In a distant future where FTL interstellar travel is commonplace, there is a stable large-scale market for a commodity called photonic negentropy ("PhoNE" for short, though nobody remembers what the word was once used for). PhoNE is a kind of consumable "wonder-stuff" that facilitates the construction and operation of self-repairing nanomachinery. A constant supply of it makes a system more or less self-sufficient, in place of repairing or replacing components by hand, though it is used mostly in technology that can't reliably be accessed by repair drones or personnel properly. It occurs naturally in the vicinity of stellar outflows, with asymptotic giant branch stars being the best source (but all stars producing some). Some believe, perhaps religiously, that its existence is a mark of the entire universe preparing to recycle itself.
PhoNE is harvested with sails, large sheets of smart-matter fabric that sieve out the useful part of stellar wind, and stored in battery-like cells for trade. It is a reliable commodity everywhere in civilized space: it is always in demand, and just about every station and planet has people willing to buy and sell it, albeit at unfortunately low prices. System-wide governments or major corporations typically put huge banks of static sails in low solar orbits, collecting their batteries every so often, while ships can mount their own sails for lower quantities of it.
There is at least one way in which PhoNE is not really a commodity: it is still somewhat profitable to collect it yourself. In our world, if you try to start a one-man operation for some fungible resource like iron, then even ignoring the initial investment you have no hope of breaking even, because economies of scale have lowered the price such that only the largest industrial mining operations can profit.
But, for whatever reason I'm trying to figure out, that's not the case with PhoNE. While high-speed transports, warships, and such don't mount sails because the returns are tiny and they need to save space and weight, there is a small interstellar community of private yacht and passenger-ship owners who do. They collect PhoNE on their voyages, use some fraction to save on their own maintenance, and sell the rest when they dock, in order to pay for docking permissions and any reasonable purchases they have to make in station. It's not lucrative by any means — investing in stocks is probably better for returns overall if you're already rich — but it's enough to get by and support someone who wants to be a "self-sufficient" spacer. In fact, there are even debt-relief agencies who will rent out harvesting ships to spacers, take a cut of the PhoNE sales, and let their client use the rest to pay off debts.
I'm trying to figure out how this can be the case. Something about the nature or harvesting of this material means that, even with the bulk of intake being provided by giant industrial sail operations, it's possible to get by, though not get rich quick, off going out in a ship with a sail and harvesting it oneself. What is it?
As requested, a few details on the economics:
- A starship's warp drive runs off reactor power alone, and can push a vehicle in any direction from any location (though warp entry and exit points must be in vacuum). In-system travel is limited, by the rate of warp acceleration, to a few dozen times the speed of light, and is monitored in civilized systems by remote-control warp stations that can control nearby flights to prevent accidents. Travel between systems takes at least half a day; most civilian vehicles have a reliable top speed of about 10,000c (~0.4 pc/hr) but take several more hours to get up to speed or slow down. There is no limitation on how far a warp trip can take a ship.
- Mass recycling is quite robust even without any PhoNE-based tech, so a ship designed for long-haul flights can stay out in space comfortably for many years. Anti-aging treatments are cheap and commonplace, but living for decades or centuries as a spacer is considered fairly weird. So the main timer on when you have to come back to port is mostly societal (is there a port to come back to?)
- A minimally functional warp-capable starship is just about affordable for a middle-class person who wants to burn all their money on one, though renting is far cheaper — ships are built to last a long time. The equipment for storing and handling PhoNE is inexpensive compared to the somewhat more expensive ship you need simply to be big enough to carry it.
- I do not have a clear notion of how much harvesting one needs to do to pay for trip expenses. Consider this a free variable for an answer.