Once the CATE effort was complete, an independent validation of the cost estimates was performed using the Complexity Based Risk Assessment (CoBRA) tool developed by Aerospace Corporation (schedule evaluations were also performed but are not presented). Figure C.6 shows the mapping of the three space mission candidates, JDEM-Omega, LISA, and IXO, on a plot representing the results of approximately 40 analogous successful missions (indicated by green triangles).
The results show excellent correlation with each other and with the existing mission data set, indicating that the contractor estimates compare favorably with the costs of other successful missions of similar complexity. As would be expected, the 70 percent point is above the average (designated by the green line), basically representing the 50 percent mean for the data set. Similarly the NASA estimates fall near or below the mean, which is consistent with the S-curve results discussed above. This plot supports the conclusion that the contractor costs are reasonable and represent a realistic 70 percent confidence estimate based on the information provided for the assessment.