Definitely runnable without it.
I’ve only played Mothership for a oneshot (over multiple sessions) while waiting on a party member to become available.
We did not have TT/VTT. We had some visual aids, like the layouts of ships were sent in chat for us to look at. I don’t think it really hampered the experience, and I have aphantasia so “theater of the mind” usually doesn’t help me much lol. It was more than serviceable.















You’re welcome! My group enjoyed it for sure, I will say the companion app is a huge helper. We particularly liked how the rules aren’t overly complex and easy to homebrew.