From: henry@spsystems.net (Henry Spencer)
Newsgroups: sci.space.tech
Subject: Re: Rockets damaging Ozone?
Date: Thu, 1 Apr 1999 03:29:25 GMT

In article <7dme42$cga$1@vixen.cso.uiuc.edu>,
blair patrick bromley <bromley@students.uiuc.edu> wrote:
>   Fortunately, the most desirable propellant combinations (H2/O2, CH4/O2,
>kerosene/O2, and other hydrocarbon/oxygen fuel combinations) should not
>have any deleterious effect on the ozone levels.  Solid rockets and
>storable propellants (except hydrocarbon/H2O2) are the culprits.

Uh, not really.  If memory serves, hydrogen actually is an ozone
antagonist.  And so are nitrogen oxides, which are formed by *any* hot
exhaust hitting air.  (For that matter, they are also formed in reentry;
a shuttle reentry produces quite substantial amounts of nitrogen oxides.)

And as I recall, there's nothing particularly problematic about the
exhaust from storable propellants.  (The propellants themselves are
another matter, but they are not very stable in exhaust conditions.)

Even the exhaust from solids, although messy, is not as problematic as
some of the more hysterical might think.  Although it typically does have
a lot of chlorine in it, it's almost all as HCl, which is very soluble in
water and is never going to make it up into the ozone layer (and is made
in much greater volume by volcanos and by industrial processes anyway).
Only solids that burn long enough to reach quite high altitudes present
much in the way of ozone problems, by injecting chlorine compounds
directly into the vulnerable regions.  The small strap-ons often used
for extra thrust at takeoff, in particular, are unlikely to be a problem.

>   It just so happens that the Russian's popular Proton uses NO4/UDMH
>storable propellants which have somewhat toxic combustion products.

See above on toxicity of the exhaust.  And the much more heavily used
Soyuz booster is LOX/kerosene, as is Zenit.
--
The good old days                   |  Henry Spencer   henry@spsystems.net
weren't.                            |      (aka henry@zoo.toronto.edu)