a

GAO

United States General Accounting Office

Report to the Ranking Minority Member, 

Permanent Subcommittee on 

Investigations, Committee on 

Governmental Affairs, U.S. Senate

August 2002 CRITICAL 

INFRASTRUCTURE 

PROTECTION

Commercial Satellite 

Security Should Be 

More Fully Addressed

GAO-02-781
LIM

Why GAO Did This Study

Because the federal government

relies on commercial satellites,

security threats leading to their

disruption or loss would put

government functions (including

communications and information

transmission) at significant risk.

Accordingly, GAO was asked to

review, among other things, the

techniques used by federal

agencies to reduce the risk

associated with using

commercial satellite systems, as

well as efforts to improve

satellite system security

undertaken as part of federal

efforts in critical infrastructure

protection.

August 2002

CRITICAL INFRASTRUCTURE PROTECTION

Commercial Satellite Security Should Be

More Fully Addressed

This is a test for developing highlights for a GAO report. The full report, including GAO’s objectives, scope, methodology, and analysis is available

at www.gao.gov/cgi-bin/getrpt?GAO-02-781. For additional information about the report, contact Robert Dacey (202-512-3317). To provide comments on

this test highlights, contact Keith Fultz (202-512-3200) or E-mail HighlightsTest@gao.gov.

Highlights of GAO-02-781, a report to the Ranking Minority Member, Permanent Subcommittee on

Investigations, Committee on Governmental Affairs, United States Senate.

What GAO Recommends

To ensure that these assets are

protected from unauthorized

access and disruption, GAO

recommends that steps be taken

to promote the appropriate

development and implementation

of policy regarding the security of

satellite systems. GAO also

recommends that commercial

satellites be identified as a critical

infrastructure (or as part of an

already identified one) in the

national critical infrastructure

protection strategy.

In commenting on a draft of this

report, agencies included in our

review concurred with our

findings and recommendations. In

addition, these agencies and

private-sector entities provided

technical comments, which were

included in the report, as

appropriate.

United States General Accounting Office

What GAO Found

Although federal agencies rely on commercial satellites, federal

customers do not dominate the commercial satellite market, accounting

for only about 10 percent of it. As a result, federal customers generally

have not influenced security techniques used for commercial satellites.

Federal agencies do reduce their risk by securing those system

components under their control—the data links and communications

ground stations—but most components are typically the responsibility of

the satellite service provider: the satellite; the telemetry, tracking, and

control links; and the satellite control ground stations (see figure below).

Some federal agencies also mitigate risk by relying on redundant or

backup capabilities, such as additional satellite services.

In 1998, Presidential Decision Directive 63 was issued to improve the

federal approach to protecting our nation’s critical infrastructures (such

as telecommunications, energy, banking and finance, and transportation)

by establishing partnerships between private-sector entities and the

federal government. To date, the satellite industry has not been included

as part of this national effort. Further, federal policy governing the

security of satellite systems used by agencies addresses only those

satellites used for national security information and pertains only to

techniques associated with the links between ground stations and

satellites or links between satellites. Without appropriate

governmentwide policy to address the security of all satellite

components and of non–national-security information, federal agencies

may not, for information with similar sensitivity and criticality,

consistently (1) secure data links and communication ground stations or

(2) use satellites that have certain security controls that enhance

availability.

Commercial Satellite System Showing Components Not Controlled by Government Agencies

Source: GAO analysis.

G A O

Accountability Integrity Reliability

Highlights
Page i GAO-02-781 Commercial Satellite Security

Contents

Letter 1

Results in Brief 2

Background 4

Security Techniques Are Available to Protect TT&C and Data Links, 

Satellites, and Ground Stations 19

Federal Satellite Users Can Reduce Risks Only in Certain Areas, and 

National Policy Is Limited 25

National CIP Initiatives Addressing Satellite Security Have Been 

Limited 33

Conclusions 35

Recommendations 36

Agency Comments and Our Evaluation 36

Appendixes

Appendix I: Objectives, Scope, and Methodology 38

Appendix II: Comments from the Department of Defense 40

Appendix III: Comments from the Department of Commerce 42

Appendix IV: Comments from the National Aeronautics and Space 

Administration 45

Tables Table 1: Civilian Agency Use of Commercial Satellites 6

Table 2: Unintentional Threats to Commercial Satellite Systems 10

Table 3: Intentional Threats to Commercial Satellite Systems 12

Table 4: Security Techniques Available to Address Unintentional 

and Intentional Threats 20

Figures Figure 1: Key Components of a Satellite System 8

Figure 2: Entities with CIP Responsibilities as Outlined by

PDD 63 17

Figure 3: Commercial Satellite System Showing Components Not 

Controlled by Government Agencies 28
Contents

Page ii GAO-02-781 Commercial Satellite Security

Abbreviations

CIA Central Intelligence Agency

CIAO Critical Infrastructure Assurance Office 

CIP critical infrastructure protection

CNSS Committee on National Security Systems

DOD Department of Defense

EMP electromagnetic pulse 

EPA Environmental Protection Agency

FAA Federal Aviation Administration

FBI Federal Bureau of Investigation

FCC Federal Communications Commission 

FEMA Federal Emergency Management Agency

GPS Global Positioning System 

HHS Department of Health and Human Services

ISAC information sharing and analysis center 

NASA National Aeronautics and Space Administration

NCC National Coordinating Center for Telecommunications 

NDIA National Defense Industrial Association

NOAA National Oceanic and Atmospheric Administration

NSA National Security Agency 

NSTISSP National Security Telecommunications and Information 

Systems Security Policy 

NTIA National Telecommunications and Information Administration 

NTISSP National Telecommunications and Information Systems 

Security Policy 

OSTP Office of Science and Technology Policy

PDD Presidential Decision Directive

RF radio frequency 

TT&C tracking, telemetry, and control
Page 1 GAO-02-781 Commercial Satellite Security

United States General Accounting Office

Washington, D.C. 20548

A

August 30, 2002 Letr

The Honorable Susan Collins

Ranking Minority Member

Permanent Subcommittee on Investigations

Committee on Governmental Affairs

United States Senate

Dear Senator Collins:

Government and private-sector entities rely on satellites for services such 

as communication, navigation, remote sensing, imaging, and weather and 

meteorological support. Although the government owns satellites, it also 

relies for certain services on satellites owned and operated by commercial 

satellite service providers. For example, the Department of Defense (DOD) 

typically relies on commercial satellites to fulfill its communications and 

information transmission requirements for non–mission-critical data and to 

augment its military satellite capabilities. The importance of commercial 

satellites for DOD is evident during times of conflict: according to a DOD 

study, commercial communications satellites were used in 45 percent of all 

communications between the United States and the Persian Gulf region 

during Desert Shield/Desert Storm.1

 Further, the federal government’s 

reliance on commercial satellites is expected to grow. 

The commercial satellite industry is also a critical component of the 

worldwide and national economy: the industry generated $85 billion in 

revenue in 2000. Accordingly, disruption of satellite services, whether 

intentional or not, can have a major adverse economic impact. One 

indication of the importance of satellite services was provided in 1998 by 

the failure of the Galaxy IV satellite, which disrupted 80 to 90 percent of 45 

million pagers across the United States for 2 to 4 days and blocked credit 

card authorization at point-of-sale terminals (such as gasoline pumps). 

Satellites are vulnerable to various threats. Protecting satellite systems 

against these threats requires attention to (1) the satellite; (2) the satellite 

control ground stations, which perform tracking and control functions to 

ensure that satellites remain in the proper orbits and which monitor 

satellite performance; (3) the communications ground stations, which 

1

National Air Intelligence Center, Threats to U.S. Military Access to Space, Document 1422-

0989-98 (Wright Patterson Air Force Base, Ohio).
Page 2 GAO-02-781 Commercial Satellite Security

process the data being sent to and from satellites; and (4) communications 

links between satellites and ground stations—both those that transmit the 

tracking and control information and those that transmit the data. Security 

threats to any part of the system could put government and commercial 

functions at significant risk. Accordingly, at your request, we reviewed 

(1) what security techniques are available to protect satellite systems from 

unauthorized use, disruption, or damage; (2) how federal agencies reduce 

the risk associated with their use of commercial satellite systems; and 

(3) what federal critical infrastructure protection (CIP) efforts are being 

undertaken to address satellite system security through improved 

government and private-sector cooperation. To accomplish these 

objectives, we reviewed technical documents, policy, and directives and 

interviewed pertinent officials from federal agencies and the private sector 

involved in developing, operating, maintaining, and protecting satellite 

systems. Appendix I provides further details on our objectives, scope, and 

methodology.

Results in Brief Techniques to protect satellite systems from unauthorized use and 

disruption include the use of robust hardware on satellites, physical 

security and logical access controls2

 at ground stations, and encryption of 

the signals for tracking and controlling the satellite and of the data being 

sent to and from satellites. Commercial satellite service providers stated 

that they provide some of these security techniques to meet most of their 

customers’ security requirements and that they base their decisions on 

business objectives. For example, commercial satellite providers stated 

that they use backup satellites and redundant satellite features to ensure 

availability. However, commercial satellite providers generally do not use 

the more stringent techniques used in national security satellites for 

protection against deliberate disruption and exploitation. 

When using commercial satellites, federal agencies reduce risks by 

securing the data links and ground stations that send and receive data. 

However, federal agencies do not control the security of the tracking and 

control links, satellites, or tracking and control ground stations, which are 

typically the responsibility of the satellite service provider. Further, 

although the federal government relies on commercial satellites, federal 

2

Logical access controls involve the use of computer hardware and software to prevent or 

detect unauthorized access by requiring users to input user identification numbers (IDs), 

passwords, or other identifiers that are linked to predetermined access privileges. 
Page 3 GAO-02-781 Commercial Satellite Security

customers make up only about 10 percent of the commercial satellite 

market and accordingly have had limited influence over security 

techniques employed by commercial satellite service providers. To mitigate 

risk, some federal agencies also rely on redundant or backup capabilities, 

such as additional satellite services. Aspects of satellite system security 

have been addressed in federal policy, but this policy is limited because it 

pertains only to satellite and supporting systems that are used for national 

security information, addresses only techniques associated with the links, 

and does not have an enforcement mechanism. Without appropriate 

governmentwide policy to address the security of all satellite components 

and of non–national-security information, federal agencies may not, for 

information with similar sensitivity and criticality, consistently (1) secure 

data links and communication ground stations or (2) use satellites that 

have certain security controls that enhance availability. Recent initiatives 

by the Executive Branch have acknowledged these policy limitations, but 

we are not aware of specific actions to address them.

It is important to our nation’s economy and security to protect against 

attacks on its computer-dependent critical infrastructures (such as 

telecommunications, energy, and transportation), many of which are 

privately owned. In 1998, Presidential Decision Directive 63 was issued to 

improve the federal approach to protecting our nation’s critical 

infrastructures by establishing partnerships between private-sector entities 

and the federal government. However, the satellite industry has not been 

included as part of this national effort, and there are no plans to include it. 

In addition, the July 2002 national strategy for homeland security does not 

suggest that the satellite industry be included in the approach to protecting 

our critical infrastructures.3

 In light of the nation’s growing reliance on 

commercial satellites to meet military, civil, and private-sector 

requirements, omitting satellites from our nation’s approach leaves a 

critical aspect of our nation’s infrastructures without focused attention. 

Because of the importance of the satellite industry to our nation, we 

recommend that steps be taken to promote appropriate revisions to 

existing policy and the development of new policy regarding the security of 

satellite systems, to ensure that federal agencies appropriately address the 

use of commercial satellites, including the sensitivity of information, 

security techniques, and enforcement mechanisms. In addition, we are 

3

Office of Homeland Security, National Strategy for Homeland Security (Washington, D.C.: 

July 2002).
Page 4 GAO-02-781 Commercial Satellite Security

recommending that commercial satellites be identified as a critical 

infrastructure sector (or as part of an already identified critical 

infrastructure sector) in the national CIP strategy, to help ensure that these 

assets are protected from unauthorized access and disruption. 

We received written comments on a draft of this report from the 

Department of Defense; the National Oceanic and Atmospheric 

Administration, Department of Commerce; and the National Aeronautics 

and Space Administration. The Departments of Defense and Commerce 

and the National Aeronautics and Space Administration concurred with our 

findings and recommendations (see apps. II, III, and IV, respectively) and 

provided technical comments that have been incorporated in the report, as 

appropriate (some of these technical comments are reproduced in the 

appendixes). We received technical oral comments from officials from the 

Critical Infrastructure Assurance Office, Department of Commerce; 

Federal Aviation Administration, Department of Transportation; Office of 

Management and Budget; and United States Secret Service, Department of 

Treasury; in addition, we received written and oral technical comments 

from five participating private-sector entities. Comments from all these 

organizations have been incorporated into the report, as appropriate. 

Background Satellites provide many significant services, including communication, 

navigation, remote sensing, imaging, and weather and meteorological 

support. Satellites support direct radio communication and provide 

television broadcast and cable relay services, as well as home reception. 

Satellite services also support applications such as mobile and cellular 

communication, telemedicine, cargo tracking, point-of-sale transactions, 

and Internet access. Satellites also provide redundancy and backup 

capabilities to ground-based communications, as was demonstrated after 

the events of September 11, 2001, when satellites provided critical 

communications while ground-based lines were unavailable. 
Page 5 GAO-02-781 Commercial Satellite Security

The commercial satellite industry includes manufacturers, the launch 

industry, service providers, and ground equipment manufacturers. 

Manufacturers design and build satellites, supporting systems, and ground 

stations. The launch industry uses launch vehicles, powered by rocket 

engines, to place satellites in orbit. Once commercial satellites are in orbit, 

they are operated by service providers, who lease available services. 

Commercial satellite service clients include telecommunication 

companies, television networks, financial institutions, major retailers, 

Internet service providers, and governments. Some companies resell leased 

satellite services to their clients. For example, major telecommunication 

companies sometimes include satellite services in their product line. 

Ground equipment manufacturers build and sell the items needed to use 

satellite services, such as ground station hardware (antennas), data 

terminals, mobile terminals (truck-mounted units), and consumer 

electronics (satellite phones). For the year 2000, the commercial satellite 

industry generated revenues of $85.1 billion:4

 $17.2 billion for satellite 

manufacturing, $8.5 billion for the launch industry,5

 $41.7 billion for 

satellite services, and $17.7 billion for ground equipment manufacturing,6

according to an industry association.

Federal agencies also own and operate satellites. For example, the U.S. 

military and intelligence communities have satellites to provide capabilities 

for reconnaissance, surveillance, early warning of missile launches, 

weather forecasts, navigation, and communications. In addition, some 

federal civilian agencies own satellites that are used for communications, 

scientific studies, and weather forecasting.

Further, federal agencies use commercial satellites for services such as 

communications, data transmission, and remote sensing. For example, 

DOD typically relies on commercial satellites to fulfill its communications 

and information transmission requirements for non–mission-critical data 

and to augment its military satellite capabilities. The National Defense 

Industrial Association (NDIA) reported in December 1998 that the 

government’s overall use of commercial satellites for communications and 

4

All revenues include payments made to subcontractors.

5

The amount for launch services includes revenues from both government-owned and 

commercially owned payloads.

6

The manufacturing indicators include amounts from commercial companies manufacturing 

for both government and commercial customers.
Page 6 GAO-02-781 Commercial Satellite Security

remote sensing is expected to grow significantly because of increased 

communications requirements. According to a DOD official, the 

department’s reliance on commercial satellites is expected to grow through 

2020. After 2020, DOD officials anticipate that commercial satellites will 

provide only surge capacity, as additional military satellites are expected to 

be operational. In addition to the U.S. military, several civilian government 

agencies also rely on commercial satellite systems. Table 1 provides brief 

descriptions of the use of commercial satellites by four civilian agencies 

included in our review. 

Table 1: Civilian Agency Use of Commercial Satellites

Source: Cited agencies. 

Collectively, the federal government does not dominate the commercial 

satellite market. According to commercial satellite industry officials, the 

revenue provided to the satellite industry by the federal government 

represents about 10 percent of the commercial satellite market. 

Agency Use of commercial satellites

National Aeronautics and Space 

Administration

To serve as an alternative means of transmitting 

launch commands and scientific data when 

there are geographical limitations to terrestrial 

communications networks 

United States Secret Service To provide, on a limited basis, communications 

when other methods are not available 

Federal Aviation Administration To transmit corrected Global Positioning 

System data to aircraft and for remote location 

air traffic control communications

National Oceanic and Atmospheric 

Administration/ 

National Weather Service

To disseminate imagery, graphic, and text data 

on weather conditions around the earth
Page 7 GAO-02-781 Commercial Satellite Security

However, the importance of commercial satellites for government 

operations is evident during times of conflict. For example, according to a 

DOD study, commercial communications satellites were used in 45 percent 

of all communications between the United States and the Persian Gulf 

region during Desert Shield/Desert Storm. Further, during operations in 

Somalia from December 1992 through March 1994, U.S. military and 

commercial satellite coverage was not available, so Russian commercial 

satellites were used. DOD currently reports approximately 50 percent 

reliance on commercial satellites for wideband services,7

 which are leased 

through the Defense Information Systems Agency’s Commercial Satellite 

Communications Branch.8

The commercial satellite industry is a global industry that includes many 

foreign-owned corporations as well as partnerships between U.S. and 

foreign corporations. As a result, the U.S. government depends on foreign 

and international companies. For example, some commercial space 

systems of foreign origin are used by the U.S. military for imagery and 

communications support. NDIA reported that foreign ownership of 

satellites is expected to grow and predicted that by 2010, 80 percent of 

commercial communication satellite services could be provided by foreignowned companies. This globalization of the satellite industry could affect 

the availability of commercial satellite systems to U.S. government or 

commercial entities through frequency allocations, tariffs, politics, and 

international law. 

Satellites Operate through a 

System of Links and Ground 

Stations

A satellite system consists of ground stations, tracking and control links 

(commonly referred to as the tracking, telemetry, and control (TT&C) 

links) and data links, and satellites. Figure 1 illustrates the basic satellite 

system components.

7

Wideband encompasses data rates greater than 64 kilobits per second.

8

The Defense Information Systems Agency’s Commercial Satellite Communications Branch 

is responsible for leasing commercial satellite services for DOD.
Page 8 GAO-02-781 Commercial Satellite Security

Figure 1: Key Components of a Satellite System

Source: GAO analysis.

As the figure shows, two kinds of ground stations are associated with 

satellites: control stations and communications stations. Control stations 

perform tracking and control functions to ensure that satellites remain in 

the proper orbits (commonly referred to by the industry as “station 

keeping”) and to monitor their performance. Communications ground 

stations process imagery, voice, or other data and provide, in many cases, a 

link to ground-based terrestrial network interconnections. 
Page 9 GAO-02-781 Commercial Satellite Security

The links between the two types of ground stations and the satellites are 

referred to by their function: TT&C and data links. TT&C links exchange 

commands and status information between control ground stations and 

satellites. Data links exchange communications, navigation, and imaging 

data between communications ground stations and satellites. As shown in 

figure 1, links are also distinguished by the direction of transmission: 

uplinks go from Earth to space, and downlinks from space to Earth. 

Satellites can also communicate with each other; these links are referred to 

as cross-links.

The final component of the system is the satellite. Every satellite has a 

“payload” and a “bus.” The payload contains all the equipment a satellite 

needs to perform its function, and it differs for every type of satellite. For 

example, the payload for a weather satellite includes cameras to take 

pictures of cloud formations, while the payload for a communications 

satellite includes transponders to relay data (for example, television or 

telephone signals).9

 The bus carries the payload and additional equipment 

into space and provides electrical power, computers, and propulsion to the 

entire spacecraft. A satellite can serve simply as a relay between a source 

and a destination (for example, a communications satellite), or it can 

perform processing of data and communicate the data to a 

communications ground station (for example, an imaging satellite). 

Satellite Systems Are 

Vulnerable to a Range of 

Threats

Satellite systems face unintentional threats to all parts of the system; such 

threats can be ground-based, space-based, and interference-oriented. The 

probability of these threats occurring and the difficulty of exploiting these 

vulnerabilities vary. Table 2 displays some of these threats and the 

vulnerable components.

9

A transponder is an automatic device that receives, amplifies, and retransmits a signal on a 

different frequency. 
Page 10 GAO-02-781 Commercial Satellite Security

Table 2: Unintentional Threats to Commercial Satellite Systems

Source: DOD and GAO analysis.

Ground stations are vulnerable to damage or destruction by natural 

terrestrial threats such as earthquakes, floods, thunderstorms, lightning, 

dust storms, heavy snows, tropical storms, tornadoes, corrosive sea spray, 

and salt air. In addition, they could also be affected by natural conditions 

and environmental hazards, such as air pollution and adverse temperature 

environments, as well as power outages. 

Satellites are physically vulnerable to space-based environmental 

anomalies resulting from natural conditions and man-made artifacts. 

Space-based threats include solar and cosmic radiation and related 

phenomena, solar disturbances, temperature variations, and natural 

objects (meteoroids and asteroids). In addition, the growing number of 

satellites is contributing to the problem of space “junk” (spacecraft and 

debris). As of May 2002, DOD identified over 9,000 man-made objects in 

space, including active satellites. As additional satellites are developed and 

deployed, DOD officials stated that the threat of collisions caused by the 

proliferation of satellites and accompanying debris could increase. 

Type of threat Vulnerable satellite system components

Ground-based:

Natural occurrences (including 

earthquakes and floods; adverse 

temperature environments)

Ground stations; TT&C and data links

Power outages

Space-based:

Space environment (solar, cosmic 

radiation; temperature variations)

Satellites; TT&C and data links

Space objects (including debris)

Interference-oriented:

Solar activity; atmospheric and solar 

disturbances

Satellites; TT&C and data links

Unintentional human interference 

(caused by terrestrial and space-based 

wireless systems) 
Page 11 GAO-02-781 Commercial Satellite Security

Links are vulnerable both to natural conditions (in space and in the 

atmosphere) and to congestion. Links can be severely degraded by the 

effects of solar activity and atmospheric and solar disturbances. Both 

orbital and spectral congestion are a threat to links (as well as to 

satellites).10 Such congestion may restrict the future use of potential orbits 

and frequencies and cause unintentional interference to satellite services. 

According to one commercial service provider, satellite service providers 

worldwide work together to resolve interference problems, which are 

common. In addition, commercial satellite interference is regulated both 

internationally and nationally. The International Telecommunication Union 

specifies interference resolution policies and procedures, including those 

for harmful interference.11 Further, within the United States, the Federal 

Communications Commission (FCC)12 has the capability to track the 

location of interference, at a service provider’s request. Also, service 

providers told us that they could locate and identify unintentional or 

unauthorized users through a technique called triangulation. Once an 

unauthorized user is located, a commercial service provider can jam that 

user’s signal if the user cannot be persuaded to stop using the satellite. 

However, according to industry officials, typically an unauthorized user 

would be identified, located, and contacted through a combination of 

industry and government resources before such jamming would be needed.

In addition, satellite systems are vulnerable to many forms of intentional 

human attacks that are intended to destroy ground stations and satellites or 

interfere with the TT&C links, data links, and cross-links. According to 

DOD and the private sector, the probability of these threats occurring and 

10The greatly increasing number of commercial and military communications systems 

worldwide, including the growing number of satellites, is putting a high demand on certain 

frequency spectra. Orbital/spectral congestion may restrict the future use of potential orbits 

and frequencies, further complicate and lengthen host nation approval and landing rights 

processes, and require more sophisticated systems in terms of frequency agility, antennas, 

bandwidth-efficient modulation, and so forth to maximize flexibility. Such flexibility 

minimizes future risks arising from changes in spectrum allocation and the electromagnetic 

environment.

11The International Telecommunication Union is an international organization within the 

United Nations system in which governments and the private sector work together to 

coordinate the operation of telecommunication networks and services and advance the 

development of communications technology.

12The Federal Communications Commission is an independent U.S. government agency. The 

FCC was established by the Communications Act of 1934 and is charged with regulating 

interstate and international communications by radio, television, wire, satellite, and cable. 

The FCC's jurisdiction covers the 50 states, the District of Columbia, and U.S. possessions.
Page 12 GAO-02-781 Commercial Satellite Security

the difficulty of exploiting these vulnerabilities vary. Table 3 shows some of 

these intentional threats.

Table 3: Intentional Threats to Commercial Satellite Systems 

Source: GAO analysis.

All types of ground stations are potentially vulnerable to threats of physical 

attack and sabotage. These threats could target all satellite ground 

components, including launch facilities, command and control facilities, 

and supporting infrastructures. 

Space-based threats to satellites are proliferating as a result of the growing 

availability of technology around the world. According to DOD, potential 

space-based weapons include interceptors, such as space mines and 

orbiting space-to-space missiles, and directed-energy weapons. Directedenergy weapons include ground-based, airborne, and space-based weapons 

that use laser energy to damage or destroy satellite services, and nuclear 

weapons that generate nuclear radiation and electronic pulses, resulting in 

direct damage to the orbital electronics by the primary and secondary 

effects of a detonation.

Ground stations, links, and supporting communications networks are all 

vulnerable to cyber attacks. Potential cyber attacks include denial of 

service, malicious software, unauthorized monitoring and disclosure of 

sensitive information (data interception), injection of fake signals or traffic 

Type of threat Vulnerable satellite system components

Ground-based:

Physical destruction Ground stations; communications networks

Sabotage All systems

Space-based (anti-satellite):

Interceptors (space mines and space-tospace missiles)Satellites

Directed-energy weapons (laser energy, 

electromagnetic pulse)

Satellites; TT&C and data links 

Interference and content-oriented:

Cyber attacks (malicious software, denial 

of service, spoofing, data interception, 

and so forth)

All systems and communications networks

Jamming All systems
Page 13 GAO-02-781 Commercial Satellite Security

(“spoofing”), and unauthorized modification or deliberate corruption of 

network information, services, and databases. For example, malicious 

software (such as computer viruses) can be (1) implanted into computer 

systems during development or inserted during operations; (2) used to 

manipulate network protocols, deny data or service, destroy data or 

software, and corrupt, modify, or compromise data; and (3) used to attack 

processor-controlled transmission equipment, control systems, or the 

information being passed. 

Links are particularly susceptible to electronic interference threats capable 

of disrupting or denying satellite communications. These threats include 

spoofing and jamming. A spoofer emits false, but plausible, signals for 

deception purposes. If false commands could be inserted into a satellite’s 

command receiver (spoofing the receiver), they could cause the spacecraft 

to tumble or otherwise destroy itself. It is also feasible to insert false 

information or computer viruses into the terrestrial computer networks 

associated with a space system, either remotely or through an on-site 

connection. Such an attack could lead to space system degradation or even 

complete loss of spacecraft utility.

A jammer emits noise-like signals in an effort to mask or prevent the 

reception of desired signals and can be used to disrupt uplinks, downlinks, 

and cross-links. An uplink jammer attempts to inject noise or some other 

signal into the targeted satellites’ uplink receivers. In general, an uplink 

jammer must be roughly as powerful as the emitter associated with the link 

being jammed. 

Downlink jamming attempts to inject noise or some other signal directly 

into earth terminal receivers. The targets of downlink jammers are groundbased satellite data receivers, ranging from large fixed ground sites to 

handheld Global Positioning System (GPS) user terminals. Since downlink 

jammers have a range advantage over the space-based emitters, they can 

often be much less powerful. Downlink jamming is generally easier to 

accomplish than uplink jamming, since very low-power jammers are often 

suitable. Since a downlink may be received by multiple earth terminals, it is 

often more difficult to jam more than a few earth terminals through 

downlink jamming than through uplink jamming, especially if the receiver 

terminals are dispersed across a significant geographical area. 

A cross-link jammer attempts to inject noise or some other signal between 

two satellites communicating directly with each other. Because it is 

considered the most complex and difficult approach to satellite jamming, 
Page 14 GAO-02-781 Commercial Satellite Security

according to a DOD document,13 cross-link jamming is considered a lower 

probability threat than uplink and downlink jamming. 

Satellite Vulnerabilities 

Have Led to Disruptions 

Satellite services have been disrupted or denied as a result of system 

vulnerabilities. Below is a list of satellite-related incidents that have been 

publicly reported in which services were interrupted unintentionally or 

intentionally because of satellites’ vulnerabilities to jamming and 

equipment failure: 

• In April 1986, an insider, working alone under the name “Captain 

Midnight” at a commercial satellite transmission center in central 

Florida, succeeded in disrupting a cable network’s eastern uplink feed to 

the Galaxy I satellite. Although this event was a minor annoyance, it had 

the potential for disrupting services to satellite users. 

• Starting in 1995, MED-TV, a Kurdish satellite channel, was intentionally 

jammed (and eventually had its license revoked) because its broadcasts 

promoted terrorism and violence.

• In 1997, while a GPS transmitter was being tested on the ground, it 

unintentionally interfered with the GPS receivers of a commercial 

aircraft in the area. The plane temporarily lost all of its GPS information. 

• In 1997, Indonesia intentionally interfered with and denied the services 

of a commercial satellite belonging to the South Pacific island kingdom 

of Tonga because of a satellite orbital slot dispute.

• In 1998, the failure of PANAMSAT’s Galaxy IV satellite, attributable to an 

on-board processor anomaly, disabled 80 to 90 percent of 45 million 

pagers across the United States for 2 to 4 days, leaving approximately 70 

percent of a major oil company’s customers without the ability to pay 

for services at the pump.

13Department of Defense, Advanced Military Satellite Communications Capstone 

Requirements (Colorado Springs, Colo.: Apr. 24, 1998).
Page 15 GAO-02-781 Commercial Satellite Security

Critical Infrastructure 

Protection Policy Addresses 

Information Security of Key 

Sectors

Recognizing that our nation’s critical infrastructures, including 

telecommunications, energy, banking and finance, transportation, and 

satellites, are the foundation of our economy, national security, and quality 

of life, in October 1997 the President’s Commission on Critical 

Infrastructure Protection issued a report recommending several measures 

to achieve a higher level of protection of critical infrastructures. These 

measures included industry cooperation and information sharing, the 

creation of a national organization structure, a revised program of research 

and development, a broad program of awareness and education, and 

reconsideration of laws related to infrastructure protection. The report 

also described the potentially devastating implications of poor information 

security from a national perspective. The report stated that a 

comprehensive effort would need to “include a system of surveillance, 

assessment, early warning, and response mechanisms to mitigate the 

potential for cyber threats.”14

Presidential Decision Directive (PDD) 63, issued in 1998 to improve the 

federal government’s approach to critical infrastructure protection (CIP), 

describes a strategy for cooperative efforts by government and the private 

sector to protect critical computer-dependent operations. The directive 

called on the federal government to serve as a model of how infrastructure 

assurance is best achieved, and it designated lead agencies to work with 

private-sector and government entities. To accomplish its goals, PDD 63 

designated and established organizations to provide central coordination 

and support, including

• the Critical Infrastructure Assurance Office (CIAO), an interagency 

office that is housed in the Department of Commerce, which was 

established to develop a national plan for CIP on the basis of 

infrastructure plans developed by the private sector and federal 

agencies; and 

• the National Infrastructure Protection Center, an organization within the 

FBI, which was expanded to address national-level threat assessment, 

warning, vulnerability, and law enforcement investigation and response. 

14Report of the President’s Commission on Critical Infrastructure Protection, Critical 

Foundations: Protecting America’s Infrastructures (October 1997).
Page 16 GAO-02-781 Commercial Satellite Security

To ensure coverage of critical sectors, PDD 63 also identified eight privatesector infrastructures and five special functions; information and 

communication is one of the eight infrastructures identified. Further, the 

directive designated lead federal agencies to work with the private-sector 

entities. For example, Commerce is the lead agency for the information and 

communication sector (the responsible organization within Commerce is 

the National Telecommunications and Information Administration), and 

the Department of Energy is the lead agency for the electrical power 

industry. Similarly, for special function areas, DOD is responsible for 

national defense, and the Department of State is responsible for foreign 

affairs. 

To facilitate private-sector participation, PDD 63 also encouraged creation 

of information sharing and analysis centers (ISACs) that could serve as a 

mechanism for gathering, analyzing, and appropriately sanitizing and 

disseminating information to and from infrastructure sectors and the 

federal government through the FBI’s National Infrastructure Protection 

Center.15 Although most of the ISACs are operated by private-sector 

organizations, the telecommunications ISAC is operated by a government 

entity, the National Coordinating Center for Telecommunications (NCC), 

which is part of the National Communications System.16 In September 2001, 

we reported that six ISACs within five infrastructures had been established 

to gather and share information about vulnerabilities, attempted intrusions, 

and attacks within their respective infrastructure sectors and to meet 

specific sector objectives.17 In addition, at that time, we reported that the 

formation of at least three more ISACs for various infrastructure sectors 

was being discussed. Figure 2 displays a high-level overview of several 

organizations with CIP responsibilities, as outlined by PDD 63.

15See U.S. General Accounting Office, Critical Infrastructure Protection: Significant 

Challenges in Developing National Capabilities, GAO-01-323 (Washington, D.C.: Apr. 25, 

2001) for our latest report on the progress of the National Infrastructure Protection Center.

16In 1963, the National Communications System was established by presidential 

memorandum as a federal interagency group responsible for national security and 

emergency preparedness telecommunications. These responsibilities include planning for, 

developing, and implementing enhancements to the national telecommunications 

infrastructure, which now includes the Internet, to achieve effectiveness in managing and 

using national telecommunication resources to support the federal government during any 

emergency. 

17U.S. General Accounting Office, Combating Terrorism: Selected Challenges and Related 

Recommendations, GAO-01-822 (Washington, D.C.: Sept. 20, 2001).
Page 17 GAO-02-781 Commercial Satellite Security

Figure 2: Entities with CIP Responsibilities as Outlined by PDD 63

Source: CIAO.

The most recent federal cyber CIP guidance was issued in October 2001, 

when President Bush signed Executive Order 13231, Critical 

Infrastructure Protection in the Information Age, which continues many 

PDD 63 activities by focusing on cyber threats to critical infrastructures 

and creating the President’s Board on CIP to coordinate cyber-related 

federal efforts. The Special Advisor to the President for Cyberspace 

Security chairs the board. 

In July 2002, the President issued a national strategy for homeland security 

that identifies 14 industry sectors, including the 8 identified in PDD 63. The 

additional 6 are agriculture, food, defense industrial base, chemical 

industry and hazardous materials, postal and shipping, and national 

monuments and icons.18

18Office of Homeland Security, National Strategy for Homeland Security (July 2002). 
Page 18 GAO-02-781 Commercial Satellite Security

Current Space Policy 

Addresses Aspects of 

Federal Uses of Commercial 

Satellites

The U.S. national space policy provides goals and guidelines for the U.S. 

space program, including the use of commercial satellites. In February 

1991, the President issued National Space Policy Directive 3, which 

requires U.S. government agencies to use commercially available space 

products and services to the fullest extent feasible. Presidential Decision 

Directive 49, dated September 19, 1996, provides goals for the U.S. space 

program and establishes space guidelines. For example, a guideline 

regarding the commercial space industry stated that U.S. government 

agencies shall purchase commercially available space goods and services 

to the fullest extent feasible, and that, except for reasons of national 

security or public safety, they shall not conduct activities with commercial 

applications that preclude or deter commercial space activities. Neither the 

National Space Policy Directive 3 nor PDD 49 specifically addresses the 

security of satellite systems used by federal agencies. However, PDD 49 

states that critical capabilities necessary for executing space missions must 

be ensured. Security of satellite systems has been addressed in policy 

documents issued by the National Security Telecommunications and 

Information Systems Security Committee (recently renamed the 

Committee on National Security Systems). The initial policy was set forth 

in National Policy on Application of Communications Security to U.S. 

Civil and Commercial Space Systems, National Telecommunications and 

Information Systems Security Policy (NTISSP) No. 1 (June 17, 1985), 

which governed the protection of command and control uplinks for 

government-used satellites other than military. This policy, which applies to 

space systems launched 5 years from the policy date (June 17, 1985), limits 

government and government contractor use of U.S. civil and commercial 

satellites to those systems using accepted techniques to protect the 

command and control uplinks. 

In January 2001, a new policy governing satellite system security was 

issued, superseding NTISSP No. 1: National Information Assurance (IA) 

Policy for U.S. Space Systems, National Security Telecommunications 

and Information Systems Security Policy (NSTISSP) No. 12. NSTISSP 

No. 12, which focuses on systems used for U.S. national security 

information, aims to ensure that information assurance19 is factored into 

“the planning, design, launch, sustained operation, and deactivation of 

19Information assurance refers to information operations intended to protect and defend 

information and information systems by ensuring their availability, integrity, authentication, 

confidentiality, and nonrepudiation. This includes providing for restoration of information 

systems by incorporating protection, detection, and reaction capabilities.
Page 19 GAO-02-781 Commercial Satellite Security

federal and commercial space systems used to collect, generate, process, 

store, display, or transmit and receive such information.” The policy also 

includes a provision addressing commercial imagery satellites that may be 

used to satisfy national security requirements during periods of conflict or 

war. The policy states that approved U.S. cryptographies shall be used to 

provide confidentiality for (1) command and control uplinks, (2) data links 

that transmit national security information between the ground and the 

space platforms, (3) cross-links between space platforms, and

(4) downlinks from space platforms to mission ground or processing 

centers.20

Security Techniques 

Are Available to 

Protect TT&C and Data 

Links, Satellites, and 

Ground Stations 

A range of security techniques is available for protecting satellite systems: 

for example, using encryption on TT&C and data links, using robust parts 

on the satellites, and applying physical and cyber security controls at the 

ground stations. The application of these techniques varies across federal 

agencies and the private sector. Commercial satellite service providers 

typically use some of these security techniques to meet most of their 

customers’ security requirements, and they base their decisions on 

business objectives. Generally, the military applies more stringent security 

techniques to their satellites than do civilian agencies or the private sector. 

Table 4 provides an overview of security techniques by satellite system 

component. 

20Approved U.S. cryptographies are hardware, firmware, or software implementations of 

algorithms that have been reviewed and approved by the National Security Agency, the 

purposes of which are to provide authentication or confidentiality for national security 

information or systems.
Page 20 GAO-02-781 Commercial Satellite Security

Table 4: Security Techniques Available to Address Unintentional and Intentional Threats 

Source: GAO analysis.

Various Techniques Can 

Protect TT&C and Data 

Links

Techniques to protect satellite links include the use of encryption, highpower radio frequency (RF) uplinks, spread spectrum communications, 

and a digital interface unique to each satellite. Commercial satellite service 

providers, federal satellite owners and operators, and customers stated 

that they typically use at least one of these techniques. Usually, only the 

military uses spread spectrum techniques. 

Both TT&C and data links can be protected by encryption: generally, for 

TT&C links, the tracking and control uplink is encrypted, while the 

telemetry downlink is not. Encryption is the transformation of ordinary 

data (commonly referred to as plaintext) into a code form (ciphertext) and 

back into plaintext, using a mathematical process called an algorithm. 

Encryption can be used on data to (1) hide information content, (2) prevent 

undetected modification, and (3) prevent unauthorized use. 

Different levels of encryption provide different levels of protection, 

including encryption approved by the National Security Agency (NSA) that 

is used for national security information. NSTISSP No. 12 requires 

approved U.S. cryptographies on TT&C and data links for U.S. space 

systems transmitting national security information. For satellite systems 

transmitting non–national-security information, there is no policy that 

security is required for the links, but satellite service providers and federal 

Satellite system

components Security techniques available Type of threat addressed

TT&C and data links Encryption Cyber attacks

High-power radio frequency (RF) 

uplink

Jamming

Spread spectrum Jamming

Unique digital interface Cyber attacks, jamming

Satellites Hardening Space environment, interceptors, directed-energy weapons

Redundancy Sabotage, space objects, interceptors, directed-energy weapons

Ground stations Physical and logical security 

controls

Physical destruction, sabotage, cyber attacks, jamming, power outages

Hardening Natural occurrences, physical destruction, cyber attacks, jamming

Redundancy Natural occurrences, physical destruction, sabotage, power outages
Page 21 GAO-02-781 Commercial Satellite Security

satellite owners and operators included in our review stated that they 

protect tracking and control uplinks with encryption. However, NSA 

officials stated that not all commercial providers’ tracking and control 

uplinks are encrypted. Concerning the data links, customers are 

responsible for determining whether they are encrypted or not. Most 

commercial satellite systems are designed for “open access,” meaning that 

a transmitted signal is broadcast universally and unprotected. 

A second security technique for links is the use of high-power RF uplinks: 

that is, a large antenna used to send a high-power signal from the ground 

station to the satellite. To intentionally interfere with a satellite’s links, an 

attacker would need a large antenna with a powerful radio transmitter (as 

well as considerable technical knowledge). Two of the commercial 

providers we talked to stated that they use high-power RF uplinks as part 

of their satellite security approach. According to one commercial provider, 

most satellite operators use high-power RF uplinks for TT&C connections 

to block potential unauthorized users’ attempts to interfere with or jam the 

TT&C uplink. 

A third technique for protecting links is the use of spread spectrum 

communication, a technique used by the military and not normally 

implemented by commercial providers. Spread spectrum communication is 

a form of wireless communication in which the frequency of the 

transmitted signal is deliberately varied and spread over a wide frequency 

band. Because the frequency of the transmitted signal is deliberately 

varied, spread spectrum communication can provide security to links 

because it increases the power required to jam the signals even if they are 

detected. Spread spectrum communication is primarily used to optimize 

the efficiency of bandwidth within a frequency range, but it also provides 

security benefits.21

Finally, TT&C links can be protected by the use of a unique digital interface 

between the ground station and the satellite. According to one commercial 

21Two desired outcomes of using spread spectrum communications as a security technique 

are low probability of intercept and low probability of detection, which increase the 

difficulty of detecting and jamming signals. These outcomes, although not mentioned by 

entities in our review, require that the transmission occur in quick, random bursts to make it 

harder to detect, and that the signal is narrowed to make it harder to intercept. In contrast, 

most commercial satellites have a wide beam and continuous coverage, so that as many 

customers as possible can be covered by a limited number of satellites, thus driving up 

return on investment.
Page 22 GAO-02-781 Commercial Satellite Security

satellite service provider, most commercial providers use a unique digital 

interface with each satellite. Tracking and control instructions sent from 

the ground station to the satellite are encoded and formatted in a way that 

is not publicly known. Officials from the commercial satellite vendor stated 

that even if an attacker were successful in hacking one satellite, the unique 

interface could prevent the attacker from taking control of an entire fleet of 

satellites. In addition, communication with the digital interface to the 

tracking and control links requires high transmission power, so that an 

attacker would need a large, powerful antenna. 

Satellites Can Be Protected 

through Hardening and 

Redundancy 

Satellites can be protected by (1) “hardening,” through designs and 

components that are built to be robust enough to withstand harsh space 

environments and deliberate attacks, and (2) the use of redundancy—

backup systems and components. Commercial satellite service providers 

and federal civilian owners and operators told us that they do not harden 

their satellites to the extent that the military does. Commercial providers, 

federal civilian owners and operators, and the military use varying degrees 

of redundancy to protect their satellites. 

As satellites rely increasingly on on-board information processing, 

hardening is becoming more important as a security technique. Hardening 

in this context includes physical hardening and electronic-component 

hardening. Satellites can be hardened against natural environmental 

conditions and deliberate attack, and to ensure survivability.22 Most 

hardening efforts are focused on providing sufficient protection to 

electronic components in satellites so that they can withstand natural 

environmental conditions over the expected lifespan of the satellite, which 

could be nearly 15 years. For hardening against deliberate attacks, some 

techniques proposed include the use of reflective surfaces, shutters, and 

nonabsorbing materials. According to commercial satellite providers, 

commercial satellites are not normally hardened against non-natural 

nuclear radiation because it is too costly. The drawback of hardening is the 

cost and the manufacturing and operational burdens that it imposes on 

satellite manufacturers and providers. 

22Survivability is the property of a system, subsystem, equipment, process, or procedure that 

provides a defined degree of assurance that the named entity will continue to function 

during and after a natural or man-made disturbance, as for example a nuclear burst.
Page 23 GAO-02-781 Commercial Satellite Security

The use of high-quality space parts is another approach to hardening. 

Although all parts used in satellites are designed to withstand natural 

environmental conditions, some very high-quality parts that have 

undergone rigorous testing and have appreciably higher hardness than 

standard space parts are also available, including those referred to as class 

“S” parts. These higher quality space parts cost significantly more than 

regular space parts—partly because of the significant testing procedures 

and more limited number of commercial providers manufacturing 

hardened parts. According to an industry official, high-quality space parts 

are used by the military and are generally not used on commercial 

satellites. 

Commercial satellite providers stated that they also use redundancy to 

ensure availability, through backup satellites and redundant features on 

individual satellites. Backup satellites enable an organization to continue 

operations if a primary satellite fails. One provider stated that it would 

rather spend resources on backup satellites than on hardening future 

satellites or encrypting the TT&C and data links. The provider also 

expressed the view that a greater number of smaller, less costly satellites 

provides greater reliability than is provided by few large satellites, because 

there is more redundancy. According to an industry consulting group, 

backup satellites, which include in-orbit and on-ground satellites, are part 

of commercial satellite providers’ security approaches. When backup 

satellites are used, they are commonly kept in orbit; keeping backup 

satellites on the ground is possible, but it has the disadvantage that the 

system cannot immediately continue operations if the primary satellite 

fails. According to one provider, it could take 4 to 6 months to launch a 

backup satellite stored on the ground. 

In addition, individual satellites can be designed to have redundant parts. 

For example, a commercial satellite provider told us that redundant 

processors, antennas, control systems, transponders, and other equipment 

are frequently used to ensure satellite survivability. Another example is that 

satellites could have two completely separate sets of hardware and two 

paths for software and information; this is referred to as having an A-side 

and a B-side. In general, this technique is not used on commercial satellites, 

according to an industry official. 
Page 24 GAO-02-781 Commercial Satellite Security

Ground Stations Can Be 

Protected Primarily by 

Physical Security Controls 

Techniques to protect ground stations include physical controls as well as 

logical security controls, hardening, and backup ground stations. Ground 

stations are important because they control the satellite and receive and 

process data. One provider stated that providing physical security 

measures to ground stations is important because the greatest security 

threat to satellite systems exists at that location.

Locations of ground stations are usually known and accessible; thus, they 

require physical security controls such as fencing, guards, and internal 

security. One provider emphasized the importance of performing 

background checks on employees. Civilian agencies also stated that they 

protected ground stations through various physical security controls: 

ground stations are fenced, guarded, and secured inside with access 

control devices, such as key cards. 

The commercial satellite service providers included in our review stated 

that they did not protect their ground stations through hardening; this 

technique is primarily used by the military.23 Similarly, most civilian 

agencies we talked to do not harden their ground stations. A ground station 

would be considered hardened if it had protective measures to enable it to 

withstand destructive forces such as explosions, natural disasters, or 

ionizing radiation. 

Commercial satellite providers and federal agency satellite owners and 

operators also may maintain off-line or fully redundant ground stations to 

ensure availability, which can be used if the primary ground station is 

disrupted or destroyed. Off-line backup ground stations may not be staffed 

or managed by the same company, or on a full-time basis. In addition, offline backup ground stations are not necessarily designed for long-term 

control of satellites. On the other hand, one commercial service provider 

stated that it maintained fully redundant, co-primary, geographically 

separated ground stations that are fully staffed with trained operators, 

gated with restricted access, and capable of long-term uninterruptible 

power. In addition, these ground stations periodically alternated which 

satellites they were responsible for as a training exercise. They also 

operated 24 hours a day, 7 days a week, and monitored each other. 

23Hardening of ground stations includes robust physical security features like blast resistant 

physical structures and radomes to protect antennas. 
Page 25 GAO-02-781 Commercial Satellite Security

Federal Satellite Users 

Can Reduce Risks Only 

in Certain Areas, and 

National Policy Is 

Limited

To mitigate the risk associated with using commercial satellites, federal 

agencies focus on areas within their responsibility and control: data links 

and communication ground stations. According to federal agency officials, 

agencies reduce risks associated with using commercial satellites by (1) 

protecting the data’s authentication and confidentiality with encryption, (2) 

securing the data ground stations with physical security controls and 

backup sites, and (3) ensuring service availability through redundancy and 

dedicated services. Federal agencies rely on commercial satellite service 

providers to provide the security techniques for the TT&C links, satellites, 

and satellite control stations. However, federal agency officials stated that 

they were unable to impose specific security requirements on commercial 

satellite service providers. Further, federal policy governing the security of 

satellite systems used by agencies is limited because it addresses only 

those satellites used for national security information, pertains only to 

techniques associated with the links between ground stations and satellites 

and between satellites (cross-links), and does not have an enforcement 

mechanism. Without appropriate governmentwide policy to address the 

security of all satellite components and of non–national-security 

information, federal agencies may not, for information with similar 

sensitivity and criticality, consistently (1) secure data links and 

communication ground stations or (2) use satellites that have certain 

security controls that enhance availability. Recent initiatives by the 

Executive Branch have acknowledged these policy limitations, but we are 

not aware of specific actions to address them.

Agencies Provide 

Encryption to Protect Data

For critical data, agencies primarily use different types of encryption to 

reduce the risk of unauthorized use or changes. For example, the military 

services use encryption to protect most data communicated over 

satellites—either commercially owned or military. DOD officials stated that 

the military services use the strongest encryption algorithms available from 

the NSA for the most sensitive information—national security information. 

For non–national-security information, the military services use less strong 

encryption algorithms, according to DOD officials. The National 

Aeronautics and Space Administration (NASA) also uses NSA-provided 

encryption for critical operations, such as human mission communications 

(that is, for space shuttle missions). Using NSA encryption requires 

encryption and decryption hardware at the data’s source and destination, 

respectively. The use of this hardware requires agencies and satellite 

service providers to apply special physical protection procedures—such as 

restricting access to the equipment and allowing no access by foreign 
Page 26 GAO-02-781 Commercial Satellite Security

nationals. For the next generation of government-owned weather satellites, 

the National Oceanic and Atmospheric Administration (NOAA) and the 

U.S. military plan to use an NSA-approved commercial encryption package 

that will avoid the need for special equipment and allow them to restrict the 

data to authorized users with user IDs and passwords. In addition, NOAA 

will be able to encrypt broadcast weather data over particular regions of 

the world. 

According to NASA and NOAA officials, some agency data do not require 

protection because the risk of unauthorized use or changes is not 

significant or because the information is intended to be available to a broad 

audience. For example, NASA uses satellites to provide large bandwidth to 

transmit scientific data from remote locations. According to NASA 

officials, the agency does not protect the transmission of these data 

because they are considered academic in nature and low risk. In addition, 

the Federal Aviation Administration (FAA) does not encrypt links between 

control centers or between control centers and aircraft, because the data 

on these links go from specific air traffic control centers to specific 

aircraft. According to FAA officials, if the transmissions were required to 

be encrypted, every aircraft would have to acquire costly decryption 

equipment. Further, according to National Weather Service officials, the 

service does not protect the weather data transmitted over commercial 

satellites because the service considers it important to make this 

information widely available not only to its sites but also to government 

agencies, commercial partners, universities, and others with the 

appropriate equipment. 

Agencies Provide Physical 

Security for 

Communications Ground 

Stations

Federal agencies also control the security of the data ground stations that 

send and receive data over satellites. To protect these ground stations, 

federal officials stated that they use physical security techniques, such as 

those discussed earlier. They protect their facilities and equipment from 

unintentional and intentional threats (such as wind, snow, and vandalism). 

For example, according to FAA officials, in certain locations, FAA has 

hardened remote satellite ground stations against high wind and cold 

weather conditions. In addition, NOAA officials stated that many of their 

antennas are hurricane protected. Further, federal officials stated that they 

perform background checks on personnel. NOAA officials stated that they 

perform background checks on satellite technicians to the secret clearance 

level. Federal officials also stated that their ground stations are further 

protected because they are located on large, protected federal facilities. 

For example, military ground stations can be located on protected U.S. or 
Page 27 GAO-02-781 Commercial Satellite Security

allied military bases. Also, National Weather Service officials stated that the 

service’s primary communications uplink is located on a highly secured 

federal site. Further, according to DOD officials, personnel are expected to 

protect the satellite equipment provided to them in the field. Agencies also 

had backup communications sites that were geographically separated, 

including being on different power grids. For example, according to an 

official, the National Weather Service’s planned backup communications 

uplink site will be geographically separated from the primary site and will 

be on a secured federal site. 

Agencies Attempt to Ensure 

Availability through 

Redundancy and Dedicated 

Services 

Federal agencies also reduce the risk associated with using commercial 

satellites by having redundant telecommunications capabilities. For 

example, for the program that provides Alaska’s air traffic control, FAA 

relies on two satellites to provide backup capacity for each other. In 

addition to this redundancy, FAA has requested its commercial satellite 

service provider to preferentially provide services to FAA’s Alaska air 

traffic control system over other customers carried on the same satellites. 

Another FAA program provides primary communications capabilities in 

remote locations and has redundant satellite capacity that can be used if 

the primary satellite fails. The National Weather Service is another 

example. The service uses redundancy to ensure the availability of satellite 

services that broadcast weather data to its 160 locations by contracting for 

priority services that include guarantees of additional transponders or, if 

the satellite fails, of services on other satellites. In addition, the service 

plans to own and operate a backup communications center that is 

geographically separated from the primary site. The service performs 

monthly tests of the backup site’s ability to provide the communications 

uplink to the commercial satellites.

Agencies Do Not Control All 

Aspects of Security and 

Have Limited Ability to 

Influence Availability and 

Security Requirements

Federal agencies rely on the commercial satellite service provider’s 

security techniques for the TT&C links, satellites, and satellite control 

ground stations. Figure 3 graphically depicts the areas not controlled by 

federal agencies. 
Page 28 GAO-02-781 Commercial Satellite Security

Figure 3: Commercial Satellite System Showing Components Not Controlled by Government Agencies

Source: GAO analysis.
Page 29 GAO-02-781 Commercial Satellite Security

To mitigate the risk associated with not controlling aspects of commercial 

satellite security other than protecting the data links and communications 

ground stations, federal agencies attempt to specify availability24 and 

reliability25 requirements, but they acknowledge having had limited 

influence over security techniques employed by commercial satellite 

service providers.26 Federal officials stated that they are usually 

constrained by the availability and reliability levels that can be provided by 

their telecommunications service providers. For example, for one program, 

an FAA contract requires 99.7 percent availability in recognition of the 

satellite service provider’s limitations, though the agency typically receives 

99.8 percent. However, FAA would prefer 99.999 percent availability on this 

program’s satellite communications, which is similar to the reliability level 

being received from terrestrial networks that FAA uses where available. 

According to one FAA official, greater satellite reliability could be gained 

by having multiple satellite service providers furnish communications over 

the same regions, but this approach is too costly. 

Although maintaining established or contracted reliability levels generally 

requires that service providers maintain some level of security, federal 

officials stated that their agencies cannot usually require commercial 

satellite service providers to use specific security techniques. Commercial 

satellite service providers have established operational procedures, 

including security techniques, some of which, according to officials, cannot 

be easily changed. For example, once a satellite is launched, additional 

hardening or encryption of the TT&C link is difficult, if not impossible. 

Some service providers offer the capability to encrypt the command 

uplinks. According to FAA officials, FAA is in the process of performing 

risk assessments, in compliance with its own information systems security 

policies, on the commercial services (including satellite services) that it 

acquires. Based on these risk assessments, FAA officials plan to accredit 

24Availability is the ratio of the total time a service is being used during a given interval to the 

length of the interval. For example, a service provider may state that its services will be 

available 99.99 percent over a year, which amounts to 53 minutes of accumulated outages 

for all causes over the course of the year. Additional decimal places, such as 99.999 percent, 

represent greater levels of availability. Federal Telecommunications Standards Committee, 

Telecom Glossary 2000 (Feb. 2, 2001).

25Reliability is the probability that a service will perform its required function for a specified 

period of time under stated conditions. Federal Telecommunications Standards Committee, 

Telecom Glossary 2000 (Feb. 2, 2001).

26Security is one of many factors that affect satellite availability and reliability. Others 

include weather and power outages. 
Page 30 GAO-02-781 Commercial Satellite Security

and certify the security of the agency’s program that relies on commercial 

satellites.

Existing Federal Policy 

Concerning Commercial 

Satellite Security Is Limited 

Federal policy governing agencies’ actions regarding the security of 

commercial satellite systems is limited, in that it (1) pertains only to 

satellites used for national security purposes, (2) addresses security 

techniques associated with links only, and (3) does not have an 

enforcement mechanism for ensuring compliance. Although the Executive 

Branch has recently acknowledged these policy limitations, we are not 

aware of specific actions to address them.

NSTISSP No. 12, the current policy governing satellite system security, 

applies only to U.S. space systems (U.S. government-owned or 

commercially owned and operated space systems) that are used for 

national security information and to imagery satellites that are or could be 

used for national security purposes during periods of conflict or war. It 

does not apply to systems that process sensitive, non–national-security 

information. Issued by the National Security Telecommunications and 

Information Systems Security Committee (now the Committee on National 

Security Systems (CNSS)), NSTISSP No. 12 has as its primary objective “to 

ensure that information assurance is factored into the planning, design, 

launch, sustained operation, and deactivation of U.S. space systems used to 

collect, generate, process, store, display, or transmit/receive national 

security information, as well as any supporting or related national security 

systems.” NSTISSP No. 12 also suggests that federal agencies may want to 

consider applying the policy’s information assurance requirements to those 

space systems that are essential to the conduct of agencies’ unclassified 

missions, or to the operation and maintenance of critical infrastructures.

In addition to having a focus only on national security, the policy is further 

limited in that it addresses security techniques only for the links. It does 

not include physical security requirements for the satellites or ground 

stations. Specifically, for satellite systems to which it applies, NSTISSP No. 

12 states that approved U.S. cryptographies shall be used to provide 

confidentiality for the (1) command and control uplinks, (2) data links that 

transmit national security information between the ground and the space 

platforms, (3) cross-links between space platforms, and (4) downlinks from 

space platforms to mission ground or processing centers. 

Also, there is no enforcement mechanism to ensure agency compliance 

with the policy. According to one NSA official on the CNSS support staff, 
Page 31 GAO-02-781 Commercial Satellite Security

enforcement of such policies has always been a problem, because no one 

has the authority to force agencies’ compliance with them. According to 

some agency officials, agencies typically do not test their service providers’

implementation of security procedures. 

According to the federal and commercial officials involved in our study, no 

commercial satellite is currently fully compliant with NSTISSP No. 12, and 

gaining support to build compliant systems would be difficult. According to 

commercial satellite industry officials, there is no business case for 

voluntarily following the NSTISSP No. 12 requirements and implementing 

them in the satellites and ground stations, including networks that are 

currently being developed. 

Commercial satellite service providers also raised concerns about the 

impact of NSTISSP No. 12 on their future commercial satellite systems. 

Several officials stated that if compliance were required, it would 

significantly increase the complexity of managing the satellites, because 

encryption key management is cumbersome,27 and appropriately 

controlling access to the hardware is difficult in global companies that have 

many foreign nationals. Also, commercial satellite service providers stated 

that encrypting the TT&C links could increase the difficulty of 

troubleshooting, for example, because the time it takes to encrypt and then 

decrypt a command could become significant when a TT&C problem 

arises. Other issues raised that make NSTISSP No. 12 difficult to implement 

include the following:

• Some satellite service providers view compliance with it as not 

necessary for selling services to the government, since in the past 

agencies have used satellites that did not comply with prior security 

policy. For example, DOD has contracted for services on satellites that 

were not compliant with the previous and existing policy for various 

reasons. However, at times, noncompliant satellites have been DOD’s 

only option.

• Commercial clients will likely be unwilling to pay the additional cost 

associated with higher levels of encryption. Significant costs would 

include licensing agreements and redesigning hardware for new 

encryption technologies. 

27A key is a special value associated with an encryption algorithm that is used for coding and 

decoding.
Page 32 GAO-02-781 Commercial Satellite Security

• Satellite industry officials stated that their experience shows that 

encryption does not really provide much greater security than other 

techniques that protect TT&C and data links. 

Notwithstanding the above issues, in response to the policy’s limitations,

DOD officials from the Office of the Assistant Secretary of Defense for 

Command, Control, Communications, and Intelligence stated that the 

department had started drafting a policy that would require all commercial 

satellite systems used by DOD to meet NSTISSP No. 12 requirements. This 

draft policy includes a waiver process requiring prior approval before any 

satellite system could be used that did not meet the security requirements. 

If approved, this policy would apply only to DOD. DOD officials are 

anticipating that this policy will be approved by the end of 2002. 

In addition to DOD’s efforts, a CNSS official stated that a draft policy was 

developed to address the lack of national policy or guidance for the 

assurance of non–national-security information. Although this policy was 

broad in scope, covering many aspects of information assurance, this 

official stated that satellite security could be included in its scope. 

However, this official also stated that the CNSS’s efforts ended in April 2002 

when it sent the draft policy to the Director of the Office of Management 

and Budget (OMB) for consideration, because the CNSS lacks authority in 

the area of non–national-security information. In transmitting the draft 

policy to the Director, OMB, the CNSS Chair encouraged the development 

of this policy as a first step in establishing a national policy addressing the 

protection of information technology systems that process sensitive 

homeland security information, as well as information associated with the 

operation of critical infrastructures. According to an OMB official, the draft 

policy is valuable input for future policy decisions related to protecting 

government information.

Recognizing that space activities are indispensable to our national security 

and economic vitality, on May 8, 2002, the President’s National Security 

Advisor sent a memorandum to top cabinet officials stating that she plans 

to recommend that the White House initiate a review of U.S. space policies 

that have been in place since 1996. To date, we are not aware of specific 

actions taken in response to the draft policy sent to OMB and the National 

Security Advisor’s memorandum. 

Without appropriate governmentwide policy to address the security of all 

satellite components and of non–national-security information, federal 

agencies may not, for information with similar sensitivity and criticality, 
Page 33 GAO-02-781 Commercial Satellite Security

consistently (1) secure data links and communication ground stations or 

(2) use satellites that have certain security controls that enhance 

availability. As a result, federal agencies risk losing needed capabilities in 

the event of the exploitation of satellite system vulnerabilities.

National CIP Initiatives 

Addressing Satellite 

Security Have Been 

Limited

PDD 63 was issued to improve the federal approach to protecting our 

nation’s critical infrastructures by establishing partnerships between 

private-sector entities and the federal government. Although this directive 

addressed the satellite vulnerabilities of GPS and led to a detailed 

vulnerability assessment, the satellite industry has not received focused 

attention as part of this national effort. Given the importance of 

commercial satellites to our nation’s economy, the federal government’s 

growing reliance on them, and the dependency of many other 

infrastructures on satellites, not including them in our national CIP 

approach creates the risk that these critical components of our information 

and communication infrastructure may not receive needed attention.

Both PDD 63 and the report of the President’s Commission on Critical 

Infrastructure Protection (October 1997) addressed satellite vulnerabilities 

of the GPS and made several recommendations to the Secretary of 

Transportation, including to fully evaluate these vulnerabilities and actual 

and potential sources of interference to the system. In August 2001, the 

John A. Volpe Transportation Systems Center issued a report that includes 

an assessment of the vulnerabilities of the GPS; analysis of civilian aviation, 

maritime, and surface uses; assessment of the ways that users may be 

affected by short- or long-term GPS outages; and recommendations to 

minimize the safety and operational impacts of such outages.28 One 

overarching finding was that because of the increasing reliance of 

transportation on GPS, the consequences of loss of the signal could be 

severe in terms of safety and of environmental and economic damage to the 

nation. 

Despite the focused attention on GPS, other aspects of the satellite 

industry have not received national attention. In PDD 63, commercial 

satellites were not identified as a critical infrastructure (or as part of one), 

and thus are not specifically included as part of our nation’s approach to 

28John A. Volpe National Transportation Systems Center, Vulnerability Assessment of the 

Transportation Infrastructure Relying on the Global Positioning System: Final Report

(Aug. 29, 2001). 
Page 34 GAO-02-781 Commercial Satellite Security

protecting critical infrastructures. Further, PDD 63 does not explicitly 

include the commercial satellite industry as part of the information and 

communications infrastructure sector, nor does the newly issued national 

strategy for homeland security. Although there have been discussions 

about expanding the coverage of individual sectors (particularly since the 

events of September 11, 2001), National Telecommunications and 

Information Administration (NTIA) officials stated that there are no 

specific plans to build better partnerships with satellite builders and 

operators as part of their efforts. CIAO officials also told us that there are 

no specific plans to include commercial satellite companies in current 

national efforts. However, CIAO added that some of the current 

infrastructure sectors may address satellites in their plans for industry 

vulnerability assessments and remediation, since some of these 

infrastructures rely on satellites for communications or other functions, 

such as tracking shipments or trucks, or monitoring the condition of 

equipment. The telecommunications ISAC reiterated NTIA’s and CIAO’s 

comments that there are no specific plans to include satellites in national 

CIP efforts. The ISAC for the telecommunications sector, recognized by the 

President’s National Security Council in January 2000, is the National 

Coordinating Center for Telecommunications (NCC), which is operated by 

the National Communications System. As such, NCC is responsible for 

facilitating the exchange of information among government and industry 

participants regarding computer-based vulnerability, threat, and intrusion 

information affecting the telecommunications infrastructure. Also, the 

center analyzes data received from telecommunications industry members, 

government, and other sources to avoid or lessen the impact of a crisis 

affecting the telecommunications infrastructure. Since its recognition as an 

ISAC, NCC membership has expanded beyond traditional 

telecommunications entities to include some aerospace companies such as 

Boeing and Raytheon, but the ISAC does not specifically focus on 

commercial satellites. 
Page 35 GAO-02-781 Commercial Satellite Security

Officials from one of the satellite service providers told us that they would 

endorse an ISAC-like forum to discuss vulnerabilities to commercial and 

military satellites. In July 2002, we recommended that when developing the 

strategy to guide federal CIP efforts, the Assistant to the President for 

National Security Affairs, the Assistant to the President for Homeland 

Security, and the Special Advisor to the President for Cyberspace Security 

ensure, among other things, that the strategy includes all relevant sectors 

and defines the key federal agencies’ roles and responsibilities associated 

with each of these sectors.29 Given the importance of satellites to the 

national economy, the federal government’s growing reliance on them, and 

the many threats that face them, failure to explicitly include satellites in the 

national approach to CIP leaves a critical aspect of the national 

infrastructure without focused attention. 

Conclusions Commercial satellite service providers use a combination of techniques to 

protect their systems from unauthorized use and disruption, including 

hardware on satellites, physical and logical controls at ground stations, and 

encryption of the links. Although this level of protection may be adequate 

for many government requirements, commercial satellite systems lack the 

security features used in national security satellites for protection against 

deliberate disruption and exploitation. 

Federal agencies reduce the risk associated with their use of commercial 

satellites by controlling the satellite components within their 

responsibility—primarily the data links and communication ground 

stations. But the satellite service provider is typically responsible for most 

components—the satellite, TT&C links, and the satellite control ground 

stations. Because federal agencies rely on commercial satellite service 

providers for most security features, they also reduce their risk by having 

redundant capabilities in place. However, national satellite protection 

policy is limited because it pertains only to satellite systems that are used 

for national security information, addresses only techniques associated 

with the links, and does not have an enforcement mechanism. Recent 

initiatives by the Executive Branch have acknowledged these policy 

limitations, but we are not aware of specific actions taken to address them. 

29U.S. General Accounting Office, Critical Infrastructure Protection: Federal Efforts 

Require a More Coordinated and Comprehensive Approach to Address Information 

Attacks, GAO-02-474 (Washington, D.C.: July 15, 2002).
Page 36 GAO-02-781 Commercial Satellite Security

Satellites are not specifically identified as part of our nation’s critical 

infrastructure protection approach, which relies heavily on public-private 

partnerships to secure our critical infrastructures. As a result, a national 

forum to gather and share information about industrywide vulnerabilities 

of the satellite industry does not exist, leaving a national critical 

infrastructure without focused attention. 

Recommendations We recommend that in pursuing the draft policy submitted to OMB for 

completion and the recommended review of U.S. space policies, the 

Director of OMB and the Assistant to the President for National Security 

Affairs review the scope and enforcement of existing security-related space 

policy and promote the appropriate revisions of existing policies and the 

development of new policies to ensure that federal agencies appropriately 

address the concerns involved with the use of commercial satellites, 

including the sensitivity of information, security techniques, and 

enforcement mechanisms. 

Considering the importance of satellites to our national economy, the 

government’s growing reliance on them, and the threats that face them, we 

recommend that the Assistant to the President for National Security 

Affairs, the Assistant to the President for Homeland Security, and the 

Special Advisor to the President for Cyberspace Security consider 

recognizing the satellite industry as either a new infrastructure or part of an 

existing infrastructure. 

Agency Comments and 

Our Evaluation

We received written comments on a draft of this report from the Deputy 

Assistant Secretary of Defense, Command, Control, Communications, 

Intelligence, Surveillance, and Reconnaissance (Space and Information 

Technology Programs), Department of Defense; the Chief of the Satellite 

Communications and Support Division, United States Space Command, 

Department of Defense; the Chief Financial Officer/Chief Administrative 

Officer, National Oceanic and Atmospheric Administration, Department of 

Commerce; and the Associate Deputy Administrator for Institutions, 

National Aeronautics and Space Administration. The Departments of 

Defense and Commerce and the National Aeronautics and Space 

Administration concurred with our findings and recommendations (see 

apps. II, III, and IV, respectively) and provided technical comments that 

have been incorporated in the report, as appropriate (some of these 

technical comments are reproduced in the appendixes). 
Page 37 GAO-02-781 Commercial Satellite Security

We also received technical oral comments from officials from the Critical 

Infrastructure Assurance Office, Department of Commerce; Federal 

Aviation Administration, Department of Transportation; Office of 

Management and Budget; and United States Secret Service, Department of 

Treasury; in addition, we received written and oral technical comments 

from five participating private-sector entities. Comments from all these 

organizations have been incorporated into the report, as appropriate. We 

did not receive comments from the Special Advisor to the President for 

Cyberspace Security.

As we agreed with your staff, unless you publicly announce the contents of 

this report earlier, we plan no further distribution of it until 30 days from 

the date of this letter. At that time, we will send copies of this report to 

other interested congressional committees and the heads of the agencies 

discussed in this report, as well as the private-sector participants. The 

report will also be available on GAO’s website at www.gao.gov. 

If you have any questions about matters discussed in this report, please 

contact me at (202) 512-3317 or contact Dave Powner, Assistant Director, at 

(303) 572-7316. We can also be reached by E-mail at daceyr@gao.gov and 

pownerd@gao.gov, respectively. Contributors to this report include 

Barbara Collier, Michael Gilmore, Rahul Gupta, Kevin Secrest, Karl Seifert, 

Hai Tran, and Jim Weidner.

Sincerely yours, 

Robert F. Dacey

Director, Information Security Issues
Page 38 GAO-02-781 Commercial Satellite Security

Appendix I

Objectives, Scope, and Methodology ApApenednxidexiIs

Our objectives were to determine (1) what security techniques are 

available to protect satellite systems from unauthorized use, disruption, or 

damage; (2) how federal agencies reduce the risks associated with their use 

of commercial satellite systems; and (3) what federal critical infrastructure 

protection efforts are being undertaken to address satellite system security 

through improved government/private-sector cooperation. To accomplish 

these objectives, we reviewed technical documents, policy documents, and 

directives, and we interviewed pertinent officials from federal agencies and 

the private sector involved in manufacturing and operating satellites and 

providing satellite services.

To determine what security techniques are available to protect satellite 

systems from unauthorized use, disruption, or damage, we reviewed 

technical documents and policy, such as NSTISSP No. 12 and various other 

sources, and we interviewed pertinent federal officials from the 

Department of Defense (DOD); the Federal Aviation Administration (FAA); 

the National Aeronautics and Space Administration (NASA), including the 

Goddard and Marshall Space Flight Centers; the National Oceanic and 

Atmospheric Administration (NOAA); the National Security Agency (NSA); 

and the Department of Treasury’s United States Secret Service. The DOD 

organizations whose documentation we reviewed and whose officials we 

interviewed included the Air Force; the Army; the Assistant Secretary of 

Defense for Command, Control, Communications, and Intelligence; the 

Cheyenne Mountain Air Force Station; the Defense Information Systems 

Agency; the National Security Space Architect; the Navy; and the U.S. 

Space Command. In addition, we reviewed documentation and interviewed 

officials from private-sector organizations that manufacture and operate 

satellite systems, including Intelsat, Lockheed Martin, Loral Space & 

Communications, Ltd. (Loral Skynet and Loral Space Systems groups), 

Northrop Grumman TASC, the Satellite Industry Association, and W.L. 

Pritchard & Co., L.C. We identified these organizations through relevant 

literature searches, discussions with organizations, and discussions with 

GAO personnel familiar with the satellite industry. We did not develop an 

all-inclusive list of security techniques, but we attempted to establish the 

most commonly used of the security techniques available.

To determine how federal agencies reduce the risks associated with their 

use of commercial satellite systems, we identified and reviewed relevant 

federal policy, including National Security Telecommunications and 

Information Systems Security Committee policies and applicable federal 

agency policies, such as the FAA’s Information Systems Security Program 

Handbook. We also reviewed documentation and interviewed federal 
Appendix I

Objectives, Scope, and Methodology

Page 39 GAO-02-781 Commercial Satellite Security

officials from DOD, FAA, NASA, NSA, and NOAA. In addition, in meetings 

with commercial service providers holding government contracts, we 

discussed any special requirements placed on commercial service 

providers by federal agencies.

To determine what federal critical infrastructure protection (CIP) efforts 

were being undertaken to address satellite system security, we reviewed 

various orders, directives, and policies, such as Executive Order 13231 and 

PDD 63. In addition, we interviewed pertinent federal officials from the 

Critical Infrastructure Assurance Office, National Communications 

System/National Coordinating Center for Telecommunications, and 

National Telecommunications and Information Administration. Further, in 

interviews with commercial service providers, we discussed their 

involvement in national CIP-related activities. 

We performed our work in Washington, D.C.; Bedminster, New Jersey; 

Colorado Springs, Colorado; and Palo Alto, California, from December 2001 

through June 2002, in accordance with generally accepted government 

auditing standards. We did not evaluate the effectiveness of security 

techniques being used by federal agencies and the private sector, or of the 

techniques used by federal agencies to reduce the risks associated with 

their use of commercial satellite systems.
Page 40 GAO-02-781 Commercial Satellite Security

Appendix II

Comments from the Department of Defense ApendxiI
Appendix II

Comments from the Department of Defense

Page 41 GAO-02-781 Commercial Satellite Security
Page 42 GAO-02-781 Commercial Satellite Security

Appendix III

Comments from the Department of 

Commerce ApendxiI
Appendix III

Comments from the Department of 

Commerce

Page 43 GAO-02-781 Commercial Satellite Security
Appendix III

Comments from the Department of 

Commerce

Page 44 GAO-02-781 Commercial Satellite Security

Now on p. 6.

Now on p. 26.

Now on p. 27.
Page 45 GAO-02-781 Commercial Satellite Security

Appendix IV

Comments from the National Aeronautics and 

Space Administration ApendxiIV

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