Just recently I was reading about supermemo, a tool that’s about 30 years old but has been updated and focuses on improving retained memory. It was developed by Piotr Wozniak who based on this 2008 article has taken the system as far as humanly possible by surrending his life to the algorithm.
https://www.wired.com/2008/04/ff-wozniak/
The supermemo algorithm has been published and you’ll find all sorts of implementations including the Ruby gem forgetful.
I read the mnemonic memory article and I didn’t see what differs between orbit and supermemo, but that doesn’t mean the approaches are the same.