Debris Capture Research Articles

Single- and Multinozzle Plume Impingement to Detumble Space Debris

The management of space debris is increasingly crucial for ensuring the safety of space missions by mitigating collision risks. Most proposed debris management systems involve the capture and deorbiting of debris. However, it is also essential to eliminate any residual rotation and nutation of the debris to perform capture without accidents. The current work examines the effectiveness of thruster plume impingement for despinning space debris. A proof-of-concept study of plume impingement dynamics is conducted on a rectangular prism target using single- and multiple-nozzle arrangements for different target offsets and orientations. The three-dimensional simulation is carried out using the open-source Direct Simulation Monte Carlo code SPARTA. Staging and dynamic grid adaptation techniques are incorporated to obtain high-resolution results for the multiscale problem. It is observed that the plume–plume interaction in the multinozzle configuration leads to the beneficial formation of a relatively narrow beam of flow interacting with the target; that is, a multinozzle plume exerts a more concentrated directed force, which imparts greater countertorque across a broader spectrum of target orientations than a single-nozzle plume.

Numerical and experimental study on effects of net-bullet ejection angles and initial distances on space-debris capture

The increasing volume of space debris in the outer space poses a significant threat to operational spacecraft. Hence, net capture systems have emerged as a promising technique for removing space debris. These systems operate by deploying a net to envelop and capture the debris. The effectiveness of debris capture using nets depends on ejection parameters such as speed, ejection angle, and the crucial initial distance between the net and debris. Simulations are performed to examine various scenarios of active debris removal. In addition, the experiments involved meticulously calibrated net and debris ejector systems, where bullets are utilized for net deployment by varying the angle of bullet ejection (θ). The net trajectory is determined using simplified equations of motion, while considering both the ejection dynamics and its interaction with the debris. The findings of this study reveal the correlations between the initial parameters and net performance pertaining to space debris capture. Larger ejection angles and greater distances between the net and the debris-hindered debris capture. Despite slight simultaneous net and debris ejection delays, the results of the real-world experiments validated the simulation results.

A novel tether-net configuration with double-linked bullets for suppressing reshrinking motion after full deployment

Tether-nets have attracted considerable attention as tools for capturing space debris. However, owing to the lack of aerodynamic drag to resist collapse in space, tether-nets tend to shrink back after deployment because of tension. Various strategies have been proposed to suppress this reshrinking motion before debris capture, such as equipping bullets with thruster modules to control their trajectory after ejection and incorporating a bullet ejection-angle adjustment mechanism. However, these approaches complicate the tether-net design and/or ejection systems. In this study, a novel tether-net configuration comprising double-linked bullets, wherein the inner and outer bullets are connected via a tether, was proposed to prevent the tether-net from reshrinking after full deployment. Upon full deployment, as the bullets start to rebound from impulsive tension, the outer bullets fly outward, pulling the inner bullets and exchanging momentum to suppress their rebounding motion. The effectiveness of the double-linked bullets in suppressing the reshrinking motion of the tether-net was demonstrated by comparing the results with those obtained using typical single-linked bullets. Furthermore, the influence of the inner and outer bullet mass ratio on the tether-net deployment and reshrinking motion was numerically analyzed to identify the optimal mass ratio for effectively suppressing the reshrinking motion. The results indicate that a mass ratio of 1.0, or slightly less, between the outer and inner bullets is most effective in suppressing tether-net reshrinking.

Adaptive robust fault-tolerant control of spinning tether system for space debris removal

The Spinning Tether System (STS) is currently recognized as one of the most effective and ideal platforms for removing space debris. It offers several advantages, including a non-contact mechanism, rapid deorbit capabilities, stable spinning, and a short preparation time for subsequent missions. The system primarily depends on the thrusters of the main spacecraft and the capture device for its spin-up process. Although modern technology and quality management methods strive to minimize thruster failures, the capture of debris significantly affects the STS. This impact can induce tether oscillations and cause actuator failures, thereby destabilizing the spin-up process. Given these challenges, this paper explores the design of fault-tolerant control strategies to enhance system reliability during the post-capture spin-up phase. Initially, a dynamic model using quaternions as generalized coordinates was established based on the constrained Lagrange equation. This model facilitated a detailed analysis of potential thruster failure modes. Subsequently, the optimal trajectory for the spin-up process was planned using the pseudo-spectral method, ensuring efficiency and safety in control execution. To address the identified vulnerabilities, the study introduces an adaptive robust fault-tolerant controller. This controller, based on a BLF and integrated with a nonlinear neural network disturbance observer, is designed to operate effectively under fault conditions. Numerical simulations were conducted to validate the performance of the controller, demonstrating its capability to maintain stable control of the system, both after detecting a fault signal and following an actuator failure.

Synergistic Effect of Elliptic Textures and H-DLC Coatings for Enhancing the Tribological Performance of CuAl10Fe5Ni5 Valve Plate Surfaces

Axial piston pumps with compact structures and high efficiency are widely used in construction machinery. The efficiency and lifetime strongly depend on the tribological performance of the pump’s valve plate pair. To enhance the tribological performance of the valve plate pair, surface textures, and H-DLC coatings were fabricated to modify the CuAl10Fe5Ni5 surfaces. The influences of elliptic textures of different sizes and textured H-DLC coatings on the surface friction and wear properties of the valve plate surface under oil lubrication were evaluated using a ring-on-disk tribometer. The results reveal that the friction and wear properties of the CuAl10Fe5Ni5 surfaces are significantly enhanced by elliptic textures, and the friction coefficient and wear rate of textured CuAl10Fe5Ni5 with E90 are maximally decreased by 95% and 87%, respectively. Compared with the surface textures and H-DLC coatings, the textured H-DLC coating has the greatest ability to reduce wear and adhesion. The wear rate of the textured H-DLC coating is further reduced by 98%. This improvement can be explained by the synergistic effect of the elliptic textures and H-DLC coatings, which are attributed to the reduced contact area, debris capture, and secondary lubrication of the elliptic textures, and increased surface hardness.

Implementing Scalable Solutions for Space Debris Mitigation

Abstract: Collision of space debris present in the LEO (Low Earth Orbit) poses a serious threat to the current operational space missions as well as to the future utilization of the LEO space. These also result in major environmental impairment and significant economic losses due to damage to satellites and space stations. It thus becomes imperative to develop effective strategies and design and build systems which can aid in the removal of both small and large debris. This paper investigates the various existing space debris mitigation models such as ElectroDynamic Debris Eliminator (EDDE), ESA’s Space Harpoon, Laser Ablation, and JAXA’s Electrodynamic tether. A useful comparison is drawn amongst these different techniques while evaluating their efficiency within the framework of methods for space debris capture and removal. The advantages and drawbacks of these technologies are discussed through examples, previous and ongoing projects. The paper also aims to briefly introduce a novel concept for debris mitigation and to motivate more rigorous research in this area.

A Trajectory Planning Method for Capture Operation of Space Robotic Arm Based on Deep Reinforcement Learning

Abstract In order to deal with the complex dynamics and control problems involved in space debris removal, a trajectory planning technique for a spatial robotic arm based on twin delayed DDPG (TD3) in deep reinforcement learning is proposed, and it can accomplish an end-to-end control effect comparable to that of human hand gripping objects. The trajectory planning method for capturing space debris by a floating-base space robotic arm is realized using a space robotic arm task simulation platform built on MuJoCo and using trajectory planners, trajectory trackers, and joint and end-effector control strategies formulated with seven different weighted reward functions. This makes it easier to complete spacecraft in-orbit servicing and maintenance missions. The experiment results demonstrate that the capture strategy can maintain a capture success rate of more than 99%, and debris capture can be mostly finished in three stages when taking the stability of the floating base into consideration by continuously modifying the trajectory.

Capture dynamics and driving method of origami capture mechanism in orbit

This article focuses on the dynamic problem of origami capture mechanism capturing space debris in orbit. It delves into the envelope characteristics of the origami capture mechanism, analyzing the motion laws of its axisymmetric folding state. Furthermore, it establishes a kinematic model for the axisymmetric envelope of the origami capture mechanism. A rigid body dynamic model of the origami capture mechanism and a generalized torque equation for the hinge at the crease were established based on the D–H parameter method and the Lagrange method. The enveloping process of the origami capture mechanism in the microgravity environment was simulated using ADAMS software, and the accuracy of the rigid body dynamics model of the origami capture mechanism and the generalized moment equation of the hinge at the crease was verified. Using Ls-Dyna software to simulate the capture process of space debris by force-driven and displacement-driven flexible origami capture mechanisms in microgravity environments, the results show that displacement-driven origami capture mechanisms can quickly capture space debris and are suitable for capturing large-sized space debris; The force-driven origami capture mechanism can quickly complete envelope capture of space debris, suitable for capturing small-sized space debris.

Multi-Debris Capture by Tethered Space Net Robot via Redeployment and Assembly

This paper presents an advanced multiple pieces of debris capture method for the tethered space net robot. A novel capture strategy that integrates redeployment and self-assembly techniques is introduced. With this strategy, the net robot self-assembles to close the net pocket and quickly maneuvers to nearby target debris. Upon reaching its target, the robot redeploys the net for debris capture. Central to this approach is the development of a capturing model that accurately describes the state function of the deployed net and incorporates an effective dragging method to counteract debris bouncing. To enable this multiple pieces of debris capture, an attitude consensus controller and a capture controller are designed using a finite-time scheme and terminal sliding mode, respectively. Numerical simulations reveal limitations in capturing multiple pieces of debris by existing design of tethered space net robots, where debris has the propensity to bounce out of a fully deployed net during multicapture attempts. The proposed strategy effectively mitigates these challenges, minimizing debris bounce and ensuring dependable multiple pieces of debris capture. Overall, the findings offer valuable insights to enhance the efficiency of active space debris removal missions.

A Modified Tip-to-Base LAMPOON to Prevent Left Ventricular Outflow Tract Obstruction in Valve-in-Ring or Valve-in-Valve Transcatheter Mitral Valve Replacement.

The Laceration of the Anterior Mitral leaflet to Prevent Outflow ObtructioN (LAMPOON) procedure may be performed from the leaflet tip to base to prevent left ventricular outflow tract obstruction (LVOTO) in patients with high-risk anatomy undergoing valve-in-valve (VIV) or valve-in-(complete)-ring (VIR) transcatheter mitral valve replacement (TMVR). Thirteen consecutive patients (6 females, average age 67.7 years) with a mean left ventricular ejection fraction of 60%, a median STS score of 3.2%, and degenerative surgical mitral bioprosthesis or ring were treated with a combined, single-stage procedure of preventive LAMPOON and trans-septal TMVR with SAPIEN 3 valves (Edwards Lifesciences, Irvine, CA). Under real-time 3-dimensional transesophageal echocardiography (RT 3D-TEE) guidance, we included the rendezvous technique in the LAMPOON procedure, and all 13 patients were successfully treated by tip-to-base LAMPOON and TMVR. The use of a modified LAMPOON procedure, aided by a rendezvous technique and guided by RT 3D-TEE imaging, offers precise guidance for positioning and aligning the guidewire. This approach not only reduces the need for fluoroscopy and shortens procedure times, but also significantly increases the likelihood of a successful outcome. Importantly, none of the patients in our study experienced unintentional aortic or aortic valve injuries, nor did they develop significant LVOTO following TMVR. In 11 of the 13 (85%) patients, we used a transcatheter SENTINELTM cerebral protection device (Boston Scientific, Marlborough, MA) for stroke prevention and capture of debris ≥ 2 mm were detected in 8/11 (73%) of the cases. Utilizing intra-operative RT 3D-TEE in conjunction with the rendezvous technique can make the tip-to-base LAMPOON procedure even safer and more effective for patients undergoing VIV or VIR TMVR. Our study also suggests that cerebral protection is indicated in patients undergoing TMVR.

Game theory based finite-time formation control using artificial potentials for tethered space net robot

The Tethered Space Net Robot (TSNR) is an innovative solution for active space debris capture and removal. Its large envelope and simple capture method make it an attractive option for this task. However, capturing maneuverable debris with the flexible and elastic underactuated net poses significant challenges. To address this, a novel formation control method for the TSNR is proposed through the integration of differential game theory and robust adaptive control in this paper. Specifically, the trajectory of the TSNR is obtained through the solution of a real-time feedback pursuit-evasion game with a dynamic target, where the primary condition is to ensure the stability of the TSNR. Furthermore, to minimize tracking errors and maintain a specific configuration, a robust adaptive formation control scheme with Artificial Potential Field (APF) based on a Finite-Time Convergent Extended State Observer (FTCESO) is investigated. The proposed control method has a key advantage in suppressing complex oscillations by a new adaptive law, thus precisely maintaining the configuration. Finally, numerical simulations are performed to demonstrate the effectiveness of the proposed scheme.

Deployment dynamics and experiments of a tendon-actuated flexible manipulator

The quantity of space debris on Earth orbit has escalated tremendously in recent years, presenting a significant hazard to human space operations. It is urgent to develop effective measures to capture and remove various space debris. For this purpose, this paper presents a tendon-actuated flexible deployable manipulator. The flexible manipulator consists of several deployable units connected by Cardan joints and actuated by tendons. Compared with the present technologies for capturing space debris such as rigid robotic arm or flying net, this flexible manipulator is deployable, reusable, lightweight and applicable to the capture of large space debris. In order to investigate its deployment dynamics, an accurate dynamic model of the flexible manipulator is established based on the natural coordinate formulation (NCF) and the absolute nodal coordinate formulation (ANCF). Subsequently, numerical simulations are carried out to study the effects of system parameters and the base satellite on its deployment dynamics. Finally, ground experiments for both deployment and bending of the flexible manipulator are conducted to verify its effectiveness and feasibility.

Space Debris Capture - About New Methods of Tethered Space Net Opening by Tubular Booms

Abstract Nowadays, space debris is one of the main subjects of discussion regarding satellites in Earth's orbit. Right now, there are about 26,000 orbiting satellites and only few of these satellites are operational. Recently, the Polish space sector has been strongly growing and delivering instruments working in space. The first part of this paper describes the several space instruments designed in the Space Research Centre Polish Academy of Science (SRC PAS). Instruments such as SWI, RPPWI, LPPWI, Ebox or Pre-boxes have been created for a mission to Jupiter named “JUICE”. After fulfilling their scientific mission, these instruments can increase the amount of debris in space. This is one of the reasons for taking up the topic of space debris reduction and the use of technical solutions used in this mission for the proposed solution presented later. The second part of this paper describes the new methods related to space debris. The activities can be related to the space debris removal programmes. The paper describes two methods developed by Polish scientists used for removal of space debris. One of them is the new capture method and mechanism designed for it. The special mechanism is based on tubular boom application for opening the net, to capture the space debris. The main parts of the mechanism are mechanisms which have been used in the JUICE space mission. The paper describes the main idea for these new methods, and for the design part prepared the strength confirmation by structural analysis. The main function of the mechanism has been verified by simulations and tests performed in laboratories.

Experimental and numerical investigations of damage and ballistic limit velocity of CFRP laminates subject to harpoon impact

The harpoon is a space debris capture mechanism with strong adaptability to targets. In this paper, experiments and finite element models are used to study the harpoon impact on carbon fiber laminate. Firstly, a harpoon penetration gas gun experiment was designed to obtain the damage and ballistic limit velocity of carbon fiber laminates. Then finite element modeling and numerical simulation of the impact on the laminate were carried out using the user–defined VUMAT subroutine in ABAQUS, focusing on the ballistic limit velocity change, damage evolution of the laminate and energy absorption of the laminate when the harpoon penetrates the laminate obliquely at a specific angle. The results showed that compared with vertical penetration, the ballistic limit velocity of harpoon increased by 3.2 %, 9.6 % and 24.3 % respectively under 15°, 30° and 45° oblique penetration conditions; and with the increase of harpoon impact angle, the damage of laminates gradually tended to occur on one side of the projection of harpoon on laminates; while in terms of energy absorption, the energy absorption of laminates for the same angle tended to a constant value as the launch velocity increased.

Prediction and experimental verification of tether net entanglement for space debris capture

Prediction and experimental verification of tether net entanglement for space debris capture

Adaptive Control Scheme for Space Debris Capture in the Presence of Mass and Inertia Uncertainty

Adaptive Control Scheme for Space Debris Capture in the Presence of Mass and Inertia Uncertainty

Performance evaluation of tether-net deployment with adjustable ejection angle

Space debris capture using a tether-net has attracted considerable research attention. To prevent the collapse of the tether-net before debris capture (caused by tension after deployment), various approaches have been proposed, such as the addition of an adhesive material to the tether-net perimeter, use of a net mouth-closing mechanism, or use of a thruster module attached to a weight that controls the weight trajectory after the ejection. However, these mechanisms complicate the net design. To prevent the tether-net collapse prior to debris capture and to ensure its full deployment just before contact with the debris, the tether-net ejection angle must be adjusted in accordance with the distance from the ejector to the debris. In this study, a tether-net ejection mechanism with an adjustable ejection angle is proposed. Moreover, to precisely predict the deployment and bouncing/shrinking behavior of the tether-net, the damping ratio of the net string was determined. Comparison between simulations based on the determined damping ratio and experiments demonstrated good agreement in the maximum deployment area, time to attain the maximum deployment, and the rebound and retraction speeds of the tether-net after complete deployment for large ejection angles. The study findings can contribute to the optimal ejection-angle selection for successful debris capture and prediction of the tether-net behavior after full deployment.

Numerical simulation and behavior prediction of a space net system throughout the capture process: Spread, contact, and close

AbstractIn this paper, we develop an exhaustive numerical simulator for the dynamic visualization and behavior prediction of the tether‐net system during the whole space debris capture phases, including spread, contact, and close. First of all, to perform its geometrically nonlinear deformation, discrete different geometry theory is applied to model the mechanical response of a flexible net. Based on the discretization of the whole structure into multiple vertexes and lines, the internal force and associated Hession are derived in a closed form to solve a series of nonlinear dynamic equations of motion. The spread and deployment of a packaged net can be realized using this well‐established net solver. Next, a multidimensional incremental potential formulation is selected to achieve the intersection‐free boundary nonlinear contact and collision between the deformable net and rigid debris. Finally, for the closing mechanism analysis, a log‐like barrier functional is derived to achieve the nondeviation condition between the ring–rod linkage system. The continuous log barrier functionals constructed for both the contact model and the linkage system are smooth and differentiable, and, therefore, the nonlinear net capture dynamic system can be efficiently solved through a fully implicit time integrator. Overall, as a demonstration, the whole capture process of a defunct satellite using a hexagon net is simulated through our well‐established numerical framework. We believe that our comprehensive numerical methods could provide new insight into the optimal design of active debris removal systems and promote further development of the online control of tether tugging systems.

Biomimicking synovial joints trans-scale structured AgQDs/MXene/SiOC achieving macroscale high lubrication and superior wear resistance

Naturally optimized successful synovial joints with lightweight, high load-carrying, ultra-low friction and wear have attracted tribological communities to constantly imitate and replicate. Despite impressive advances in cartilage lubrication, extending such extraordinary performance advantages to macroscale solid lubrication remains a challenge. Herein, inspired by the fascinating interplay of synovial joints, a novel kind of trans-scale hierarchical structured ceramic-based composite was developed. Introducing microscale Ag microspheres (AgMs) “cartilage” layer and nanoscale Ag quantum dots/MXene (AgQDs/MXene) “synovial fluid” into the interior and exterior of printed macroscale SiOC “hard bone” realistically restores the gradient structure of synovial joint prototype. The resulted composite with ideal compressive strength (70.44 MPa) can achieve a 60.53% friction reduction and a low wear rate (2.05 × 10−6 mm3 N−1 m−1) in dry tribo-contact for 3600 sliding cycles, while also maintaining considerable low friction (∼ 0.11) over 10,000 sliding cycles and long-term stable lubrication (∼ 0.13) for up to 50,000 reciprocating cycles. Such extraordinary performance can be explained by the division of macro contacts, full loading of AgMs and AgQDs/MXene, abrasive debris capture and removal, as well as the shear rolling effect induced by friction process. This work opens a new avenue to develop structural lubricating materials for complex engineering applications.

Validation of Models for Net Deployment and Capture Simulation with Experimental Data

This work validates lumped-parameter models and cable-based models for nets against data from a parabolic flight experiment. The capabilities of a simulator based in Vortex Studio, a multibody dynamics simulation framework, are expanded by introducing i) a lumped-parameter model of the net with lumped masses placed along the threads and ii) a flexible-cable-based model, both of which enable collision detection with thin bodies. An experimental scenario is recreated in simulation, and the deployment and capture phases are analyzed. Good agreement with experiments is observed in both phases, although with differences primarily due to imperfect knowledge of experimental initial conditions. It is demonstrated that both a lumped-parameter model with inner nodes and a cable-based model can enable the detection of collisions between the net and thin geometries of the target. While both models improve notably capture realism compared to a lumped parameter model with no inner nodes, the cable-based model is found to be most computationally efficient. The effect of modeling thread-to-thread collisions (i.e., collisions among parts of the net) is analyzed and determined to be negligible during deployment and initial target wrapping. The results of this work validate the models and increase the confidence in the practicality of this simulator as a tool for research on net-based capture of debris. A cable-based model is validated for the first time in the literature.