Space-based gravitational-wave detection missions typically deploy three spacecraft in a widely spaced triangular formation in deep-space heliocentric or high Earth orbits. Maintaining high-precision coherence across this distributed, large-scale, and multi-degree-of-freedom system is critical to long-term, stable, and precise detector operations. High-accuracy orbit determination is foundational to mission success. Although a variety of tracking and measurement techniques exist, achievable orbit-determination accuracy is constrained by tracking coverage, systematic measurement errors, formation geometry, orbit-control capability, and the geometry of ground-based tracking networks. This paper presents a systematic overview of orbit-determination requirements for different mission architectures, analyses the performance and technical characteristics of ground-based and space-based tracking methods applicable to spacecraft in heliocentric and geocentric orbits, and discusses current challenges and future directions in high-precision orbit determination technologies to enable reliable, precise operation of space-based gravitational-wave detectors.
Integrating carbide slag (CS), fly ash, and coal gangue to synthesize fully solid waste foam ceramics provides a viable solid waste management solution. This study analyzes sintering parameters and CS dosage effects on foam ceramic properties: physical traits, pore structure, micromorphology, mineral phases, and sintering behavior. The findings reveal that the carbon content in coal gangue and the Fe2O3 present in fly ash function as foaming agents, facilitating a reaction that generates CO2, thereby inducing a foaming effect. Upon calcination, CS yields CaO, which acts as a flux; an increase in CS content correlates with a reduction in the viscosity of the foam ceramic melt, a decrease in porosity, and an enhancement in thermal conductivity. In terms of sintering parameters, higher sintering temperatures and longer dwell times are conducive to the foaming of ceramics. However, excessively high temperatures and prolonged durations may compromise the structural integrity of the foam ceramics. Optimal performance occurs at 29 wt
To effectively address vibration issues in aero-engine blisks, this study establishes a lumped parameter dynamic model (LPDM) of mistuned integrally turbine blisk with hard-coating and bladed multi-packet shrouds (MITB-HC-BMPSs), systematically investigating the variation laws of modal and vibration characteristics under different mistuning strengths. There are two configurational models on the LPDM considering blade stiffness mistuning, that is, Style 1 (MITB-HC without BMPSs) and Style 2 (MITB-HC-BMPSs). The BMPSs are introduced to connect adjacent blades, forming coupled groups to enhance inter-blade stiffness coupling. The effects of HC and BMPSs on natural frequencies, modal localization, and resonant responses are analyzed, with solutions validated against existing literature. Results show that mistuning has negligible influence on natural frequencies but significantly induces modal shape and forced response localization, with severity increasing as mistuning strength rises. Notably, the hybrid system of HC and BMPSs demonstrates superior vibration reduction: compared with single measures, it more significantly weakens vibration localization. The HC reduces system stiffness and dissipates vibrational energy, while BMPSs enhance structural coupling to mitigate stiffness heterogeneity. This study furnishes both theoretical foundation and engineering guidance for the vibration-damping optimization design of ITB with composite material structures in aero-engines.
Needle-punching is an effective route for introducing Z-direction fibers into preforms for carbon/carbon (C/C) composites, but excessive needling can also damage the continuity of in-plane fiber bundles. To address the resulting multi-objective conflicts among mechanical properties, this study developed a collaborative optimization strategy integrating response surface methodology (RSM), multi-objective hippopotamus optimization (MOHO), and multi-attribute decision-making. Based on the Box–Behnken Design, second-order regression models correlating needling depth, needling density, and carbon cloth areal density with tensile, compressive, and flexural strengths were constructed. The results showed that these properties exhibited different sensitivities to the process parameters, reflecting the trade-off between Z-direction reinforcement and in-plane fiber damage and identifying a compromise process window rather than a single-property optimum. For the present optimization problem, MOHO was used to generate the Pareto non-dominated solution set and, compared with the representative baseline NSGA-II, yielded a more uniformly distributed Pareto solution set and a better compromise-ranking result. Experimental verification demonstrated that under the optimized combination (needling depth 17 mm, needling density 22 punches/cm2, and carbon cloth areal density 377 g/m2), the comprehensive mechanical properties achieved an optimal balance with a maximum prediction error of 5.85
