Global Atmospheric Response to Emissions from a Proposed Reusable Space Launch System

Reusable launch vehicles using combined cycle rocket engines could permit 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 of 10⁴, 10⁵, and 10⁶ yr^-1 are simulated and sustained to a quasi-steady state. For the assumed rocket engine, H₂O and NO_X are the primary emission products; this also includes NO_X produced during reentry heating. For a base case of 10⁵ flights yr^-1, 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. NO_X produced during reentry exceeds meteoritic production by more than an order of magnitude, and along with in situ stratospheric emissions, results in loss of the globally averaged ozone column by 0.5%, with column losses in the polar regions exceeding 2%.