Orbital Debris Removal Research Articles

CubeSats for space debris removal from LEO: Prototype design of a robotic arm-based deorbiter CubeSat

Space debris has become a growing problem, and various studies indicate that the population of space objects has reached a critical density in low Earth orbits (LEO). Therefore, removing debris from the LEO is key to stabilizing the growth of space objects and making some of the orbits reusable for future launches. Deorbiting larger debris objects using miniaturized satellites, CubeSats is both economically viable and requires relatively less time for design & deployment. In this paper, we present a system-level study of orbital debris removal from LEO using CubeSats, detailing various existing debris tracking, rendezvous, capture, and deorbit mechanisms. A deep learning-based object detection algorithm has been utilized to improve the accuracy of detecting and localizing debris. We also present a discussion on the CubeSat-compatible capture & deorbit mechanisms identified from our study and an upper bound on the debris mass that can be deorbited from a given LEO orbit using CubeSats. We aim to demonstrate a case study for the orbital decay analysis of a CubeSat deorbiting the XSat, a microsatellite launched by Singapore. We detail the design of a 27U CubeSat deorbiter prototype equipped with a pair of robotic arms to capture the XSat. This analysis considers active deorbiting using Hall-effect thrusters, for which the required delta-V & propellant mass have also been computed.

Multidisciplinary Design Optimization of Active Debris Removal Mission via Electric Propulsion

A design optimization framework for an active orbital debris removal mission to minimize the life cycle cost and mission time is presented. The general concept of operations consists of spacecraft capable of deorbiting 22 identical high-priority debris from sun-synchronous orbit via continuous low thrust from electrostatic thrusters. This modular subsystem framework is proposed and investigated with a fractional factorial design of experiments approach as preliminary analysis in order to inform effects of design variables as well as identify the scope of possible design and output space. The single-objective optimization minimizes the life cycle cost of the mission through a heuristic-based genetic algorithm, resulting in a 4.12-year, $354 million mission using 5.34 kW xenon Hall thrusters. Pareto fronts generated by a multiobjective weighted-sum genetic algorithm are presented to highlight the cost and time objective space for both a nominal and expensive xenon price per kilogram to show design space fluctuations with xenon price volatility. High-power 8 kW xenon Hall thrusters are proven to be in closest proximity to the utopia of the multiobjective design space with a cost of $687 million and mission time of 1 year. High-power krypton Hall thrusters prove to offer a comparable alternative to xenon systems.

Outer Space Exploration and the Sustainability of the Space Environment – An Uneasy Relationship

In contrast with the early years of space flight that were dominated by the political priorities and military concerns of the two superpowers, the USA and the then Soviet Union, a new space era has dawned where not only states are involved as serious actors in the space arena, but also private companies. Because of the significant increase in the number of space actors, outer space is becoming a congested and competitive environment. It is self-evident that the significant increase in private and state-sponsored space ventures has serious implications for the protection and sustainability of the outer space environment. Specifically, the proliferation of space debris and the current lack of protection of vulnerable scientific, historical, and cultural sites on celestial bodies are issues of concern. Several measures to balance the seemingly competing interests of space exploration and the sustainability of the space environment have been suggested. This article aims to discuss these measures and to assess to what extent they are in conformity with the current outer space governance regime. It is concluded that the measures suggested to actively address the space debris problem and to protect the cultural heritage in space may contravene the Outer Space Treaty, especially the rules and prohibitions regarding property rights in space. Moreover, whilst the removal of orbital debris is essential to ensure the sustainable use of the outer space environment, some space junk may have cultural significance and be worthy of protection. A balance should thus be struck between preserving cultural heritage and managing the risks posed by space debris. It is therefore recommended that the development of interim soft-law rules (and an eventual treaty) should be undertaken under the auspices of existing United Nations bodies, namely the UNCOPUOS and UNESCO.

Securing the Space Domain with Active Orbital Debris Removal: Lessons from Europe and Japan Towards a U.S. Strategy

ABSTRACT The proliferation of orbital debris poses a significant threat to spacecraft and satellites in outer space. As the United States currently operates the highest number of satellites in space, its space assets face a heightened risk of orbital debris collision. Mitigation of debris is important, but insufficiently addresses that risk. Debris remediation efforts can supplement mitigation to reduce future collision risks by decreasing the number of large debris, particularly in crowded low Earth Orbit (LEO). After investigating the risks that orbital debris present and current efforts to manage their impact, this paper argues that there is need to implement a national Active Debris Removal (ADR) strategy to protect U.S. space assets and improve the space environment for safe operations. Based on two case studies examining the ADR initiatives of Europe and Japan, we draw four main recommendations for U.S. implementation: (1) commercial initiatives towards ADR capabilities in LEO are promising, (2) government support of an ADR commercial market ensures the latter’s long-term viability, (3) commercial initiatives lower ADR cost and invite innovation, improving the ADR chances of success, and (4) starting with simpler ADR cases reduces U.S. government risk and lowers investment requirements for companies.

Experimental Research on Characteristics of Impulse Coupling and Plasma Plume Generated by Laser Irradiating Copper Target with Nanosecond Pulsed Laser Propulsion

The ejection of the plasma plume produced by laser ablation is an important process for inducing mechanical effects. Therefore, in this paper, the characteristics of the plasma plume are investigated in order to analyze the impulse coupling mechanism with two laser spot diameters, 300 μm and 1100 μm, respectively. The impulse generated by laser irradiating the copper target was measured by the torsion pendulum, and the plasma plume was investigated using fast photography and optical emission spectroscopy. The experimental results show that the optimal laser intensity is independent of the beam spot size. However, when the laser intensity is greater than 2.8 × 109 W/cm2, the impulse coupling coefficient with the small beam spot starts to gradually decrease, while that with the large beam spot tends to saturate. Additionally, the stream-like structure and the semi-ellipsoid structure of the plasma plume were observed, respectively. Furthermore, the electron number density was estimated using the Stark broadening method, and the effect of the plasma plume on the impulse coupling coefficient was discussed. The results provide a technical reference for several applications including orbital debris removal with lasers, laser thrusters, and laser despinning.

Onboard Pointing Error Detection and Estimation of Observation Satellite Data Using Extended Kalman Filter.

The satellite communication is embellished constantly by providing information, ensuring security, and enables the communication among huge at a particular time efficiently. The satellite navigation helps in determining the people's location. Global development, natural disasters, change in climatic conditions, agriculture crop growth, etc., are monitored using satellite observation. Hence, the satellite includes detailed information data, and it must be protected confidentially. The field of the satellite is enhanced at an astonishing pace. Satellite data play an important role in this modern world; hence, the onboard-satellite data must secure through the proper selection of error detection and estimation schema. Lightweight deep learning algorithm based on Extended Kalman Filter (KFK) is proposed to detect and estimate onboard pointing error such as an error in attitude and orbit. The Extended Kalman Filter (EKF) is widely used in the satellite system. EKF is utilized in this proposed model to detect the onboard pointing error such as attitude and orbit determination. An autonomous estimation of orbit position is possible through space-borne gravity. The information obtained through the observation of satellite data is compared with the accurate gravity model in detecting the error. The utilization of EKF reduces the dependence of the ground tracking system in satellite determination. The orbital altitude and orbital position are the most important challenges faced in the satellite determination system. The satellite model using the Extended Kalman Filter is an optimum method in estimating the orbital parameters. The errors in the linearization process are detected, and this can be overcome through the proper selection of linear expansion point with the EKF algorithmic model with the Jacobian matrix calculation. The results show that the EKF implementation helps in attaining better accuracy than other methodologies. Its contribution is enormous to many space missions, autonomous rendezvous and docking for manned and unmanned missions (e.g., ISS operations and beyond, in-orbit servicing, and in-orbit refueling), routine satellite OD operations, orbital debris removal systems, Space Situational Awareness (SSA) operations, and others.

Practical System to Remove Lethal Untracked Orbital Debris

The environment in low Earth orbit (LEO) is congested with orbital debris threatening the safety of all states, actors, and enterprises who wish to use space. Removing orbital debris is unquestionably one of the top space challenges facing space actors of this generation, one that demands cross-disciplinary solutions to solve this complex systems engineering problem. Based on a review of past and recent approaches to active debris removal, many of the currently proposed technologies and systems focus on removing defunct satellites and other large derelict objects in LEO that are actively cataloged and tracked. While removing the larger space objects is a necessary goal, space sustainability experts agree that the orbital debris ranging from 4 mm to 9 cm poses the greatest risk to operational spacecraft and presents unique challenges for its removal. This paper offers a novel technical approach for the development and near-term deployment of an orbital debris removal system based on existing technology that would be capable of reducing lethal untracked orbital debris in LEO.

Development of modelling design tool for harpoon for active space debris removal

The level of debris in Earth orbit presents an increasing risk. Active debris removal, involving capture and deorbit of larger items, has been identified as important in controlling future debris population growth. One concept for capturing debris is a harpoon, with low post-penetration residual velocity being a key design requirement. Aluminium sandwich panels are common structural components on typical spacecraft and consequently a probable target structure. An ideal harpooning event is characterised with complete penetration of the sandwich panel and low harpoon residual (post penetration) velocity. This paper presents development of a numerical modelling tool for a harpoon design for active orbital debris removal. The ability to predict the ballistic limit of an aluminium sandwich panel with a honeycomb core representative of a large satellite structural element being the primary requirement for the modelling tool. The modelling approach was validated against the experimental results from normal and oblique impact tests performed for ogive and flat nose projectiles over a velocity range between 50 m/s to 120 m/s. The modelling was based on explicit finite element method, using the commercial LS-DYNA code. An element failure criterion was used to approximate material damage and failure. Sensitivity studies were performed to investigate the influence of model key features on the projectile exit velocity. The features with the strongest influence were the face sheet material model and the projectile-panel friction model. The projectile exist velocities observed in the experiments were used to select the final parameters used. The use of an element deletion criterion that incorporated the influence of stress triaxiality improved the agreement for the plate deformation behaviour between the numerical and experimental results. For the ogive nose projectile, the exit velocity agreed well with the experiments for the range of impact velocities and angles considered. For the flat nose projectile, the model overestimated the exit velocity. In the case of the normal impact this was due to the model's inability to capture the honeycomb crushing ahead of the projectile.

Space Situational Awareness through Blockchain technology

Kessler Syndrome is a well-known consequence of high-density constellations in Low Earth Orbits (LEO). The rate of satellites being placed in LEO is increasing drastically, whereas the rate of decay of orbital debris is still the same. The current system that predicts collisions is time consuming and complex. At Earth level, it is difficult to maintain everything by a single system, which makes us move towards decentralized systems. This paper explores a self-organizing decentralized network of ground stations and satellites.The current system for tracking satellites and debris, takes a lot of computing power, and does not provide an accurate result. One of those systems, SOCRATES, predicted a close approach of 584 m, between Iridium 33 and Cosmos 2251 [1]. Those two satellites ended up colliding and creating debris. It is discussed how the new proposed system will aid towards the safety of the space tourism and satellite constellations.A collision could be better sensed locally, instead of being predicted by distant systems. Just like blockchains, any information about new objects will spread from the node that detected it. A few types of nodes will exist in the network based on their task priorities. Possibility of “Consensus” utilization between Alpha nodes in the network, is discussed along with crowd sourcing. The Bitcoin or Ethereum, which are based on blockchain consensus, have a delay of about 30 seconds, which includes sharing and processing of the information by almost the whole network. Unlike this, the satellite network will take much less time, as the information is not to be processed by all nodes and it can use broadcasting features over wireless network. Also, all the nodes in the network will not require the whole blockchain in their memory, which will reduce the complexity of the electronics required on the satellites. Potentially, all the new satellites are supposed to carry this small electronic system which can be part of the network if required. Several uses for adding this block, like giving up its location if the orbital debris removal comes into picture, are also discussed. The network will prioritize the information about the current positions of the orbital debris and satellites but will also share the predicted impacts or close pass-by. This data will improve the statistical analysis for the conjunction assessment by making it more accurate and less complex than the current situation.

Validating the Deployment of a Novel Tether Design for Orbital Debris Removal

With the global push to commercialize space, humans are launching objects into orbit faster than natural effects are removing them. Orbital debris is especially dangerous because it is capable of exponential growth due to cascading collisions between orbiting objects. To ensure the long-term accessibility to space, high-risk objects must be actively removed to limit growth of the orbital debris population. One method of active debris removal is with a tethered net to capture and tow an object out of orbit. This work presents the validation of a proposed novel tether configurations deployment dynamics. Tether elements are simulated using two numerical models: a lumped mass node system connected by massless spring–damper elements, and an absolute nodal coordinate formulation model. Their accuracy to predict the deployment motion of a tether is experimentally determined, and a complete capture scenario using the novel tether design is presented for the first time.

An optimized analytical solution for geostationary debris removal using solar sails

Debris in geostationary Earth orbits is often uncontrollable, consisting of launch-vehicle upper stages and non-operational payloads. To help mitigate orbital debris congestion, a solar-sailing satellite concept is proposed which retrieves and relocates large debris for placement into the “graveyard” orbit above the geostationary regime. This work derives an analytical deorbit solution based on Lyapunov control theory combined with the calculus of variations. A dynamic constraint vector is introduced as a result, which dictates the orbital response of a spacecraft to some controlled perturbation. The resulting controller is simulated for various solar sailing platforms to characterize deorbit capability based on a system's area to mass ratio. User design parameters in these solutions are then optimized using a Particle Swarm Optimizer (PSO) to produce robust, locally time optimal solutions for orbital debris removal using solar sails. Solar sail deorbit times are shown to decrease as the reflective area increases, with additional performance dependencies based on the Earth's relative position from the sun.

Directed energy interception of satellites

High power Earth and orbital-based directed energy (DE) systems pose a potential hazard to Earth orbiting spacecraft. The use of very high power, large aperture DE systems to propel spacecraft is being pursued as the only known, feasible method to achieve relativistic flight in our NASA Starlight and Breakthrough Starshot programs. In addition, other beamed power mission scenarios, such as orbital debris removal and our NASA program using DE for powering high performance ion engine missions, pose similar concerns. It is critical to quantify the probability and rates of interception of the DE beam with the approximately 2000 active Earth orbiting spacecraft. We have modeled the interception of the beam with satellites by using their orbital parameters and computing the likelihood of interception for many of the scenarios of the proposed systems we are working on. We are able to simulate both the absolute interception as well as the distance and angle from the beam to the spacecraft, and have modeled a number of scenarios to obtain general probabilities. We have established that the probability of beam interception of any active satellite, including its orbital position uncertainty, during any of the proposed mission scenarios is low (≈10-4). The outcome of this work gives us the ability to predict when to energize the beam without intercept, as well as the capability to turn off the DE as needed for extended mission scenarios. As additional satellites are launched, our work can be readily extended to accommodate them. Our work can also be used to predict interception of astronomical adaptive optics guide-star lasers as well as more general laser use.

XXI century tower: Laser orbital debris removal and collision avoidance

A tall “tower” may have many useful applications in scientific domain: energy production, telecommunications, and entertainment. Sometimes space towers are proposed for an easier access to space such as the Thoth project culminating to an altitude of more than 20 km. Nevertheless, access to space is not the most promising use of a high-altitude tower, among them is the orbital debris removal, major point to keep a safe access to space. Ground based laser has been studied several times, laser on-board of a satellite also (chaser), but never a laser at the top of a tower.Such a solution may combine the advantages of the ground based system (i.e. maintenance, power supply, vast number of debris sightings, versatility) and of the space based system. Nevertheless, building a tall tower is a huge investment and must be profitable, but multiple applications of this tower may be envisaged such to have a good return of investment and so, the others potential utilisation may generate a bulk of revenues. As a driver, this tower supporting a powerful laser can be assimilated to a weapon and so must be kept under international control on the European territory.

Probabilistic Trajectory Optimization Under Uncertain Path Constraints for Close Proximity Operations

Rendezvous and docking operations have been an integral component of manned spaceflight from the beginning of the space age. However, there is now a growing interest in close proximity spacecraft operations in the new areas of orbital debris removal, on-orbit assembly, on-orbit refueling, and on-orbit servicing and repair missions. Current trajectory planning methods focus on performing rendezvous and docking to very well-known targets and in very well-known conditions. Inherent to these new mission types, however, is an increasing element of uncertainty to which new trajectory optimization architectures will need to be robust. There is an inherent tradeoff here between safety and performance. This paper attempts to address the uncertainties underlying path constraints while maintaining a probabilistically optimal level of performance. The goal is to find baseline trajectories with the best expected performance over large uncertainties in mission critical parameters, such as knowledge of an obstacle’s position or attitude of a target spacecraft while knowing that the trajectory is able to be replanned on board the spacecraft when higher-precision information is obtained. Results specific to this problem and the associated analysis motivate the use of this probabilistic planning framework in future space missions.

A deorbiter CubeSat for active orbital debris removal

This paper introduces a mission concept for active removal of orbital debris based on the utilization of the CubeSat form factor. The CubeSat is deployed from a carrier spacecraft, known as a mothership, and is equipped with orbital and attitude control actuators to attach to the target debris, stabilize its attitude, and subsequently move the debris to a lower orbit where atmospheric drag is high enough for the bodies to burn up. The mass and orbit altitude of debris objects that are within the realms of the CubeSat’s propulsion capabilities are identified. The attitude control schemes for the detumbling and deorbiting phases of the mission are specified. The objective of the deorbiting maneuver is to decrease the semi-major axis of the debris orbit, at the fastest rate, from its initial value to a final value of about 6471 km (i.e., 100 km above Earth considering a circular orbit) via a continuous low-thrust orbital transfer. Two case studies are investigated to verify the performance of the deorbiter CubeSat during the detumbling and deorbiting phases of the mission. The baseline target debris used in the study are the decommissioned KOMPSAT-1 satellite and the Pegasus rocket body. The results show that the deorbiting times for the target debris are reduced significantly, from several decades to one or two years.

Low Earth Orbit Debris Removal Technology Assessment Using Genetic Algorithms

On-orbit satellite debris is a growing problem, particularly in several specific regions of low Earth orbit. The continuous growth in the number of objects on orbit increases the likelihood of an ablation cascade, a catastrophic series of collisions initiated by the destruction of a small number of large objects on orbit. Such an event would result in debris clouds that could render many common orbits unusable. Several technologies have been proposed to address the growing debris problem using airborne, ground-based, and space-based systems. This paper evaluates and compares proposed orbital technologies for removing large, intact objects from low Earth orbit, because a collision with one of these objects could produce many small objects. To perform this comparison, software was created to develop designs for debris removal spacecraft. A genetic algorithm was employed to find the most efficient designs for orbital debris removal, with special attention given to minimizing the financial cost of such systems, and the risk they pose to infrastructure and human life in orbit and on the ground. Listings of these Pareto-optimal designs are presented. Propellantless orbital tugs and drag tethers were shown to be competitive with conventional tugs for active debris removal.

A Viable Commercial Model Dealing with Space Debris

The problem of space debris has already been discussed for many years. How to deal with debris and create a viable commercial opportunity for removing debris has become a universal concern nowadays. First of all, our team builds a global fund model that offers a commercial opportunity and assists with orbital debris removal. The fund could be established basing on the simple economic approach to address the problem of space debris. Fund could be collected from any countries involved with the spacecraft launch, prior to all launches for 25 years. Five percentage of the total cost of various space-related missions, which include space activities both in the past and future, are given to the foundation. Approximately half of the payments into the fund would be distributed to those entities devoted in removing space debris, including private firms interested in entering the debris removal market. An attractive market would exist with the policy’s support, assuming that the orbital debris removal could be accomplished with low risk technically. Secondly, the situation about the main countries’ space-related missions is analyzed, and a total cost of each country spent on spaceflight in the past years is estimated. Utilizing the estimated data, the amount of credit that private firm gets from the fund could be derived. At the same time, we create a time-dependent function to predict the budgets for launching satellites in the coming years. Thirdly, the comparison of the different options of removing debris is done and our team chooses the proper methods for cleaning debris objects in varied size according to existed technologies. Right after that the cost taken to do the removal job is derived. Next, the risk is analyzed and the benefit could be predicted. Our model’s dependence on the policy or objective environment makes our result full of uncertainty. Finally, we come to a conclusion that by using our model there would be an economically attractive opportunity for removing space debris with the support of relative policy or international organizations.

Fast, Safe, Propellant-Efficient Spacecraft Motion Planning Under Clohessy–Wiltshire–Hill Dynamics

This paper presents a sampling-based motion planning algorithm for real-time and propellant-optimized autonomous spacecraft trajectory generation in near-circular orbits. Specifically, this paper leverages recent algorithmic advances in the field of robot motion planning to the problem of impulsively actuated, propellant-optimized rendezvous and proximity operations under the Clohessy–Wiltshire–Hill dynamics model. The approach calls upon a modified version of the FMT* algorithm to grow a set of feasible trajectories over a deterministic, low-dispersion set of sample points covering the free state space. To enforce safety, the tree is only grown over the subset of actively safe samples, from which there exists a feasible one-burn collision-avoidance maneuver that can safely circularize the spacecraft orbit along its coasting arc under a given set of potential thruster failures. Key features of the proposed algorithm include 1) theoretical guarantees in terms of trajectory safety and performance, 2) amenability to real-time implementation, and 3) generality, in the sense that a large class of constraints can be handled directly. As a result, the proposed algorithm offers the potential for widespread application, ranging from on-orbit satellite servicing to orbital debris removal and autonomous inspection missions.

天基平台激光清除厘米级空间碎片关键问题探讨

天基平台激光清除厘米级空间碎片关键问题探讨

天基平台激光清除厘米级空间碎片关键问题探讨

天基平台激光清除厘米级空间碎片关键问题探讨