Space is globally recognised as being critical to economic success, national security, and societal well-being and has recently been identified as a warfighting domain in Australia's Defence Force Structure Plan 2020. The ability to operate with freedom and confidence in the space domain is of strategic importance and careful thought and planning should be given to the technologies, systems and methods needed to ensure this.
Electromagnetic Warfare (EW) is a vital and proven capability for operating successfully in complex, contested environments. In the space domain EW has the potential to be a game changer due to its non-kinetic force protection and force projection capabilities that avoid the generation of space junk.
Space presents us with a new electromagnetic environment where the absence of an atmosphere relaxes constraints associated with electromagnetic propagation, opening up the possibility of new sensing, communication, force protection and force projection capabilities. There is significant potential for technological and strategic surprise, with emerging threats, opportunities and challenges for those nations wishing to operate in the congested and contested ‘Global Commons of Space’.
Space EW will have some fundamental differences. It will operate throughout the entire electromagnetic spectrum (EMS), i.e. will be spectrum ubiquitous, and will be perpetual to match the perpetual nature of the threat landscape. This article discusses some of the potential new technologies, systems and techniques that may emerge and makes the case for the development of a Space EW capability roadmap. It is through such a roadmap that we can ensure that in the space domain, the opportunity will outweigh the threat.
A New EM Environment
Figure 1 is a schematic representation of the atmospheric transmission of electromagnetic radiation from 100nm to 10cm wavelength. Absorption is the dominant mechanism that leads to poor transmission but other factors such as scattering and turbulence can also impact system performance.
Traditionally, any electromagnetic (EM) based systems (e.g. radars, electro-optic imagers and communications systems) with medium to long range performance requirements are restricted to operating in wavebands of very high transmission (known as atmospheric windows). The very low transmission regions are rarely exploited but can support boutique applications such as UV solar blind missile warning, and millimetre wave (mmW) high-bandwidth, short distance, covert communications.
In the absence of an atmosphere it is theoretically possible for mid to long range systems to appear at any wavelength and performance envelopes are no longer limited by effects such as scattering and turbulence. For example: we can expect to see long range radar and communications systems appear across the entire mmW band (1mm-10mm); the Infrared (IR) region is no longer “fragmented” enabling remote spectroscopy across the full IR range, potentially leading to new IR imaging and measurement and signatures intelligence (MASINT) capabilities; and laser systems, free from the atmospheric effects that cause scintillation, beam wander and beam distortion, are likely to have an increased presence for high speed communications, sensing and countermeasures applications.
EW in a new environment
As space faring nations develop their space capabilities, spectrum superiority will be key to maximising opportunities and minimising threats. Space EW faces the significant challenge of operating throughout the entire electromagnetic spectrum, driving the need for new EW techniques, technologies and systems. Insight into the nature of space EW challenges can be gained by placing some of the potential emerging space capabilities in context.
As a first example, in the future we may see the emergence of Artificial Intelligence (AI) enabled sensor network systems embedded in the space environment that are designed to provide a more detailed and timely space situational awareness capability, including information on satellite design and activity. Such systems would consist of passive (EO/IR) sensors coupled with narrow beam mmWave radars and ladars. EW systems such as radar warners receivers and laser warner receivers can provide warning of this occurring and support surveillance countermeasures.
However there are some complex issues to consider including the impact of the broader waveband coverage and the satellite real estate needed to host EW systems in an era where the trend is towards smaller satellites. Possible solutions to consider would be: distributing EW sensors amongst satellites and sharing the data, dedicated EW satellites, and development of multifunction software-defined sensing systems that include EW functions.
Second, as nations establish a presence on the moon there is likely to be a move towards establishing observation systems to monitor the facilities and activity of others. Development of passive countermeasures to this will require significant effort be invested in building signature databases across all wavebands and in understanding the physical (including thermal) characteristics of the environment. For example signature management of surface tracks made by vehicles will present a challenge as these will have a very long half-life and are an effective means of activity monitoring.
Third, communications traffic analysis can also reveal information on activity and intent. Blue force tracking, an essential element of personnel safety, is vulnerable to traffic analysis. The absence of an atmosphere removes the option of exploiting absorption to provide short range, covert communications and will place more emphasis on other techniques such a very narrow beam laser communications.
Space EW must evolve at the same, or at a greater pace, than space capabilities if we are to avoid being in a reactive, rather than proactive mode in responding to threats and challenges. There is a very large and complex range of fundamental science, technology, systems and concepts development that will be required. It is recommended that a detailed roadmap by developed to determine the areas of investment to best evolve a future space EW capability.
Note: Jackie Craig is an adjunct professor at Flinders University and a non-executive director of the SmartSat CRC. Craig previously worked in DSTG and was Chief Electronic Warfare and Radar Division and the founding Chief of Cyber and Electronic Warfare Division.