Change the ship color

The rootKey that you are changing is, to the best of my knowledge, Starbound's root certificate, which identifies Starbound's certificate authority (CA). This is all fancy computer speak for knowing where your computer's photo ID comes from. Not being able to identify the CA results in a failed authentication, which makes the game crash.

There is no way to change the universe as a whole, but coordinates to planets are like Minecraft seeds. If you want to go to the same planet as someone, you can use their coordinates. Unfortunately due to the way planets generate, using coordinates only changes the planet's biome, and does not affect dungeon and/or ore spawns.

Source: Reddit and testing myself.

Stim Pack Status Effect

Red Stim Pack       Regeneration
Blue Stim Pack      Jump Boost
Green Stim Pack     Speed Boost
Yellow Stim Pack    Glow

Source: Here