Editing Purchasing (section)

=== Acquisition process ===
The revised [[Military acquisition|acquisition]] process for major systems in the [[United States Department of Defense|U.S. Department of Defense]] is shown in the next figure. The process is defined by a series of phases during which technology is defined and matured into viable concepts, which are subsequently developed and readied for production, after which the systems produced are supported in the field.<ref name="DAUP 01">[http://www.dau.mil/pubs/pdf/SEFGuide%2001-01.pdf ''Systems Engineering Fundamentals.''] {{webarchive|url=https://web.archive.org/web/20070927203501/http://www.dau.mil/pubs/pdf/SEFGuide%2001-01.pdf |date=2007-09-27 }} Defense Acquisition University Press, 2001</ref>

[[Image:Acquisition Process.jpg|center|thumb|560px|Model of the Acquisition Process<ref name = "DAUP 01"/>]]
The process allows for a given system to enter the process at any of the development phases. For example, a system using unproven technology would enter at the beginning stages of the process and
would proceed through a lengthy period of technology maturation, while a system based on mature
and proven technologies might enter directly into engineering development or, conceivably, even production. The process itself includes four phases of development:<ref name = "DAUP 01"/>

* Concept and Technology Development: is intended to explore alternative concepts based on assessments of operational needs, technology readiness, risk, and affordability.
* Concept and Technology Development phase begins with concept exploration. During this stage, concept studies are undertaken to define alternative concepts and to provide information about capability and risk that would permit an objective comparison of competing concepts.
* System Development and Demonstration phase. This phase could be entered directly as a result of a technological opportunity and urgent user need, as well as having come through concept and technology development.
* The last, and longest, phase is the Sustainment and Disposal phase of the program. During this phase all necessary activities are accomplished to maintain and sustain the system in the field in the most cost-effective manner possible.