Large satellite constellations are one of the main reasons for an increasing amount of mass being brought into low Earth orbit in recent years. After end of life, the satellites, as well as rocket stages, reenter Earth's atmosphere. This space waste burns up in the atmosphere and thus injects a substantial amount of its matter into the mesosphere and lower thermosphere. A first comprehensive analysis of the anthropogenic injection and a comparison to the natural injection by meteoroids was presented by Schulz and Glassmeier (2021, Advances in Space Research, 67 (3), 1002-1025). They found significant and even the dominant injection of several metal elements regularly used in spacecraft compared to the natural injection. The first observations of space waste remnants in stratospheric aerosol particles (Murphy et al., 2023, PNAS, Vol. 120, No. 43, e2313374120) confirmed several of these estimates, but also revealed differences and new insights: in particular, a much more extensive range of elements. These inventories and observations raise questions of possible environmental effects, especially on the stratospheric ozone layer (Mitchell et al., 2024, Understanding the Atmospheric Effects from Spacecraft Re-entry, ESA, Whitepaper). The current study presents an update to the space waste injection estimates of Schulz and Glassmeier (2021), assessing the years from 2015 to 2025 using available reentry databases but also considering future mass influx scenarios. Combining mass influx data with detailed estimates of average satellite and rocket stage composition as well as ablation factors allows the estimation of the mass injection of 43 elements and thus a much more detailed comparison to the meteoric injection. Comparison of estimated elemental fluxes to stratospheric aerosol data shows excellent agreement. In general, from 2020 onward, a strong rise in space waste mass influx to the atmosphere can be seen, which has led to more than double the atmospheric injected mass in 2024 compared to levels from 2015 to 2020. Future scenarios discussed by Schulz and Glassmeier (2021) may already be reached by the end of 2025. In 2024, 24 elements were dominating the meteoric injection compared to 18 in 2015, this might increase to 30 in the future. Several of them are transition metals, which are known for their catalytic activity. This indicates a substantial risk of long-term adverse effects on the atmosphere such as ozone depletion, radiative effects and changes in cloud formation, if no action is taken. Research is urgently needed into the atmospheric accumulation, chemistry, and general atmospheric effects of specific elements. (c) 2026 The Author(s). Published by Elsevier B.V. on behalf of COSPAR. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Abstract. Before reaching the Jovian system in 2031, the ESA Jupiter Icy Moons Explorer (Juice) spacecraft will perform three Earth flybys. As well as providing gravitational assistance, these flybys are prime opportunities to assess performance and undertake in-flight calibration of the science payload in a well-understood environment. The first such interval occurred in August 2024, dubbed the Lunar-Earth gravity assist (LEGA) as it included a pass by the Moon in advance of the approach to Earth. The unique spacecraft trajectory allowed for sampling of various regions of the magnetosphere before exiting into the solar wind. In this paper, we report on the performance of the Juice magnetometer instrument (J-MAG) during the LEGA. J-MAG comprises three sensors—two fluxgate vector sensors and one Coupled Dark State Magnetometer (CDSM) scalar sensor—all of which were operational during the LEGA period. This represents the first time in the mission that the scalar sensor has operated in its nominal state. Here, we analyse J-MAG observations during key periods of the flyby. As well as inter-sensor comparison, we assess J-MAG data against geomagnetic field models during the approach to Earth, and compare with measurements from other spacecraft at the Moon and in the solar wind, which allow us to make suggestions for future calibration activities. Overall, the three sensors showed excellent performance at this early stage in the mission and confirmed that the scalar sensor meets the requirements for in-flight calibration of the fluxgate sensors at Ganymede. The LEGA also demonstrates the potential value of using cruise phase measurements for scientific exploration and solar wind monitoring.

Satellite mega-constellations are one of the main reasons for the current exponential growth of space flight. The increasingly large number of objects in orbit has already raised much concern about space debris and requires mitigation strategies. The common strategy for low Earth orbit (LEO) objects is to ensure their re-entry into Earth’s atmosphere, where they ablate and burn up, injecting material into the mesosphere and lower thermosphere. We discuss the significance of this anthropogenic injection compared to the natural one originating from meteoric sources, which provide a constant flow of cosmic dust and larger meteoroids into Earth’s atmosphere. Our comparison indicates that already in 2019 the anthropogenic mass injection has been significant (2.8%) compared to the natural injection. This number will rise in the future due to the ongoing implementation of satellite mega-constellations. More than 5,000 constellation satellites are in orbit right now with more than 100,000 proposed. Considering a worst-case scenario, the injection of metals could increase up to 90% and the aerosol injection up to 94% compared to the natural injection. As the material is mainly injected into mesosphere heights, possible influences on mesospheric and even stratospheric chemistry, with effects on the ozone layer, cloud formation or the climate are thinkable. Recent, first observations already confirmed the existence of spacecraft ablation remnants in stratospheric aerosol particles. This emphasizes our theoretically conjectured significance of anthropogenic dust injection . However, further studies, including observations and modeling, are urgently required to further elucidate any atmospheric effects. Precautions need to be discussed now in order to protect our atmosphere from yet another human-made influence, that is space waste.

Induced magnetospheres form around planetary bodies with atmospheres through the interaction of the solar wind with their ionosphere. Induced magnetospheres are highly dependent on the solar wind conditions and have only been studied with single spacecraft missions in the past. Without simultaneous measurements of solar wind variations and phenomena in the magnetosphere, establishing a link between both can only be done indirectly, using statistics over a large set of measurements. This gap in knowledge could be addressed by a multi -spacecraft plasma mission, optimized for studying global spatial and temporal variations in the magnetospheric system around Venus, which hosts the most prominent example of an induced magnetosphere in our solar system. The MVSE mission comprises four satellites, of which three are identical scientific spacecraft, carrying the same suite of instruments probing different regions of the induced magnetosphere and the solar wind simultaneously. The fourth spacecraft is the transfer vehicle which acts as a relay satellite for communications at Venus. In this way, changes in the solar wind conditions and extreme solar events can be observed, and their effects can be quantified as they propagate through the Venusian induced magnetosphere. Additionally, energy transfer in the Venusian induced magnetosphere can be investigated. The scientific payload includes instrumentation to measure the magnetic field, electric field, and ion-electron velocity distributions. This study presents the scientific motivation for the mission as well as requirements and the resulting mission design. Concretely, a mission timeline along with a complete spacecraft design, including mass, power, communication, propulsion and thermal budgets are given. This mission was initially conceived at the Alpbach Summer School 2022 and refined during a week-long study at ESA's Concurrent Design Facility in Redu, Belgium.

The wave telescope technique is used to reconstruct spatial power distributions of space plasmas from multipoint spacecraft missions. This study aims to quantify the impact of uncalibrated uncertainties in the time synchronization and the spatial position on the accuracy of the wave telescope method for observatories with more than four spacecraft, for example, HelioSwarm a nine-spacecraft NASA observatory currently in Phase B. We simulate synthetic data with systemic timing and spatial errors modeled using geometries drawn from HelioSwarm's Design Reference Mission, applying the wave telescope technique to estimate wavevectors for two characteristic ion-scale waves. By carefully selecting optimal polyhedral configurations from the overall geometry, and combining signals from multiple polyhedra, the impact of systematic uncertainties and spatial aliasing can be significantly reduced, leading to more accurate wavevector identification for future multipoint missions.

The wave telescope is a multi-spacecraft method that uses multi-point magnetic field data to estimate a spectrum in k-space, allowing for the detection of waves as well as turbulence. So far, the wave telescope has been applied to the Cluster and MMS four-spacecraft missions around Earth. In the future, it can be used for multi-scale plasma missions incorporating larger numbers of spacecraft. Such are the accepted Helioswarm mission as well as the proposed Plasma Observatory. Due to the more complicated nature of the wave telescope analysis of multi-scale spacecraft configurations, there is a need to study such systems beforehand using as-realistic-as-possible artificial data. Such an artificial 2D or 3D dataset can be provided by Vlasiator, a Hybrid-Vlasov global magnetospheric simulation treating electrons as a fluid and protons being described by distribution functions. We apply the wave telescope to spacecraft configurations both different in number and position and determine the quality of detection of foreshock plasma waves simulated by Vlasiator.

Spacecraft constellations consisting of multiple satellites are becoming more and more interesting not only for commercial use but also for space science missions. The proposed and accepted scientific multi-satellite missions that will operate within Earth's magnetospheric environment, like HelioSwarm, require researchers to extend established methods for the analysis of multi-spacecraft data to more than four spacecraft. The wave telescope is one of those methods. It is used to detect waves and characterize turbulence from multi-point magnetic field data, by providing spectra in reciprocal position space. The wave telescope can be applied to an arbitrary number of spacecraft already. However, the exact limits of the detection for such cases are not known if the spacecraft, acting as sampling points, are irregularly spaced. We extend the wave telescope technique to an arbitrary number of spatial dimensions and show how the characteristic upper detection limit in k space imposed by aliasing, the spatial Nyquist limit, behaves for irregularly spaced sampling points. This is done by analyzing wave telescope k-space spectra obtained from synthetic plane wave data in 1D up to 3D. As known from discrete Fourier transform methods, the spatial Nyquist limit can be expressed as the greatest common divisor in 1D. We extend this to arbitrary numbers of spatial dimensions and spacecraft. We show that the spatial Nyquist limit can be found by determining the shortest possible basis of the spacecraft distance vectors. This may be done using linear combination in position space and transforming the obtained shortest basis to k space. Alternatively, the shortest basis can be determined mathematically by applying the modified Lenstra–Lenstra–Lovász (MLLL) algorithm combined with a lattice enumeration algorithm. Thus, we give a generalized solution to the determination of the spatial Nyquist limit for arbitrary numbers of spacecraft and dimensions without any need of a priori knowledge of the measured data. Additionally, we give first insights into the application to real-world data incorporating spacecraft position errors and minimizing k-space aliasing. As the wave telescope is an estimator for a multi-dimensional power spectrum substituting spatial Fourier transform, the results of this analysis can be applied to power spectral density estimation via Fourier transform or other methods making use of irregular sampling points. Therefore, our findings are also of interest to other fields of signal processing.

Mars, lacking an intrinsic dynamo, is an ideal laboratory to comparatively study induced magnetospheres, which can be found in other terrestrial bodies as well as comets. Additionally, Mars is of particular interest to further exploration due to its loss of habitability by atmospheric escape and possible future human exploration. In this context, we propose the Mars Magnetospheric Multipoint Measurement Mission (M$^5$), a multi-spacecraft mission to study the dynamics and energy transport of the Martian induced magnetosphere comprehensively. Particular focus is dedicated to the largely unexplored magnetotail region, where signatures of magnetic reconnection have been found. Furthermore, a reliable knowledge of the upstream solar wind conditions is needed to study the dynamics of the Martian magnetosphere, especially the different dayside boundary regions but also for energy transport phenomena like the current system and plasma waves. This will aid the study of atmospheric escape processes of planets with induced magnetospheres. In order to resolve the three-dimensional structures varying both in time and space, multi-point measurements are required. Thus, M$^5$ is a five spacecraft mission, with one solar wind monitor orbiting Mars in a circular orbit at 5 Martian radii, and four smaller spacecraft in a tetrahedral configuration orbiting Mars in an elliptical orbit, spanning the far magnetotail up to 6 Mars radii with a periapsis within the Martian magnetosphere of 1.8 Mars radii. We not only present a detailed assessment of the scientific need for such a mission but also show the resulting mission and spacecraft design taking into account all aspects of the mission requirements and constraints such as mass, power, and link budgets. This mission concept was developed during the Alpbach Summer School 2022.

The strong growth of the space sector along with the use of smaller satellites, for example Cubesats, has fueled the rising implementation of satellite constellations. Not only in commercial spaceflight small satellite constellations are used frequently - there also have been ideas put forward for scientific missions using constellations exceeding the 4 spacecraft constellations previously used for in-situ multi-point measurements in space plasma physics (e.g. CLUSTER or MMS). Thus, there is a need to expand current analysis techniques of those multi-point measurements to more than 4 spacecraft and characterize the benefits of a larger number of satellites. Such an analysis technique is the wave telescope, e.g. introduced in Motschmann et al., 1996. The wave telescope allows to use e.g. magnetic field data from different points in space (the different spacecraft) to estimate a spatial fourier transform and with that is able to detect multiple waves. Thus, using a confined time interval, the frequency and wave vector of several different waves can be detected with high precision. Since its introduction, the wave telescope has been successfully applied for detection of waves in in-situ magnetic field data from Earth's magnetospheric environment. Using artificial data of magnetic plane waves in simulations, we revisit the limitations of the wave telescope for satellite numbers of 4 or less and explore the quality of detection for satellite configurations of 5 and more spacecraft. We present structured analysis of the spatial analysis limit from 1D upwards, named the nyquist wavenumber or wave vector (analogous to the nyquist frequency in the frequency domain). Additionally, we show that the wave telescope suffers from so called spatial blindness when the chosen satellite configuration is not moving and non-random phase plane waves at the same frequency are present. This blindness reduces the possible number of waves detected to no more than one.

Rocket emissions and debris from spacecraft falling out of orbit are having increasingly detrimental effects on global atmospheric chemistry. Improved monitoring and regulation are urgently needed to create an environmentally sustainable space industry.

Every year, more and more objects are sent to space. The increasing number of countries with space programs, advancing commercialization, and ambitious satellite constellation projects raise concerns about space debris and the increase of mass flux into the atmosphere due to deorbiting of satellites and rocket bodies. A comparison of this anthropogenic influx to the natural influx due to meteoroids is presented giving detailed information about the mass, composition and ablation of the entering matter. Currently, anthropogenic material does make up about 2.8% compared to the annual injected mass of natural origin. For two different future scenarios considering planned and already partially installed large satellite constellations this fraction increases to nearly 13%, respectively 40%. For these cases, the anthropogenic injection of several metals prevails the injection by natural sources by far. Considering different ablation products, we find that the anthropogenic injection of aerosols into the atmosphere increases disproportionately. Today, they make up about 1% compared to the injected aerosol mass of natural origin, increasing to 30% and 94% for the two future scenarios, respectively. Considering the injection of atoms, the natural injection is dominant by far. For the two future scenarios, the anthropogenic injection is only at 5%, respectively 15% compared to the annual natural atom injection. The predicted strong increase in anthropogenic injection will make it significant in comparison to the natural injection which can have yet unknown effects on Earth's atmosphere and the terrestrial habitat. (C) 2020 COSPAR. Published by Elsevier Ltd. All rights reserved.

The increasing activities in space due to more and more countries with space programs, advancing commercialization, and large satellite constellation projects lead to a rising number of human-made objects in space. While many of those stay in orbit at high altitudes, objects in low Earth orbit reenter the atmosphere mostly disintegrating and injecting material into the atmosphere. The growing concern about space debris has led to policies encouraging deorbiting of satellites at the end of their lifetime. All that will increase the annual mass influx into the atmosphere by human-made (anthropogenic) objects in the future. We compare the influx of those objects to the natural mass influx of entering meteoroids of asteroidal, cometary, and planetary origin into Earth's atmosphere. We look at the mass and the elemental composition of the entering bodies also incorporating different ablation of those objects. This way, a quantitative assessment of the annual injection of aerosols and atomic remnants into the atmosphere is possible. Today, anthropogenic material makes up way less than 1 % of the overall injected mass. However, future large spacecraft constellations could increase the anthropogenic influx significantly, then contributing 4 % or more of the whole injection. As spacecraft have a high abundance of metal elements, the metal mass portion of the injection can reach up to 15 %. For some elements, the anthropogenic injection may even prevail the natural injection. This implies for future large satellite constellations that the anthropogenic injection can become significant with unknown effects on the upper atmosphere and the terrestrial habitat.

Measurement data of several digital AMR-magnetometers taken in 'Magnetsrode' Magnetic Laboratory (Braunschweig, Germany) in form of .txt files. MATLAB Code for analysis of that Data. Measurement Log for additional measurement information. Empty folders should remain as they are for MATLAB folder structure when using the provided code.

Magnetometers based on the anisotropic magnetoresistive effect are used in many applications for orientation determination, by measuring the magnetic field of the Earth. As sensors of this type are commercial, off-the-shelf components, manufacturers provide limited information on their measurement performance. Therefore, we present a (to date) unprecedented comprehensive calibration study on three state-of-the-art digital anisotropic magnetoresistance magnetometers, to precisely determine various performance parameters and stability across different sensors of the same model. With the evaluation of sensitivity, noise, offset, and orientation determination, as well as considering dependencies on temperature and frequency, the performance of each sensor can be improved significantly, enabling their implementation in demanding fields of application (such as in satellites). Different measurement and calibration techniques, specifically aimed at the characteristics of the examined magnetometers, were utilized, using a sophisticated magnetic laboratory that has served as a calibration facility for several interplanetary space missions. Our study allows operators to decide whether to consider anisotropic magnetoresitance magnetometers for their application and, more importantly, to be able to (at least partially) skip a time-intensive and complicated calibration by using the sensor parameters given in this paper. To that end, the most promising sensor is recommended. The sensor examination suggests a good comparability of different sensors of the same model, and shows the importance of noise regarding the sensor performance with a noise floor up to 124 nT/Hz at 1 Hz. Additionally, depending on the sensor model, the sensitivity is 14 nT at best, and the attitude determination error can be reduced to about 0.3° with the given calibration.