Archive of Our Own

Chapter Text

Interestingly enough, the cost calculations for jumpships did not factor in jump range at all, so I fudged a bit and reduced the cost of the KF core. The other advantages for a smaller jump range were already discussed - less germanium required, larger cargo capacity due to smaller KF drive.

There’s no canon figure for how much germanium is required for a KF core, but I postulate it to be 0.5%, based on a number of factors to make the FASAnomics fit. For example, the Scout jumpship has a KF core of 85500 tons. 0.5% of that is already 427.5 tons. Earth’s IRL current annual germanium production is only 240 tons, much of it byproducts from coal ash and other ore residues, since germanium does not really exist as an ore on its own.

There is quite a bit of it in the crust, but it is all evenly spread out, so to get a quantity of germanium requires processing a lot of other stuff. If not extracted from coal ash and zine residues, then germanium can be extracted from sphalerite ores with only 0.3% germanium by mass. That 0.3%? That’s already considered high concentration.

So 0.5% already seems a lot of germanium for just one KF core. Any higher percentage would strain credulity, especially when we consider the initial colonisation wave from Earth, which used a lot of jumpships and hence KF cores. Some of it can be accounted for by Belter mining from germanium-rich asteroids, but even then they won’t be especially rich, because the abundance and distribution of germanium even in the asteroids of the Solar System would not be too far different from Earth’s.

Example, the Aquilla class was one of the designs used in the big Exodus from Sol. Its KF core was 50000 tons. So if 0.5% of it is germanium, then that means 250 tons of germanium was required for every Aquilla. Just ten of these ships, or similar sized FTL vessels, would mean 2500 tons of germanium would be required, which is already an incredible number and seems just plausible enough at a stretch.

Going back to the germanium economics calculations way back in Act II, I needed to rework it given the above estimate of 0.5% and the known cost of the KF drive. Since the Scout’s KF drive is 85,500 tons, and costs 217,950,000 C-bills, my earlier assumption of 25 million C-bills per ton of germanium just doesn’t work.

Instead, let’s say the germanium consists of 90% of the cost of the drive, but takes up only 0.5% of the mass. Then 427.5 tons of germanium costs 196,155,000 C-bills. Each ton costs about 460,000 C-bills, which seems more reasonable now, so that will be my personal figure going forward. In fact, the price of 460,000 C-Bills is almost double the IRL cost per ton of germanium in C-Bills (3062 C-Bills converted to 2021 USD).

That also means the stash Johann O’Reilly found on Alphard, worth 50 billion C-bills, was about 100,000 tons of germanium, enough to build the KF cores for about 200 Scout jumpships. Somewhat believable.

Somebody else said that having such a small amount of germanium in the KF core is a trivial mass, but I’ll just handwave it away as the secret sauce for the KF drive to work - a critical component, not the main component. Without this quantity of germanium, the process just would not work.

The ecosystem alluded to consists of several components - space/recharge station at the zenith/nadir jump point, starport in orbit around the colony. Jumpship jumps in, pushes cargo containers to station at the jump point. Dedicated space-only haulers run the station-to-starport route the usual way, accelerate, flip, then decelerate. They offload their cargo at the starport, then specialised ground-to-orbit ships would make the transit up and down the gravity well (too bad they don’t have space elevators). All these vessels should be cheaper, so to speak, because they do not need docking collars to negotiate with the KF field for FTL jumps. Strictly local assets.

The dropship on the collar would carry passengers, tourists, and more sensitive cargo, e.g. military equipment.

And there’ll be interesting implications of using a ‘primitive’ jump drive with a smaller maximum range. In science, we need a minimum of three data sets to establish any pattern or trendline. If only Winston had access to data from another jump drive that could jump further than 30 light years… 😛

Elcano Jumpship

Cost Breakdown