Which phase is the longest in the Defense Acquisition System?

Which phase is the longest in the Defense Acquisition System?

• A. Materiel Solutions Analysis
• B. Technology Maturation and Risk Reduction (TMRR)
• C. Operations and Sustainment (O&S)
• D. Production and Deployment

Answer: (C)

Operations and Sustainment is the longest phase because, once a system is fielded, it requires ongoing readiness, maintenance, logistics, and upgrades for the entire operational life of the program. That lifecycle can span decades, with continuous spare parts supply, depot maintenance, software updates, training, and eventual disposal planning. In contrast, the earlier phases—analysis, risk reduction, and production—are finite in duration, focused on development and deployment. So sustainment stretches over the most calendar time and budget, making it the longest phase.

Operations and Sustainment is the longest phase because, once a system is fielded, it requires ongoing readiness, maintenance, logistics, and upgrades for the entire operational life of the program. That lifecycle can span decades, with continuous spare parts supply, depot maintenance, software updates, training, and eventual disposal planning. In contrast, the earlier phases—analysis, risk reduction, and production—are finite in duration, focused on development and deployment. So sustainment stretches over the most calendar time and budget, making it the longest phase.