Space Debris Reentry Research Articles

Detection of fireballs in the Lightning Imager data

ABSTRACT The Meteosat Third Generation - Imager 1 satellite, launched on 13 December 2022, features the first Lightning Imager instrument, a high-speed optical camera providing near real-time lightning detection over Europe and Africa. This study demonstrates that signatures of fireballs (i.e. bright meteors) can be detected in Lightning Imager data. We describe a method to analyse this data to determine the timing, light signal, and trajectory of fireballs, highlighting the instrument’s usefulness for bright meteor observation and proposing avenues for further research. By using known fireball locations and timings from external sources, the Lightning Imager data can be filtered to isolate ‘lightning events’ induced by the meteor. From this data set, the fireball light curve is computed by aggregating signal increases measured by instrument pixels. A trajectory is then deduced using a weighted average of pixel locations based on observed intensity. Three examples of fireballs detected by the Lightning Imager are presented, including a man-made meteor from space debris re-entry, with estimated timing, light curves, and trajectories.

The pioneer Cluster mission: preparation of its legacy phase near re-entry

The Cluster mission will always be the first ever multi-spacecraft mission mapping the Earth magnetosphere in three dimensions. Launched in 2000 and originally planned to operate for two years, it has been orbiting Earth for more than two solar cycles. Over the course of its lifetime, its data have enabled the scientific community to conduct pioneer science. Recent scientific highlights will be presented first, followed by the latest scientific objectives that have guided the Cluster mission operations from 2021 until 2024. Early September 2024, one spacecraft of this veteran constellation will re-enter in a controlled manner the Earth’s atmosphere, followed by its companions in 2025 and 2026. As we will see, this will be a unique opportunity to improve the ESA space debris re-entry models. Lastly, preparation of its legacy phase will be presented.Graphical

Assessing the Risk of Uncontrolled Space Debris Re-entry: A Case for Airspace Management and Flight Safety

We explore the risks associated with uncontrolled space debris re-entry and the implications for airspace management and flight safety. With the increasing number of satellites and other objects being launched into space the potential for uncontrolled re-entry events poses a unique challenge for airspace management and public safety. While there have been no recorded instances of aircraft damage or human injury due to re-entering space debris, the increasing frequency of such events necessitates a comprehensive understanding of the associated risks and appropriate mitigation strategies. We briefly examine the current methods for tracking and predicting space debris re-entry, concentrating on the decision-making process for airspace closures, and the risk assessment for ground airborne safety. Our analysis aims to contribute to the ongoing dialogue on space debris management and to inform future policy and operational decisions in the context of civil aviation and public safety.

Numerical Simulation Of A Bi-directional Plasma Thruster For Space Debris Removal

A spacecraft during mission typically switches from chemical propulsion to electric propulsion once it lifts out of the Earth's gravity as the thrust requirement to drive it reduces substantially. Consequently, electric propulsion technology is commonly used for deep space mission, satellite orbit keeping and orbit correction. In the last few decades, the amount of man-made space junk (space debris) has increased enormously and has become a potential danger for space stations, space shuttles and other live satellites. A bi-directional plasma thruster, mounted on a satellite, can be used to remove space debris during satellite operation (Takahashi et al., Sci. Rep., vol. 8, 2018, p. 14417). A directed ion beam ejected from a plasma thruster imparts a net force on space debris to decelerate and facilitates manoeuvring and re-entry of space debris into the Earth's atmosphere where it can burn out. We present a detailed 1D3V PIC-MCC (particle in cell-Monte Carlo collision) simulation of a bi- directional plasma thruster. To this end, a PIC-MCC solver which resolves thruster axial direction and all three velocity dimensions is used to study a magnetic nozzle plasma thruster with both ends open (bi-directional plasma thruster). We show that such a bi-directional plasma thruster can be used to accelerate–decelerate a live satellite and also to remove space debris by altering the magnetic field spatial profile in the plasma expansion region. A detailed study is presented.

Study of the degradation of epoxy resins used in spacecraft components by thermogravimetry and fast pyrolysis

Predicting the demisability upon re-entry of space debris objects is of great importance due to the threat these objects pose if they were to fall in an inhabited area. In particular, carbon/epoxy composite materials have been found on Earth in several occasions. Accurate models to assess the demisability of such components require, in particular, detailed thermal degradation data for the epoxy resin. In this work, we analyze a resin used to manufacture such components, using thermogravimetric analysis (TGA), organic elemental analysis, and pyrolysis coupled to comprehensive two-dimensional gas chromatography. The epoxy resin rapidly decomposed in a relatively narrow range of temperatures (300–400∘C) in more than 70 different volatile products. A one-step kinetic model is proposed for the pyrolysis of epoxy based on thermogravimetry observations. The information on the species and elemental composition can be used to develop more accurate material degradation models for predicting the demisability upon re-entry of space debris.

Aerodynamic forces of interacting spheres representative of space debris re-entry: Experiments in a supersonic rarefied wind-tunnel

Experimental investigations of two interacting spheres were carried out in a Mach 4 flow with a static pressure of 2.666 Pa. This study was performed in the MARHy wind tunnel, an adjustable supersonic or hypersonic low-density facility. The main purpose is to estimate how the interactions between spherical debris modify the aerodynamic forces during their atmospheric entry. Indeed, around 80 km, altitude experimentally reproduced thanks to MARHy flow conditions, most debris fragment. The multiple debris, resulting from fragmentation, interact with each other’s, which may impact their trajectory. The purpose of this work is to analyze the behavior of a moving sphere placed in the wake of another one. The moving sphere is suspended with two thin wires, so it can almost freely move in the flow direction and physically respond to the acting flow forces of the wake of the first one. Aerodynamic forces are then calculated from the sphere angle deflection. The qualitative analysis of the experimental results will be discriminated first with respect to the trajectory of the second sphere, and secondly with respect to the evolution of the aerodynamic forces according to the sphere.

Reentry of Space Debris from Low Earth Orbit by Pulsed Nd:YAG Laser

This research studies the orbital dynamics of space debris in near-earth orbit and calculates its respective lifetime. The orbital dynamics of space debris is closely examined in near-earth orbit whereby (apogee altitude ha=1200 km and perigee altitude hp=200 km). In addition, the lifetime of the space debris is calculated using the influence of the friction force exerted on the atmospheric particles with debris dimensions measuring between (1-10 cm). In this study, the Drag Thermospheric Models (DTM78 and DTM94) are used because of their dependence on solar and geomagnetic activities, and pulsed lasers are utilized to interact with Aluminum 2024 particles which are frequently employed in the structure of spacecraft and aerospace designs. A numerical analysis program (NaP1) was built to calculate the lifetime of space debris and its time of return to the atmosphere. It is then integrated with a second numerical analysis program (NaP2) developed using the Lax-Wendroff finite difference method to simulate the laser material interaction model. A high-power Nd:YAG laser was applied to produce shock wave pressure in the target. The results show that the maximum peak pressure occurs at 50 μm depth and then slowly decays, the peak pressure increases with the increase of the laser intensity, and the optimum value of the momentum coupling coefficient (Cm) for the aluminum debris of size range (1-10 cm) is 6.5 dyn.s/j.

Aerodynamical behavior of spherical debris in the supersonic and rarefied wind tunnel MARHy

The atmospheric re-entry of space debris poses a significant risk to humans in the event of a ground impact. Predicting the trajectory of space debris is still a very complex task. The debris passes through different flow regimes and this makes it difficult to correctly estimate its aerodynamic behavior. This work responds to the need of setting up experimental databases in the transition and the slip flow regimes that will enable to validate the numerical codes. This paper presents the experimental results based on the study of the influence of rarefied effects on the shock shapes around the spheres. The experiments were conducted in the MARHy super-hypersonic rarefied wind tunnel, with flows at Mach 4 and Knudsen numbers ranging from 3×10−3 to 6×10−2. The shape of the shock waves and the standoff were determined by CMOS camera visualization. The total pressure flow field around the spheres was measured by a Pitot tube. Numerical modelling for a test case was performed using the Monte Carlo code DS2V, and validated with the experimental measurements.

Can We Estimate Air Density of the Thermosphere with CubeSats?

The measurement of air density in the Earth’s thermosphere has a wide range of scientific applications from space weather to upper atmosphere dynamics, but also technical applications from satellite control to predictions of atmospheric reentry of space debris. This study models the torques applying on a three-unit CubeSat in low Earth orbit to infer the capability of such platforms to measure the air density along their orbit. Realistic noise levels of available CubeSat components are used, and sensitivity to the various noise sources is presented. The precise knowledge of the spacecraft attitude, angular acceleration, residual magnetic dipole, and center of gravity is critical to allow proper air density retrieval. Winds in the thermosphere also have a significant impact on the thermosphere density retrieval, suggesting that this parameter can also be constrained. Attitude control is not necessary if the attitude itself is properly known. The application to the EntrySat CubeSat predicts that such retrieval is possible at altitudes lower than 200 km with errors lower than 30%. The air density retrieval from CubeSat platforms will open new capabilities to infer upper atmosphere dynamics.

Laser impulse coupling measurements at 400 fs and 80 ps using the LULI facility at 1057 nm wavelength

At the École Polytechnique « LULI » facility, we have measured the impulse coupling coefficient Cm (target momentum per joule of incident laser light) with several target materials in vacuum, at 1057 nm and 400 fs and 80 ps pulse duration. A total of 64 laser shots were completed in a two-week experimental campaign, divided between the two pulse durations and among the materials. Our main purpose was to resolve wide discrepancies among reported values for Cm in the 100 ps region, where many applications exist. A secondary purpose was to compare Cm at 400 fs and 80 ps pulse duration. The 80 ps pulse was obtained by partial compression. Materials were Al, Ta, W, Au, and POM (polyoxymethylene, trade name Delrin). One application of these results is to pulsed laser ablation propulsion in space, including space debris re-entry, where narrow ranges in Cm and specific impulse Isp spell the difference between dramatic and uneconomical performance. We had difficulty measuring mass loss from single shots. Imparted momentum in single laser shots was determined using pendulum deflection and photonic Doppler velocimetry. Cm was smaller at the 400 fs pulse duration than at 80 ps. To our surprise, Cm for Al at 80 ps was at most 30 N/MW with 30 kJ/m2 incident fluence. On the other extreme, polyoxymethylene (POM, trade name Delrin) demonstrated 770 N/MW under these conditions. Together, these results offer the possibility of designing a Cm value suited to an application, by mixing the materials appropriately.

Impulse calculation and characteristic analysis of space debris by pulsed laser ablation

Ablation by high-energy pulsed laser provides recoil impulse that results in the de-orbiting and atmospheric re-entry of space debris, which may be the best method of clearing space debris in the size range of 1–10cm. Both the magnitude and direction of the recoil impulse depend on the shape and orientation of the target and serve as the foundation for studying orbital evolution and evaluating removal effects. However, how to calculate the recoil impulse and analyze the features of recoil impulse have not received sufficient attention in the literature. Based on certain assumed conditions, a general numerical method is proposed to calculate the recoil impulse of free motion debris under a set of laser pulses. Selecting cylindrical debris as the research target, we derive an analytical method to calculate the ablation-driven impulse. Moreover, the characteristics of single impulses changing over time and the total impulse are examined using analytical expressions. Finally, simulation experiments are conducted to validate both the numerical and analytical methods.

Space Debris Reentry Analysis Methods and Tools

The reentry of uncontrolled spacecraft may be broken into many pieces of debris at an altitude in the range of 75-85 km. The surviving fragments could pose great hazard and risk to ground and people. In recent years, methods and tools for predicting and analyzing debris reentry and ground risk assessment have been studied and developed in National Aeronautics and Space Administration (NASA), European Space Agency (ESA) and other organizations, including the group of the present authors. This paper reviews the current progress on this topic of debris reentry briefly. We outline the Monte Carlo method for uncertainty analysis, breakup prediction, and parameters affecting survivability of debris. The existing analysis tools can be classified into two categories, i.e. the object-oriented and the spacecraft-oriented methods, the latter being more accurate than the first one. The past object-oriented tools include objects of only simple shapes. For more realistic simulation, here we present an object-oriented tool debris reentry and ablation prediction system (DRAPS) developed by the present authors, which introduces new object shapes to 15 types, as well as 51 predefined motions and relevant aerodynamic and aerothermal models. The aerodynamic and aerothermal models in DRAPS are validated using direct simulation Monte Carlo (DSMC) method.

Review: Laser-Ablation Propulsion

LASER ablation propulsion (LAP) is a major new electric propulsion concept with a 35-year history. In LAP, an intense laser beam [pulsed or continuous wave (CW)] strikes a condensedmatter surface (solid or liquid) and produces a jet of vapor or plasma. Just as in a chemical rocket, thrust is produced by the resulting reaction force on the surface. Spacecraft and other objects can be propelled in this way. In some circumstances, there are advantages for this technique compared with other chemical and electric propulsion schemes. It is difficult to make a performance metric for LAP, because only a few of its applications are beyond the research phase and because it can be applied in widely different circumstances that would require entirely different metrics. These applications range from milliwatt-average-power satellite attitude-correction thrusters through kilowatt-average-power systems for reentering near-Earth space debris and megawatt-to-gigawatt systems for direct launch to lowEarth orbit (LEO). We assume an electric laser rather than a gas-dynamic or chemical laser driving the ablation, to emphasize the performance as an electric thruster. How is it possible for moderate laser electrical efficiency to givevery high electrical efficiency? Because laser energy can be used to drive an exothermic reaction in the target material controlled by the laser input, and electrical efficiency only measures the ratio of exhaust power to electrical power. This distinction may seem artificial, but electrical efficiency is a key parameter for space applications, in which electrical power is at a premium. The laser system involved in LAP may be remote from the propelled object (on another spacecraft or planet-based), for example, in laser-induced space-debris reentry or payload launch to low planetary orbit. In other applications (e.g., the laser–plasma microthruster that we will describe), a lightweight laser is part of the propulsion engine onboard the spacecraft.