Speaker
Description
The billionaire space tourism launches by Virgin Galactic, Blue Origin and SpaceX in 2021 demonstrated the potential for a future space tourism industry. All these offerings produce chemical by-products during launch and re-entry that deplete stratospheric ozone and alter climate. We modelled the environmental impact that could result from sustained (3 years) rocket launches from a plausible future space tourism industry using the GEOS-Chem chemical transport model coupled to a radiative transfer model. The vertically resolved emissions inventory we constructed was based on the location and launch profiles of the demonstration missions and assumed daily suborbital launches by Virgin Galactic and Blue Origin and weekly orbital launches by SpaceX. All launches are in the northern hemisphere, so ozone loss from re-entry NOx emissions peaks in the springtime Arctic. According to GEOS-Chem, the most severe ozone loss of ~5 ppbv is in the upper stratosphere (~5 hPa) and accounts for almost 10% of the repair that has resulted from the global Montreal Protocol ban on Earth-bound ozone depleting substances. The global mean top-of-atmosphere radiative forcing due to black carbon emissions from SpaceX and Virgin Galactic flights is 3.4 mW m-2, which is ~3% of global radiative forcing of all BC sources. This is far greater than the contribution of these rocket launches to total global BC emissions of ~0.01%, as radiative forcing per mass unit emissions is ~500 times greater than that of Earth-bound sources. Since 2021, many more space tourism companies have been established. Regulation needs to be established to mitigate harm to the ozone layer and climate that are very sensitive to space tourism emissions.
