Another attack option would be to...
Release neurotoxins/viruses!
Base suppliers can help combat it by getting more water (clean water, some water gets 'infected' by toxins, or some food.)
Buy pharmacutacles/medicine whatever (I can't spell) to cure Space Crew?
Infected ones are converted to the cargo type 'Infected space Crew' and can't be deleted or something? OR make it so it says 6 out of 100 of your crew have been diagnosed with Type 3 diseases! (and still stay the same cargo) - Or install medical bays on your station to help prevent further diseases?
If you're going to completely cure it, it will be tricky, deleting all water, space crew will leave your base open to attack.
Problem is, attackers! These special viruses are only developed on player bases with some sort of science or medical addon and cost a lot, or not? Something different from shooting. Gives medical things a use. And cryer, etc, can get jobs.
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Also another thing, add a shield meter (which is calculated by amount of fuel to determin the 'shield health') to bases? (like how you select ships and see a blue bar)