41 votes
Accepted

What sounds do astronauts hear inside their helmets during an EVA?

Tom Jones talks about it some in his memoir "Skywalking" when he describes an EVA carried out on shuttle mission STS-98: Inside the airlock when it is pressurized Through the helmet shell, from ...
Organic Marble's user avatar
36 votes
Accepted

Microphone on Mars

Your premise is incorrect. Microphones have been carried on Mars missions, they just failed to work. Mars 2020 (now Insight) will carry microphones. NASA spacecraft that traveled to Mars in the past ...
Hobbes's user avatar
  • 128k
18 votes
Accepted

How can you make a rocket quieter?

According to https://www.mdpi.com/2076-3417/12/10/4874, jet noise in aircraft is due to shear “turbulence pulsation formed by the rapid mixing of the high-speed air jet from the nozzle and the ...
Woody's user avatar
  • 21.6k
17 votes

Till what altitude above earth sounds can be heard?

tl;dr: There's certainly some propagation of sound waves possible at 100 km altitude. With a density a million times lower than at the surface the mean free path of individual molecules will approach ...
uhoh's user avatar
  • 149k
17 votes

Has sound ever been used to diagnose a problem not shown by other measurements?

The shuttle Orbiter's wing leading edges, constructed of reinforced carbon-carbon (RCC) composite material, were tested in part by technicians tapping on them and listening to the resulting sounds. It ...
Organic Marble's user avatar
15 votes
Accepted

Till what altitude above earth sounds can be heard?

The title of the question asks Till what altitude above earth sounds can be heard? @uhoh gave a detailed answer to that question. I'll instead speculatively answer an implied question in the body of ...
David Hammen's user avatar
  • 74.8k
14 votes

Can astronauts hear sounds during space walks for repairs?

According to WIRED Magazine's article and video Watch Astronauts Answer Your Burning Questions about Space (also viewable on YouTube): Sounds exist in space, but humans can not hear them. As pointed ...
uhoh's user avatar
  • 149k
13 votes

Can astronauts hear sounds during space walks for repairs?

Many years ago, as a young engineer, I worked for Hamilton Standard who developed the Space Suit, and which had the remit to develop a Power Tool for Astronauts for the purposes of repairing the Space ...
m douglas bibbey's user avatar
12 votes

What would sounds on Mars be like?

This is a fantastic question! There are some sounds recorded by a GoPro camera high in Earth's atmosphere in the video linked in the question How did the tangential thrusters for the 2014 LDSD test ...
uhoh's user avatar
  • 149k
12 votes

Has sound ever been used to diagnose a problem not shown by other measurements?

I'm not sure how widely you are casting the breadth of your question. But I know jet engine mechanics always listen to a turbine as it runs up, reaches steady state, then is powered down. I knew the ...
Chris Ison's user avatar
11 votes

Which was louder, SRBs or SSMEs?

Submitted as a somewhat subjective answer - you never know what sound editors did. These are two clips from the early shuttle IMAX file The Dream is Alive. This agrees fairly well with my experience ...
Organic Marble's user avatar
10 votes
Accepted

Can astronauts inside ISS hear their crewmates doing EVAs?

Yes, you can hear the noise of anything that hits the outside of the ISS, because from that point there is no vacuum - vibration is passed to the inside of the ISS where it is audible. This is all ...
Rory Alsop's user avatar
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9 votes
Accepted

What sounds did the Apollo astronauts hear during launch

There's a lot of variations in the astronauts' subjective impressions of the sound: "muffled roar", "gutteral roar", and allusions to infrasonic vibration, for which "rumble&...
Russell Borogove's user avatar
9 votes

Has sound ever been used to diagnose a problem not shown by other measurements?

If you count ultrasound inside metal as sound: From this answer to Why do they believe that the Bigelow Expandable Activity Module has “taken a hit”?: After some research and this article I found out ...
uhoh's user avatar
  • 149k
8 votes
Accepted

Why don't we use sound suppression system when rocket lands propulsively?

The amount of energy involved in a take off and landing will be roughly equal to the mass being moved, and approximately the same proportion of energy will be turned into sound given the same engines ...
GremlinWranger's user avatar
8 votes
Accepted

Why doesn't this SpaceX rocket test fire use water sprays?

The amount of white vapor present at the beginning and end of the test suggests that there is indeed a water spray down within the flame trench. There is no need for above-grade spray because the ...
Tristan's user avatar
  • 17.3k
8 votes

Has sound ever been used to diagnose a problem not shown by other measurements?

If you count ultrasound Several leaks aboard the ISS were first discovered by an increase in the rate of depressurization of the station that could not be accounted for by known causes. These can be ...
uhoh's user avatar
  • 149k
8 votes

Has sound ever been used to diagnose a problem not shown by other measurements?

If you count seismic vibrations as sound From this answer to How are the most sensitive seismometers on Mars protected from the most powerful jackhammer on Mars just a few feet away?: The SEIS team ...
uhoh's user avatar
  • 149k
7 votes
Accepted

Is the Falcon Heavy as loud as the Space Shuttle or Saturn V?

Expected noise levels can be found in the environmental assessment. For Falcon 9: 156.1 ± 4.9 dB (unweighted) at 125 ft. For Falcon Heavy: 160.9 ± 4.9 dB (unweighted) at 125 ft. So asdfex's ...
Hobbes's user avatar
  • 128k
7 votes

Stethoscope as a backup communication device

A real stethoscope has some features that make it useful in normal use, but would be a hindrance in your scenario. The sound conductance medium is the air column in the tube, not the tube itself. ...
BowlOfRed's user avatar
  • 6,882
7 votes

Did Voyager 1 and 2 record while not near any planets to get "ambient mechanical noise" for smoothing?

I think you might have some misconceptions about what that spectrogram represents, and how it might have been processed. The purpose of recording audio "room tone" is not to remove background noise, ...
Jim Lewis's user avatar
  • 931
6 votes
Accepted

Why did the Apollo cabin repressurization valve cause a banging sound?

Odds are it was the spring slamming the valve closed. Green arrows are the flow path. Red arrow shows the spring. Diagram from Apollo Spacecraft News Reference page 122
Organic Marble's user avatar
6 votes
Accepted

Does a rocket sound louder to the astronauts as it leaves the atmosphere?

However, once in space, the vacuum does not transmit sound, so any sound produced by the engines will be contained to the spacecraft. No. The sound produced by the engines is mostly in shockwaves ...
Hobbes's user avatar
  • 128k
6 votes
Accepted

What is that thing spraying during a Falcon 9 launch?

It is a sound suppression system like the one developed by NASA for the Space Shuttle in the 1980s. It was required to keep the sound level below the required 145 dB. See: https://www.nasa.gov/...
Dan Sorensen's user avatar
  • 3,551
6 votes
Accepted

Where does the noise on spacewalks come from?

Short answer: These "sounds" consist of vibrations produced by the astronaut's movements and his suit systems and transferred through his space suit, camera enclosure and PCB the microphone is ...
ZuOverture's user avatar
6 votes

Which was louder, SRBs or SSMEs?

(not an answer yet, I have yet to find SPL data for the SRBs) Thanks to the discussion and videos it does seem that the SRBs are louder. However, I had a vague notion that turbulence was important, ...
0xDBFB7's user avatar
  • 2,239
6 votes
Accepted

Why didn't the EDL mic record sound during the entry and descent of Perseverance?

There's an interview with the audio engineer for the mission, Jason Achilles Mezilis, on the Naked Scientists Podcast. The system was supposed to record five and a half minutes of audio during the ...
BowlOfRed's user avatar
  • 6,882
5 votes

Does gravity affect sound on different mass planets?

Yes and no. It's a yes in that gravity is often responsible for the density of the atmosphere, at least on a planet or gas cloud. Higher air density often means a higher speed of sound for the same ...
GdD's user avatar
  • 20.3k
5 votes

Have astronauts ever used the helmet-to-helmet technique to talk to one another in vacuum?

In space, (probably) no-one can hear you scream through glass (very well) This is an interesting "Have astronauts ever...?" question, and I can't answer it directly. I can't answer if it's ...
uhoh's user avatar
  • 149k
4 votes

Why don't we use sound suppression system when rocket lands propulsively?

As other answers have pointed out, the necessary noise is much lower for landing than take off, but this doesn't mean that the actual amount of noise will be so reduced. As control theory gets better, ...
ANone's user avatar
  • 3,432

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