75 tons was ridiculous and honestly we never should have released such a bulky monstrosity in the first place. The new Deliverator Slim is now a mere 73 tons!
Turns out the amount of water produced from melting ice is 20, and the amount of water needed for fuel and oxidizer is 10 each. So instead of cycling between fuel and oxidizer with a water override, we can just cycle to run one of each recipe. No storage tanks necessary!
R&D was also informed about a width issue with previous designs. With the removal of the water storage tank we were able to dramatically improve aerodynamics. For very brief periods of time while flying towards a planet, this sucker can hit 50km/s!
Width does affect how many asteroids you need to clear, so I suppose it is astrodynamic.