It could spell bad news for the ozone layer in particular. Aluminum oxide, for example, is a by-product of the oxidation during re-entry of aluminum-based spacecraft components, says José Ferreira, an aerospace engineer at the University of Southern California in Los Angeles. “And we know that aluminum oxides are catalysts for ozone depletion.”
This new threat to the ozone layer is particularly frustrating in the wake of the success of the Montreal Protocol, a 1987 agreement to ban the production and emissions of known ozone-destroying chemicals (SN: 2/10/21). By 2016, the annual hole in the ozone layer that forms over Antarctica was already showing signs of healing, on track to completely close up within about 50 years (SN: 12/14/16).
There are myriad other ways that spacecraft pollutants might tinker with the atmosphere’s complex chemical brew, Murphy says. Soot emitted from rocket engines absorbs solar energy, which can warm the atmosphere. Copper and other metals released during the incineration of spacecraft wiring and alloys are known to be powerful catalysts for chemical reactions in the atmosphere. Among other things, those metals could promote the creation of the tiny particles that act as the seeds of clouds.
There’s not much direct information on which of these reactions might already be happening. The data that do exist are destined for computer simulations that track the life cycle of these pollutants and their interactions in the atmosphere. Murpyh’s team is planning more flights in 2025 to continue tracking the growing inventory of spacecraft debris.
If you can't use units correctly, no one is going to take you seriously. 5.6 billion grams is just 5,600 tons (or 5.6 kilotons if I want to eat my own dogfood). With a F9 launch capable of putting...
Emissions of aluminum and nitrogen oxides from satellite reentries nearly doubled from 3.3 billion grams in 2020 to 5.6 billion grams in 2022
If you can't use units correctly, no one is going to take you seriously. 5.6 billion grams is just 5,600 tons (or 5.6 kilotons if I want to eat my own dogfood). With a F9 launch capable of putting 13,100 kg in LEO, and 87 launches in 2023, that's 1.139ktons if all of them fell right now.
I feel like this article is more rage-bait than science.
The study the author is referencing specifically uses Gg (gigagrams) as the unit of mass, so presumably it is the scientifically "correct" unit to use. She simply translated the Gg values into...
The study the author is referencing specifically uses Gg (gigagrams) as the unit of mass, so presumably it is the scientifically "correct" unit to use. She simply translated the Gg values into "billion grams" (which a gigagram is), likely to make it a bit easier for readers to understand.
There are close to 6000 megaconstellation satellites in low-Earth orbit comprising 65% of all satellites orbiting Earth. The growth in satellite megaconstellations has driven surges in rocket launches and re-entry destruction of spent satellites. This has contributed to large increases in emissions of pollutants that are very effective at depleting stratospheric ozone and altering climate, due to direct injection of pollutants into the upper layers of the atmosphere where turnover rates are very slow. An additional 540,000 megaconstellation satellites are proposed, yet the environmental impacts of emissions from current and future satellite megaconstellations remain uncharacterized and unregulated. Here we calculate emissions of the dominant pollutants from megaconstellation and non-megaconstellation rocket launches and re-entries from 2020 to 2022 to determine the effect on climate and stratospheric ozone. Pollutants include 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 alumina aerosol (Al2O3) from re-entries. Launch emissions are calculated by determining the vertical distribution of propellant consumption for each rocket stage and calculating and applying vertically resolved propellant specific emission indices that account for additional oxidation in the hot rocket plume and changes in atmospheric composition with altitude. To quantify the re-entry emissions, the mass of re-entering objects is compiled for all objects (spacecraft, rocket stages, fairings, and components) re-entering Earth’s atmosphere in 2020-2022. Many objects, accounting for 12-16% of re-entry mass, are not geolocated, so the longitude and latitude of re-entry is bounded by the reported orbital inclination. Object class and object reusability are used to define the chemical composition and mass ablation profile of each re-entering object. We find that total propellant consumed has nearly doubled from ~38 Gg in 2020 to ~67 Gg in 2022 and re-entry mass has increased from ~3.3 Gg in 2020 to ~5.6 Gg in 2022. Megaconstellation re-entries accounted for 8-12% of the Al2O3 and NOx re-entry emissions in 2020-2022, due to increased megaconstellation launches and short (~2 years) lifespan of most (85%) megaconstellation satellites. Anthropogenic re-entry emissions of NOx (~4.2 Gg) and Al2O3 (~0.96 Gg) in 2022 equal a third of the natural meteoritic injection of NOx and surpass the natural injection by 7 times for Al2O3. The annual emissions for 2020-2022 will be used to predict the rise in emissions up to 2029 from megaconstellation and non-megaconstellation rocket launches and object re-entries for input to the 3D atmospheric chemistry transport model GEOS-Chem coupled to a radiative transfer model to simulate stratospheric ozone depletion and radiative forcing attributable to a decade of satellite megaconstellation emissions.
The study's authors are Connor R. Barker, a PhD Research Fellow in Atmospheric Chemistry and Physical Geography at University College London, Eloise Marais, a Professor of Atmospheric Chemistry...
The study's authors are Connor R. Barker, a PhD Research Fellow in Atmospheric Chemistry and Physical Geography at University College London, Eloise Marais, a Professor of Atmospheric Chemistry and Air Quality at University College London, and Jonathan McDowell, an astronomer and astrophysicist at the Harvard–Smithsonian Center for Astrophysics's Chandra X-ray Center.
So I assume they would know the correct units to use when studying these sorts of things. But I am not a scientist myself, so ¯\_(ツ)_/¯.
Don't forget to include the second stage in the delivery to LEO. What I haven't seen mentioned yet is how much un-burnt propellant is injected into the high atmosphere through venting, MECO and...
Don't forget to include the second stage in the delivery to LEO. What I haven't seen mentioned yet is how much un-burnt propellant is injected into the high atmosphere through venting, MECO and second stage startup? Those turbopumps dont turn on and off like a light switch, they need propellant flowing through them before they ignite and the propellant will keep flowing for a bit when they turn off. When you watch the launch you can see clouds being emitted. On a F9 the clouds are either kerosene or oxygen. Is it a tablespoon or 1000 gallons? What does kerosene do to the upper atmosphere? What about methane?
It’s cool that they found a way to measure this. Here’s another article from Scientific American that adds a bit of context: Other material likely comes from volcanic eruptions and meteors. Here...
It’s cool that they found a way to measure this. Here’s another article from Scientific American that adds a bit of context:
Although only about 10 percent of the sampled sulfuric acid particles contained spacecraft-sourced metals, the researchers forecast that value could grow to 50 percent or more in the coming decades because of skyrocketing numbers of launches and satellites.
Other material likely comes from volcanic eruptions and meteors. Here is a Russian paper about a correlation between the ozone layer and meteor showers:
Satellite launches would be supplementing the natural mix with an artificial mix.
I wonder if there are any beneficial materials that would be helpful for the ozone layer? Perhaps SpaceX could be convinced to launch more of those materials as part of their satellites?
If you can't use units correctly, no one is going to take you seriously. 5.6 billion grams is just 5,600 tons (or 5.6 kilotons if I want to eat my own dogfood). With a F9 launch capable of putting 13,100 kg in LEO, and 87 launches in 2023, that's 1.139ktons if all of them fell right now.
I feel like this article is more rage-bait than science.
The study the author is referencing specifically uses Gg (gigagrams) as the unit of mass, so presumably it is the scientifically "correct" unit to use. She simply translated the Gg values into "billion grams" (which a gigagram is), likely to make it a bit easier for readers to understand.
Developing inventories of by-products from satellite megaconstellation launches and disposal to determine the influence on stratospheric ozone and climate
I'm sure the scientifically accurate measure is ppm, but whatever.
The study's authors are Connor R. Barker, a PhD Research Fellow in Atmospheric Chemistry and Physical Geography at University College London, Eloise Marais, a Professor of Atmospheric Chemistry and Air Quality at University College London, and Jonathan McDowell, an astronomer and astrophysicist at the Harvard–Smithsonian Center for Astrophysics's Chandra X-ray Center.
So I assume they would know the correct units to use when studying these sorts of things. But I am not a scientist myself, so ¯\_(ツ)_/¯.
Don't forget to include the second stage in the delivery to LEO. What I haven't seen mentioned yet is how much un-burnt propellant is injected into the high atmosphere through venting, MECO and second stage startup? Those turbopumps dont turn on and off like a light switch, they need propellant flowing through them before they ignite and the propellant will keep flowing for a bit when they turn off. When you watch the launch you can see clouds being emitted. On a F9 the clouds are either kerosene or oxygen. Is it a tablespoon or 1000 gallons? What does kerosene do to the upper atmosphere? What about methane?
It’s cool that they found a way to measure this. Here’s another article from Scientific American that adds a bit of context:
Other material likely comes from volcanic eruptions and meteors. Here is a Russian paper about a correlation between the ozone layer and meteor showers:
The Effect of Major Meteor Streams on the Total Ozone in the Earth's Atmosphere
Satellite launches would be supplementing the natural mix with an artificial mix.
I wonder if there are any beneficial materials that would be helpful for the ozone layer? Perhaps SpaceX could be convinced to launch more of those materials as part of their satellites?
Link to a presentation by the study authors:
https://maraisresearchgroup.co.uk/Presentations/BarkerC-Southampton-workshop-2024.pdf