Read “Arguing The (Safety) Case(s) For Space” by Dr Andy Quinn, which contends that safety cases can assist, rather than hinder, regulators and operators alike.
Space safety demands that appropriate levels of rigour are applied to license applications in order to demonstrate that the ‘system’ (spaceport, operator, vehicle etc.) is compliant to the stated requirements. As there are different and novel space vehicles, it is clear that prescriptive requirements are not appropriate and that performance (and risk) based requirements are more suitable. In the US, the FAA-AST regulations are not prescriptive and require an applicant to submit a Safety Review Document to cover the key regulatory requirements. The document’s main headings relate to relevant Code of Federal Regulations Part 400 requirements and therefore the applicant’s descriptions and ‘solutions’ to each requirement are essentially the compliance statements (or evidence). The document could therefore be described as the ‘safety case’; or can it?
A safety case can mean different things to different people, in different countries. The ICAO definition is ‘A document which provides substantial evidence that the system to which it pertains meets its safety objectives’. In the UK, the term ‘Safety Case’ is used in respect of a set of one or more documents that include claims, arguments and evidence that a system is safe. Another UK definition is that a safety case is defined as ‘a structured argument supported by a body of evidence that provides a compelling, comprehensible and valid case that a system is safe for a given application in a given operating environment.
The supporting arguments are the spine of a safety case as these explain the rationale of how lower-level goals (or claims) can help substantiate the overall goal (of safety/compliance) and as well as explaining how the evidence can be interpreted to meet the goals.
The paper presents different safety case formats and the rationale why, if properly argued (constructed), safety cases can assist, rather than hinder, regulators and operators alike. The author of this paper contends that regulations for space activities should be performance based (and not overly prescriptive) and that a formal and structured argument can assist regulators in assessing the compliance to appropriately rationalised requirements and a structured argument, with justifications and assumptions can assist the operator’s case for award of a launch license.