d20 Future and Hard SF - some random thoughts

[kingpaul]

However there are some things that really are impossible, like 1+1 = 3.

False! One man + one woman = one man, one woman and 1+ children.

 

[Flynn]

Heim Theory

Not to throw a wrinkle in the discussions, but the Air Force is currently doing research on FTL travel based on Heim Theory:
http://en.wikipedia.org/wiki/Heim_theory

If it works, we could be seeing FTL ships within our lifetimes, or at least within those of our children.

Hope this helps,
Flynn

 

[crazy_cat]

Not to throw a wrinkle in the discussions, but the Air Force is currently doing research on FTL travel based on Heim Theory:
http://en.wikipedia.org/wiki/Heim_theory

If it works, we could be seeing FTL ships within our lifetimes, or at least within those of our children.

Glad you posted that. It made clear and concise reading and cleared up a few of the nagging concerns I had about the fundamental nature of the structure of the universe and of space-time. Not.

 

[EditorBFG]

So, in that almost year, you'd travel quite a good distance. Of course, I'm not sure what the distances are to the nearest stars are (besides the sun).

Star System Travel Time at 1C (the Speed of Light)
Alpha Centauri 1591 days (4 years 131 days)
Barnard’s Star 2164 days (5 years 339 days)
Wolf 359 2840 days (7 years 285 days)
Lalande 21185 3026 days (8 years 106 days)
Sirius 3132 days (8 years 212 days)
Epsilon Eridani 3840 days (10 years 190 days)
Procyon 4161 days (11 years 146 days)
61 Cygni 4161 days (11 years 146 days)
Epsilon Indi 4314 days (11 years 299 days)
Tau Ceti 4336 days (11 years 321 days)

This is hard science. I know, cause I got it from Cracked Mirror's McGuffin's Guide to Starship Construction.

Speaking of hard sf, for me the big step in making a recent space opera game believable was establishing that there would be no dogfighting starfighters-- at the speeds spacecraft would travel, they would have no way to hit each other. Any technology that made a missile faster could reasonably be applied to ships as well, meaning a missile would never catch a ship unless it slowed down to let it hit. I made the Defense bonuses for spacecraft speeds really high and that seemed to do the trick.

 

[DarkKestral]

However, let me play the skeptic about Heim theory: The military has repeatedly researched the possiblity of ESP, telekinesis, and other 'magical' or 'psionic' abilities. None of the efforts demonstrated conclusively evidence of any of them. Therefore, military research is not always the best predictor of a theory's validity.

 

[Mustrum_Ridcully]

Any technology that made a missile faster could reasonably be applied to ships as well, meaning a missile would never catch a ship unless it slowed down to let it hit

Unless the ship contains a human passenger, in which case a ship's maximum safe acceleration is severely limited. The missile would also have the advantage of being smaller/having less mass(it only needs a warhead, engine and a tracking system, while a ship or drone would probably need additional systems - like a missile launcher for combat, life support for a crew, storage facilities for freight, data storage, sensor system, possibly atmospheric landing equipment and so on).
Which is probably an argument for drone combat, since these can be highly specialised for their task. Any non-drones will need drones to defend themselves.

Ships accelerating to near-light speeds doesn't mean they do it fast - if it takes 5 years to reach Alpha Centauri 2 years of acceleration and 2 years of acceleration seems relatively acceptable. Which would mean that space combat wouldn't need to take place at such high speeds...

 

[DarkKestral]

Yeah, one of the advantages of missile weapons is that their acceleration can be so much higher than the equivalent for humans. 12+ Gs are acceptable for missiles, while the same to a human over a significant timeframe is deadly. 1-2 Gs is perhaps the max. Additionally, missiles are great in that they don't have to decelerate: hitting the target at high enough speeds can be just as effective as actually detonating an explosive warhead. Perhaps more effective; meteorites can produce craters and explosions more powerful than any current nuclear device, and they aren't going much more than maybe .3-.4 C, and a missile at .99 C might be able to obliterate significant areas from energy transfer alone, and the resulting shockwaves would probably rip anything that survived the initial collision apart.

 

[EditorBFG]

Unless the ship contains a human passenger, in which case a ship's maximum safe acceleration is severely limited. The missile would also have the advantage of being smaller/having less mass(it only needs a warhead, engine and a tracking system, while a ship or drone would probably need additional systems - like a missile launcher for combat, life support for a crew, storage facilities for freight, data storage, sensor system, possibly atmospheric landing equipment and so on).
Which is probably an argument for drone combat, since these can be highly specialised for their task. Any non-drones will need drones to defend themselves.

Ships accelerating to near-light speeds doesn't mean they do it fast - if it takes 5 years to reach Alpha Centauri 2 years of acceleration and 2 years of acceleration seems relatively acceptable. Which would mean that space combat wouldn't need to take place at such high speeds...

This all sounds sensible, I don't have as much of a scence background as I might like so I certainly acan't think of anything to refute that. I'm not sure I'm sold by the space combat not taking place at high speeds argument, even .1 C is *fast*. Are the physical effects of acceleration the same in space as they are within the gravity of a planet?

Given all your points though, there would not be any dogfighting. You'd fire missiles as soon as you detected a hostile, and if your opponent does the same, doing a barrel roll or whatever when the missile is going that much faster than you isn't going to do a lick of good. So it sounds like sf movie style space dogfighting is either impossible or suicidal.

Hard sf would not involve "starfighters," as it were.

 

[DarkKestral]

This all sounds sensible, I don't have as much of a scence background as I might like so I certainly acan't think of anything to refute that. I'm not sure I'm sold by the space combat not taking place at high speeds argument, even .1 C is *fast*. Are the physical effects of acceleration the same in space as they are within the gravity of a planet?

...

Hard sf would not involve "starfighters," as it were.

Yeah, they're the same. You feel heavy, and feel like being pressed down away from the direction of travel. Basically, high G acceleration feels like being on a high-grav planet, because gravity causes acceleration, and our unit of gravitational strength stems from the measurement of that acceleration. Mind you, it's not hard to have high-C travel with low G acceleration. Ion drives can do that pretty effectively, and you'll be up to a few tenths of C within a few years, and keep accelerating until halfway through the trip. This means that for long trips, you can actually get to .99 C or better speeds, assuming you can keep the ship together at that kind of speed, since any impact will prove to be significant at that speed.

This actually makes starfighters somewhat reasonable, as starfighters wouldn't be used on 'ships of the line' but rather as point-defense units for planets, space stations, and the like against pirates and groups who can't or don't want to destroy their targets by long-distance bombardment.

Thus, they might be designed for in-atmosphere work and as interceptor vessels designed for short bursts of high-G acceleration in order to get past larger ships for the sake of police work, providing a defense against close-range bombardment, or creating a blockade, since ion drives need a lot of maneuvering room to get up to speed.

Long-distance, however, would still be the choice of fleets who don't care about enemy casualties or who are actively hunting down vessels.

Mind you, this is not all THAT different from today: ICBMs are available, but militaries don't often use them in territorial conflicts because they are likely to create a 'scorched earth' situation which effectively ruins territory for both sides. Fighters and bombers are now used for the purposes of point attack on targets, blockading enemy states, and to as a defense for larger ships which may be vulnerable to attack from fast-attack vessels or weapons systems with a long range. Cruise missiles, while an upgrade in some respects from fighters, are useful when you want a larger attack, but not the all-out destruction of the type ICBMs are associated with. Carriers carry cruise missiles and fighters because they help provide protection from close-in aerial/ground-based retaliation.

 

[Mustrum_Ridcully]

This all sounds sensible, I don't have as much of a scence background as I might like so I certainly acan't think of anything to refute that. I'm not sure I'm sold by the space combat not taking place at high speeds argument, even .1 C is *fast*. Are the physical effects of acceleration the same in space as they are within the gravity of a planet?

Given all your points though, there would not be any dogfighting. You'd fire missiles as soon as you detected a hostile, and if your opponent does the same, doing a barrel roll or whatever when the missile is going that much faster than you isn't going to do a lick of good. So it sounds like sf movie style space dogfighting is either impossible or suicidal.

Hard sf would not involve "starfighters," as it were.

Movie style space dogfighting with manned ships is defintely unrealistic, but I doubt that many viewers would be interested in watching drone combats, therefore movies might never change that fact.