How many times can the augmented retro-thrusters be taken? ounce or multiple times

i assume once, though i could be wrong. most components can only be taken once far as i know

I think it says specifically when a component can only be taken once, so yes, you should be able to take it multiple times.

Thanks for the answers but I Really need a specific yes or no as my group wants to mount two of them on our Battle Cruiser. But I am wondering reinforced interior bulkheads have the same conundrum.

Anything with a cross by them on the Augments and Enhancements list can only be taken once. Thus Armour Plating, Armoured Prow and Tenebro-Maze can only be taken once. Augmented Retro-thrusters and Reinforced Interior Bulkheads do not have a cross, and thus they may be taken more than once.

The errata makes it clear that the Additional Facilities (e.g. Extended Supply Vaults, Murder-Servitors etc.) should also all have crosses, meaning each of them can only be selected once per vessel

Thanks Erathia that really helps.