Rocket Launches and Satellite Re-Entry: Potential Issues and the Need for Additional Modeling and Measurements

The space industry is currently growing more rapidly than during any earlier time period since the beginning of the space age. Large low Earth orbit (LEO) satellite constellations and reusable liquid natural gas (LNG) fueled launch vehicles will change the scope and character of spaceflight. Satellite launches have increased four-fold in the past decade and are projected to grow even more quickly in coming decades. Given this explosive growth of the space industry, we need to understand combustion emissions from rockets and vaporization emissions from reentering space debris and how they will impact the global atmosphere. In particular, there may be changes to the stratospheric ozone chemistry as a result of space industry emissions into the middle atmosphere. At present, impacts are small, but evidence of metals that can only come from rocket stages and satellites have been detected in stratospheric aerosols, with an estimate that 10% of stratospheric aerosols contain species that can only originate from rocket stage/satellite ablation. Current rates of reentry particles are a few Gg/yr, but are projected to be over 10 Gg/year by 2030. Although modeled heating rates produced by reentry aluminum particles are small, they are statistically significant, and, as the number of objects in LEO are projected to increase, that impact will grow with time. Future work will attempt to estimate the impact of heterogeneous chemistry on reentry particles. Well quantifying impacts will require information on reentry scenarios, rocket plume chemistry and reentry vaporization debris characterization. Measurements, via laboratory experiments, remote sensing of launches and reentry, and in situ sampling are all needed to fully characterize space industry impacts on the atmosphere. This presentation will give an overview on what has been accomplished so far, and address what is needed to better characterize the impacts (and uncertainties) on the ozone layer from a growing space industry.