Peterson’s prior career was spent with the US Navy as a SONAR operator on nuclear-powered fleet and ballistic submarines. The principles underpinning SONAR are broadly similar to EMDAR: both use passive sensor technology that allow the long-distance detection of other vessels without emitting any active scans that might give their own position away. Peterson was recruited by the ISDC as a Petty Officer and set about adapting his SONAR experience to the brand new field of EMDAR. As the team grew, a technical specialist capable of leading the group as its ‘chief’ was needed and Peterson was selected for the role.