Regulatory Development Study: Limits of a Useful Mission

The UK Space Agency embarked on a quest to gain a comprehensive understanding of methods for quantifying the "limits of useful mission" and the permissible deviation from a nominal trajectory. The primary objective was to determine how mission objectives could still be partially achieved despite deviations from the intended trajectory, be it in terms of time, velocity, or other parameters.

In response to this challenge, UK Launch Services Ltd (UKLSL) undertook a thorough study to elucidate the distinction between a "useful" and a "non-useful" mission. This involved analysing data on previous missions where deviations from the intended orbit were allowed, and the mission was not terminated on safety grounds. By examining these instances, UKLSL sought to identify patterns and factors that influenced the decision to continue the mission despite deviations.

To commence the study, UKLSL conducted a meticulous review of historical launch failures, specifically focusing on scenarios where flights were terminated due to the vehicle exceeding pre-defined parameters. Additionally, they analysed cases where a vehicle was permitted to continue its flight, albeit with deviations from its original mission parameters. This comprehensive analysis provided valuable insights into the various scenarios and circumstances under which missions were allowed to proceed despite deviations.

Subsequently, UKLSL evaluated different approaches and methodologies to define flight safety limits and, if possible, establish flight abort rules. By assessing these methodologies, they sought to identify key mission parameters that could be utilised to characterise the limits of a useful mission. This analysis was instrumental in understanding the factors that govern mission success and how deviations from the intended trajectory could still enable partial fulfilment of the primary mission objective.

Through their comprehensive study, UKLSL contributed to the UK Space Agency's quest to understand and quantify the limits of useful missions. By delving into historical data, evaluating methodologies, and identifying mission parameters, UKLSL provided valuable insights that will inform future mission planning and decision-making processes. The outcomes of this study will enable the UK Space Agency to develop robust guidelines and strategies that ensure mission success even in the presence of deviations from the nominal trajectory. 

Keywords: Flight Safety, Vehicle, mission.