United States General Accounting Office

GAO Report to Congressional Requesters

December 1997 SPACE

SURVEILLANCE

DOD and NASA Need

Consolidated

Requirements and a

Coordinated Plan

GAO/NSIAD-98-42

GAO United States

General Accounting Office

Washington, D.C. 20548

National Security and

International Affairs Division

B-275848 

December 1, 1997

The Honorable Dana Rohrabacher

Chairman

The Honorable Robert E. Cramer, Jr.

Ranking Minority Member

Subcommittee on Space and Aeronautics

Committee on Science

House of Representatives

In response to your request, this report discusses (1) the Department of Defense’s (DOD) and the

National Aeronautics and Space Administration’s (NASA) requirements for surveillance of space

objects and (2) DOD’s space surveillance capabilities to support these requirements. This report

contains recommendations to the Secretary of Defense and the Administrator of NASA.

We are sending copies of this report to the Secretaries of Defense, the Air Force, the Navy, and

the Army; the Administrator of NASA; the Directors of the Office of Management and Budget, the

Office of Science and Technology Policy, and the Central Intelligence; and other interested

congressional committees. Copies will be made available to others upon request.

If you or your staff have any questions concerning this report, please call me at (202) 512-4841.

Major contributors to this report are listed in appendix IV.

Louis J. Rodrigues

Director, Defense Acquisitions Issues
Executive Summary

Purpose During the past 40 years, 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. Knowing what

objects are in space and their locations are important because of the

(1) implications of foreign satellite threats to U.S. national security and

(2) hazards that such objects create for multibillion dollar space programs,

especially large ones such as the International Space Station.

At the request of the Chairman and Ranking Minority Member,

Subcommittee on Space and Aeronautics, House Committee on Science,

GAO is providing this report on the Department of Defense’s (DOD) and the

National Aeronautics and Space Administration’s (NASA) space surveillance

requirements and DOD’s space surveillance capabilities. GAO evaluated

(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.

Background According to a National Science and Technology Council report,1

 an

estimated 35 million manmade space objects are orbiting the earth. Of

these objects, only about 8,000 can be routinely observed by DOD’s existing

space surveillance sensors. DOD and the intelligence community 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.2 NASA is interested in accurate and timely

information on the location 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 NASA 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

network, consisting of radar and optical sensors, data processing

capabilities, and supporting communication systems, detects space

1

This Council was established by the President in 1993 to coordinate science, space, and technology

policies throughout the federal government. The President is the Council Chairman, and membership

includes the Vice President and cabinet-level and other federal agency officials. See Interagency

Report on Orbital Debris, November 1995.

2

The space control mission includes four functions: surveillance to provide awareness of all activities

in space; protection to ensure U.S. space system survivability; prevention to preclude an adversary the

use of U.S. or third-party space systems, capabilities, and products; and, when directed, negation to

deny adversaries the use of their space systems.

Page 2 GAO/NSIAD-98-42 Space Surveillance
Executive Summary

objects; tracks them to determine their orbits; and characterizes them to

determine their size, shape, motion, and type. This information is

transmitted from the sensors to two command centers for processing and

maintained in a catalog, which is used for such purposes as monitoring

foreign satellites and analyzing space debris.

Results in Brief 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 such as

the space station. Moreover, the existing network cannot satisfy DOD’s

emerging space surveillance requirements, which are currently under

review.

DOD’s plans to (1) modernize an existing surveillance network radar

system and (2) develop three new ballistic missile warning systems, which

could contribute to performing the surveillance function, do not

adequately consider DOD’s or NASA’s surveillance requirements. These four

systems are separately managed by the Navy, the Air Force, and the Army.

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.

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. 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. 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. Unless DOD and NASA

can agree on such a plan, an opportunity may be missed to simultaneously

(1) achieve efficiencies; (2) better ensure the safety of the planned

multibillion dollar space station; and (3) help satisfy national security

needs, including the U.S. forces’ future needs for space asset information.

Page 3 GAO/NSIAD-98-42 Space Surveillance
Executive Summary

Principal Findings

Existing Network Cannot

Satisfy Emerging

Surveillance Requirements

The U.S. Space Command cannot satisfy NASA’s space surveillance

requirements with the existing surveillance network. One

requirement—detecting and tracking space objects as small as 

1 centimeter—is linked to the potentially catastrophic effect of a collision

between such an object and the space station. Another

requirement—locating space objects more accurately—is not currently

possible because the network’s sensors and processing capability and

capacity are insufficient, and DOD does not have a program to measure

object location accuracy. These deficiencies necessitate an upgraded

capability to the surveillance network.

In August 1997, NASA provided surveillance requirements to the U.S. Space

Command that are commensurate with NASA’s responsibilities to ensure

the safety of human space flight. According to the NASA Administrator,

these requirements reflect NASA’s needs to minimize risk to human and

robotic space flight and assist in recovery from mishaps of both domestic

and foreign spacecraft. However, DOD and NASA have not reached

agreement regarding how to satisfy these requirements.

DOD’s existing space surveillance requirements have been repeatedly

studied and will likely become more stringent to address emerging needs

regarding future threats. DOD is concerned about timely warning to U.S.

forces when a foreign satellite becomes a threat to military operations.

With larger numbers of smaller size satellites (known as microsatellites)

expected in the future, DOD believes the space surveillance mission will

become more difficult to execute. DOD is currently reviewing its

requirements.

Potential Surveillance

Capabilities Are Not

Sufficiently Coordinated

Four systems, which are managed separately by the military services,

could be upgraded or designed to support surveillance functions. These

systems are an operational Navy-funded space surveillance system and an

Air Force- and two Army-funded developmental systems associated with

ballistic missile defense. However, there is a lack of coordination—both

within DOD and between DOD and NASA—to take advantage of these

systems’ potential contribution to space surveillance for serving both

national security and civil space sectors.

Page 4 GAO/NSIAD-98-42 Space Surveillance
Executive Summary

DOD’s Space Architect organization has a key role in evaluating national

security space missions and capabilities for achieving acquisition and

operational efficiencies.3

 Although it does not have a similar responsibility

for evaluating civil space needs, NASA could participate with the DOD Space

Architect organization in evaluating space surveillance needs from a

broader perspective.

Recommendations GAO recommends 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 and

• 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.

Agency Comments Both DOD and NASA provided written comments on a draft of this report.

Their comments appear in appendixes II and III, respectively.

DOD generally agreed with GAO’s recommendations. While DOD supports a

governmentwide group to consolidate requirements, it emphasized the

need for each organization to first establish individual requirements and

then proceed with consolidating the requirements and sharing the cost for

satisfying them. It noted that an interagency group will be required to

develop a near-term policy on cost or burden sharing and a long-term

policy for government and commercial organizations that may request

space surveillance support. Also, DOD agreed with an interagency approach

to evaluate existing capabilities, plan future architectures, and address

funding responsibilities.

Although NASA did not comment on GAO’s recommendations, it stated that,

overall, the draft report was an accurate representation of the national

requirements for space surveillance (particularly DOD’s and NASA’s) and

3

The purpose of the Space Architect organization is to consolidate the responsibilities for DOD space

missions and system architecture development into a single organization to achieve acquisition and

future operational efficiencies. The Architect also performs this function with the intelligence

community to support national security requirements.

Page 5 GAO/NSIAD-98-42 Space Surveillance
Executive Summary

DOD’s current space surveillance network capabilities. NASA emphasized

that, in August 1997, the NASA Administrator provided the U.S. Space

Command with quantified space surveillance requirements. It stated that,

although most of the near-term requirements are being met, three are not

presently being satisfied: detecting and tracking relatively small space

objects and more accurately determining the location of such objects, as

discussed in this report, and notifying NASA of a space object breakup

within 1 hour.

Concerning DOD’s and NASA’s comments about the need for a process to

address requirements, the agencies have the Aeronautics and Astronautics

Coordinating Board—a senior management review and advisory

body—that could oversee the establishment of space surveillance

requirements and the development of a space surveillance plan. The Board

exists to facilitate coordination of aeronautics and space activities of

mutual interest to DOD and NASA. It was established several years ago, and

the memorandum of agreement was renewed in 1993 by the Deputy

Secretary of Defense and the Administrator of NASA. The Director, National

Reconnaissance Office, is 1 of 18 members on the Board.

Finally, DOD stated that delaying space surveillance programs, which it has

funded to meet DOD requirements, to insert NASA’s recently provided

requirements would result in increased cost and schedule risk. GAO

recognizes that some funds may be needed for system maintenance and

modernization and therefore modified its recommendation to only address

system upgrades. GAO believes that any funding for such upgrades should

be directed toward satisfying consolidated governmentwide requirements.

Page 6 GAO/NSIAD-98-42 Space Surveillance
Page 7 GAO/NSIAD-98-42 Space Surveillance
Contents

Executive Summary 2

Chapter 1 

Introduction

10

Surveillance Network Functions 10

Surveillance Network Evolution 11

National Space Policy Guidelines 12

Increasing Attention to Space Surveillance 12

Objectives, Scope, and Methodology 14

Chapter 2 

Existing Network

Cannot Satisfy

Emerging Surveillance

Requirements

16

NASA’s Requirements to Protect the Space Station Are Stringent 16

DOD’s Requirements Are Under Review and Likely to Become

More Stringent

18

Process for Establishing Consolidated Requirements Is Not Clear 19

Conclusions 19

Recommendation 20

Chapter 3 

Potential Surveillance

Capabilities Are Not

Sufficiently

Coordinated

21

Radar System Plan Does Not Address Emerging Surveillance

Requirements

21

Missile Warning Plans Do Not Address Emerging Surveillance

Requirements

21

Lack of a Coordinated Plan 23

Conclusions 24

Recommendation 24

Appendixes Appendix I: Surveillance Network Composition and

Characteristics

26

Appendix II: Comments From the Department of Defense 28

Appendix III: Comments From the National Aeronautics and

Space Administration

32

Appendix IV: Major Contributors to This Report 36

Related GAO Products 40

Table Table I.1: Space Surveillance Sensor Locations, Types, and

Detection Ranges

27

Page 8 GAO/NSIAD-98-42 Space Surveillance
Contents

Abbreviations

DOD Department of Defense

GAO General Accounting Office

GBR Ground-Based Radar

NASA National Aeronautics and Space Administration

SBIRS Space-Based Infrared System

THAAD Theater High-Altitude Air Defense

Page 9 GAO/NSIAD-98-42 Space Surveillance
Chapter 1 

Introduction

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.1

The increasing amount of space debris creates a hazard to certain

spacecraft, especially large ones like the planned multibillion dollar

International Space Station,2

 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.

Surveillance Network

Functions

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

1

Low-earth orbits are at altitudes less than 5,500 kilometers. A geosynchronous orbit is at an altitude of

about 36,000 kilometers.

2

In Space Station: Estimated Total U.S. Funding Requirements (GAO/NSIAD-95-163, June 12, 1995), we

reported that the space station would cost about $58 billion from program inception in 1985 through

final assembly in space in June 2002. This cost estimate consisted of (1) $11.2 billion spent from 1985

through 1993 for designing and developing earlier versions; (2) $17.4 billion to be spent from 1994 to

2002 to complete assembly of the current design; and (3) $19.6 billion to be spent to 2002 for

station-related requirements, such as space shuttle launch support. In addition, $9.4 billion was

expected to be spent to 2002 by international partners, other than Russia. Finally, $45.7 billion was

estimated to support 10 years of operations after 2002. NASA is updating its cost estimates, and we are

reviewing them.

Page 10 GAO/NSIAD-98-42 Space Surveillance
Chapter 1 

Introduction

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.

Surveillance Network

Evolution

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

Page 11 GAO/NSIAD-98-42 Space Surveillance
Chapter 1 

Introduction

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.

National Space Policy

Guidelines

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.

Increasing Attention

to Space Surveillance

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.

Page 12 GAO/NSIAD-98-42 Space Surveillance
Chapter 1 

Introduction

Debris Creates Hazard to

Space Station

According to the National Research Council,3 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.

Potential for Increased

Threats to U.S. Forces

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.

3

This Council, part of the National Academy of Sciences, provides advice to the federal government on

scientific and technical matters. See Protecting the Space Station from Meteoroids and Orbital Debris,

1997.

Page 13 GAO/NSIAD-98-42 Space Surveillance
Chapter 1 

Introduction

Recent DOD and NASA

Activities Related to

Surveillance

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.4

 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.5

 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.

Objectives, Scope,

and Methodology

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.

4

This Board was established by the Secretary of Defense and the Director of Central Intelligence to

ensure that defense and intelligence needs for space systems and their terrestrial components are

satisfied within available resources, using integrated architectures to the extent possible.

5

DOD uses the term near earth to describe a range of altitudes that are similar to the National Science

and Technology Council’s definition of low earth.

Page 14 GAO/NSIAD-98-42 Space Surveillance
Chapter 1 

Introduction

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.

Page 15 GAO/NSIAD-98-42 Space Surveillance
Chapter 2 

Existing Network Cannot Satisfy Emerging

Surveillance Requirements

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.

NASA’s Requirements

to Protect the Space

Station Are Stringent

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.

Relatively Small-Sized

Space Object Information

Needed

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

Page 16 GAO/NSIAD-98-42 Space Surveillance
Chapter 2 

Existing Network Cannot Satisfy Emerging

Surveillance Requirements

have a perigee of 600 kilometers or less.1 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.

Accurate Space Object

Location Information

Needed

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

1

The perigee of an object’s orbit is the lowest point of the orbit relative to the earth.

Page 17 GAO/NSIAD-98-42 Space Surveillance
Chapter 2 

Existing Network Cannot Satisfy Emerging

Surveillance Requirements

axis” uncertainty of 5 meters or less.2 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.

DOD’s Requirements

Are Under Review and

Likely to Become

More Stringent

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.

2

Because most space objects have elliptical orbits, the longer radius of the ellipse is known as the

semi-major axis.

Page 18 GAO/NSIAD-98-42 Space Surveillance
Chapter 2 

Existing Network Cannot Satisfy Emerging

Surveillance Requirements

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.

Process for

Establishing

Consolidated

Requirements Is Not

Clear

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.

Conclusions 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.

Page 19 GAO/NSIAD-98-42 Space Surveillance
Chapter 2 

Existing Network Cannot Satisfy Emerging

Surveillance Requirements

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.

Recommendation 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.

Page 20 GAO/NSIAD-98-42 Space Surveillance
Chapter 3 

Potential Surveillance Capabilities Are Not

Sufficiently Coordinated

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.

Radar System Plan

Does Not Address

Emerging 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.

Missile Warning Plans

Do Not Address

Emerging Surveillance

Requirements

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

Page 21 GAO/NSIAD-98-42 Space Surveillance
Chapter 3 

Potential Surveillance Capabilities Are Not

Sufficiently Coordinated

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.

Infrared Satellite System 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,1

 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.

Missile Defense Radars 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

1

This testimony was presented before a joint session of the Subcommittee on Military Research and

Development and Subcommittee on Military Procurement, House Committee on National Security.

Page 22 GAO/NSIAD-98-42 Space Surveillance
Chapter 3 

Potential Surveillance Capabilities Are Not

Sufficiently Coordinated

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.

Lack of a Coordinated

Plan

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

Page 23 GAO/NSIAD-98-42 Space Surveillance
Chapter 3 

Potential Surveillance Capabilities Are Not

Sufficiently Coordinated

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.

Conclusions 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.

Recommendation 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.

Page 24 GAO/NSIAD-98-42 Space Surveillance
Page 25 GAO/NSIAD-98-42 Space Surveillance
Appendix I 

Surveillance Network Composition and

Characteristics

The space surveillance network presently includes 31 DOD and privately

owned radar and optical sensors at 16 worldwide locations, a

communications network, and primary and alternate operations centers

for data processing. Most of the sensors are mechanical tracking,

phased-array, and continuous-wave radars, but optical telescopes are also

used.

The most common radar type is a mechanical tracker with a movable

antenna, whereby energy is transmitted into space and reflected by a

space object back to the same radar antenna. A phased-array radar

consists of thousands of individual antennas that produce and steer energy

beams to different locations in space. A continuous-wave radar system

consists of several transmitters and receivers, each placed in a different

physical location across a horizontal plane. The Naval Space Surveillance

System, consisting of six receivers and three transmitters located at sites

from California to Georgia, is a continuous-wave system. Telescopes, such

as the Ground-based Electro-Optical Deep Space System, detect light

reflected from space objects and track the objects using this reflected

light.

The various network sensors’ support to the space surveillance mission

are categorized as being dedicated, collateral, or contributing. Dedicated

sensors support the space surveillance mission as their primary purpose.

Collateral sensors primarily support other missions, such as ballistic

missile warning or launch vehicle range support, but also provide space

surveillance capabilities. Contributing sensors are used under a contract

or an agreement to support the space surveillance mission only when

requested by the U.S. Space Command.

All space surveillance data needs are coordinated through the Space

Control Center, located at Cheyenne Mountain Air Station in Colorado, or

the alternate control center, located at the Naval Space Command in

Virginia. These control centers direct the network sensors to collect data

on a space object’s orbital position. Such data can provide information

about the time that the space object is observed, its angle (elevation) from

the point of observation, its direction (azimuth) from true north, and its

distance (range) from the sensor. Information about a space object’s

physical properties, such as size, shape, motion, orientation, and surface

materials, can also be obtained.

About one-third of the network sensors provide data on space objects only

in near-earth altitudes (5,875 kilometers and less), about one-third only in

Page 26 GAO/NSIAD-98-42 Space Surveillance
Appendix I 

Surveillance Network Composition and

Characteristics

deep space, and about one-third in both near earth and deep space. 

Table I.1 lists the network sensors by category, with the sensor types and

detection ranges by locations.

Table I.1: Space Surveillance Sensor

Locations, Types, and Detection

Ranges

Sensor location Sensor type Sensor detection range

Dedicated support to space surveillance mission

Diego Garcia, Indian Ocean 3 telescopes Deep space

Eglin Air Force Base, Florida 1 phased-array radar Near earth and deep space

Maui, Hawaii 6 telescopes 4 deep space and 2 near

earth and deep space

Western and southern U.S.

locations for the Naval Space

Surveillance System

1 continuous-wave radar

system

Near earth

Socorro, New Mexico 3 telescopes Deep space

Collateral support to space surveillance mission

Antigua, British West Indies 1 mechanical tracker radar Near earth

Ascension Island, South

Atlantic Ocean

2 mechanical tracker radars Near earth

Beale Air Force Base,

California

1 phased-array radar with 

2 faces

Near earth

Cape Cod Air Force Station,

Massachusetts

1 phased-array radar with 

2 faces

Near earth

Cavalier Air Force Station,

North Dakota

1 phased-array radar Near earth

Clear Air Station, Alaska 1 mechanical tracker radar Near earth

Fylingdales, England 1 phased-array radar with 

3 faces

Near earth

Oahu, Hawaii 1 mechanical tracker radar Near earth

Thule, Greenland 1 phased-array radar with 

2 faces

Near earth

Contributing support to space surveillance mission

Kwajalein, Marshall Islands 4 mechanical tracker radars Near earth and deep space

Tyngsboro, Massachusetts 3 mechanical tracker radars Near earth and deep space

Page 27 GAO/NSIAD-98-42 Space Surveillance
Appendix II 

Comments From the Department of Defense

Note: GAO comments

supplementing those in the

report text appear at the

end of this appendix.

Page 28 GAO/NSIAD-98-42 Space Surveillance
Appendix II 

Comments From the Department of Defense

Now on pp. 5 and 20.

See comment 1.

See comment 2.

See comment 3.

Page 29 GAO/NSIAD-98-42 Space Surveillance
Appendix II 

Comments From the Department of Defense

Now on pp. 5 and 24.

See comment 4.

Page 30 GAO/NSIAD-98-42 Space Surveillance
Appendix II 

Comments From the Department of Defense

The following are GAO’s comments on DOD’s letter dated October 8, 1997.

GAO Comments 1. Unless DOD and NASA reach an agreement on requirements and cost or

burden sharing for space surveillance, NASA may have to decide what

degree of risk would be acceptable to its interests if surveillance network

improvements are not made. Interagency agreements have been reached

on other programs. For example, a memorandum of agreement for the

National Polar-Orbiting Operational Environmental Satellite System was

signed by the Secretaries of Commerce and Defense and the Administrator

of NASA in 1995 that established a joint requirements process. It also

provided directions for developing acquisition, technology, operations,

funding, and organizational management plans. Regarding funding, the

agreement established that a cost-sharing approach would be used for

common requirements and that unique requirements would be funded by

the appropriate agency.

2. We made adjustments in our report to refer to the surveillance network,

where applicable, rather than just the surveillance sensors.

3. We are aware that the DOD Space Architect’s 1997 space control study

included a recommendation to separate the space surveillance function

from the missile warning function. Initially, this could take place through

procedural changes, and subsequently, through software and hardware

modifications associated with planned system upgrades. The stated

purpose was to reduce costs of surveillance that are otherwise required

for a rigorous missile warning software certification process.

4. We are aware of various joint processes and infrastructure within DOD

that could be used for plan development and coordination with other

government agencies. However, for space surveillance, NASA has an

important interest. The Aeronautics and Astronautics Coordinating

Board—a senior management review and advisory body to DOD and NASA to

facilitate coordination of aeronautics and space activities of mutual

interest—may need to address this subject.

Page 31 GAO/NSIAD-98-42 Space Surveillance
Appendix III 

Comments From the National Aeronautics

and Space Administration

Note: GAO comments

supplementing those in the

report text appear at the

end of this appendix.

Page 32 GAO/NSIAD-98-42 Space Surveillance
Appendix III 

Comments From the National Aeronautics

and Space Administration

See comment 1.

Now on p. 19.

See comment 2.

Page 33 GAO/NSIAD-98-42 Space Surveillance
Appendix III 

Comments From the National Aeronautics

and Space Administration

See comment 3.

Page 34 GAO/NSIAD-98-42 Space Surveillance
Appendix III 

Comments From the National Aeronautics

and Space Administration

The following are GAO’s comments on NASA’s letter dated October 10, 1997.

GAO Comments 1. In chapter 1, we briefly discussed DOD’s closing of certain sensor sites

that support space surveillance—the results of which apparently have not

seriously affected DOD. To the extent that the system’s margins have been

reduced, particularly relative to NASA’s requirements, interagency

consolidation of requirements and coordination of a capabilities plan is

further justified.

2. We are aware of several memorandums of agreement between NASA and

DOD. The 1996 agreement for support of the space shuttles and station is

written in general terms, dealing with working relationships and the

exchange of available information. Although such an agreement is

essential, the process for agreeing on stringent, quantified space

surveillance requirements, the quality of information to be provided, and

how surveillance network improvements are to be made and who pays for

them, still has to be addressed. As discussed in our comments to DOD’s

response on our draft report, the Aeronautics and Astronautics

Coordinating Board—a senior management review and advisory body to

DOD and NASA to facilitate coordination of aeronautics and space activities

of mutual interest—may be the proper forum for this subject.

3. We state in the report that NASA is dependent on DOD for space

surveillance.

Page 35 GAO/NSIAD-98-42 Space Surveillance
Appendix IV 

Major Contributors to This Report

National Security and

International Affairs

Division, Washington,

D.C.

Thomas J. Brew

Homer H. Thomson

James A. Elgas

Denver Office Frederick G. Day

Arthur Gallegos

Maricela Camarena

Arturo Holguin, Jr.

Page 36 GAO/NSIAD-98-42 Space Surveillance
Page 37 GAO/NSIAD-98-42 Space Surveillance
Page 38 GAO/NSIAD-98-42 Space Surveillance
Page 39 GAO/NSIAD-98-42 Space Surveillance
Related GAO Products

Space Station: Estimated Total U.S. Funding Requirements

(GAO/NSIAD-95-163, June 12, 1995).

Space Station: Delays in Dealing With Space Debris May Reduce Safety

and Increase Costs (GAO/IMTEC-92-50, June 2, 1992).

Space Program: Space Debris a Potential Threat to Space Station and

Shuttle (GAO/IMTEC-90-18, Apr. 6, 1990).

(707209) Page 40 GAO/NSIAD-98-42 Space Surveillance
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