General Discussion. The linchpin in delivering a critical blow to an enemy system anywhere in the expanse of the air and space environment is accurate detection and targeting. This capability is crucial in providing total battlespace situational awareness. To make this happen, significant advances are required in radar, laser, and infrared detecting and tracking technologies. While "detecting and targeting" imply offensive capabilities, they also lead to formidable defensive capabilities in countering enemy kinetic energy weapon (KEW) and directed energy weapon (DEW) attack.
In order to defend against an ASAT, for example, the defending satellite (or its controlling system) must be able to detect approaching threats in order to defensively react. Defensive traits must go beyond today's satellite hardening and limited space maneuvering. In 2025, space systems must be able to organically detect intruders, have built-in stealth characteristics, and if needed, be able to actively defend against attack. The following concepts explore some system possibilities intended to give the space force commander dominant battlespace awareness.
System Description. Gravity gradiometers are instruments and systems that detect mass density contrasts. Recent gravity gradiometer research has focused on sea-based submarine detection applications.17 This concept goes several leaps forward and proposes its use in space as a passive detection system.
Concept of Operations. With multiple gravity gradiometers located
on multiple satellites in orbit, approaching "foreign bodies"
can be passively detected. Data and measurements gathered could be combined
with data from other detection devices in Kalman filtering or data fusion
algorithms to enhance detection and even identification probabilities.
Figure 3-1. Gravity Gradiometer
Gravity gradiometers embedded in multipurpose satellites or spacecraft will detect approaching bodies. Multiple gradiometer systems can accurately pinpoint foreign body locations for follow-on defensive reactions.
Four critical subtechnologies are identified for feasibility investigations with gravity gradiometers. These are (1) gravity gradiometer technology itself; (2) advanced filtering algorithms to combine data from other sensors to enhance detection, location, and identification of approaching bodies; (3) modeling capabilities to appropriately model gravity gradiometer errors and signals; and (4) simulation capabilities to determine the gravity gradiometer accuracy required as a function of the size and mass distribution of the body under scrutiny, as well as its proximity and maneuver pattern. In order to be able to use the gravity gradiometer in a space detection mode, technology advances must yield a system, which can be deployed in space, capable of detecting an object on the order of 100 kilograms at a range of 100 nautical miles. Reaching this sensitivity by 2025 is an extreme challenge and may be a limiting factor in fielding this technology.
Countermeasures. Synthetic gravity fields may provide effective countermeasures to gravity gradiometer systems. However, the technological leap to "produce" gravity is formidable and not likely by the year 2025. Nonetheless, combining data from other sensors (space based or ground based) to validate organic gravity gradiometer inputs would counter synthetic gravity deceptive attempts.
System Description. The Anti-ASAT system incorporates a host
of sensors embedded on orbiting satellites or spacecraft combined with
an artificial intelligence program to detect approaching bodies.18
Sensors will detect all forms of radiated wave energy (IR, RF, electromagnetic,
etc.). Additionally, the concept design includes ablative and reflective
coatings on the host satellite for defense against directed energy attack.
Figure 3-2. Anti-ASAT System
Concept of Operations. This is a satellite self-protection system. If the satellite or spacecraft is approached or attacked by external threats, onboard protective systems eject matchbox-sized "defenders" to home on the intruder, attach to it, and disable it with shaped charges or degrade it by leaching power or disrupting uplink/downlink commands. Hypothetical design should provide a probability of survival (Ps) of .7 against co-orbital threats, .4 against impact or ASATs, and .25 against energy beams. When placed on stealthy satellites, a measure of stealthiness is lost although Ps increases to .9 against co-orbital ASATs and .6 for impact or ASATs and energy beams.19
Countermeasures. An overwhelming attack could defeat the system's self-protection capabilities and destroy or degrade the satellite.
System Description. Key to any counterspace operation in the
future will be total battlespace awareness. The purpose of the space interdiction
net is to detect satellite transmissions, identify the source of those
transmissions, and find the end user of the information.20
This capability is required in order to selectively deny information to
an adversary from his own military satellite system or a commercial system.
In addition, a space interdiction net will be used to determine whether
damage to US or friendly satellites is a result of malicious action or
natural causes, such as solar flare or asteroid collision. Consisting of
an orbiting grid of satellites capable of continuous coverage of the earth,
the space interdiction net will use a web of interlinked microsat systems
to radiate a very low power force field over the globe. The field generated
by the constellation will act as a blanket around the earth and will be
able to detect any energy penetrating the blanket, seek out the desired
signal, and jam or degrade that portion of the signal which is important.
This force field will be capable of picking up transmissions in a wide
range of frequencies and will use triangulation from three or more satellites
to pinpoint the source. A capability to detect 70 percent of the transmissions
will probably be attainable in 2025. All data deemed not critical to enemy
hostile action is left alone to be received as originated. This selectivity
enables US commanders to take positive military action to deny an enemy
critical information without disrupting nonmilitary information traffic.
Figure 3-3. Space Interdiction Net.
In 2025, the number of satellites orbiting the earth will rise dramatically (increasing by 25 percent between 1999 and 2005)21 and commercial systems will form the backbone of the space information network. The key to performing counterspace operations in this environment will be the ability to identify the critical information being transmitted to an enemy. Upon detection of hostile satellite signals, the interdiction grid will be able to deploy a number of countermeasures ranging from jamming and electronic warfare to destruction via kinetic or directed energy weapons. These actions ultimately keep the end user from capitalizing on critical information from his spaceborne assets.
From a technology standpoint, the power source for this system of integrated sensor network is the most daunting challenge. Battery technology may not advance enough by 2025 to provide continuous power to the system. Solar power can be used a majority of the time, but battery technology is still required for times when sensors are out of view of the sun. A possibility is to use a thin film reflector on orbit to light solar cells on the sensor satellites as they orbit in the shadow of the earth (see the solar optical weapon concept presented later in this paper).
As shown by a variety of concepts presented in this paper, there are a wide variety of ways to disrupt, deny, degrade, or destroy satellite transmissions at the source. However, these methods are not selective in that they deny information to all users. The detection and interdiction system will be capable of specifically identifying only that information which is being used against the US or its allies. This information can then be used by field commanders and the national command authorities (NCA) to determine whether or not to take action against the satellite itself or its owners. In many cases, the "owners" will be known, as in the case of multinational corporations who operate satellites as part of their business infrastructure. Again, the spectrum of options ranges from soft kill to hard kill.
Another particularly interesting possibility is the modification of the ionosphere to disrupt communications. A number of methods, such as chemical vapor injection and heating or charging via electromagnetic radiation or particle beams, have been proposed to modify the ionosphere.22 Because ionospheric properties directly affect high-frequency communications, an artificially created ionization region could conceivably disrupt an enemy's electromagnetic transmissions. Offensive interference of this kind would likely be indistinguishable from naturally occurring space weather. The capability to create ionization regions could also be used to detect and precisely locate the source of transmissions.
In order to interdict specific signals, the space interdiction net will be capable of projecting a force field between the target and the receiver. This force field will be in the form of a magnetic field or charged particle cloud. Another possible means of surgically removing specific transmissions is a precision molecular particle which, using a nanotech computer brain, follows the data stream to the source. Once at the origination point, the smart particle destroys the frequency bandwidth on which the critical data is being transmitted. We recognize that technology to dissect transmissions at the molecular particle level may not be achieved by 2025 but once achieved will add dramatic leap in counterspace capabilities.
This concept relies on a tightly integrated net of satellites operating in low earth orbit (LEO). The system must be placed in a roughly 250-300 nautical mile orbit in order to be able to detect transmissions from major orbital regions from low earth to geosynchronous. In order to provide continuous coverage to all points on earth, the system will consist of three interlinked constellations of 66 satellites for a total of 198 satellites. All satellites will be interlinked with each individual satellite capable of assuming control of a "hot" sector, one in which hostile transmissions are detected. Satellites will consist of a power system and phased array antenna to project the low energy detection field. In addition, a very high-speed computer will integrate the incoming detection data and correlate the data to a source through triangulation. Finally, a directional antenna, on order from the command and control subsystem, will project a controlled cloud of charged particles to a point in the sky. The end result is a large charged particle cloud or ionization region placed precisely between the sender and receiver. A further leap would use molecular sensors and computers to lead individual molecules in the charged particle cloud to seek out and destroy specific bits of information from the data stream. The idea of surgical strike has now been taken to the molecular level.
The limiting factor in making the space interdiction net a reality will be the ability to project low power fields over large areas in space. A number of evolutionary advances in space weather forecasting and observation are required to make ionospheric exploitation a reality. The high-speed computer technology necessary to control the smart particles should be available in 2025. In addition, nanotechnology computers may make possible the development of smart charged particles which will be capable of finding and destroying signals. The combination of very low orbits (prone to orbital decay) and the high number of satellites required to form the system will drive the need for a very high resupply rate. This in turn points to the need for a very robust launch capability.
Concept of Operations. The space interdiction net will be in constant orbit around the earth. The system will monitor space transmissions continually while especially looking for strategic indicators which may be warning of impending escalation. With the capability to perform selective offensive counterspace, the activation of the system itself can act as a deterrent to further aggression. Intelligence inputs will give the system an initial estimate of enemy space capabilities which will enable the detection and interdiction system to focus on certain satellite constellations.
The grid will be capable of interrupting key information from all types of satellites including communication satellites, imagery satellites, and weather satellites. It will be closely integrated with the C4I system to allow commanders at all levels near instant data on which enemy capabilities have been negated. In addition, the grid will be linked to the other assets which makeup the counterspace system. If precision signal blocking is not necessary, alternate counterspace systems such as directed energy or parasite microsatellites (described later as robo-bugs) can be employed to disrupt or destroy the enemy's space capability. In order to ensure the grid is constantly maintained, a number of on-orbit spares will be placed in parking orbits to be used as needed. A quick-turn launch capability is required to keep the system operationally ready due to expected orbital decay of the LEO satellites which makeup the system. The interdiction net must be capable of integrating with the command and control system as well as the intelligence system.
Countermeasures. An important countermeasure to this type of system lies in the ability to disrupt or create holes in the detection field. Encryption methods may be capable of making signals hard to attack with smart molecular munitions. If the sender can disguise transmissions or make them capable of changing while en route to the receiver, it will be difficult to identify and attack the right data. Maybe the simplest way to defeat this type of system would be through redundancy via the proliferation of small satellites capable of performing specific missions. Thus, if one system is detected and jammed by the interdiction net, the mission can be accomplished by any number of other satellites capable of transmitting the critical information. This method also complicates the ability to target systems by increasing the cost associated with disrupting or negating a large number of miniature systems operating over a vast battlespace. Should ionospheric disruption become a reality, it could be turned against the space interdiction net to disrupt the low power field or interrupt essential command and control functions.
General Discussion. Miniaturization is about the age old quest to do more with less, in military parlance, to package more capability in a smaller package. In space, the main reason for miniaturization is weight savings-the ability to maximize precious spacelift resources. This in turn reduces the cost of space systems. Another reason for miniaturization in space is redundancy. A constellation of small satellites performing parcels of the mission is not so vulnerable as a mega-satellite tasked with doing it all. Finally, miniaturization in space opens up new avenues to exploit enemy space systems. It is in this realm that miniaturization can make a true contribution to the counterspace mission. Of note is the urgent desire for commercial industry to exploit miniaturization. Dr Tom Velez, in the keynote address at the eighth annual American Institute of Aeronautics and Astronautics (AIAA) conference on small satellites noted that the small satellite or "smallsat" industry is growing "for reasons that are not political, not military, not scientific, but commercial . . . they're cheaper and more capable of providing user services."23 This commercial interest should aid immeasurably in the development of technologies and systems that will enable a robust counterspace capability in 2025.
The electronics industry has shown the ability to double the number of transistors on a microchip every 18 months. This trend has driven a dramatic revolution in electronics. Researchers note that the ability to "manufacture millions of microscopic elements in an area no larger than a postage stamp" has inspired further miniaturization technology.24
Two emerging technologies show particular promise in making spacecraft smaller and more capable. The first, microtechnology, is the combination of miniaturized mechanical and electric components in microelectromechanical systems (MEMS). The Scientific Advisory Board's New World Vistas Space Technology Volume, report labels MEMS as the next step in the microelectronics revolution in which multiple functions are integrated on a microchip.25 An example of a future MEMS system is on-chip optics which will be used to provide agile target recognition and tracking.
The second technology, nanotechnology, is not nearly as developed. Its chief proponent, Eric Drexler, describes it as "taking what we're very familiar with on a macroscopic level and doing that on a vastly smaller scale using the basic building blocks of matter."26 Drexler notes that instead of taking something large, like a silicon wafer, and making it small, nanotechnology starts with molecules and atoms and builds up in tinkertoy fashion. The results will go far beyond simply making atom-scale computers. The New World Vistas Materials Volume report notes nanobased processing could provide advanced electro-optical materials, molecular scale sensors, and dynamic stealth materials.27
Nanotechnology offers the capability to build molecule-size factories capable of churning out thousands of specialized nanomachines. Researchers estimate that it will take 20 to 30 years to achieve practical nanotechnology results. The following section describes the link between advances in miniaturization and proposed systems to perform the counterspace mission. Two counterspace concepts with miniaturization as the key enabling technology are promising. Satellite bodyguards-fleets of small satellite sentries-will protect high value space assets. Robo-bugs-parasite microsatellites capable of operating on or near enemy satellites-will use jamming and electronic warfare methods to disrupt and degrade information transmitted from enemy space systems. A description of these potential systems along with a proposed concept of operations follows.
