aoab314@ut-emx.UUCP (Srinivas Bettadpur) (07/24/90)
Howdy folks,
I was reading this rather interesting article in the third world
business magazine SOUTH (issue of June 1990, pg 105). This article
reports a study by two Soviet scientists V. Burdakov and V. Filin
on the effects of space shuttle flights on the depletion of the ozone
layer. Some salient numbers from that article are :
U.S. Space Shuttle :
Solid propellant fuels; Before reaching an altitude of 50
km, one flight emits 187 tonnes of Chlorine
7 tonnes of Nitrogen
177 tonnes of Aluminium Oxide aerosols
estimated destruction of 10 million tonnes of ozone, requiring
a total of 300 flights to completely destroy the ozone layer.
The Delta rocket destroys about 8 million tonnnes of ozone and other
culprits include the Titan II, Ariane V and other rockets using solid
propellants.
Incidentally, the Energiya, with its mix of oxygen and hydocarbon
fuel for first stage and a mix of hydrogen-oxygen for second stage,
destroys only 1500 tonnes of ozone.
Knowing squat about either the shuttle or the chemistry of its
propulsion, I thought this might be a good place to start to cast
about for further information.
S. Bettadpur
Bitnet : aoab314 @ utchpc
Other : aoab314@frio.chpc.utexas.edu
aoab314@emx.cc.utexas.eduheksterb@apple.com (Ben Hekster) (07/25/90)
Yeah, and we all know how much good the Russians are doing the atmosphere by launching those hundreds upon hundreds of spy satellites which they can't keep in orbit for more than a couple of weeks. Nice to know that they have such an interest in our space program, though.
schraudo@beowulf.ucsd.edu (Nici Schraudolph) (07/26/90)
heksterb@apple.com (Ben Hekster) writes: >Yeah, and we all know how much good the Russians are doing the atmosphere >by launching those hundreds upon hundreds of spy satellites which they >can't keep in orbit for more than a couple of weeks. Nice to know that >they have such an interest in our space program, though. Are these satellites launched with solid fuels, or with hydrogen/oxygen? Please don't post such knee-jerk responses without supplying facts to back them up. Mr. Bettadpur has been so kind to share some interesting (and if true, quite frightening) facts with us, and I am hoping to see an intelligent follow-up discussion on the truth behind these figures. In particular, I'd appreciate comments on the following aspects: 1) Are the tonnages of released chemicals correct? Is the classification fine enough to assess ozone damage from it, or do we need to treat a host of combustion products each individually? 2) Is the tonnage of destroyed ozone correct? Moreover, does it make sense at all to make such a direct implication, discounting a host of phenomena (eg. spatial and temporal distribution of combustion products & ozone)? 3) Does the "300 shuttle trips = 1 ozone layer" equation take into account that the ozone layer is a dynamical system, with ozone continually being created and destroyed? The statement "300 shuttles starting simultaneously and dispersing their exhausts evenly and instantaneously = 1 ozone layer" is far less scary, especially at the rate at which NASA is launching shuttles these days... :-( On the other hand, dynamical systems can also amplify small perturbations - how much is known about the stability of the ozone layer as a dynamical system? From the articles I've read it seems rather well-behaved, unlike the runaway greenhouse effect. 4) Finally, politics: are there Environmental Impact Reports on NASA activities such as rocket launches, or has NASA a special exempt status? Does anybody in this group have access to an EIR on shuttle launches? Care to post a summary? -- Nici Schraudolph, C-014 nschraudolph@ucsd.edu University of California, San Diego nschraudolph@ucsd.bitnet La Jolla, CA 92093 ...!ucsd!nschraudolph
pat@grebyn.com (Pat Bahn) (07/27/90)
Um I remember seeing some nasa studies on shuttle effects on the Ozone layer, from the late 70's. They were concerned about it, but then they realized the shuttle would fly so little as to have negligible effect. Look around the AW&ST archives and you'll find it. the principal problem is the SRB use an ammonium perchlorate in the fuel and that released at upper atmosphere, causes problems... I believe the sovs use H202 and Lox/kerosene. henr would know better...[ -- ============================================================================= Pat @ grebyn.com | If the human mind was simple enough to understand, 301-948-8142 | We'd be too simple to understand it. -Emerson Pugh =============================================================================