Question why is it so easy today to build reusable rockets? Is it because the onboard cpu speed of the chips can solve more granular control problems with low latency?
replies(17):
* Better motors for gimballing
* Launch-thrust engines that throttle down low enough and preciesly enough for landing
* Better materials to handle stress for flip over manover etc without added weight
* More accurate position sensors
* Better understanding and simulation of aerodynamics to develop body shape and write control algorithms.
> Launch-thrust engines that throttle down low enough and preciesly enough for landing
In large part this is due to improved simulation- spaceX made their own software: https://www.youtube.com/watch?v=ozrvfRHvYHA&t=119s
Experimentation was also a large factor- pintle injectors have been around for a long time, but were not used in production rockets until SpaceX (who moved from a single pintle to an annular ring). Pintle injectors are very good for throttling.
> Better materials to handle stress for flip over manover etc without added weight
We're still using the same materials- good ol inconel and aluminum. However 3d printing has made a pretty big difference in engines.
More rockets use carbon fiber, but that isn't new exactly and the main parts are still the same variety of aluminum etc. Titanium has become more common, but is still pretty specialized- the increased availability was probably the biggest factor but improved cutting toolings (alloys and coatings) and tools (bigger, faster, less vibration) have also made a big difference.