NASA's tough mission: Dismantling Constellation, Orlando Sentinel

"Many of the deals are called "undefinitized contracts," meaning that the terms, conditions -- and price -- had not been set before NASA ordered the work to start. That means the agency will need to negotiate a buyout with the contractor -- and that can be a long and painful process, according to government officials familiar with the cancellation process. "It can be messy, and it's going to take at least a year after the project is closed to get a final price tag assigned to many of these contracts," said one congressional investigator not authorized to talk publicly about his work."

NASA: Constellation Program Cost and Schedule Will Remain Uncertain Until a Sound Business Case Is Established , GAO, August 2009

"Undefinitized contract actions authorize contractors to begin work before reaching a final agreement on contract terms. By allowing undefinitized contract actions to continue for extended periods, NASA loses its ability to monitor contractor performance because the cost reports are not useful for evaluating the contractor's performance or for projecting the remaining cost of the work under contract. With a current, valid baseline, the reports would indicate when cost or schedule thresholds had been exceeded, and NASA could then require the contractor to explain the reasons for the variances and to identify and take appropriate corrective actions. Yet, NASA allowed high-value modifications to the Constellation contracts to remain undefinitized for extended periods, in one instance, more than 13 months."