Examine my proposed FTL travel mechanics

[Minuteman37]

Originally Posted by Emerald Cat

The question that comes to my mind is "How do they eat?" Total life support eliminates the need for consumables. I'm still curious as to the duration of an interstellar flight.

Let's assume that we want the capability to travel 8 light years per jump. That may sound like a lot, but that only allows travel to Sol's 5 nearest neighbors. Hopefully, this will also make bottle neck systems rare.

Based on her length, the Millenium Falcon is a SM+8 ship. A ship that size would have a warp speed of 1 light year per 64 days. Making an 8 light year jump would take her 512 days = ~1.5 years.

That is a long time to spend in transit! And begs the question as to why anyone would bother with interstellar trade in universe. Unless the game is about the journeys between systems, I would personally go with much shorter travel times.

Simply multiplying your speeds by 5 goes a long way to solving this problem. Speed = 5/SM^2 light years/day. A SM+5 ship takes 40 days to travel 8 light years, an SM+8 ship takes 102 days, and an SM+10 ship takes 160 days. That gives a big advantage to smaller ships without making space travel prohibitively slow.

Oh yeah at this stage the FTL speeds are more for comparison between ships then anything else, I was considering mulitping them by 10 even.

The MS+8 ship was chosen for the smallest example becouse it is both in the ball park of the MF size and the smallest Size ship that can grow enough food to sustain the crew.

But given that 500 man days of food only takes up one system of cargo for a SM +5 ship for trips measured in months it's basically self-sufficient if cramped.

[Fred Brackin]

Originally Posted by Minuteman37

The MS+8 ship was chosen for the smallest example becouse it is both in the ball park of the MF size .

No it's not. In Spaceships terms the US Space Shuttle was unambiguously SM+6 without its' external tank and boosters. A 747 is SM+7 (by mass which is how Spaceships measures things) and an SM+8 is 3x as big as that 747 and 10x as big as a Space Shuttle.

Your travel speeds look too slow for anything truly MF sized. Your big ships will be worse. that SM+15 ship will be doing barely 50% faster than light. Even that minimal SM+8 (which is an ocean-going vessel rather than a Millenium Falcon type flier) is only doing 6x light. That's _years_ to anywhere and quite possibly decades to any Earth-like world.

You could get lucky and Alpha Centauri (A or B but not C so much) could have an Earth-like planet but after that there might be as few as 4 more candidate stars within 40 light years (based mostly on age but also taking in star-type).

A calculation I did with the system generation rules from Space 1e led to "natural" Earth-like worlds being c. 100 light years apart and even vaguely terraformable ones about 60.

So first decide how far destinations are apart. Then decide how long trips should be. _Then_ you have your answer about trip speeds. Don't start with a mathematical formula before you know if that's the answer you want.

Right now your speed numbers are too slow for anything much like a "small merchant" and no one will be able to afford to wait for whatever return a truly big ship could bring.

[Emerald Cat]

Originally Posted by Fred Brackin

A 747 is SM+7 (by mass which is how Spaceships measures things) and an SM+8 is 3x as big as that 747 and 10x as big as a Space Shuttle.

I looked this up, and yes Spaceships prefers mass. But you have to use length when you can't find the ship's mass. Or worse, base it off of the ship's capabilities/crew compliment.

[Emerald Cat]

Originally Posted by Fred Brackin

A calculation I did with the system generation rules from Space 1e led to "natural" Earth-like worlds being c. 100 light years apart and even vaguely terraformable ones about 60.

So first decide how far destinations are apart. Then decide how long trips should be. _Then_ you have your answer about trip speeds. Don't start with a mathematical formula before you know if that's the answer you want.

Right now your speed numbers are too slow for anything much like a "small merchant" and no one will be able to afford to wait for whatever return a truly big ship could bring.

Yeah, it is better to design your FTL drive to match the setting rather than the other way around.

[Fred Brackin]

Originally Posted by Emerald Cat

I looked this up, and yes Spaceships prefers mass. But you have to use length when you can't find the ship's mass. Or worse, base it off of the ship's capabilities/crew compliment.

Spaceships doesn't just prefer mass. It is based on mass alone. you have to have a hard mass for the realistic drives and their delta-v.

I know it's confusing for Spaceships to take a term from Basic and then use it for a completely different meaning but that's what it does.

You have to be very careful about "crew" too. The Millenium Falcon does say that it accommodates 2 crewmen and 6 passengers but if you look at the official deckplans you'll see that it accommodates those people in 2 bunkrooms. Traveller would assume 1 person, 1 stateroom and probably a fairly big stateroom too.

[Minuteman37]

Originally Posted by Fred Brackin

No it's not. In Spaceships terms the US Space Shuttle was unambiguously SM+6 without its' external tank and boosters. A 747 is SM+7 (by mass which is how Spaceships measures things) and an SM+8 is 3x as big as that 747 and 10x as big as a Space Shuttle.

Your travel speeds look too slow for anything truly MF sized. Your big ships will be worse. that SM+15 ship will be doing barely 50% faster than light. Even that minimal SM+8 (which is an ocean-going vessel rather than a Millenium Falcon type flier) is only doing 6x light. That's _years_ to anywhere and quite possibly decades to any Earth-like world.

You could get lucky and Alpha Centauri (A or B but not C so much) could have an Earth-like planet but after that there might be as few as 4 more candidate stars within 40 light years (based mostly on age but also taking in star-type).

A calculation I did with the system generation rules from Space 1e led to "natural" Earth-like worlds being c. 100 light years apart and even vaguely terraformable ones about 60.

So first decide how far destinations are apart. Then decide how long trips should be. _Then_ you have your answer about trip speeds. Don't start with a mathematical formula before you know if that's the answer you want.

Right now your speed numbers are too slow for anything much like a "small merchant" and no one will be able to afford to wait for whatever return a truly big ship could bring.

An SM+8 ship has a length of 50 meters saucer shaped ships can be anywhere from 50% to 75% of that length for the same given SM, the millennium falcon is 35 meters roughly speaking.

It's close enough for my tastes, the Tramp freighter of my setting will tend to average slightly larger then the Falcon.

As for scale I'm thinking of more then a dozen habitated systems, but certainly less then fifty. Devides among 7 for fewer factions. This game will be following the collapse of a great TL12 Interstellar Galactica human federation that would of teraformed any planet where that was feasible.

FTL communication isn't possible except for pony express style ships delivering data on high density storage devises, or single use exotic particles entangled at a Forerunner instalation that's fought over by the various factions, or use of telepaths (the setting includes Psi) so multi solar system governments are hard to keep under control but possible.

My new idea for the FTL speed formula is Ship SM -5 (minimum sm+6) squared in persecs.

Sound more plausible to you guys?

[Fred Brackin]

Originally Posted by Minuteman37

An SM+8 ship has a length of 50 meters saucer shaped ships can be anywhere from 50% to 75% of that length for the same given SM, the millennium falcon is 35 meters roughly speaking.

It's close enough for my tastes, the Tramp freighter of my setting will tend to average slightly larger then the Falcon.

My new idea for the FTL speed formula is Ship SM -5 (minimum sm+6) squared in persecs.

Sound more plausible to you guys?

"Length is only an approximation; feel free to vary it". That's the "important" part of the single paragraph about length in Spaceships. Still you're overestimating even based on that.

The official measurement for the Falcon is 26.7 meters rather than 35. That however, includes the "forks". If you subtract those and only look at the saucer you're going to be more like 20 making SM+7 more likely. I do mean "likely". Exact calculations based on length are not possible.

This is not to say that your small merchant ships should not be SM+8. However that is unambiguously 1000 tons of mass and 10x the size of the Space Shuttle and far bigger than the Millenium Falcon. You'll be misleading any players you have if you tell them it's the MF's size.

You still haven't gotten to the critical data for ship speed. Number of worlds doesn't matter. It's how long you want the trips to be and how far your ships have to go on trips of that length.

Your new formula (if I read it correctly) does increase your small merchant's speed from 6 light years per year to 40 but I still can't say if that's a useful speed.

It would make trips from Earth to a star 20 light years away 6 months out and 6 months back. In an astronomically realistic universe there won't be even a dozen habitable worlds in that volume. There might not even be one.

[Minuteman37]

Wookieepedia said 35 meters *shrug* lets not dwell on this.

The number of systems was given so you all could estimate the approximate size of the sphere of space this is set in. Though I am being an idiot becouse I already delt with the issue of making the setting too big with too many generic meaningless solar systems. You can't Travel to a system that lacks a warp buoy so I could literally just have 3 solar systems each on a separate edge of galaxy and none of the intervening space would matter.

Ideally I'm wanting an effect where Small fighterisk ships can buzz about from one neighboring system to another quick enough that it's not unrealistic for them to partake in the Journey, they may not be quite as small as X-wings for example and could have a sort of Truckers cabin besides the cockpit, but overall not comfortable for long travel.

Tramp freighters can make longer voyages and provide comfortable accommodations for a small crew + a few passengers and cargo, they're Journeys could take weeks without resupply.

The SM+10 ships are around the size of Corellian corvettes ( according to Wookieepedia they're 125 meters and I'm rounding down as the book says I can when trying to map fictional ships to the Spaceships system) and I envision them to preform Journeys with lengths much like sea going ships from the age of sail, a couple of months to go from England to Plymouth Rock for example, and do so in comfortable conditions for all the crew and passengers.

The massive SM+15 ships would be carries for many smaller combat craft, bulk transports for tons and tons of trade items, or colony ships. Journeys could take a couple of years but everyone would be living in the lap of luxury for the duration.

[Emerald Cat]

Originally Posted by Fred Brackin

"Length is only an approximation; feel free to vary it". That's the "important" part of the single paragraph about length in Spaceships. Still you're overestimating even based on that.

The official measurement for the Falcon is 26.7 meters rather than 35. That however, includes the "forks". If you subtract those and only look at the saucer you're going to be more like 20 making SM+7 more likely. I do mean "likely". Exact calculations based on length are not possible.

This is not to say that your small merchant ships should not be SM+8. However that is unambiguously 1000 tons of mass and 10x the size of the Space Shuttle and far bigger than the Millenium Falcon. You'll be misleading any players you have if you tell them it's the MF's size.

The problem is that sci-fi settings rarely give you the tonnage of their starships. Length is far more popular for indicating scale. Practically speaking, you need to use length when adapting fictional starships.

Regarding the Millenium Falcon, the Millenium Falcon falls between SM+7 and SM+8. I went with SM+8 because you're normally supposed to use the larger number when an object falls between SMs. I missed that line that you can round down when dealing with fictional spaceships. SM+7 does fit better.

When creating original ships, my approach to this is to derive the SM from length and then using the mass for that SM. I can visualize the ship's length. I can't visualize the mass. I don't see why we need to use mass as the starting point just because the system is based on mass.

[schmeelke]

The Dark Horse-Class Free Trader from Spaceships 2 (which is supposed to be inspired by the Millennium Falcon) is SM+8 and ST-v-SW.Net estimates the Millennium Falcon as being between 860 and 1720 tonnes, which puts it between SM+8.0 and +8.6.