Short answers, pulled from the story.
The year 1971 marked a turning point when the STRIPS planning system introduced action names ordered in a sequence for robot execution. This early framework defined the simplest possible planning problem known as Classical Planning Problem.
Michael L. Littman showed in 1998 that branching actions made planning problems EXPTIME-complete. These mathematical bounds defined the theoretical limits of what algorithms could achieve under varying conditions.
The Hubble Space Telescope utilized short-term systems called SPSS alongside long-term planning frameworks named Spike. Autonomous robots and unmanned vehicles executed strategies discovered through multidimensional space optimization processes.
Haslum and Jonsson demonstrated that conformant planning problems reached EXPSPACE-complete status when initial situations remained uncertain. Non-determinism in action outcomes pushed complexity further to 2EXPTIME-complete levels.