Multiple-input–multiple-output (MIMO) vibration qualification tests can recreate operating conditions more accurately than single-axis tests, though it is challenging to know if the test is conservative. In addition, MIMO specifications are often difficult to reproduce in the laboratory and may only represent a single load case among many that are possible. This paper presents a method for generating a controllable MIMO environment specification that conservatively reconstructs damage across multiple operational conditions. Tests are simulated on a finite element model case study, and stress and fatigue damage are calculated, demonstrating the method’s ability to provide reasonable levels of conservatism compared to traditional testing approaches. The method is also applied to an experimental case study, showing that it is applicable to real systems.
The gravity tractor is an asteroid deflection technology that uses the mutual gravity between a spacecraft and a small body to perturb the body’s trajectory. We develop low-fidelity and high-fidelity models to track the effects of a gravity tractor on a target body. As a case study, we simulate a demonstration mission to the binary asteroid system (162000) 1990 OS. We derive a predictive metric for gravity tractor effectiveness that directly compares changes made to an asteroid moon’s orbit about its primary to changes made to the heliocentric orbit of a single asteroid. We also introduce the push–pull efficiency parameter, which may be used to evaluate gravity tractor effectiveness in the same way that the momentum enhancement factor is used for the kinetic impactor. We find that the gravity tractor efficiency is independent of the target’s spin state for the cases we examine, being equally effective for tumbling and relaxed targets. For 1990 OS, we find that the push–pull efficiency parameter is maximized when hovering 4.5 volume-equivalent radii from the target center. Additionally, we find control strategies for gravity tractors with chemical propulsion systems that are viable and robust to model-error disturbances up to 50% as strong as the modeled dynamics.
Orbital launch frequencies are projected to increase significantly in the next decade to meet the growing demand for commercial satellite services, sovereign defense capabilities, and environmental monitoring data. Launch providers have reintroduced reusable launch systems (RLVs) to minimize costs, turnaround time, and environmental impacts. Thus, efficient and economical methods to assess postflight performance and future usability after encountering the extreme aerothermal environment through reentry are critical. The field of postflight thermal analysis lacks a comprehensive systematic review of in situ thermal measurement methodologies, presenting a crucial knowledge gap in aerospace and thermal engineering research. This review addresses this need by providing a comprehensive examination of existing in situ thermal measurement techniques against a list of criteria, offering researchers and engineers a structured framework for method selection and comparative analysis. Through a systematic synthesis of current literature, we evaluate five thermal measurement methods, highlighting their strengths, limitations, and contextual applicability.
