Unless I'm completely wrong, placing the objective marker 30" from the left side of the board and 6" from the center means it starts inside of the defender's deployment zone. I feel like this mission is strongly imbalanced, and the lack of clarity as to withholding units based on unit count or point value, coupled with the ability for units that naturally have Ambush to deploy unrestricted by the mission rules (meaning that units such as the Burrower can simply pop up right on the left side of the board) makes me think that the defenders are facing a significantly losing proposition.
The mission lore doesn't make a lot of sense to me, either. This base is set up on a hostile planet...is it naturally hostile to both armies? Then there should be some sort of natural hazard. Is it located in hostile territory? If so, it's only hostile to one side. The defenders start with vital supplies inside their base, but there's no indication why 'vital supplies' would be stored in such a distant base in hostile territory.
Overall this is a fun idea that just doesn't quite feel correctly implemented.