ROCKETS AND OZONE DEPLETION

[Lenny Siegel <lsiegel@igc.org>]

From: Lenny Siegel <lsiegel@igc.org>

ROCKETS AND OZONE DEPLETION
The Air Force continues to probe the impact of solid rocket launches, 
such as its own Titan IV and NASA's Space Shuttle boosters, on the 
ozone layer. Its contractor, the Aerospace Corporation, published a 
scientific report this March reinforcing models suggesting that 
stratospheric emissions from solid motors directly catalyze ozone depletion.
Specificially, laboratory simulations of solid rocket motor 
afterburning showed that a significant fraction of the hydrogen 
chloride (HCl) released by the rockets' primary burn is broken down by 
afterburning, and that the chlorine thus liberated "ends ups almost 
exclusively in the form of Cl2 [the chlorine molecule]." The study 
warns that while "gaseous HCl is inert toward ozone and is slow to 
photodisssociate in the stratosphere, ... Cl2 (which rapidly 
photodissociates), Cl atoms, or ClO may readily contribute to ozone 
destruction cycles."
M.L. Burke and P.F. Zittel, "Laboratory Generation of Free Chlorine 
from HCl Under Stratospheric Afterburning Conditions," The Aerospace 
Corporation [TR-96(1306)-3], March 1, 1996, prepared for Space and 
Missile Systems Center, Air Force Materiel Command (SMC-TR-96-10).
Lenny Siegel