newman@cdc910b21.gsfc.nasa.gov (P.A. Newman) (08/09/90)
On 6 Aug 90 mmm@cup.portal.com (Mark Robert Thorson) wrote: >The current issue of Buzzworm, an "environmental journal" has a short article >on page 14 describing the pollution effects of the space shuttle. Quoting >from vol 2 no 4 (probably one of the last issues of this high-overhead glossy >rag): > ... >Huh? Could any of these figures possibly be true? If Space Shuttle >launches might cause 10% or even 1% of the ozone problem, that seems >like a serious cause for concern! I rather suspect somebody must have >slipped a few digits in reporting this story. Can somebody please provide >some real numbers on how much the Space Shuttle contributes to the ozone >problem. ************************** I talked to Charlie Jackman (one of the authors of the above quoted study) and his response follows: ************************** The atmospheric modelling study of the space shuttle effects on the stratosphere involved three independent theoretical groups, and was organized by Dr. Michael Prather, NASA/Goddard Institute for Space Studies. The three groups involved Michael Prather and Maria Garcia (NASA/GISS), Charlie Jackman and Anne Douglass (NASA/Goddard Space Flight Center), and Malcolm Ko and Dak Sze (Atmospheric and Environmental Research, Inc.). The effort was to look at the effects of the space shuttle and Titan rockets on the stratosphere. The following are the estimated sources of stratospheric chlorine: Industrial sources: 300,000,000 kilograms/year Natural sources: 75,000,000 kilograms/year Shuttle sources: 725,000 kilograms/year The shuttle source assumes 9 space shuttles and 6 Titan rockets are launched yearly. Thus the launches would add less than 0.25% to the total stratospheric chlorine sources. The effect on ozone is minimal: global yearly average total ozone would be decreased by 0.0065%. This is much less than total ozone variability associated with volcanic activity and solar flares. The influence of human-made chlorine products on ozone is computed by atmospheric model calculations to be a 1% decrease in globally averaged ozone between 1980 and 1990. The influence of the space shuttle and Titan rockets on the stratosphere is negligible. The launch schedule of the Space Shuttle and Titan rockets would need to be increased by over a factor of a hundred in order to have about the same effect on ozone as our increases in industrial halocarbons do at the present time. Theoretical results of this study will be published in the Journal of Geophysical Research in the next few months in the paper "The Impact of the Space Shuttle on Stratospheric Chemistry and Ozone" by M. J. Prather, M. M. Garcia, A. R. Douglass, C. H. Jackman, M. K. W. Ko, and N. D. Sze. Charles Jackman, Atmospheric Chemistry and Dynamics Branch, Code 916, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 *********************** P. A. Newman Code 916 NASA/GSFC
tneff@bfmny0.BFM.COM (Tom Neff) (08/20/90)
Two other reasons why MORE articles about the shuttle ozone layer issue
haven't appeared here:
* It's summer, in fact August, and volume is down overall because a lot
of people are off the net.
* Discussions like that belong, if at all, in sci.space. People aren't
used to reading or posting ordinary blather here.
The user who wondered whether we were "ignoring something away here" may
be guilty of confusing the net with Something Important.
--
Canada -- a few acres of snow. ^v^v^ Tom Neff
-- Voltaire v^v^v tneff@bfmny0.BFM.COM