MMX rover MECSS - separation from the mothership: multibody simulation analysis of the ejection

Abstract This is a report about the simulation study of a lightweight rover being separated from a larger spacecraft in vicinity of a small Solar system body. Monte Carlo simulation and statistical analysis estimate the rate of requirement violation depending on uncertain rover and separation mechanism parameters. During the rover development phase, the full Monte Carlo analysis is only done with a simplified model. The first iterations show relatively high probability of non-compliance with requirements. Model refinement and more precise hardware values lead to the final assessment that separation meets the requirements within a $\sim 2$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>∼</mml:mo> <mml:mn>2</mml:mn> </mml:math> $\sigma $ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>σ</mml:mi> </mml:math> region. Another key result is the identification of relevant and irrelevant effects on the spacecraft rover separation. A more detailed model serves for analysis of selected samples during the development phase. For this model, a full Monte Carlo analysis is only done close to the end once the parameter ranges are fixed, mostly for time reasons. This more detailed analysis in general confirms the $\sim 2$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>∼</mml:mo> <mml:mn>2</mml:mn> </mml:math> $\sigma $ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>σ</mml:mi> </mml:math> requirement meeting. The main difference with the simplified model is the much larger number of outliers, a few of which also violate the allocated volume for the rover in proximity of the mothership.