Growth Of Space Debris Research Articles

Detecting Moving Objects in Photometric Images Using 3D Hough Transform

In response to the exponential growth of space debris, an increasing number of observation devices are being used for the observation of moving objects, such as space debris and asteroids, which require further improvements in data-processing capabilities for the detection of moving objects. In this study, we propose a rapid detection algorithm designed for detecting moving objects, leveraging the power of the 3D Hough transform. By the simulated image experiments, our results show that the detection rate increases with the number of continuous images when fully extracting objects. Based on this foundation, the object detection rate is at least 87% regardless of the object number in the image sequence when detecting objects from at least six continuous images. In the observed image experiments, we used source-extractor to extract sources. The results show the method can successfully detect objects with signal-to-noise ratio higher than three from sidereal tracking images and can identify asteroids from asteroid tracking images while maintaining a detection speed that meets the requirements for real-time processing.

Hybrid-Compliant System for Soft Capture of Uncooperative Space Debris

Active debris removal (ADR) is positioned by space agencies as an in-orbit task of great importance for stabilizing the exponential growth of space debris. Most of the already developed capturing systems are designed for large specific cooperative satellites, which leads to expensive one-to-one solutions. This paper proposed a versatile hybrid-compliant mechanism to target a vast range of small uncooperative space debris in low Earth orbit (LEO), enabling a profitable one-to-many solution. The system is custom-built to fit into a CubeSat. It incorporates active (with linear actuators and impedance controller) and passive (with revolute joints) compliance to dissipate the impact energy, ensure sufficient contact time, and successfully help capture a broader range of space debris. A simulation study was conducted to evaluate and validate the necessity of integrating hybrid compliance into the ADR system. This study found the relationships among the debris mass, the system’s stiffness, and the contact time and provided the required data for tuning the impedance controller (IC) gains. This study also demonstrated the importance of hybrid compliance to guarantee the safe and reliable capture of a broader range of space debris.

Dossier: Eduardo Kac’sAdsum, Artwork for the Moon

Dossier: Eduardo Kac’s<i>Adsum</i>, Artwork for the Moon

Impact resistance mechanism of reactive material bumper for spacecraft Whipple shield: Experiments and numerical simulations

With the rapid development of human manned spaceflight, the threat of hypervelocity impact of space debris to spacecraft safety has attracted more and more attention, and new materials for spacecraft shield need to be developed to meet the challenges caused by explosive growth of space debris. In this paper, the experiments of projectiles with hypervelocity impact on the Whipple shields with reactive material as bumpers were carried out by using two-stage light-gas gun. Through numerical simulations and experiments, the interaction between projectile and reactive material bumper was studied, and the fragments distribution, velocity and temperature of debris cloud induced by projectile impacting on reactive material bumper were analyzed. The hypervelocity impact resistance mechanism of Whipple shield with reactive material as bumper was obtained. The results show that the impact and detonation reaction combined effect of reactive material bumper can cause the projectile to be subjected to shock wave load twice, which leads to more effective fragmentation of projectile, more effective dispersion and deceleration of debris cloud, and more effective temperature rise of material. Reactive material bumper can improve the protective capability of Whipple shield, and has a great potential application prospect.

Management of Celestial Systems under Spatial Grasp Model

Many governmental agencies and private companies of different countries are now rushing into space around Earth in hope to provide smart communication, industrial, security, and defense solutions. This often involves massive launches of cheap small satellites which are also contributing to the growth of space debris. The current paper discusses how the developed high-level system philosophy and model can effectively organize distributed space-based systems on different stages of their development and growth. The briefed Spatial Grasp Technology, based on parallel pattern-matching of distributed environments with high-level recursive mobile code, can effectively provide any networking protocols and important applications of large satellite constellations, especially those on Low Earth Orbits. The paper contains examples of technology-based solutions for establishing basic communications between satellites, starting from their initial, often chaotic, launches and distributing and collecting data in the growing constellations with even unstable and rapidly changing connections between satellites. It describes how to organize and register networking topologies in case of predictable distances between satellites, and how the fixed networking structures can help in solving complex problems. The latter including those related to the new Space Development Agency multiple-satellite defense-oriented architecture and allowing for effective integration of its continuous earth custody observation and cooperative missile tracking and elimination layers, based on self-spreading mobile intelligence. Earlier versions of the technology, described in many papers, six books including, were prototyped and used in different countries, with the current one quickly implementable too, even in university-based environments.

Tuning of NASA Standard Breakup Model for Fragmentation Events Modelling

The continuous growth of space debris motivates the development and the improvement of tools that support the monitoring of a more and more congested space environment. Satellite breakup models play a key role to predict and analyze orbital debris evolution, and the NASA Standard Breakup Model represents a widely used reference, with current activities relevant to its evolution and improvements especially towards fragmentation of small mass spacecraft. From an operational perspective, an important point for fragmentation modelling concerns the tuning of the breakup model to achieve consistency with orbital data of observed fragments. In this framework, this paper proposes an iterative approach to estimate the model inputs, and in particular, the parents’ masses involved in a collision event. The iterative logic exploits the knowledge of Two Line Elements (TLE) of the fragments at some time after the event to adjust the input parameters of the breakup model with the objective of obtaining the same number of real fragments within a certain tolerance. Atmospheric re-entry is accounted for. As a result, the breakup model outputs a set of fragments whose statistical distribution, in terms of number and size, is consistent with the catalogued ones. The iterative approach is demonstrated for two different scenarios (i.e., catastrophic collision and non-catastrophic collision) using numerical simulations. Then, it is also applied to a real collision event.

Development of space-based distributed systems under spatial grasp technology.

Many governmental agencies and private companies of different countries are now rushing into space around Earth in the hope to provide smart communication, industrial, security and defense solutions. This often involves massive launches of small cheap satellites which are also contributing to the growth of space debris. The current paper discusses how the developed high-level system philosophy and model can effectively organize distributed space-based systems on different stages of their development and growth. The briefed Spatial Grasp Technology, based on parallel pattern-matching of distributed environments with high-level recursive mobile code, can effectively provide any networking protocols and important applications of large satellite constellations, especially those in low Earth orbits. The article gives some examples of technology-based solutions for establishing basic communications between satellites, starting from their initial, often chaotic, launches and distributing and collecting data in the growing constellations with even unstable and rapidly changing connections between satellites. It describes how to organize and register networking topologies in case of predictable distances between satellites, and how the fixed networking structures can help in solving complex problems. The latter includes those related to the new Space Development Agency’s multiple-satellite defense-oriented architecture and allows for effective integration of its continuous Earth custody observation and cooperative missile tracking and elimination layers, based on self-spreading mobile intelligence. Earlier versions of the technology, described in many papers, six books including, were prototyped and used in different countries, with the current one quickly implementable too, even in university-based environments.

Trajectory planning and coordination control of a space robot for detumbling a flexible tumbling target in post-capture phase

The rapid growth of space debris poses a serious threat to space exploration activities. Large space debris, such as malfunctioning satellites, are generally uncooperative tumbling objects with flexible appendages. This paper investigates the detumbling scheme for a flexible target using a flexible-base space robot in post-capture phase. This scheme consists of trajectory planning and coordination control, which can bring the target to rest and stabilize the base attitude of the space robot while suppressing the vibrations of the flexible panels. In this paper, a recursive method based on the Newton–Euler formulation is employed to derive the kinematics and dynamics of the combined system. The trajectory planning of the end-effector is converted to a constrained multiobjective optimization problem, whose Pareto front is obtained by the multiobjective particle swarm optimization (MOPSO) algorithm. A coordination controller is developed to track the planned trajectories of the space robot. The presented numerical simulations verify the effectiveness of the detumbling scheme and its robustness to space targets with parametric uncertainties.

Numerical Simulation of Vacuum Leak Jet and Jet Noise

With the explosive growth of space debris, collisions among space debris and spacecrafts seem to be inevitable, which may greatly threaten the structure of on-orbit spacecrafts as well as astronauts’ safety. It is of crucial importance to locate the leak source and evaluate the corresponding damage quickly and accurately to ensure the safety of astronauts and spacecraft equipment. It is widely accepted that acoustic emission method can be used to detect on-orbit leak for space station; however, accurate prediction of vacuum leak noise in space station is difficult as jet and jet noise in vacuum environments are different from those in terrestrial environment. Therefore, this paper tries to investigate sound generations of vacuum leak jet by numerically analyzing dynamics of unsteady vacuum jet flow. Specifically, numerical simulation based on realizable k-ε model is adopted to study the aerodynamic properties and the aeroacoustic characteristics. Results show that RANS turbulent model can capture the pressure fluctuation with high computation efficiency and acceptable accuracy. Secondly, leak from 1 atm to vacuum forms a supersonic flow with Mach number ranging from 2 to 3, accompanied by obvious gradients of steady density, pressure, and temperature. However, the terrestrial leak from 2 atm to 1 atm forms subsonic jet flow with gradually varying gradients of density, pressure, and temperature. Thirdly, obvious reflections of pressure perturbations at the surface, with the mean free path of air molecule being 0.6 mm, can be found and form cavity-like acoustic resonance. Such resonant mechanism contributes to harmonic acoustic properties of the vacuum jet noises besides the broadband turbulent mixing noises.

Simulation and tension control of a tether-actuated closing mechanism for net-based capture of space debris

The growth of space debris in Earth's orbit is recognized as a serious threat to future space missions. To contain the growth of space debris in the long term, active removal of large defunct spacecraft is needed. A promising solution to this problem is the use of tether-nets. In the envisaged mission, a net is released from a chaser spacecraft toward a target debris; the net entangles the debris and the tether provides a flexible link between chaser and debris to tug the debris to a disposal orbit. The present work is focused on the simulation and control of a tether-actuated closing mechanism. In this concept, proposed only recently, the tether is looped through the center of the net and around the perimeter, and spooling the tether in draws the net perimeter closed. In this paper, a dynamic model of a tether-actuated closing mechanism for net-based capture of space debris is developed. The model of the winch, which is key to the control of the closing mechanism, is established based on literature on the design of reeling mechanisms for tether-nets. Two control laws for the winch velocity during deployment and closure of the net, respectively, are formulated and tested in simulation. Simulations of the capture of a Zenit-2 rocket upper stage are performed using a proportional-derivative tension control law with gain scheduling based on tether length. Results support feasibility of the tether-actuated closing mechanism.

Chinese perspective on an international regime of space traffic management

In recent decades, the outer space environment has become increasingly congested as a result of the proliferation of space activity, the growth of space debris, and the diversification of parties entering space. This has caused serious threats to the safety of space activity and operations. Space traffic management (STM) is an effective way of monitoring space traffic, protecting the space environment, and securing space safety. The establishment of an international STM regime requires sufficient technical capacity, and more importantly, effective regulatory arrangements at both the domestic and international levels.This paper aims to examine China's domestic legal and policy arrangements, its efforts and practice at the international level, and underlying concerns regarding STM. In this regard, China has established several departmental rules governing regulatory management, such as the registration of space objects and the acquisition of permits for civil space launch projects. As to the remediation of space debris, the recently issued Interim Measures on Space Debris Mitigation and Protective Management deals with the problem of space debris from various aspects including R&D, launch, operation of space vehicles, evaluation of collision risk and coping measures. In general, China has realized the importance of implementing STM and has made certain legal and policy arrangements in this regard. However, due to the diverse perspectives and interests of countries, as well as the sensitivity involved with STM, the establishment of an international STM regime would not be possible without effective cooperation and interest coordination among space-faring countries. At the domestic level, China would still need to improve its space legislation and ensure the effective implementation of relevant rules and policies; at the international level, China would continue to promote international cooperation, particularly, space data sharing, participation in related international space legislation, and facilitation of the establishment of an international regime of STM.

Contact Dynamics Modeling and Simulation of Tether Nets for Space-Debris Capture

A proposed method for containing the growth of space debris, which jeopardizes operation of spacecraft, is the active debris removal of massive derelict spacecraft and launcher upper stages by means of tether nets. The behavior of nets in space is not well known; therefore, numerical simulation is needed to gain understanding of deployment and capture dynamics. In this paper, a lumped-parameter approach for modeling the net and different models of contact dynamics are presented. A continuous compliant approach for the normal contact force and a modified damped bristle model for the friction force are chosen. The capability of the developed simulation tool to represent multiple dynamic conditions is demonstrated in this paper, and the results of a deployment dynamics simulation are presented; this reveals a snapping behavior of tension. Simulation of net-based capture of cylindrical debris in microgravity and vacuum conditions is performed with the presented tool. The effect of employing different contact force models on the overall results of capture is evaluated, both from a dynamical and a computational point of view, and reasons to prefer nonlinear models are discussed.

Nonlinear dynamics and coupling effect of libration and vibration of tethered space robot in deorbiting process

In order to control the growth of space debris, a novel tethered space robot (TSR) was put forward. After capture,the platform, tether, and target constituted a tethered combination system. General nonlinear dynamics of the tethered combination system in the post-capture phase was established with the consideration of the attitudes of two spacecrafts and the quadratic nonlinear elasticity of the tether. The motion law of the tethered combination in the deorbiting process with different disturbances was simulated and discussed on the premise that the platform was only controlled by a constant thrust force. It is known that the four motion freedoms of the tethered combination are coupled with each other in the deorbiting process from the simulation results. A noticeable phenomenon is that the tether longitudinal vibration does not decay to vanish even under the large tether damping with initial attitude disturbances due to the coupling effect. The approximate analytical solutions of the dynamics for a simplified model are obtained through the perturbation method. The condition of the inter resonance phenomenon is the frequency ratio λ1=2. The case study shows good accordance between the analytical solutions and numerical results, indicating the effectiveness and correctness of approximate analytical solutions.

Active debris removal GNC challenges over design and required ground validation

Because of the exponential growth of space debris, the access to space in the medium-term future is considered as being seriously compromised, particularly within LEO polar Sun-synchronous orbits and within geostationary orbits. The active debris removal (ADR) application poses new and challenging requirements on: first, the new required Guidance, Navigation and Control (GNC) technologies and, second, how to validate these new technologies before being applied in real missions. There is no doubt about the strong safety and collision risk aspects affecting the real operational ADR missions. But it shall be considered that even ADR demonstration missions will be affected by significant risk of collision during the demonstration, and that the ADR GNC systems/technologies to be used shall be well mature before using/demonstrating them in space. Specific and dedicated on-ground validation approaches, techniques and facilities are mandatory. The different ADR techniques can be roughly catalogued in three main groups (rigid capture, non-rigid capture and contactless). All of them have a strong impact on the GNC system of the active vehicle during the capture/proximity phase and, particularly, during the active vehicle/debris combo control phase after capture and during the de-orbiting phase. The main operational phases on an ADR scenario are: (1) ground controlled phase (ADR vehicle and debris are far), (2) fine orbit synchronization phase (ADR vehicle to reach debris ±V-bar), (3) short range phase (along track distance reduction till 10–100 s of metres), (4) terminal approach/capture phase and (5) de-orbiting. While phases 1–3 are somehow conventional and already addressed in detail during past/on-going studies related to rendezvous and/or formation flying, phases 4–5 are very specific and not mature in terms of GNC needed technologies and HW equipment. GMV is currently performing different internal activities and ESA studies/developments related to ADR mission, GNC and capture technologies. This paper focuses on some specific aspects and technologies related to ADR terminal phases involved technologies and ground validation approaches: (1) Terminal ADR approach phase using visual-based navigation (VBN). Potential Image Processing techniques and preliminary performances will be described, together with the challenge of generating on-ground realistic images as input for the HW/SW VBN system. Some results of image generation (including comparison with real flight image missions) and processing using GMV’s Optical Laboratory (image generation by rendering spacecraft 3D models and projecting on a screen in front of the HW camera) and using GMV’s platform-art ® laboratory to reproduce space-realistic physical scenarios (to be captured by a HW camera) using 1:1 physical spacecraft mock-ups in an absolutely dark environment with a Sun-like single illumination source. (2) Ground validation of GNC systems based on HW-in-the-Loop (HIL) test facilities, including realistic space-representative avionics (at processor, interfaces and real-time operating system), realistic and air-to-air stimulated breadboard perception sensors (IMU, optical cameras, laser 3D sensors) through the use of dynamic robotic devices hosting the active vehicle and debris mock-ups and reproducing accurately the spatial relative dynamic corresponding to an ADR scenario. This type of ground validation can effectively achieve validation in relevant environment, till TRL (Technology Readiness Level) 5/6 on ground and minimizing the uncertainty/risk of such technologies/systems with respect to its operational use. Description and video demonstration of some ADR applicable test case/s using GMV’s platform-art ® dynamic test facility will be included. Particular attention will be paid on the needed type of structural/functional active ADR vehicle and debris mock-ups, force/torque measurement and feedback capability over debris contact or momentum exchange actions, ground gravity compensation.

Dynamics of tether-tugging reorbiting with net capture

To control the growth of space debris in the geostationary earth orbit (GEO), a novel solution of net capture and tether-tugging reorbiting is proposed. After capture, the tug (i.e., active spacecraft), tether, net, and target (i.e., GEO debris) constitute a rigid-flexible coupled tethered combination system (TCS), and subsequently the system is transported to the graveyard orbit by a thruster equipped on the tug. This paper attempts to study the dynamics of tether-tugging reorbiting after net capture. The net is equivalent to four flexible bridles, and the tug and target are viewed as rigid bodies. A sophisticated mathematical model is developed, taking into account the system orbital motion, relative motion of two spacecraft and spacecraft attitude motion. Given the complexity of the model, the numerical method is adopted to study the system dynamics characteristics. Particular attention is given to the investigation of the possible risks such as tether slack, spacecraft collision, tether rupture, tether-tug intertwist and destabilizing of the tug’s attitude. The influence of the initial conditions and the magnitudes of the thrust are studied.

Space Debris Removal Strategies and their Feasibility

The need for debris mitigation is illustrated in the context of historic launch activates and operational practices. This has led to the existing space debris environment, with consequent collision flux levels that are based on detailed population and evolution models. Therefore mitigation of space debris has become a major concern for us humans lately. National space agencies have proposed many space debris mitigation measures to reduce and stabilize the predicted long term growth of space object population. Through this article we take a closer look at the mathematical analysis of three main strategies adapted to reduce and stabilize the growth of space debris.

Space Debris Removal Strategies and their Feasibility

The need for debris mitigation is illustrated in the context of historic launch activates and operational practices. This has led to the existing space debris environment, with consequent collision flux levels that are based on detailed population and evolution models. Therefore mitigation of space debris has become a major concern for us humans lately. National space agencies have proposed many space debris mitigation measures to reduce and stabilize the predicted long term growth of space object population. Through this article we take a closer look at the mathematical analysis of three main strategies adapted to reduce and stabilize the growth of space debris.

A brief scenario about the "space pollution" around the Earth

In this work is presented a brief review about the main events generating of space debris around the Earth, occurred up to the present day. How the clouds of debris "polluted" the neighborhood of orbits in which the bodies were initially allocated is here analyzed. The implications of the growth of space debris existing on space missions as well as safety rules to control sources of debris are discussed.

Deployment of an Electrodynamic Tether from a Small Satellite

As an effective countermeasure for suppressing space debris growth, the Aerospace Research and Development Directorate, Japan Aerospace Exploration Agency (JAXA) has been investigating an active space debris removal system that employs highly-efficient electrodynamic tether (EDT) technology as its orbital transfer system. A test flight experiment using a small satellite is planned for establishing and demonstrating the EDT technology. Precise tether dynamics during deployment phase is investigated in this study by numerical simulations in which the coiling of the tether is taken into consideration. The results of the simulation showed that the tether length becomes shorter than the full tether length when the coiling of the tether is severe. The in-plane libration angle of the tether grows larger when the spring constant of the coiling of the tether is specific value. The attitude motion of a mother satellite is less stable when the spring constant of the coiling of the tether is small because of the large tether tension.

Precise numerical simulations of electrodynamic tethers for an active debris removal system

As a countermeasure for suppressing space debris growth, the Institute of Space Technology and Aeronautics, Japan Aerospace Exploration Agency (JAXA), is investigating an active space debris removal system that employs highly efficient electrodynamic tether (EDT) technology as its orbital transfer system. A small, expendable EDT package is under development that consists of a bare conductive tether and field emitter cathodes (FECs) that utilize carbon nanotubes. First, the status of the trial manufacture of the bare tether, reel mechanism, and the FECs are described. Some tests for example for measuring tensile strength and thermal expansion have been conducted on the tether. Next, precise numerical simulations are performed for some aspects of mission analysis, such as available electric currents, orbital changes, tether stability, and deployment dynamics. A tether is modeled as a lumped mass to take into account tether flexibility, and environment models (changes in the plasma density and geomagnetic field, and so on) are also considered. Measured parameters of the manufactured tether described above are reflected in the numerical simulations. Differences between the precise and simple models are compared and discussed.