[Spaceships] Drive economics

[Ulzgoroth]

Originally Posted by AlexanderHowl

The 1.5% includes the normal maintenance costs of good quality spaceships. It is talked about in Spaceships 2.

Yes, if you're working out of the box titled 'fudging it'. EDIT: And the option within that box labeled "Ignore everything".

And that 1.5% replaces all expenses whatsoever.

[AlexanderHowl]

Except for the additional maintenance for cheap and very cheap spacecraft (that is added to the 1.5%). Of course, it is an approximation, but it is an economically plausible approximation, and I always use it in my settings to determine economic feasibility of space operations. In addition, you need to account for reaction mass costs, ammunition costs, and a reasonable profit (if a commercial spaceship). If a $600M merchant ship burns through $100M in missiles a month and/or through $100M in reaction mass a month, the 1.5% is not a major expense.

[Ulzgoroth]

Originally Posted by AlexanderHowl

Except for the additional maintenance for cheap and very cheap spacecraft (that is added to the 1.5%). Of course, it is an approximation, but it is an economically plausible approximation, and I always use it in my settings to determine economic feasibility of space operations. In addition, you need to account for reaction mass costs, ammunition costs, and a reasonable profit (if a commercial spaceship). If a $600M merchant ship burns through $100M in missiles a month and/or through $100M in reaction mass a month, the 1.5% is not a major expense.

The only place I can see 1.5%, you do not in fact account for reaction mass or ammunition additionally. It is the "ignore everything" option. I see no reason to think it is economically plausible to any significant extent.

However, if you want to treat it as a meaningful data point, you should probably bear in mind that that 1.5% drops to 0.5% if you aren't paying off loans on the ship.

[Rupert]

Originally Posted by AlexanderHowl

Except for the additional maintenance for cheap and very cheap spacecraft (that is added to the 1.5%). Of course, it is an approximation, but it is an economically plausible approximation, and I always use it in my settings to determine economic feasibility of space operations. In addition, you need to account for reaction mass costs, ammunition costs, and a reasonable profit (if a commercial spaceship). If a $600M merchant ship burns through $100M in missiles a month and/or through $100M in reaction mass a month, the 1.5% is not a major expense.

That 1.5%/month expense in 'Fudging it' includes financing, crew costs, the lot. Without finance it's 0.5%/month. If we look at the Kiev-class (SS2, p.6) that 0.5% is about $700K/month. It has nine crew and is 3,000 tons, so we have a Rank 2, a Rank 1, and seven Rank 0 crew. As the ship is TL10^ the crew salaries come to $78.4K/month. Feeding them is cheap enough we can forget about it, and reaction mass (water) isn't much more unless she's being refuelled pretty much daily. So in this case you could assume that a little under 0.5%/month is the maintenance cost of a new ship.

But what about a Titan-class? The reaction mass alone is nearly 2% of the ship's cost, so unless she only refuels less often than every four months (possible, but not guaranteed) that's the fudged monthly cost used up right there.

Oh, another reason to dislike 0.5%/month for 'new' ships - that's the same annual maintenance cost as a 'cheap' ship has (1%/month but of the 1/2 price cost). That makes buying a new ship a mug's game - monthly costs as a 'cheap' ship, and unless 'cheap' goes to 'very cheap' quite rapidly there's as much or more depreciation on the new ship as on the older 'cheap' ship. Both new and cheap ships should make economic sense, but in different situations.

[AlexanderHowl]

In reality, the liability insurance alone for a spaceship should be at least 0.5% of its new cost per month. For example, a SM+10 spacecraft that rams a SM+14 station at 0.1 mps deals 6d×45 d-damage (an average of 945 points of d-damage) to itself and the station. The spacecraft is utterly destroyed and the station suffers the destruction of two components, and that is just a 0.1 mps collision.

The cost of repairing the station, replacing the spacecraft, lost income, and compensating the victims (or the families of the victims) will probably average $10B (since insurance companies want to hedge and make a profit, it will end up increasing premiums by $12B). If it occurs in 1:4,000 ship-months, that would be an insurance cost of $3M per month for a SM+10 spacecraft (0.5% per month). Basically, a SM+10 spaceship would be expected to have a minimal collision once every 330 years of operation.

[Fred Brackin]

Originally Posted by AlexanderHowl

I. For example, a SM+10 spacecraft that rams a SM+14 station at 0.1 mps deals 6d×45 d-damage (an average of 945 points of d-damage) to itself and the station. The spacecraft is utterly destroyed and the station suffers the destruction of two components, and that is just a 0.1 mps collision.

What I get out of that is that ships aren't going to be allowed anywhere near space stations at 0.1 mps. Even if that was meters per second and not miles (why I dislike the "mps" abbreviation) they'won't be moving under their own control.

Part of this is the grotesque scale that creeps into our assumptions. SM+10 is a rather large naval warship or about 50 jet airliners. Of course that makes a mess when it hits something.

[DaltonS]

Originally Posted by Fred Brackin

What I get out of that is that ships aren't going to be allowed anywhere near space stations at 0.1 mps. Even if that was meters per second and not miles (why I dislike the "mps" abbreviation) they'won't be moving under their own control.

Part of this is the grotesque scale that creeps into our assumptions. SM+10 is a rather large naval warship or about 50 jet airliners. Of course that makes a mess when it hits something.

Not to mention 0.1 miles/second is 360 mph which is a substantial clip.

Dalton “Can you say "Ouch!"?” Spence

[Tyneras]

As Issac Arthur often says, realistic space stations will likely be massively armed and armored fortresses, not fragile Christmas ornaments as they are usually depicted in visual media. The ship would likely be crashing not into a SM+14 space station, but the SM+15 or SM+16 station surrounding it that's almost nothing but "armor" (raw material storage) and some weapons, sensors and communication systems.

This is how I've taken to designing my stations, wrapping them in a much larger stations that's mostly warehouse and armor and some defense.

Still, traffic control will be pretty important.

[Ulzgoroth]

Originally Posted by Fred Brackin

What I get out of that is that ships aren't going to be allowed anywhere near space stations at 0.1 mps. Even if that was meters per second and not miles (why I dislike the "mps" abbreviation) they'won't be moving under their own control.

Part of this is the grotesque scale that creeps into our assumptions. SM+10 is a rather large naval warship or about 50 jet airliners. Of course that makes a mess when it hits something.

That's not really grotesque. Real cargo ships are big. If space cargo ships exist at all, they will probably be big too - for some overlapping reasons.

Originally Posted by DaltonS

Not to mention 0.1 miles/second is 360 mph which is a substantial clip.

Dalton “Can you say "Ouch!"?” Spence

It's a substantial clip, but it's also going to take a lot of time to traverse any distance that isn't astronomically negligible.

Though a few tens of miles of safety radius would certainly do a lot to limit accident risks while not taking egregiously long to traverse.

Originally Posted by Tyneras

As Issac Arthur often says, realistic space stations will likely be massively armed and armored fortresses, not fragile Christmas ornaments as they are usually depicted in visual media. The ship would likely be crashing not into a SM+14 space station, but the SM+15 or SM+16 station surrounding it that's almost nothing but "armor" (raw material storage) and some weapons, sensors and communication systems.

This is how I've taken to designing my stations, wrapping them in a much larger stations that's mostly warehouse and armor and some defense.

Still, traffic control will be pretty important.

Every real space station that has actually existed is unrealistic? I think there's a missing context maybe?

[Anthony]

Originally Posted by Tyneras

As Issac Arthur often says, realistic space stations will likely be massively armed and armored fortresses, not fragile Christmas ornaments as they are usually depicted in visual media.

Eh, that depends heavily on other constraints. The simple solution to accidents is just putting the docking area on one or more long spars, and armor sufficient to handle deliberate enemy action tends to be impractical.