Numerical simulation of high-velocity impact effect on spacecraft structure

The problems of assessing a risk of damaging a spacecraft by meteoroids and space debris are fairly important. The probability of not damaging a SC depends on the properties of its structural elements, particle flux density and velocity of hypervelocity meteoroids and/or space debris. This article offers an analytical review of papers (primarily foreign ones) assessing velocity of meteoroids based on the experimental evidence. Stated are general requirements for experimental data acceptable for acquiring reliable meteoroid velocity data. Compared are meteoroid velocity values obtained from different models, including the data presented in the current national domestic standards. Based on the analysis of experimental data accumulated so far, the most probable values of meteoroid and space debris velocities to be used in ballistic limit equations have been proposed. Key words: meteoroid, space debris, spacecraft shielding against meteoroids, meteoroid environment, meteoroid flux density and velocity.

The consequences of large, catalogued “space debris” near Earth are well described in the literature, but the threat of small debris is often overlooked, despite the fact that they pose a serious threat. Achieving a more complete understanding of the latter (their quantity, composition, spatial distribution, dynamics and level of danger) is hampered by at least two factors: a clear underestimation of the danger of small debris and a lack of appropriate measurements, a direct consequence of the lack of equipment and resources capable of observing them. The report assesses the quantity, mass and dynamics of the population of small space debris in low Earth orbit, as well as the consequences (in terms of the progressive increase in the number of space debris) of the implementation of plans for the deployment of multifunctional communication space systems there. The latter aspect makes research in this area particularly relevant. It examines various aspects of the consequences of artificial debris in near-Earth space, as well as the specific hazards that small space debris pose to space activities and the ecology of the Earth and near-Earth space, compared to the hazard posed by large debris. A significant lack of complete and reliable data on small space debris is identified due to the lack of observational tools.

We are today facing a huge issue on the concentration of space debris in near-Earth space. More than 15,000 debris have been recorded, and this represents a danger for current and future missions to space. A solution to this issue is to remove these spacecrafts from orbit. One of the ways to do it is to use inflatable device. These braking device can be installed on the landing vehicles on Earth, before their launch, or after they have been labelled as space debris. Studies have already been conducted about inflatable device. The results of these studies show that using an inflatable device on an orbital spacecraft significantly reduces its lifetime (it then does not exceed 25 years in most cases). Using inflatable device instead of rigid device has advantages, such as a small mass and a great compacity, which is convenient to respect the required launching volume.

Space debris has reached alarming proportions and is growing at a frightening pace, because of the expanding number of satellites circulating in Low Earth Orbit (LEO), designed to increase global Internet coverage and provide earth observation data. LEO satellites are now being launched in mega-constellations, including by Elon Musk's company SpaceX. It is time to completely overhaul the 1967 Outer Space Treaty, which was not designed to deal with current problems. The COP forum should therefore include the near-earth environment within its concept of the earth's climate, enabling the UN to acknowledge, as a collective, the growing menace of human-made debris in near-earth space, and, in partnership with the UN-Outer Space Affairs Office (UN-OOSA), call for a new declaration on LEO.

This paper describes the numerical models designed by the authors to investigate the formation, orbital evolution, and spatial distribution of fragments of space debris emerging in orbits as a result of space-craft fragmentation. It cites the results of the testing of the models and the data of their use.

Micrometeoroid/Orbital Debris (MMOD) Impact Detection and Location Using Fiber Optic Bragg Grating Sensing Technology

The international legal aspects of operations for active removal of space debris (SD) from near-Earth space (NS) are considered. An analysis is made of the factors determining the responsibility of launching states for damage caused by their space means to other participants in space activities (SA). Attention is focused on the need to develop the legal framework for the implementation of commercial projects in outer space.The international legal aspects of operations for active removal of space debris (SD) from near-Earth space (NS) are considered. An analysis is made of the factors determining the responsibility of launching states for damage caused by their space means to other participants in space activities (SA). Attention is focused on the need to develop the legal framework for the implementation of commercial projects in outer space.

At present in near-Earth space, there are more than two thousand operating spacecraft and more than five thousand non-functioning satellites, which have failed or run out of fuel. The last ones are not only satellites that do not carry out their functions but are also space debris. And launching new satellites to replace the failed ones is an expensive process. Therefore, the concept of a serviced space and the development of service satellites to extend the life of existing spacecraft are becoming expedient. On-orbit satellite servicing tasks can include inspection of the target satellite, replacement of failed units and repair work, correction of the satellite orbit, or putting into a disposal orbit, refueling satellites. The work reviewed service satellites and the space experiments carried out, presented the main service stages, analyzed the operations conducted during the experiments, and identified the key critical service technologies.

Introduction Ballistic limit equations (BLEs) are used to predict the performance of a spacecraft shield or component when impacted by a space debris particle. Together with impact flux estimates, BLEs are inputs to mission risk assessments which estimate the probability of mission failure arising from operating spacecraft in a congested debris environment. For such risk assessments a BLE must be assigned to every external structure and critical component onboard a spacecraft, including dedicated shielding, thermal blankets, batteries, propellent tanks, cable harnesses, etc. NASA’s handbook on micrometeoroid and orbital debris (MMOD) protection [1] provided an overview of many BLEs, together with an accompanying software package [2] and user manual that includes validation information for many of the equations [3]. However, the software package in [2] had limited distribution, was closed-source, and was never updated. Although most BLEs are straight-forward to implement in risk assessment software packages, some include recursive constants that require optimization during the calculation, e.g., the Reimerdes-modified Whipple shield BLE [4], etc. In addition, several original BLE publications include typos and mistakes, e.g., [3][4], complicating their replication, see e.g., [5].

Orbital debris and meteoroids: Results from retrieved spacecraft surfaces

The processes of space debris formation are described; the urgency of the problem of its removal from near-Earth space is noted. A method to prevent the clogging of space by equipping a spacecraft to be launched into orbit with additional devices, simple in design and mode of operation, is presented. The results of the estimation of aerothermodynamics, bulk–mass characteristics and trajectories of low-orbit spacecraft equipped with a space debris disposal system are presented.

One of the urgent nowadays problem is to determine the characteristics of space debris (SD) in near-Earth space. Non-functioning space vehicles and their remains, collectively referred to as SD, are located both at low altitudes of up to 2000 km, orbits, and in orbits between 19,000 and 22,000 km, and in the geostationary ring above 32,000 km. Most of these objects are in high-inclination orbits, the planes of which intersect, so the average relative speed of their mutual flight is about 10 km/s. Due to the huge supply of kinetic energy, the collision of any of these objects with an operating spacecraft can damage it or even disable it. Small fractions of space debris pose the main threat to the implementation of safe space activities, since the intensity of passage through a unit of surface for small-sized (less than 10 cm) fractions is about an order of magnitude greater than for fractions more than 10 cm. Therefore, effective information support for the safety of space activities is possible only in the organization of continuous operational control of not only large, but small-sized space objects, including small fractions of space debris. In To identify the geometric shape of space debris objects, to clarify their flight orbit, the presence of rotation, an optimal algorithm for the inverse synthetic aperture radar imaging of space debris objects in the multi-position radar system is proposed. In this paper, an analysis of the trajectory signal was carried out, potential resolutions were obtained in terms of range and azimuth, an estimate of the synthesizing time was made.

In low Earth orbit (LEO), the large-scale and long-term orbital spacecraft is likely to be impacted by micrometeoroids and orbital debris (MMOD), which will lead to gas leakage and then seriously threaten the safety of spacecraft and astronauts. However, it is still a challenge task to locate the leakage source, due to the randomness, multiband and dispersion of the leakage signal. Targeting sensing the gas leakage in time and accurate localization of the leakage source, an improved beamforming algorithm is proposed, and used to locate the leakage source of 1 mm, 2 mm and 3 mm diameter holes respectively. The improved algorithm uses a narrowband filter with automatic frequency window to select the best frequency band, as well as to delay overlay different signal speeds with various frequency bands via a dispersion curve. Experimental results show that the improved algorithm can accurately locate the artificial leak sources with different diameters.

Orbital debris, or space junk, is a major environmental externality that poses serious risks to human activity in outer space. The rapid increase in satellites and spacecraft from commercial, military, and scientific missions has intensified space pollution, leaving millions of debris fragments orbiting Earth at high velocities. This proliferation raises the likelihood of collisions and the destruction of operational spacecraft. This paper examines how spacecraft shielding affects both collision-related damage and debris generation. Shielding lowers the probability of satellite breakup during collisions, helping limit the creation of additional debris. It illustrates how spacefaring firms can mitigate the environmental costs of space activity through individual actions, even within a decentralized, profit-driven framework. Our analysis shows that when satellite operators invest in reducing collision risks and potential destruction, their behavior partially internalizes the externality, improving orbital sustainability. However, the optimal level of shielding in a decentralized economy remains below that achieved under a centralized framework, demonstrating that market mechanisms only partially address the negative externality.

The end-of-life disposal of Galileo satellites is needed to avoid collisions with operational spacecraft and to prevent the generation of space debris. Either disposal in stable graveyard orbits or disposal into the atmosphere exploiting eccentricity growth caused by lunisolar resonances are possible. However, there is a concern about the predictability of MEO orbits because of possible chaotic behaviour caused by the overlap of resonances. In this work, we investigate if Galileo disposal orbits are predictable and if safe disposal is possible under initial uncertainties. For this, we employ finite-time Lyapunov exponents (FTLE) and sensitivity analysis and compare these two methods regarding their practicality for analysing the predictability of disposal orbits. The results show that FTLE are not suitable for determining if an orbit behaves chaotically or not on the time scale of interest. Sensitivity analysis, on the other hand, can be used to quantify the effect of uncertainties on the orbital evolution and to determine if safe disposal is possible. In addition, we show that reliable re-entry disposal is feasible with a limited \Delta V budget. However, safe disposal into a graveyard orbit is not always feasible considering uncertainties in the disposal manoeuvre and dynamical model when the available \Delta V for disposal is low.