Debris Mitigation Guidelines Research Articles

Effective Compliance to Technical Regulations - Why is Compliance to the Orbital Debris Mitigation Rules So Poor?

Adherence to debris mitigation guidelines is critical for future robust space traffic management (STM). Debris mitigation guidelines are reviewed and their effectiveness at managing the space object population are contrasted against the means to comply with the guidelines. Specific concerns related to the deployment of large constellations are detailed to provide potential trade-offs for consideration in enhanced tracking systems to enable safe and efficient STM practices. The balance between reducing future debris deposition and minimizing the operational burden on satellites to maintain reliable operations are examined.

Probabilistic assessment of disposal orbit lifetime for CubeSat rideshares on resonant decaying geosynchronous transfer orbits

Recent years have seen an increase in CubeSat missions on rideshares to geosynchronous orbit. The typical practice for these missions is to deploy the CubeSat on a geosynchronous transfer orbit (GTO) which results in a perigee altitude that is low enough that atmospheric drag will cause the apogee altitude to decay and eventual reentry. However, for GTOs, demonstrating compliance with limits on orbital lifetime in orbital debris mitigation guidelines is not straightforward due to a solar resonance phenomenon that exists which can cause high variability of the orbital lifetime of the satellite. This paper presents a procedure for determining the likelihood that orbital lifetime of a rideshare CubeSat on a resonant GTO will have an orbital lifetime below a 25-year and 5-year limit. The procedure uses a Monte Carlo analysis in which uncertain parameters are randomly varied, including the launch time/initial RAAN and the drag coefficient. The Aerospace precision propagation tool TRACE is used with a high-fidelity force model to enable precision integration through the atmosphere at perigee. It is shown in the study that there is a systematic variation in likelihood of staying below a 25- and 5-year orbital lifetime limit and that drag enhancement devices may be needed to meet the 5-year limit for CubeSat rideshares. The study also presents findings on a solar radiation pressure induced resonance that was observed for high area-to-mass ratios which suggests that there can be a diminishing return when increasing the area of a drag enhancement device to quicken deorbit.

Post mission disposal of Megha-Tropiques-1 through controlled atmospheric Re-entry to be published in: The journal of space safety engineering

Controlled Re-Entry Experiment of Megha-Tropiques 1 (CREEM), an immensely challenging and significant exercise, was successfully executed on 7 March 2023 by Indian Space Research organization (ISRO) as part of its ongoing efforts to improve compliance with internationally accepted space debris mitigation guidelines. In this paper, we present the overall strategy of CREEM which was primarily shaped by the stringent requirements of targeted impact within a pre-designated zone and ensuring visibility during the final de-boosting burns. We specifically address how the strategy was driven by the on-board and operational constraints, the rationale for the selection of the target region, the de-orbiting maneuver performance details, and the operational workarounds to ensure required subsystem performance. The external coordination related aspects and the lessons learnt are also presented.

Concept and Feasibility Analysis of the Alba Cubesat Mission

AlbaSat is a 2-Unit CubeSat which is being developed by a student team at the University of Padova. The Alba project aims to design, build, test, launch, and operate the first student CubeSat of the University of Padova, featuring four different payloads. The first goal is to collect data regarding the debris environment in Low Earth Orbit, the second goal is the study of the satellite vibrations, the third one is about CubeSat attitude determination through laser ranging technology, and the fourth goal concerns satellite laser and quantum communication. The Alba CubeSat mission has been selected by the European Space Agency to join the Fly Your Satellite! Design Booster program in December 2022. This paper presents the feasibility study of the Alba CubeSat mission reproduced in the framework of the “Space Systems Laboratory” class of Master of Science in Aerospace Engineering at the University of Padova. In the beginning, a mission requirements definition was conducted. After that, the mission feasibility was considered, with preliminary requirements verification to assess the ability of the spacecraft to survive the space environment, including compliance with Debris Mitigation Guidelines, ground station visibility and minimum operative lifetime evaluation. The Alba mission sets a base for a better understanding of the space environment and its interaction with nanosatellites, and an improvement of the accuracy of debris models. Furthermore, this paper, describing the educational experience and the results achieved, will provide a useful example for future students’ studies on CubeSat mission design.

Mission lifetime optimisation with self or assisted disposal

Operation to failure was the modus operandi of most satellite operators prior to the awareness of the impact on the space debris environment. While compliance to space debris mitigation guidelines, standards and regulations is clearly a priority, there remains a business advantage in extracting the maximum lifetime out of any in-orbit asset. For certain types of strategic assets, which provide unique societal benefits through their missions and are typically irreplaceable, due to their complexity, cost and public funding sources, it becomes imperative to ensure extraction of maximum mission value while fully respecting the need for a sustainable orbital environment. With reference to mission examples in EUMETSAT, this paper highlights: the techniques which have already been used to ensure compliant end-of-life strategies while extending mission lifetimes on satellites not designed to support disposal; the approaches made on new generation satellites to achieve compliance with the debris mitigation standards, highlighting what this brings, but also risks remaining for debris mitigation and lifetime value optimisation; how an Active Debris Removal service in LEO positively impacts the lifetime extension/debris mitigation risk trade-off, describing the potential business case for such services on high value, strategic assets.

On a general apogee formula for the disposal of satellites and rocket bodies below the geosynchronous protected region

The geosynchronous orbital region (GEO) is heavily used by satellites. To avoid the proliferation of space debris in this unique orbital environment, space debris mitigation guidelines define a protected region around the orbit and recommend disposal strategies that avoid long-term interference. For satellites operating in the GEO-protected region, a well-known formula was established that defines a minimum-perigee altitude, for a given eccentricity, that avoids drifting back into this regime after the end of the mission. This formula, found in the IADC space debris mitigation guidelines, suggests disposal in near-circular, long-term ‘stable’ orbits above the GEO-protected region, whereby the altitude of perigee is beyond 235 km plus a factor accounting for the solar radiation pressure perturbations. Recently, an extension of this formula that also accounts for the inclination has been suggested. With the advent of direct launch into GEO, whereby either a rocket body or satellite is left in an orbit below the protected region, the natural question arises whether a similar formula can be found for the apogee of disposal orbits below the protected region. The presented work investigates the dynamics of the sub-GEO region and establishes and validates an upper-apogee-difference limit for a time span of at least 100 years. Moreover, the practical implication of such a strategy on the delta-V budget of a mission is assessed.

Study on the Legal Regime for Space Debris Mitigation — Taking the Inter-Agency Space Debris Coordination Committee Space Debris Mitigation Guidelines as an Example

As human space activities continue, the problem of space debris which is regarded as the “killer of satellites, spacecraft, and space shuttles”, remains unresolved. 2021 saw the release of the latest version of the IADC Space Debris Mitigation Guidelines (hereinafter referred to as the IADC Guidelines), the only remediation program to date that has had a significant positive impact on addressing the accumulation of space debris. The IADC Guidelines complement the body of outer space law in the area of space debris and provide a good model for addressing the issue of space debris mitigation. The present paper proposes a path for the future development of the IADC Guidelines to contribute to the improvement of the legal regime for space debris mitigation.

A method of using back propagation neural network to estimate orbital lifetime of LEO satellites

The “IADC space debris mitigation guidelines” requires that the post-mission orbit lifetime of low Earth orbiting (LEO) satellites should not be longer than 25 years, which is the key to debris mitigation. To analyze the degree of global compliance to this 25-year guideline, a fast and relatively accurate orbit life estimation algorithm is required. The traditional method uses numerical orbit propagation to accomplish the task, although its accuracy is high when a high-precision force model is used, the calculation is time-consuming. This paper proposes a new method for orbit lifetime estimation without relying on orbit propagation. A back propagation (BP) neural network is used to directly fit the relationship from the satellite parameters to the orbit lifetime. The space objects that have reentered the Earth’s atmosphere are selected from the catalog database of the US Space Surveillance Network (SSN), and are used to generate samples for network training. The genetic algorithm is combined with the traditional back propagation algorithm for the training of the neural network. The results show that for the specific application background of identifying whether a satellite complies with the 25-year guideline, the orbit lifetime estimation accuracy of the BP network meets the demand to some extent. Moreover, because it does not involve orbit propagation, the BP network has a high computational efficiency in estimating orbit lifetime, showing a good application prospect.

Novel propellant settling strategies for liquid rocket engine restart in microgravity

The active deorbiting and passivation of launch vehicles has become key for the implementation of modern space debris mitigation guidelines. Appropriate engine restart conditions must be provided as part of this process. Ullage motors have been traditionally employed to induce active settling and ensure a gas-free propellant supply to the engines. Although robust and reliable, ullage motors are also heavy, which motivates the study of alternative approaches to the problem. Classic propellant management devices could potentially be employed in this context, but they are hardly applicable to high flow rate cryogenic liquid systems. This paper explores several novel propellant settling strategies that are particularly well suited for cryogenic propellants. In particular, three distinct Magnetic Positive Positioning concepts, a hydrogen-peroxide-based Propellant Gasification System, and a hybrid device that combines both approaches are introduced. The preliminary technical analysis indicates that the successful development of these technologies could lead to mass savings of hundreds of kilograms and economic gains of several hundred thousand dollars per launch.

Improving international governance of space debris in the era of large constellations of small satellites and China’s response

The rapid development of large constellations of small satellites will inevitably lead to a sharp increase of space debris, and thus brings about great threat to space safety and space environment. This poses severe challenges to the current international governance of space debris. The existing space debris mitigation guidelines are neither adaptive nor effective in dealing with the space debris problem in the era of large constellations of small satellites. Under such background, it is indispensable to establish an innovative space debris governance mechanism combining rules both concerning space debris mitigation, prevention, and more importantly, space debris active removal. In this regard, China has been improving its domestic space legislation regarding space debris management at the domestic level. On the other hand, China shall continue to promote the innovative development of space debris governance mechanism at the international level, so as to cope with the conundrums resulting from the development of large constellations of small satellites.

Post-mission de-orbiting of Cartosat-2

India has been voluntarily following the guidelines on space debris mitigation recommended by UN-COPUOS (United Nations Committee on the Peaceful Uses of Outer Space) and IADC (Inter-Agency Space Debris coordination Committee) to the maximum possible extent towards safe and sustainable operations in outer space. As a part of the ongoing efforts for better compliance with these guidelines, post-mission disposal of Low-Earth-Orbit (LEO) objects has been carried out in the recent past. Cartosat-2, which was operational at 630 km altitude, is the first satellite to be de-orbited at its end-of-life through a series of perigee reduction orbit maneuvers to minimize its presence in the LEO region. Consequently, the post-mission orbital lifetime was reduced from more than 30 years to less than 5 years in compliance with the 25-year rule recommended in IADC space debris mitigation guidelines. The de-orbiting exercise utilizing left-over propellant also achieved the objective of minimising any accidental break-up risk. This paper outlines the relevant analyses and planning aspects of post-mission de-orbiting for Cartosat-2. The lessons learnt and recommendations on post-mission disposal for future LEO missions are also presented.

Out of sight, out of mind? The proliferation of space debris and international law

AbstractThe quantity of man-made space objects, ranging from abandoned launch vehicle stages to fragmentation debris, is remarkable. At the time, the drafters of the Outer Space Treaty did not (and perhaps could not) anticipate how great the problem of debris in outer space would one day become. As a result, they only drafted general provisions for the protection of the space environment which are generally deemed insufficient. This article aims to demonstrate that both general rules of international law and the UNCOPUOS Debris Mitigation Guidelines come to the rescue in addressing the space debris issue as they complement and complete the general obligations contained in the Outer Space Treaty. Particular attention is paid to anti-satellite weapon tests, which have catastrophic consequences in terms of creating debris but nonetheless continue to be carried out. Finally, it ascertains whether an obligation on states to actively remove their space debris exists.

초소형위성의 폐기 기동을 위한 항력 증대 장치 개발

In this paper, we described the development of a drag augmentation device for nanosatellite. Recently, space industry has entered the New Space era, and barriers to entry into Low Earth Orbit (LEO) for artificial objects such as small rockets and nanosatellite mega constellations have been significantly lowered. As a result, the number of space debris is increasing exponentially, and it is approaching as a major threat to satellite currently in operation as well as satellites to be launched in near future. To prevent this, international organizations like Inter-Agency Space Debris Coordination Committee (IADC) have been proposed space debris mitigation guidelines. The Korea Aerospace Research Institute (KARI) conducted KARI Rendezvous & Docking demonstration SATellite (KARDSAT) project, the first nanosatellites for rendezvous and docking technology demonstration in Korea, and we also developed drag augmentation device for KARDSAT Target nanosatellite that complied with the international guideline of post-mission disposal.

Drag augmentation systems for space debris mitigation

Space debris is a critical threat to future and on-going missions. The commercialisation of the space sector has led to a rapid growth in the number of small satellites in recent years, which are adding to the already high number of objects currently in low-Earth orbit (LEO). Low-cost small satellites operators are under increasing pressure to comply with debris mitigation guidelines as part of the application process for a launch licence. Drag augmentation systems are a potential low-cost and low-impact solution for small satellites. By increasing the effective area of a satellite, and therefore its drag, these sails reduce the de-orbit period of a satellite, subsequently reducing the probability of significant collisions and supporting the sustainable use of space. Cranfield University are developing a family of drag augmentation systems (DAS) to assist in the long-term conservation of the space environment. The DAS are lightweight, cost-effective, reliable sails deployed at end of mission. Currently three of the drag sails designed, manufactured, and tested at Cranfield University are in orbit and two of the devices have successfully deployed their sails. This paper will discuss these sails and will highlight results from recent studies; examining the scalability of the system, the vehicle dynamics after sail deployment, the medium-term impact of the sail on the host satellite's ability to continue operations, and the long-term effect of the sail on the demisability of the satellite. The DAS technology has a strong enabling potential for future space activities, allowing satellites to operate responsibly and sustainably.

DRAMA 3.0 - Upgrade of ESA’s debris risk assessment and mitigation analysis tool suite

In recent years some countries have established national regulation related to space debris mitigation, while many others are currently considering to follow similar steps. In general, this involves the adoption of already existing and widely accepted standards and international guidelines, such as ISO 24113 or the UN Space Debris Mitigation Guidelines. In order to support the verification of the compliance with existing recommendations, guidelines or even national laws, ESA has been developing the Debris Risk Assessment and Mitigation Analysis (DRAMA) software tool suite. Since 2014, when an ESA instruction came into force rendering space debris mitigation requirements applicable for any ESA satellite mission, DRAMA is being an essential part in mission design and subsequent compliance verification by the Agency. Today more than 1000 users world-wide from industry, academia and agencies are working with the software to address issues such as the remaining orbital lifetime of the spacecraft after disposal or the associated on-ground risk for an uncontrolled re-entry. The recent upgrade to DRAMA 3.0 entails the incorporation of the latest Meteoroid And Space debris Terrestrial Environment Reference (MASTER) model, evolving from MASTER-2009 to MASTER-8; an extensive analysis of Conjunction Data Messages(CDM) which serve as the crucial input to estimate annual collision avoidance manoeuvre rates; a dedicated Python framework to run parametric analyses; and a significant extension of SARA, the tool used for the assessment of on-ground risk upon atmospheric re-entry. The latter includes improvements in the materials database, the aerothermodynamics and aerodynamics as well as an update of the world’s population model. In this paper, the improvements in DRAMA 3.0 are introduced with a focus on showing instructive examples of how the new DRAMA software is being used in the context of verifying compliance with space debris mitigation requirements.

Ionospheric drag for accelerated deorbit from upper low earth orbit

Orbit debris mitigation restrictions placed on the growing number of miniaturised spacecraft often constrain their operational altitudes to less than approximately 600km where drag accelerations are sufficient to deorbit the spacecraft within 25 year guidelines. Operation at higher, Low Earth Orbit (LEO) altitudes often necessitates active measures to deorbit miniaturised spacecraft such as propulsion systems. However, the inclusion of propulsion systems is not always desirable because of the added cost and complexity. This work investigates the feasibility of ionospheric drag, the component of drag caused by an electrically charged body’s exchange of momentum with the ionosphere, to accelerate the deorbit of miniaturised spacecraft in high LEO (600–1000 km altitude). This work studies how actively charging the surface of a miniaturised satellite in high LEO may enhance the overall magnitude of the drag acceleration, due to the ionospheric drag, acting to deorbit the spacecraft. This is achieved using surrogate models of the charged drag coefficient, as a function of plasma scaling parameters, generated by Particle-in-Cell simulations. The charged drag coefficient surrogate model is incorporated into an orbit propagator where deorbit times are predicted over various orbital and vehicular initial conditions. Results suggest that the magnitude of ionospheric drag can be an order of magnitude larger than the neutral drag at 850 km altitude compared to approximately half the magnitude of neutral drag at 500 km altitude. Therefore, ionospheric drag is relatively more efficient at deorbiting spacecraft at high LEO compared to neutral drag. Additionally, the magnitude of ionospheric drag is tailorable based on changes in the electrical surface potential of the satellite relative to a quasi-neutral free-stream plasma. The primary payload of many miniaturised spacecraft often require high-voltage electrical systems. These same electrical systems could conceivably be utilised to generate ionospheric drag via surface charging, at the end of the mission-life, at little additional cost or system complexity. Thus, the implications of this work include the possible uncovering of a simple mechanism for deorbiting miniaturised spacecraft from high LEO altitudes for compliance with orbit debris mitigation guidelines.

Understanding long-term orbital debris population dynamics

Linear growth of the orbital debris population is observed in the results of many evolutionary models when they are used to simulate the effects of the widespread adoption of the Inter-Agency Space Debris Coordination Committee (IADC) debris mitigation guidelines. Such linear growth seemingly confirms the belief that adopting these debris mitigation guidelines will have substantial and positive benefits on the orbital debris population. However, this outcome is not expected from analyses of simple systems models. Either the systems model is too simplistic, or the linear growth of the debris population is actually the beginnings of exponential growth, which is difficult to discern over the typical analysis period. To resolve this ambiguity, the Debris Analysis and Monitoring Architecture to the Geosynchronous Environment (DAMAGE) model was used to perform ultra-long projections of the future debris population ≥ 10 cm in Low Earth Orbit (LEO) under highly optimistic debris mitigation conditions. The DAMAGE results showed that the linear growth rate observed for the first 200 years of the projection period was transient and the growth was exponential, even with the ongoing and widespread adoption of debris mitigation measures. The population growth was driven by the accumulation of orbital debris at altitudes between 1200 km and 1500 km, even though simulated launch activity to that region was limited. Further, the results highlighted a tendency for high and sustained collision rates at altitudes below 700 km, predominantly due to conjunctions between spacecraft and upper stages decaying through this region in observance with the “25-year rule”. Overall, these results indicate that additional, and possibly new, measures to mitigate the effects of orbital debris may be needed, with particular emphasis on post-mission disposal and measures that protect the 1200–1500 km region in LEO.

Performance of EDT system for deorbit devices using new materials

A deorbit device is required for some microsatellites to meet space debris mitigation guidelines, although very challenging in terms of limited resources and reliability. Many groups are conducting research on post-mission disposal (PMD) devices using an electrodynamic tether (EDT) due to its high efficiency and simplicity. Since an EDT for microsatellites must be lightweight, with some strength, high conductivity, high survivability, and meet other requirements, such new materials as carbon nanotube yarn, metal-plated fiber, and metal-deposited thin film are assumed for a tape type tether. In order to determine the appropriate EDT dimensions such as tether width and length, the deorbit capabilities must be evaluated by numerical simulations in advance, as the thrust obtained varies depending on the EDT dimensions, orbital parameters, and other factors. The required resources of the EDT system such as mass and electric power can then be obtained for each orbit, satellite, and deorbit time. Thus, several prototypes of tape type tethers were made and evaluated in various tests.

Application of a debris index for global evaluation of mitigation strategies

The current debris mitigation guidelines are formulated by considering single objects, so they cannot dynamically account for variations in the space traffic, or for the actual current level of implementation and success of post-mission disposal manoeuvres. To address this limitation, the concept of space traffic management based on the environment capacity was proposed. Following this approach, a mission (single or multiple satellites and launch vehicles) is evaluated, before its launch, not only with respect to existing mitigation guidelines, but also with respect to what can be accommodated by the environment (e.g. not exceeding a defined risk level), considering objects already in orbits and other planned future missions. In this way, similarly to the approach used for frequency allocation in GEO, each mission can use a share of the environment capacity through a process that may define, for example, a maximum capacity consumption per year. In order to implement such a scheme, a measure of the debris environment criticality is required. Different formulations for such a metric have been proposed and, in the present work, the ECOB index (Environmental Consequences of Orbital Breakups) is applied. This work will give a brief overview of the most recent changes in the formulation of the index and will discuss examples of applications to the current environment. Different Post-Mission Disposal success rates and future launch traffic scenarios will be analysed. In this context, the evaluation provided by the debris index will be compared to other formulations available in literature and to the one from other indicators such as number of objects and catastrophic collisions. A comparison with operational data from ESA's collision avoidance service will be also presented. Finally, it will be analysed how such an index can be connected to the concept of the environment capacity and a concept for its inclusion within a space traffic management process will be formulated.

Overview of Space Debris Mitigation Activities in ISRO

For several decades orbital debris has been identified as a serious concern by all space-faring agencies and nations as it potentially threatens the current and future space endeavors. The Indian Space Research Organization (ISRO) is well aware of the current space debris scenario and is committed to achieving the goal of preserving outer-space for humanity. ISRO works on different aspects to effectively manage the threats due to space debris. This paper provides an overview of past activities carried out in ISRO towards the implementation of space debris mitigation guidelines. One of the significant step taken is the end of life passivation of the cryogenic upper stage of ISRO’s Geosynchronous Satellite Launch Vehicle (GSLV). Another one is the successful design and development of propellant venting system for the upper stage of ISRO’s Polar Satellite Launch Vehicle (PSLV). ISRO’s constellation of communication satellites orbiting in GSO’s is designed with adequate propellant so that it can re-orbit to the higher graveyard orbit at the end of their operational lifetime. A typical successful re-orbiting and decommissioning operation of INSAT-3E is described in detail here. ISRO has successfully designed and developed the models and software to predict the atmospheric re-entry of satellites and launch vehicle upper stages, also to compute the collision risk between the debris and the operational satellites. ISRO has also developed models to study the evolution of the space debris environment in LEO and GEO. ISRO actively support the efforts of the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS) and Inter-Agency Space Debris Coordination Committee (IADC) to develop and adopt the space debris mitigation guidelines.