A note on starship design: the engines point down.

[Xavier Onassiss]

Steven Novella: In order to accommodate the odd ship design of having decks parallel to the direction of acceleration, while still allowing passengers and crew to walk around normally, science fiction writers have had to invent both artificial gravity and “inertial dampeners.” They need to provide a force of gravity perpendicular to the decks, and they need to eliminate the force of acceleration horizontal to the decks (accept when needed for some dramatic tossing around the bridge).

 

A more sensible ship design would be to have the deck perpendicular to the direction of acceleration, that way the force of forward acceleration would provide artificial gravity down into the deck. If such a ship were accelerating at 1G, then there would be no need for artificial gravity or inertial dampeners – you would not have to create gravity and eliminate acceleration – acceleration would be your gravity (thank you, Dr. Einstein).

 

There are also a few notes about this on Nyrath's page.

 

Does anyone here else do it this way?

[L. Marcus]

Re: A note on starship design: the engines point down.

 

Yah. I find it's the only sensible way to design Hard-ish Sci-Fi spaceships, at least with vessels with an acceleration in the 1/10th of a G and upwards.

[Vulcan]

Re: A note on starship design: the engines point down.

 

Yes, for a hard sci-fi game, perpendicular decks are the way to go.

 

HOWEVER, this imposes some rather severe design limitations of it's own. All of your decks are going to be quite small (unless you take the quite unusual step of making your ship spherical), which pretty much precludes large rooms, internal hangar bays, that sort of thing. Which is probably why most writers go with artificial gravity and inertial dampers, even if the rest of the story is hard sci-fi.

[Old Man]

Re: A note on starship design: the engines point down.

 

More to the point, perpendicular decks are contrary to the wet-navy or atmospheric-fighter conventions that most SF is shooting for. While more realistic, they are somehow harder for readers to get their minds around.

 

The only perpendicular-deck novel I can think of off the top of my head is Footfall, which is pretty hard SF; the only game system that I can think of that did that is Star Frontiers. Babylon 5 touched on it, but mostly as a way to show how technologically hopeless the Earthlings were during the Minbari War. By the time of the show, even Earth had artificial gravity tech.

[Vanguard]

Re: A note on starship design: the engines point down.

 

Never really had an interest in playing hard sci fi games. So no, I use artificial gravity and inertial dampeners.

 

Does cause issues when said systems get damaged but I tend to fudge it a bit so people aren't smushed against the bulkhead walls when that happens.

[Xavier Onassiss]

Re: A note on starship design: the engines point down.

 

More to the point, perpendicular decks are contrary to the wet-navy or atmospheric-fighter conventions that most SF is shooting for. While more realistic, they are somehow harder for readers to get their minds around.

 

The only perpendicular-deck novel I can think of off the top of my head is Footfall, which is pretty hard SF; the only game system that I can think of that did that is Star Frontiers. Babylon 5 touched on it, but mostly as a way to show how technologically hopeless the Earthlings were during the Minbari War. By the time of the show, even Earth had artificial gravity tech.

 

I tend to think SF readers can get their mind around this idea easily enough. Even if they've been spoon-fed a steady diet of "Hollywood" SF, odds are they've also seen footage of rockets lifting off from the Cape. It's pretty common knowledge (or at least it should be) how those work: no artificial gravity, and the G-forces from liftoff are directed downward.

 

The shuttle might confuse the issue a bit -- its decks are laid out "horizontally" so they're properly oriented on landing, but when it takes off, everything is sideways.

[dmjalund]

Re: A note on starship design: the engines point down.

 

It would have to a spacecraft with enough thrust to accellerate/decellerate through most of it's journey

[sinanju]

Re: A note on starship design: the engines point down.

 

Never really had an interest in playing hard sci fi games. So no, I use artificial gravity and inertial dampeners.

 

Does cause issues when said systems get damaged but I tend to fudge it a bit so people aren't smushed against the bulkhead walls when that happens.

 

Awww, c'mon! Where's the fun in that? It's cool to see the entire crew turned to jam when the inertial dampers fail while they're pulling 850 gees. (It's happened to a few warships in David Weber's Honor Harrington series, when battle damage destroyed the dampers. Characters in the series are aware of this possibility, but don't give it a lot of thought. If it happens there's nothing to be done about it. They'll be dead before they know it.)

[Xavier Onassiss]

Re: A note on starship design: the engines point down.

 

It would have to a spacecraft with enough thrust to accellerate/decellerate through most of it's journey

 

That's definitely the ideal option, but fortunately there are some other alternatives.

 

There are several of schools of thought on this: One is to make continuous acceleration a design requirement. Depending on the 'tech level' you're assuming, this may or may not be possible. Another option is to simply deal with the effects of zero-G when the ship isn't under thrust. If the voyage isn't too long, this won't cause any permanent harm. (It worked for the Apollo project.) Finally, you can use various methods to create spin-gravity when the ship isn't under thrust: spin the whole ship; use a tethered counterweight; tether two ships together and spin both; or use a centrifuge instead of spinning the whole ship.

 

The problem with a centrifuge is that it creates spin-gravity with "down" being at right angles to when the ship is under thrust. One way of dealing this is simply to not use the rotating centrifuge when the engine is firing. (This is kinda wasteful, tho.) Another is to design the spin-hull with sections that can re-orient themselves when the gravity changes. Various designs to accomplish this have been proposed. These are all covered in detail on Nyrath's website, of course.

[SSgt Baloo]

Re: A note on starship design: the engines point down.

 

In some of my Space-faring campaigns, propulsion was by a system I called "gravity slope generators". GSGs were electronically-controlled devices that could reorient and amplify the slope of space (gravity). Within a GSG field, the direction and strength of gravity could be wildly different than just outside. Everything inside the GSG field would fall in the same direction at the same rate, so a single field could not generate gravity.

 

If you used two GSGs, you would create two overlapping fields. The area of overlap would cancel out, but if your ship was designed to place half the mass in one field, pulling aft at one gee, and had the front half pulling in the opposite direction at two gees, you'd have a net thrust of one gee. Because of the difference in field strengths, objects in the forward decks would experience an apparent one gee in the direction of travel, and the aft decks would experience the same gee-force, but towards the aft.

 

Once the vessel has accelerated to coasting speed, each field is adjusted to maintain the one gee tug in each direction, with a net acceleration of zero. Steering is by intentionally directing each field in slightly different directions to rotate the vessel to a new heading. Actually, it's more complicated than that, but the ship can be rotated to orient in the desired direction and then thrust applied to alter its course.

[Xavier Onassiss]

Re: A note on starship design: the engines point down.

 

In some of my Space-faring campaigns, propulsion was by a system I called "gravity slope generators". GSGs were electronically-controlled devices that could reorient and amplify the slope of space (gravity). Within a GSG field, the direction and strength of gravity could be wildly different than just outside. Everything inside the GSG field would fall in the same direction at the same rate, so a single field could not generate gravity.

 

If you used two GSGs, you would create two overlapping fields. The area of overlap would cancel out, but if your ship was designed to place half the mass in one field, pulling aft at one gee, and had the front half pulling in the opposite direction at two gees, you'd have a net thrust of one gee. Because of the difference in field strengths, objects in the forward decks would experience an apparent one gee in the direction of travel, and the aft decks would experience the same gee-force, but towards the aft.

 

Once the vessel has accelerated to coasting speed, each field is adjusted to maintain the one gee tug in each direction, with a net acceleration of zero. Steering is by intentionally directing each field in slightly different directions to rotate the vessel to a new heading. Actually, it's more complicated than that, but the ship can be rotated to orient in the desired direction and then thrust applied to alter its course.

 

That's pretty cool. In my campaigns I usually do without artificial gravity tech, but this is an interesting idea.

 

I could see some variations on this: put a steady 1G field on the crew module, and have outriggers with paired opposing fields for maneuvering, mounted far enough from the main hull that the crew wouldn't be affected.*

 

*I hope that makes sense. I'm migraining pretty hard this morning.

[Outsider]

Re: A note on starship design: the engines point down.

 

Yes, for a hard sci-fi game, perpendicular decks are the way to go.

 

HOWEVER, this imposes some rather severe design limitations of it's own. All of your decks are going to be quite small (unless you take the quite unusual step of making your ship spherical), which pretty much precludes large rooms, internal hangar bays, that sort of thing. Which is probably why most writers go with artificial gravity and inertial dampers, even if the rest of the story is hard sci-fi.

 

Hm. Spherical ships seem like the logical starting option to me. You get the maximum enclosed space for the minimum material. A tendency towards 'cigar' shape would only come from a need to minimize the cost of direction-of-travel shielding, use in atmosphere, or structural issues involving transfer of impulse from the engines, depending on the engine tech.

[L. Marcus]

Re: A note on starship design: the engines point down.

 

Kinda sorta something like this. Apart from the cockpit placement, the decks are perpendicular to the axis of thrust.

[dmjalund]

Re: A note on starship design: the engines point down.

 

why not invent wide flat engines (that is - narrowest in the blast direction) after all, we probably aren't talking about spacecraft that have to be streamlined

[SSgt Baloo]

Re: A note on starship design: the engines point down.

 

The following two drawings were based on the above Dual-Opposed-Gravity-Field-Drive (DOGFD: DOGFooD). I designed them as part of a Star Trek universe that had a bunch of vessels I would like to have seen, but of course, I wasn't consulted throughout the various series' runs.

 

 

The Hephaestus was a prototype system defense ship. It's designed to patrol space near inhabited systems, supressing piracy, rendering aid to distressed spacefarers, and, when called upon, defending against invasion. The warp nacelles are uniquely-shaped to optimize them for use deep within a gravity well without unintended spacetime distortion (uneven time passage which will "weather" a spaceship's spaceframe, weakening it with microfractures). It's slower than other vessels outside of a stellar system, but within a stellar gravity well it can move at faster warp speeds without risk of damage.

 

The DOGFooD drive gives unparalleled maneuverability at sublight speeds, superior to impulse-based sublight drives. There is a sublight drive mounted aft, but it's primary purpose is to serve as an auxiliary power generation unit than additional propulsion.

 

 

The Lewis-class System Defense Ship was developed from the Hephaestus prototype. Major differences are the elimination of the former ship's "waist", providing extra room for auxiliary equipment, and the application of a layer of armor covered with a Distributed Integrated Multifunction Weapons, Sensor and Shield Array (DIMWSS), a hull coating with integral microstructures that provide phaser emitter, sensor, camouflage, and shield functions in a distributed array over the entire hull rather than as discrete emitters and recievers. Even when damaged, the system remains functional, though with lesser resolution (sensors and camouflage), power handling (weapons) and shield strength.

[tkdguy]

Re: A note on starship design: the engines point down.

 

I had to take it into account for my hard sci-fi campaign. Of course, that meant I had to change the aesthetics of my Orion Class ship from this to this.

 

Of course, I can still use the first design for more space operatic campaigns and during starship combat games (and I do).

[dmjalund]

Re: A note on starship design: the engines point down.

 

I had to take it into account for my hard sci-fi campaign. Of course' date=' that meant I had to change the aesthetics of my Orion Class ship from this to this.

 

Of course, I can still use the first design for more space operatic campaigns and during starship combat games (and I do).

you could have just changed the direction of the windows

[ClassifiedTSBBR]

Re: A note on starship design: the engines point down.

 

Kinda sorta something like this. Apart from the cockpit placement' date=' the decks are perpendicular to the axis of thrust.[/quote']

 

I was actually trying to reply to the thumbnail more than anything, sorry for my failure.

 

I'd actually suggest making the cockpick/bridge perpendicular to the thrust axis too.

 

If it's a cockpit, say it's under the darker circle on the lower front of the sphere (& move that forward & make it viewports).

 

If it's a bridge, replace the entire "front" zone with armoured viewports.

 

Either way, rather than having the crew seated at a console, have them in lying acceleration counches/beds.

 

Or just put the flight control center in the middle of the ship somewhere not bother with a viewport on the "front"/top unless it's for an observation deck.

[Cancer]

Re: A note on starship design: the engines point down.

 

Only in aircraft (and ground vehicles) has the command station been at or near the nose of the craft. In pre-steam ships it was always at the stern, and in steam and post-steam vessels it's generally amidships. Unless signal propagation times over the dimensions of the ship are important (or if you are so mind-bogglingly primitive as to use windows for seeing the edges of the craft during micromaneuvers) do you have any reason to put the command station anywhere in particular, modulo the requirements (or drawbacks) of other equipment.

 

The ship-gravity issue is part of the other considerations in the design of your sci-fi game world. Since you need approximately the Earth's present-day total power generation to accelerate a Space Shuttle class spacecraft continuously at 1 gee with a photon rocket, in the one sci-fi campaign I set up we presumed that accelerations were small, or an effect of the (handwave) star drive. Short-duration accelerations on the order of a gee were done using other drives (hydrogen-oxygen rockets, with the fuel slowly accumulated from the environmental systems; this implies a need to "water up" after any kind of violent maneuvering). If you decide your campaign's core tech issues in different ways, then you'll need different answers, of course.

[Kraven Kor]

Re: A note on starship design: the engines point down.

 

While not my first idea, I eventually moved to this for my more recent works.

 

Flying sky-scrapers, basically, with the bridge usually amidships - if the craft has viewports in the bridge, the bridge's seats will all be on gimbals so the crew can be comfortable while having a good view of everything. Most war ships don't have view ports and instead rely almost entirely on sensors and such, though most will have observers in several places in case sensors are not working for whatever reason.

[Kraven Kor]

Re: A note on starship design: the engines point down.

 

Though, I have often struggled with the whole deceleration part - would a craft having 1G acceleration and deceleration have the same gravity going either way?

 

As another idea I had would be ships that kind of had the decks set up so that any surface could be "down" depending on the state of acceleration - rotating sections for when not accelerating, then the one "wall" also being a floor when accelerating.

[Clonus]

Re: A note on starship design: the engines point down.

 

Steven Novella: In order to accommodate the odd ship design of having decks parallel to the direction of acceleration, while still allowing passengers and crew to walk around normally, science fiction writers have had to invent both artificial gravity and “inertial dampeners.” They need to provide a force of gravity perpendicular to the decks, and they need to eliminate the force of acceleration horizontal to the decks (accept when needed for some dramatic tossing around the bridge).

 

A more sensible ship design would be to have the deck perpendicular to the direction of acceleration, that way the force of forward acceleration would provide artificial gravity down into the deck. If such a ship were accelerating at 1G, then there would be no need for artificial gravity or inertial dampeners – you would not have to create gravity and eliminate acceleration – acceleration would be your gravity (thank you, Dr. Einstein).

 

There are also a few notes about this on Nyrath's page.

 

Does anyone here else do it this way?

 

I've designed ships with perpendicular decks, but it usually isn't an issue for me. Consider, that any non-fantastic ship capable of travelling for more than short orbital hops isn't going to have more than a miniscule acceleration anyway.

[Xavier Onassiss]

Re: A note on starship design: the engines point down.

 

Only in aircraft (and ground vehicles) has the command station been at or near the nose of the craft. In pre-steam ships it was always at the stern' date=' and in steam and post-steam vessels it's generally amidships. Unless signal propagation times over the dimensions of the ship are important (or if you are so mind-bogglingly primitive as to use [i']windows[/i] for seeing the edges of the craft during micromaneuvers) do you have any reason to put the command station anywhere in particular, modulo the requirements (or drawbacks) of other equipment.

 

The ship-gravity issue is part of the other considerations in the design of your sci-fi game world. Since you need approximately the Earth's present-day total power generation to accelerate a Space Shuttle class spacecraft continuously at 1 gee with a photon rocket, in the one sci-fi campaign I set up we presumed that accelerations were small, or an effect of the (handwave) star drive. Short-duration accelerations on the order of a gee were done using other drives (hydrogen-oxygen rockets, with the fuel slowly accumulated from the environmental systems; this implies a need to "water up" after any kind of violent maneuvering). If you decide your campaign's core tech issues in different ways, then you'll need different answers, of course.

 

In designing my campaign, I found that even extremely powerful rocket engines (terawatt-output fusion drives with exhaust velocity 8% of C at most) could only sustain 1G, or a significant fraction of a G, for a few days at most. So running the engines all the time to generate useful gravity doesn't work even for these types of rockets; most of the time they're cruising with engines off. The crew is in zero-G or using centrifuges.

[Kraven Kor]

Re: A note on starship design: the engines point down.

 

I've pretty much given up on 'rockets' as a viable drive for anything resembling fast space flight.

 

"Hard" or not, my current space craft concept is one that uses a gravitic drive - it basically uses a massive reactor to create a gravitational field to either push or pull the ship; then for FTL it actually bends space around it, creating a shortcut or "tunnel." The ship itself never reaches much more than a few % of lightspeed in actual velocity, but when in the tunnel you simply cross less space. As there are no FTL sensors, causality does not seem to be violated except in hindsight (ie, a telescope watching your journey might see you "arrive" before you "leave" but it is seeing the events years or hundreds of years after the fact.)

 

I still have some torch ships for in-system travel, mostly older ships from before FTL was possible in the setting, using high-efficiency Ion or Plasma drives driven by Fusion reactors; the reaction mass is the excess material from the fusion reaction.

 

In this setting, a journey from Earth to Alpha Centauri takes about 3 to 7 days depending on the age of the craft, while one to Xi Bootis - 38.x LY away - would take about 3 months.

 

As it seems you can't have FTL without Time Travel in a "hard" setting, I've decided to say heck with it, as you can't have interplanetary sci-fi awesomeness without FTL drives.

[dmjalund]

Re: A note on starship design: the engines point down.

 

Though, I have often struggled with the whole deceleration part - would a craft having 1G acceleration and deceleration have the same gravity going either way?

 

As another idea I had would be ships that kind of had the decks set up so that any surface could be "down" depending on the state of acceleration - rotating sections for when not accelerating, then the one "wall" also being a floor when accelerating.

the ship just flips.