Orals: Fri, 8 May, 16:15–18:00 | Room 1.85/86
The space sector has experienced significant growth in recent years, with rocket launch rates increasing from 102 in 2019 to 329 in 2025. Launch and re-entry operations of space transportation systems are the only source of anthropogenic emissions in the upper atmosphere. This increase in space activities is raising concerns about both ozone and climate effects. In recent years, there has been an increasing number of studies assessing the effects of these emissions using global Earth system models. For accurate assessments of the atmospheric effects, emission inventories that take into account the individual characteristics (trajectory, propellant, engine parameters, materials) of launches and re-entries are required.
This study addresses the general problem of how to model launch and re-entry emissions of space transportation systems under contemporary and near-future operational conditions. Here, we present results using the Launch Emissions Assessment Tool (LEAT) and the Re-entry Emissions Assessment Tool (REAT) to model all orbital space transportation missions conducted between 2019 and 2025. We show that the combined LEAT–REAT framework enables modelling of emission composition, trajectories, and altitude-dependent chemical effects of afterburning for multiple propulsion technologies and vehicle configurations. Compared to previous approaches that relied on generic profiles, the new toolset captures individual flight paths, staging and fragmentation events, and vehicle-specific launch and re-entry combustion modelling, pointing out uncertainties compared to previous emission inventories. The results are compared with natural sources such as meteorites and other anthropogenic sources. An assessment of uncertainties via the implementation of a parameter study concludes the presentation.
In a further step, future measures for modelling the reaction pathways in the upper atmosphere are presented.
How to cite: Fischer, J.-S., Neubert, J., Fasoulas, S., Nützel, M., and Schmidt, A.: Development of space transportation launch and re-entry emission inventories for 2019-2025, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4786, https://doi.org/10.5194/egusphere-egu26-4786, 2026.
Space traffic is increasing rapidly, with a threefold increase in launches and a thirtyfold increase in satellites launched between 2000 and 2024 (Taupin et al., 2025). In 2024, we estimate that the ratio between the re-entered dry-mass from anthropogenic space activities (DISCOSWeb, J.McDowell RCAT) and natural input from Earth’s cosmic natural input (Carrillo-Sánchez et al., 2020) is between 20-40%. For aluminum in particular, this ratio was estimated to exceed 100% in 2024 (Ferreira et al., 2025). In addition, the space traffic increase is mainly occurring below 600 km altitude, where satellites naturally decay in less than ~10 years. This mass is ablated in the form of atoms and solid aerosols that accumulate in the stratosphere. They may impact radiative forcing and ozone depletion, and have other unknown effects at local, regional and global scales (Ferreira et al., 2024, Ross et al., 2014). It is therefore important to accurately quantify the past and present levels of these injections in order to model their atmospheric effects.
First, we present a finely tuned classification that helps to assess the potential origin of solid stratospheric aerosols (~1-100 microns diameter) collected in-situ by aircrafts mostly over the United States by NASA's Cosmic Dust program between 1981 and 2020. Here we study the 1981-2010 period comprising more than 4 400 particles. Based on the Energy Dispersive X-ray spectra of these particles and previous work (Lasue et al., 2010), we have developed a semi-automated method that classifies them into compositional clusters. For example, we identified potential artificial contaminants rich in Al, Cd, Cu and Ti that stand out from other clusters. For clarity, the particle compositions are compared to known minerals and pure elements. A visualization of the classification will be presented for each year in which particles were sampled, showing the evolution of the aerosol population composition.
Soon, this work will be supplemented by a new spectral analysis of 46 particles that will serve as a calibration to improve the quantification of the chemical composition of all particles in the catalogues.
Secondly, we will introduce a new method for estimating the re-entered ablated mass from space waste. Existing methods rely on average ablation coefficients (Schulz et al., 2021) or focus on specific chemical species (Ferreira et al., 2025). We use the DEBRISK software (from CNES) to estimate several average ablation profiles for a few simplified models of satellites and rocket upper stages based on their different average cross-sections, masses, and orbital parameters. Then, we use these parameters available in DISCOSweb to derive the total ablated mass of satellites and rocket upper stages in the stratosphere from 1981 to 2010. Finally, we estimate the total mass of black-carbon and alumina injected in the stratosphere during all orbital launch on the same period, using a newly created database on propellant masses cross-referencing information from different sources (DISCOSweb, J.McDowell GCAT, user manuals). These numbers will then be compared to the evolution of the solid aerosol population presented in the first part.
How to cite: Taupin, Q., Lasue, J., Määttänen, A., Zolensky, M., Amgoune, V., Annaloro, J., and Bellucci, A.: Evolution of the population of stratospheric aerosols on the 1981-2010 period: focus on injections related to space activities during launch and re-entry of satellites., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12155, https://doi.org/10.5194/egusphere-egu26-12155, 2026.
The number of launches and objects in space has been growing fast in the last few years, particularly due to the growth of satellite mega-constellations. Defunct satellites and other space junk products collide and create a collisional cascade of smaller space debris. Space debris ablates and burns up in the atmosphere upon re-entry and thereby metals and rare materials are injected, some of which already exceed the natural input of exogenous material today.
Quantifying the influx of these anthropogenic materials into the atmosphere is essential to address the possible environmental consequences, through constraining the physico-chemical atmospheric models. This quantification can be done using catalogs of spacecraft being launched, but not all manufacturers provide these data. Small micro-debris can be used as tracers of their larger counterparts through the collisional cascade, which would complement these existing catalogs, for the inventory of elemental compositions of human-made materials in Low EarthOrbit that will re-enter in the atmosphere.
We propose in situ measurements of sub-micrometer and micrometer sized particles as tracers of the larger space debris, using in situ mass spectrometers with a velocity grid, that were originally designed for cosmic dust measurements.
These instruments can measure the elemental composition (impact-speed dependent), mass distribution, surface charge, impact velocity vector, and time-resolved fluxes of dust and debris particles. Moreover, measuring the natural cosmic dust flux itself is necessary as a benchmark for the debris.
In this talk we introduce in situ cosmic dust measurements in the past, the different measurement methods, and measurements of micrometer-sized space debris so far with “active” (time-resolved) and “passive” (sample return) methods. We elaborate on the particles we can expect to measure in orbit, and the science goals to be achieved through such measurements that are useful for both the assessment of the anthropogenic influx into the atmosphere and for space debris research in Low Earth Orbit.
Elemental composition measurements of these micro-debris particles, combined with orbital velocity and location data, offer a new avenue for quantifying the chemical influx of anthropogenic material into Earth’s atmosphere, and for assessing more thoroughly the broader space debris populations.
How to cite: Sterken, V. and Manelli, M.: Constraining the atmospheric influx of anthropogenic materials using in situ micro-debris composition measurements , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1032, https://doi.org/10.5194/egusphere-egu26-1032, 2026.
Ablation of re-entering satellites and rocket stages is expected to become a significant source of metals in the mesosphere, yet systematic observations remain limited so far. We present our initial Li atom observations between about 80 km and 100 km altitude using our lidar at Kühlungsborn, Germany (54°N, 12°E), covering a period between August 2024 and February 2025. The main source of the Li layer is still thought to be cosmic dust ablation. However, lithium is a crucial species for investigating anthropogenic impacts on the middle atmosphere because of its extensive use in the space industry. Our measurements revealed a column abundance mostly between 1x106 cm-2 and 5x106 cm-2. Initial simulations using the WACCM-Li model are in reasonable agreement with the observations, suggesting natural seasonal variability as the primary driver for the changes in Li abundance. Some of the observations in early 2025 showed, however, an unusually high abundance that cannot yet be explained by natural variation. A notable event occurred on February 19-20, 2025, at 00:21 UTC, with the detection of a Li cloud exhibiting densities ten times higher than typical, reaching up to ~30 atoms/cm³. Back-trajectory analysis with UA-ICON indicated the probed air mass originated from a location west of Ireland, coinciding with the atmospheric re-entry of a Falcon 9 upper stage. Simulations of the re-entry process revealed a beginning metal ablation of this rocket stage already around 100 km altitude due to its shallow entry angle. We will present the details of this case study as well as our observations of the typical Li layer. Furthermore, we will show first results of our new 3-channel multi-species lidar (MSL) that is set up to search for different species expected to be ablated by re-entering space debris, like Cu, Hf, AlO, etc., along observations of Li and (purely natural) Na.
How to cite: Gerding, M., Wing, R., Feng, W., Plane, J., Morfa, Y., Yamazaki, Y., Höffner, J., Froh, J., Baumgarten, G., and Stolle, C.: Lithium Observations in the Mesosphere: Seasonal Variability and the Impact of a Falcon 9 Re-entry, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21595, https://doi.org/10.5194/egusphere-egu26-21595, 2026.
The rapid growth of satellite mega-constellations is expected to substantially increase spacecraft disposal and atmospheric reentry rates in the coming decades. As most spacecraft are composed primarily of aluminum, reentries are anticipated to release aluminum oxide (Al2O3, alumina) particles into the upper atmosphere. Alumina efficiently scatters solar radiation and has therefore also been discussed in potential solar radiation modification (SRM) scenarios. However, the respective climatic impact, and even the sign of the radiative forcing, remain highly uncertain due to limited constraints on particle size distributions and associated microphysical processes. Here, the radiative effects of alumina aerosols are investigated using sensitivity experiments with the radiative transfer model libRadtran, complemented by a simplified global climate model to estimate stratospherically adjusted radiative forcings. The analysis focuses on the influence of aerosol particle size, injection altitude, and background atmospheric conditions on radiative forcing and heating rates. Alumina distributions based on two scenarios from Maloney et al. (2025) are considered as reference cases and form the basis for the sensitivity studies: RS1, representing small particles with effective radii of approximately 10nm, and RS2, representing larger particles around 0.1μm. The results demonstrate a strong dependence of both the magnitude and sign of the radiative forcing on particle size and atmospheric background assumptions, particularly cloud configurations. Although the simulated forcings fall within the uncertainty range of Maloney et al. (2025), the RS1 scenario generally produces a positive radiative forcing, whereas the RS2 scenario leads to a negative forcing under most conditions, resulting in signs opposite to their reported best estimates. Potential reasons for these discrepancies are currently being investigated; however, the results generally emphasize the key role of aerosol microphysics and the large uncertainties in the climatic impact of alumina aerosols.
How to cite: Bernlochner, S., Nützel, M., Mayer, B., Schmidt, A., and Maloney, C.: Sensitivity analysis of radiative effects of alumina particles from spacecraft re-entries, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7078, https://doi.org/10.5194/egusphere-egu26-7078, 2026.
There is a significant lack of knowledge about the impact of the ever-increasing number of satellites in the Low Earth Orbit (LEO) that are supposed to demise during re-entry into the upper atmosphere. Aluminum is injected into the upper atmosphere as a rather new element, because it is a major constituent of satellites, while being only a minor constituent of micrometeorites [1]. The impact of this new trace element on the atmospheric behavior is hardly investigated so far.
Current research assumes the immediate oxidation of molten or evaporated aluminum due to the high abundance of reactive atomic oxygen in the upper atmosphere. The reaction leads to either gaseous aluminum monoxide (AlO), to aluminum hydroxides (Al(OH)x), or solid aluminum oxide (Al2O3) particles are formed. During the re-entry airborne observation campaign of the CYGNUS-OA6 re-entry in 2016, we detected spectral signatures of AlO at an altitude of approximately 70km [2]. The formation of (Al(OH)x) [3], as well as the formation of solid aluminum oxide (Al2O3) particles is discussed in literature [4] [5]. However, few experimental data sets are available of these processes. In our group, we are trying to experimentally evaporate aluminum and detect the paths toward aluminum containing products by suitable diagnostic means.
These experimental simulations are performed in the plasma wind tunnels at the Institute of Space Systems (IRS) at the University of Stuttgart. We observed the evaporation of aluminum in a series of experiments using different experimental setups. The sole injection of solid aluminum only led to larger molten droplets released form the solid. In a second setup, a sample of aluminum powder cured in epoxy resin was placed in the plasma flow. The sample ablated, which lead to the evaporation of aluminum powder. A formation of AlO was observed by acquiring spectral signatures of known AlO bands. In a new approach, aluminum powder was ejected against the plasma flow direction through a water-cooled brass probe. This injection method allows for a higher entrainment time and the evaporation of aluminum. Again, the formation of AlO was observed through spectral signatures.
In this presentation, we will give a detailed insight in the experimental work developing an experimental setup to study the processes after the demise of re-entering satellites. Also, we will provide an outlook in the development of experimental setups for the detection of eventually formed solid particles. These experimental studies are of high interest to gain an understanding of the environmental impact of the rising number of re-entering satellites.
[1] Schulz and Glassmeier, Advances in Space Research, 2021.
[2] S. Loehle et al., Meteoritics and Planetary Science, 2021.
[3] Plane et al., JGR Space Physics, 2021
[4] Maloney et al., JGR Atmospheres, 2025.
[5] Park and Leyland, Acta Astronautica, 2021.
How to cite: Kuenstler, D., Leiser, D., Eberhart, M., Fasoulas, S., and Loehle, S.: Update on an Experimental Approach to Assess Particle Formation from Re-entering Spacecraft, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1943, https://doi.org/10.5194/egusphere-egu26-1943, 2026.
In space sustainability the so-called “design for demise” (D4D) approach is advocated as the most sustainable option for the end-of-life of Low Earth Orbit (LEO) spacecraft, the goal being that a minimal footprint of re-entering debris mass survives to ground. Instead it is considered preferable that a majority of spacecraft mass is vaporised or aerosolised in the upper atmosphere. As such it is vital that the nature of the generation of these upper-atmospheric pollutants by demising debris is well understood. Such research sits at the intersection of aerospace engineering and atmospheric science, this work seeks to explore a vehicle-specific engineering analysis.
Recent work on the open-source TransAtmospherIc FlighT SimulAtioN tool (TITAN) developed at the University of Strathclyde has enabled the use of the software as an uncertainty quantification tool. This functionality is applied here in order to explore how the distribution of upper-atmosphere mass emission during demise of a typical LEO satellite can be characterised.
In this work the re-entry of a representative model of a tumbling Starlink satellite is simulated, accounting for 6 Degree-of-Freedom trajectory dynamics and transatmospheric aerothermodynamical effects. Perturbations in terms of initial spacecraft state and temperature, as well as flight-relevant atmospheric conditions, are applied. Then a Monte Carlo campaign is used to recover distributions of emitted species across altitude. Due to the high similarity of Starlink satellites such an approach can be considered generalisable across the constellation, enabling mass emissions predictions to be extended to a global scale.
This work hopes to provide both a tutorial on how such analyses can be performed as well as giving information from a spacecraft-specific perspective that can be applied in atmospheric modelling approaches and also potentially used to inform future compliance behaviours and life cycle analyses.
How to cite: Williamson, T. and Fossati, M.: Uncertainty Quantification of Pollutant Generation During Uncontrolled Re-entry with an Open Source Re-entry Simulator, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11723, https://doi.org/10.5194/egusphere-egu26-11723, 2026.
Rocket launches emit climate-relevant gases and particles in the atmosphere. Although rocket launches are transient and local emission sources, long lifetimes within the upper atmosphere allow the emitted gases and particles to accumulate. This potentially causes a significant climate impact in the future with an expected increasing frequency of launches, e.g. for installation of mega-constellations. The German Aerospace Center (DLR) has launched the S3D-BETTER project in 2026. One of the aims of the project is to assess the potential atmospheric and climatic effects caused by gases and particles emitted from future rocket launches or created in its aftermath via reaction with ambient gases. An exhaust inventory based on hydrogen-fueled reusable launch vehicles from the European Next Reusable Ariane (ENTRAIN) study is used as a case study. The inventory has been developed by DLR and includes eight exhaust species. The atmospheric and radiative effects are calculated for the ENTRAIN rocket launches by using the European Center HAMburg general circulation model (ECHAM) and Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) model. Our simulations provide initial results on atmospheric effects of those rocket launches, particularly focusing on stratospheric ozone changes, and examine the radiative forcing caused by those rocket launches. Remaining challenges for climate-modelling and for future research is also discussed.
How to cite: Yamashita, H., Nützel, M., Schmidt, A., Herberhold, M., Wilken, J., and Maiwald, V.: Quantifying the atmospheric and climatic effects of reusable, hydrogen-fueled rocket launches, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17205, https://doi.org/10.5194/egusphere-egu26-17205, 2026.
Although stratospheric ozone is showing signs of healing following the implementation of the Montreal Protocol, the impact of the rapidly developing space industry may affect the rate and extent of this recovery. We assess the potential for rocket-emitted chlorine, under different scenarios of launch rates, to offset the decrease in chlorine from controlled long lived Ozone Depleting Substances (ODSs). We use the Whole Atmosphere Community Climate Model Version 6 (WACCM6) nudged to meteorological reanalyses in order to simulate realistic atmospheric conditions and variability. Chlorine emissions from modest (×10) increase in launch rates relative to 2019 causes near-global column ozone depletion of less than 0.1 DU (0.04%), while large (×52) growth causes depletion of 0.59 DU (0.23%). These two scenarios respectively cause local ozone decreases of up to 0.4% and 2% in the upper stratosphere. Lower stratospheric loss and column ozone depletion are largest at high latitudes with a pronounced annual cycle and, in the Arctic, large meteorology-driven variability. The impact on Antarctic ozone peaks in October (additional depletion of 0.5 DU (modest growth) and 3 DU (large growth)), while the impact in the Arctic peaks in April (2 DU for large growth). Although the mean impact in the Arctic is much smaller than for the Antarctic, the ozone loss shows large variability. In very cold years (exemplified by 2010/11 meteorology), the column loss in the Arctic exceeds the Antarctic for all launch scenarios and can exceed 8 DU for large growth. Ozone depletion in both the polar lower stratosphere and upper stratosphere shows a linear dependence on the level of chlorine enhancement. Overall, the estimated impact of rocket-emitted chlorine for reasonable growth scenarios is small but does have the potential to offset some of the gains of the Montreal Protocol. This impact needs to be considered when deciding on propulsion systems for future launches and in projections of ozone layer recovery.
How to cite: Li, Y., Feng, W., Plane, J. M. C., Wang, T., and Chipperfield, M. P.: The Impact of Rocket-Emitted Chlorine on Stratospheric Ozone, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8440, https://doi.org/10.5194/egusphere-egu26-8440, 2026.
With the number of rocket launches increasing almost exponentially in the last years, a trend that will presumably continue, the question of the environmental impact of rocket launches becomes more and more important. However, rocket plume investigations in the past were mostly focused on engine monitoring and not on environmental aspects, so the amount of experimental data related to ozone-destroying radicals, carbon oxides and soot is limited.
As a first step in tackling this problem, spectroscopic measurements of rocket exhaust plumes were taken during ground-based LOX/methane rocket engine tests at the test benches at DLR Lampoldshausen.
Emission spectroscopy in the UV-VIS range enables non-intrusive measuring of light emitted by chemically excited species within the plume as they fall back to their ground states. Each atom or molecule emits light at characteristic wavelengths, so it can be identified and analysed in the measured spectra. The focus was placed on OH* and CH*, well-known intermediate products of methane combustion, as well as C2* which could serve as an indicator for soot formation.
Since the shape of the exhaust plume, i.e. the location of the Mach disk, its diameter or its inner structure, can vary drastically during different operating conditions throughout a test run, time resolved comparison of measurement position and plume structure was made possible with complementary imaging of the plume.
Through careful intensity calibrations, post-processing and geometric analysis, the actual amount of the emitting excited state molecules in the plume can then be calculated from the measured spectra and the results will be presented at the conference. While these excited state species do not immediately provide information about the total species population without further analysis, they nonetheless serve as an indicator and solid first step towards a better understanding of near-field rocket exhaust plume chemistry and could potentially also be used to validate numerical models.
How to cite: Lober, L., Knapp, B., and Hardi, J.: Towards Determining OH*, CH* and C2* Concentrations in LOX/Methane Rocket Engine Tests via Emission Spectroscopy as a Potential Means to Assess Climate Impact, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11387, https://doi.org/10.5194/egusphere-egu26-11387, 2026.
Posters on site: Fri, 8 May, 14:00–15:45 | Hall X5
As part of ESA’s Green Agenda, the Agency is committed to driving the design of space products and services towards minimising environmental impacts across their entire life cycle. With the rapidly increasing frequency of satellite launches and spacecraft re-entries, robust assessment of their atmospheric and environmental consequences has become a critical scientific priority.
This presentation emphasises the importance of acquiring real-world observational data and advancing our understanding of the chemical and physical processes associated with spacecraft launch and re-entry emissions. Recent studies indicate that anthropogenic metal emissions from spacecraft re-entry may become a significant contributor to the stratospheric particle burden, in some cases approaching the natural meteoritic influx for specific elements. Observations from high-altitude aircraft and ground-based facilities have already identified metal-rich aerosols in the stratosphere, raising concerns regarding their roles in cloud formation, radiative forcing, ozone depletion, and broader atmospheric chemistry.
The presentation addresses key scientific, engineering, and environmental challenges related to spacecraft launch and re-entry, including the initiatives of the Atmospheric Impacts of Re-entry and Launch (AIRL) working group, ESA’s targeted measurement campaigns, and ongoing and future research opportunities. It highlights the need for coordinated, cross-disciplinary approaches that integrate observations, laboratory studies, and modelling. As space activities continue to accelerate, sustained upper-atmosphere research and science-driven policy development are increasingly essential. This presentation highlights ESA’s initiatives in responding to these challenges, reinforcing the need of atmospheric impact assessment in shaping the future of sustainable space operations.
How to cite: Mitchell, A.: Understanding the Atmospheric Effects of Spacecraft Re-entry, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7192, https://doi.org/10.5194/egusphere-egu26-7192, 2026.
A crucial input to the scientific study of anthropgenic effects on the upper
atmosphere is a reliable inventory of reentering objects. Some studies
have relied on the US Space Force catalog as a finding list for reentries,
but it is severely incomplete as it does not include objects which stay in
space for less than a few orbits. The General Catalog of Space Objects
(planet4589.org) includes an `auxiliary catalog' which adds these missing
objects, mostly launch vehicle upper stages. For the past three years
the catalog has been enhanced to include approximate reentry locations,
mostly based on NOTAM and similar warning area notifications, permitting
a spatially dependent assesment of the input reentry flux; the study
by Barker, Marais and McDowell (2024) has made use of this data.
I will discuss some features of the catalog as well as its limitations.
How to cite: McDowell, J.: Updating the inventory of spacecraft reentries: challenges and limitations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7304, https://doi.org/10.5194/egusphere-egu26-7304, 2026.
The developments rapidly (and alarmingly) playing out in low-Earth orbit (LEO) are significantly affecting aspects of radio astronomy, nighttime ground-based astronomy, space weather remote sensing, space physics, solar observing, and access to space itself. It is suggested that space-involved organizations should step in to promote actions to regulate the nearly $400 billion space industry that presently is operating in a Wild West , essentially unregulated, fashion due to the inadequacy of current licensing and launch practices. Many forums have provided compelling evidence from scientists and engineers about the interference that communications spacecraft are having on research programs. When the added—and extremely concerning—consequences of exponentiating orbital debris associated with satellite launches and collisions are folded in, we are seeing the equivalent of Garrett Hardin’s “Tragedy of the Commons” in near-Earth space (Science, 1968). It is enticing to citizens world-wide to have low-priced, essentially global, and unfettered communications. However, this is coming at a significant cost to science in our cosmic “backyard”. If satellites continue to increase in number and attendant debris continues to fill bands around Earth, it will soon be nearly impossible to observe the universe beyond our planet with ground-based telescopes or even safely launch and operate scientific satellites in LEO. What is quite clear is that the uncontrolled and unregulated flooding of LEO now is encouraging further players to do the same as what the U.S. is doing. This will not ‘self-regulate’ for economic reasons: an earlier 2021 NSF-funded study by the JASON committee, titled “The Impacts of Large Constellations of Satellites”, found that the perceived and persistent positive economic payoff return vs. investment cost would not limit the rapid deployment trend even beyond 100,000 satellites. Until the problems and dangers of the populating LEO are better understood and until mitigation is possible, research bodies should be insisting that governments (as well as non-government players) be constrained from carrying out more massive launches. It would be hoped that this presentation will allow an examination of the issues and will lead to productive discussion of policy approached that can help address the growing problem including:
- Regulatory Framework and Governance
- Sustainability of Satellite Operations
- Astronomical Obscuration
- Radio Astronomy Interference
- Satellite Collisions and Orbital Debris
- International Cooperation and Coordination
How to cite: Baker, D. N.: Sustaining the Future in Low Earth Orbit, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8240, https://doi.org/10.5194/egusphere-egu26-8240, 2026.
Both metals from meteoroids and metals from the reentry of rocket boosters and satellites are incorporated into natural sulfuric acid particles in the stratosphere. Numerous elements from both meteoroids and spacecraft reentry have been measured in stratospheric particles.
In many cases, the measurements can separate how much of a given metal came from meteoroids and how much from spacecraft. These data provide constraints on both the amounts of ablated metals and the ablation process. For example, the aluminum to iron ratio in particles from meteors constrains the ablation fraction for aluminum. The amounts of metals from spacecraft can be compared to an inventory of the composition of objects re-entering the atmosphere.
How to cite: Murphy, D., Schill, G., and Lawler, M.: Spacecraft, Ablation Processes, and Metals in the Stratosphere, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8332, https://doi.org/10.5194/egusphere-egu26-8332, 2026.
The influx of anthropogenic metals into the atmosphere is expected to increase substantially due to the rapid growth of the space industry. More than 20 elements from re-entering spacecraft have been identified in sulphuric acid droplets in the Junge layer, with several estimated to surpass the background level from cosmic dust. While the atmospheric impact of these particles is uncertain, they have been widely hypothesised, including ozone destruction, increased polar stratospheric cloud formation, harmful surface deposition, a perturbed radiative balance and in turn, changes to global circulation.
The spacecraft ablation process and subsequent formation of space debris particles (SDPs) are not well defined. The dominant constituent of spacecraft is aluminium. If vaporised, aluminium is expected to undergo a series of reactions to form aluminium hydroxide (Al(OH)3). The initial form and size of the particles will strongly influence the coagulation, global transport, and atmospheric lifetime of the particles. Constraining these factors is vital to accurately assessing the impact SDPs have on the atmosphere.
This work provides an update on the work presented at EGU2025 (Egan et al., Modelling impacts of ablated space debris on atmospheric aerosols, EGU25-4460), using the Whole Atmosphere Community Climate Model with the Community Aerosol and Radiation Model for Atmospheres (WACCM-CARMA) to simulate the production and transport of SDPs. This work investigates the sensitivity of the initial particle radius to the transport, lifetime and surface deposition of particles.
How to cite: Hawkins, S., Egan, J., Plane, J., Marsh, D., and Feng, W.: Modelling the transport of ablated space debris particles in the atmosphere, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19003, https://doi.org/10.5194/egusphere-egu26-19003, 2026.
Deployment of satellite megaconstellations has led to unprecedented growth in the space industry, with record launch rates and anthropogenic mass re-entering the Earth’s atmosphere in 2025. These activities uniquely release air pollutant emissions throughout all atmospheric layers, leading to long lifetimes in upper atmospheric layers where turnover rates are very slow. A growing number of recent studies have highlighted the potential of these emissions to result in extremely effective stratospheric ozone depletion and radiative forcing. With rocket launch emissions in the satellite megaconstellation era (2020-present) now dwarfing those of the 20ᵗʰ century, there is an ever greater need to quantify space industry emissions across the space age. We previously published a 3-D, global inventory of space industry emissions for the megaconstellation era (2020-2022), categorized by whether the launch contained megaconstellation payloads. This inventory, designed for input to global chemistry-climate models, included black carbon (BC), nitrogen oxides (NOx≡NO+NO2), water vapour (H2O), carbon monoxide (CO), alumina aerosol (Al2O3) and chlorine species (Cly≡HCl+Cl2+Cl) from rocket launches and nitrogen oxides (NOx≡NO) and oxidized alumina (AlOx) from re-entries. Here we present a significant expansion to our inventory to cover the entirety of the space age (1957-present), demonstrating significant increases in recent rocket launch and re-entry emissions since 2020. We also introduce new emission species from re-entry (BC, HCl, Cl) and present an online platform to visualise the growth in space industry emissions (https://cbarker211.github.io/). We will use our historical emissions data to drive the calculation of future pathways for the space industry, presenting business-as-usual, conservative, and high-growth scenarios. We will also implement our updated geolocated emissions into the GEOS-Chem 3-D model of atmospheric composition coupled to a radiative transfer model to assess the long-term impacts on ozone and climate.
How to cite: Barker, C. and Marais, E.: Tracking Rocket Launch and Spacecraft Re-entry Emissions Across the Space Age, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19738, https://doi.org/10.5194/egusphere-egu26-19738, 2026.
A global three-dimensional Lagrangian chemistry-transport model (STOCHEM-CRI) is employed to describe the impact of space rocket exhaust NOx emissions on the global distributions of methane (CH4) and tropospheric ozone (O3), the second and third most man-made greenhouse gases after carbon dioxide (CO2). Tropospheric column NOx emissions have been injected above key active launch sites with One-At-A-Time (OAT) sensitivity experiments producing global warming potentials (GWP) for short- and long-term ozone as well as long term methane GWP contributions. A sensitivity to launch location and timing is observed, opening future work for potential mitigation strategies. Although current impacts of space rocket launch on global distributions of CH4 and O3 are small, future challenges exist with increasing launch cadence requiring further controlling of NOx emissions into the future to avoid further impacts on GWP.
How to cite: Walsh, A., Bullock, S., Shallcross, D., Hanna, S., Derwent, D., and Khan, A.: Rocket launch tropospheric NOx emission: Impact on ozone and methane concentrations and launch location sensitivity., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19631, https://doi.org/10.5194/egusphere-egu26-19631, 2026.
The rapid growth of space-related activities over the past decade has prompted increasing attention to their potential environmental impacts, particularly those associated with launch and atmospheric re-entry events. These processes release high-temperature gases laden with solid and liquid particles spanning a wide size range—from nanometric to millimetric—across a broad spectrum of altitudes. Despite their potential relevance to atmospheric chemistry, radiative balance, and long-term sustainability of space operations, the physical and chemical impacts of such particles on the atmosphere remain poorly understood due to the scarcity of dedicated experimental data.
To address this gap, the German Aerospace Center (DLR) is conducting a multidisciplinary research effort aimed at assessing the atmospheric impact of space activities. Within this framework, the Supersonic and Hypersonic Technologies Department in Cologne is developing a particle collection system certified for high-enthalpy environments. The collector is intended to enable in-situ sampling of particles generated by rocket motor exhausts as well as by material ablation during hypersonic flight and atmospheric re-entry. Subsequent post-flight laboratory analyses of the collected samples will support the generation of a comprehensive dataset, contributing to a deeper understanding of particle properties and their implications for environmental sustainability.
Experimental investigations of particle-laden high-enthalpy flows have been carried out at the arc-heated wind tunnel L2K and in the vertical test section VMK in Cologne. A combination of intrusive and non-intrusive diagnostic techniques has been employed to characterize suspended particulate matter. The L2K facility has been used to study particle-laden flows in CO₂ atmosphere, while the VMK facility has focused on assessing the environmental impact of small-scale solid rocket motors.
This contribution presents recent progress and remaining experimental challenges in the design of a high-enthalpy particle collector, alongside the current state of the art in multiphase flow diagnostics within the department. The methodologies and findings discussed are also relevant to planetary science applications and may, in the future, be extended to the characterization of Martian atmospheric entry conditions, including scenarios involving global dust storms.
How to cite: Salvi, C. and Gülhan, A.: Particle Collection in High-Enthalpy Supersonic Flows: Objectives and Challenges, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12400, https://doi.org/10.5194/egusphere-egu26-12400, 2026.
The planned deployment of satellite mega-constellations will substantially increase the flux of anthropogenic space debris re-entering Earth’s atmosphere. A large fraction of this material is composed of aluminum, which will ablate during re-entry and form aluminum oxide (Al2O3) containing aerosols in the mesosphere and lower thermosphere. These particles represent a new, human-made metal aerosol source that may interact with natural meteoric smoke and potentially impact upper-and middle- atmospheric chemistry, radiative balance, polar mesospheric cloud, polar stratospheric cloud as well as stratospheric aerosol formation. However, observational constraints on the abundance and vertical distribution of such aluminum-bearing aerosols are currently very limited.
Aluminum oxide exhibits characteristic spectral features in the mid-infrared, allowing detection via remote sensing spectroscopic measurements. In contrast to techniques based on scattering in the visible wavelength range, mid-infrared spectroscopic detection is independent of particle size as long as the particle radius remains small compared to the wavelength. This makes it particularly suited to constraining nanometer- to sub-micrometer-sized aluminum oxide aerosols expected from debris ablation. Moreover, spectrally resolved infrared limb measurements enable the quantification of total aerosol volume (and thus mass) profiles, providing a direct link between observed aerosol burdens and modeled debris input fluxes.
In this work, we quantitatively assess the capability of a space-borne infrared limb-imaging instrument to detect and characterize aluminum oxide aerosols from re-entering space debris. We perform end-to-end simulations of atmospheric radiances and instrument response in the mid-infrared, incorporating realistic Al2O3 optical properties and assumed vertical profiles derived from debris model scenarios associated with upcoming mega-constellations. Radiative transfer calculations are used to compute infrared limb-emission spectra and sensitivities, which are then passed through an instrument simulator system representative of the CAIRT (Changing-Atmosphere Infra-Red Tomography) limb-imaging mission concept, studied as an EE11 candidate for ESA’s Earth Explorer program.
We demonstrate that the characteristic mid-infrared absorption features of aluminum oxide remain detectable at realistic noise levels for CAIRT-like performance, over a range of plausible aerosol loads. Sensitivity analyses show that vertical profiles of total Al2O3 aerosol volume can be retrieved, even when particle sizes and shapes are not well constrained. Our results indicate that a CAIRT-type infrared limb-sounding mission could provide the first global, vertically resolved observational constraints on aluminum oxide aerosols from space debris.
How to cite: Höpfner, M., Funke, B., Sinnhuber, B.-M., Errera, Q., Friedl-Vallon, F., Hoffmann, A., Preusse, P., and Ungermann, J.: Potential detection and quantification of aluminum oxide aerosols from space debris via infrared limb-emission sounding, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13101, https://doi.org/10.5194/egusphere-egu26-13101, 2026.
The rapid growth of orbital launch activity continued in 2024, marking the fourth consecutive year of record-breaking launch rates. Since 2019, the annual number of launches has more than doubled, with total propellant mass burned increasing even more strongly. This trend underscores the need for quantitative assessments of rocket emissions and their impacts on atmospheric chemistry, ozone, and climate.
We present the DLR Inventory of Global Emissions by Launchers 2024, a global, four-dimensional dataset describing direct exhaust from all orbital launches conducted in 2024. The inventory provides spatially and vertically resolved exhaust across all affected atmospheric layers and is designed for direct use in global chemistry–climate models.
All launch systems contributing at least 0.5% of the total propellant burned in 2024 are individually reconstructed and simulated, including Ariane 62, multiple Long March variants, Falcon 9, Starship, Soyuz, and other major systems. Detailed aerodynamic, mass, and engine models capture thrust profiles, engine exhaust, staging, and mass properties for the launchers. This enables estimates of key exhaust species such as CO₂, H₂O, chlorine compounds, and black carbon. The three-dimensional exhaust profiles for the pollutants are derived from ascent and booster return trajectories that are optimized for each individual launch. Smaller systems are represented using surrogate models that preserve propellant mass and engine type.
The DLR Inventory of Global Emissions by Launchers 2024 provides a consistent basis for assessing the growing role of spaceflight emissions in the Earth system. In the coming years, as part of the S3D-BETTER project the inventory will be further improved by adding early plume and intermediate plume simulations and it will be extended to a longer timeframe. Furthermore, it will be used by the DLR Institute of Atmospheric Physics to estimate the climate and ozone impact of launch emissions.
Beyond its role within S3D-BETTER, the inventory will be made publicly available and its use by other projects and institutions is explicitly encouraged.
How to cite: Herberhold, M., Wilken, J., Callsen, S., and Sippel, M.: DLR Inventory of Global Emissions by Launchers 2024, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16722, https://doi.org/10.5194/egusphere-egu26-16722, 2026.
