Just when it looks as though people could breath a sigh of relief over the hole in stratospheric ozone over Antarctica -- it's expected to heal by 2050 -- scientists are raising a new ozone-related concern: rocket launches.
That's right. Rocket launches.
The idea is not as wiggy as it may sound. As early as 1974, some scientists had noted that the space shuttle -- still a gleam in NASA's eye at the time -- would be a source of chlorine emissions as it climbed through the atmosphere and passed through the stratosphere.
Chlorine-based compounds called chlorflorocarbons have been the main driver behind the loss of ozone in a high-altitude layer of the atmosphere called the stratosphere. They've been banned via the 1987 Montreal Protocol, along with other ozone-trashing compounds.
Indeed, some people have argued -- wrongly -- that the space shuttles have been responsible for the ozone hole.
For a team led by Martin Ross at the Aerospace Corporation in Los Angeles, it's not a question of today's launches being a problem. In a new research paper that appears in the on-line issue of the journal Astropolitics, he and his colleagues note that today's launch and reentry emissions are far too small to have a significant effect.
Down the road, however, the picture could change, especially if aerospace-industry launch projections pan out.