Thot

7 hours ago, lawrence.whitaker said:

Yet. 

After 15 billion years, I believe it is safe to say it's not going to happen. Waiting for Godot isn't even fun in theater.

2 hours ago, g33k said:

I tend to feel that we literally do not know what is possible and what is not.

Well, the last fundamental breakthrough in physics was almost a century ago. I'd love to be wrong, but it doesn't seem there are big loopholes that allow interstellar travel in this universe or any that is accessible.

If our own physics isn't indicator enough, consider this: We have not been visited.

On 10/12/2019 at 12:44 AM, seneschal said:

I'm impatient with NASA, entirely unfairly.  But we had the gear to explore the moon when I was 8 years old.  Now my grandchildren are having to wait for Mars?  We should already be colonizing the moons of Jupiter and Saturn, damn it!  Outland and 2001 A Space Odyssey should be our nightly news instead of all that other junk.  Yes, there are medical and transportation challenges still to overcome.  But it as if NASA gave up on manned space travel after the Challeger disaster.  Tragic as that was, it is a fender-bender compared to the grand struggle for mankind to spread across the world, including the New World.  Let us build our domed undersea cities Atlantis and Pacifica, then use the experiences to guide our conquest of the solar system if we can't yet reach reach the stars.  It is who we are as human beings.  Our dreams have grown too small.

And I still want my George Jetson car, dang it!

It's not just NASA. It is the universe itself.  FTL is probably impossible. Generation ships are probably impossible. Interstellar travel of all kinds probably is impossible.

We have to deal with that.

Hm, people claiming about aliens in area 51 aren't exactly reliable sources, but this sure as hell is good gaming inspiration.

FTR, NASA does not work on any actual drive. They are in way, way way too early stages for that.

On 10/2/2019 at 5:54 PM, pachristian said:

I’m fond of Traveller 2300’s stutterwarp drive. The drive propels a ship by making quantum electron jumps of a few centimeters at a time, but cycling the drive millions or billions of times a second. The drive has a variable speed, depending on ambient gravity. Once gravity exceeds 0.1 m/sec2, the stutterwarp ceases to work. Within a star system it moves the ship at sub-light speed, and once you get a certain distance out, FTL speeds. Net effect is that you need rockets to get on and off a planet, but the stutterwarp drive for interplanetary and interstellar travel. One of the smarter things they did is have a relatively low power consumption: As the stutterwarp handwavium’s you past Einsteinian physics, the starship does not need an antimatter reactor or singularity for power. Well worth checking out for hard science fiction fans.

The problem with that is that it utterly changes space combat based on a completely arbitrarily chosen form of space magic. This again doesn't ring very futuristic to me, more like fantasy.

10 minutes ago, Joerg said:

If you can provide a medium which has a signficantly lower value for C, relativistic speeds might be achievable. Chains of Bose Einstein condensates apparently have already succeeded to slow down light by several magnitudes.

I think  the speed of light is an application of a rule , not the rule itself. In other words: Speed of light in a vacuum is the maximum speed this universe will alow, but slowing down light will not decrease the maximum speed the universe allows.

Or at least that is what special relativity assumes.

On 9/30/2019 at 2:12 PM, Joerg said:

FTL but no sky hooks?

Skyhooks fail for the same reason that other would-be solutions would: Too complicated. AND they also have this issue that they'll wreck the whole planet if something goes wrong. Which it will.

Quote

Vastly improved PV cells using the solar energy from that artificial sun are another form of unobtainium.

You can use present-day technology there.

Quote

Electricity appears to be the most versatile form of energy you might want, and unobtained-yet "high temperature" supra-conductors would limit waste heat considerably, but the internal energy source for high powered output, like weaponry, magnetic shields, or similar, requires a high throughput that fuel cells with capacitors have a hard time to satisfy for a short term, let alone sustain.

Quote

Space - yes. Matter for all the platforms you might want to build for populating the Goldilocks-zone with habitats - not really.

Quote

My own setting has a kind of polynesian colonisation of the Goldilocks Zone, with one of my unobtainiums being vacuum-inhabiting life forms. Their means of propulsion remains a design challenge, though, although I am playing with media that slow down speed of light to walking speeds, thereby making relativistic accumulation of virtual mass in ring-shaped media possible, and possibly warping space-time in a way that allows warp drives. (Not necessarily FTL.)

How about just making them live for a million and then some years, and have them just use old-fashioned "poop a little gas out of the rear" drives? They'll probably lie dormant until they reach another star drifting, but they'll arrive. IF you can reach a velocity that is needed to escape the origin solar system.

2 hours ago, NickMiddleton said:

 Unless we go to the stars."

But then, you don't really need a spaceship, what you need is a self-sufficient habitat moving away from the sun early enough... So IF fusion is possible on a human-useable scale, that is what we'll see. Otherwise, we'll use some leftover uranium and hope it lasts long enough to somehow get to some other star.

3 hours ago, g33k said:

If you accelerate your reaction mass to 0.999999c, the mass is about 1000fold greater. 

If you can accelerate something to that speed, you don't need to accelerate anything to that speed.

Oh, but there can be, just not that far out. Earth orbit, solar orbit at 1 AU, maybe more of the inner system, that offers so much space (literally) that you can spend millennia there.

1 hour ago, Lloyd Dupont said:

If space travel is such a difficult matter, why bother? even today there is hardly anyone in Antarctica, and it's much easier!

I guess, it's a "realistic option" only if it's "relatively easy" (to go there, with the setting's technology) and "somewhat attractive"..

Let's see....

- science station
- biggest gravity well in the asteroid belt (gravity might help some industrial / chemical reaction, and be welcome by "local workers")
- hideout for pirate? although might be a worst hideout that some lonesome forgotten asteroid or just plan deep space...
- trade station, halfway between inner planet and outer planet, rest stop, refuel stop, etc...

mmmm.... it's all I can think of for now....

Science station? Why bother? Send a probe and do the data anlysis from Earth?

Industrial? What would you produce out there, and for who?

Pirates? Who would they be pirating on out there?

Trade station? Who would trade what there?

4 hours ago, g33k said:

Accelerate your reaction mass to near-c velocities -- even small amounts of it -- and let God and Einstein give you more reaction-mass.

The only way to do that is to convert it into photons. Lamps aren't putting out a lot of pressure, though.

8 hours ago, Joerg said:

Sure. Once you have decided to use humans like ablative armor, there is nothing to stop you from crewing expandable missiles with them.

That was the norm throughout most of human history, especially in warfare. And see Battlestar Galactica for reasons why this might be the only option.

8 hours ago, Joerg said:

Why? A micrometeorite creates a puncture and might require you to repair a number of vital systems or shut off certain systems (and activate the redundancy plans).

You have to make a choice here: Either micrometeorites are bad, or you can easily patch  holes. Which is it?

8 hours ago, Joerg said:

So basically, you FTLed to your planetary destination and then used maneuver jets for the final docking or landing?

Chemical rockets to lift off and maneuver to a certain distance from the planetary body (100,000 km), then FTL into the orbit of another planetary body within range, then land with aerobreaking (which does make sense because it's cheap to take off again with rented rockets) or just dock with a space station at the destination..

8 hours ago, Joerg said:

If this is a genetic advantage, then you will witness the birth of a hereditary class of oligarchs.

Or just gene therapy for anyone willing to go into space.

8 hours ago, Joerg said:

Since you are declaring these characters so, what is to stop you from declaring each and any of them to be a member of one of the spacefaring castes?

Because that implies they have a lot of resources, which again changes the tone of the campaign completely.

8 hours ago, Joerg said:

"Exotic" reaction mass like metal ions evaporated from an anode, as I regularly do in my AAS lamps in the lab. I can name a couple of ion sources used in mass spectroscopy, where the ion source and subsequent accelerator is essentially an ion drive(r). The technology of the ion source is about as "complicated" as a vacuum tube TV screen.

And what is the exhaust velocity of those "ion drives"?

8 hours ago, Joerg said:

Getting every aspect of technology right is impossible.

But the fundamentals of the fundamentals, like fuel consumption, the number one limiting factor in space travel, should somewhat relate to reality in a hard SF setting.

10 hours ago, Joerg said:

Yes, but a setting like that is not anywhere close to the setting outlined by M-Space.

Yes. My misunderstanding was, apparently, to see M-Space as a generic "SF guide for Mythras" instead of a more specific "this is Mythras Star Wars".

10 hours ago, Joerg said:

Only you wouldn't want to sit inside those vessels if you can remote-control them at much higher G-forces

5 m/s² is half a G. That's not something worth thinking about. And depending on your setting, there may be reasons to use human pilots over remote controls or Ai brains.

10 hours ago, Joerg said:

 

Liquid H2? You don't want to expose that to micro-meteorites providing outlets for lateral thrust...

We are talking about spaceships with the sturdiness of an airplane at most. If a micrometeorite hits you, you're dead anyway.

10 hours ago, Joerg said:

Anyway, using your fuel for shielding means that you are left without shielding for the last leg of your journey

That would be the landing - or the "we cut our tanks dry" emergency where radiation isn't your biggest concern.

10 hours ago, Joerg said:

Chemical drives are fine if you want to have a game in Earth orbit, and/or possible Earth/Moon L4 and L5 NEO capture sites. That's not quite a space opera setting, though.

Well, for my past campaign, I had to add FTL anyway, so I just decided to set the FTL drive's capabilities in such a way that chemical rockets sufficed.

10 hours ago, Joerg said:

And you said you didn't want to limit space travel to a privileged few?

Not to a hereditary class of oligarchs. If I can simply and plausibly make any PC and important NPC in my campaign a spacefarer just by declaring them so, without any other worldly consequences like fortune or fame, that's fine by me. Besides, it doesn't seem to be such a small share of the population who can stand it.

10 hours ago, Joerg said:

Yes, no computer is ever going to need more than 640 KByte RAM.

I wasn't saying that Ion drives had more delta V than necessary, but that they don't, in practice, have more delta V than chemical rockets.

10 hours ago, Joerg said:

When it comes to pushing Near Earth Objects with usable material into convenient collection sites like Earth orbit or Earth-Moon L4 and L5 points, an ion drive making use of a fraction of the payload and solar panels is vastly more efficient than sending chemical rockets and the fuel to do the job. But that's just big money you're glossing over.

For an ion drive, you need exotic reaction mass like Xenon right now - because it is freaking complicated to use non-noble gases.  There is basically no way you can mine xenon from an asteroid.

10 hours ago, Joerg said:

This vessel is of course sitting somewhere where it doesn't have to care about escape velocity any more.

Well, in orbit (at 8 km/s, roughly).

10 hours ago, Joerg said:

A 9:1 fuel to payload ratio sounds extremely optimistic to me, anyway.

Why? Once your are in orbit (and such a behemoth would be built there already), you just slap more fuel tanks onto it until you are at 90% fuel, or even more Add another 9 million tons and you get to 20,000 m/s of delta V.

10 hours ago, Joerg said:

Rather than a battleship, let's discuss something like a small O'Neill cylinder (or just a pressurized donut that diameter) being pushed to say Ceres to establish a human colony on (or rather inside) that planetoid (probably in a sub-surface O'Neill cylinder, or attaching your travel cylinder to a pole of Ceres). You'll probably want to send two such vessels at the same time.

Why would anyone want to build a colony on Ceres? There is nothing there that you cannot find elsewhere closer to the sun.

10 hours ago, Joerg said:

With a target like that, you need to provide enough fuel to brake at the target, then stabilize your rendezvous orbit for years. You don't even have to carry the fuel for the return trip - such reaction mass would be harvested from Ceres.

Assuming similar mass and getting the initial acceleration from Earth completely by booster modules (some of which you might harvest a few years after your arrival for return missions to Earth), you can slow down from 10km/s. The shortest possible distance between Earth and Ceres is 250 million kilometers, resulting in a journey of a bit less than 3000 days or a little under 8 years. In practical reality, your path would probably be at least twice as long. Still, 15 years of interplanetary journey sound remotely possible with chemical rockets

Cassini needed 7 years to get to Saturn. Kickstarted with a liftoff rocket (a Titan IV), and with 2000 m/s on-board delta V.

10 hours ago, Joerg said:

What's your hurry with acceleration and deceleration?

Ion drives and the even less powerful higher Isp drives are not noticeably accelerating, meaning there is no action going on, which is bad for tension at the game table. And they don't seem to give that impressive results in practice anyway. The space probe Dawn had only about 11,000 m/s of delta V. Compared to our Battlerocket Solaria, I can only say: Why bother with the ion thruster, plus the power source, plus the waste heat, plus the extremely rare reaction mass in the form of Xenon?

 

2 hours ago, Joerg said:

While there is no hard physical barrier preventing technology that produces magnetic shields able to ward off cosmic radiation, there is a problem with the energy consumption for such a device.

I can imagine some workaround by incredibly sophisticated magnetic field shapes. But there simply is no option whatsoever to get rid of the limitations of reaction mass.

Quote

 

No argument here. So why your fascination with chemical rockets? 😋

Because they are real. We could build such ships right now. Elon Musk's SpaceX is beginning to. They do seem to be as close to the real thing as we'll ever be.

Quote

If you assume an "ether" of Dark Matter pervading the galaxy,

Then of course everything is different. But it doesn't look like it.

Quote

But I agree with your disagreement on reactionless action.

Yet, conservation of momentum poses a problem with all FTL travel.

You don't need FTL in order to have a space setting.

Quote

No jet fighter dog fights this way, no.

Actually, that IS doable. With some 5000 m/s of delta v and an acceleration of 0.5g (similar to most atmospheric fighter jets today), you could do 20 minutes of constant burning. If you limit yourself to relatively low speeds, that can be enough to do traditional dogfighting. Only for half an hour or so (as you don't burn CONSTANTLY), but that's good enough for a carrier vs carrier battle.

Quote

building a carnot engine to use stored potential energy to move distributed heat to concentrated heat is easy. Getting the source of stored potential energy for that is hard.

Even in the best case that will just add to your overall waste heat.

Quote

You need supraconducting magnet coils to avoid frying yourself warding off cosmic radiation (or counteracting the Jovian asteroid belt) if you plan to survive your space trip.

No, storing enough H2 around you is actually an option. And as you need that for your rocket anyway... but sure, a magnetic field would be convenient.

Quote

You mean ballistic objects after assisted acceleration (true, using chemical rockets) with minimal thrust for course correction?

Of course. That is what real space travel is: Some chemical rockets and lots of orbit calculations.

Quote

Power generation aboard a space ship... ok, that's an issue when you are far from the Goldilocks zone. As long as you are within collector range of a primary, you can collect sun light, and by skewing your collector sail you can use that collection for a bit of additional thrust. Photovoltaic collectors will generate electric energy, most likely to be stored chemically or in sufficiently dimensioned condensators. Rotational energy in gyros would be possible, too, but a bit self-defeating when what you want to use the energy for is to accelerate or decelerate mass.

As a chemist, you will surely know how important it is to quantify such statements.

The amount of energy for a high Isp drive is... unsettling.

Quote

Really? Getting the fuel flow right is a bitch - that's why Korolev's umpteen drive moon rocket didn't take off. The few big rocket exhausts of the Saturn were anything but blue collar friendly, either.

I never claimed it wasn't hard, just that other drives are even harder.

Quote

Gigawatts in terms of chemical energy translate as megatons of fuel, so there is no way you'll be happy with your chemical thrusters, either.

The beauty of the chemical rocket is that it carries its power in its fuel, and that takes most of that out of the rear end of your spacecraft with it. Yes, you need really large amounts of fuel for high delta V, but it seems to be easier to just accept that and have a very large tank than to build overcomplicated drives that never quite achieve what you design them for.

We live under the tyranny of the rocket equation, and this is not going to change.

Quote

That kind of gravity isn't habitable - tidal nausea will incapacitate your crew, rather than prevent bone degradation and fluid build-up.

Not at all. NASA has done tests with it - some people cannot stand it, yes, but others can. For my campaign, I just assumed all relevant characters had passed that test.

Quote

What do you call "impressive" in terms of space drives? Your chemical rocket only leaves you coasting after a short boost, the ion drive doesn't offer short boosts but has a greater output during the journey.

Well, all that effort to just get some 10,000 m/s of delta V when you could as well just put more fuel on your spaceship... seems wasted.

Quote

Just out of interest, if you want a gigawatt of propulsive force generation, how many Saturn rockets do you need to lash together, and how long can they maintain this output?

You could do that computation (based on E=1/2m*v²), but by putting it in terms of energy, you are making things complicated because of the rocket equation.

Let's just imagine a rocket ship, let us call it the Battlerocket Solaria. Without fuel, it is about as massive as a Nimitz class aircraft carrier, so about 100,000 tons.We want our Battlerocket Solaria to have significant delta V, so we give it a fuel tank with 900,000 tons of fuel. Therefore, the starting mass (fully loaded) is 1,000,000 tons. With a H2/O2 rocket, that will give us:

Delta V=4462*LN(1,000,000/100,000)

which equals 10,274 m/s of total Delta V.

How big the engine is that we use this fuel with is irrelevant for that, but we'll probably equip our Battlerocket Solaria with missiles and fighters for armament, so the mothership won't need to be terribly agile. The Saturn V rocket's engine had a thrust of 33,851 kN. let us give our battlerocket three of those, so we have about 100,000 kN of hrust. When the Battlerocket Solaria is fully loaded, her engines will accellerate her at  1 m/s², which goes up to 10m/s² when the tanks are almost dry. She could do this for about 2,000 seconds non-stop - but you'd never do that, of course.

On 9/27/2019 at 12:07 AM, Joerg said:

You somehow doubted the ability of the M-Space system to cater to chemical rockets, whereas I wanted to point out that the ship design is based on the tech tree M-Space inherited from Traveller, with weird spots of softness in the SF behind it.

Well, Traveller CAN do chemical rockets and other reaction thrusters. M_space doesn't seem to have that option at all.

On 9/27/2019 at 12:07 AM, Joerg said:

 

Shielding the payload (whether the on-board AI / heuristic or organisms, or just organic or highly organized matter) from the hostile environment is quite essential. Even maintaining digital data integrity is a challenge

Sure, but there is no had physical barrier preventing tech to solve these issues. Reaction mass is different in that you cannot work around the need for it.

On 9/27/2019 at 12:07 AM, Joerg said:

So what is the hurry to change course and velocity? It is not like anybody will be surprised that the target object comes into range.

Slow motion  is boring?

On 9/27/2019 at 12:07 AM, Joerg said:

Reactionless thrusters are impossible with current ability to manipulate gravity or spacetime.

No. Reactionless thrusters as depicted in Traveller and M-Space are flat-out impossible, full stop.

The only way it IS possible is with photons as your reaction mass, and that requires amounts of energy no foreseeable spaceship will ever have accessible. Even then, thrust would be so low that they'd not be worth it, except for interstellar voyages.

On 9/27/2019 at 12:07 AM, Joerg said:

The main problem is to have an energy source that doesn't produce vast amounts of waste heat

Every joule of energy you produce eventually becomes waste heat. You can get rid of some by putting it in the reaction drive's exhaust, but that is necessarily imperfect.

On 9/27/2019 at 12:07 AM, Joerg said:

I am a chemist, and that makes me doubt chemical energy as a viable long range solution.

Worked fine for all the deep space probes any group of humans has sent out, with few exceptions.

On 9/27/2019 at 12:07 AM, Joerg said:

Not delta V, just V.

V follows from delta V. A chemical rocket can at most have an impact velocity of something like 10km/s. Bad for the house or block it hits, but rather unimpressive on the city. Not so with a fusion rocket that gives you 200.000 km/s of delta V...

On 9/27/2019 at 12:07 AM, Joerg said:

Magnetic coils and electrodes aren't exactly rocket science. Chemical rockets are... by definition.

But you forgot more than half of the drive here: The power source. The additional cooling. The reaction mass that needs to be cooled even more.

On 9/27/2019 at 12:07 AM, Joerg said:

Do you really think that uneducated blue-collar work will be able to maintain high-tech beyond their home culture? That's like putting wipers with oily rags in charge of a fusion reactor.

No, I am saying that high Isp-drives are even more complicated than chemical rockets, and we hit a limit there, too.

On 9/27/2019 at 12:07 AM, Joerg said:

Yes, that's the question. The energy source with the least waste heat would be the hydrogen oxygen fuel cell, leaving the waste product as reaction mass.

See above: It is not about the efficiency of the power source. You will always have 100% of your stored energy as waste heat EVENTUALLY, except for that which you put out of your engine.

On 9/27/2019 at 12:07 AM, Joerg said:

I still advocate external energy, photovoltaic cells, most likely focussed by a solar sail also providing thrust while braking towards the light source or accelerating away from it.

Photovoltaics is great technology, but it won't power a multi-GW-spaceship. And that's what you need for high Isp ships..

On 9/27/2019 at 12:07 AM, Joerg said:

Ship size is extremely limited if you want chemical propulsion for its sublight drive.

Only by your ability to build stable hulls that can handle the acceleration stress. The size of a single rocket engine is limited, yes, but you can just use multiple engines.

On 9/27/2019 at 12:07 AM, Joerg said:

Any rotating body is a gyro, and quite hard to convince to change direction.

That wasn't my point. If you have gyro core (or just two countering centrifugges, all you need is the ability to create rotation (like a common motor), wihtout having to spend any delta V.

On 9/27/2019 at 12:07 AM, Joerg said:

Are ion drives that complicated?

Judging by the time and effort put into their development without having anything terribly impressive to show for yet, I would say yes.

On 9/27/2019 at 12:07 AM, Joerg said:

Light sails in combination with solar powered lasers (or mirrored beams) can provide constant thrust in periods you would otherwise coast, and reduce a lot of fuel requirements.

The amount of sail surface needed for that to be noticeable on a timescale relevant for manned space flight is prohibitive.

On 9/27/2019 at 12:07 AM, Joerg said:

I can see some attraction in making the planetary young adult novels of Heinlein featuring reusable chemical rockets the background for a space game. The technology modeled in M-Space is far beyond that level, though. Yes, it is possible to design lower tech-level vessels with the M-Space rules, or to alter the technology tree, but that requires alterations to the ship design rules.

And I had hoped someone had done the groundwork already.

15 hours ago, Joerg said:

You'll end up with vastly different ship designs when you don't allow for artificial gravity.

I don't quite see why this is a reply to the sentence you quoted immediately before that?

15 hours ago, Joerg said:

Fuel is just one aspect that may get glossed over.

It's extremely fundamental, in contrast to the other things you mention, as it limits the ship's core ability (velocity change) significantly and cannot be explained away without violating major physics laws, unlike with waste heat, for instance (because at least there are radiator concepts that could theoretically work up to some point; rectionless thrusters are flat out impossible if we are not talking about lamps photon drives).

15 hours ago, Joerg said:

Like I said, hydrogen plasma exhaust gets better exhaust velocities, and exhaust velocity is where the rocket equation gets power from.

But there are issues with higher specific impulse drives that, at close distance, look quite significant, to sy the least.

1. If you do the math for the waste heat, you find that your crew is boiled, or with some  thrusters, the ship is melted, regardless of what kind of cooling system you imagine.

2. Their accellerations are so incredibly low that crews don't notice them. Which also means it takes a boring amount of time to get to any desired speed.

3. Too much delta V in the hands of basically any civilian tramp freighter captain mean every doofus owns a weapon of mass destruction.  Chemical rockets don't really pose that problem.

4. All the higher specific impulse drives are incredibly complicated, which means expensive and prone to failure. Do you really want spacecraft to be a privilege of the top 0.001% in your interstellar empire?

5. What is the power source?

15 hours ago, Joerg said:

That changes when your ammunition gets "intelligent". The difference between the long range battleship combat of WW1 and WW2 and the Falkland conflict rocket attacks.

I don't quite see how the nature of the missile changes the fact that the ships basically don't move, so there is no maneuvering, merely a quite boring ECM battle which ends the moment one side is hit.

15 hours ago, Joerg said:

The tethered countermass rotation is the only viable options for vehicles you can push to more than walking speed with chemical rockets, causing significant fuel expenditure to build up/slow down the rotation.

They are all viable, depending on the size of the ship.

You can do rotation with a gyro core or similar installations, no need to spend delta V on that (though the total amount you'd spend wouldn't be high anyway).

15 hours ago, Joerg said:

If you are in for long coasting, I maintain that Ion drives and assisted initial velocity is way more likely.

No issues with renting a rocket for "assisted initial velocity", but ion drives are complicated, extremely low thrust and power hungry. See above.

15 hours ago, Joerg said:

I think that the fission-reactor powered atomic rocket will be built for interplanetary travel until ship-sized internal fusion reactors become available.

Right now, the big money is on chemical rockets.

15 hours ago, Joerg said:

Otherwise, passive drives (light sails) are going to play a role

For unmanned ships with unlimited time and as long as there is no FTL (which seems likely, though), perhaps.

53 minutes ago, prinz.slasar said:

In the setting ELEVATION for M-SPACE there are some rough assumptions for fuel and transport ranges.

The starships in this setting are fueled by Nebulium.

1. The nebulium orbs losing 3 grams of material for every LY the wormhole stretches. [p 42]

2. The fuel is enough for a travel up to 800 light years before the nebulium needs refueled [p 16]; the more grittier version of the setting reduces this to 5 wormholes at maximum jump distance.

3. ELEVATION adds fuel values to the hyperspace stat of its starships: hyperspace 1 [fuel for 100 LY per jump], hyperspace 2 [fuel for 400 LY per jump] and hyperspace 3 [fuel for 800 LY per jump]

 

 

But that is for the FTL side of things. That's "magic" anyway, so one can easily make up any number one likes. Which is cool, but not helping with the question.

Quote

I feel that the request is similar to a game about modern navy warfare to provide the logistics for trireme sailing.

Well, one could argue that a generic SF RPG should include support for more than one type of SF setting. Besides, it doesn't only lack chemical rocket fuel but also fusion rocket fuel, antimatter rocket fuel, even just reactor fuel for the average magic space drives. I had hoped someone might have done some work there. No problem if that isn't within the system's abilities, I'll just import a design system from another source.

Quote

What kind of chemical fuel were you thinking about, anyway?

Hydrogen, methane, kerosene or hydrazine, combined with liquid oxygen. Enough to give a ship a few thousand m/s of delta v. If you want faster travel than what this will allow for, use the FTL drive. If you don't have one, coast a lot, and do swing-by maneuvers, and possibly use the Oberth effect to your benefit.

Of course, in such a universe, space battles are boring artillery duels with little to no actual tactics once the shooting starts.

Quote

Without artificial gravity, deck plans only make sense Expanse-style, with vertical ship designs. Rotating habitat rings need to slow down for course alterations and don't make sense for warships (sorry, Babylon 5 Terran Fleet) due to gyro effects (unless brutally used as gyros, which makes them unusable as habitats, at least during maneuvering).

There are centrifugal artificial gravity system ideas that do work better, like rotating the entire ship along one axis, or enclosed centrifuges that are encased in stationary armor on the outside, or even using tethered fuel tanks as counterweights to rotate around a common center of mass with the main ship (this is particularly useful for ships in the classic "player ship size" range). As your chemical rocket ships ( I maintain they are the most likely ship to ever actually be built in significant numbers) coast a lot anyway, having to stop rotation for a while while changing course isn't a big deal, because  you won't do that often.

32 minutes ago, Joerg said:

Fuel and/or reaction mass consumption isn't part of the M-Space ship design.

That was indeed my impression, but that's disappointing. Fuel is THE big issue with spacecraft.

Well, then I'll just have to use GURPS Spaceships, converted to metric. The stats will work with BRP with only slight conversion, I believe.

15 hours ago, Joerg said:

 chemical rocket drives are extremely rare as they have bad exhaust temperatures/velocities compared to plasma - whether electromagnetically, direct fusion exhaust, or other such means. Then there are ion drives, gouvod for long term acceleration at low thrust rates, like system insertions to aid solar sail braking, or possibly braking by collecting solar wind with a buzzard ramjet.

Maneuver drives using chemical drives or "going teakettle" exhausting e.g. superheated steam or a hot flame might be useful in those applications, but the reaction mass to acceleration ratio is simply abysmal.

[...]

Given the heating and power problems all the alternatives produce, chemical rockets still are the best option for almost any application , even IF we ever solve the fusion problem on the ground. For a campaign of mine, I created an entire galactic setting where even the most advanced civilizations use chemical rockets, because the advantages of all the other systems aren't just worth the complications - but that was with a different system. (And yes,that implies renting rockets to lift you into space at the spaceports.)
But yes, it's terribly hard to do space travel. That's a given.

Anyway, does anyone have stats for fuel tanks (be they for chemical drives, fusion rockets, ion engines or whatever) for use in M-Space? I can do the math myself, but before I spend time on that, I'll rather check out what all the other people did.

Or do you guys just wing it? (But then, why bother with a spacecraft design system at all?)

M-Space has spaceship construction rules, but they do seem to be lacking fuel tanks... which is particularly sad if you wish to use chemical rockets or even hard SF reaction drives in your setting.

Has anyone done any work on this in order to get good numbers of Delta V and fuel percentage out of the M-Space spaceship construction system?

Thanks for the hint!

On 6/27/2019 at 8:14 PM, lawrence.whitaker said:

Drugs.

Soporifics to keep the magician sedated or too woozy/spaced-out to cast effectively, coupled with effective restraints for hands and tongue. 

A bit outside the box, but it makes sense... I've added a plant to my setting whose sap eats away the drinker's magic points. Thanks!

16 hours ago, Matt_E said:

Use Passive Possession by a spirit that constantly shrieks (or sings Britney Spears tunes, or whatever).  Treat as a form of ongoing Miasma that combines aspects of the spells Befuddle and Demoralize.  After a suitable amount of time, the victim develops the Passion Madness.  This nefarious treatment combines punishment (torture, really) and restraint.  They might kinda like Loz's narcotics...but they won't like this.

 

For punishing the most evil (by the rulers' definition) people! Thanks for this idea!