Space debris effect on solar radiation propagation

The growing amount of space debris (SD) in near-Earth space already poses a threat to space activities, interferes with astronomical observations, and may lead to negative environmental consequences on Earth in the future. This paper estimates the current attenuation of solar radiation in the wavelength range from vacuum ultraviolet to infrared. We determine the rate of exponential increase in SD mass. Estimates of the future SD mass are also obtained at which the logarithm of solar radiation attenuation will increase to 10⁻⁶–10⁻³. We find the time required for the logarithm of solar radiation attenuation to increase to 10⁻⁶.

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.

Space debris removal – Review of technologies and techniques. Rigid coupling between space debris and service spacecraft

In the light of the intensive activities of various countries, international and commercial organizations in near-Earth outer space (NOS), there is a continuous increase in the number of space objects (SO), the main part of which is "space debris" – these are elements of launching rocket and space technology, spent artificial Earth satellites (ISS), as well as fragments of their destruction, remaining on near-Earth or-bits. A significant part of such objects are located in the low-orbit area of the NOS, creating prerequisites for collisions in space that can cause damage to the target orbital space assets. In these circumstances, conducting effective monitoring of space objects in order to prevent disasters is a key task of the Automated Warning System for Dangerous Situations in Near-Earth Space (ASPOS NOS) of the state Corporation Ros–Kosmos. Improving the quality and reducing time in the field of determining the type of SO, assessing its purpose and condition, as well as the alleged threat to the nearest satellite based on information obtained using radar facilities that provide the highest throughput and continuity of monitoring of the NOS, in the current situation is impossible without the use of effective tools that allow classifying the type of SO in automatic mode realization of reflected radar signals from objects that are complex in design and change their position. Goal – to form a mathematical model of the process of determining the type of SO based on radar non-coordinate information (NCI) based on the application of a neural network model in an appropriate information processing technique The external and internal factors of the process of determining the type of SO by radar equipment, which affect its functioning, are considered, and a mathematical model of this process is proposed based on the analysis of radar measurements obtained by means of ASPOS NOS. The presented mathematical model will make it possible to form a neural network model according to the type of radar signature classifier and implement on its basis a methodology for determining the type of SO by radar NKI, which will greatly assist specialists in information processing and disaster prevention in the NOS.

The importance of the space debris problem in the today’s world is generally recognized. The number of space debris objects in near-Earth space is rapidly growing. The goal of this paper is to overview existing methods, systems, and means for space debris removal from low-Earth orbits with the aim to contribute to the solution of a topical problem of outer space utilization: the problem of space debris in near-Earth space. Space debris removal systems are under active development in the leading space countries. The overview showed that in scientific publications a great attention is paid to passive and active methods and means for space debris removal from near-Earth space. Relatively recently, a start was made on studying the feasibility of space debris removal systems using a combined method, which simultaneously uses means developed on the basis of passive and active methods. This paper considers a combined contactless space debris removal system with a service spacecraft equipped with electrojet engines and an aerodynamic compensator in the form of two plates. The combined system implements a directional deorbit of space debris objects by acting thereon with an ion beam. The proposed combined space system may be used to remove space debris from low-Earth orbits to the dense atmosphere followed by its burn-up. The combined line in the development of space debris removal systems is yet to be studied; however, its implementation would offer some advantages over active and passive methods used alone. Because of this, the development of the proposed combined space system with an aerodynamic compensator for contactless space debris removal is a promising line, which poses problems for further studie.

The ever-increasing clogging of near-Earth space by space debris objects of various sizes significantly limits the possibilities of space activities and poses a great danger to the Earth’s objects. This is especially true for low orbits with altitudes up to 2,000 km. The risk of collision of operating spacecraft with space debris threatens their functioning in near-Earth space. To control space debris, use is made of active and passive methods of space debris removal from operational orbits. At present, promising means of space debris removal are a space debris transfer to low-Earth orbits with a lifetime of less than twenty-five years, a transfer to a junk obit, and in-orbit utilization. According to the latest recommendations, space debris objects moved to low-Earth orbits should have a lifetime of less than twenty-five years. In the dense atmosphere, small space debris objects usually burn up completely, while large ones burn up only partially and may reach the Earth. Since space debris motion in the atmosphere can only be predicted with large errors, a timely and accurate prediction of the place and time of fall of large space debris objects onto the Earth is impossible. Space debris objects can remain in junk orbits for hundreds of years without interfering with space projects. This method of space debris removal reduces the risk of collision with space debris objects in the initial orbit, but increases it in the junk one. According to the concept of in-orbit utilization, space debris is considered a resource for the in-orbit industry. An active space debris removal involves high energy expenditures of service spacecraft. In this regard, the task of their estimation becomes important. The goal of this paper is a comparative assessment of the energy expenditures for moving space debris objects into utilization orbits using service spacecraft with electrojet propulsion systems. The problem is solved using methods of flight dynamics, averaging, and mathematical simulation. The novelty of the obtained results lies in the development of a ballistic scheme and a fast procedure to calculate energy expenditures for moving space debris objects to a disposal orbit using service spacecraft with constant low-thrust electrojet propulsion system. The procedure may be used in substantiating and planning space debris transfer from low-eccentricity low-Earth orbits to utilization orbits.

The small orbital debris population and its impact on space activities and ecological safety

The increasing launch rate of spacecraft, particularly due to the deployment of large constellations and miniaturized satellites in Low Earth Orbit (LEO), has led to a significant rise in space traffic and debris. This paper examines emerging technologies and strategies for future Space Traffic Management (STM) to ensure sustainable operations in space. Key focus areas include the use of artificial intelligence (AI) for enhanced Collision Avoidance (CA) systems, the development of advanced Space Surveillance and Tracking (SST) capabilities, and Active Debris Removal (ADR) techniques to mitigate the growing risks associated with space debris. Additionally, the paper explores the potential of in-orbit servicing, re-entry services, and the exploitation of Very Low Earth Orbits (VLEO) and cislunar space. The integration of these technologies and practices is essential to manage the anticipated growth in space activities while minimizing collision risks and ensuring the long-term sustainability of the space environment.

A large amount of space debris has already accumulated in near-Earth space at an alarming rate. If scientists and engineers still cannot figure out a way to clean up the accumulating junk in space, some of this debris will likely fall into the Earth's atmosphere. This article discusses an option for cleaning up this space debris based on minimum uncertainty optical states. In this concept, these states are formed routinely as specific spatial and temporal distribution of light generated by optically adjusted lasers from the International Space Station (ISS), and is transmitted to a microsatellite as a minimum uncertainty spatial mode. The transmitted power is then converted to a train of minimum uncertainty space-time pulses at nearby microsatellite and is used to push space debris away from the ISS. However, the suggested experiment requires the installation of a state-of-the-art laser on the Kibo facility, which is now found on the ISS. This laser facility can provide adequate power and cooling capabilities, as well as a location for the laser, the optics, and the pointing and tracking required in performing the experiment. Though potential problems are expected to arise in implementing this experiment, the possibility of mitigating this orbital debris to keep the Earth's path into space open is still good news. It will be up to engineers and scientists to use these tools wisely and in a timely manner.

Promising method for improving the accuracy of estimates in space debris tasks - Optimal filtering of measurements

Besides the standard application of ion thrusters for the Near-Earth space exploration and cruise missions, there is a problem of removing man-made space debris objects from the Near-Earth space by a weakly diverging ion beam, i.e. by a contactless impact. However, for stable operation of the ion-extraction system of both the ion thruster and the ion source, it is necessary to predict and take into account the thermal deformations of electrodes of the ion-extraction system. The increase in the number of man-made space debris objects in the Near-Earth space hinders the long-term sustainable development of space activities. Many different methods have been proposed for removing large objects into disposal orbits or into low orbits for their further destruction in the dense layers of the Earth's atmosphere. To remove space debris, a service spacecraft can be used, which could approach the space debris to be removed and tow it to the disposal region by a contactless impact. A radio-frequency ion source forming a weakly diverging ion beam, under the influence of which the space debris objects would move in the direction of the disposal orbit, can be used as an onboard device designed for this purpose. Such radio-frequency ion source is in fact a radio-frequency ion thruster. The development of thermal and thermomechanical models of ion thruster and ion source taking into account the requirements for the reliable operation and integration of ion source with service spacecraft systems to provide contactless space debris transportation in space and integrations of ion thruster with onboard systems to provide attitude control or ensure cruise missions is one of the problematic scientific and technical issues. In terms of design, the ion-extraction system of ion thruster and ion source is the most complex unit. When developing the ion-extraction system design, it is necessary to take into account the peculiarities of electrode operation.

The ratio of hazardous meteoroids to orbital debris in near-Earth space

The history of space debris research problem development is presented. The analysis of current state of space debris in near-Earth space is carried out, prerequisites for further growth space debris in near-Earth space are shown. Concrete examples of solving problems of space debris mitigation and protecting spacecraft are demonstrated. For one of the most clogged areas of geostationary orbit, in which there are no natural factors of objects leaving, formed scientific and technical groundwork for implementation of space debris active removal of objects project with using a service spacecraft with an ion beam injection system is considered. The role and contribution of development participants in creation of scientific and technical groundwork are indicated. The advantages of proposed method of remote impact on space objects and technical aspects of the project implementation are shown. It is proposed to use organizational form of promising projects to reduce anthropogenic impact on near-Earth space in the form of a Consortium consisting of scientific, educational and industrial partners. Within framework of this form of interaction, solution of a set of tasks is provided both for creation of new promising rocket and space technology and for the education of personnel for rocket and space industry.

Space debris—man-made non-functional objects of all sizes in near-Earth space—has been recognized as an increasing threat for current and future space operations. The debris population in near-Earth space has therefore been extensively studied during the last decade. Information on objects at altitudes higher than about 2,000 km is, however, still comparatively sparse. Debris in this region is best detected by surveys utilizing optical telescopes. Moreover, the instruments and the applied observation techniques, as well as the processing methods, have many similarities with those used in optical surveys for ‘astronomical’ objects like near-Earth objects (NEOs). The present article gives a general introduction to the problem of space debris, presents the used observation and processing techniques emphasizing the similarities and differences compared to optical surveys for NEOs, and reviews the results from optical surveys for space debris in high-altitude Earth orbits. Predictions on the influence of space debris on the future of space research and space astronomy in particular are reported as well.

ABSTRACTSolar radiation is the main source of energy for the survival of life and its associated activities. It is important to know accurate solar radiation value in areas such as agricultural activities, solar energy systems, heating, and meteorology. In this study, we present a model for the estimation of solar radiation value with other meteorological parameters in cases where solar radiation cannot be measured or not available. This model is based on the relationship between solar radiation and measured air temperature and visibility extremes. As is known, the incident global solar radiation is attenuated by clouds, aerosols, ozone layer, water vapor, etc.. In the model, the attenuation of the solar radiation is expressed by dew point temperature, visibility, and the maximum and minimum air temperatures. Dew-point temperature refers to the effect of water vapor on solar radiation, air temperature extremes are used to signify cloudiness. Visibility also gives the effect on the attenuation of solar radiation by air pollutants and aerosols in the model. The model was applied to the data taken from meteorological stations in Turkey. Error analysis was performed and compared with the models in the literature and satisfactory results were obtained.Abbreviations H: Daily total global solar radiation, units of MJ • m−2 • day−1; H0: Extraterrestrial solar radiation, units of MJ • m−2 • day−1; Hm: Measured daily total global solar radiation, units of MJ • m−2 • day−1; Hc: Calculated daily total global solar radiation, units of MJ • m−2 • day−1; Tmin: Daily minimum temperature, units of °C; Tmax: Daily maximum temperature, units of °C; RH: Tdew: Relative humidity, units of %rh; Dew-point temperature, units of °C