Readit NewsI think we would get all this technology without going to the moon or Space Shuttle program. GPS, for example, was developed for military applications initially.
A ship travelling at 0.01c for 400 years could get 4 ly away. They'd still be able to be coached. More likely: their computers would still be able to be updated.
Regarding the GDP needed once you have a working "mine from the moon and send to orbit" economy it doesn't seem to be too bad. The assumption would be that a lot of technology is already developed for other projects. Launching it all from earth obviously wouldn't be possible even with vastly cheaper launch. That's why they put the build into the moon-earth L1 lagrange point to be easily reachable from the moon.
For propulsion and reactors, but there are multiple projects today working on all of this. Building a life support system for 400 years is still an unsolved problem however.
Re: spin. I still claim that the best design is to rotate entire living module as one. Most of the activity is going to be on the outer shell. Warehouses, etc will be in the lower gravity inside. No moving parts.
The only question is what to do with fuel and retro engines. Rotate them as well? Fuel tanks need to be stronger. Do not rotate? Then maybe living module can undock for the flight and rotate separately.
These are supposed to be generational ships. Now imagine you need to take the primary drive down for maintenance? What does the moving colony have for power?
I'd want tri-redundant systems at a least, for everything.
Even without taking this into account all systems are going to need active guidance - there is no way you do single burn and end up in the same place in the same time few light years away.
The best schema is probably launching all fuels containers that should be picked up for retro burn at the same time with much higher acceleration (orbital rail gun and then a burner), and with very slightly smaller final speed.
Then on the main craft you do short retro burn to match speed to fuels containers, attach them and do full retro burn for orbital insertion.
Benefit of this schema is that you don't need to accelerate everything slowly using main engine, so your original booster can be way smaller. (Energy-wise it only works if you have stationary means to accelerate high-g-capable payloads, i.e. orbital railgun, in this case you don't have to accelerate extra fuel required for initial burn)
https://www.canva.com/design/DAGmr3ubC8E/LHHAeeAIGGQe_TkZVs-...
Power provided by toroidal nuclear fusion reactors in the outer shell of the living module, but why do you need such reactors if your primary propulsion is provided by Helium 3 - Deuterium Direct Fusion Drive? If you have direct fusion technology, you don't need toroidal reactors.
Rotating inner shells mechanically for 400 years is terrible design, it's much easier just to rotate entire structure. Once it's going it keeps rotating inertially!
Another comment points to error in speed calculation - at declared acceleration they should go at 0.1c, not 0.01c!
And what is missing of course is the calculation of how many years of current world's GDP is required to complete such project event if all yet-to-be invented technologies exist.
Looking at the artwork on my wall, there’s two big things that set prints apart from an original artwork. 1. Computer software doesn’t capture the imperfection of a physical medium. 2. Printers can’t reproduce the texture of layered colors.
I have Epson EcoTank, which is great since I can refill it from the ink bottles (even non-Epson), but since it gets only occasional use for color printing, almost every time I have to clean nozzles before printing in color.