1. CEV Seat Concept Design
The CEV Seat:
Seeking a Custom Fit
in an Off-the-Rack World
Dustin Gohmert
CREW AND THERMAL SYSTEMS DIVISION
NASA Project Management Challenge
24 Feb. 2009
EC5/D.Gohmert
281-483-9350
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2. CEV Seat Concept Design
Motivation
• Seat design does not fully support the occupant for off-nominal landings.
– Lack of lateral support
– Lack of full leg support for all occupants
• Race-car seat concepts are supportive—but require customization to fit occupant.
– Do not provide leg supports
– Do not allow for feasible egress in emergency scenario
• No design exists that meets implicit and explicit needs of a CEV seat system.
• I needed something to do over the holidays…
OBJECTIVE
• To design a simple seat concept that provides full occupant support in all axes for
the full range of occupant sizes without fully custom components for each person.
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3. CEV Seat Concept Design
Seat Design Basic Requirements and Needs
1. Occupant Protection
1. Conformal support
2. Hip bolsters
3. Shoulder bolsters
4. Head bolsters
5. Load-distributing harness
Seat Layout
2. Adjustable Fit for All Sizes Views
1. Seated height (shoulder height)
2. Shoulder breadth
3. Buttocks to popliteal
4. Popliteal height
5. Hip breadth
3. Stowable
1. Reconfigurable for on-orbit maximization of volume
4. Multipurpose
1. Operator seats
2. Non-operator seats
5. Reliable
1. Technologies and materials proven for spaceflight
2. Minimal failure modes
6. Lightweight
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4. CEV Seat Concept Design
Baseline Seat Concept
• 90/90 hip/thigh angles
• Non-operator legs must be raised toward chest to fit in vehicle spacing
• Minimal lateral support
• Stowable
• Lightweight
• HOWEVER, IT DID MEET THE MINIMAL REQUIREMENTS WE HAD SET FORTH
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5. CEV Seat Concept Design
What Can We Learn from Industry?
• Highly conformal, custom-fit seats save lives and improve performance
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6. CEV Seat Concept Design
But…
• You can’t get out of them when you are on your back or in a space-suit…
• And they only fit the person they were designed for.
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7. CEV Seat Concept Design
Challenge - Leg Curvature
• Problem: Flat seats are flat, humans are not.
– Models cannot adequately convey the conformity of a human.
– In a +Z impact the body is going to find those empty spaces and fill them.
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8. CEV Seat Concept Design
Challenge Leg Length Differences
• Problem: We have to accommodate varying thigh and lower leg lengths—but the
seat and Orion inner mold line (the walls) do not move.
– Means that legs of persons with longer lower legs must have thighs pulled farther
toward chest.
IML Spacing Line
Seat Bottom
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9. CEV Seat Concept Design
Seat Concept
• Pulls together the best features of the designs that we examined, and modified the
features to work in a recumbent posture with a space suit.
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10. CEV Seat Concept Design
Small Female vs. Large Male Fit
• Spacer pads added at shoulders and hips to provide
semi-custom, conformal lateral fit
• Maximum shoulder spacer app. 3.5” each side
Conformal Spacer Pads
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11. CEV Seat Concept Design
Lateral Support
• Full lateral support at primary load paths of pelvis and shoulders
– Exact principles applied in race-car seat designs.
• Additional lateral support at knees, head, and feet.
Areas of Lateral Support
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12. CEV Seat Concept Design
Thigh Panel Extension Assembly
• Curved thigh extension
• Mates to curved groove of hip panel—curve
is essential to maintain path of motion
• As thigh panel is lengthened, knee pivot is
moved up in the Z axis automatically.
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13. CEV Seat Concept Design
Shoulder and Head Support Assembly
• Single assembly that provides:
– Headrest – lateral support wings with fabric “hammock” for head support
sized to helmet diameter
NOTE: lateral wings should nominally be taller and the hammock should be deeper than in
prototype. I estimated wrong in my first stab at it…
– Lateral shoulder supports
pads added to decrease span for smaller occupants
– Shoulder belt anchor points
– Anti-elongation support
Provides support to keep occupant from elongating in a –Z impact
• Adjusts as single unit to occupants seated mid-shoulder height
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14. CEV Seat Concept Design
Hand Controller Mounts
• Hands naturally fall at knees when seated recumbently.
• Seat structure is near hand area, so why not use it as a mounting point?
• Eliminated need for separate armrest
– Eliminates egress obstruction
– Eliminates stability issues associated with cantilevered armrest
• May rotate out of the way for egress
• Hand controller mounts must be extendable down toward pallet to accommodate varying
forearm lengths.
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15. CEV Seat Concept Design
Adjustability
Large Occupant Configuration Small Occupant Configuration
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16. CEV Seat Concept Design
ACES Suited Fit
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17. CEV Seat Concept Design
Tips that Helped in the Process
• Keep an Open Mind
– It is easy to become close-minded with a singular focus just because the status quo is comfortable.
– Challenge yourself to step past that comfort zone to question if what you are doing can be improved.
• Listen to the ideas of others – even if you think the idea is not sound
– The conformal seat was a very good idea, but we knew it would not work so we discounted it for a while and
settled into a comfort zone with what we had.
– Had we not given the work of others a fair and fresh look, the current concept would have never emerged.
• Don’t Fall into a Computer-Designed Trap
– Computer tools like CAD and FEA are nice, but not without some good old-fashioned common sense
behind them. They should not be the only tool in the toolbox.
– Sometimes pure hands-on creativity and gruntwork allows you to find the hidden pitfalls that are buried
behind the pixels.
• Understand What You are Trying to Do
– Fundamentally and in self-actualizing detail, not just the “lawyered-up” requirements language that is given
to you.
– Were we building a seat or was a seat the design solution to keeping the crew safe in a landing? Once the
latter was understood, then the seat became something so much more than just a perch for a posterior.
• Don’t Be Afraid to Take a Chance on Your Own to Make a Change
– The squeaky wheel gets the grease, so sometimes it is okay to cause a ruckus.
– But that wheel is still only part of the greater vehicle – don’t alienate others in the process, since you are
still part of something greater than just you.
• Have Fun!
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18. CEV Seat Concept Design
Concept Testing
• High G Sled Testing at Wright Patterson AFB
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19. CEV Seat Concept Design
Concept Testing
• 0 Gravity Testing
0g Spinal Growth Evaluations
Seat Functionality Evaluations
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20. CEV Seat Concept Design
3D Human Scanning:
• I know I said I hated computer models, but…
– This was more accurate than tracing my rear-end on cardboard
• Used to refine shape of seatpan to fit full crew complement
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21. CEV Seat Concept Design
Where We Have Gone From There
Lockheed Martin/NASA Orion Seat Design Evolution
Lockheed Martin Export Controlled
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22. CEV Seat Concept Design
Examples of Design Concept Exploration
• Currently searching for a way to integrate auxiliary
breathing air onto a person seated in a semi-
conformal seat.
Legacy designs prevent proper
integration to conformal fitting
seats.
Firetruck seat with integrated
mounts for Self Contained
Breathing Apparatus (SCBA)
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23. CEV Seat Concept Design
Examples of Design Concept Exploration
• Heel Mounting Design Concept Exploration
– Cycling Shoes and Clipless Pedals
If all else fails I can now seek work as a cobbler…
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