Speaker
Description
The large-scale impacts of emissions from increasing numbers of launches to Low Earth Orbit (LEO) can be robustly modeled in high-top Earth System Models with interactive composition. Emissions vary as a function of fuel type used and impacts scale with the projected launch rate per year. For plausible values of rocket engine emission parameters, scenarios with ~1000 launches/yr, stratospheric temperature, humidity and ozone impacts are detectable, and at a conceivable 10,000 launches/yr, impacts are very significant. The dominant term regardless of fuel type is likely to be the impact of black carbon (soot) emissions which are poorly understood. Impacts of anticipated increases of re-entering orbital debris associated with large LEO constellations, can also be calculated within these models and will depend on the expected particle flux, composition and size distribution, interactions with the background sulfate layer, and substrate suitability for heterogenous chemistry. Direct radiative forcing from these aerosols will likely be small, but indirect effects on ozone could be significant. Better quantification of these effects will require constraints on plausible reentry scenarios, rocket plume chemistry and reentry vaporization debris characterization, which might be derived from lab experiments, remote sensing, and in situ sampling.
