This paper will review the performances of nickel/cadmium and nickel/hydrogen Geocentric Earth Orbital (GEO) satellite battery packs which have been evaluated at NAVSEA Crane for the Air Force and NASA-Glenn. The nickel/cadmium data will deal, in part, with the attempts to find space-qualified substitutes for the disappearance of Pellon 2505 as a separation material. The nickel/hydrogen data will illustrate the development of this chemistry as a substitute for nickel/cadmium batteries. (C) 2004 Elsevier B.V. All rights reserved.