The GOES satellite system, which has been operational since 1975, plays a critical role in weather forecasting. The continuous availability of GOES data is vital to the success of NWS’ approximately $4.5 billion systems modernization program. GOES is one of two weather satellite systems operated by NOAA; the other is a system of polar-orbiting satellites. Unlike the polar satellites, geostationary weather satellites are placed into a special orbit that allows them to continuously maintain the same view of the earth’s surface. Thus, they are uniquely positioned to observe the development of hazardous weather, such as hurricanes and severe thunderstorms, and track their movement and intensity so that major losses of property and life can be reduced or avoided. Further, the unique ability of geostationary satellites to provide broad, continuously updated coverage of atmospheric conditions over land as well as oceans is very important to NOAA’s weather forecasting operations. NOAA’s operating strategy calls for two GOES satellites to be active at all times—one satellite to observe the Atlantic Ocean and the eastern half of the U.S., and the other to observe the Pacific Ocean and the western part of the country. Figure 1.1 shows the coverage provided by two GOES satellites. GOES satellites have two primary instruments for collecting weather data: an imager and a sounder. The imager is akin to a camera; it collects data in the form of digital images of the earth or some part of it, based on radiation that is sensed at five different spectral wavelengths or “channels,” including four in the infrared range and one that corresponds to visible light. Forecasters use animated sequences of imager data to track the development of various weather phenomena. The sounder is mechanically similar to the imager but receives data much more slowly and is sensitive to a broader range of spectral wavelengths. The sounder’s sensitivity to 19 different channels allows it to collect data on a number of natural variables, such as temperature and humidity, and attribute those measurements to specific levels of the earth’s atmosphere. The data from both the imager and sounder are relayed to a ground station at Wallops Island, Virginia, which processes the data to make them usable by weather forecasters. Then the data are retransmitted back up to the GOES satellites, which broadcast them to the weather forecasting community. NOAA has never been directly responsible for the design and development of any of its meteorological satellites. Instead, the agency has relied on NASA’s expertise in spacecraft design and development. After NOAA defines user requirements for its satellite systems, it turns them over to NASA to contract with industry to design and develop satellites that meet NOAA’s needs. NASA launches and tests the satellites, which are subsequently turned over to NOAA to operate. Beginning in the 1970s, NASA had a formal ongoing program, called the Operational Satellite Improvement Program (OSIP), to develop and demonstrate experimental versions of advanced meteorological satellites and instruments. Successful designs from the OSIP program were often incorporated into NOAA’s operational satellite systems. OSIP was terminated in 1981 due to budgetary constraints at NASA. However, NASA continues to act as the procurement agent for NOAA’s weather satellites. Even though GOES satellites have been operational for over 20 years, only one major design change has been implemented. The first generation design was developed and operated experimentally by NASA in the 1960s and early 1970s and subsequently became the basis for the first operational satellites, GOES-1 through GOES-7. Figure 1.2 is an illustration of the first generation design. This series of satellites was “spin-stabilized,” meaning that the satellites slowly spun while in orbit to maintain a stable position with respect to the earth. While these satellites operated effectively, they had technical limitations that NOAA wished to eventually overcome. The imager and the sounder on these satellites shared the same telescopic viewing apparatus and could not collect data at the same time. Further, because the satellite was spinning, it had to collect data very slowly, capturing one narrow band of data each time that its field-of-view swung past the earth. A complete set of sounding data, for example, took 2 to 3 hours to collect. In 1982, the National Weather Service (NWS) within NOAA sponsored a review of what new technologies were available and what additional missions could be performed by a new generation of geostationary satellites. The review was supported by NOAA’s National Environmental Satellite, Data and Information Service (NESDIS) as well as by NASA’s Goddard Space Flight Center and industry representatives. Based on input from these sources, requirements for a new generation spacecraft were developed. The new spacecraft design, called GOES-Next, was a significant departure from the first generation GOES. For example, GOES-Next was to be “body-stabilized.” This meant that the satellite would hold a fixed position in orbit relative to the earth, allowing for continuous meteorological observations. Instead of maintaining stability by spinning, the satellite would preserve its fixed position by continuously making small adjustments in the rotation of internal momentum wheels or by firing small thrusters to compensate for drift. Further, the imager and sounder would be completely separate, so that they could function simultaneously and independently. These and other enhancements meant that the GOES-Next satellites would be able to collect significantly better quality data more quickly than the older series of satellites. However, the improvements would be made at the expense of a heavier and more complex spacecraft. Figure 1.3 is an illustration of the GOES-Next design. Although GOES-Next represented a complete redesign of NOAA’s geostationary satellite system, satellite industry observers told us that the technical risks involved in developing GOES-Next appeared in the early 1980s to be manageable. Polar-orbiting meteorological spacecraft had already evolved from spin-stabilized to body-stabilized designs, and the GOES-Next builder, Ford Aerospace, had already built a body-stabilized geostationary meteorological satellite for India. Furthermore, the instrument manufacturer, ITT Corporation, had proposed designs that were closely based on successful imagers and sounders it was building for NOAA’s polar-orbiting satellites. On this basis, NOAA did not authorize and NASA did not require engineering analysis prior to GOES-Next development work. Despite the spacecraft and instrument design heritage, the GOES-Next program experienced severe technical problems, massive cost overruns, and dangerous schedule delays. Technical issues that had seemed straightforward when the spacecraft design was being conceptualized proved to be substantially more difficult to implement. For example, the original design did not sufficiently take into consideration the harshness of geostationary orbit, which is subject to large daily temperature variations that can stress and warp ordinary materials. Accordingly, the scan mirrors on the instruments had to be completely redesigned using other materials. It was also discovered that it would be very difficult to establish the fine pointing necessary to meet requirements for accurately mapping the satellite’s detailed images to their exact position on earth. These and other problems led to an increase of over 200 percent in NOAA’s estimate of the overall development cost of the GOES-next program—from $640 million in 1986 to $2.0 billion in 1996. Also, the first launch of a GOES-next satellite, which had been planned for July 1989, did not occur until April 1994. This nearly 5-year schedule slip left NOAA in real danger of temporarily losing geostationary satellite data coverage. Fortunately, due to the exceptional robustness of the last remaining first-generation satellite, GOES-7, as well as the use of a borrowed European satellite, NOAA was able to avoid a gap in coverage. GAO reported in 1991 that design complexity, inadequate management of the program by NASA and NOAA, and poor contractor performance all contributed to the cost, schedule, and technical problems experienced by the GOES-next program. Although some technical problems remain, the first two of these satellites, GOES-8 and GOES-9, are now producing useful, high quality weather data daily. The GOES-Next contract with Space Systems/Loral is for five spacecraft, designated GOES-I through GOES-M. Once the first two in the series, GOES-I and GOES-J, were successfully launched and placed in orbit, they were redesignated GOES-8 and GOES-9 respectively. The other three spacecraft in the GOES-Next series, GOES-K, GOES-L, and GOES-M, are in various stages of production. The GOES-K spacecraft has been completed and is scheduled for launch in April 1997. If GOES-8 and GOES-9 are still operational then, GOES-K will be stored at a central location in orbit and activated when either of its two predecessors fails. GOES-M and GOES-L are planned to be launched in 2000 and 2002, respectively. GOES-M, which has a stronger frame than the other satellites in the series, will be launched ahead of GOES-L in order to accommodate a new and heavier secondary instrument for measuring the space environment, called the Solar X-ray Imager. In February 1996, the House Committee on Science, Subcommittee on Energy and Environment, requested that we review NOAA’s management of the GOES Program. On the basis of subsequent discussions with subcommittee staff, our specific objectives were to assess: (1) the agency’s strategy for procuring continuation series satellites, (2) what steps the agency should be taking now to prepare for the next generation series of satellites, and (3) whether the potential exists for improving the system and reducing costs in the long term.