Tested out 0.6.6. That power draw is much more reasonable, but my ship still needs that infinite energy for the remaining 20% or so extra power needed. There is also one brutal comparison to be made to vanilla here:
Compared with my vanilla vessel Chariot of similar capability, The Rook design has worse defense, roughly one-third the thrust, and costs over 400 additional platform tiles. Even after the reduced power draw, I still cannot make the defensive system reliably stop asteroids. At this point, I think the current mechanic needs either a way to directly damage asteroids or a much more fundamental redesign. My idea of escalating legal threats that actually damage asteroids might be worth considering.
If somehow you are getting better results than I am despite us using the same ship, then there is something strange at play here as my Fulgora runs on 0.6.5 were still worse than yours. I even found a new failure mode: asteroid hits, gets bounced upward, then crashes again. The central asteroid problem is somehow... worse?