I don't think you would need to assemble anything in space. Starship's planned LEO payload is about a third of the entire mass of the Ariane 5 rocket that launc

I don't think you would need to assemble anything in space. Starship's planned LEO payload is about a third of the entire mass of the Ariane 5 rocket that launched Juice. If you have that kind of mass budget at orbit, your delta v capability is pretty massive for a space probe.