Since the 1960s, the United States has operated polar-orbiting satellite systems that obtain environmental data to support weather observations and forecasts. These data are processed to provide graphical weather images and specialized weather products. Data from polar satellites are also the predominant input to numerical weather prediction models, which are a primary tool for forecasting weather days in advance—including forecasting the path and intensity of hurricanes. These 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-orbiting satellites circle the earth in a nearly north-south orbit, providing global observation of conditions that affect the weather and climate. Each satellite makes about 14 orbits a day. As the earth rotates beneath it, each polar-orbiting satellite views the entire earth’s surface twice a day. Currently, the polar-orbiting satellites that are considered primary satellites for providing input to weather forecasting models are a NOAA/NASA satellite (called Suomi National Polar-orbiting Partnership, or S-NPP), two Department of Defense (DOD) satellites, and a series of European satellites. These satellites cross the equator in early morning, mid-morning, and early afternoon orbits, with S-NPP in the early afternoon orbit. NOAA, the Air Force, and a European weather satellite organization also maintain older satellites that provide limited backup to these operational satellites. Figure 1 illustrates the current operational polar satellite constellation. According to NOAA, 80 percent of the data assimilated into its National Weather Service numerical weather prediction models that are used to produce weather forecasts 3 days and beyond are provided by polar- orbiting satellites. Specifically, a single afternoon polar satellite provides NOAA 45 percent of the global coverage it needs for its numerical weather models. NOAA obtains the rest of the polar satellite data it needs from other satellite programs, including DOD’s early morning satellites and the European mid-morning satellite. NOAA is currently executing a major satellite acquisition program to replace existing polar satellite systems that are nearing the end of their expected life spans. NOAA established the JPSS program in 2010 after a prior tri-agency program was disbanded due to technical and management challenges, cost growth, and schedule delays. The JPSS program guided the development and launch of the S-NPP satellite in 2011 and is responsible for two other planned JPSS satellites, known as JPSS-1 and JPSS-2. The current anticipated launch dates for these two satellites are March 2017 and December 2021, respectively. More recently, NOAA has also begun planning the Polar Follow-On (PFO) program, which is to include the development and launch of a third and fourth satellite in the series in July 2026 and July 2031, respectively. These are planned to be nearly identical to the JPSS-2 satellite. NOAA has organized the JPSS program into flight and ground projects that have separate areas of responsibility. The flight project includes a set of five instruments, the spacecraft, and launch services. The ground project consists of ground-based systems that handle satellite communications and data processing. The ground system’s versions are numbered; the version that is currently in use is called Block 1.2, and the new version that is under development is called Block 2.0. Among other things, Block 2.0 is to enable the JPSS ground system to support both the S-NPP and all planned JPSS satellites. Since 2012, we have issued reports on the JPSS program that highlighted technical issues, component cost growth, management challenges, and key risks. In these reports, we made 15 recommendations to NOAA to improve the management of the JPSS program. These recommendations included addressing key risks, establishing a comprehensive contingency plan consistent with best practices, and addressing weaknesses in information security practices. As we reported in May 2016, the agency had implemented 2 recommendations and was working to address the remainder. In particular, NOAA established contingency plans to mitigate the possibility of a polar satellite data gap and began tracking completion dates for its gap mitigation activities. NOAA has also taken steps such as performing a new schedule risk analysis, and adding information on the impact of space debris to its annual assessment of satellite availability. We have ongoing work reviewing the agency’s progress in implementing these open recommendations. Over the past year, the JPSS program has made progress in developing the JPSS-1 satellite, but continues to face challenges as it approaches the early 2017 launch date. The program completed all instruments on the JPSS-1 satellite and integrated them on the spacecraft by early 2016. As of December 2015, the JPSS program reported that it remained on track to meet its committed launch date of March 2017. However, as highlighted in our May 2016 report, the JPSS program continues to face challenges as it approaches the early 2017 launch date. Specifically, the JPSS program had experienced delays ranging from 3 to 10 months on key components since mid-2014, as well as technical challenges on both the flight and ground systems. For example, the program recently experienced multiple issues in completing a component on the spacecraft, called a gimbal, which moved the component’s planned completion date forward by almost a year before it was completed in March 2016. These issues in turn delayed the beginning of the JPSS-1 satellite’s environmental testing. The gimbal issue also was a factor in the program choosing to move back its launch readiness date—the date that the JPSS-1 satellite is planned to be ready for launch—from December 2016 to January 2017. Regarding the JPSS ground system, the program experienced an unexpectedly high number of program trouble reports in completing the upgrade to Block 2.0, which is needed for security and requirements improvements in tandem with the JPSS-1 satellite’s launch. A key milestone related to this upgrade was recently delayed from January to August 2016. While NOAA satellite timelines show continuous coverage in the afternoon orbit, the JPSS program still faces the potential for a near-term gap in satellite coverage. As we reported in May 2016, NOAA had increased the estimated useful life for S-NPP by up to 4 years. Under this new scenario, a near-term gap in satellite data would not be expected because S-NPP would last longer than the expected start of operations for JPSS-1. However, subsequent NOAA documentation showed this 4-year period as “fuel limited life.” NOAA officials explained that this extended period is based on expected fuel availability, and does not take into account the likelihood that the instruments and spacecraft will fail before the satellite runs out of fuel. In other words, the extended useful life depicts the satellite’s maximum possible life, not its expected life. As a result, the JPSS program continues to face a potential gap of 8 months between the end of S-NPP’s expected life in October 2016, and when the JPSS-1 satellite is launched and completes post-launch testing in June 2017. Figure 2 shows the potential gap period. The June 2017 completion date also assumes a 3 month period for the JPSS-1 satellite’s on-orbit checkout. However, based on on-orbit checkout periods from past polar satellites, it is likely that checkout could take longer than this, potentially lengthening the gap. As a precedent, it took the JPSS program about 2 years to fully validate the highest-priority data products from the S-NPP satellite. If S-NPP unexpectedly fails sooner, or the JPSS-1 launch date is delayed, a longer gap could result. In addition to its work in completing the JPSS-1 satellite, NOAA has begun planning for new satellites to ensure the future continuity of polar satellite data. In a new program, called the Polar Follow-On (PFO), NOAA plans to build two new satellites, JPSS-3 and JPSS-4, that are copies of the JPSS-2 satellite. Like JPSS-2, these satellites are to include all three key performance parameter instruments, as well as a fourth environmental sensor. NOAA plans to complete development of JPSS-3 and JPSS-4 several years ahead of their planned launch date. In the nearer term, NOAA plans to build a smaller satellite that can provide a replacement for some data produced by one of the most essential JPSS instruments. NOAA’s decisions on what PFO will include are based on what the agency calls a robust constellation, creating a situation where it would take two failures to create a gap on data from key instruments, and where the agency would be able to restore full coverage in a year in the event of a failure. We reported in May 2016 that NOAA has taken several steps in planning the PFO program, including establishing goal launch dates and high-level budget estimates. However, it had not completed formulation documents such as high-level requirements, a project plan, or budget information for key components. In addition, uncertainties remain about whether early development of JPSS-3 and JPSS-4 is necessary to achieve robustness. For instance, in its initial calendar for PFO, NOAA considered lifetimes of 10 years or more for the JPSS-1 and JPSS-2 satellites, while NOAA charts used for budget justification continue to show only 7 year lifetimes. If satellites are likely to last longer than expected, there could be unnecessary redundancy in coverage. Until NOAA ensures that its plans for future polar satellite development are based on the full range of estimated lives of potential satellites, the agency may not be making the most efficient use of the nation’s sizable investment in the polar satellite program. As a result of this uncertainty, we recommended that NOAA evaluate the costs and benefits of different launch scenarios for the JPSS PFO program, based on updated satellite life expectancies, to ensure satellite continuity while minimizing program costs.