8-1 Threats to U.S. Space Systems and Countermeasures
a. Space threats and countermeasures must be examined from two different perspectives.
  • Threats to U.S. space systems and countermeasures.
  • Threats to U.S. military forces from foreign space systems and countermeasures.
Space Segments b. Space systems are critical to U.S. military forces in all types of operations and at all levels of conflict. Space systems generally consist of three segments:
  • User segment
  • Control segment
  • Space segment
The threats to each of these segments is different, therefore each will be discussed separately.
User Segment c. The user segment consists of ground, aircraft and ship terminals and user sets.
User Segment Threats d. The threats to the systems that comprise the user segment systems are generally the same as the threats to other systems operated by the owning unit. They are exposed to the same threats as other equipment in the area because they can be damaged or destroyed by direct fire, indirect fire, ground attack or air attack. Ground terminals, such as small UHF transceivers and GPS receivers, have very small visual signatures. It is unlikely that these small terminals would be targeted directly. Some larger components of user segment equipment and terminals, particularly large satellite antennas, have distinct visual signatures which should be camouflaged or positioned to make detection by an enemy more difficult. Satellite receivers do not emit any identifiable electromagnetic signature. Most transmitters which send signals to satellites use directional antennas so that output power is focused on the satellite. This makes detection by ground and even aircraft electronic warfare equipment more difficult unless the transmitting antenna is pointed at a low angle to the horizon and in the direction of the enemy or the enemy detection system is close enough to detect a side lobe emitted by the antenna.
User Segment Counter- measures e. The countermeasures to protect the user segment of a space system are no different than the countermeasures to protect other similar type equipment.
  • Minimize exposure of equipment to direct or indirect fire through terrain selection and ballistic protection.
  • Minimize detection of transmissions through proper antenna siting and orientation.
  • Camouflage large items or equipment with distinctive signatures
Control Segment f. The control segment consists of facilities associated with telemetry, tracking and commanding (TT&C) of satellites and the network control of users accessing the satellite(s) such as mission control stations, tracking stations, monitoring facilities and facilities designed to communicate commands to the satellite(s). These facilities are critical to the continued operation of a satellite. In general, these are specialized facilities. Many of the facilities are located outside the United States. They are often in remote areas which can make physical security of the site difficult. In some respects these facilities represent the most vulnerable segment of most space systems.
8-1 Threats to U.S. Space Systems and Countermeasures, cont'd
Control Segment Threats g. Most control segment facilities are susceptible to being damaged or destroyed by enemy ground or air attack.
Control Segment Counter- measures h. Most mission control facilities for U.S. space systems are located in CONUS. An attack by a foreign military force would probably be considered as a strategic threat against the United States and would result in escalation of the level of conflict. Protection against terrorist attack can be accomplished by a reinforced guard force and increased security measures. Protection of control facilities located overseas is coordinated with the host nation.
Control Stations i. Survivability of control stations can be increased by increasing their mobility thus making targeting by an enemy more difficult. Mobility can be achieved by making the stations smaller and lighter. Control stations located in a combat theater of operations are more susceptible to enemy attack than those located in more secure areas away from the combat zone. Positioning of control segment terminals is determined by the type of system and the orbit of the satellites being controlled. In general, satellites in high altitude orbits, particularly in geostationary orbit, require less control than those in low Earth orbit. In addition, the footprint of a satellite in geostationary orbit is usually much greater than one in low Earth orbit, therefore the control station could be a great distance from the user terminals. For example, during DESERT STORM, DSCS user terminals in the Kuwait theater were provided network control by a control station in Germany. The GPS satellites require precisely located and aligned monitoring stations. The current system has five fixed monitoring stations around the world. The destruction of one of these would result in some GPS satellites being out of contact with the Master Control Station in Colorado for extended periods. A mobile monitoring station would be able to be deployed to replace any of the fixed monitoring stations, if necessary. Most satellite terminals used by U.S. tactical military forces are already mobile but some could be made smaller which would enhance their mobility. Mobile terminals also have the advantage that they can be repositioned when the tactical forces they are supporting move. In many cases, however, the antennas must be dismantled and reassembled in the new location thus communication with the satellite or the reception of data from the satellite is not possible while moving. Most space systems have provisions for another facility to take over mission control should the primary facility not be able function.
Space Segment j. The space segment consists of satellites orbiting the Earth. Satellites are not invulnerable to incapacitation, damage or destruction but they are the least vulnerable segment of most space systems. The satellites are small targets, travelling at high speed. Nothing is invulnerable and space systems are not an exception. The primary threat to all operational satellites is the environment in space. It is also possible for a nation to develop systems capable of damaging or destroying an orbiting spacecraft. Deliberately negating a satellite is not a simple task. Few nations have the capability to interfere with a satellite. Only the United States and the Soviet Union have ever demonstrated the ability to destroy an orbiting satellite. Of course, if an enemy is willing to expend enough time, money, materiel and other resources, any system can be disrupted, damaged or destroyed.
Threat from the Space Environment k. The environment in space looks peaceful but it is not benign. As explained in Chapter 5, space is a hostile environment that is much different than on the surface of the Earth. In spite of the fact that satellites are designed to operate in space, more satellites have failed due to the effects of the environment than any other cause.
Atmospheric Drag Hazard l. Atmospheric drag is a hazard for LEO satellites. Although the density of the atmosphere above 100 miles is very low, satellites at this altitude must travel at about 17,000 mph. There are enough molecules of atmospheric gasses at 100 miles altitude to induce low levels of drag. The more paraphernalia (especially solar arrays) protruding from the basic satellite, the higher the overall drag. Drag results in a decrease in orbital velocity. As the satellite slows, it drops in altitude, where drag is even greater. Unless its orbit is raised, the satellite will eventually enter even more dense atmosphere and will burn up. Above LEO, the atmosphere is not a threat because the satellite's life is shorter than the time it will take for the orbit to decay. High levels of solar activity cause the atmosphere to expand outward. This can result is a significant shortening of orbital lifetime.
Solar Energy m. Solar energy in the form of both light and flows of atomic particles combine to influence the orbits of satellites. Their net effect is the same as atmospheric drag, resulting in accelerating the decay of the orbit. The amount of energy varies with the activity of the Sun; periods of large prominences and sun spots can greatly increase the perturbation of orbits. The same rules apply; more surface area on the satellite translates into higher drag.
High Energy Radiation n. High energy radiation and charged particles from the Sun and from outside the solar system can damage microcircuits on satellites. The Earth's magnetic field deflects some types of radiation and charged particles but there are others upon which a magnetic field has little effect. The intensity of the radiation is greater when the Sun is more active. All satellites are designed to withstand normal radiation levels or they would fail soon after achieving orbit. Average radiation levels in space are higher than on the surface of the Earth. There are regions within the Van Allen radiation belts surrounding the Earth where the concentration of charged particles is much higher than average. The result is that most satellites have more hardening than ground systems.
Thermal Environment o. The thermal environment in space is also hazardous. Parts of satellites in shadow can radiate heat into space until the temperature is near absolute zero (absolute zero = 0º Kelvin = 273º C = 460º F). Parts exposed to direct sunlight can rapidly heat to high temperatures. The performance of some components changes significantly over a range of temperatures. Electronic components can completely fail if the temperature gets too high. Any failures associated with these thermal management systems may mean failure of the satellite.
Outgassing p. Outgassing is a problem associated with operating in the high vacuum (referred to as a hard vacuum) found at LEO. Outgassing is the boiling off, albeit at a low rate, of volatile particles from the materials in the satellite. Some of these materials, when subjected to a hard vacuum, lose part of their mass to sublimation; that is, some molecules evaporate slowly into the vacuum of space directly from the solid phase to the gaseous phase. Examples of these materials include many microelectronic chips and integrated circuits, circuit boards, some plastics, lubricants, insulation and molded composite materials. Materials that use solvents and adhesives to bind parts together have residual volatile components of solvents and adhesives in the finished products. Outgassing may result in deposits of thin films of outgassed materials on other surfaces on or in the satellite. Should outgassing deposit material on sensors or certain electronics, sensor degradation and even satellite failure can result. Over time, outgassing can cause physical changes to the properties of some materials.
Space Debris q. Space debris is a significant and growing hazard to satellites. Space debris is manmade, nonoperational material in orbit around the Earth. Space debris ranges in size from very small paint chips to complete rocket boosters. A number of rocket bodies and even satellites have exploded after achieving orbit, thus adding to the space debris problem. Below about 150 miles in altitude, most space debris is slowed by atmospheric drag, falls into more dense atmosphere and burns up. Impacting at thousands of miles an hour, even the smallest of these items can cause disproportionate damage. The U.S. Space Shuttle Challenger suffered window damage from a .2mm fleck of white paint that impacted at 8,000 mph. The Long Duration Exposure Facility<$ISatellites;Long Duration Exposure Facility (LDEF)>, a satellite left in orbit for six years before being recovered, showed marked damage from thousands of collisions.
Counter measures to the Space Environment r. There is no way to change the environment in space therefore satellites must be designed to survive the hostile environment of space. Since the late 1950's much has been learned about conditions in space. Technology has developed materials that are much more resistant to damage. Reliable thrusters with sufficient fuel provide thrust to raise a satellite's orbit to counter the effects of atmospheric and solar drag. Electronics are built to be resistant to many forms of radiation. Thermal management systems provide heat where needed, reflect sunlight and dissipate concentrations of heat that build up in the satellite into space. Satellites such as DoD's DMSP weather satellite and others carry sensors to characterize the environment in space. Shields protect critical components from micrometeorites and small pieces of space debris. Today most satellite failures occur during launch or shortly after being placed into orbit due to the mechanical or electronic failure of some component. If they continue to operate after this initial period, they remain operation for many years unless designed for a shorter operating life.
8-2 Threat from Deliberate Attack
Introduction a. A deliberate attack of a satellite can consist of jamming of signals to the spacecraft, spoofing, or the use of a weapon to damage or destroy the satellite.
Jamming b. Satellites routinely receive commands from the control segment that cause the satellite to change its operation. This may involve commands to reposition the satellite in its orbit, to adjust power levels, to control the thermal management subsystem. In addition, the control segment sends signals to the satellite to adjust the operation of the payload. For example, GPS navigation messages transmitted by the payload are routinely updated. Communications satellites receive signals transmitted by users, route them through the communications payload processor on the satellite and retransmit the signal to other users. Jamming of a satellite involves transmitting signals which interfere with the operation of the satellite or its payload.
Susceptibility c. Susceptibility of a satellite is determined by many factors to include the frequency of the signals, the directionality of the receiving antennas, the power of the jamming signal compared to the user's signals, the codes required to access the satellite, and other factors.
UHF vs. SHF d. In general, UHF communications satellites are more susceptible to jamming than SHF communications satellites because the UHF signal has a narrower bandwidth and the receiving antenna is designed to receive signals from a large geographic area. SHF communications satellites are more susceptible than EHF communications satellites.
8-3 Anti-Satellite (ASAT) Weapons
Anti-Satellite (ASAT) Weapons a. An antisatellite weapon is intended to physically damage or destroy a target satellite. There have been a variety of antisatellite weapons concepts and designs. Some have even been built and tested. Direct Ascent, coorbital, and "mines." Warheads of varying types have been demonstrated or postulated, from nuclear to simple sand and even lightweight plastic balloons.
Direct Ascent ASAT Weapon b. Direct ascent ASAT weapons launch directly at the satellite, intercepting it as it approaches overhead, in much the same way that an air defense missile intercepts an aircraft. There is no attempt to place the ASAT weapon into orbit. A typical direct ascent ASAT attacks the target satellite nearly head on, resulting in closing velocities on the order of 16 kilometers per second. This is similar to hitting a bullet with a bullet. Accurate tracking of the target satellite is essential and the U.S. has the best and most comprehensive satellite tracking network in the world. The seeker and processor on the ASAT weapon must be capable of identifying the target and locking on it. U.S. technology improvements have demonstrated the ability to intercept a satellite as it passes nearly overhead. At impact velocities as high as 16 km per second, no explosive is needed when the ASAT strikes the satellite. The kinetic energy involved destroys the satellite. To date, only the U.S. has successfully demonstrated a direct ascent ASAT attack. Direct ascent ASAT weapons are restricted to engaging only satellites in low Earth orbit.
Co-orbital ASAT Weapon c. A coorbital ASAT weapon<$IAntiSatellite Weapons> is launched into an orbit similar to the target satellite, closes in on the target, then destroys it, usually with a warhead exploded at short range. The USSR developed a coorbital ASAT weapon and tested it about 20 times with less than half the texts being successful. The ASAT payload was launched on an S11 Tsyklon rocket. The maximum demonstrated operational altitude was 2000 kilometers. This type of ASAT has a limited amount of maneuverability, and is expected to achieve the kill on the second orbit. The last operational test was conducted in 1982.
Space Mines d. Space mines have not been deployed, however the concept is simple. A satellite with one or more explosive charges is launched into space and placed into GEO close (1,000 km) to the target satellite, then placed into a storage mode, perhaps for years, until called upon to make the attack. At that time the mine is awakened by ground control, "drifted" over to the target satellite, and commanded to destroy the target. To deploy a space mine, a country requires the ability to build the satellite, launch it into GEO and to control it from the ground. With the ability to track small objects in space it is unlikely that a space mine could be deployed without being detected.
8-4 Other Threats From Deliberate Attack
Lasers a. Lasers generate intense beams of light. A characteristic of lasers is that the light in the beam is coherent, i.e., the light waves are aligned. The beam does not radiate in all directions, thus beam divergence is a small angle. The result is that a high percentage of the energy radiate out of the end of the laser can be focused on a target a considerable distance away. Laser weapons damage or destroy their target by heating them. Generating the intense laser beam, controlling the output, tracking a fast moving satellite and keeping the beam focused on the satellite are difficult tasks. No known operational ASAT lasers are deployed but there are working prototypes which have engaged ground targets. There is no evidence that a laser weapon has ever been used to destroy an onorbit satellite.
Particle Beam b. Particle beam weapons (either charged particle beams or neutral particle beams) accelerate atomic particles (neutrons, protons, or electrons) to relativistic velocities (significant fractions of the speed of light) toward their targets. Depending on beam type, intensity, and dwell time, the results of this beam attack can vary from cutting metal to overloading internal electronics. Both ground based and spacebased systems have been proposed. A few ground based prototypes have been demonstrated but no operational particle beam weapons are currently deployed by any nation. Testing of such a system to insure that it is operational would be essential and such test would probably be detectable.
Microwave and other Radio Frequency (RF) Attack c. Like lasers, microwave and other RF weapons are also speedoflight weapons. Like particle beam weapons, there are no known RF ASAT weapons deployed today. However, the likelihood is that eventually weapons of this type will be acquired, most likely as both groundbased and spacebased systems with sufficient flexibility to allow multiple attacks within a short period of time. The RF weapon principle is to cause a meltdown in the internal communications architectures of the targeted satellites.
Deliberate Attack Counter- measures d. Space systems are not defenseless. There are many countermeasures which can be used to reduce or eliminate threats and enhance the survivability of satellites.
Treaties and Agreements e. Treaties and agreements between nations are useful as strategic countermeasures to provide protection and survivability. For example, one of the provisions of the 1967 Outer Space Treaty, ratified by the space nations of the world, states that nations will not interfere with another nation's space systems. This agreement serves a useful purpose because it clarifies that any action against another nation's space system is an act of aggression rather than just nuisance interference. Jamming of radio broadcasts from ground transmitters is not in violation of any treaty. Jamming of control communications to or from a satellite would, however, be considered a violation of the Outer Space Treaty. Treaties and agreements are most effective when they are of some benefit to all the signatories. To be effective, there must be means to verify compliance with the provisions of the treaty or agreement. Once hostilities begin, treaties and agreements between combatants may have little relevance.
Deterrence f. Deterrence has been an effective strategic countermeasure in many different areas to include space systems. Deterrence involves informing adversaries, in advance, that if actions are taken against friendly space systems, then corresponding retaliatory action will be taken. Deterrence presumes that the U.S. has the political fortitude and means to damage, destroy or otherwise negate the enemy's space systems and the enemy values it's space systems. Effective deterrence presumes a relative parity or balance between potential opponents. Satellites must include special sensors to detect and confirm that a failure was the direct result of a deliberate enemy action against the satellite rather than an act of nature or a routine failure of a component. In addition, an enemy must believe that potential losses exceed possible gains. Measuring the success of deterrence is as difficult as measuring as the impact of a safety program. If nothing happens, there is nothing to measure.
8-4 Other Threats From Deliberate Attack, cont'd
Proliferation g. Proliferation results in a more robust system that gives an enemy too many targets to damage or destroy before there is a significant impact on the effectiveness of a system. An attacker has to expend more resources before there is any effective degradation of an enemy's system. Proliferation can result from the inherent design of a system so that if some components are damaged, destroyed or simply fail to operate correctly the overall system retains its operational effectiveness. For example, the Global Positioning System consists of 21 satellites and 3 operational, on orbit spares. The system is designed so that the loss of a satellite has only minor impact on the overall operational effectiveness of the system. The loss of even more GPS satellites would result in a gradual degradation of capabilities rather than a catastrophic failure. For this reason, a surprise attack that could destroy the system would be extremely difficult and the likelihood of detection of preparations of such a large effort would be high. Most satellites are expensive, therefore building, launching and maintaining extra satellites merely to have excess capability is rarely an affordable option. Proliferation can also be the result of widespread distribution of components, especially user terminals. For example, it would be extremely difficult for an enemy to physically destroy enough UHF SATCOM user terminals in a large force to have a significant impact on military operations. Not only are the terminals relatively small, but there are thousands of them.
Deception h. Deception makes it more difficult for an enemy to detect, track and engage the real components of a system. Camouflage of user terminals and ground control terminals to conceal them is a common deception technique. Positioning terminals where they would not be expected or where the surrounding environment make them more difficult to detect can be effective ways to improve survivability. Physical and electronic decoys, especially of larger terminals, can be an effective method in deceiving an enemy as to the location and number of the actual terminals. Deception techniques and plans are, by their nature, usually classified.
Orbit Selection i. The orbit selected for a satellite is based primarily on the mission it is designed to perform. The orbit also influences the satellite's vulnerability. A satellite in low Earth orbit travels fast but there would be little reaction time against an attack by a direct ascent ASAT. Satellites in LEO are also more susceptible to jamming because they are closer to the emitter, however, the jammer must be within the footprint of the satellite which restricts where it could be positioned on the ground. In addition, the satellite would be within sight and range of the jammer for relatively short periods. A satellite in geostationary orbit is far enough away to provide warning time (3-6 hours) if a ground based ASAT were launched against it. An alternative is for a potential adversary to position a satellite nearby in the same geostationary orbital plane on the pretext of some valid requirement. Sometime afterward the enemy satellite could maneuver quickly to damage or destroy the target satellite. Inclining the orbit slightly at geosynchronous altitude enhances survivability but results in a ground trace of a figure 8 that sacrifices some of the unique advantages of a geostationary orbit. A satellite in a highly elliptical orbit is still susceptible to interception, however, an enemy's attempt to place another satellite into the same orbit would be very suspicious since there are an infinite number of other variations.
8-4 Other Threats From Deliberate Attack, cont'd
Maneuverability and Mobility j. Most satellites have small rocket engines that are used periodically to adjust their orbit and orientation. Some satellites have larger rockets so that more radical changes to their orbit can be made. Maneuvering a satellite can reduce its vulnerability to interception. In addition, sufficient warning of imminent attack is essential. The U.S. Space Surveillance Network is the most comprehensive and capable in the world. It performs functions that would crucial to detecting attacks by other spacecraft. The most difficult situation would be the detection and attack assessment by a direct ascent ASAT attacking a satellite in low Earth orbit. Additional maneuverability of a satellite may require larger rocket engines on the satellite and certainly more fuel which thus reduces the payload weight that can be put into orbit. Autonomous Operations. Most satellites require control from ground stations to maintain the system in optimum operating condition. If some of the functions performed by fixed ground stations and the control segment can be performed on the satellite, then the system acquires a greater degree of autonomy. Autonomous operation also decreases reliance on critical, single node, ground stations.
Reconstitution k. There are two basic ways to reconstitute a satellite constellation after attack. The first is to activate reserve or spare satellites that are maintained in orbit. In many satellite constellations older satellites have been replaced by newer models. The old satellites are often placed into a standby mode to conserve energy and fuel. Although they no longer operate at full capacity or do not have all of the capabilities of the more modern satellites, they are capable of providing some capabilities in emergency situations. The alternative is to launch replacement satellites. Some programs include the construction of one or more extra satellites to be used in case of a launch failure or a failure of a satellite once it is in orbit. In other cases, the satellites on orbit have remained in excellent operating condition far longer than planned. As a result, replacement satellites were not launched as frequently as originally planned yet the satellites continued to be built and delivered on schedule. Replacement launches are difficult because of the shortage of launch vehicles and the considerable time it takes to prepare them for launch.
Hardening l. Hardening involves adding or designing components so that they are more resistant to damage or destruction. Hardening is often associated with increasing the resistance to damage from the effects of nuclear or directed energy weapons but also includes measures to increase survivability against physical attack and naturally occurring environmental effects. Equipment can be designed and constructed to protect from electromagnetic pulse (EMP), lasers, and other weapons. Hardening does not increase the performance of a satellite but it can make it much more difficult for an enemy to destroy or damage. Hardening against a variety of threats is difficult, adds expense to system design, parts and construction, and may result in larger or heavier equipment. The result is a compromise between a device that can be destroyed easily and one that can survive against any threat yet is too large, too heavy and too expensive.
Hardening Materiels m. It is not practical to build equipment that is hardened to survive a direct hit by a nuclear weapon. It is possible, however, to design and build equipment that provides enhanced resistance to damage from electromagnetic pulse and radiation generated by a nuclear explosion. There is no blast shock wave effect in space because there is no atmosphere. Due to the nature of the electromagnetic environment in space and its effect on spacecraft, all satellites have some degree of protection against damage from electromagnetic effects or they will not survive long even with out being attacked. Satellites can be hardened by including filters, Faraday cages, surge arrestors, waveguide cutoffs and use fiberoptic components to increase survivability against upset and surges generated by electromagnetic pulse.
8-4 Other Threats From Deliberate Attack, cont'd
Hardening Against Lasers n. Hardening satellites against the effects of lasers is concentrated on protecting exterior components and protecting various optical and infrared sensors. Reflective surfaces, shutters and non absorbing materials provide some protection for exterior components. Spinning the satellite avoids having one surface continuously exposed to the laser beam but the satellite must be designed to operate while spinning or this will not be a feasible solution. Most optical or infrared sensors on spacecraft are sensitive instruments capable of detecting very low levels of energy at particular frequencies. Laser threats are categorized as being inband or outofband. Inband threat lasers have a frequency that the sensor is capable of detecting. Energy from this type of laser passes through the sensor's filters and lenses until it strikes the detector array. It does not take much concentrated laser energy to overload or damage the sensitive detector array. There are some special filters, shutters, and certain design techniques that can minimize the effects of an inband laser but most result in the sensor not being usable while it is being illuminated. Energy from an outofband laser is usually prevented from entering the sensor by special filters or shutters. Filters can block out the unwanted laser energy but often do so by absorbing the laser energy which is the converted into heat. If the incident laser energy on the filter is strong enough, it is may be possible to destroy it, thus making the sensor unusable or unprotected.
Armor o. Susceptibility to damage from some types of ASAT weapons can be reduced through the use of more robust components and armor. Hardening a satellite to withstand impact with an object the size of a bullet travelling in an opposite direction is difficult due to the very high closing velocities that could occur. A one ounce mass with a closing velocity of 30,000 miles per hour has the equivalent impact momentum of a two pound hammer travelling at 940 miles per hour, all concentrated in a small area.
8-5 Threats Posed By Space Systems to U.S. Military Forces
Introduction a. Space systems are available around the world. It is expected that an adversary will use space systems to enhance its military operations. The space system does not have to belong to an enemy nor be a military system for it to be an asset. It is possible that a space system that is an asset to U.S. military forces could also be an asset to an enemy, i.e., the U.S. military and an adversary may use weather data from a METEOSAT satellite. Or, an adversary could access a U.S. owned and operated satellite such as the GOES weather satellites.
Who has the Ability b. The United States military has more ability to use space systems and products provided by space systems than any other military force in the world, but it is not the only military force that uses space systems to support its operations. Although it is not expected that the U.S. military will lose it preeminent position in the near future, it is expected that foreign military forces will increase their use of space systems, especially civil and commercial systems.
Countries that Can Launch c. As of 1996, the following nations had the ability to launch a satellite into space: United States, C.I.S., China, European Space Agency, Japan, India, Italy, and Israel. As costs decrease, more commercial launch systems are expected to become operational.
Countries that Can Build d. The number of countries with facilities to build satellites is much larger. The United States has the lead in building sophisticated satellites but there is significant competition from many foreign companies. It is expected that the capabilities of foreign firms will continue to grow in number and increase in sophistication of the satellites they can construct. There are many countries and commercial firms that buy a satellite and pay for its launch to acquire space capabilities. This is especially true for satellite based communications systems.
Communications e. Many nations and commercial firms operate satellite communications systems. Most of the world has access to satellite systems through international consortiums such as INTELSAT and INMARSAT. Because of the large number of participating nations in these systems, it is likely that adversaries in future conflicts will have access to INTELSAT and INMARSAT, possible even through the same satellite. Many have already orbited communications systems dedicated to their own uses, or are planning to do so. Space based communications support access is also available to nonowners who are willing to lease or otherwise pay for it. Owned or leased, spacebased communications support to civil, commercial, and military operations is a reality for many countries, and will be for others. Soon, mobile satellite communications systems are expected to become operational. Most will be able to provide communications directly between small handheld receivers similar to cellular telephones network.
Low Resolution Observation Systems f. Low resolution systems provide valuable data over large areas and use a variety of spectral and special sensors to record and report on weather, environment, and terrain conditions. By international agreement all civil weather satellites transmit data in an unencrypted format. Anyone with a proper receiver can receive, process and display data from these systems. Examples of these systems include:
  • Landsat satellites (U.S. commercial system-terrain imaging.) receiving stations are located around the world. The number of licensed stations is increasing. Prior to a conflict foreign governments can purchase Landsat data with little restriction.
  • SPOT satellites (French system-terrain imaging.) have data available commercially.
  • Russia operates multispectral environmental satellites. Data is commercially available.
  • Japan and Europe operate environmental satellites such as JERS and ERS which have visible image and synthetic aperture radar sensors and the data is available commercially.
  • National Oceanographic and Atmospheric Administration (NOAA) polar orbiting weather satellites and Russian Meteor satellites.
  • GOES, METEOSAT and GMS geostationary weather satellites operated by the U.S., Europe, and Japan, respectively.
8-5 Threats Posed By Space Systems to U.S. Military Forces, cont'd
High Resolution Observation Systems g. These consist of satellites with sensors that are capable of providing greater detail than low resolution systems. Most provide data to a central processing facility which then disseminates processed data and products to users. Some are capable of providing data in near real time that can be of immediate value to a military commanders. These are exclusively assets of governments today. In the near future systems with a resolution of less than 5 meters may be commercially.
Warning Systems h. These systems are designed to provide near real time warnings of critical tactical events, such as ballistic missile attack or nuclear detonation. Other than the United States, only Russia is believed to have satellites capable of early detection of an ICBM and that is only within a specific geographic area.
Position and Navigation (POS/NAV) Systems i. The U.S.'s Global Positioning System (GPS) and Russia's GLONASS satellites provide worldwide position and navigation service. GPS's Standard Positioning Service (SPS) is available to anyone with a GPS receiver. No classified codes are needed. Normally accuracy is limited to 76 m Spherical Error Probable (SEP) but can be degraded to much worse accuracy when it is in the national interest. SPS receivers are available commercially from manufacturers around the world GPS's Precision Positioning Service (PPS) provides 16 m SEP accuracy but requires a receiver that is capable of loading classified codes to remove some of the deliberate error in the signal from the GPS satellites. The production of PPS GPS receivers is controlled by the U.S. military and certain U.S. allies participating in the GPS program. The classified codes needed for PPS are generated and distributed by the U.S. In many cases, SPS provides sufficient accuracy to give a military force an advantage.
GLOSNASS g. GLONASS is a space based navigation system that is similar to GPS. It was initiated by the USSR and has been continued by Russia. The accuracy of GLONASS is expected to be better than GPS's SPS but not as good as PPS. Russia has stated that it does not intend to implement a degraded position and navigation service. An adversary of the U.S. could use GLONASS if GPS does not provide the desired accuracy. To date, GLONASS receivers are not widely available.