The OCO-2 Validation Matrix: A Systematic Approach to Mission Validation

The Orbiting Carbon Observatory (OCO-2) mission was launched on July 2nd 2014 on the first of the last set of Delta II rockets from Vandenberg Air force Base. It is currently operating in the A-train and collecting data that will help scientists to understand the global carbon cycle. As with all NASA missions the OCO-2 mission went through a rigorous V&V (Verification and Validation) program. The program used the DOORS (Dynamic Object Oriented Requirements System) tool to implement a verification matrix complete with detailed verification activities that were used to accept the associated requirements as verified. On the other side of V&V is validation, and there are several methods that can be taken to construct a validation plan, unfortunately, few provide the ease and simplicity of the verification matrix used on OCO-2. In addition it is almost impossible to know conclusively that your system is fully validated until it is operating in space. In order to better prioritize the validation program of the OCO-2 mission the OCO-2 project V&V team developed and utilized a “validation matrix”. This matrix was used to help focus the OCO-2 ORTs (Operational Readiness Tests) and other validation testing on specific objectives and to optimize other tests as needed. While not all of the objectives identified in the matrix were closed during the ORTs it did provide the V&V team a method by which they could feel confident that the operations team, processes and procedures and the spacecraft observatory were ready for launch & operations. In this paper we will discuss the process used for developing the OCO-2 validation matrix, and how it was used in practice during the OCO-2 testing program. INTRODUCTION Validation is often describe as a method for ensuring that the mission that was built/designed will meet the objectives of the people who originally conceived the mission. Unfortunately it is difficult to determine what constitutes a good validation test, and determine when enough validation testing has been completed in order to demonstrate that the mission has been fully validated. On OCO-2 we attempted to answer both of these questions with a validation matrix, crafted and used by the team to make sure the right validation tests were being performed and that they covered the full scope of the OCO-2 mission.