Jango Fixit One issue that might deserve some attention has to do with the depletion of stratospheric ozone, a topic we discussed a few months back. Rocket engines emit reactive gases that cause ozone molecules to break apart. They also discharge microscopic particles of soot and aluminum oxide, which may increase the rate at which those gases wreak havoc. Each variety of rocket propellant delivers its own blend of ozone-depleting substances: Solid propellants, for example, are more damaging than liquid ones, though exactly how much is unclear. Engine design matters, too. To make matters worse, spacecraft dump some of these pollutants directly into the upper and middle stratosphere, where they can start causing damage immediately. Despite all this, spacecraft contribute very little to the global ozone problem. In a recent paper on the topic, researcher Martin Ross and three co-authors estimated that rocket launches are responsible for roughly 1 percent of the total ozone depletion that can be attributed to human causes. That percentage may rise, however, as more traditional pollutants, like CFCs, start to fade from the atmosphere (thanks to the 1987 Montreal Protocol). At the same time, the number of launches—for purposes of exploration, tourism, and space-based solar power (PDF)—is expected to increase. One of the studys co-authors has been quoted as saying, If left unregulated, rocket launches by the year 2050 could result in more ozone destruction than was ever realized by CFCs. slate/articles/health_and_science/the_green_lantern/2009/11/dirty_rockets.html
Posted on: Tue, 23 Sep 2014 02:15:03 +0000
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