NASA-STD-3001 Technical Brief

Relevant Technical 

Requirements

Acceleration

OCHMO-TB-024

Rev C

NASA-STD-3001 Volume 2, Rev D

[V2 6064] Sustained Translational 

Acceleration Limits

[V2 6065] Rotational Velocity

[V2 6066] Sustained Rotational Acceleration 

Due to Cross-Coupled Rotation

[V2 6067] Transient Rotational Acceleration

[V2 6069] Acceleration Injury Prevention

[V2 6070] Injury Risk Criterion

[V2 6111] Dynamic Mission Phases 

Monitoring and Analysis

[V2 6112] Hang Time Limit

[V2 6113] Crew Limits in Launch Orientation

Executive Summary

Acceleration limits are set in the x, y, 

and z axes for all mission phases to 

protect the crew from injury and other 

acceleration-related conditions. These 

limits are divided into two-time 

regimes: 

• sustained (>0.5 seconds), and 

• transient (≤0.5 seconds)

They are further divided according to:

• whether the acceleration is 

translational or rotational

• the phase of flight, and 

• whether the crew is standing or 

sitting

Several countermeasures can be used to 

mitigate the effects of high acceleration 

loads. Additional factors such as 

parachute sway and seat angle need to 

be considered when assessing risk and 

developing solutions.

SpaceX Crew Dragon Launch

From: https://www.youtube.com/watch?v=xY96v0OIcK4
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

Basis of Current Limits

• Sustained: prior crewed vehicle data; human tolerance limits

• Transient: Apollo lunar landing impact data; Shuttle & International 

Space Station (ISS) post-flight crew jump data; ISS inflight treadmill foot 

strike data

The Brinkley Dynamic Response Model

Dynamic Response (DR)

• Estimates the transient acceleration of the human body

• A single degree of freedom lumped mass model

• Calculated independently in each direction

• Responses are highly specific for seat used in development

• Changes to the seat, restraints and helmet can invalidate the 

model natural frequency and damping coefficient

• Ground rules established to ensure model is valid to use

Injury Risk Criterion (β)

• Preset DR limits in each direction estimate the injury risk

• Estimates an injury risk but not severity or anatomical location

Limitations

• Subject pool limited to mostly young, male military volunteers

• DR Limits based on limited statistical analysis of injury data 

• Limited validity in +X, -Z and ±Y axes

Note: Information applicable to all axes

10/04/2023

Rev C 2

The 50% probability (P) of injury for +z axis is based on an n greater than 100, yielding 95% confidence 

interval (P=0.5, n=100) is 0.402 ≤ P ≤ 0.598. Where P=0.11 and n=89, the 95% confidence interval is 

0.045 ≤ P ≤ 0.175. The confidence intervals for the +z axis means become smaller for lower risk values 

(5% and lower).

From: NASA/TM-2013-217380

For information on how to use this model, see NASA/TM-2013-

217380, Revision 1, Application of the Brinkley Dynamic Response 

Criterion (BDRC) to Spacecraft Transient Dynamic Events.

From: 

https://ascelibrary.org/doi/10.1061/%

28ASCE%290893-

1321%282009%2922%3A3%28214%2

9

Category Approximate Risk

Low 0.5%

Medium 5.0%

High 50%

Approximate Risk Associated with Each Brinkley Dynamic 

Response Criterion Category
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

Health and Performance Risks of Excessive 

Acceleration Exposure

Sustained

• Limited/difficulty of movement & breathing; 

unconsciousness

• See Requirement [V2 6064] in NASA-STD-3001 Volume 2 for 

limits

• Reference Human Integration Design Handbook (HIDH) Table 

6.5-3

Transient

• Mostly traumatic injuries 

• Vertebral injuries most common

• See Requirements [V2 6069] & [V2 6070] in NASA-STD-3001 

Volume 2, Rev C for limits

• Reference HIDH Section 6.5.3.2

Rotational

• Disorientation; sickness; unconsciousness

• See Requirements [V2 6065-67] in NASA-STD-3001 Volume 2 

for limits

3

For acceleration requirements for extraterrestrial surface 

transport vehicles, reference OCHMO-TB-023, 

Extraterrestrial Surface Transport Vehicles (Rovers).

From: https://www.military.com/video/aircraft/jetfighters/passing-out-at-8gs/4552888570001

From: 

http://www.eurailsafe.net/subsites/operas

/HTML/Section3/Page3.3.2.htm

From: https://www.bcmlawyers.com/how-whiplash-cancause-lasting-trauma-and-pain/

From: https://www.researchgate.net/figure/Average-roll-pitch-andyaw-angles_fig2_262055313

10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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.

Sustained Acceleration

Special sustained acceleration limits for the body-Z axis while standing 

were defined for Artemis mission based on data from Apollo and the 

Cardiovascular and Vision Laboratory’s database. These limits provide 

insight into what would be appropriate for lunar and Martian missions. 

See NASA/TM-20205008196 Artemis Sustained Translational 

Acceleration Limits: Human Tolerance Evidence from Apollo to 

International Space Station for more information. Using a lower body 

compression garments allows for higher magnitudes in the +Az 

direction.

Transient Acceleration

The injury risks given in [V2 6069] Acceleration Injury Prevention are 

based on the expected rate of injuries using data from 80 flights of 4 

crewmembers (320 total exposures) in the Orion vehicle. These were 

then separated into two categories of probability of the dynamic vehicle 

event occurring (with 95% representing most nominal cases and 5% 

some more intense, but still nominal and off-nominal cases). The Class I 

and II values came from the asymptotes of a binomial distribution to 

500 cases where 95% and 5% of landing cases contained 75% and 25% 

of the total injury risk, respectively. The Class III and IV values were 

based off of the NASA loss of crew standard of 0.1%. The second Class 

III value for the 5% category was based on a pad abort land landing.

Reference Data

4

NASA Gradient Compression 

Garment

From: 

https://ntrs.nasa.gov/api/citati

ons/20170000798/downloads/

20170000798.pdf

Injury Severity (Class)* >95% of dynamic cases <5% of dynamic cases

Minor (I) <4% <23%

Moderate (II) <1% <4%

Severe (III) <0.1% <0.7%

[<1%]

Life-Threatening/Fatal (IV) <0.1% <0.7%

Table 6.5-9—Acceptable Injury Risk Due to Dynamic Loads, from: [V2 6069] Acceptable Injury Risk 

Table, NASA-STD-3001 Volume 2, Rev D

The Brinkley Dynamic Response model gives estimations of risk chance for transient accelerations 

in the three standard body axes based off of data from a wide range of aerospace and nonaerospace sources. NASA/TM-2013-217380REV1 gives an explanation of the equations and 

variables used to calculate the risk value.

10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

Design Guidance

• Assumptions of the standing limits given in the requirements:

• Additional equipment (suit) mass borne by the crewmember is <20% of the 

crewmember’s shirtsleeve mass

• Adequate restraint(s) are provided for all body postures

• Cross-discipline considerations

• Critical to consider suit design and mass

• Hard points on suit can cause injury during transient loads (landing)

• Space between a crewmember and their suit, as well as the suit and the vehicle 

habitat, may cause physical harm

• Vibration & acceleration during dynamic phases of flight 

• If a crewmember is already experiencing high G loads (and subsequently limited 

movement), the effects of vibration on performance may be increased

• Potential countermeasures to orthostatic intolerance while standing

• Physical/Vehicle (e.g., suit weight or bodyweight offloading, restraint systems)

• Suit (e.g., anti-g suit, lower body compression)

• Physiological (e.g., scheduled muscle contractions; breathing exercises; fluid 

loading and salt tablets)

• All countermeasures should work concurrently to reduce risk and harm to the 

crew

5 10/04/2023

Rev C

• Considerations to meet transient and sustained 

loads requirements 

• Restraint systems during transition from 

microgravity

• Offloading of suit mass that still enables 

crew performance

• The suit, vehicle, and restraint systems must 

all interact conjointly to protect the crew 

from all types of acceleration loads

• Seat design along with load attenuation is a 

critical design element that mitigates loads 

imparted to the crewmember.

• Mission elapsed time: total time from launch until 

the acceleration load occurs.

Risk of Injury from Dynamic Loads
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

Seat Angle

For impact tolerance, the +Gx orientation is the 

most advantageous direction of loading. In this 

orientation, humans can withstand much higher 

accelerations (by a factor of >2) than in other 

vectors. However, unless a vehicle lands with a 

zero downrange velocity, the landing impact will 

not be purely confined to a single axis. The +Gz

orientation is most advantageous as the 

secondary impact vector due to increased 

tolerance and greater model fidelity in predicting 

injury. 

In a vehicle with no roll control, any direction 

of impact is equally likely. In each vehicle case, 

an extensive assessment of nominal, off-nominal 

and contingency conditions would be necessary 

to accurately assess the risk to the crew due to 

impact. Depending on the direction of impact, 

different seat angles could either increase or 

decrease the risk of injury. A combination of roll 

control and a seat configuration that ensures a 

+Gx and +Gz impact is preferred.

6

From: 

https://www.researchgate.net/figure/Restraintconfiguration-Torso-restraints-are-shown-in-blackpelvis-restraints-are-shown_fig10_260310327

From: https://www.researchgate.net/figure/Gravitational-Gx-Gy-and-Gzaxes-with-respect-to-aircraft-pilot-or-astronaut_fig1_342360488

10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

Parachute Sway

As a capsule returns to earth with 

parachutes deployed, it is prone to 

swaying back and forth in the wind. 

Not only does this affect the angle 

of impact (by up to 24.50), but 

velocity of impact. The capsule will 

fall slower or faster depending on 

the angular position of the sway.

7

Shortening parachute riser length to reduce the distance between the parachute and 

payload has been shown to mitigate sway during descent. Additionally, an Over-Inflation 

Control Line reduces swing amplification by restricting the canopy diameter.

Reference: AIAA 2015-2138, Pendulum Motion in Main Parachute Clusters, Ray & Machin, April 2015

10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

8

Crew Launch Orientation

The crew launch orientation with the 

gravity vector through the chest and seat 

design can cause extreme discomfort after 

extended duration. Health impacts on the 

launch pad such as back and leg pain and 

incontinence have been experienced and 

these conditions may also persist after 

entering microgravity and/or leaving the 

seat. For this reason, the amount of time 

crew spend in this position needs to be 

limited. Using medical reports and crew 

experience, a nominal limit of 2 hours and 

45 minutes for crew to be in this position 

was decided to both be medically 

manageable and prevent significant impact 

on mission objectives. In-flight reports of 

persisting issues from the launch 

orientation have occurred after 4 hours 

crew on back time (COBT).

A time limit of 3 hours and 15 minutes was chosen based on technological capabilities and averages for 

Space Shuttle launches during the development of the Orion program. The exact time a crewmember can 

be in the launch orientation before feeling overwhelmed with the previously stated issues will vary 

between individuals and can be affected by status (e.g., hydration level, level of fatigue) before entering 

the orientation. Discomfort may be attenuated by seat design.

Orion seats

From: https://www.flickr.com/photos/nasaorion/26365220294

[V2 6113] Crew Limits in Launch 

Orientation The time in which 

crewmembers are on back with feet 

elevated in a launch configuration shall 

not exceed 3 hours and 15 minutes, 

excluding subsequent safing and egress 

time. 

From: NASA-STD-3001 Volume 2, Rev D

From: https://www.americaspace.com/2015/02/09/the-most-complex-so-farwhat-2003-might-have-been/

10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

9

Hang Time

During Orion development, discussions were held over the case 

of a “stable 2” (upside-down) landing position, which would 

introduce problems for various vehicle systems. 

After some discussion, it was decided to establish a limit for this 

position based on human physiological concerns. This led to a 

literature review and later testing to better understand the risk 

and determine the appropriate time limit.

The original stable 2 position/hang time requirement was based 

on the terrestrial analogue of hanging in a harness in a position 

that would lead to harness hang syndrome (HHS), where 

symptoms will appear after around 3.5-10 minutes, 

incapacitation after around 7-30 minutes, and eventually death.

In testing that matched the Orion crew module configuration, it 

was found that discomfort and HHS symptoms were non-issues. 

Some even found that the stable 2 position was more 

comfortable than stable 1. The observed heart rates in the fiveminute timeline did not exceed the maximum, though the rate 

for subjects that rested in the hanging position were lower than 

when attempting to egress by about 9-18%, depending on the 

exact seat configuration. The combination of crewmember 

deconditioning and bobbing in a water landing increase the risk 

of forcing a seat egress to be above that of waiting for the 

uprighting system as long as the crewmembers are 

comfortable.

[V2 6112] Hang Time Limit The system shall 

limit crew exposure to suspension trauma 

conditions to seven minutes or less. 

From: NASA-STD-3001 Volume 2, Rev D

Approximate crewmember stable 2 

position

Stable 1 capsule orientation

Stable 2 capsule orientation

Stable 3 capsule orientation

From: Barr, Y., & Fogarty, J. (2010)

10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

10

Anthropometric Considerations: Sustained Acceleration

Effects of Sustained +Az Acceleration (eyeballs down)

9.81 m/s2 Equivalent to the erect or seated terrestrial posture

19.6 to 

24.5 m/s2

Increased weight; increased pressure on buttocks; drooping of 

face and body tissues; hypotension; difficult to raise oneself at 

2.5g

29.4 to 

39.2 m/s2

Impossible to raise oneself; difficult to raise arms and legs; 

movement at right angles extremely difficult; progressive dimming 

of vision (grayout) after 3–4 seconds; progressive tunneling of 

vision 

39.2 to 

58.8 m/s2

Total loss of vision (blackout) after about 5 seconds; hearing and 

then consciousness lost if exposure continued; mild to severe 

convulsions in about 50% of the subjects after unconsciousness, 

frequently with dreams; occasionally paresthesia (abnormal nerve 

sensations, such as tingling or burning); confused states; pain not 

common, but tension and congestion of lower limbs with cramps 

and tingling; inspiration difficult; loss of orientation of time and 

space for up to 15 seconds post acceleration; after 

unconsciousness, return to purposeful action takes an average of 

24 seconds

> 58.8 m/s2 Protection is needed to preserve health

Effects of Sustained -Az Acceleration (eyeballs up)

–9.81 m/s2 Tolerable; sense of pressure and fullness in the head; congestion 

of eyes

–19.6 to -

29.4 m/s2

Severe facial congestion; bradycardia; dysrhythmia; throbbing 

headache; blurring, graying, or occasional reddening of vision 

after 5 seconds; congestion disappears slowly; may leave petechial 

hemorrhages, swollen eyelids

> –29.4 

m/s2

The 5-second tolerance limit is rarely reached; causes mental 

confusion and unconsciousness

10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

11

Anthropometric Considerations: Sustained Acceleration

Effects of Sustained +/- Ax Acceleration (eyeballs in/out)

9.81 m/s2 Slight increase in abdominal pressure; respiratory rate increases

19.6 to 

29.4 m/s2

Difficulty in spatial orientation; +2g tolerable for at least 24 hours

29.4 to 

58.8 m/s2

Progressive tightness in chest and abdomen; cardiac rhythm 

disturbances; loss of peripheral vision; difficulty in breathing and 

speaking; blurring of vision, effort required to maintain focus; 4g 

tolerable up to at least 60 minutes

58.84 to 

88.3 m/s2

Chest pain and pressure; shallow respiration from position of 

nearly full inspiration; decreased oxygen uptake during 

acceleration; pulmonary vascular pressures increase toward dorsal 

part of chest and fall in alveolar pressure on the ventral part; 

arterial oxygen saturation falls below 85%, which can lead to 

cognitive impairment; further reductions in visual acuity and 

depth perception, increased blurring, occasional tunneling, great 

concentration required to maintain focus; occasional lacrimation 

(tears); body, legs, and arms cannot be lifted at +8g; head cannot 

be lifted at +9g; precise manual control compromised

88.3 to 118 

m/s2

Increased severity of symptoms; severe breathing difficulty, 

increased chest pain, marked fatigue, loss of peripheral vision, 

diminution of central acuity, lacrimation

Effects of Sustained +/- Ay Acceleration (eyeballs left/right)

9.81 to 

18.6 m/s2

Difficulty maintaining head and shoulders upright without 

restraints; difficulty of precise manual control

27.4 m/s2

Discomfort after 10 seconds; pressure on restraint system; feeling 

of supporting entire weight on clavicle; inertial movement of hips 

and legs; yawing and rotation of head toward shoulder; petechiae 

and bruising; engorgement of dependent elbow with pain; total 

body restraint system is critical

49.0 m/s2 Conjunctival hemorrhage has been reported; severe headache 

after exposure

10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

12

Mitigation Methods: Sustained Acceleration

Anti-g suit (AGS) – The AGS provides positive pressure to the lower torso, preventing blood from pooling in 

the legs, and may also help to increase venous return. Venous occlusion and discomfort may be 

problematic. Studies show that although the AGS is good for short-duration g exposure, it may actually 

decrease tolerance for durations greater than several seconds.

Muscle contraction – Straining and tensing muscles raises the G-LOC threshold by constricting the body’s 

vasculature, thereby preventing blood from traveling away from the head when in an upright position.

Lower-body negative pressure (LBNP) – LBNP stresses the cardiovascular system on orbit by creating a 

controlled pressure differential between the upper and lower body. The heart responds by increasing blood 

pressure to maintain proper blood flow to the head and upper body. It is possible that periodic exposure to 

LBNP may reduce the amount of cardiovascular deconditioning, thereby increasing orthostatic tolerance 

during entry. 

L-1 AGSM – This procedure includes muscle contraction and repeating the Valsalva maneuver and a short, 

deep breath every 3 to 4 seconds. It gives substantial protection by raising blood pressure at head level. 

Negatively, it tends to be very fatiguing and distracts the pilot from other tasks. 

Positive-pressure breathing – This procedure is less fatiguing than the L-1 maneuver or using an AGS, but it 

can cause difficulty when trying to communicate.

Entry fluid loading –In a sample of 26 astronauts, the 17 who practiced “fluid loading,” or drank 1-2 L of 

high-sodium liquids before entry, had lower heart rates, maintained blood pressure better, and reported no 

faintness, compared to 33% incidence of faintness in the 9 astronauts who did not use the countermeasure. 

However, it seems that the effectiveness of fluid loading is reduced as mission duration increases.

Pharmacotherapeutics – Certain medications may improve orthostatic intolerance by increasing peripheral 

vasoconstriction, plasma volume, or cardiac contractility.

Air force anti-G suit

From: https://www.luke.af.mil/News/ArticleDisplay/Article/358586/new-g-suit-comes-to-luke/

LBNP device in use on Skylab

From: 

https://commons.wikimedia.org/wiki/File:Skylab_3_Garriott_in_Lowe

r_Body_Negative_Pressure_Device.jpg

10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

13

Mitigation Methods: Transient Acceleration

Restraint system – In the absence of proper restraint, 

whiplash and submarining injuries of the spinal column 

may occur. Restraint systems may affect operations by 

being complex to don and restricting the occupant’s 

mobility.

Couches – Human tolerance to impact improves when the 

contact area between the body and restraint system is 

greater. Rigid, individually contoured couches were used in 

the early U.S. space program and in the current Russian 

Soyuz capsule. This approach ensures that each external 

body segment will be simultaneously decelerated on 

landing and that the support pressure gradients exerted 

on the body surfaces will be minimized. Some previous 

designs have been uncomfortable because only one body 

position matched the contour, which also made different 

types of movement difficult.

Crushable structure – It is important to consider that the 

spacecraft itself could provide reduction of impact forces, 

with the use of structural design and materials that can 

absorb energy upon being crushed.

Stroking seats – The Apollo Command Module included a 

crew couch/frame that was supported in the crew module 

by struts and had built-in Y-Y struts to stroke, to attenuate 

landing loads for water landings and potential hard landing 

during aborts. However, this added design complexity and 

created unpredictable secondary dynamics.

Retrorockets – The Russian Soyuz uses retrorockets in 

addition to contoured couches. After entry, the heat shield 

is discarded, exposing six retrorockets, four of which are 

automatically fired at about 1 m (~3 ft) above the ground. 

The other two rockets may be activated in the event of an 

off-nominal entry.

Airbags – Before splashdown, the Mercury capsules had 

the heat shield drop to extend a landing bag, or an impact 

skirt, under the spacecraft to help dampen landing loads 

imparted to the crew.

Apollo stroking seat design

From: 

https://space.stackexchange.com/questions/46746/whydid-the-apollo-capsule-have-seats-if-the-astronautsnever-were-sitting-in-it

Soyuz retrorockets firing

From: 

https://www.nasa.gov/content/expedition36-soyuz-landing

Mercury impact skirt design

From: https://en.wikipedia.org/wiki/Project_Mercury

10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

14

Anthropometric Considerations: Rotational Motion

Effects of Rotational Motion About Any Axis

6 rpm Most individuals without previous experience can tolerate this rotation 

in any axis or combination of axes

> 6 rpm Most individuals rapidly become sick and disoriented unless carefully 

prepared by a graduated program of exposure

12 to 30 rpm Most individuals cannot initially tolerate rotation

random tumbles Severe disorientation; reach and manipulative performance degradation 

ultimately interfere with the ability to make corrective actions

Effects of Rotational Motion about the Pitch Axis

6 rpm Some individuals have endured 60-minute runs

80 rpm

Generally intolerable; with the center of rotation at heart level, 

symptoms of backward acceleration (–Gx) are demonstrated and are 

tolerable for only a few seconds

90 rpm

Some effects of forward acceleration (+Gx), namely numbness and 

pressure in the legs, are also observed but develop slowly, with pain. No 

confusion or loss of consciousness is found, but in some individuals, 

disorientation, headache, nausea, or mental depression are noted for 

several minutes after a few minutes of exposure

160 rpm Unconsciousness from circulatory effects alone occurs after 3–10 

seconds with the center of rotation at the heart

180 rpm Unconsciousness from circulatory effects alone occurs after 3–10 

seconds with the center of rotation at the iliac crest (hip bone)

Effects of Rotational Motion about the Yaw Axis

60 to 90 rpm

When the head and trunk are inclined forward out of the z-axis, rotation 

becomes close to limiting for 4 minutes, although some motivated 

individuals have endured 90 rpm in the same mode. Except for unduly 

susceptible individuals, tolerance tends to improve with exposure

90 to 100 rpm Intolerable

Depending on the magnitude and duration of 

the rotational motion, countermeasures may 

include:

• The use of a g-suit to prevent excessive 

peripheral blood flow

• Restraints to prevent flailing

• Minimizing head movement to reduce 

Coriolis stimulation of the vestibular 

system, which could cause severe 

disorientation

Coriolis stimulation representation

From: https://www.researchgate.net/figure/Scheme-of-the-Coriolis-crosscoupling-stimulus-and-the-induced-sensory-conflict-A_fig1_294732031

10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

15 10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

• Updated information to reflect additions to NASA-STD-3001 

Volume 2

• Added slides on crew launch orientation and hang time

• Updated HIDH references to be consistent with revision

Original  Rev A

• Updated information to be consistent with NASA-STD3001 Volume 1 Rev B and Volume 2 Rev C

Major Changes Between Revisions

16 10/04/2023

Rev C
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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 6064] Sustained Translational Acceleration Limits The system shall limit the magnitude, direction, 

and duration of crew exposure to sustained (> 0.5 seconds) translational acceleration by staying below the 

limits in Figures 6.5-(2-7) and Tables 6.5-(1-6) for seated and standing postures. 

[V2 6065] Rotational Velocity The system shall limit crew exposure to rotational velocities in yaw, pitch, 

and roll by staying below the limits specified in Figure 6.5-8—Rotational Velocity Limits and Table 6.5-7—

Rotational Velocity Limits.

[V2 6066] Sustained Rotational Acceleration Due to Cross-Coupled Rotation The system shall prevent the 

crew exposure to sustained (>0.5 second) rotational accelerations caused by cross-coupled rotations 

greater than 2 rad/s2.

[V2 6067] Transient Rotational Acceleration The system shall limit transient (≤0.5 seconds) rotational 

accelerations in yaw, pitch, or roll as specified in Table 6.5-8—Head CG Rotational Acceleration Limits, to 

which the crew is exposed. The limits are appropriately scaled for each crewmember size from the 50th

percentile male limits of 2,200 rad/s2 for nominal and 3,800 rad/s2 for off-nominal cases. 

[V2 6069] Acceleration Injury Prevention The system shall mitigate the risk of injury to crewmembers 

caused by accelerations during dynamic mission phases per Table 6.5-9—Acceptable Injury Risk Due to 

Dynamic Loads. 

[V2 6070] Injury Risk Criterion The system shall limit crew exposure to transient translational acceleration 

(≤0.5 seconds) by limiting the injury risk criterion (β/beta) to no greater than 1.0 (Low) for seated or 

standing crew as defined by Dynamic Response (DR) limits in NASA/TM-20205008198 Table 2 “Updated 

Dynamic Response Limits for Standing”, while crew are restrained as required in NASA/TM-2013-

217380REV1 for seated crew, or NASA/TM – 20205008198 for standing crew.

[V2 6111] Dynamic Mission Phases Monitoring and Analysis The system shall collect vehicle and 

crewmember acceleration parameters, specific kinematic responses, and associated metadata, during all 

dynamic mission phases and suited operations (defined as ascent, abort, entry, descent, landing, 

postlanding, and EVA operations) to correlate with any injuries incurred by crewmembers.

[V2 6112] Hang Time Limit The system shall limit crew exposure to suspension trauma conditions to 

seven minutes or less. 

[V2 6113] Crew Limits in Launch Orientation The time in which crewmembers are on back with feet 

elevated in a launch configuration shall not exceed 3 hours and 15 minutes, excluding subsequent safing

and egress time.

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

Referenced Technical Requirements

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

OCHMO Standards website
NASA-STD-3001 Technical Brief

OCHMO-TB-024

Acceleration

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

1. Thyagarajan, R., Ramalingam, J., & Kulkarni, K.B. (2014). Occupant-Centric Platform (OCP) TechnologyEnabled Capabilities Demonstration (TECD) Comparing the Use of Dynamic Response Index (DRI) and 

Lumbar Load as Relevant Spinal Injury Metrics. U.S. Army Tank Automotive Research, Development, 

and Engineering Center Detroit Arsenal. https://apps.dtic.mil/sti/pdfs/ADA591409.pdf

2. Human Integration Design Handbook (HIDH). (2014). NASA/SP-2010-3407/REV1. 

https://www.nasa.gov/organizations/ochmo/human-integration-design-handbook/

3. Somers, J.T., Gohmert, D., & Brinkley, J.W. (2017). Application of the Brinkley Dynamic Response 

Criterion to Spacecraft Transient Dynamic Events. NASA/TM-2013-217380-REV1. 

https://ntrs.nasa.gov/api/citations/20170005913/downloads/20170005913.pdf

4. Ray, E.S., & Machin, R.A. (2015). Pendulum Motion in Main Parachute Clusters. Aerodynamic 

Decelerator Systems Technology Conferences. https://eric.mnray.net/data/cpas/AIAA-2015-

2138_Pendulum.pdf

5. Somers, J.T., et al. (2020). Artemis Sustained Translational Acceleration Limits: Human Tolerance 

Evidence from Apollo to International Space Station. NASA/TM-20205008196. 

https://www.nasa.gov/wp-content/uploads/2023/03/tm-20205008196.pdf

6. Barr, Y., & Fogarty, J. (2010). Assessment of Prone Positioning of Restrained, Seated Crewmembers in a 

Post Landing Stable 2 Orion Configuration. JSC-CN-19414. 

https://ntrs.nasa.gov/api/citations/20100005137/downloads/20100005137.pdf

7. National Aeronautics and Space Administration (2007). Space Flight Human System Standard. NASASTD-3001. https://www.nasa.gov/directorates/esdmd/hhp/human-spaceflight-and-aviationstandards/

8. Tripp, L. (2007). Assessment of Gravito-Inertial Loads Environment (AGILE) Workshop. Houston, TX.

9. Bungo, M.W., Charles, J.B., & Johnson, P.C. Jr. (1985) Cardiovascular Deconditioning During Space Flight 

and the Use of Saline as a Countermeasure to Orthostatic Intolerance. Aviat Space Environ Med, 

56(10), 985-90.

10. Charles, J.B. & Lathers, C.M. (1991) Cardiovascular adaptation to spaceflight. J. Clin. Pharmacol, v. 31, 

p. 1010-1023, 1991.

11. Evidence Report: Risk of Injury Due to Dynamic Loads. Human Research Program. Sept 15, 2021. 

https://humanresearchroadmap.nasa.gov/evidence/reports/OP%20Dynamic%20Loads%20EB%20FIN

AL_11-30-22.pdf?rnd=0.0755836554223595

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