Mipmapping on Tablets

Hello all.

I'm currently making a space sim for android tablets but am having a problem with what I believe is mipmapping. I have large textured billboards and 3D text meshes to indicate a nearby stars location when it is too far away to see. The distances are vast but it works fine on PC as you can see below:

However, on the android tablet we get some strange effects. The textured billboard and 3d text mesh have just become simple blocks. Very near stuff seems to render just fine, but as I zoom out they become increasingly blurred like below:

I think this is some problem with mipmapping but I've already disabled the option for the icons (I couldn't find one for the 3D text mesh). Any ideas on how to fix this for android devices?

I'm using a galaxy 2 S10.1 tablet for testing but there should be little difference between devices right?