The Global Positioning System (GPS) is now a global utility. The United States Air Force is the steward responsible for sustaining and modernizing the constellation. The current launch-to-sustain strategy implemented by the Air Force is not flexible, does not effectively support GPS modernization, and it does not lend itself to a future responsive launch paradigm. | A New Flexible Global Positioning System (gps) Constellation Sustainment Strategy by David B Goldstein, Paperback | Indigo Chapters