Debris In Earth Orbit Research Articles

Visible Spectral Atlas of Geostationary Satellites from Tucson, AZ for Differentiating Between Natural and Artificial Objects

As near-Earth object (NEO) surveys continue to search for smaller NEOs, they will also detect an increasing number of temporarily captured objects, or minimoons, in geocentric orbital space. Derelict spacecraft and debris in Earth orbit and cislunar space can be mistaken for minimoons, but spectral characterization can distinguish between the two categories of objects. However, systematic noncompositional effects due to nightly and seasonal phase angle changes on artificial objects need to be quantified before such distinctions can be made. These effects have been studied on small solar system bodies, but very little on artificial bodies. We present the reduced data of our multiyear visible wavelength (450–950 nm) spectral campaign of the geostationary Earth-orbiting (GEO) satellite belt from Tucson, AZ, and include comparisons to relevant planetary materials. Although some bus types have steeper spectral slopes than planetary materials, certain bus type spectral features can be confused for planetary materials. One example is a rollover at red wavelengths in the Eurostar-3000 bus-type spectrum that appears similar to mineralogical absorption bands on S- and L-type asteroids. Observations include a total of 96 unique GEO satellites across 192 separate nights from 2020 to 2022. A select subset of GEO satellites is repeatedly observed to measure seasonal variations. Our methods for data acquisition, processing, and cleaning are outlined in this paper. A summary of the atlas shows the full night median spectrum with phase variations and a lightcurve of brightness versus phase angle for each of the 284 sets of data collected.

Penanganan Sampah Satelit Ruang Angkasa Pada Low Earth Orbit Berdasarkan Hukum Internasional

Increased space activity in recent decades has resulted in an increase in the amount of space junk, often referred to as orbital debris. One of the most affected regions is Low Earth Orbit (LEO), where most satellites operate. Satellite debris in Earth orbit, particularly in Low Earth Orbit (LEO), has become an increasingly pressing problem. Its presence can endanger other satellites, space missions and even human life on Earth. The 1967 Space Treaty, as an international agreement governing activities in outer space, has an important role to play in addressing satellite debris. This study analyzes the obligations and responsibilities of states parties in mitigating and addressing the space debris problem in accordance with the basic principles outlined in the Space Treaty. Furthermore, it evaluates the effectiveness of the 1967 Space Treaty in addressing the satellite debris problem. It is recognized that the 1967 Space Treaty has laid an important legal foundation, but a more stringent and comprehensive legal instrument is needed to effectively address this issue. This journal is expected to contribute to the understanding of the international legal framework in handling satellite debris, and encourage the development of stronger legal instruments to preserve the space environment.

Feasibility of using CubeSats and small detectors for in-situ space debris and cosmic dust flux measurement

Impacts on spacecraft by mm-sized debris in Earth orbit can have severe consequences including loss of a spacecraft and generation of more debris. This hazard and potential mitigation are discussed herein, and the risk of an impact (the product of flux and damage) is found vs. size. Reduction of the future flux of mm-sized debris by de-orbiting life-expired space vehicles, only reduces, not eliminates, this hazard. It is thus vital that the flux of mm-sized objects in orbit is well defined, but this requires on-orbit determination. To provide statistically meaningful debris flux data, large detection areas are traditionally required. CubeSats could host debris detectors, but only have small surface areas, and the data from many would be required. Accordingly, flux data from historic small space exposed surfaces are compared herein to MASTER flux model predictions, with good agreement for exposure times of just a few years, demonstrating a viable method to determine the debris flux. The cost of a network of CubeSat mounted impact detectors is also estimated found, and, for fleets of order 100 CubeSats, is comparable to the traditional single large satellite mounted instrument.

Analysis of Imaging Limit Capability for Natural Rendezvous of Low Earth Orbit Debris

Analysis of Imaging Limit Capability for Natural Rendezvous of Low Earth Orbit Debris

Barriers and Gateways to Cleaning Up Earth Orbit: The Legal, Economic, and Political Dimensions of Debris Remediation

The preponderance of human-made debris in Earth orbit has long been recognized as a significant threat to continued safe operations in space. National space agencies and private space companies are paying considerable attention to the technical questions surrounding the active removal of debris (ADR). Nonetheless there are still significant legal, economic, and geopolitical questions that need to be addressed before any meaningful and sustained industry around the removal of debris can be established. This discussion will focus on identifying the legal issues of responsibility, jurisdiction and liability and proposing possible solutions within the current nexus of international agreements. Yet these must be considered alongside the economic roadblocks to funding ADR; the challenges for states looking to collaborate in current geopolitical circumstances; and the often overlooked ‘data deficit’ in respect of the space surveillance and tracking (SST) capabilities needed to enable the safe removal of debris. It is contended that any system for managing ADR, Debris Mitigation and general protection of the space environment should not emerge in isolation. A coherent system of managing and coordinating the orbital environment needs to be developed. This article will argue that it is for individual nations to show political leadership and an economic commitment to properly manage the delicate extraterrestrial environment. Failure to do so will represent a missed opportunity and leave a troubling legacy for future generations. Active Debris Removal, Astropolitics, Space Law, Dual use technology, Space Environment

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.

Adaptive Control of a Tendon-Driven Manipulator for Capturing Non-Cooperative Space Targets

Orbital debris in Earth orbit poses a threat to the future of spaceflight. To combat this issue, this paper proposes a novel robotic mechanism for non-cooperative capture and active servicing missions on non-cooperative targets; specifically, a tendon-driven manipulator is assumed for this work. The capture mechanism is a prototype symmetric two-link gripper driven by an open-ended cable-sheath transmission mechanism. Because the cable-sheath transmission mechanism is a nonlinear time-varying hysteretic system, two separate adaptive control strategies were compared against the uncontrolled and proportional-integral-derivative controlled performance of the closed-loop gripper. Specifically, an indirect control method and a direct controller were employed. Experimental results demonstrate that the adaptive controllers show better tracking performance of a joint trajectory over the proportional-integral-derivative controlled and uncontrolled cases, whereas the controller performs best under dynamic conditions, and the indirect controller performs best in steady state.

Improving Orbital Debris Environment Predictions Through Examining Satellite Movement Data

This paper describes a method for characterizing the 1–3 mm low Earth orbit (LEO) debris environment using satellite perturbation data (unexpected, sudden orbital movements not attributable to other sources), evidenced by changes in Global Positioning System position, temporary breaks in communication links, and other methods. This technique is used to point out a potential overprediction of risk in existing NASA orbital debris models. The paper then proposes a public policy approach for collecting and cataloging this information so that NASA can use the information to update their orbital debris models. Government and private industry can then use the improved debris models to more accurately estimate the 1–3 mm orbital debris population their spacecraft may encounter, develop appropriate debris impact mitigation strategies, improve spacecraft designs, and gain a better understanding for the root causes of potential failures.

A HOLISTIC APPROACH TO THE SPACE DEBRIS MITIGATION

The space activities in almost every orbital regime are now jeopardized by the continuous growth of the space debris populations. To prevent the proliferation of the space debris in Earth orbit it is necessary to tackle the problem from dierent perspectives, exploiting the latest theoretical and experimental knowledge in dierent elds, such as astrodynamics, spacecraft engineering and legal studies, to address four main pillars: prevention, protection, mitigation and regulation. In this respect the European Community nanced a large H2020 project named ReDSHIFT whose goal is to nd passive means to mitigate the proliferation of space debris. A short summary of the project and of its main ndings is given in the paper, with particular emphasis on the more theoretical part, related to the simulation of long term evolutionary scenarios of the whole space debris environment and to the mapping of the Low Earth Orbit phase space, looking for passive dynamical de-orbiting solutions.

Plasma propulsion for telecommunication satellites

Electric thrusters are used for in-space propulsion of spacecraft for a combination of practical and economic reasons. These devices that use electric power to accelerate the mass flow of the propellant at exhaust velocities are one or two order of magnitude faster than those achieved in conventional chemical propulsion. This feature results in significant propellant savings that allows longer mission times and heavier payloads, however, the thrusts achieved are lower for important electric power consumptions. The different electric thrusters that are currently used in Europe for both in-orbit corrections and also for orbit raising to the operational orbit from the separation stage of the launcher will be introduced. This propulsion system also serves to expel these vehicles from their orbit at the end of their useful life to control the increase of space debris in Earth orbit. Additionally, the characteristics of new low-power electric engines with thrust levels in the range 0.1-10 mN and electric power consumptions below 500 W will be discussed. These are required for flight formation, orbital corrections and end-of-life disposal in the new constellations of small satellites in low Earth orbit intended for planetary internet coverage and interactive television services.

An Adaptive Real-Time Detection Algorithm for Dim and Small Photoelectric GSO Debris.

Geosynchronous orbit (GSO) is the ideal orbit for communication, navigation, meteorology and other satellites, but the space of GSO is limited, and there are still a large number of space debris threatening the safety of spacecraft. Therefore, real-time detection of GSO debris is necessary to avoid collision accidents. Because radar is limited by transmitting power and operating distance, it is difficult to detect GSO debris, so photoelectric detection becomes the mainstream way to detect GSO debris. This paper presents an adaptive real-time detection algorithm for GSO debris in the charge coupled device (CCD) images. The main work is as follows: An image adaptive fast registration algorithm and an enhanced dilation difference algorithm are proposed. Combining with mathematical morphology, threshold segmentation and global nearest neighbor (GNN) multi-target tracking algorithm, the functions of image background suppression, registration, suspected target extraction and multi-target tracking are realized. The processing results of a large number of measured data show that the algorithm can detect dim geostationary earth orbit (GEO) and non-GEO debris in GSO belt stably and efficiently, and the processing speed meets the real-time requirements, with strong adaptive ability, and has high practical application value.

A fast algorithm for the detection of faint orbital debris tracks in optical images

Moving objects leave extended tracks in optical images acquired with a telescope that is tracking stars or other targets. By searching images for these tracks, one can obtain statistics on populations of space debris in Earth orbit. The algorithm described here combines matched filtering with a Fourier implementation of the discrete Radon transform and can detect long linear tracks with high sensitivity and speed. Monte-Carlo simulations show that such tracks, in a background of Poisson random noise, can be reliably detected even if they are invisible to the eye. On a 2.2 GHz computer the algorithm can process a 4096×4096-pixel image in less than a minute.

Reconciling space object observed and solar pressure albedo-areas via astrometric and photometric data fusion

There are many Resident Space Objects (RSOs) in the Geostationary Earth Orbit (GEO) regime, both operational and debris. The primary non-gravitational force acting on these RSOs is Solar Radiation Pressure (SRP), which is sensitive to the RSO’s area-to-mass ratio. Sparse observation data and mismodeling of non-gravitational forces has constrained the state of practice in tracking and characterizing RSOs. Accurate identification, characterization, tracking, and motion prediction of RSOs is a high priority research issue as it shall aid in assessing collision probabilities in the GEO regime, and orbital safety writ large. Previous work in characterizing RSOs has taken a preliminary step in exploiting fused astrometric and photometric data to estimate the RSO mass, shape, attitude, and size. This works, in theory, since angles data are sensitive to SRP albedo-area-to-mass ratio, and photometric data are sensitive to shape, attitude, and observed albedo-area. By fusing these two data types, mass and albedo-area both become observable parameters and can be estimated as independent quantities. However, previous work in mass and albedo-area estimation has not quantified and assessed the fundamental physical link between SRP albedo-area and observed albedo-area. The observed albedo-area is always a function of the SRP albedo-area along the line of sight of the observer. This is the physical relationship that this current research exploits. It is shown through simulation that due to this physical link, and through the fusion of astrometric and photometric data, it is possible to observe the mass of a space object when the area is not known. Results for data from 100 trajectories generated from randomly sampled initial conditions are shown. It is seen that even when the area of the object is not known, the uncertainty in mass can be lowered from an initial value of 800 kg to the range 500–700 kg for 72% of the samples, 200–500 kg for 13% of the samples, and 0–200 kg for 15% of the samples. It is further shown that although the uncertainties are large, the actual errors in mass are much lower, with the error RMS being less than 100 kg for 30% of the samples, between 100 and 200 kg for another 30%, and between 200 and 300 kg for 24% of the samples.

A maximal-reward preliminary planning for multi-debris active removal mission in LEO with a greedy heuristic method

An active multi-debris removal mission planning algorithm for low Earth orbit (LEO) debris removal is presented. We assume that a space platform carrying multiple debris-deorbiting nano-satellites will be launched to carry out the debris-removal mission. This platform travels from one debris object to the next using a drift-orbit-transfer strategy. Each debris is assigned a reward value reflecting potential collision risk reductions if the debris is deorbited. The objective of mission planning is to determine an ordering of debris to be deorbited that maximizes the total reward due to debris removal subject to the constraints of (a) the total amount of velocity change for orbit transfer, (b) the total duration of the debris removal mission, and (c) the number of deorbiting nano-satellites carried on board the platform. In this work, a new approach is taken to approximate the response curve of drift-orbit transfers between each debris pair using a numerically interpolated continuous curve. An optimal orbit transfer strategy then is adopted to minimizes the sum of relative Δv consumption and relative transfer duration. The task of multi-debris removal mission planning is formulated as a combinatorial tree search discrete optimization problem using this optimal orbit transfer cost estimate. A greedy heuristic with polynomial time complexity is proposed to select the next debris to deorbit that maximizes the reward-to-cost ratio. The effectiveness of this novel approach is demonstrated using real-world Iridium 33 debris cloud data. It is observed that this algorithm delivers superior performance while consuming a small fraction of computing time compared to state of the art mission planning algorithms.

Assessment of active methods for removal of LEO debris

This paper investigates the applicability of five active methods for removal of large low Earth orbit debris. The removal methods, namely net, laser, electrodynamic tether, ion beam shepherd, and robotic arm, are selected based on a set of high-level space mission constraints. Mission level criteria are then utilized to assess the performance of each redirection method in light of the results obtained from a Monte Carlo simulation. The simulation provides an insight into the removal time, performance robustness, and propellant mass criteria for the targeted debris range. The remaining attributes are quantified based on the models provided in the literature, which take into account several important parameters pertaining to each removal method. The means of assigning attributes to each assessment criterion is discussed in detail. A systematic comparison is performed using two different assessment schemes: Analytical Hierarchy Process and utility-based approach. A third assessment technique, namely the potential-loss analysis, is utilized to highlight the effect of risks in each removal methods.

Post-Newtonian equations of motion for LEO debris objects and space-based acquisition, pointing and tracking laser systems

This paper deals with the problem of throwing middle-sized low Earth orbit debris objects into the atmosphere via laser ablation. The post-Newtonian equations here provided allow (hypothetical) space-based acquisition, pointing and tracking systems endowed with very narrow laser beams to reach the pointing accuracy presently prescribed. In fact, whatever the orbital elements of these objects may be, these equations will allow the operators to account for the corrections needed to balance the deviations of the line of sight directions due to the curvature of the paths the laser beams are to travel along. To minimize the respective corrections, the systems will have to perform initial positioning manoeuvres, and the shooting point-ahead angles will have to be adapted in real time. The enclosed numerical experiments suggest that neglecting these measures will cause fatal errors, due to differences in the actual locations of the objects comparable to their size.

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.

Joint Position Localisation of Spacecraft and Debris for Autonomous Navigation Applications using Angle Measurements only

In this paper, we consider the joint estimation of the position of a spacecraft and debris in Earth orbit to achieve spacecraft localisation based on angular measurements and precise measurements of the debris relative to the spacecraft. The dynamic model of the spacecraft caters for several perturbing effects, such as Earth and Moon gravitational field asymmetry and the Earth's oblateness effect. The Moon's position is assumed to be accurately known for the purposes of simulation from published Jet Propulsion Laboratory (JPL) ephemerides. The measurement process is based on the elevation and azimuth of the Moon and the Sun with respect to the spacecraft reference system. Range measurements are not assumed to be available. Position and velocity of the spacecraft are estimated by using the Unscented Kalman Filter (UKF). The performance of the filters are evaluated on an example of an Earth-orbiting satellite at an altitude over 1200 km with measurements of the directions of the Moon and the Sun only. It is shown that the estimates of position and velocity components track the corresponding simulated position and velocity components.

A new advanced railgun system for debris impact study

Abstract: The growing quantity of debris in Earth orbit poses a danger to users of the orbital environment, such as spacecraft. It also increases the risk that humans or manmade structures could be impacted when objects reenter Earth's atmosphere. During the design of a spacecraft, a requirement may be specified for the surviv-ability of the spacecraft against Meteoroid / Orbital Debris (M/OD) impacts throughout the mission; further-more, the structure of a spacecraft is designed to insure its integrity during the launch and, if it is reusable, during descent, re-entry and landing. In addition, the structure has to provide required stiffness in order to allow for exact positioning of experiments and antennas, and it has to protect the payload against the space environment. In order to decrease the probability of spacecraft failure caused by M/OD, space maneuver is needed to avoid M/OD if the M/OD has dimensions larger than 10cm, but for M/OD with dimensions less than 1cm M/OD shields are needed for spacecrafts. It is therefore necessary to determine the impact-related failure mechanisms and associated ballistic limit equations (BLEs) for typical spacecraft components and subsys-tems. The methods that are used to obtain the ballistic limit equations are numerical simulations and la-borato-ry experiments. In order to perform an high energy ballistic characterization of layered structures, a new ad-vanced electromagnetic accelerator, called railgun, has been assembled and tuned. A railgun is an electrically powered electromagnetic projectile launcher. Such device is made up of a pair of parallel conducting rails, which a sliding metallic armature is accelerated along by the electromagnetic effect (Lorentz force) of a cur-rent that flows down one rail, into the armature and then back along the other rail, thanks to a high power pulse given by a bank of capacitors. A tunable power supplier is used to set the capacitors charging voltage at the desired level: in this way the Rail Gun energy can be tuned as a function of the desired bullet velocity. This facility is able to analyze both low and high velocity impacts. A numerical simulation is also performed by using the Ansys Autodyn code in order to analyze the damage. The experimental results and numerical simulations show that the railgun-device is a good candidate to perform impact testing of materials in the space debris energy range.

A spaceborne, pulsed UV laser system for re-entering or nudging LEO debris, and re-orbiting GEO debris

Among the problems raised by the presence of debris in Earth Orbit, the question of large derelict satellites in Geostationary Orbit (GEO) is of major importance. More than 1000 defunct GEO satellites cruise in the vicinity of this unique orbit and pose the question of orbital slot availability.It is proposed to use lasers in GEO to reorbit the large debris in the graveyard zone, some 300km above GEO. The principle of orbital transfer by laser ablation is recalled, and two different methods are described. These lasers can also serve for small debris deorbiting and large debris nudging in Low Earth Orbit (LEO). Technical details are provided, as well as a preliminary mass budget.