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Hawkeye 360 Cluster 2 satellite (HawkEye 360) As of early 2021, U.S. contractor HawkEye 360 had launched two constellations of RF emitter detecting CubeSats. Shown here are the three vehicles that made-up the company’s second constellation which was launched on 24 January 2021

Owning satellite based ISR for military use is still an exclusive ‘club’, but airborne ISR still provides that most countries need.

by Martin Streetly

Until relatively recently, satellite-based intelligence, surveillance and reconnaissance (ISR) was restricted to an exclusive club that was made-up of the world’s technological and military ‘superpowers’. Here, security considerations, enormous cost and the sheer difficulty in placing something like a 19.5 metre long KH series imaging satellite in orbit ensured the exclusivity of the ‘club’. For those able to capitalise on the technology, the rewards were (and are) enormous, with an American Lockheed KH-11 Kennen/ Crystal system being postulated as having a six centimetre ground sampling distance from an altitude of 155 miles (250 kilometres). Again, orbiting satellites have been relatively invulnerable to attack (although America, China and Russia have all looked at antisatellite technology over time), offer global coverage and total persistence until orbital decay sets in when their power and fuel supplies are exhausted. In this latter context, it is interesting that America’s Space Shuttle was developed partly as a re-usable ‘service station’ to keep the country’s in-orbit fleet of imaging and signals intelligence (SIGINT) satellites operational for as long as possible.

For those countries outside this ‘charmed circle’, air vehicles offer a much more affordable means of collecting ISR data. As much as anything, this has been driven by developments in sensor and business aircraft technology that today enable aircraft such as Textron Aviation’s King Air turboprops or Gulfstream ‘bisjets’ to carry sensor suites that can include surveillance radar, electrooptical (EO) and infra-red (IR) imagers and signals collection equipment in