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Global atmospheric response to emissions from a proposed reusable space launch system

Modern reusable launch vehicle technology may allow high flight rate space transportation at low cost. Emissions associated with a hydrogen fueled reusable rocket system are modeled based on the launch requirements of developing a space‐based solar power system that generates present‐day global electric energy demand. Flight rates from 104 to 106 per year are simulated and sustained to a quasisteady state. For the assumed rocket engine, H2O and NOX are the primary emission products; this also includes NOX produced during reentry heating. For a base case of 105 flights per year, global stratospheric and mesospheric water vapor increase by approximately 10 and 100%, respectively. As a result, high‐latitude cloudiness increases in the lower stratosphere and near the mesopause by as much as 20%. Increased water vapor also results in global effective radiative forcing of about 0.03 W/m2. NOX produced during reentry exceeds meteoritic production by more than an order of magnitude, and along with in situ stratospheric emissions, results in a 0.5% loss of the globally averaged ozone column, with column losses in the polar regions exceeding 2%.