Since the former Soviet Union launched its first Sputnik satellite 40 years ago, the number of manmade space objects orbiting the earth--active and inactive satellites and debris generated from launch vehicle and satellite breakups--has increased dramatically. In 1995, a National Science and Technology Council report estimated the number of space objects to be over 35 million. Although nearly all of these objects are thought to be smaller than 1 centimeter, about 110,000 are estimated to be between 1 and 10 centimeters, and about 8,000 are larger than 10 centimeters. Only the approximate 8,000 objects are large enough, or reflect radar energy or light well enough, to be routinely observed by the Department of Defense's (DOD) existing space surveillance sensors. About 80 percent of these 8,000 objects are in low-earth orbits, and the remainder are in geosynchronous and other orbits. The increasing amount of space debris creates a hazard to certain spacecraft, especially large ones like the planned multibillion dollar International Space Station, which will operate in low-earth orbits. The National Aeronautics and Space Administration (NASA) is interested in accurate and timely information on the locations and orbits of space objects to predict and prevent collisions with spacecraft designed for human space flight--the space station and space shuttles. DOD and intelligence agencies are interested in knowing the type, status, and location of space objects, particularly foreign satellites, as part of DOD's space control mission and other national security functions. NASA and DOD rely on the U.S. Space Command's Space Surveillance Network, which is operated and maintained by the Air Force, Naval, and Army Space Commands, to provide information on space objects. The surveillance network consists of radar and optical sensors, data processing capabilities, and supporting communication systems. It detects objects in space; tracks them to determine their orbits; and characterizes them to determine their size, shape, motion, and type. The network routinely detects and tracks objects larger than about 30 centimeters (somewhat larger than a basketball). It can sometimes detect and track objects as small as 10 centimeters (about the size of a softball), but not routinely. The surveillance network also catalogs the approximately 8,000 space objects and includes information that describes the orbit, size, and type of object. The information is used for such purposes as (1) warning U.S. forces of foreign reconnaissance satellites passing overhead and (2) analyzing the space debris environment and the potential implications of planned space operations. All space sectors--defense, intelligence, civil, and commercial--use the catalog information. Subsequent to the launch of Sputnik in 1957, DOD established a space tracking mission and a network of radars and telescopes to monitor orbiting satellites. During the 1960s, DOD built radars to support two missions--space tracking and ballistic missile warning. The Naval Space Surveillance System (known as the Fence) is a chain of radar equipment extending from California to Georgia that was constructed to detect foreign reconnaissance satellites and provide warning to Navy ships of such satellite overflights. The system is still operational, and the Navy plans to modernize it beginning in 2003 to improve its maintainability. Also, Ballistic Missile Early Warning System radars were constructed in Alaska, Greenland, and England to detect and track intercontinental ballistic missiles that could be launched at North America. A secondary mission for these missile warning radars has always been space surveillance. Finally, a prototype phased-array radar was built in Florida to support the space surveillance mission. During the 1970s, the Air Force reactivated the Safeguard antiballistic missile phased-array radar in North Dakota. This radar provides space surveillance support as a secondary mission. Also, the Air Force began a program to build four phased-array radars (called PAVE PAWS) to detect and track submarine-launched and intercontinental ballistic missiles. The four radars--in Georgia, Texas, California, and Massachusetts--were completed in the 1980s, but the Georgia and Texas radar sites were closed in 1995. The radars in California and Massachusetts continue to operate and support space surveillance as a secondary mission. During the 1980s, DOD acquired four Ground-based Electro-Optical Deep Space Surveillance telescopes to detect and track objects in geosynchronous orbit because existing surveillance network sensors could not detect objects at such a distance. These telescopes provide nearly worldwide coverage but are limited to operating at night and in clear weather. Three sites, located in New Mexico, Hawaii, and Diego Garcia (in the Indian Ocean), are currently operational. A fourth site in Korea was closed in 1993 due to poor tracking conditions. The existing space surveillance network includes 31 radar and optical sensors at 16 worldwide locations, a communications network, and primary and alternate operations centers for data processing. Appendix I discusses the surveillance network's composition and characteristics. The September 1996 National Space Policy includes civil, defense, and intersector guidelines related to space safety, space threats, and space debris. Specifically, the policy (1) requires NASA to ensure the safety of all space flight missions involving the space station and space shuttles; (2) requires DOD to maintain and modernize space surveillance and associated functions to effectively detect, track, categorize, monitor, and characterize threats to U.S. and friendly space systems and contribute to the protection of U.S. military activities; and (3) declares that the United States will seek to minimize the creation of space debris and will take a leadership role internationally, aimed at debris minimization. A distinctive interconnection among these policy guidelines is that, although the increasing amount of space debris creates a hazard to human space flight, NASA has no surveillance capabilities to locate space objects. Instead, it relies on DOD's capabilities to perform this function. Despite this dependency relationship, the policy makes no provision for an interagency mechanism--either organizational or funding--to ensure that DOD's space surveillance capabilities meet NASA's requirements. The surveillance of space objects is receiving increasing attention from both a civil and national security perspective. Part of the reason for the increased attention is because of (1) the planned assembly of the space station beginning in 1998 and (2) DOD's recognition that its aging space surveillance network cannot adequately deal with future national security threats. In addition, DOD believes that the growing commercial space sector will result in increased requests for surveillance support. According to the National Research Council, the chance of debris colliding with a spacecraft relates directly to the size and orbital lifetime of the spacecraft. The space station will be the largest spacecraft ever built, with length and width dimensions somewhat larger than a football field. Its total exposed surface area will be almost 10 times greater than that of a space shuttle--about 11,500 square meters compared with about 1,200 square meters. Also, the space station's orbital lifetime is expected to exceed that of a space shuttle. NASA plans to operate the space station continuously for at least 10 years. In contrast, in recent years, individual space shuttle missions have averaged about 7 per year and 11 days per mission. In future years, NASA is planning about eight shuttle missions per year. The Council concludes that the space station will face a significant risk of being struck by potentially damaging meteoroids or orbital debris. The space station is to operate at low-earth altitudes--between 330 to 500 kilometers. According to the National Science and Technology Council, debris orbiting at altitudes up to about 900 kilometers lose energy over time through friction with the atmosphere and fall to lower altitudes, eventually either disintegrating in the atmosphere or falling to the earth. New debris is periodically added, sometimes unexpectedly. For example, in June 1996, a Pegasus rocket broke up at an altitude of about 625 kilometers, creating 668 observable objects. Also, it is likely that an unknown number of other objects were created, but they are not observable because of their small size. Such debris, as it falls toward the earth, can be expected to pass through the space station's operating altitudes. From a national security (defense and intelligence) perspective, space surveillance provides (1) warning to U.S. forces when a foreign satellite becomes a threat to military operations and (2) information to support responsive measures. According to DOD, as the importance of space services to U.S. forces increases and the size of satellites decreases, the need for timely information about space objects expands. DOD has acknowledged that its existing surveillance network is aging, requires replacement or upgrades in the next 10 to 15 years, and is currently limited in its ability to detect and track objects smaller than 30 centimeters. In January 1996, the Deputy Under Secretary of Defense for Space directed the DOD Space Architect to begin a study of DOD's space control mission, including the space surveillance function. The purpose was to develop a range of architecture alternatives to satisfy national security needs to 2010 and beyond. In May 1997, the team provided its results to the Joint Space Management Board. Regarding space surveillance, the team concluded that next-generation ground-based radars and potential space-based systems should be able to provide reliable near-earth tracking of space objects that are 5 to 10 centimeters in size. The team expected such capabilities to improve debris awareness and ensure that an emerging class of microsatellites as small as 10 centimeters could be tracked. The Board has yet to provide directions to DOD and intelligence organizations on how to proceed regarding the space surveillance function. In a separate action, NASA and the Air Force Space Command established a partnership council in February 1997 to study a variety of space areas of mutual interest. One area involves DOD's space surveillance network. The impetus to address this subject arose from recognizing the potentially catastrophic consequences of collisions between manned spacecraft and orbiting debris. One of the tasks is to examine ways to enhance orbital debris data collection and processing on objects as small as 5 centimeters. The Chairman and Ranking Minority Member of the Subcommittee on Space and Aeronautics, House Committee on Science, expressed an interest in how NASA intends to ensure protection of the space station against space debris for which shielding will not be provided. As a result, they asked us to provide this report on NASA's and DOD's requirements and capabilities for detecting and tracking space objects and the existing relationships between the two agencies for carrying out their responsibilities in this area. We evaluated (1) how well DOD's existing space surveillance capabilities support DOD's and NASA's current and future surveillance requirements and (2) the extent to which potential space surveillance capabilities and technologies are coordinated to provide opportunities for improvements. To accomplish these objectives, we reviewed surveillance network studies; DOD's and NASA's surveillance requirements documents and emerging needs; reports, plans, and budgets associated with surveillance network operations, maintenance, and enhancements; and program documentation on potential capabilities. We also reviewed national space policy and interviewed DOD and NASA representatives responsible for space surveillance. We performed this work primarily at the U.S. and Air Force Space Commands, Colorado Springs, Colorado, and NASA's Johnson Space Center, Houston, Texas. In addition, we held discussions with and obtained documentation from representatives of the Office of the Deputy Under Secretary of Defense for Space; the Joint Staff; the Ballistic Missile Defense Organization; the Office of the DOD Space Architect; the Departments of the Air Force, the Navy, and the Army; the Naval Research Laboratory; and NASA Headquarters; all in Washington, D.C. We also acquired information from the Naval Space Command, Dahlgren, Virginia; the Air Force Space and Missile Systems Center, El Segundo, California; the Air Force Electronic Systems Center, Hanscom Air Force Base, Massachusetts; the Air Force's Phillips Laboratory, Albuquerque, New Mexico; the Army Space and Strategic Defense Command, Huntsville, Alabama; the National Oceanic and Atmospheric Administration's Office of Satellite Operations, Suitland, Maryland; the Massachusetts Institute of Technology's Lincoln Laboratory, Lexington, Massachusetts; and the University of Colorado's Aerospace Engineering Sciences, Boulder, Colorado. We visited the Air Force's Ground-based Electro-Optical Deep Space Sensor, Socorro, New Mexico; the Massachusetts Institute of Technology's Lincoln Space Surveillance Complex, Tyngsboro, Massachusetts; and NASA's Liquid Mirror Telescope, Cloudcroft, New Mexico. We obtained written comments from DOD and NASA on a draft of this report. These comments are reprinted in their entirety in appendixes II and III, respectively. Both DOD and NASA also provided technical and editorial comments, which we have incorporated into the report where appropriate. We performed our work from September 1996 to August 1997 in accordance with generally accepted government auditing standards. NASA has established some stringent space surveillance requirements to protect the space station and other spacecraft from collisions with space debris. DOD's space surveillance requirements are under review and are likely to become more stringent. Because DOD's existing space surveillance network cannot satisfy its and NASA's emerging requirements, changes in the network may be needed. NASA and DOD have held discussions over the years regarding NASA's surveillance requirements, but there is no authoritative direction, formal agreement, or clear plan on how the two agencies could consolidate their requirements for a common capability. During the past several years, NASA and DOD periodically discussed space surveillance requirements for the space station, but many proposed requirements were left to be determined and not formally provided as firm requirements to DOD. In August 1997, however, NASA provided the U.S. Space Command with an updated set of requirements for surveillance support that are more specific, comprehensive, and complete than previous requirements. Two of these requirements--detecting and tracking relatively small space objects and more accurately determining the location of such objects--cannot be met by DOD's existing surveillance network. In commenting on a draft of this report, NASA stated that a third requirement--notifying NASA within 1 hour of a space object breakup--also cannot be met. NASA has designed portions of the space station with shielding to provide protection against objects smaller than 1 centimeter. It has concluded that shielding against larger objects would be too costly. The National Science and Technology Council estimated that about 118,000 objects 1 centimeter and larger were orbiting the earth. However, DOD's surveillance network cannot routinely detect and track 110,000 (93 percent) of the objects that are estimated to be between 1 and 10 centimeters in size. The National Research Council report stated that the risk of the space station colliding with untracked debris could be lowered if more objects were tracked. The report mentioned that debris from about 0.5 to 20 centimeters in diameter was of most concern to the space station because, within this range, the debris may be too large to shield against and too small to (currently) track and avoid. Because NASA has no location information about these relatively small sized objects, it is requiring DOD, in the near term, to routinely detect, track, and catalog all space objects that are 5 centimeters and larger and have a perigee of 600 kilometers or less. Beginning in the 2002-2003 time frame, when the space station is to be completed, NASA will require DOD to detect, track, and catalog objects as small as 1 centimeter. DOD agrees that achieving the ability to detect and track objects 5 centimeters in size would be an intermediate step to meeting NASA's needs. However, DOD stated that achieving the capability to detect and track objects 1 centimeter in size would be technically challenging. The importance of the requirement to detect and track 1 centimeter space objects is linked to the effect of critical collisions between such objects and the space station. NASA estimates a 19-percent probability of critical collisions with objects larger than 1 centimeter during a 10-year period. Although not all collisions would be catastrophic, NASA estimates a 5-percent probability that such collisions would cause a catastrophic failure, resulting in the loss of a module or a crew member. The National Research Council emphasized that these calculations are far from exact because they are based on many assumptions such as the future debris environment, which could be higher or lower than estimated, and the effectiveness of shielding critical space station components. Also, the calculations exclude impacts on noncritical items that could potentially cause severe damage to the station. NASA plans to maneuver the space station to avoid collisions with those space objects that can be accurately located by DOD's surveillance network. Currently, DOD assesses the proximity of the 8,000 cataloged objects relative to an orbiting space shuttle. NASA uses these assessments to determine whether a sufficient threat exists to require a collision avoidance maneuver. Although NASA has made such maneuvers with the space shuttle, the shuttle has not been maneuvered in some instances because of concern for interference with the primary mission objective. For safety reasons, knowing the accurate location of space objects is important in deciding when to make collision avoidance maneuvers. Also, such knowledge would help avoid making unnecessary maneuvers that would be disruptive to mission objectives, such as microgravity experiments performed on the space shuttle or space station. To ensure accurate information on objects that are 1 centimeter and larger, in low-earth orbit, and with perigees 600 kilometers or less, NASA's requirements specifically call for sensor tracking to an orbital "semi-major axis" uncertainty of 5 meters or less. The purpose of this requirement is to better predict possible collisions and better decide on the need for collision avoidance maneuvers. However, DOD cannot meet this requirement because the network's sensors and processing capability and capacity are insufficient, and because DOD does not have a program to measure the orbital location accuracy of the 8,000 cataloged objects. During the 1980s and early 1990s, the U.S. and Air Force Space Commands repeatedly studied different aspects of space surveillance needs and requirements, but not in a comprehensive manner. Command representatives told us that the lack of emphasis on space surveillance during this period was due to its lower priority compared with other missions, such as ballistic missile defense. In 1994, the U.S. Space Command assessed its surveillance requirements, which had last been validated in 1985. The results showed that the requirements were loosely stated or inferred, had little supporting rationale, and did not address future threats. This assessment led to another study, completed by the Air Force Space Command in 1995, that established new space surveillance requirements. However, these requirements were never validated by the Joint Requirements Oversight Council--DOD's authoritative forum for assessing requirements for defense acquisition programs. In early 1997, the U.S. Space Command determined that the 1995 Air Force surveillance requirements contained insufficient detail and justification and, as a result, initiated another requirements review. In June 1997, the Command emphasized that space surveillance is the foundation for all functions that are performed in space and thus requested updated surveillance requirements from defense, intelligence, and civil space sector users, stating that the requirements must be quantitatively linked to the needs of the warfighter and the Command's assigned civil support responsibilities. The final product is to be a space surveillance requirements annex to the Command's space control capstone requirements document. This document, which is still in draft form, emphasizes the necessity of (1) timely space surveillance assessments relative to hostile actions in space, foreign reconnaissance satellite overflights, and operational capabilities of foreign satellites and (2) accurate information about space object size and orbital locations. Upon completion of this effort, the space surveillance requirements are to be reviewed and validated by the Joint Requirements Oversight Council. The DOD Space Architect used the U.S. Space Command's draft capstone requirements as a basis for performing its space control architecture study. The study observed that U.S. forces expect timely characterization of space threats; that is, forces expect to be warned in a timely manner when a foreign satellite is a threat to their theater of operations. However, the study concluded that, with the trends in satellite growth indicating not only more satellites but also smaller and more compact satellites (known as microsatellites), the task of distinguishing the attributes and status of orbiting objects with both ground- and space-based sensors becomes more difficult. DOD has a well-defined process for establishing its own requirements. However, because NASA is not a participant in this process and depends on DOD to provide space surveillance capabilities, it is not clear how NASA can ensure satisfaction of its surveillance requirements. First, although the 1996 National Space Policy implies that DOD should provide such surveillance capabilities, and the U.S. Space Command acknowledges its civil space sector responsibility in this area, the policy does not provide directions to ensure that DOD satisfies NASA's requirements. Second, although NASA has provided requirements to the U.S. Space Command, DOD and NASA have not reached agreement as to how or when these requirements might be satisfied. Third, the DOD Space Architect organization's study of space surveillance, which included both the defense and intelligence space sectors, noted that detecting and tracking space debris down to 1 centimeter (NASA's requirement) could be important to the safety of manned space systems, but that the requirement is not a high priority for DOD. Thus, there is no authoritative direction, formal agreement, or clear plan on how the two agencies could consolidate their requirements for a common capability. The civil and national security (defense and intelligence) space sectors have a common interest in space surveillance, and there may be an increasing interest by the commercial space sector. Better information is needed regarding the size, location, and characterization of space objects than the existing space surveillance network can provide. NASA's space surveillance requirements are commensurate with its responsibilities to ensure the safety of human space flight, but these requirements have not been acted upon by DOD. DOD's space surveillance requirements continue to be reviewed and will likely become more stringent. Unless DOD and NASA can establish a consolidated set of national security and civil space surveillance requirements, an opportunity may be missed to (1) better ensure the safety of the planned multibillion dollar space station and (2) help satisfy national security needs, including U.S. forces' future needs for space asset information. We recommend that the Secretary of Defense and the Administrator of NASA, in consultation with the Director of Central Intelligence, establish a consolidated set of governmentwide space surveillance requirements for evaluating current capabilities and future architectures to support NASA's, DOD's, and other federal agencies' space programs and surveillance information needs. DOD's plans to modernize the existing Naval Space Surveillance System (known as the Fence) and develop three new ballistic missile warning systems do not adequately consider NASA's or DOD's emerging space surveillance requirements. The Fence modernization effort would not provide an enhanced capability, but instead would only install modern components while continuing to satisfy DOD's current requirements. The development efforts for three missile warning systems do not adequately consider DOD's or NASA's emerging space surveillance requirements. Also, these four separate efforts are not sufficiently coordinated. Greater coordination could result in more informed decisions regarding the best combination of capabilities to satisfy a consolidated set of emerging national security and civil space surveillance requirements. Beginning in fiscal year 2003, the Navy tentatively plans to incrementally replace components of the Fence with modern components because of the system's age and relatively high maintenance costs. However, this effort is not currently funded and will not enhance the system's present capability to detect and track space objects smaller than about 30 centimeters. According to DOD and NASA, the Fence could be upgraded to detect most near-earth space objects larger than 1 centimeter by changing its operating radio frequency from the existing very high frequency band to the super-high frequency band and by locating it near the equator. Such an upgrade could aid in satisfying both NASA's requirement related to small-sized space objects and DOD's emerging requirement related to microsatellites. However, according to Naval Space Command officials, such an upgrade has not undergone comprehensive study. In addition, they stated that a radio frequency change (1) is not needed to satisfy existing DOD surveillance requirements and (2) would have a significant effect on the surveillance network's data processing needs. In commenting on our draft report, DOD stated that the possibility of obtaining funds to upgrade the Fence to meet NASA's 1 centimeter requirement is not high because DOD has no comparable requirement. Historically, DOD acquired various sensors to satisfy missions other than space surveillance and then capitalized on their inherent capabilities to satisfy the surveillance mission. This collateral mission concept enabled DOD to perform two missions with the same sensors. Examples included ballistic missile early warning radars to detect and track intercontinental ballistic missiles and submarine-launched ballistic missiles and other radars to track space launch vehicles. DOD's Space-Based Infrared System (SBIRS), Ground-Based Radar (GBR), and Theater High Altitude Air Defense (THAAD) radar are future ballistic missile warning systems that could contribute to performing the space surveillance function as a secondary mission. DOD plans to develop a low-earth orbit satellite component within the SBIRS program, referred to as SBIRS-Low, to provide missile tracking support to both national and theater ballistic missile defense programs. In May 1997, the Under Secretary of Defense for Acquisition and Technology testified before a congressional panel that SBIRS-Low could also perform much of the space surveillance function, allowing some existing terrestrial surveillance sensor sites to be closed and eliminating some surveillance network gaps in space coverage, such as in the Southern Hemisphere. Although DOD believes that the planned SBIRS-Low design would provide an inherent space surveillance capability, its specific capabilities for this function have not been determined. The Air Force plans to initiate SBIRS-Low development in fiscal year 1999, launch the first satellite in fiscal year 2004, and ultimately procure up to 24 or more satellites to establish an operational constellation that would provide worldwide coverage. Although the SBIRS program office has begun to investigate the feasibility of space-based space surveillance, it currently does not plan to develop the SBIRS' surveillance capabilities because the necessary operational requirements have not been established. Until these requirements are established, DOD can only point to the potential capabilities provided inherently by the ballistic missile warning design. The Army is developing two new phased-array radar systems--the GBR to support national missile defense and the THAAD radar to support theater missile defense. Army project officials stated that on the basis of limited analyses, GBR and THAAD radars each may have inherent space surveillance capabilities that could support NASA's and DOD's emerging requirements. They stated that GBR, for example, could (1) detect and track space objects that are approximately 1 centimeter or less and (2) maintain 1,000 simultaneous tracks of these objects compared with only several hundred tracks that phased-array radars in the existing surveillance network can maintain. Similarly, the officials stated that the THAAD radars could track, characterize, and discriminate objects while performing their autonomous search function. Finally, the officials stated that the GBR and THAAD radars could be used during peacetime for space surveillance while maintaining readiness for combat. As with SBIRS-Low, neither GBR nor THAAD is currently required or specifically designed to perform space surveillance functions. Army officials stated that, although the U.S. Space Command was briefed about GBR's ability to perform collateral missions, including space surveillance, the Command had not established operational requirements for space surveillance applicable to either GBR or THAAD. By fiscal year 1998, the Army plans to have a GBR prototype in operation. A national missile defense deployment decision is expected in fiscal year 2000, which may include plans for GBR deployment in 2003. Regarding THAAD, the Army currently has two test radars and plans to award an engineering and manufacturing development contract in 1999 for two radars with more capability. It expects to deploy as many as 12 mobile THAAD radars worldwide. The Air Force Space Command's 1995 space surveillance study observed that the surveillance network evolved without a master plan. The space surveillance mission did not have as high a priority as other missions, and DOD capitalized on the inherent capabilities of sensors that were designed for purposes other than surveillance. The lack of such a comprehensive plan creates difficulties in assessing operational capabilities to satisfy requirements, particularly when the need arises to evaluate emerging requirements that are increasingly stringent. The DOD Space Architect's May 1997 space control study assessed a mix of space surveillance capabilities. The study observed, for example, that a modest radio frequency enhancement to the existing Naval Space Surveillance System, costing roughly $200 million, is feasible for tracking space debris as small as 2 to 5 centimeters. The study also observed that the timing is right to evaluate the presumed inherent space surveillance capabilities of SBIRS-Low to determine if those capabilities could actually be provided. Although GBR and THAAD were not specifically addressed in the study, it indicated that a system with similar generic capability would be stressed to achieve NASA's 1 centimeter requirement. Finally, the study suggested that several technology efforts be continued to provide a hedge against an uncertain set of future space control threats and priorities. A significant point in the Space Architect's study was that NASA's 1 centimeter requirement would be both technically challenging and expensive. In its comments on our draft report, DOD stated that the requirement is not considered feasible within current budget constraints. Until the Joint Space Management Board provides directions regarding the study's results, implementation plans will not be prepared. Even then, the plans may not sufficiently address NASA's needs without agreement between DOD and NASA. NASA relies on DOD for space surveillance support, and both agencies need improved surveillance capabilities. However, four DOD systems that could provide such capabilities--the Naval Space Surveillance System, SBIRS-Low, GBR, and THAAD--lack sufficient coordination, both within DOD and between DOD and NASA. The three missile defense sensors (SBIRS-Low, GBR, and THAAD) could provide a collateral space surveillance capability, a concept DOD has successfully used over the years. In times of constrained budgets, capitalizing on ways to satisfy multiple missions with the same resources appears to be prudent. A coordinated plan between DOD and NASA that considers all existing and planned capabilities could be beneficial in making cost-effective decisions to satisfy a consolidated set of emerging national security and civil space surveillance requirements. Without a coordinated plan, DOD and NASA would not be taking advantage of potential efficiencies. The DOD Space Architect, along with NASA and the intelligence space sector, could provide a means for developing such a plan. We recommend that the Secretary of Defense and the Administrator of NASA, in consultation with the Director of Central Intelligence, develop a coordinated governmentwide space surveillance plan that (1) sets forth and evaluates all feasible alternative capabilities to support human space flight and emerging national security requirements and (2) ensures that any planned funding for space surveillance upgrades is directed toward satisfying consolidated governmentwide requirements.

Summary:
GAO reviewed the Department of Defense's (DOD) and the National Aeronautics and Space Administration's (NASA) space surveillance requirements and DOD's space surveillance capabilities, focusing on: (1) how well DOD's existing surveillance capabilities support DOD's and NASA's current and future surveillance requirements; and (2) the extent to which potential surveillance capabilities and technologies are coordinated to provide opportunities for improvements. GAO noted that: (1) DOD's existing space surveillance network is not capable of providing the information NASA needs to adequately predict collisions between space objects orbiting the earth and multibillion dollar space programs like the space station; (2) the existing network cannot satisfy DOD's emerging space surveillance requirements, which are currently under review; (3) DOD's plans--to modernize an existing surveillance network radar system and develop three new ballistic missile warning systems that could contribute to performing the surveillance function--do not adequately consider DOD's or NASA's surveillance requirements; (4) these four systems are separately managed by the Navy, the Air Force, and the Army; (5) an opportunity exists to consider these systems' potential capabilities to enhance the surveillance network to better satisfy requirements and achieve greater benefits from planned investment in space sensor technology; (6) despite NASA's dependency on DOD to provide space object information, the 1996 National Space Policy makes no provision for an interagency mechanism--either organizational or funding--to ensure that DOD's surveillance capabilities satisfy NASA's requirements; (7) overall, there is no authoritative direction, formal agreement, or clear plan on how DOD and NASA could consolidate their space surveillance requirements for a common capability; (8) a coordinated interagency plan that considers all existing and planned space surveillance capabilities could be beneficial in making cost-effective decisions to satisfy a consolidated set of national security and civil space surveillance requirements; (9) unless DOD and NASA can agree on such a plan, an opportunity may be missed to simultaneously: (a) achieve efficiencies; (b) better ensure the safety of the planned multibillion dollar space station; and (c) help satisfy national security needs, including the U.S. forces' future needs for space asset information.