Virgin Galactic are about to inaugurate their private flights to the edge of space, with the opening of their Spaceport America at Las Cruces, New Mexico, but some people are questioning the effect of soot emissions from rocket launches and its effect on global warming.
According to Nature.com, a report in the Geophysical Research Letters by Martin Ross and his colleagues from The Aerospace Corporation in El Segundo, California, found that the black carbon soot from a decade of commercial space launches will cause as much global warming as from current global aviation. The research explained that 1,000 private rocket launches annually could potentially place soot in a stratosphere layer at 40 kilometers (25 miles) altitude, which is three times higher than airline traffic. This soot could alter global atmospheric circulation and ozone, increasing polar surface temperatures by 1°C, and reduce polar sea ice by 5–15% due to the soot particles absorbing sunlight.
Both NASA and The Whitehouse are encouraging private enterprise to get into the launch business with almost US$1.6 billion of funding to take astronauts and cargo into orbit. Virgin Galactic is likely to be the first private space tour operator and could soon be making two launches a day from Spaceport America.
While most rocket launches use kerosene and liquid oxygen, or hydrogen and oxygen, many boosters use exotic fuels that are highly polluting such as hydrocarbon fuels with nitrous oxide. At lower altitudes, the contaminant particles from coal-plants and aircraft are removed from the atmosphere by rain and weather systems but at higher altitudes they stay in the stratosphere for 3 to 10 years according to the report.
"The response of the climate system to a relatively small input of black carbon is surprising," says Michael Mills of the National Center for Atmospheric Research in Boulder, Colorado, a study coauthor. “…and our results show particular climate system sensitivity to the type of particles that rockets emit.”