A bipolar high-voltage network for an aircraft or spacecraft. The network includes at least one DC-DC converter having two unipolar input connections and two bipolar output connections as well as a reference potential connection, at least two fuel cell stacks which are coupled in series between the two unipolar input connections, and at least two discharge diodes, each connected in parallel with the output connections of one of the at least two fuel cell stacks. The DC-DC converter is operable selectively in a step-up converter mode of operation or a step-down converter mode of operation, as a function of an input voltage between the unipolar input connections.