are the crew of a commercial spaceship, that is. But PCs in a sci-fi game no more need to be the crew of a tramp starship than PCs in a modern game need to be commercial aircrew. I’ve been running campaigns of planetside adventures, in a setting where starships unload their passengers and cargo to orbital ports and elevator facilities, for thirty-four years with no trouble. My trick has been to specify PCs who have a job to do on planets rather than a job to do in space, and not burden them with their own spacecraft.

Besides, superscience is another a primary trope of the sci-fi adventure genre. Few of us are ever going to run a sci-fi campaign of planetary adventure without interstellar travel, and once you’ve swallowed that camel, why balk at the gnat of ground-to-orbit lighters with fusion-powered steam rockets?

Re: [Spaceships] getting into orbit without superscience?
 

The weight scales super-linearly with required length, and linearly with gravity. Length scales to the power of 1.5 with orbital period.

Space elevators on Earth might be extremely heavy, ranging from 17ktons to 1.6Mtons, depending on available tensile strength. On other worlds, they can be significantly lighter. We might be imagining very different things when we say "colony", but for me investing 10 ktons into orbital infrastructure is a sensible thing for a colony to do.

I'm not assuming a launch platform first stage, like the ones we have today. I'm talking a full blown rocketplane stage with 10 times the mass of the upper stage and 70-80% propellant. Somewhere in the 3-4km/s delta V range, off the top of my head. And that's assuming methane/lox or hydox. If metallic hydrogen is available, it can do far better. Though even with methane/lox, it would be an SSTO with 10% cargo on a Mars sized world, so it's plenty capable on its own.

The second stage doesn't really need wings, to be honest; a capsule shape with side mounted engines would do. You could even mount the engines behind protective covers if you're worried about salt water. Since it doesn't need to work in atmosphere, my preference would be to give it inflatable propellant tanks. But if your suspension of disbelief can't handle extruding pontoons through a heatshield, it probably isn't going to like inflatable tanks.

Would something like this work on Earth? Probably not. It could in theory, but not with any margin, so it's probably better to reserve this concept for worlds that take about a km/s less to orbit.

I disagree. In a multiworld setting, you don't need to build everything on world. Worlds with smaller colonies can import advanced launch structures from the bigger central worlds. If there aren't at least some highly populated worlds, where are your PCs getting a cheap secondhand ship from? Also, increased automation can make it practical for smaller colonies building bigger bits of brute infrastructure, while also making ships cheaper.

Megahaulers are only useful if they can fill their holds at their target port. So you aren't going to see them visiting ports where the beanstalk can only take 10 tons per hour, since it would take that beanstalk a decade to lift up a million tons. But the 300 ton cargo bay on a tramp is just right for a day spent transferring cargo.

Roughly half the Traveller plots I've read start with contriving some reason to separate the PCs from their ship and leave them stranded on a planet. If the campaign starting point is that ships can't land and they're always going to have to take a transfer ride to visit the surface, that's a whole lot easier to arrange.

Realistic spaceships are cramped and often don't have gravity. Most crews are going to take shore leave whenever they have the option. Especially on short sleeve worlds.

Re: [Spaceships] getting into orbit without superscience?
 

For the space elevator it was the tramp frieghter bringing one with them that I believed the weight to be too high.

If you're actually planning a giant hypersonic rocket-powered seaplane that is the point where my suspension of disbelief fails. It'd be a _lot_ easier to build one really long runway like KSC has/had for the shuttle than it would be to build a hypersonic boathulled flying machine.

Re: [Spaceships] getting into orbit without superscience?
 

OK guys, first of all it's SPACEplane, not SEAplane we're discussing at the moment, the two are very different things.

And the reason spaceplanes are attractive is that the booster stage can use jet engines, which use way less fuel.

It's a sacred cow of space gaming for some reason

Re: [Spaceships] getting into orbit without superscience?
 

If it wasn't clear, it was brought in with the colony ship, much like the high port in the first example. Just because we want things for the players to do, that doesn't mean they have to do everything in the setting.

First, it doesn't need a boathull. Very few sea planes use them. Pontoons or hydrofoils would be plenty good enough, and those can be retracted in flight. Secondly, a runway requires effort at the colony. Designing and building a space plane that can take off and land at sea requires effort at the world that sent off the colony, which likely has a lot more resources. And a standard design that works on most garden worlds can divide the design costs out among a lot of customers.

Third, we are discussing science fiction, not what we could do today. Responsive structures that can handle both hydrofoil travel and supersonic flight aren't magical impossible machines that could never exist. They'd likely be easy compared to whatever it took to get people to set up a small colony on an uninhabited world with free oxygen in the atmosphere and liquid water. Since there are no such worlds left in our solar system, we have to assume this is a civilization that has or has had access to interstellar flight, at which point they're likely able to do a few things that would be difficult for us to replicate.

But if the seaplane part is too much, feel free to reimagine the design as a VTOL instead. Same basic concept; a fully reusable two stage vehicle capable of landing on and taking off from undeveloped terrain with somewhere around 8km/s of delta V. In either case, it's designed and built by a core world, and sold to colony expeditions. For low gravity worlds, the first stage is used as an SSTO, while heavier worlds include the kick stage, which is ejected somewhere just above the planet's Karman line and lands via heatshield and parachute.

If you want a universe where tramp freighters make sense, you definitively want to have core worlds that make cutting edge high tech colony gear that needs to be transported to worlds which don't have the infrastructure to support megafreighters or regular visits by liners.

Re: [Spaceships] getting into orbit without superscience?
 

It lets PCs leave planets where they've made themselves unpopular. It lets them do smuggling, gun-running, mercenary transport and all kinds of other illegal and lucrative things. It lets the players pretend that the characters are independent of society. It also lets the GM create (or buy) scenarios that are fairly independent of the surrounding society.

Re: [Spaceships] getting into orbit without superscience?
 

Fair enough, but the same is true of superscience means of getting from ground to orbit, and FTL travel.

The OP asked about getting into orbit without superscience, and never mentioned interstellar tramp traders. Let's not force-feed them sacred beef off a different menu.

Re: [Spaceships] getting into orbit without superscience?
 

People expect a space game to have scenes in space. Certainly you can run a futuristic/SF game with more realistic space infrastructure, but it largely removes any agency on the part of the players for anything happening in actual space. All that is closely controlled by the people who own the infrastructure, who have to be good at it or it would've already collapsed, and *anywhere* well regulated by any competent authority doesn't present very many adventure opportunities. That doesn't mean you can't run a fine game where everything interesting happens on planetary surfaces, or even with no PC space travel at all, it just won't be thought of as a "space" game by most players.

Re: [Spaceships] getting into orbit without superscience?
 

If the players have no ability to travel through space on their own then there's not much use in making it a "space" game instead of a single-planet sci-fi campaign. There are some games set in such a setting that isn't Earth, but for the most part it really doesn't matter if you make the setting Earth, Alpha Centauri III, or anywhere else if it's going to be a single planet game - with the exception of a new colony/exploration setting. The larger galaxy, space travel, or any discussion of how people get to orbit or travel between stars no longer really matters when the PCs can't do it themselves.

It also just doesn't feel the same if the PCs are whisking around the galaxy on commercial transports. They might as well be hopping a plane from Paris to Shanghai for all the difference it makes. At that point you might as well just set it on Earth to make the fictional background easier to deal with.

Re: [Spaceships] getting into orbit without superscience?
 

Ah, apologies. It was not clear that the "they" who brought in the space elevator were the colonists and not the visiting PCs. It does imply a big colony ship.

For the next part I may be being technical but all "seaplanes" use boathulls. If it uses pontoons it's a "float plane". No real world aircraft use hydrofoils and all hydrofoils end up with their hulls in the water below a certain speed. It is an interesting idea for making water takeoffs and landing potentially easier and retrtactable hydrofoils would be much easier than retractible pontoons.

Still, there's that landing strip. The Shuttle made do with 15,000 feet of concrete and that's a pretty low bar for a colony to meet. That big colony ship could bring bags of concrete mix easier than it could a space elevator.

Re: [Spaceships] getting into orbit without superscience?
 

I don't know why people think tramp freight only can exist to support isolated backwater planets. Tramp freight exists today (albeit probably mostly in a very corporate sense) and had a great presence in the 20th century - not really a time when the seas were full of neglected ports.

All a tramp freighter needs is clients who need a ship available on a schedule that isn't filled by an available liner. There could be billions of tons of megahauler liners right there and still be work for a tramp freighter.

Now, one could say that developed worlds are just so big that every possible route among them would have a completely sufficient liner schedule. That might be realistic...but it's more so if the freight liners are relatively small and thus more numerous.

Re: [Spaceships] getting into orbit without superscience?
 

The Player Characters need not be ship crew to have adventures in space. They could be passengers who need to assist in thwarting would-be hijackers, try to figure out whodunnit when another passenger (or member of the crew) winds up murdered, have to keep other passengers calm and lend their own abilities to help the ship limp home (or get to an escape pod) after an accident, etc. They may well travel between exotic locales - including low-gravity asteroid colonies (like Ceres in The Expanse) - in pursuit of the plot, getting there using existing infrastructure rather than with their own spacecraft. Of course, even if they are crew, there's no reason you couldn't have them park their ship in orbit, use existing infrastructure to come down to the surface to have planetary adventures, then use that infrastructure to get back up to their ship so they can depart and have space adventures, and so forth. It might also be possible to have their "mothership" have expendable shuttles, that use soft landing systems to land on the planet, then a multistage design to get back up into orbit and rendezvous with the parked ship. A space-seaplane is probably easier to design if you just leave the pontoons behind. That can get you the ability to land on and get back off of un(der)developed planets without superscience, I feel, although you probably can't carry very many of such shuttles, so you'll have to get back to civilization once you run out (of course, you probably have to return frequently anyway, to keep topped up on your reaction mass).

Re: [Spaceships] getting into orbit without superscience?
 

Tramp freight today exists as ships owned by megacorporations who's contracts are decided by the central corporation, and who's crew have no freedom to chose clients and no personal stake in the game. It's not an exciting setting to game in.

When we talk about tramp freighters, we're talking about the Rocinante, the Serenity or the Falcon, not just about any old freighter without a fixed route.

Re: [Spaceships] getting into orbit without superscience?
 

As far as wikipedia knows, if you want to specify a plane with a boat hull that's a flying boat. If you just call it a seaplane you are either specifically indicating a floatplane (reported UK usage) or not indicating whether you mean a floatplane or a flying boat (reported US usage, and the usage I'm familiar with).

Re: [Spaceships] getting into orbit without superscience?
 

Sure, but the difference there isn't the nature of tramp freight, it's the general corporatization of the global economy.

Re: [Spaceships] getting into orbit without superscience?
 

And on any planet with an industrial base large enough to support regular rocket launches or beanstalks would you say that corporatization and/or government control of the shipping industry is likely to happen?

And on a planet that can't support regular rocket launches don't you think that the it's difficult for small ships to be able to land then take off from?

Unless, of course, you have superscience that makes taking off from those planets easier.

Re: [Spaceships] getting into orbit without superscience?
 

Adventurous tramp freight is pretty much limited to backwaters. Mostly because if it's not an isolated backwater there's going to be local people more qualified to solve whatever problem is at hand than the crew of a random spaceship.

Re: [Spaceships] getting into orbit without superscience?
 

No, I wouldn't say so.

Actually, I would say that the proposal is malformed. The space shipping industry is inherently interplanetary. It isn't controlled "on any planet"!

But that aside, you may be able to plausibly say that any large economy will be dominated by megacorporations. But frankly, you can also plausibly say that it won't. Without even needing to make an argument for it really because structure of speculative economies isn't an area with especially solid known principles. Some settings do provide reasons that vast civilization-spanning corporations might be less favored than they seem to be in current Earth history though.
As already noted, it's perfectly possible for a portable shuttle with no superscience components to do so.
If we're defining adventurous tramp freight as tramp freight where you also regularly engage in troubleshooting local problems wherever you make port, yes.

You could have adventures that are actually directly related to your business and thus either not the jurisdiction of or not something you want to present to local troubleshooters.

Re: [Spaceships] getting into orbit without superscience?
 

Perhaps. (They also expect it to have superscience.)

But similarly people expect a James Bond-inspired games of international espionage to have scenes in picturesque and glamorous locations around the world, and that does not require Bond to either own a private jet nor be flight crew on a tramp air-freighter.

Lots of times we find GMs who are designing settings ask questions in these forums about fundamentals that frame their settings but that will not be in the control of PCs. For example they ask about population densities, city sizes, and numbers and distributions of skilled-trade practitioners in low-tech settings. They ask about gravity on flat worlds. About the signs that might be left on a planet that had been terraformed millions of years ago or on which a technological civilisation had wiped itself out tens of thousands of years ago.

Just because the OP asked about ground-to-orbit capability without superscience does not mean that only tramp freighters in space are relevant.

Re: [Spaceships] getting into orbit without superscience?
 

Depends on the laws of the setting. I'm no lawyer, but I could potentially see laws structured so that a single megacorporation has a good deal of power in a colony it establishes, but antitrust regulations (from the parent polity) prevent it from establishing a full monopoly. Given the megacorporation has some control over who gets shipping contracts, it could opt to keep its large competitors (other megacorporations) at bay but encourage independently-owned vessels to handle the needed tramp freight, potentially leveraging this into positive PR (probably revolving around "helping the little guy").

Granted, I don't see tramp freighter spacecraft really being a thing in a hard science setting.

Re: [Spaceships] getting into orbit without superscience?
 

I’ve been running multiple-planet sci-fi games for over thirty years. They have been successful and well-received by scores of players. And they have never involved the PCs having private spaceships nor other means of travelling through space on their own. PCs have been Imperial law-enforcement officers, explorers working for the official Survey program, rich dilettantes travelling for recreation, intelligence officers, clandestine operators, troubleshooters for NGOs, mercenary cadre, art thieves, and undercover security & counterterrorism officials. I’ve run hundreds of adventures, the exotic geographical and social characteristics of the planets have been highly relevant, and the PCs have never had a private spaceship.

Though admittedly that setting does involve superscience for FTL travel, and limited-superscience (fusion-powered steam rockets) for ground-to-orbit services on planets with too little trade and development to afford non-rocket launch facilities.

Lots of fine adventure material involves characters such as James Bond and Indiana Jones hopping from place to place on commercial airliners. It does make a difference and is well worthwhile.

Not if dealing the the fictional background and the institutions and characters it produces is the whole damn point.

Re: [Spaceships] getting into orbit without superscience?
 

Indeed not. Limited orbital injection windows favour scheduled services.

Re: [Spaceships] getting into orbit without superscience?
 

For one example, military campaigns will be very different if one can land a recovery boat that is able to return to orbit (a la Starship Troopers), vs. having to capture the beanstalk/laser launch site/etc. or die in the attempt.

Re: [Spaceships] getting into orbit without superscience?
 

Well, current ports are huge infrastructure and the population desnities in say europe are high and yet we have a lot of tramp freighters around. Most freight by far is transported by large containerships, but yet the tramp freight exists. I do not see why this would have to be different in the given scenario.