ago in the Phoenix suburb of Glendale, and two of those guns were used in the shootout that took Terry's life. His letter didn't elaborate on the possible role of federal agents in the sale of the guns, and it couldn't be determined if the purchases were part of a sting operation.after the start of the space age, peaking at 157 launches in 1967. But then it declined over the next 4 decades, decreasing to only 42 launches in 2005. So for most of the past half century, rocket emissions have been in decline and therefore were not of much interest to researchers working to understand the most significant aspects of climate change and ozone depletion.

But that historic trend reversed in 2005 and, despite the retirement of the Space Shuttle in 2011, launch numbers began rising again. With 114 launches in 2018, the number of launches has been growing at an average rate of about 8% per year for the past decade. Rocket emissions have also been growing, faster than global emissions from other sources with comparable impacts, such