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National Aeronautics and Space Administration
Advanced Space Suits
Amy Ross
NASA-Johnson Space Center
Society for the Advancement of
Material and Process Engineering
Long Beach, CA
May 26, 2016 www.nasa.gov/exploration
What I’ll Talk About
A brief introduction
Space suit pressure garments: What they are
and do
Materials used in space suits
Space suit design challenges
Questions
A brief introduction
Overarching objective
Provide best tool to crew for extravehicular activities during human
space exploration missions
[MARS OR BUST!]
Scope of work: Lead NASA’s advanced pressure garment development
– Requirements definition
– Technology development, component level development
– Testing
– Certification for use in test and eventually for flight
Team: BIGGEST we’ve ever been
• 6 civil servants
• 2 rotational engineers
• 4 technicians
• 4 contractor engineers
Basics: Why Do You Need an EVA Suit?
4
Space Suits Provide 3 Basic Functions For EVA Astronauts:
1
First, in conjunction with a portable life support
system, the space suit maintains the physiological
well-being of the astronaut
• Supplying oxygen for pressurization, breathing, and ventilation
• Provide carbon dioxide and metabolic heat removal
2 Secondly, the space suit incorporates various mobility
joint systems to enable the astronaut to perform EVA
tasks in the pressurized condition
• Includes both dual-axis and single axis joints and bearings
3
Finally, the space suit provides protection
against the hazards of the particular EVA
environment
• Thermal extremes
• Meteoroid and orbital debris
• Radiation conditions
• Abrasion and sharp edges
• Sand, dust, and rocks
In essence, the space suit is a
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small spacecraft in itself
What Does a Planetary
Walking Suit Look Like?
5 A space suit consists of
two main components:
a pressure garment
that covers your body
and a life support
system that can be
worn on your back
Pressure garments are
what we typically think
of as a “space suit”,
while the PLSS is that
ill-defined box nobody
pays much attention
to…except, of course, if
you’re in the pressure
garment…
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What Does a Planetary Walking
Suit Look Like?
6
Rear-entry
Helmet angled and shaped for wide field view,
including downward visibility
Hard or soft torso, briefs and hip
Waist bearing and flexion/extension joints
Hip mobility joint system with 2 or more bearings
and features for adduction/abduction
Softgood arms and knees
Walking boots with an ankle flexion/extension joint
and ankle bearing
Environmental protection garment that addresses
dust,
Durability with UV radiation exposure,
Thermal protection in a low atmospheric pressure,
Durability with exposure to products of chemical react
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Suits will be flexible and rugged enough to bend over, dig holes, walk up hill to
the outcrop, bash rocks, collect and stash samples, and look closely at rock
specimens.
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Materials used in Space Suits
Softgoods lay-up
Metals
– Stainless steel,
aluminum,
titanium
Composites
– Z-2 composites
include PW IM-
10 sandwiched
in 8HS S-2
glass
Plastics
– Polycarbonate
8
EMU Suit Layers
Outermost Innermost
Pressure Garment
Bladder - urethane coated
nylon oxford fabric
Pressure Garment
Cover-Restraint - dacron
TMG Liner – neoprene
coated nylon ripstop
TMG Insulation – 5-7
layers of aluminized mylar
Thermal Micrometeoroid
Garment (TMG) Cover
Space Suit Design Challenges
Defining requirements for a unique application using standard test methods
“Outer Layer Cut Resistance” requirement
– Tested current outer layer materials, Orthofabric and
Polytetrafluoroethylene (PTFE) fabric
• ASTM F1790-05 “Standard Test Method for Measuring Cut
Resistance of Materials”
• Testing against a standard is attractive:
– clearly defined verification method to a quantitative value.
Flaw: Doesn’t necessarily address the needed performance for the new
system because it only quantifies current performance within the specific
scope of the test and because extrapolation could be imperfect.
• “What if the test standard selected does not characterize the
attribute of the current material that provides the desired
performance?”
• "What if the test standard does not accurately represent the
environment/conditions that the hardware would actually be
exposed to?"
10
Space Suit Design Challenges
Defining requirements for a unique application using customized test methods
Develop a test protocol that
directly addresses the
performance in question
– Effort to modify ASTM D 3884-
01 “Standard Guide for Abrasion
Resistance of Textile Fabrics
(Rotary Platform, Double Head
Method)”,
• added measured quantities of
lunar simulant JSC-1 to the
wheel abrasion test.
Flaw: protocol was tested
separately at Glenn Research and
Johnson Space Centers, results
did not correlate ASTM D 3884-01 test device
11
Space Suit Design Challenges
Another customized test: tumble test
development.
– Cylinders of current and candidate
materials were tumbled in a rotary drum
with simulated rocks and simulant dust.
• Before and after testing a visual
inspection, material strength
(tensile and tear) tests, and
scanning electron microscope
(SEM) images were performed.
Method recently revised using squares or
lay-ups of material secured to the inside
surface of the rotary drum in an effort to
increase the efficiency of the test.
Flaw: method provides significant
comparative information, but has not Rotary Drum test device
resulted in a clear quantitative
requirement.
12
Space Suit Design Challenges
Space suit must be strong,
durable, and light-weight
-Approach: replace stainless
steel bearings with titanium
Issue: oxygen compatibility
-Approach: cycle testing in
oxygen environment at White
Sands Test Facility
Obtained proof of oxygen
compatibility, but discovered
new issue:
-wear
13
Additional Space Suit Design Challenges
Durability/cycle life requirements
– For a human mission to Mars: ~ 106 walking cycles
Radiation Environment
– Materials life
– Do no additional harm
Composites
– Impact requirements
– Manufacturability of composites
• In or out of autoclave
• Availability/cost
• Time of manufacture
• Quality assurance
• Metal to Composites interfaces
Secondary impactors
14
National Aeronautics and Space Administration
References:
Ross, Amy, Lindsay Aitchison, Richard Rhodes, “Advanced Extra-
vehicular Pressure Garment Requirements Development”, ICES-2015-
031, 45th International Conference on Environmental System, ICES,
Inc., Bellevue, WA; July 2015.
Rhodes, Richard, Brian Basttisti, Raymond Ytuarte, Bradley Schultz,
“Development and Evaluation of Titanium Spacesuit Bearings”, ICES-
2016-60, 46th International Conference on Environmental System,
ICES, Inc., Vienna, Austria; July 2016.
https://www.nasa.gov/suitup
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