The latest update for the ZR2 app now re-introduces the Supply Missions from Season 1. These missions are not storyline related and do not end. They go on for as long as you want. When you end the mission, the final audio clip plays. I haven’t checked since the update, but as these are optional, I don’t believe they will give you Materials for your base. Also, in the original ZR app, you could only do supply missions after playing certain missions. For example, you could only play the Fuel Run Supply Mission after the mission where you are introduced to Ed and Molly. Such a restriction is no longer the case.