Emissions of Black Carbon by Rockets  (or "A Tale of Two Boulders")
"...a terrific win for us" - but at what cost to the environment?

"...fuel which provides none of the toxins that are present in the solid rockets used by the Space Shuttle and satellite launches. Less fuel and clean fuel all adds up to a space launch system which would be completely unprecedented in its low environmental impact." (Virgin Galactic, June 11, 2009)

"The Sierra Nevada Corporation (SNC) Space Systems Group announces the successful completion of two critical milestones for NASA’s Commercial Crew Development (CCDev) Program. On September 21, 2010, SNC completed three successful test firings of a single hybrid rocket motor in one day. "
(SNC Press Release, Oct. 11, 2010)

"If the space tourism industry matures to the point that 1,000 hybrid-powered suborbital flights depart annually, those trips would deposit roughly 600 metric tons of soot into the stratosphere each year. Over decades of launches, those emissions would form a persistent and asymmetric cloud over the northern hemisphere that could impact atmospheric circulation and regional temperatures far more than the greenhouse gases released into the stratosphere by those same flights."
(Scientific American,  October 23, 2010)

"[T]he rocket fuel that most companies plan to use -- a solid synthetic rubber that is burned with a liquid nitrous oxide -- creates far more soot than more standard rocket fuels that mix together hydrogen and oxygen."
(Boulder Daily Camera, October 25, 2010)

Boulder scientists will reach new heights on commercial spaceship.
"The scientists signed contracts last month with Virgin Galactic and XCOR Aerospace, two of the five private firms that have begun building aircraft to carry passengers on suborbital flights....the black smoke emissions of these vehicles is roughly one million times worse per kilogram for the stratosphere than the emission of carbon dioxide."
(Boulder Daily Camera, April 8, 2011)

"Sierra Nevada Corp. has been awarded $80 million to continue development of the Dream Chaser space plane by its Louisville-based space-systems group. The National Aeronautics and Space Administration announced Monday that Sierra Nevada is one of four companies working on space transportation concepts to split nearly $270 million. 'This is a terrific win for us,' said Mark Sirangelo, chairman of Sierra Nevada Space Systems. 'It validates our approach to not only the industry but our approach to the vehicle design.' "
(Denver Post, April 19, 2011)

So who is going to study the environmental impact...or do we just ignore it?
"The report is from a well respected source and looks at an area of potential environmental impact which is certainly important to study. However it is also an early stage, speculative discussion paper by and for the scientific research community. The lack of any real data and the many unknowns mean that the range of uncertainty in the models is enormous."
(Virgin Galactic, date of posting unknown, accessed May 31, 2011)

Other , less important news

Rockets and Future Ozone Depletion
"Increased international space launches and the potential commercial space travel boom could mean that rockets will soon emerge as the worst offenders in terms of ozone depletion, according to the study, published in the March issue of the journal Astropolitics." (National Geographic, April 14, 2009)

Low-Altitude Stratospheric Ozone Losses
"New findings by University of Colorado at Boulder researchers indicate ozone losses due to the breakdown of chlorofluorocarbons, or CFCs, occur much faster than previously believed at higher latitudes roughly 10 miles above Earth." (EurekAlert, May 28, 2002)