"David Findlay" wrote in message
. au...
Is there a way to quantify the amount of noise created by an engine such
as
an SSME? In a vehicle for use for manned long range exploration, would it
be possible to dampen the sound enough to allow engineers to work on a
live
engine(well maybe the feed systems, control gear etc)?

If I remember right, the SSME's generate about 140db and the aft section of
the Shuttle is rated for ~170. I don't know how much of that is engine
machinery and how much is caused by the exhaust.

If you could hypothetically block off all sound created aft of the engine
core, what would it sound like? How loud would it be? I don't know the
answers to those questions... In any case, I don't think working on a live
running engine would be such a good idea. If something as complicated as an
engine was that badly broken that it would need human repairs, it wouldn't
be running anyway.