The SubLight quests are given by Lilya Hagen on the Groundbreaker. You can find her by staying left after the Spacer's Choice gift shop. Look for the big SubLight Logo.
You can't start these quests until you either buy the Navkey from Gladys and go to Stellar Bay on Monarch, or make your way there yourself without it. Either way, you have to set foot in Stellar Bay or Lilya won't work with you.
There are 3 quests:
I made a choice at the end of the quests that SubLight wasn't happy with, but I got the achievement regardless.