# Cyber Resilience Limitations in Space Systems Design Process: Insights from Space Designers
## 2 Literature Review  
The engineering of large-scale, complex systems such as spacecraft or other cyber-physical systems (CPS) demands sophisticated decision making and coordination across all roles and stages of the engineering life cycle [13]. Operating in hostile environments, space systems are critical to national security, communications, and infrastructure, making them particularly vulnerable to advanced cyber threats due to their reliance on cyber resources [14]. A key responsibility of engineers in space systems is to integrate and validate resilience from the earliest stages of design [31]. Therefore, developing strategies to ensure the system can withstand, recover, and adapt to potential cyber threats or failures is essential [35; 36]. The National Institute of Standards and Technology (NIST) defines cyber resilience as _\"the ability to anticipate, withstand, recover from, and adapt to adverse conditions, stresses, attacks, or compromises on systems that use or are enabled by cyber resources\"_[37]. Cyber resilience ensures system recovery by integrating cyber infrastructure's interconnected hardware, software, and sensing components. It serves as a bridge between maintaining system operations and ensuring mission execution. [PERSON] et al. [38] define cyber resilience as _\"the ability to continuously deliver the intended outcome despite adverse cyber events\"_. This means an information system can return to an operational state during and after degradation, whether caused by a deliberate cyber-attack or a natural disaster. The critical distinction between the two is the ability to model natural failures versus cyber-attack unpredictability [38]. Therefore, addressing safety and security design from the beginning of the system development cycle and throughout its phases is essential and advantageous. Hence, the discipline of systems engineering (SE) was introduced to manage and unite multidisciplinary engineering teams [39]. SE aims to optimally understand and gather customer requirements early in the development life cycle and document these requirements in a universal modelling language [40]. Cybersecurity and cyber resilience challenges for space systems are not unique to the space industry but are compounded by several factors. Space systems often serve as single points of failure for various industry sectors. The problem becomes more significant with the need for comprehensive cybersecurity standards and regulations for space [41], complex supply chains and prolonged system life cycles frequently employing commercial off-the-shelf technology [31]. Furthermore, a highly specialised workforce is required for the space sector [42], which is challenging to produce with limited resources. Therefore, these factors collectively make the cybersecurity of space systems a unique challenge and mainly an attractive target for state and non-state actors. Addressing these challenges requires a joint effort to develop robust cybersecurity measures tailored to the space infrastructure's specific needs and vulnerabilities [41]. The space industry has undergone significant transformation due to the rapid advancement of digital technologies and the increasing integration of cyber-physical systems (CPSs). Although these changes offer significant opportunities for innovation and growth, they also introduce a new set of cybersecurity challenges not previously encountered in traditionally isolated and analogue space systems. The once-held belief that the sophistication of space technology alone would provide sufficient protection against cyber threats has been shattered, as evidenced by the lack of special cybersecurity measures in early satellite constellations like Iridium, which provided services to the Pentagon [43]. Space infrastructure is vulnerable to a wide range of cyber threats that were never anticipated during their initial design phases [44]. The advent of digital technologies has significantly expanded the attack surface of space systems.