General Question Valve Sound - What is that?

[Luft2010]

When playing DG with sound I occasionally hear some kind of pump working and valve opening and closing. I wonder what's the space ship is supposed to be doing at that time, or what the sound represents?

Thanks

 

[N_Molson]

Those are the default ambiance random sounds played by OrbiterSound. There's no link with the DG itself, you'll hear the same with any vessels (except those which have defined ambiance sounds).

 

[Luft2010]

Ah ok I thought it is supposed to represent some process.

 

[Urwumpe]

Ah ok I thought it is supposed to represent some process.

It is just for having some better generic sounds, since spacecraft are usually VERY loud inside. you would suffocate from your own breath in minutes if no fan would blow the fresh air to you in micro-gravity. Relay activity and valves are always around you there as well.

 

[_Designer_]

It is just for having some better generic sounds, since spacecraft are usually VERY loud inside. you would suffocate from your own breath in minutes if no fan would blow the fresh air to you in micro-gravity. Relay activity and valves are always around you there as well.

I learn something new everyday

 

[N_Molson]

As far as I know, there is a good 40-60 dB whistle continuous sound in most past or existing spacecraft, caused by the use of 400 Hz electrical current (the "A" note of a tuner is 440 Hz). And as said Urumpwe, you have the fans, and also the cooling systems ammonia pumps....

I read somewhere that the background continous noise inside the Mir station, when all systems were online, was peaking at 80dB. In comparison, you get the same level of noise when you stand on the side of a saturated highway. And from what I read (notably J. Linenger's book), sleeping was not easy for that reason amongst others.

 

[Urwumpe]

and then you have thruster sounds - and believe me - the default Orbiter thruster sounds are far too silent. A Shuttle nose thruster sounds more like Thor banging his hammer against the cabin walls.

 

[_Designer_]

how many times have you been in space?

 

[Urwumpe]

how many times have you been in space?

Twice.

 

[garyw]

Urwumpe is correct. The OMS & RCS sound like canon fire and thats a quote from Bob Cabana who has been in space quite a bit.

 

[Notebook]

Also, if you are very old(and daft enough) you may well believe that thermionic devices have a better sound than solid state devices...

[ame="http://en.wikipedia.org/wiki/Valve_audio_amplifier"]Valve audio amplifier - Wikipedia, the free encyclopedia[/ame]

N.

 

[N_Molson]

That's one of the big paradoxes of spaces : sounds can't travel into the void, so if you put a (radiation shielded) microphone on a , you get nothing.

However, all humans that get there experience a high level of noise : even in EVA suits, there are multiple fans (and small fans are very noisy) ; the breath sound, pressure valves, radio comms, suit warning/information signals...

So, for an human being, space is in fact a very noisy place

 

[T.Neo]

and then you have thruster sounds - and believe me - the default Orbiter thruster sounds are far too silent. A Shuttle nose thruster sounds more like Thor banging his hammer against the cabin walls.

What about the aft thrusters? And the thrusters of other spacecraft?

Why are there no thruster noises in Apollo recordings? Am I not paying enough attention to hear them?

 

[MaverickSawyer]

perhaps the sound didn't conduct very well through the umbilical connections and the holddown cables for the CM...

 

[Urwumpe]

What about the aft thrusters? And the thrusters of other spacecraft?

Why are there no thruster noises in Apollo recordings? Am I not paying enough attention to hear them?

The aft thrusters are only almost as loud - but still pretty loud. Since there is no air to transfer the sound, you only have the structure left to conduct it.

During the Space Shuttle reentry videos, you have to remember that the forward RCS is disabled at this point. Every thruster firing is aft.

For Apollo, I would suggest ignorance and the fact that the few thruster firings you could have heard are only during phases when an astronaut is speaking at the same time.

 

[N_Molson]

Also, microphones used during Apollos missions are not of excellent quality, and the recording conditions were random. That was not a point of focus, even video was more important. The quality had to be sufficient to make intelligible an astronaut talking, which means a bandwith of roughly 150-1500 Hz.

Thrusters sound are mostly low frequency sounds produced by vibrations on the spacecraft hull, and the microphones could probably hardly record that. Try to record a rock'n'roll live with a portable microphone, you'll hardly hear the bass player. When on site, close enough from the amps, you feel each note passing through your skeleton.

 

[Scav]

When on site, close enough from the amps, you feel each note passing through your skeleton.

:headbang:

The IMAX films, in my opinion, do a decent job of portraying the aural environment inside the shuttle. You hear fans, pyro charges launching communications satellites, and the astronauts' voices echoing off the walls (and ceilings).

(The Dream Is Alive cited here.)

 

[Luft2010]

It's very nice to know many of these new facts about sound in spaceship. I'll be sure to imagine them whilst playing Orbiter.

 

[n72.75]

Why are there no thruster noises in Apollo recordings? Am I not paying enough attention to hear them?

Remember, the Apollo Service Module RCS thrusters are smaller than the Shuttle's also, consider how vibrations are transferred between the CM and SM.

 

[T.Neo]

Not sure how relevant this is, but some footage of Buran RCS and OMS ground testing:

[ame="http://www.youtube.com/watch?v=1L7sIG-2BHg"]Buran OMS Engine & Thruster Testing [/ame]