NASA-STD-3001 Technical Brief

Relevant Technical 

Requirements

Acoustics

OCHMO-TB-035

Rev C

NASA-STD-3001 Volume 2, Rev D

[V2 6073] Launch, Entry, and Abort Noise 

Exposure Limits

[V2 6074] Ceiling Limit for Launch and Entry

[V2 6075] Ceiling Limit for Launch Abort

[V2 6076] Launch, Entry, and Abort Impulse 

Noise Limits

[V2 6077] Hazardous Noise Limits for All 

Phases Except Launch, Entry, and 

Abort

[V2 6078] Continuous Noise Limits

[V2 6079] Crew Sleep Continuous Noise 

Limits

[V2 6080] Intermittent Noise Limits

[V2 6081] Alarm Maximum Sound Level Limit

[V2 6082] Annoyance Noise Limits for Crew 

Sleep

[V2 6083] Impulse Noise Limit

[V2 6084] Narrow-Band Noise Limits

[V2 6085] Infrasonic Sound Pressure Limits

[V2 6087] Acoustic Monitoring

[V2 6088] Individual Noise Exposure 

Monitoring

[V2 6106] Noise Limit for Personal Audio 

Devices

[V2 6115] 24-Hour Noise Exposure Limits

Executive Summary

The NASA-STD-3001 Volume 2 acoustic 

standards ensure an acceptable acoustic 

environment to preclude noise-related hearing 

loss, preclude interference with 

communications, and support human 

performance. The standards are organized by 

mission phase due to the unique differences in 

noise levels and purposes of the standards. The 

launch, entry, and landing phases generate a 

great amount of noise caused by the combustion 

process in the rocket engines, engine jet-plume 

mixing, unsteady aerodynamic boundary-layer 

pressures, and fluctuating shockwaves. These 

phases also generate significant levels of 

infrasonic and ultrasonic acoustic energy. This 

short-term noise exposure normally does not 

exceed 5 minutes of continuous duration. The 

main focus of controlling noise during this phase 

of flight is on protection of crew hearing and 

preservation of critical communications 

capability. 

During on-orbit, lunar, or extraterrestrial 

planetary operations phases when engines are 

inactive, the focus shifts from protecting crew 

hearing to ensuring adequate communications, 

alarm audibility, crew productivity, and 

habitability. Therefore, the maximum allowable 

sound levels are lower than those required for 

launch and entry.
NASA-STD-3001 Technical Brief

OCHMO-TB-035

Acoustics

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Background

Acoustic levels are measured in decibels – dB

• Frequency and time weighting is applied in the processing stage of sound measurement to make 

statistical descriptions of sound (e.g., peak or average level) and/or to make the measurements better 

correspond to human perception.

• Average Predicted risks of hearing damage are based on the noise source’s level (typically reported in Aweighted decibels [dBA]) and duration of exposure.

• “A-weighting” - dBA - compensates for the fact that the ear is comparatively less sensitive to 

lower and very high frequencies. Weighted between 1000 -5000 hertz (Hz).

• Sound pressure level uses a logarithmic scale to represent the sound pressure of a sound relative to a 

reference pressure. The reference sound pressure is typically the threshold of human hearing: 2 x 10-5

Pascals (Pa).

• Impulse is defined as noises lasting shorter than one second.

• Intermittent limits are defined through durations up to 8 hours. For durations longer than 8 hours, the 

continuous limits take over.

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Rev C 2

Acoustic Limits for On-Orbit Phase

[V2 6083] Impulse Noise Limit: measured at 

the crewmember’s head location; less than 

140 dB peak Sound Pressure Limit. [V2 6077] Hazardous Noise Limits: the Aweighted sound level (excluding impulse 

noise and alarm signals) shall be less than 85 

dBA, regardless of time duration. 

[V2 6080] Intermittent Noise 

Limits: for hardware items 

that operate for 8 hours or 

less. Refer to Table 6.6-4 in 

NASA-STD-3001 Volume 2 for 

dBA levels vs. duration.

[V2 6078] Continuous Noise Limits: in spacecraft work areas, limits to values 

given by the Noise Criterion (NC)-50 curve. 50 dB @ 1.5Khz. Refer to Figure 6.6-

1 and Table 6.6-3 in NASA-STD-3001 Volume 2 for dB vs. frequency bands.
NASA-STD-3001 Technical Brief

OCHMO-TB-035

Acoustics

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Acoustic Limits for Launch. Ascent, and Descent Phases

Background

3

[V2 6074] Ceiling Limit for 

Launch and Entry: limit the 

combined A-weighted sound 

levels (not including impulse 

noise) at the crewmembers’ 

ears to a maximum of 105 

dBA.

[V2 6076] Impulse Noise Limit: measured at 

the crewmember’s head location; less than 

140 dB peak Sound Pressure Limit.

[V2 6075] Ceiling Limit for Launch Abort: limit 

the combined A-weighted sound levels (not 

including impulse noise) at the crewmembers’ 

ears to a maximum of 115 dBA

[V2 6073] Launch, Entry, and Abort 

Noise Exposure Limits: the noise 

exposure level (not including 

impulse noise) at the 

crewmember's ear, calculated over 

any 24-hour period, shall be limited 

such that the noise dose is ≤100 

(equivalent to 8-hour 85 dBA TWA).

TWA = Time-weighted average

Risks:

Noise exposure is generally considered to affect hearing, 

but it can also cause other physiological effects (e.g., 

irritation, headaches, and degradation in sleep and 

relaxation). Noise can also affect performance of specific 

activities (e.g., working and speech communications). 

Even noise that the crew does not perceive as harmful 

may cause deleterious effects, as the crew may become 

desensitized to elevated noise levels or not consider the 

noise to be objectionable (i.e., broad-band, ultrasonic, or 

infrasonic noise). Because of this insensitivity to sound 

pressure level changes, it is important to rely on 

quantitative noise measurements when designing 

hardware and verifying acoustic characteristics of space 

vehicles.

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Rev C

Risk of Hearing Loss and 

Performance Decrements Due to 

Acoustics Issues in Space
NASA-STD-3001 Technical Brief

OCHMO-TB-035

Acoustics

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Reference Data

4

The graph above shows sound limits for various conditions across audible frequencies. Note that limits at 

low frequencies are higher than those at high frequencies, since the human ear is more sensitive to high 

frequencies. The NC-50 curve in particular varies from 70 dB at 63Hz to 45 dB at 8 kHz.

Sound levels in the Spacelab Module, a research module located in the Shuttle’s cargo bay during STS-40, 

were measured to be 68 dBA, on a daily average basis, but rose on some days to be as high as 75.5 dBA 

and up to 84 dBA during ergometer operations (Goodman, 1991b). As a result, serious problems with 

communications, both with the ground and between crewmembers, were experienced. Communications 

capability within the Spacelab had become obscured by the high ambient noise levels of the experiment 

hardware, and the crew had to move into the airlock (away from the experiments they were operating) to 

communicate. Noise levels in the Orbiter Crew Module during STS-40 also were high, reaching daily 

averages as high as 71 to 73 dBA compared to 73.5 to 75.5 dBA in Spacelab. The crew was very irritated 

during operations and sleep periods, and reported headaches due to the high noise levels experienced 

(Goodman, 1991a). This is an example of a mission of short duration (less than 30 days) in which high 

noise levels became a problem because of the resulting poor communications and habitability. 

Source: NASA/SP-2015-624 Acoustics and Noise Control in Space Crew Compartments

10/06/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-035

Acoustics

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Application

5

Monitoring

From International Space Station—A Status 

Report:

“Acoustic monitoring is an important part of 

the noise control process on ISS, providing 

critical data for trend analysis, noise exposure 

analysis, validation of acoustic analysis and 

predictions, and to provide strong evidence 

for ensuring crew health and safety, thus 

allowing Flight Certification. To this purpose, 

sound level meter (SLM) measurements and 

acoustic noise dosimetry are routinely 

performed.”

Design Guidance

Examples of design choices to mitigate noise 

exposure include:

• Low-noise fans

• Isolating vibrating equipment and 

components from crewmembers

• Cushioning loud equipment and 

components*

• Noise-dampening blankets and baffles*

*these materials are soft and porous, so 

special considerations must be taken for 

cleanliness and crew health concerns

Additional Information

• Regular maintenance of equipment and 

components helps reduce noise caused 

by off-nominal performance.

• Hearing protection (earplugs, earmuffs, 

etc.) cannot be used to satisfy the 

requirements, as they pose a risk to 

crew comfort, health, performance, and 

communication.

ISS crewmember performs Sound Level Meter (SLM) 

Operations to measure the acoustic environment in 

the ISS.

An acoustic engineer validates the Multi-Purpose 

Crew Vehicle Command Module Volumetric 

Acoustic Mock-up.

10/06/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-035

Acoustics

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Application

6

Noise Control Design

The noise control plan defines the approach 

to be used, and the efforts needed to 

control noise at the source, path, and 

receiver. A good approach would be to 

identify all continuous noise sources; 

determine the source to receiver paths; 

estimate the combined systems noise; 

determine the contribution of each source 

relative to the total noise; and specify the 

applicable noise criteria.

During the dynamic stages of spaceflight 

(takeoff, landing, and abort), there is little 

that be done to mitigate noise at the source 

without substantial design changes to the 

engine. On the ISS, most noise come from 

fans, which can be primarily mitigated 

through source control.

Space Shuttle Noise Paths

Sound 

Path

Source Control Method

Airborne Inlets and exhausts of air 

ducts, exposed equipment, 

leaks through air 

passageways/gaps

Using mufflers or silencers for broadband noise, 

resonators for narrow band noise, active 

acoustic control systems inside the duct, 

applications of sound-absorbing materials in the 

duct lining, and materials to seal the gaps or 

block the noise.

Structure 

borne

Structural vibrations and the 

resultant energy transfer at 

mountings, connections, and 

from surfaces

Using vibration isolators and active vibration 

control systems, applications of passive or 

active damping materials, and decoupling lines 

to preclude the transfer of vibration.

Enclosure 

radiation

Radiated from, or 

transmitted through, 

structural enclosures, 

panels, shelves, and other 

types of closeout materials.

Material changes, the addition of barrier or 

stiffening materials for transmission, the 

addition of damping or viscoelastic materials for 

radiation, addition of absorbent materials inside 

the enclosure to absorb acoustic energy or use 

of active structural acoustic control.

10/06/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-035

Acoustics

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Application

7

Testing and Verification

Sound power and directivity measurements of 

noise sources need to be performed, and the 

results should be used to determine possible 

quieting approaches. Simple mock-ups or 

prototypes can be employed to determine, 

inexpensively, the effectiveness of mufflers or 

other noise reduction devices. Testing of the 

designs and design approaches should be 

performed as much as possible prior to formal 

verification testing to minimize unforeseen 

results, provide time for remedial actions if 

required, and supply a basis for updating of 

the analysis to reflect test results. It is 

important to operate each equipment item 

individually to determine its noise contribution 

and frequency content relative to the total 

noise levels. This provides information for the 

ranking of the contributing sound sources in 

selected frequency bands and helps establish 

priorities for the work to be done.

Computer tools, such acoustic ray tracing and 

statistical energy analysis can be used in 

evaluating noise environments.

ESA (European Space Agency) astronaut Samantha 

Cristoforetti participates in the Acoustic Diagnostics 

study. The investigation explores whether equipment 

noise levels and the microgravity environment may 

create possible adverse effects on astronaut hearing. 

Statistical energy analysis for a refrigerator

Acoustic ray tracing simulation for a music 

hall

10/06/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-035

Acoustics

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Back-Up

8 10/06/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-035

Acoustics

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Rev B  Rev C

• Updated information to reflect the revisions to language 

throughout both volumes of NASA-STD-3001.

• Updated/added website links due to new NASA website 

launch

Rev A  Rev B

• Added information on Noise Control Plans and Testing and 

Verification.

Original  Rev A

• Updated information to be consistent with NASA-STD-3001 

Volume 1 Rev B and Volume 2 Rev C.

Major Changes Between Revisions

9 10/06/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-035

Acoustics

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

NASA-STD-3001 Volume 2 Revision D

[V2 6073] Launch, Entry, and Abort Noise Exposure Limits During launch, entry, and abort operations, the 

noise exposure level (not including impulse noise) at the crewmember's ear, calculated over any 24-hour 

period, shall be limited such that the noise dose (D) is ≤100. 

[V2 6074] Ceiling Limit for Launch and Entry During launch and entry operations, the system shall limit 

the combined A-weighted sound levels (not including impulse noise) at the crewmembers’ ears to a 

maximum of 105 dBA.

[V2 6075] Ceiling Limit for Launch Abort During launch abort operations, the system shall limit the 

combined A-weighted sound levels (not including impulse noise) at the crewmembers’ ears to a maximum 

of 115 dBA.

[V2 6076] Launch, Entry, and Abort Impulse Noise Limits During launch, entry, and abort operations, 

impulse noise measured at the crewmember’s ear location shall be limited to less than 140 dB peak SPL.

[V2 6077] Hazardous Noise Limits for All Phases Except Launch, Entry, and Abort For off-nominal 

operations, broadcast communications, depressurization valves, and maintenance activities, the Aweighted sound level (excluding impulse noise and alarm signals) shall be less than 85 dBA, regardless of 

time duration; except in the case of depressurization valves, the noise attenuation effectiveness of hearing 

protection or communications headsets may not be used to satisfy this requirement.

[V2 6078] Continuous Noise Limits In spacecraft work areas, where good voice communications and 

habitability are required, SPLs of continuous noise (not including impulse or intermittent noise sources) 

shall be limited to the values given by the Noise Criterion (NC)-50 curve in Figure 6.6-1—NC Curves, and 

Table 6.6-3—Octave Band SPL Limits for Continuous Noise, dB re 20 μPa; hearing protection cannot be 

used to satisfy this requirement. 

[V2 6079] Crew Sleep Continuous Noise Limits For missions greater than 30 days, SPLs of continuous 

noise shall be limited to the values given by the NC-40 curve (see Figure 6.6-1—NC Curves, and Table 6.6-

3—Octave Band SPL Limits for Continuous Noise, dB re 20 μPa) in crew quarters and sleep areas. Hearing 

protection cannot be used to satisfy this requirement. 

[V2 6080] Intermittent Noise Limits For hardware items that operate for eight hours or less (i.e., 

intermittent noise), the maximum noise emissions (not including impulse noise), measured 0.6 m from 

the loudest hardware surface, shall be determined according to Table 6.6-4—Intermittent Noise AWeighted SPL and Corresponding Operational Duration Limits for Any 24-hour Period (measured at 0.6 m 

distance from the source or closest distance to crew head, whichever is less). Hearing protection cannot 

be used to satisfy this requirement. 

[V2 6081] Alarm Maximum Sound Level Limit The maximum alarm signal A-weighted sound level shall be 

less than 95 dBA at the operating position of the intended receiver.

[V2 6082] Annoyance Noise Limits for Crew Sleep With the exception of communications and alarms, the 

system shall limit impulse and intermittent noise levels at the crewmember’s head location to 10 dB 

above background noise levels during crew sleep periods. Hearing protection cannot be used to satisfy 

this requirement.

[V2 6083] Impulse Noise Limit The system shall limit impulse noise measured at the crewmember’s head 

location to less than 140 dB peak SPL during all mission phases except launch and entry. Hearing 

protection cannot be used to satisfy this requirement.

Referenced Technical Requirements

10 10/06/2023

Rev C

View the current versions of NASA-STD3001 Volume 1 & Volume 2 on the 

OCHMO Standards website
NASA-STD-3001 Technical Brief

OCHMO-TB-035

Acoustics

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

NASA-STD-3001 Volume 2 Revision D

[V2 6084] Narrow-Band Noise Limits The maximum SPL of narrow-band noise components and tones 

shall be limited to at least 10 dB less than the broadband SPL of the octave band that contains the 

component or tone.

[V2 6085] Infrasonic Sound Pressure Limits Infrasonic SPLs, including frequencies from 1 to 20 Hz but not 

including impulse noise, shall be limited to less than 150 dB at the crewmember’s head location. Hearing 

protection cannot be used to satisfy this requirement.

[V2 6087] Acoustic Monitoring Broadband and frequency-dependent SPLs shall be monitored and 

quantified as needed for crew health and safety.

[V2 6088] Individual Noise Exposure Monitoring Noise exposure levels shall be monitored and quantified 

for each crewmember as needed for crew health and safety.

[V2 6106] Noise Limit for Personal Audio Devices The system shall limit the maximum A-weighted sound 

level at the crewmember’s ear created by a personal audio device to 115 dBA or less.

[V2 6115] 24-Hour Noise Exposure Limits The noise exposure level (not including impulse noise) at the 

crewmember's ear, calculated over any 24-hour period, except during launch, entry, and abort operations, 

shall be limited such that the noise dose (D) is ≤100.

All referenced tables and figures are available in NASA-STD-3001 Volume 2 Revision D.

Referenced Technical Requirements

11 10/06/2023

Rev C

View the current versions of NASA-STD3001 Volume 1 & Volume 2 on the 

OCHMO Standards website
NASA-STD-3001 Technical Brief

OCHMO-TB-035

Acoustics

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Reference List

12

1. Human Landing System (HLS) Requirements Document HLS-RQMT-001. Internal NASA Document.

2. Allen, C. (1998). International Space Station Acoustics – A Status Report. Inter-Noise and Noise-Con 

Congress and Conference Proceedings, InterNoise 18, pages 994 - 1998, Chicago, IL, pp. 1319-1334(16).

3. Acoustics and Noise Control. (2015). https://www.nasa.gov/content/acoustics-and-noise-controlcapability

4. Goodman, J.R., & Grosveld, F.W. (2015). Acoustics and Noise Control in Space Crew Compartiments. 

NASA/SP-2015-624. https://ntrs.nasa.gov/api/citations/20160000818/downloads/20160000818.pdf

5. Zarate, R., Poblet-Puig, J., Ortega, M., and Lopez-Parra, M. (2020). Statistical Energy Analysis Model for 

Sound Pressure Level Prediction on Refrigerators. Acoustics Australia, 48, 233-250.

6. Christopher, B. (2022). Validating an Acoustic Ray Tracing Simulation of a Chamber Music Hall. COMSOL 

Blog. Retrieved from: https://www.comsol.com/blogs/validating-an-acoustic-ray-tracing-simulation-ofa-chamber-music-hall/

10/06/2023

Rev C