[Spaceships] Million Merchant Marathon

[SydneyFreedberg]

Originally Posted by scc

... 2250. In that year Africa becomes unable to feed it's population due to poor environmental practices, this results in over a billion starving refugees fleeing the continent, this in turns causes other countries to have food supply problems and they all fall like dominoes. I wanted to figure out if there was any chance these terraforming projects could be advanced enough to supply food in large enough quantities to prevent this, the answer is no, which is fine with me. Note that this collapse doesn't effect the terraforming projects.

Wait. This civilization has enough ecological knowhow and energy to terraform multiple planets, but they can't prevent a food crisis on Earth, the one planet naturally habitable by humans and their food crops? For that matter, they can't control overpopulation in 2250, when UN demographers predict global population to peak around 2100* and fertility rates are already dropping, even in Africa, which has had the most births-per-woman on the planet**?

I understand the terraforming projects aren't far enough along to provide food or living space for people. But surely some of the underlying technology could be deployed to great effect on Earth -- to geoengineer away the impacts of global warming and other environmental mismanagement, for instance, or just to boost food production to keep up with population growth, or even to increase education & general welfare so people stop having so many babies (there's a particularly strong correlation between improvements to women's education and decreases in birth rate).

If you were doing science fantasy, this contradiction wouldn't bother me -- but you seem to be trying hard to keep your physics realistic. That doesn't fit well with such an unrealistic socio-economic picture.

* https://www.un.org/development/desa/...ects-2019.html

** https://www.un.org/en/desa/world-pop...2-billion-2100
**

[Fred Brackin]

Originally Posted by Anaraxes

I also don't understand how the PCs can afford to take time off to have any sort of adventures. There's not really anywhere "along the way" from Venus to Mars, other than an extremely fortuitous Earth-Luna position. )

With realistic Newtonian propulsion systems there are _never_ any convenient stops along the way. If you're stopping there it's at best an intermediate destination with full Delta-V cost. If you didn't intend to stop there you probably _can't_ no matter how bad the emergency is.

[Frost]

Originally Posted by Anaraxes

I also don't understand how the PCs can afford to take time off to have any sort of adventures. There's not really anywhere "along the way" from Venus to Mars, other than an extremely fortuitous Earth-Luna position.

Playing about with the assumptions a bit (and thinking as I type) for a suitably automated ship the ship being in transit from Venus to Mars =/= crew are in transit from Venus to Mars.

If your cargo ships are remotely operated then your crew can be somewhere where they are perfectly capable of getting caught up in various adventures (government/ corporate shenanigans, illegal gambling ect).

I don't personally think that this is particularly implausible, you won't need a crew on board full time when you are hauling bulk cargo. But human oversight is still useful particularly if something goes wrong so having a remote crew (essentially a striped down mission control) makes sense even if the ship can perform routine operations automatically.

This option might be a step too far for the OP, but I thought it would be worth bringing up.

[scc]

Originally Posted by Varyon

I had considered this possibility, but that doesn't really work for a race. Either you need the beam spread out enough that you are wasting a lot of the energy (due to empty space the beam goes through; if that 10 TJ particle accelerator can safely manage up to 5 ships, each of those ships could probably manage on their own with a dedicated 1 TJ particle accelerator... and five 1 TJ devices would cost around half what one 10 TJ device would), or you need it narrow enough that all the ships would have to cooperate with each other (which is basically the opposite of a race) to avoid collisions (as otherwise the vessels in the back will block those in the front, causing the former to accelerate more rapidly).

But maybe I'm coming at this from the wrong direction. Are you going for realism here, or are you wanting more cinematic pay-no-attention-to-the-math-behind-the-curtains play?

So 10TJ is enough for a ship of this size to pull 2Gs, which is 2,000 times the accel a Mag Sail can normally pull, so you might be right, but I'm definitely aiming for the semi-realistic part of the spectrum.

Originally Posted by Anaraxes

I also don't understand how the PCs can afford to take time off to have any sort of adventures. There's not really anywhere "along the way" from Venus to Mars, other than an extremely fortuitous Earth-Luna position. (There's probably some wacky flyby scenarios that might involve Mercury or Jupiter or whatever, but I'm not competent to calculate those. But even if there were such, it'd just serve as a Great Filter for the racers; everyone who thinks of it winds up in the winning pack -- see the Cold Equations problem -- while everyone else automatically loses.) If the timing of the race is at all close, then you can't stop for a side quest, or you just lose the main one. The game would have to be cinematic enough that your hotshot pilot or brilliant engineer is somehow going to speed the ship up or make the route shorter to make up the time, unrealistic as that is.

Well the race itself is something of an adventure, but beyond that it's about what happens in port.

Originally Posted by Anaraxes

To me, a race sounds more like one event in a campaign than the basis of the whole campaign. The suspense of the race would seem to have to come mostly from skulduggery on the part of the competitors, perhaps politics and bureaucracy in getting a nitrogen contract in the first place (nods at Traveller's "Exit Visa" adventure). Once the ships launch, about all you've got to work with is the discovery of sabotage or stowaways. (And of course the nitrogen pirates, no doubt would-be competitors that didn't make it through the bureaucracy stage.)

You're right about it just being one event, but it's a reoccurring one. And the nitrogen contracts are very easy to get and having one is how you buy the ship, it's proof that you can pay the interest on the loan (It's a very long setup to make a lot of money)

Originally Posted by SydneyFreedberg

Wait. This civilization has enough ecological knowhow and energy to terraform multiple planets, but they can't prevent a food crisis on Earth, the one planet naturally habitable by humans and their food crops? For that matter, they can't control overpopulation in 2250, when UN demographers predict global population to peak around 2100* and fertility rates are already dropping, even in Africa, which has had the most births-per-woman on the planet**?

I understand the terraforming projects aren't far enough along to provide food or living space for people. But surely some of the underlying technology could be deployed to great effect on Earth -- to geoengineer away the impacts of global warming and other environmental mismanagement, for instance, or just to boost food production to keep up with population growth, or even to increase education & general welfare so people stop having so many babies (there's a particularly strong correlation between improvements to women's education and decreases in birth rate).

If you were doing science fantasy, this contradiction wouldn't bother me -- but you seem to be trying hard to keep your physics realistic. That doesn't fit well with such an unrealistic socio-economic picture.

* https://www.un.org/development/desa/...ects-2019.html

** https://www.un.org/en/desa/world-pop...2-billion-2100
**

So the terreformers are the EU, CANZUK, Japan, Israel, some former US states, and likely some other countries. The ones the famine, which is caused by ecological collapse from pollution are the sub-Saharan nations, other former US states, and maybe Brazil and India.

[SydneyFreedberg]

Originally Posted by scc

So the terreformers are the EU, CANZUK, Japan, Israel, some former US states, and likely some other countries. The ones the famine, which is caused by ecological collapse from pollution are the sub-Saharan nations, other former US states, and maybe Brazil and India.

Ok, I can believe human selfishness and short-sightedness are strong enough to keep different countries from helping each other. I’m still very skeptical that some countries would have the tech to do terraforming and other countries wouldn’t be able to deal with purely terrestrial ecological problems — in real life, technology spreads worldwide.

[DangerousThing]

Originally Posted by scc

You're right about it just being one event, but it's a reoccurring one. And the nitrogen contracts are very easy to get and having one is how you buy the ship, it's proof that you can pay the interest on the loan (It's a very long setup to make a lot of money)

With millions or billions of trips privately owned ships, there isn't enough money to pay a decent wage to each ship. A mass-driver is the only affordable solution.

[scc]

Originally Posted by SydneyFreedberg

Ok, I can believe human selfishness and short-sightedness are strong enough to keep different countries from helping each other. I’m still very skeptical that some countries would have the tech to do terraforming and other countries wouldn’t be able to deal with purely terrestrial ecological problems — in real life, technology spreads worldwide.

Actually I'm using people still being upset over the whole colonization of Africa thing causing problem when more advanced nations try to prevent practices like dumping toxic waste into rivers

Originally Posted by DangerousThing

With millions or billions of trips privately owned ships, there isn't enough money to pay a decent wage to each ship. A mass-driver is the only affordable solution.

So here's the thing, transfer orbits are like a two week window once a year, or at least that's what I'm assuming. If I use 1,000 ton tanks and fire them once a second during the window that's 1.2 billion or 1.2e9 tons a year and I need 2.4e15 tons transferred, at that rate it would take 2 million years to complete! Even if I assume the mass driver can fire year round, it's 86.4e6 tons a day or 31.5e9 tons a year.

Basically this is the thing where if you want it to happen you probably should look too closely at the economics.

[sir_pudding]

I find the combination of worrying about low-dv transfer orbits with large scale planetary engineering to be incongruous. If the former is a concern you really probably don't have the technology or the resources to do the latter. If you can confidently spin up 5x10^24 kg of Venus by 500 m/s, then you should be able to give a infintesimal fraction of that mass a similar delta-v.

[Fred Brackin]

Originally Posted by scc

A
So here's the thing, transfer orbits s.

You don't uee transfer orbits for mass driver payloads. You're not using limited reaction mass and you have no manned crews whose time in space you're trying to limit. You fire off payloads continuously and they get where they're going when they get there.

Even if you are using mag sails they're not well suited for transfer orbits. Mag sails don't have limited Delta-V to be conserved by using a Hohman orbit. They make thrust (in small amounts) on a continuoius basis without any energy expenditure after you deploy the sail.

This is most of why I originally thought you were using rocket ships. Rocket ships need Hohman orbits.

[Anthony]

Originally Posted by Fred Brackin

You don't uee transfer orbits for mass driver payloads.

You might. It depends how much velocity you want to build your mass driver for. I suspect it's easiest to have a modest size window.