Spacecraft Sound Levels

What was the sound environment like inside the various space vehicles? For
later ships like the Shuttle, I imagine it sounds a lot like my office- just
a bunch of fans. The Mercury's, would seem to me to be the quietest, just
because of their simplicity, if nothing else.

I recall reading somewhere that the Apollo astronauts who tried to sleep on
the moon complained that the LEM made an assortment of unusual sounds, some
not very reassuring.

Thanks...

On Mon, 22 Aug 2005 14:30:14 -0500, Ken Webster wrote
(in article ):

What was the sound environment like inside the various space vehicles? For
later ships like the Shuttle, I imagine it sounds a lot like my office- just
a bunch of fans. The Mercury's, would seem to me to be the quietest, just
because of their simplicity, if nothing else.

I recall reading somewhere that the Apollo astronauts who tried to sleep on
the moon complained that the LEM made an assortment of unusual sounds, some
not very reassuring.

Thanks...



For the U.S. pressurized elements of SSF/ISS, individual subassemblies
were spec'd for an overall cabin noise level of NC40 - essentially
time-weighted average sound pressure levels of 40 dB. For most
components and subassemblies this was not a problem. However, for the
CDRA with it's absurdly-high RPM fan this was a tremendously-difficult
spec for the vendor to reach and I don't believe they ever made it.
Eventually it was proposed to raise the spec for cabin noise (right
about the time I left) and I don't know what happened after I left.

--
"Fame may be fleeting but obscurity is forever." ~Anonymous
"I believe as little as possible and know as much as I can."
~Todd Stuart Phillips
www.angryherb.net

Herb Schaltegger wrote:

For the U.S. pressurized elements of SSF/ISS, individual subassemblies
were spec'd for an overall cabin noise level of NC40 - essentially
time-weighted average sound pressure levels of 40 dB. For most
components and subassemblies this was not a problem. However, for the
CDRA with it's absurdly-high RPM fan this was a tremendously-difficult
spec for the vendor to reach and I don't believe they ever made it.
Eventually it was proposed to raise the spec for cabin noise (right
about the time I left) and I don't know what happened after I left.



IIRC, didn't we have to replace the Russian fans because of their noise
levels?

Pat

I think there was a mention in Gene Cernan's "Last Man on the Moon"
that he and Jack spent a bit of time calling out to each other guesses
on what was making which noise during their rest period.

Knowing that there was a chewing-gum-wrapper thickness of metal
separating the cabin air from the lunar atmosphere would have kept me
jumping at every pop and ping.

"In the first octave, SPL= 145 db re 0.0002 /_bar. If the cabin
pressure is assumed to be 10 psi, then SPL = 143 db re 0.0002 8bar."

Project Orion Conceptual Vehicle Designs Volume III pg 104 of the pdf

Herb Schaltegger wrote:

For the U.S. pressurized elements of SSF/ISS, individual subassemblies
were spec'd for an overall cabin noise level of NC40 - essentially
time-weighted average sound pressure levels of 40 dB. For most
components and subassemblies this was not a problem. However, for the
CDRA with it's absurdly-high RPM fan this was a tremendously-difficult
spec for the vendor to reach and I don't believe they ever made it.

what was the design rationale to use this paricular fan .. ? what
prevents going to a larger ans slowel (=quiet) fan?

servus

markus

On Tue, 23 Aug 2005 12:33:42 -0500, Markus Baur wrote
(in article ):

Herb Schaltegger wrote:

For the U.S. pressurized elements of SSF/ISS, individual subassemblies
were spec'd for an overall cabin noise level of NC40 - essentially
time-weighted average sound pressure levels of 40 dB. For most
components and subassemblies this was not a problem. However, for the
CDRA with it's absurdly-high RPM fan this was a tremendously-difficult
spec for the vendor to reach and I don't believe they ever made it.

what was the design rationale to use this paricular fan .. ? what
prevents going to a larger ans slowel (=quiet) fan?

servus

markus


Volume allowable for the fan assembly and the required flow rates
through the CDRA, primarily. Packaging the ECLSS equipment was/is a
tremendously difficult problem.

--
"Fame may be fleeting but obscurity is forever." ~Anonymous
"I believe as little as possible and know as much as I can."
~Todd Stuart Phillips
www.angryherb.net

"Ken Webster" wrote in message
...
What was the sound environment like inside the various space vehicles? For
later ships like the Shuttle, I imagine it sounds a lot like my office-
just a bunch of fans. The Mercury's, would seem to me to be the quietest,
just because of their simplicity, if nothing else.

Didn't the Mercury instrument panel include a mechanical clock? I think
it was electrical, not wind-up, but it still made a "tick-tock" sound from
the escapement mechanism IIRC.

On Wed, 24 Aug 2005 23:01:29 GMT, "Rocky Top"
wrote:

Didn't the Mercury instrument panel include a mechanical clock? I think
it was electrical, not wind-up, but it still made a "tick-tock" sound from
the escapement mechanism IIRC.

....This begs a gag rendering for Orbiter, with the Mercury console
having a big wind-up key next to the clock :-)

OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

wrote:
Does anybody know of any other cases in which engines either were or
were not audible in the cockpit?


I've heard RCS thruster firings on the shuttle compared to howitzers...
and (IIRC) the STS-1 mission report states that the crew mainly used the
verniers for attitude control so they wouldn't be woken up/disturbed by
the larger thrusters firing