NASA SP-413 Space Settlements - Saint Ann's School

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NASA SP-413 — SPACE SETTLEMENTS — A Design Study
APPENDIX N
IMPACT OF EARTH LAUNCH VEHICLES
ON THE OZONE LAYER
Hydrogen chloride gas (HCl) produced from the exhaust of
the Space Shuttle booster motor (see fig. 4-29) dissociates to
produce free chlorine which, in turn, reacts to remove ozone
from the stratosphere by the following catalytic reactions:
Cl + O 3 → C1O + O 2
CIO + O → Cl + O 2
One-dimensional models of HCl deposition, vertical
transport, and chemical production and removal of
participating trace stratospheric constituents (OH, O, O( 1 D),
O 3 , CH 4 , H 2 , and NO) have been used by NASA to simulate
ozone depletion (refs. 45,46). Steady-state solutions were
obtained simulating 60 shuttle launches per year given that
the emissions were spread uniformly in the horizontal over a
hemisphere and over a 1000-km wide zone. The levels of
ozone reduction computed were about 0.3 percent and 1.0
percent, respectively. More recently, Whitten has revised
the ozone depletion calculation for the hemisphere
downward to less than 0.1 percent (personal
communication, July 1975). Launch rates that might be
anticipated for the initial colonization program are shown in
table 4-18.
The reduction in ozone concentration in the upper levels of
the atmosphere allows the molecular oxygen dissociating
radiation to penetrate lower before producing ozone; hence,
a primary effect is a downward shift in the ozone
distribution. A reduction in the total ozone concentration,
which would appear to be very minor, results only as a
secondary effect.
Advanced launch vehicles using liquid oxygen-liquid
hydrogen (LOX-LH 2 ) propellants above 30 km would
eliminate the emission of hydrogen chloride into the
stratosphere; however, there are also potential problems with
hydrogen fuel which produces water. Water is dissociated
as:
O( 1 D) + H 2 O → 2OH
in which the O( 1 D) results from ozone photolysis at
wavelengths shorter than 310 nm. The OH reacts with odd
oxygen in a catalytic cycle
OH + O 3 → HO 2 + O2
HO 2 + O → OH + O 2
However, compared to the 2 ppm of water in the
stratosphere, increases due to hydrogen combustion may be
negligible. Further study of the problem is required (R.
Whitten, NASA-Ames Research Center, personal
communication, August 1975).
REFERENCES
1. O’Neill, G. K.: The Colonization of Space, Physics
Today, vol. 27, no. 9, Sept. 1974, pp. 32-40.
2. von Braun, W.: Crossing the Last Frontier, Colliers, vol.
29, March 22, 1952, pp. 24-29.
3. Clarke, Arthur C.: Rendezvous with Rama, Ballantine
Books, New York, 1974.
4. Clarke, Arthur C.: 2001: A Space Odyssey, and
especially the movie “2001: A Space Odyssey,” directed
and produced by Stanley Kubrick. Script by Stanley
Kubrick and Arthur C. Clarke. Photography: Geoffrey
Unsworth. MGM, 1968. See also “Space Station V” in
the review of “2001” in Life Magazine, vol. 64, April, 5,
1968, pp. 24-33.
5. Timoshenko, S., and Woinowsky-Kreiger, S.: Theory of
Plates and Shells, 2nd ed., McGraw-Hill, New York,
1959.
6. Flugge, W.: Stresses in Shells, 2nd ed., Springer-Verlag,
New York, 1973.
7. Adapted from Dole, S. H.: Design Criteria for Rotating
Space Vehicles, The Rand Corporation, Santa Monica,
Oct. 1960, RM-2668.
8. Gray, H.: Rotating Vivarium Concept for Earth-like
Habitation in Space, Aerospace Medicine, vol. 42, Aug.
1971, p. 899; U.S. Patent 3,749,332 — July 31, 1973.
9. Tsiolkovsky, Konstantin E.: Issledovanie mirovykh
prostranstv reaktivuymi priboram, (The Probing of
Space by Reaction Devices), Nauchnoe Obozrenie (St.
Petersburg), no. 5, 1903; and Vne Zemli (Beyond the
Earth), Kaluga, 1920 — also available as Beyond the
Planet Earth, transl. by Kenneth Syers. Pergamon Press,
Inc., New York, 1960.
10. Levy, Richard H.: Radiation Shielding of Space
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Avco-Everett Research Laboratory, Everett, Mass.,
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11. Levy, R. H. and French, F. N.: The Plasma Radiation
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12. Bernal, J. D.: The World, the Flesh, and the Devil,
Methuen & Co., Ltd., London, 1929.
13. Carreiro, J., and Mensch, S., Editors: Building Blocks:
Design Potentials and Constraints, Center for Urban
Development Research, Cornell University, N.Y., 1971.
14. U. S. Bureau of the Census: Statistical Abstract of the
United States: 1974 (95th ed.), Washington, D.C., 1974.
15. Henson, H. K., and Henson, C. M.: Closed Ecosystems
of High Agricultural Yield, Princeton University
Conference Meeting, no. 127, on Space Manufacturing
Facilities, Princeton, N.J., May 1975.
16. Shelef, G., Oswald, W.J., and Golueke, C. G.: Study of
Combined Photosynthetic Waste Reclamation Reactor
for Closed Life Support, SERL-University of California,
Berkeley, Calif., 1968. Final Report to AFSC.
17. La Petra, J. W., and Wilson, R. E., Editors: Moonlab.
A Study by the Stanford/Ames Summer Faculty
Workshop in Engineering Systems Design, June
Chapter 4 — Choosing Among Alternatives