Complete all challenges for 7 weeks
Complete all the challenges for seven given weeks to unlock the seventh of the seven challenges. Once you've got your loading screen, head to quadrant G5 and head inside the research facility of Dusty Divot. The meteorite is now open and the final battle token is resting on top of the mysterious object that was found inside.
If you look at the loading screen you unlocked, you'll be able to see the battle token above object that was found inside the meteorite.