Sensitivity Analysis of The Long-Term Evolution of the Space Debris Population in Leo

Abstract

ABSTRACT Since launch of Sputnik-I in 1957, amount of space debris in Earth's orbit has steadily increased. Historically, primary sources of space debris in Earth's orbit were (a) accidental and intentional break-ups which produce long-lasting debris and (b) debris released intentionally during operation of launch vehicle orbital stages and spacecraft. In future, fragments generated by collisions are expected to be a significant source of space debris. As described by Kessler and Cour-Palais in their 1978 seminal paper Collision Frequency of Artificial Satellites: The Creation of a Debris Belt , amount of space debris in Earth's orbit may reach a tipping point in which future space debris population may be dominated by fragments produced by mutual collisions between objects already present in population. This cascade effect is commonly known as the Kessler Syndrome. In recent years, much of work done to model long-term evolution of space debris population aimed to understand effectiveness of mitigation measures in constraining growth of space debris population. Such work have highlighted potential ineffectiveness of mitigation measures alone to stabilise growth of space debris population in Low Earth Orbit (LEO), and has therefore suggested need to investigate more aggressive measures, such as active removal of space debris from environment, that may be used to reach such stabilisation. The objective of work that we present in this paper is to assess effect of four sources of uncertainties (i.e. solar and geomagnetic activity, break-up model, collision prediction algorithm and post mission disposal compliance rate) on long term evolution of space debris population. This study has been done via sensitivity analysis, where uncertainties affecting considered uncertainty sources have been defined. Through comparative analysis of each of studied scenarios, in terms of population growth and long-term dynamics of effective number of LEO objects, we want to characterize and quantify effect of such uncertainty sources on long term projections of space debris population performed with up to date evolutionary models. This characterization and quantification is a first necessary step to be able to study robustness of mitigation and remediation measures to uncertainties affecting long term evolution of space debris population.