Advances in Astronautics Science and Technology最新文献

The Large Envelope Advanced Parachute System (LEAPS) is developed as a means of recovering the flight data to prove that a student-built sounding rocket, Stratos IV, has reached space. Several design modifications are outlined in this work. The drogue parachute is deployed using a hot gas deployment system to save mass and volume and to increase reliability. The main parachute has been changed to a Disk-Gap-Band parachute as it is better testable in the Open Jet Facility, a subsonic wind tunnel of Delft University of Technology. A heat shield is included to protect the parachute system during atmospheric re-entry. The key benefit of this work is creating a reliable and supersonic parachute recovery system for the safe recovery of flight data located in the sounding rocket's nose cone.

In this paper, a kind of micro–nanosatellite electromagnetic docking device is designed and a configuration of electromagnet with iron-core is proposed. Compared with the coreless coil, the electromagnetic force within the docking range can be significantly increased. To resolve the problem of limited capacity of electromagnet attitude correction, a type of taper hole–taper rod matching mechanism is designed to limit non-docking axial motion for docking in electromechanical coordination. Through the ground experiment, the function of electromagnetic docking device is verified.

To accurately determine the loads and energy absorption capability, which plays a vital role in the design and optimization process of a new landing gear system for a lunar lander, a new approach of landing impact dynamic analysis using nonlinear finite element method is developed. Abaqus/Explicit is selected to simulate the soft-landing event for its excellent nonlinear, transient dynamics capabilities. The aluminum honeycomb shock absorber model is established by plastic crushable foam material model and the lunar soil is built by Drucker–Prager/Cap material model. Finally, the load at connector between structure and landing gear and acceleration response of structure and dissipated energy by the shock absorber and lunar soil are presented.

Large cracks may occur in the pressured module under the impacts of micro-meteors and space debris during orbit, which may cause rapid instable extension of cracks under the internal pressure load. To reduce the risk, the design criterion of crack stop is put forward, and the mechanism of fracture extension, simulation analysis and test verification method are studied. At the same time, the critical crack length and the influence of different parameters on it are obtained by the analysis and test of a typical integrally stiffened structure. It is proved that the structure design of the integrally stiffened structure for a spacecraft has a good crack stop performance.

The orbital replacement unit and its core technology are the technical basis for the future spacecraft to achieve acceptable on-orbit service and support expansion and upgrading. It can realize on-orbit replacement, replenishment of consumables and other operations, effectively extend the service life of the target spacecraft and maintain the continuity of the mission. In this paper, the mechanical structure of the three-jaw docking interface has been taken as the object and designed the docking interface of the orbital replacement unit which is not mainly dependent on the mechanical arm insertion. The dynamic performance of the docking process was simulated as well. The research work can provide a reference for the design and application of the orbital replacement unit.

The dynamic characteristics of a large deployable support arm with uncertain parameters are studied. Due to the processing, manufacturing and other reasons, uncertainty is common in the actual structure, especially for the main bearing structure of high-precision imaging, the uncertainty becomes an important influence that cannot be ignored. In this paper, the modified perturbation method is used to study the change in the structural dynamic characteristics when the elastic modulus of the support arm has a small parameter variation, and the Monte Carlo simulation is used to verify the comparison. The natural vibration characteristics of the support arm structure are measured from the perspective of the statistical characteristics of probability.

Lightweight structures composed of a closed shell and internal lattice infill are highly desirable in satellites on account of their superior specific stiffness and buckling strength, which are brought about by the sandwich effect. These lattice structures can be fabricated by various additive manufacturing techniques, such as selective laser melting (SLM). However, the sub-millimeter-scale shell thickness and lattice strut diameter of the fabricated structure often deviate from the designed dimensions and lead to noteworthy discrepancies between the resonance frequencies of the fabricated structure and those of the initial design model. In this work, a bracket structure for a satellite is designed via topology optimization-based lattice infill approach and fabricated using SLM. A resonance frequency prediction approach based on X-ray micro-computed tomography and the stiffness equivalence is then proposed. Vibration tests are conducted to obtain the resonance frequencies of the fabricated structure. The prediction errors of resonance frequencies for the first three modes are less than 1%, whereas that of the traditional approach based on finite element analysis is as large as 14%.

Lunar Zebro’s mission is heading the race for deploying the world’s smallest and lightest swarm of nanorovers on the surface of Moon. The concept validation of a single nanorover is of crucial importance, as it will be the launching pad for deploying a swarm of those nanorovers thereafter. Then, they will get connected in a network, acting as a single device and performing scientific missions analyzing data from remote points on the Moon’s surface. In the current study, the complete set of thermo-mechanical-radiation analyses for Lunar Zebro nanorovers are carried out. These range from the Ground Segment to the Moon environment, taking also into account the extreme mechanical and thermal environment at launch-transit conditions when the nanorover is attached to the lander. An innovative ray tracing method to evaluate the effect of the thermal environment on the Lunar Zebro nanorovers is explained in this paper. Material choices, structural design, and mechanical/thermal strategies for the nanorover to overcome the launch, space and Moon’s conditions are shown. The different analyses methods used, expected loads and results obtained should serve as a baseline for evaluating the behaviour of other small devices attached to a lander when aiming for any space mission. More specifically, for those aiming to go to the Moon, the environmental and mechanical expectations here can also be implemented. The ultimate outcome of the paper is the environmental survivability assurance from an analytical perspective of these nanorovers when being sent to the Moon. The validation of the survivability of a single nanorover will be a breakthrough in the space swarm robotics’ field, resulting in the successful performance of the lightest swarm of nanorovers ever deployed on the Moon’s surface.

The periodic lattice structure has obvious advantages in lightweight and multi-functional design. With the development of manufacturing technology, especially the development of selective laser melting, the periodic lattice structure has been more extensively used, and attracts more attention in studying its structural behavior. According to the characteristics of periodic lattice structure, ABAQUS is used to establish its geometric model, and the mechanical properties are simulated and analyzed under compression. Considering three kinds of cantilever beams with solid, periodic lattice and rubber-filled periodic lattice as examples, and comparing with the theoretical results of modal frequencies, the simulation method of the periodic lattice structure is improved. The simulation analysis method is used to analyze the change of mechanical parameters and the change of the damping characteristics of the three types of cantilever beams caused by the dimension difference in different directions. The simulation results can provide a basis for the performance test of the periodic lattice structure and provide a reference for the design of the periodic lattice structure which meets the performance requirements.

Bolt connection in-situ measurement refers to the field measurement of bolt preload without changing the original bolt connection state. At present, the technologies that can be applied to bolt connection in-situ measurement mainly include piezoelectric impedance method, acoustic emission method, ultrasonic method, optical fiber sensing method, etc. This paper summarizes the research status of these measurement methods, analyzes their measurement principle, key technologies, advantages and disadvantages and scope of application, and finally gives the development trend of threaded connection in-situ measurement technology.