Today U.S. battery technology is clearly dominating the commercial communications satellite market. The recent development of common pressure vessel (CPV) NiH(subscript 2) batteries has even strengthened this position. However, the panel found that in other countries, notably Japan, clearly focussed development efforts are underway to bring more advanced battery systems (e.g., lithium ion batteries), from laboratory models through engineering development to prototype and flight experimental status. These efforts will lead over the next decade to batteries superior to comparable U.S. technology, provided that no comparable effort is undertaken in the United States. See site reports on Toshiba and NASDA in Volume II for more information on advanced battery developments in Japan.