Does Interstellar Trade Make Sense For Realistic Science Fiction?

[AlexanderHowl]

I do not think that a spacecraft without armor on its sections will be capable of gaining insurance at any reasonable rate and I also doubt that a bank would be willing to give a loan for a spacecraft without any hull. Even Stone Armor would be better than nothing from the point of view of an insurer or a lender, though I would think that most insurers and lenders would give better rates to the spacecraft with better armor (all other things held constant).

[Ulzgoroth]

Originally Posted by AlexanderHowl

I do not think that a spacecraft without armor on its sections will be capable of gaining insurance at any reasonable rate and I also doubt that a bank would be willing to give a loan for a spacecraft without any hull. Even Stone Armor would be better than nothing from the point of view of an insurer or a lender, though I would think that most insurers and lenders would give better rates to the spacecraft with better armor (all other things held constant).

Why? Having a minimally armored hull provides essentially no protection against anything that can actually threaten the ship.

TL11 freighters with 1 layer of steel armor don't have it because it actually provides useful protection, they have it because they're designed on a tradition that ships are not thin-skinned.

[AlexanderHowl]

A dDR 50 protects completely against a 10 MJ laser or protects somewhat against a low velocity collision (0.1 mps) with a small spacecraft, which is better than nothing from the point of view of a lender or an insurer.

[Rupert]

Originally Posted by AlexanderHowl

In reality, the cost to operate a spaceship should probably be around 2.5% of its cost per month. A TL11^ Free Trader costs $94.3M, so it should cost $2.36M per month to operate. Since it has a cargo capacity of 300 tons, it should probably cost $10k per month to ship anything, since the owners will want to make a profit.

Your choice of 'free trader' is one that's really not going to make money on routine flights - it's the the Millennium Falcon by another name, and so it's way more expensive than a sensible cargo ship, and has rather less carrying capacity.

If you use the Anthem-class instead, at $25.9M and 450 tons of cargo capacity things will look much better. Also, that very expensive trader you chose should be doing three times the speed in hyperspace, though that won't improve things much for it (see below).

If we assume that it takes one day to leave the hyperspace exclusion zone, one day to travel through one parsec of hyperspace to a new system, and one day to travel from the hyperspace exclusion zone to the destination, the minimum travel time for short journeys is 3 days, around 10/month. That would suggest a minimum cost for interstellar transportation of $1,000 per ton, but the suggested rate in Spaceships 2 is $10 per parsec, which would bankrupt any owner within a year. The passenger rate would be 10x the cargo rate.

That's about the most expensive trip, per parsec, that you can make, because the normal-space component at each end won't vary as distance does. If the trip is 20 parsecs, the cost per parsec would be around $370/ton, for example.

Using the Anthem and your 2.5%/month cost and your profit margin, each ton of space has to make ~$2750 per month. Assuming an average flight of 10 parsecs, one day in-system at each end, and a 2-day turnaround, and thus two trips a month, each ton needs to earn $137.5 per parsec.

Passengers do not need to cost ten times as much. A 'cabin' consumes 7.5 - 8.33 tons, and can carry a luxury/first-class passenger or two normal passengers. The weight of consumables is 4 pounds per passenger per day, and costs $2/day ($20/day for a luxury passenger). The stewards are probably the biggest cost and weight, at one per two luxury, five 1st class, or 20 normal passengers (plus their accomodations, etc.). A normal passenger is about 5 tons worth of cargo lost, a 1st class about 10, and a luxury passenger about 12. Even gourmet rations for high-paying passengers are a minor cost compared to the transport cost of their tonnage, and a luxury passenger probably should pay about $1850/parsec, a 1st class about $1500, and a normal passenger ~$700. That includes their share of the steward's wages, etc., BTW.

So, using the ships in the book, it's not nearly as bad as you suggest, and with really bare-bonus ships (especially larger ones, so minor system like a few shuttles or whatever take up a smaller percentage of the mass) costs can drop even more.

Oh, and you left out the cost per AU that's normally charged for normal space trips (so did I), though they're really negligible anyway.

[Rupert]

Originally Posted by AlexanderHowl

A dDR 50 protects completely against a 10 MJ laser or protects somewhat against a low velocity collision (0.1 mps) with a small spacecraft, which is better than nothing from the point of view of a lender or an insurer.

Modern ocean-going freighters have relatively thick hull to survive wave action and hull flexing, not to protect them from collisions. I have no idea why an insurer would want a million-ton freighter to devote 150,000 tons to armour - that's more than most warships in the 19th and 20th century put into armour (only battleships and battlecruisers, and a few cruisers), and you're talking of covering the thing with 7" of steel. Even 5% using the various 'small system' and 'spread armour' rules seems excessive.

It's far more than you need for micro-meteor protection, far less than you need for any serious collision, and reduces the ship's revenue gathering capacity by ~17%.

[Ulzgoroth]

Originally Posted by AlexanderHowl

A dDR 50 protects completely against a 10 MJ laser or protects somewhat against a low velocity collision (0.1 mps) with a small spacecraft, which is better than nothing from the point of view of a lender or an insurer.

Is it really?

Under what insured circumstances are you going to be taking 10 MJ laser hits but not anything else that means your ship is doomed?

And an SM+5 ship collision at 0.1 mps is (A) something very unlikely and (B) going to do ~126 dDamage - that's going to cause serious damage with or without DR 50. Maybe the repair payout is a bit smaller, if nothing goes further wrong, but you're eating a huge expense.

[RyanW]

It looks like you're using the Dark Horse from SS2. If so, using that as your basis of comparison is akin to basing a calculation of international trade on the cost to operate drug cartel go-fast boats.

To maximize revenues, you want your equipment operating as continuously as possible. Have interface craft hauling cargo to and from the edge of the hyperspace exclusion zone, where the big ships just drop out of hyperspace, drop off their cargo containers, pick up the next batch, and leave. Why waste so much effort hauling hyperdrives up and down gravity wells?

[weby]

Originally Posted by AlexanderHowl

I do not think that a spacecraft without armor on its sections will be capable of gaining insurance at any reasonable rate and I also doubt that a bank would be willing to give a loan for a spacecraft without any hull. Even Stone Armor would be better than nothing from the point of view of an insurer or a lender, though I would think that most insurers and lenders would give better rates to the spacecraft with better armor (all other things held constant).

Armor is not hull in the Spaceships system, it is additional protection. And why would you need to build to warship standards to get insurance? Having 15% to armor is like a car insurer requiring you to add 300lb steel plates to your car to give good insurance rates.

If you are in a situation where it is common to be attacked and thus need armor and weapons, then you are not looking at normal base shipping rates, you are looking at the wartime rates.

[David Johansen]

Originally Posted by Ulzgoroth

Only an advantage if you lack other means of living further into the future or relativistic travel is cheaper than your costs of living...

The thing about it is that you've essentially gone forward in time and skipped a lot of stuff. I heard an insurance adjustor explaining that their math says that even if we were immortal and free from disease nobody would make it past two hundred. The odds just catch up to you.

Compound interest is exponential. If you didn't come back filthy rich it just means you didn't stay away long enough. Or your bank failed or society collapsed while you were gone or the communists won or inflation went crazy because too many people went away and came back just like you did.

Alternately you can fill your ship with the things you'll need to rebuild civilization and wait until it collapses to come back. DGP's AI used this premise.

[Andreas]

Originally Posted by David Johansen

The thing about it is that you've essentially gone forward in time and skipped a lot of stuff. I heard an insurance adjustor explaining that their math says that even if we were immortal and free from disease nobody would make it past two hundred. The odds just catch up to you.

Then that insurance adjustor was very wrong. Even if you ignore the fact that some people are consistently more careful than others, and even if you live in a community dangerous enough that there is a 0.5% risk of dying to crime, accidents or suicide each year, then roughly 37% of people would survive past 200 years. Almost 0.7% would survive past 1000 years.

This is also ignoring factors such as hospitals becoming better at treating injuries and cars becoming safer etc.