All of these mods are supported for 1.12.1. You can find the timeline here: https://www.alternatehistory.com/wiki/doku.php?id=timelines:eyes_turned_skyward_media
MechJeb2: https://www.curseforge.com/kerbal/ksp-mods/mechjeb Kopernicus: https://github.com/Kopernicus/Kopernicus/releases
Bluedog design bureau: The prevoius american programs (Mercury, Gemeni) before the timeline, the saturn/apollo aspects, the carrack rocket, and Skylab/Spacelab parts.
Tantares: the russian rockets/spacecraft. parts can be used to make the russian space stations/rockets from the history.
Knes: Possibly the europa rockets although i havent tried yet.
MK-33: adds the X-33 spacecraft from eyes turned skyward.
Habtech 2: adds most of the american space station parts
Stockalike station parts expansion redux: adds parts for the challenger module(Freedom) and the Discovery space station.
Making alternate history: adds the artemis lander/base parts.
ProbesPlus: adds many parts for the probes in the history.
Outer planets mod: adds the outer planets :)
Minor planets expansion: adds many of the asteriods/dwarf planets from the missions to them
CSA Contares 'NIP': adds parts for the HOPE shuttle and japanese rockets from the history.