Fuel cell power system development for LOX/LH/ 2 upper stage

The upper stage of all launch vehicles are currently powered by batteries. This works well for short duration operation on the order of a couple hours, however the battery gets very heavy if the upper stage is needed for a longer mission to deploy multiple satellites into a broad range of orbits or to provide de-orbit or parking orbit operations. For upper stage vehicles with LOX and LH2, an option under investigation is to use a fuel cell, mounted in place of the battery and powered by the propulsion reactants from launch pad to end of mission. Launch weight can be reduced substantially while still meeting all the operation requirements of the vehicle and the mission. Design and development activities are in progress to evaluate the Proton Exchange Membrane (PEM) fuel cell for a number of current and future upper stage vehicles.