The Notional Risk Scores Approach to Space Cyber Risk Management

Space is an emerging domain critical to humankind. Correspondingly, space cybersecurity is an emerging field with much research to be done. To help space cybersecurity practitioners better manage cyber risks, The Aerospace Corporation proposed a space cyber risk management approach dubbed Notional Risk Scores (NRS) within their Space Attack Research and Tactic Analysis (SPARTA) framework, with the intent to help quantify the cyber risks associated with space infrastructures and systems. While intended for adoption by practitioners, NRS has not been analyzed with real-world scenarios, putting its effectiveness into question. In this paper we present an algorithmic description of NRS and characterize its use and effectiveness in a case study of space-related cyber incidents and its strengths, weaknesses, and applicability via 72 real-world cyber attack scenarios against space infrastructures and systems.