Behrendsen, Robert R.

NASA Technical Reports Server

Ergonomics and Human Factors for the
Restraints and Mobility Aids on the
International Space Station
Robert Behrendsen
25 April 2013
https://ntrs.nasa.gov/search.jsp?R=20130013008 2019-08-31T01:10:00+00:00Z
Overview
• Space Flight Environment
• The ISS Restraints and Mobility Aids
• Ergonomics and Human Factors for 
Space flight
• Suggested Improvements
• Recommendations
Space Flight Environment
• Which direction is up?
• Zero Gravity
o Translations
o Station Keeping
• Operations 24/7 
o Working Laboratory 5/8
o Off Duty time
• Crew time cost escalated annually
o $65,000 – $95,000/hr
International Space Station (ISS) Restraints and
Mobility Aids
• How do crew members get around and secure themselves?
o Handrails
• USOS
• Russian
o Foot Restraints
• Short Duration
• Long Duration
• Cupola Crew Restrains
o Tethers
• Bungees
• Straps
• Harness
o Shoes/Socks
International Space Station (ISS) Restraints and
Mobility Aids
• USOS
Handrails
International Space Station (ISS) Restraints and
Mobility Aids
• USOS
Handrails
International Space Station (ISS) Restraints and
Mobility Aids
• Russian
SM/Handrails
Bungee
International Space Station (ISS) Restraints and
Mobility Aids
• Russian
FGB/Handrails
Bungee
International Space Station (ISS) Restraints and
Mobility Aids
• USOS
Foot 
Restraints
International Space Station (ISS) Restraints and
Mobility Aids
• USOS
Cupola
Crew 
Restraints
International Space Station (ISS) Restraints and
Mobility Aids
• Strap/bungee
• Slippers/socks
International Space Station (ISS) Restraints and
Mobility Aids
• Harness
• Exercise shoes
Ergonomics and Human Factors for 
Space flight
• Body posture
o Neutral position
• Muscles/Forces and Reactions
o Translations or relocation via handrails
• Primary movement with fingers, hands, arms, and 
shoulders
• Secondary with toes, feet, legs, stomach, and back
o Station keeping
• Primary with toes, feet (top), legs (shin), stomach, back
• Secondary with fingers, hands, arms, and shoulders
Ergonomics and Human Factors for 
Space flight
• Repetitive and/or continuous use of muscles, tendons, joints, and bones can 
cause crew injuries or disorders
o Cumulative Trauma Disorders (CTDs)
o Repetitive Strain Injuries (RSIs)
o Musculoskeletal Disorders (MSDs)
• The medical history of ISS crew members is not identified in this report; 
however, the possible injuries that the ISS crew members could suffer from 
operational R&MA 
o Back Pain 
o Shin Splints
o Stress Fracture
o Tendinosis or Tendinitis – Achilles, Patellar
o Compartment  Syndrome
Ergonomics and Human Factors for 
Space flight
• Crew comments from debriefs related to ergonomics
o “a lot of times you are reacting ….with the top of your feet beneath the 
handrail ….. just the act of typing for a length of time with your feet 
constantly having to pull you back in”
o “typing on a laptop ....  They found it to be a bit troublesome because 
you are reacting that force, not with your mass sitting in a chair, but 
with your feet and the small muscles in the front of your shins”
o “You spend an hour or two holding yourself in place with the little 
muscles on the front of your shins and it hurts.”
Ergonomics and Human Factors for 
Space flight
• Crew comments from debriefs related to hardware
o “The crew wanted to have a foot restraint ….with foam wrapped on it, 
and they could do this with the CTB dividers”
o “The crewmember attached a bungee at the end of the handrail that 
their feet were under, had the bungee around their hips, wrapped their 
legs around each side and was locked in and typing.”
o “the WHC foot restraint, all the mechanisms come loose eventually and 
pop off with the way it clamps on the handrail”
o “crewmember disliked the banisters and questioned if it was because 
they didn’t understand the intent of them”
Ergonomics and Human Factors for 
Space flight
• Human Factors consideration on the design boundary for reach
Ergonomics and Human Factors for 
Space flight
• Human Factors consideration on the design boundary fwd/aft
Ergonomics and Human Factors for 
Space flight
• Human Factors consideration on the design boundary side-side
Ergonomics and Human Factors for 
Space flight
• Human Factors consideration on the design boundary line of sight
Suggested Improvements
• Provide adequate R&MA and Training to improve Operational 
environment and realize the return on investments
o New Hardware
o Modified existing hardware
o Physical Training Plans
Suggested Improvements
• New hardware for consideration
o Harness with adjustable hydraulic dampener or simply elastic straps 
that is easy to use
o Foot rails with adequate padding that stay secured and not loosen with 
continued use
o Padding for current Handrails
Suggested Improvements
• Modified hardware for consideration
o Harness with retractable tether or bungee  straps
o CTB dividers for added padding on current Handrails
Suggested Improvements
• Physical Training Plans
o Primary objective is to increase flexibility and muscle strength focusing 
on the toes, up foot motion, and shin area (dorsiflexion angles)
o Secondary objective is to focus on legs, hips, back, stomach, arms 
shoulders, hands
o Maintain a good respiratory rate and eat healthy
Recommendations
• What is the cost, will it solve the issues, and will the crew use it?
o New Hardware (Harness, Foot rail, Padding)
• Foot rail provides the best benefit with minimal cost and 
easy to use
o Modified Hardware (Harness, Padding)
• Padding for hand rails easy to implement and use; 
however, needs crew time
o Physical training
• Add angle dorsiflexion to crew physical training plan
Questions?
References
• International Space Station Flight Crew Integration Standard 
(NASA−STD−3000/T) SSP 50005 Revision E; 30 June 2006; National 
Aeronautics and Space Administration
• Occupational Safety & Health Administration (OSHA), Analysis Tools; On line at 
http://www.osha.gov/SLTC/ergonomics/analysis_tools.html
• Price per crew hour; Correspondence with ISS Vehicle Chief Engineer via NASA 
e-mail
• Crew Debrief Questions Database; NASA Habitability and Human Factors 
Division
• ISS Downlink Imagery Collection; On line http://images.jsc.nasa.gov/
• Physical training plan; Correspondence with Crew Trainer via phone call


Ergonomics and Human Factors for the Restraints and Mobility Aids on the International Space Station

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