Scientists: Regulate Rocket Launches to Safeguard Ozone Layer

"As the rocket launch market grows, so will ozone-destroying rocket emissions," said Professor Darin Toohey of the Atmospheric and Oceanic Sciences Department at the University of Colorado, Boulder. "If left unregulated, rocket launches by the year 2050 could result in more ozone destruction than was ever realized by CFCs."

Future ozone losses from unregulated rocket launches will eventually exceed ozone losses due to chlorofluorocarbons, or CFCs, which stimulated the 1987 Montreal Protocol banning ozone-depleting chemicals, said Martin Ross, chief study author from The Aerospace Corporation in Los Angeles.

Proposed space activities would require frequent launches of large rockets over extended periods ot time, so the new study was designed to bring attention to the issue in hopes of triggering additional research, said Ross.

NASA launches a Shuttle into space. (Photo courtesy NASA)

"In the policy world uncertainty often leads to unnecessary regulation," he said. "We are suggesting this could be avoided with a more robust understanding of how rockets affect the ozone layer."

Each year, the hole in Earth's protective ozone layer over the Antarctic reaches its largest size during a period in September. The ozone layer over the Arctic is also thinning.

Since 1987, CFCs have been banned from use in aerosol cans, freezer refrigerants and air conditioners. Many scientists expect that by the year 2040 the stratospheric ozone layer will return to levels that existed prior to the use of ozone-depleting chemicals.

Current global rocket launches deplete the ozone layer by no more than a few hundredths of one percent annually, said Toohey. But as the space industry grows and other ozone-depleting chemicals decline in the Earth's stratosphere, the issue of ozone depletion from rocket launches is expected to move to the forefront.

Today, just a handful of NASA space shuttle launches release more ozone-depleting substances in the stratosphere than the entire annual use of CFC-based medical inhalers used to treat asthma and other diseases in the United States and which are now banned, said Toohey.

"The Montreal Protocol has left out the space industry, which could have been included," he said.

Rocket combustion products are the only human sources of ozone-destroying compounds injected directly into the middle and upper stratosphere where the ozone layer resides, Toohey said.

Although U.S. science agencies spent millions of dollars to assess the ozone loss potential from a hypothetical fleet of 500 supersonic aircraft - a fleet that never materialized - much less research has been done to understand the potential effects the existing global fleet of rockets might have on the ozone layer, said Ross.

The stratospheric ozone layer absorbs more than 90 percent of the Sun's ultraviolet radiation that can harm humans and ecosystems if it reaches the Earth's surface.

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