Using a Lander Rocket and going after Asteroids is less than intuitive. Maybe the tutorial is good at explaining it, maybe not.
In either case, bugs and unexpected behavior of the rockets lessens the experience of harvesting asteroids.
Post your gotchas and gameplay below. Maybe someone has an experience I can fix.
I can control a lot in this mod, but some things I cannot.
Here is one of my gotchas ...

One gotcha that gets everyone is waiting for crew.
You selected your crew, the screen said I had the crew, why isnt the crew loading?
Well I noticed it too. An example: I asked for 9 non-specialists, rocket said I had them when I hit request.
The cargo took time to load, the rovers and drones go next, and then the crew.
In that time several of my non-specialists graduated MartianU. I didnt have enough non-specialists to fill the crew request.
The rocket will wait until I get some more or I change the crew request.
Same can happen if a colonist turns senior, or dies and you dont have enough when the rocket is ready to launch.
Hopefuly I gave you enough exposed information to figure this out.

Anothe gotcha ...
Never build a Micro G Mining Facility before the Micro G Habitat. There is a bug where if the mine is built before the habitat the mine never see's the habitat and never extracts a thing.