Mars sample return earth entry system micrometeoroid and orbital debris risk uncertainty analysis

Abstract

Spacecraft designers and operators use micrometeoroid and orbital debris (MMOD) risk assessments to predict the probability that an MMOD particle impact will cause a critical failure to their systems. An important aspect of MMOD risk and associated requirements is the treatment of uncertainty, often difficult to quantify or even estimate for many elements of MMOD risk. There are several sources of uncertainty in every MMOD risk assessment, and previous analyses have addressed some, at least from a qualitative standpoint. This paper describes recent efforts to estimate MMOD risk uncertainty due to uncertainties in inputs to the MMOD risk assessment process for a portion of the planned Mars Sample Return campaign.

The paper explores how sources of uncertainty for the meteoroid environment model and ballistic limit equations were estimated and how applying those uncertainty bounds influenced MMOD risk. Uncertainty bounds for the meteoroid environment were defined by estimating upper and lower bounds for meteoroid flux as a function of heliocentric distance, given by the Meteoroid Engineering Model version 3. Ballistic limit equation uncertainty bounds were given as a percentage increase or decrease in impacting-particle critical diameter. The results demonstrate the relative effect each input source uncertainty had on the overall risk.