## 1 Introduction
### Background on Previous Literature Assessments, including Findings, Recommendations, and Limits  
This study is part of a line of research that aims to monitor the evolution of research and knowledge in the field of safeguarding cultural and natural heritage using satellite RS technologies. As such, this line of research reconstructs the long-term trends in the use of specific methodologies and tools, as well as in the evolution of the geographical area of analysis and the types of heritage places considered. Studies in the field eventually provide recommendations on how to redirect the analyses, introduce new tools and approaches, and possibly improve the quality of protection and safeguarding of cultural and natural heritage. The exercises aimed to monitor the evolution of the literature focusing on this topic that has developed over the last decade, with the first studies conducted by [7] on the impact of RS on the wider archaeological field, up to the most recent research study carried out by [10], from which this research takes its cue. Table 1 collects the literature assessments mentioned above and a summary of the outcome(s) achieved. However, it must be kept in mind that, in many cases, the goal of these studies was to measure the entire range of RS applications for archaeology and cultural heritage (such as sites or landscape features detection), and therefore, it is not possible to extract the trends relating to studies on hazards to cultural heritage. Of these papers, some focused on advances in the use of specific types of satellite imagery and/or techniques for their processing and the generation of value-added products, such as radar and maps of structural deformation [6; 11; 12; 13], while others investigated the potential of online platforms such as Google Earth [5]. Several studies also evaluated the role and validity of big data repositories to organize and manage a large quantity of satellite imagery [7; 11; 13]. In other cases, the main focus was the relevance of multidisciplinary collaborations [7; 11], as well as the importance of establishing common practices for data processing and investing in dissemination and capacity building [4; 12; 14]. Towards such an ambitious goal of effective user uptake, the engagement of end users in the design and implementation of RS/EO-based solutions is frequently called for. However, limited evidence was found in the scientific literature [4; 13], and most of the successful use cases of technological transfer relied on mediation by scientific champions [4; 11; 13]. Finally, it is worth highlighting that a recent study [10] highlighted a third significant element, meaning the discrepancy between the types of damage that received the greatest attention in terms of scientific research and policies and the most impactful ones in terms of the number of damaged sites. Basically, several common hazard factors are well known to cause damage and require significant investments from heritage bodies and institutions in charge of daily maintenance and conservation (e.g., local conditions, including micro-organisms, wind, rain, or humidity; urban sprawl; or agricultural practices). However, there are only a few examples of evidence in the scientific literature that these were the primary threats for which RS and EO technologies were used, compared to those damages whose impacts are found to be more disastrous and devastating, albeit limited in time and linked to specific extraordinary events (e.g., earthquakes, landslides). The outcomes of these studies may be summarized according to three main recommendations:  
1. A necessity to pay more attention to matching the properties of current and future satellites with the needs and questions of archaeological research and built-heritage conservation practice. 2. A necessity to raise awareness among the multiple stakeholders revolving around the wider field of heritage on the range of uses of available satellites via more investments in training and capacity building. 3.