Since the 1960s, the United States has operated two separate operational polar-orbiting meteorological satellite systems: the Polar-orbiting Operational Environmental Satellite (POES) series, which is managed by NOAA, and the Defense Meteorological Satellite Program (DMSP), which is managed by the Air Force. These satellites obtain environmental data that are processed to provide graphical weather images and specialized weather products. These satellite data are also the predominant input to numerical weather prediction models, which are a primary tool for forecasting weather 3 or more days in advance—including forecasting the path and intensity of hurricanes. The weather products and models are used to predict the potential impact of severe weather so that communities and emergency managers can help prevent and mitigate its effects. Polar satellites also provide data used to monitor environmental phenomena, such as ozone depletion and drought conditions, as well as data sets that are used by researchers for a variety of studies such as climate monitoring. Polar satellites gather a broad range of data that are transformed into a variety of products. Satellite sensors observe different bands of radiation wavelengths, called channels, which are used for remotely determining information about the earth’s atmosphere, land surface, oceans, and the space environment. When first received, satellite data are considered raw data. To make them usable, the processing centers format the data so that they are time-sequenced and include earth location and calibration information. After formatting, these data are called raw data records. The centers further process these raw data records into channel-specific data sets, called sensor data records and temperature data records. These data records are then used to derive weather and climate products called environmental data records (EDR). EDRs include a wide range of atmospheric products detailing cloud coverage, temperature, humidity, and ozone distribution; land surface products showing snow cover, vegetation, and land use; ocean products depicting sea surface temperatures, sea ice, and wave height; and characterizations of the space environment. Combinations of these data records (raw, sensor, temperature, and environmental data records) are also used to derive more sophisticated products, including outputs from numerical weather models and assessments of climate trends. Figure 2 is a simplified depiction of the various stages of satellite data processing, and figure 3 depicts examples of two different weather products. With the expectation that combining the POES and DMSP programs would reduce duplication and result in sizable cost savings, a May 1994 Presidential Decision Directive required NOAA and DOD to converge the two satellite programs into a single satellite program capable of satisfying both civilian and military requirements. The converged program, NPOESS, is considered critical to the United States’ ability to maintain the continuity of data required for weather forecasting and global climate monitoring. To manage this program, DOD, NOAA, and NASA formed the tri-agency Integrated Program Office. Within the program office, each agency has the lead on certain activities: NOAA has overall program management responsibility for the converged system and for satellite operations; the Air Force has the lead on the acquisition; and NASA has primary responsibility for facilitating the development and incorporation of new technologies into the converged system. NOAA and DOD share the cost of funding NPOESS, while NASA funds specific technology projects and studies. In addition, an Executive Committee—made up of the administrators of NOAA and NASA and the Under Secretary of Defense for Acquisition, Technology, and Logistics—is responsible for providing policy guidance, ensuring agency support and funding, and exercising oversight authority. Figure 4 depicts the organizations that make up the NPOESS program and lists their responsibilities. NPOESS is a major system acquisition that was originally estimated to cost about $6.5 billion over the 24-year life of the program from its inception in 1995 through 2018. The program is to provide satellite development, satellite launch and operation, and ground-based satellite data processing. These deliverables are grouped into four main categories: (1) the space segment, which includes the satellites and sensors; (2) the integrated data processing segment, which is the system for transforming raw data into EDRs and is to be located at the four processing centers; (3) the command, control, and communications segment, which includes the equipment and services needed to support satellite operations; and (4) the launch segment, which includes the launch vehicle services. When the NPOESS engineering, manufacturing, and development contract was awarded in August 2002, the cost estimate was adjusted to $7 billion. Acquisition plans called for the procurement and launch of six satellites over the life of the program, as well as the integration of 13 instruments— consisting of 10 environmental sensors and 3 subsystems. Together, the sensors were to receive and transmit data on atmospheric, cloud cover, environmental, climatic, oceanographic, and solar-geophysical observations. The subsystems were to support nonenvironmental search and rescue efforts, sensor survivability, and environmental data collection activities. The program office considered four of the sensors to be critical because they provide data for key weather products; these sensors are in bold in table 1, which describes each of the expected NPOESS instruments. In addition, a demonstration satellite, called the NPOESS Preparatory Project (NPP), was planned to be launched several years before the first NPOESS satellite in order to reduce the risk associated with launching new sensor technologies and to ensure continuity of climate data with NASA’s Earth Observing System satellites. NPP was to host three of the four critical NPOESS sensors, as well as one other sensor and to provide the program office and the processing centers an early opportunity to work with the sensors, ground control, and data processing systems. When the NPOESS development contract was awarded, the schedule for launching the satellites was driven by a requirement that the NPOESS satellites be available to back up the final POES and DMSP satellites should anything go wrong during the planned launches of these satellites. Early program milestones included (1) launching NPP by May 2006, (2) having the first NPOESS satellite available to back up the final POES satellite launch then planned for March 2008, and (3) having the second NPOESS satellite available to back up the final DMSP satellite launch then planned for October 2009. If the NPOESS satellites were not needed to back up the final predecessor satellites, their anticipated launch dates would have been April 2009 and June 2011, respectively. Over several years, we reported that NPOESS had experienced continued cost increases, schedule delays, and serious technical problems. By November 2005, we estimated that the cost of the program had grown from $7 billion to over $10 billion. In addition, the program was experiencing major technical problems with the VIIRS sensor and expected to delay the launch date of the first satellite by almost 2 years. These issues ultimately required difficult decisions to be made about the program’s direction and capabilities. The Nunn-McCurdy law requires DOD to take specific actions when a major defense acquisition program growth exceeds certain cost thresholds. Key provisions of the law require the Secretary of Defense to notify Congress when a major defense acquisition is expected to overrun its current baseline by 15 percent or more and to certify the program to Congress when it is expected to overrun its current baseline by 25 percent or more. In November 2005, NPOESS exceeded the 25 percent threshold, and DOD was required to certify the program. Certifying a program entails providing a determination that (1) the program is essential to national security, (2) there are no alternatives to the program that will provide equal or greater military capability at less cost, (3) the new estimates of the program’s cost are reasonable, and (4) the management structure for the program is adequate to manage and control costs. DOD established tri- agency teams—made up of DOD, NOAA, and NASA experts—to work on each of the four elements of the certification process. In June 2006, DOD (with the agreement of both of its partner agencies) certified a restructured NPOESS program, estimated to cost $12.5 billion through 2026—an increase of $4 billion more than the prior life cycle cost estimate. This restructuring decision delayed the launch of NPP and the first 2 satellites by roughly 3 to 5 years—a deviation from NOAA’s requirement to have NPOESS satellites available to back up the final POES and DMSP satellites should anything go wrong during those launches. The restructured program also reduced the number of satellites to be produced by relying on European satellites for the midmorning orbit and planning to use NPOESS satellites in the early morning and afternoon orbits. In addition, in order to reduce program complexity, the Nunn-McCurdy certification decision decreased the number of NPOESS sensors from 13 to 9 and reduced the functionality of 4 sensors. In addition, a new executive position—called the Program Executive Officer—was established to oversee the NPOESS program office and to report directly to the Executive Committee. The Program Executive Officer obtains weekly and monthly reports on the program’s cost, schedule, performance, and risks from the System Program Director, and in turn, provides monthly and quarterly updates to the Executive Committee. Table 2 summarizes the major program changes made by the Nunn-McCurdy certification decision, and figure 5 denotes the configuration of the planned polar-operational satellite program in the future. While the Nunn-McCurdy certification decision decreased the number of NPOESS sensors and reduced the functionality of others, it allowed for the reintegration of the canceled sensors if other parties choose to fund them. Table 3 describes the changes to NPOESS instruments. The changes in NPOESS sensors affected the number and quality of the resulting weather and environmental products, called EDRs.