Where this stands on scifi hardness scale

[Specter]

There wasn't a dedicated introduction section so I'll just say I'm from the southeastern US with an interest in writing and designing tabletop games.

I wanted to write the backstory for my game with a good understanding of how space really works. One of the first areas in my research was a wonderful site called Atomic Rockets and it turned out to be a gold mine of information! Shortly after diving head first into this I discovered a link to StarDestroyer.net which eventually lead me to this very forum. I have a natural aversion in joining forums of this caliber just to ask questions for reasons that some of you can already deduce without me going knee deep into it. I like to give the benefit of the doubt and my curiosity has overpowered my cautiousness. Let us hope the cliche of curiosity killing the cat isn't true in this sense.

The first considerations in mind is if I am serious about the background I will not try to "sell it" as hard science fiction because it is not. Not to say I'm going lockstep into the "rule of cool" (TV Tropes ahoy!) uber soft science fiction but there are some typical aspects of science fiction that we all know and love (or hate) I want to keep while maintaining some sane levels of plausibility. As much as I love Star Wars, many of us know spacecraft do not move in space like aircraft in atmosphere do. It is aesthetics such as that I want to avoid if it can be helped.

As it currently stands in this fictional universe starships travel through space in two methods: Conventional propulsion through various versions of plasma/ion fusion and a form of FTL travel. The FTL capabilities are not like Star Trek's warp drive where they simply push a button and they pop up somewhere. A lot of preliminary "pre-jump" calculations and storing enough energy for the quantum wave can take hours sometimes a day or two to complete. This makes military jumps very risky for they end up emerging right in the gauntlet of enemy defenses and have a reenactment of the Battle of the Dardanelles in SPAAACE!

Another aesthetic I love about Star Wars are huge starships slugging it out against one another like Spanish Galleons. As cool as it looks on film I doubt this is how realistic fleet engagements in space would work out. In my mind the opening salvos will be resolved in elaborate artillery duels a few thousands of miles apart with "long range" weapons such as kinetic energy weapons that can hurl metal slugs at blistering velocities. All the while the opposing ships are slowing down before the first shots are fired and by the time the ships enter a point blank range of a hundred miles or less from each other to execute combat maneuvers at velocities where planning new combat vectors are manageable without initiating long burns and delta-Vs. By this time the ships that survived the initial salvos are relying on the quality of their crews and defensive technologies to sway the battle in their favor. Most high intensity engagements happen within a thousand miles simply due to the lag time over great distances. Even the fastest projectile in this fictional universe takes 1 minute and 30 seconds to hit a target from a thousand miles away.

I hope this make some sort of sense so far. Not sure what else I need to mention at this time for those who want to gauge where this stands on the science fiction scale. Eventually what is said in the fluff will be reflected to some degree of accuracy on the crunchy side of the game.

[Mr Bean]

I'll comment more in the morning when I can type more coherently but when space combat comes up there's something you need to decide right off. Do you have artificial gravity? If no then your either building robot ships or putting a hard cap on accelerations because humans can't take an hour of 15 G accelerations. Sure the relative speed of engagements might be a .1 of the speed of Light but without artificial gravity your going to have to accept there shall be hard turns to port for dramatic effect without turning the crew into paste.

With artificial gravity your going have to decide how much. A series which does this well I'll admit is the Honor Harrington series because Weber pegs them as being able to compensate for so fast an acceleration he naturally gets how fast his ships go. Merchant ships ships can only accelerate at 200G-250 G's while big capital ships can do 400-500 G's and small ships can do 500+ G's.

To put those G numbers in context going from say 2 miles an hour (walking speed) to 10,000 miles an hour in 1 second is a 450 G acceleration. Going from 2 mile an hour to 1,000 miles an hour is 45 G's of acceleration and so on. Speed of light is 670,615,200 miles per hour so needless to say accelerating to lightspeed quickly requires being able to damp down a LOT of gravity.

So first decide how fast your ships move, how fast they can speed up, slow down and stop and combat will follow from that.

[biostem]

The FTL capabilities are not like Star Trek's warp drive where they simply push a button and they pop up somewhere. A lot of preliminary "pre-jump" calculations and storing enough energy for the quantum wave can take hours sometimes a day or two to complete. This makes military jumps very risky for they end up emerging right in the gauntlet of enemy defenses and have a reenactment of the Battle of the Dardanelles in SPAAACE!

This "quantum wave" drive will have to be so expensive that simply including a second "pre-charged" capacitor or battery for an immediate second jump isn't possible. Alternatively, it could be that such a jump inherently drains all power from the ship, and so they have to rely on a lot of mechanical secondary systems, until they can bring the main drive back online - maybe they actually carry a fission reactor to power up a fusion reactor, to in turn re-power the main engine/generator, which is what eats up so much time and leaves them so vulnerable.

Perhaps, because of these vulnerabilities, they actually send an automated ship ahead of them, which relies upon mechanical equipment to get the more complex computers back online, and those start prepping ahead of time, (perhaps such vessels run on minimal power, and make a lot of use of passive systems, like radar absorbant materials to keep them hidden). When the main ship jumps in, it could approach the prep-ship and simply transfer over its core, which was already charging, in the event of an emergency.

Building on the above, it could be that vessels are rated in their post-jump recovery time, with many factions employing much smaller craft that can recover much faster after such a trip - I wonder if, given these limitations, it would be feasible to directly charge the main drive via fission, since you can't drain uranium/plutonium/thorium, (or maybe they keep tanks of acid on board and dump it into battery tanks for immediate power after the jump).

[Specter]

I'll comment more in the morning when I can type more coherently but when space combat comes up there's something you need to decide right off. Do you have artificial gravity? If no then your either building robot ships or putting a hard cap on accelerations because humans can't take an hour of 15 G accelerations. Sure the relative speed of engagements might be a .1 of the speed of Light but without artificial gravity your going to have to accept there shall be hard turns to port for dramatic effect without turning the crew into paste.

With artificial gravity your going have to decide how much. A series which does this well I'll admit is the Honor Harrington series because Weber pegs them as being able to compensate for so fast an acceleration he naturally gets how fast his ships go. Merchant ships ships can only accelerate at 200G-250 G's while big capital ships can do 400-500 G's and small ships can do 500+ G's.

To put those G numbers in context going from say 2 miles an hour (walking speed) to 10,000 miles an hour in 1 second is a 450 G acceleration. Going from 2 mile an hour to 1,000 miles an hour is 45 G's of acceleration and so on. Speed of light is 670,615,200 miles per hour so needless to say accelerating to lightspeed quickly requires being able to damp down a LOT of gravity.

So first decide how fast your ships move, how fast they can speed up, slow down and stop and combat will follow from that.

There is artificial gravity mainly for the practical purposes of making crew lives tolerable and so they won't be splattered when the ship is making extreme maneuvers or torching their way out of the system's gravity well to make jumps.

If I must use a sense of scale because I'm horrible at math, the fastest patrol ship traveling on conventional drives can go from Earth to Mars in about four days. That is factoring in both acceleration and deceleration.

This "quantum wave" drive will have to be so expensive that simply including a second "pre-charged" capacitor or battery for an immediate second jump isn't possible. Alternatively, it could be that such a jump inherently drains all power from the ship, and so they have to rely on a lot of mechanical secondary systems, until they can bring the main drive back online - maybe they actually carry a fission reactor to power up a fusion reactor, to in turn re-power the main engine/generator, which is what eats up so much time and leaves them so vulnerable.

Perhaps, because of these vulnerabilities, they actually send an automated ship ahead of them, which relies upon mechanical equipment to get the more complex computers back online, and those start prepping ahead of time, (perhaps such vessels run on minimal power, and make a lot of use of passive systems, like radar absorbant materials to keep them hidden). When the main ship jumps in, it could approach the prep-ship and simply transfer over its core, which was already charging, in the event of an emergency.

Building on the above, it could be that vessels are rated in their post-jump recovery time, with many factions employing much smaller craft that can recover much faster after such a trip - I wonder if, given these limitations, it would be feasible to directly charge the main drive via fission, since you can't drain uranium/plutonium/thorium, (or maybe they keep tanks of acid on board and dump it into battery tanks for immediate power after the jump).

As a rule, any ship that is capable of having a jump drive will have a reactor big enough to supply energy to it. So far the smallest combat ship to be equipped with these drives are frigate class vessels and large interstellar merchant ships. Drives are usually half the cost of the entire ship itself and drives must be built proportionate to the ship's size and mass. All ships have secondary power units, this is just common sense. Going in or out of the quantum wave will be very visible on sensors and it does leave the ship vulnerable for a short time to re-calibrate instruments, bringing other systems online and the navigation crew getting its bearings. As much as people like to imply automation and AIs into this, they have a limited use in this fictional universe for a reason which I'm working into a plot device. So even if there was a lead ship making the jump first it cannot relay any warning to the ships behind it if it was in trouble because no communications is possible during a jump and long range communications are limited. So even you wanted to send a warning the ships behind the lead ship they will have to wait hours or even days until the message makes it through and by then the lead ship will be either destroyed or captured by the enemy.

For interstellar commerce jumps, a merchant ship capable of long range jumps (20+ light years) will go to a jump station or a buoy to be relayed their calculations to their nav-computer all the while their drives are storing energy for the wave formation after decelerating out of the gravity well. These drives have to be far enough away from a strong gravity well like from a star to "open" the wave. During transit intervening gravity wells won't collapse the wave unless it is directly in front of it from a miscalculation. Going around the gravity wells is akin to a surfer riding a wave, it is all about the momentum of the wave form and the energy behind it. Again I'm not a math major so running the numbers how this is possible is one of the reasons why I'm here because the people here are good at numbers.