So I play this mod a lot, in fact I never play Homeworld without it. I made a shortcut that helps me bypass the dumb launcher and wanted to share it here so anyone else who would prefer to quickstart into their mods can use.

First go into your Steam\steamapps\common\Homeworld\HomeworldRM\Bin\Release and make a shortcut of HomeworldRM.exe

Then open the properties for the shortcut and add this to the end of the Target line
-workshopmod 76561198021899706\759628723\STCR.big

The numbers there might be different on each machine but I think they're the same. If it doesn't work you might have to get the numbers yourself from your
Steam\steamapps\common\Homeworld\HomeworldRM\DataWorkshopMODs

Make sure steam is running first :)