Milestone B is a Milestone Decision Authority (MDA) led review at the end of the Technology Maturation & Risk Reduction (TD) Phase in the Defense Acquisition Process. Its purpose is to make a recommendation or seek approval to enter the Engineering and Manufacturing Development (EMD) Phase. Milestone B is considered the official start of a program. A milestone marks the start/or finish of a phase and has defined Entrance and Exit Criteria.
Definition: Milestone B is the point at which a program is reviewed for entrance into the Engineering & Manufacturing Development (E&MD) Phase. 
Figure: Defense Acquisition Process
Main Milestone References
Milestone B Approval Requirements
For a list of mandatory items due at Milestone B, see the Milestone Requirements Matrix
A Major Defense Acquisition Program (MDAP) may not receive a Milestone B approval until the Milestone Decision Authority (MDA) certifies, without modification, from 10 USC 4252 of title 10, United States Code (USC) and as amended by Public Law 111-23, “Weapon Systems Acquisition Reform Act of 2009”, May 2009, that:
- The MDA has received a Business Case Analysis and certifies on the basis of the analysis that:
- the program is affordable when considering the ability of the Department of Defense (DoD) to accomplish the program’s mission using alternative systems;
- appropriate tradeoffs among cost, schedule, and performance objectives have been made to ensure that the program is affordable when considering the per-unit cost and total acquisition cost in the context of the total resources available during the period covered by the future-years defense program submitted during the fiscal year in which the certification is made;
- reasonable cost and schedule estimates have been developed to execute, with the concurrence of the Director of Cost Assessment and Program Evaluation (CAPE), the product development and production plan under the program;
- funding is available to execute the product development and production plan under the program, through the period covered by the future-years defense program submitted during the fiscal year in which the certification is made, consistent with the estimates described for the program; and
- The MDA has received the results of the Preliminary Design Review (PDR) and conducted a formal post-preliminary design review assessment, and certify on the basis of such assessment that the program demonstrates a high likelihood of accomplishing its intended mission; and
- The MDA certifies that:
- appropriate Market Research has been conducted prior to technology development to reduce duplication of existing technology and products:
- the DoD has completed an Analysis of Alternatives (AoA) with respect to the program;
- the Joint Requirements Oversight Council has accomplished its duties with respect to the program pursuant to section 181(b) of Title 10 United States Code, including an analysis of the Operational Requirements for the program;
- the technology in the program has been demonstrated in a relevant environment as determined by the Milestone Decision Authority (MDA) on the basis of an independent review and assessment by the director of Defense Research and Engineering; and the program complies with all relevant policies, regulations, and directives of the DoD.
Program Support Review
The Program Support Review (PSR) is conducted to provide insight into current and future program execution through detailed analysis using the Defense Acquisition Program Support (DAPS) Methodology. A PSR is designed to assist the Program Managers (PM) and systems engineer prepare for Milestone A, B, and C decision reviews.
A few programs are allowed to have a combined Milestone B and Milestone C. These programs do not produce prototypes during Engineering Manufacturing & Development (EMD) due to high costs such as satellites and ships. In that case, the first article produced will be tested and evaluated, and then fielded as an operational asset.
The acquisition approach for these programs can be tailored by measures such as combining development and initial production investment commitments and a combined Milestone B and C. Additional decision points with appropriate criteria may be established for subsequent production commitments.
AcqLinks and References:
-  Defense Acquisition Guidebook (DAG)
- DoD Directive 5000.01 “Defense Acquisition System”
- DoD Instruction 5000.02 “Operation of the Defense Acquisition System”
- Improve Milestone Process – 23 June 2011
- Website: 10 USC § 4251 “Major Defense Acquisition Programs”