Has anyone tried playing a career with infinite fuel?

[Zeiss Ikon]

An idea came to me this afternoon, concerning how small interplanetary spacecraft could be (even with a life support mod installed) with infinite fuel allowing constant boost.  A lot of science fiction has revolved around one or another kind of long-term constant boost (Larry Niven's ramscoop stories and Known Space, Doc Smith's Spacehounds of IPC, John W. Campell's Arcot, Morey, and Wade stories, several Heinlein "juveniles" involving torch ships -- and there are surely more).

Even in RSS, if you can boost from Earth orbit at a constant 1G and turn over halfway, you can get to the Moon in hours, Mars in around a week (at least when near conjunction), or even Neptune in a few weeks.  Spend a year without turning over and you're at a high fraction of light speed and, provided you have a means to avoid being wiped out by a microgram ice crystal, the entire "reachable" universe (around 18 billion light years radius) is within a reasonable travel time.  You wouldn't even need that much TWR to get to orbit; as long as you have about 0.3 it's enough to get off the runway (assuming you have enough wing lift), and then you can simply keep boosting as decreasing atmospheric pressure increases the efficiency of your engines.

Of course, there is the little issue of having to keep the game running in, at most, 4x physics warp through hours, days, or even weeks of boost time.  Is there a mod around that would let one use regular time warp while maneuvering, and/or closer to planets and moons than stock?  Needn't run at extremely high warp; to get several weeks into a few minutes is only 10,000x.

Alternatively, one might play with a burn time limitation -- is there a way to alter settings for one of the engine mods used in RO to allow engines to overheat after some set time, and then require a cool-down period?

[Kerbal4]

dude i did this at 13 G. i got past dres in a an hour and a half of high physics warp(6 kerbal hours), i kept going til lightspeed. it took ages but my kerbals had g limits off so they were fine. i also turned ignore max temperature on. 

[RizzoTheRat]

There's a mod called Better Time Warp that I believe allows you to warp at higher time multipliers while still thrusting.

As someone who calculates my own intercepts rather than using nodes, I'd hate to think how complicated the maths to work out an intercept with another body using this method.

[Fierce Wolf]

I gotta try a The Expanse approach of space faring, ships so powerfull they accelerate and desaccelerate all the time between origin and destination. It's doable with infinite fuel and cheating an engine to get 100-150 TWR

[DeadJohn]

On 1/25/2020 at 8:07 PM, Zeiss Ikon said:

Is there a mod around that would let one use regular time warp while maneuvering, and/or closer to planets and moons than stock?

See link for Better Time Warp below. It lets you go beyond the 4x of stock physics warp. I use it often and it's a great time saver.

Be warned that you increase the risk of glitches when you use physics warp. Save games before pushing things. My default physics steps with Better Time Warp are 1-2-5-10 times faster. 5x is generally reliable except during landing. 10x is safe in orbit, but Kerbals running on the ground can sometimes explode!

SAS maneuver-hold accuracy can suffer during physics warp so it's not perfect for precise aerobraking maneuvers, but it's close enough for intercepting planets.

 

[Zhetaan]

On 1/25/2020 at 8:07 PM, Zeiss Ikon said:

An idea came to me this afternoon, concerning how small interplanetary spacecraft could be (even with a life support mod installed) with infinite fuel allowing constant boost.  A lot of science fiction has revolved around one or another kind of long-term constant boost (Larry Niven's ramscoop stories and Known Space, Doc Smith's Spacehounds of IPC, John W. Campell's Arcot, Morey, and Wade stories, several Heinlein "juveniles" involving torch ships -- and there are surely more).

I know that Niven's ramscoops used what is essentially the most realistic equivalent of infinite fuel, because the fuel was not carried on the vessel.  Unfortunately, as I understand it, the interstellar hydrogen density figures that he had turned out to be wrong.  This is a common problem with hard science fiction:  you write a technology that you think is fantastic and someone invents it before the book is out, or alternatively, you build a world around an idea that current physics allows, only for someone to write a paper proving how it's actually completely impossible.

Arthur C. Clarke ran into something similar with his third Space Odyssey book; he wanted to wait for Galileo to visit Jupiter so he could use the updated data, but ended up writing the book anyway because the mission was delayed.  I mention him because he also used a variation of the torchship concept in that book.

I know that the Heinlein ships tended to use exotic (and fictional) atomic elements, and later models (the Vanguard from Orphans of the Sky and the New Frontiers from Methuselah's Children) used some kind of total conversion to get useful energy from small masses.  Niven's in-system ships were not ramscoops, but they did use magnetic confinement fusion to run under constant thrust and therefore qualify as torchships.  These could be better realised in-game as engines that use small amounts of an exotic propellant (or not so exotic; hydrogen is a real thing) to achieve amazing thrust.  Some of the Orion mods do that to simulate the bomb packages.

On 1/25/2020 at 8:07 PM, Zeiss Ikon said:

Of course, there is the little issue of having to keep the game running in, at most, 4x physics warp through hours, days, or even weeks of boost time.  Is there a mod around that would let one use regular time warp while maneuvering, and/or closer to planets and moons than stock?  Needn't run at extremely high warp; to get several weeks into a few minutes is only 10,000x.

It's not set up for the speeds you want, but look for light sail mods.  They are generally set up to include some method to allow for weeks of constant, low-value thrust to affect the trajectory calculation so that on-rails light sail craft still move as though they were not on rails.  I do not know whether the calculations would work for constant, high-value thrust; there may be a ceiling.  Mods that simulate orbital decay (I don't know whether RO includes any) might also provide a means to simulate constant acceleration in the form of negative decay, but that would probably be tied to proximity to a celestial body.  A constant-value acceleration that is not processed with proximity would be nice, but you may well need to write that yourself.

On 1/25/2020 at 8:07 PM, Zeiss Ikon said:

Alternatively, one might play with a burn time limitation -- is there a way to alter settings for one of the engine mods used in RO to allow engines to overheat after some set time, and then require a cool-down period?

The small ISRU works this way; it requires a certain amount of cooling, but it also includes a limit on cooling that is lower than the requirement.  The result is that it will automatically shut down if you don't pulse it manually.  The warp drive mods may provide a different means to do this, insofar as some of them require you to generate an exotic intermediary resource to power the drive.  If you limit the generation and storage of such a resource to the engine itself, then you could get a similar result without also requiring an insane number of radiators.

 

A lot of what you seek exists, albeit in scattered bits that may be well out of date.  You may spend more time collecting those pieces than you do using the result.  Nevertheless, good luck.

[Zeiss Ikon]

Thanks, @DeadJohn and @Zhetaan.  Better Time Warp is part of the puzzle (I might get that anyway, except that at present I'm playing a 1.6.1 RSS/RO/RP-1 and a 1.8.1 MH/BG stock game).  Having to find ways to import bits and pieces of this and that, however, seems like it's beyond what I have the time to learn to do, especially since it seems almost certain that at some point there'll be coding in C# or C++, neither one of which I currently have any proficiency in (getting started in modding looks like the equivalent of a 2-year college degree, at least from here). I might look into modifying engine configs to use tiny amounts of specific fuels, however.

I did launch a test vessel, the most basic version of this, in a 1.8.1 sandbox.  Mk.1 cockpit, tiny wings and a little fin, way-too-tall small retract landing gear, a tiny fuel tank (because apparently the game won't admit you have any fuel, even with infinite propellants, unless you have at least one tank), and a Spark, and flew it to orbit and through a reentry (saved from an overheated cockpit by turning over and using the engine to slow down).

Having done that, I think it might make more sense to look at the various warp drive mods.  I seem to recall one where the warp drive applied an acceleration, rather than just "pop, you're supraluminal" travel with what Doc Smith used to call "intrinsic velocity" conserved.

BTW, the other part of the ramscoop that Niven handwaved a good bit (or ignored) was the speed limit on any kind of jet: can't exceed its own exhaust velocity (unless you can avoid accelerating the incoming fuel/reaction mass as you collect it).  Niven wrote his ramscoops as doing this, at least in Protector and World Out of Time (don't think he went into detail about the  ships in The Leshy Circuit stories or Destiny's Road and Beowulf's Children, certainly not in Buidling Harlequin's Moon).  The limit I've read for Bussard Ramjets (effectively, the point at which scoop drag equals thrust) is about 12% c.  Too slow to be useful for anywhere further than the nearest planets in Known Space (Home, Wunderland, and Jinx, as I recall).  And Niven's handwave method of using the scoop itself to compress the interstellar medium to fusion density just won't work without accelerating the gas to ship speed.  Not to mention the fusion cross section of protium is apparently too low to get useful thrust.

Edited January 27, 2020 by Zeiss Ikon

[Zhetaan]

17 hours ago, Zeiss Ikon said:

(getting started in modding looks like the equivalent of a 2-year college degree, at least from here)

So says the one who wants to fly rocket ships along brachistochrone trajectories and do the rocket science that actual rocket scientists find difficult.

Seriously, though, I understand.  We all have our preferred cups of tea.

17 hours ago, Zeiss Ikon said:

BTW, the other part of the ramscoop that Niven handwaved a good bit (or ignored) was the speed limit on any kind of jet: can't exceed its own exhaust velocity (unless you can avoid accelerating the incoming fuel/reaction mass as you collect it).  Niven wrote his ramscoops as doing this, at least in Protector and World Out of Time (don't think he went into detail about the  ships in The Leshy Circuit stories or Destiny's Road and Beowulf's Children, certainly not in Buidling Harlequin's Moon).  The limit I've read for Bussard Ramjets (effectively, the point at which scoop drag equals thrust) is about 12% c.  Too slow to be useful for anywhere further than the nearest planets in Known Space (Home, Wunderland, and Jinx, as I recall).  And Niven's handwave method of using the scoop itself to compress the interstellar medium to fusion density just won't work without accelerating the gas to ship speed.  Not to mention the fusion cross section of protium is apparently too low to get useful thrust.

He handwaved, for the most part.  He actually did mention in a couple of places that the vessel could not exceed its own exhaust velocity (and he even included a few references to scoop drag), but he tied that velocity to that of the oncoming hydrogen--in other words, writing as though the scoop did not accelerate the hydrogen but nevertheless ignoring the fact that in order to bring hydrogen molecules together to fuse, it needed to do just that.  In The Ethics of Madness (which is emphatically not Niven's best scientific work, though I found the ethical debate interesting), the story concludes with two ramscoops chasing one another on autopilot for all eternity at almost the speed of light.

I think that Niven let the idea of infinite fuel get away from him and interpreted that as implying infinities (or near-infinities) in the other aspects of the ship design.  I think that he tended to view ramjets as something akin to streetcars in space:  the ramscoop slides along a stream of interstellar hydrogen and uses it for energy in the same way that a streetcar gets its energy from the overhead wires, but without considering the equally analogous notion that the streetcar is limited to the capacity of its motor--or, specifically, the ability of that motor to transform the energy into mechanical work--for its overall velocity.

17 hours ago, Zeiss Ikon said:

Having done that, I think it might make more sense to look at the various warp drive mods.  I seem to recall one where the warp drive applied an acceleration, rather than just "pop, you're supraluminal" travel with what Doc Smith used to call "intrinsic velocity" conserved.

In that case, I would think that it is really just a fantastically efficient or overpowered engine, which should be trivial to implement:  give a Rhino an I_sp of 340,000 and you'll be able to play with a torch drive until you get eye strain from watching the glow of the exhaust plume for too long.  The Rhino is the 'Size3AdvancedEngine' and the I_sp is given in the atmosphere curve under the thrust transform.  Since thrust is handled separately, adding three zeroes to the vacuum I_sp will only increase the fuel efficiency of the engine without making it into some kind of superluminal hyperdrive.  If you intend to use the stock Rhino (or already have it deployed elsewhere), then I suggest copying the file and giving it a new name.  You may decide for yourself whether you want to balance the cost or other factors, but for the sake of experimenting with it, I'd suggest letting those remain as they are.

[Zeiss Ikon]

4 hours ago, Zhetaan said:

So says the one who wants to fly rocket ships along brachistochrone trajectories and do the rocket science that actual rocket scientists find difficult.

If you have at least a large fraction of a G, brachistochrone is easy -- point at your target, boost, correct for target movement near turnover, then stern chase after stopping at the corrected location.  If your target's orbit is known, rough calculate trip time and boost for where the target will be.

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I think that Niven let the idea of infinite fuel get away from him and interpreted that as implying infinities (or near-infinities) in the other aspects of the ship design.  I think that he tended to view ramjets as something akin to streetcars in space:  the ramscoop slides along a stream of interstellar hydrogen and uses it for energy in the same way that a streetcar gets its energy from the overhead wires, but without considering the equally analogous notion that the streetcar is limited to the capacity of its motor--or, specifically, the ability of that motor to transform the energy into mechanical work--for its overall velocity.

Honestly, I think many of the physics errors in Known Space are the same ones other authors have made -- writing about stuff on the cutting edge, only to have the physics change -- and aside from fixing the Earth's rotation and retconning the rim engines in Ringworld, he kept everything else as it had been for the sake of continuity.  The first of the ramscoop stories (Protector, in order of publication) was published in 1967 (as The Adults).  Pretty sure most of what we now know won't work about a Bussard ramjet hadn't yet been thought out.

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In that case, I would think that it is really just a fantastically efficient or overpowered engine, which should be trivial to implement:  give a Rhino an I_sp of 340,000 and you'll be able to play with a torch drive until you get eye strain from watching the glow of the exhaust plume for too long.  The Rhino is the 'Size3AdvancedEngine' and the I_sp is given in the atmosphere curve under the thrust transform.  Since thrust is handled separately, adding three zeroes to the vacuum I_sp will only increase the fuel efficiency of the engine without making it into some kind of superluminal hyperdrive.  If you intend to use the stock Rhino (or already have it deployed elsewhere), then I suggest copying the file and giving it a new name.  You may decide for yourself whether you want to balance the cost or other factors, but for the sake of experimenting with it, I'd suggest letting those remain as they are.

I was actually thinking about doing that with something that runs on liquid fuel only (NERV), or modifying a RealFuels config for something to run on a unique resource, which RealFuels will let me put in a tank.