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1 OF 23NASA 2009 Project Management Challenge EC5/D. Gohmert/281-483-9350

CEV Seat Concept Design

The CEV Seat: Seeking a Custom Fit

in an Off-the-Rack World

Dustin GohmertCREW AND THERMAL SYSTEMS DIVISION

NASA Project Management Challenge24 Feb. 2009

EC5/D.Gohmert281-483-9350


CEV Seat Concept DesignMotivation

• 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.


CEV Seat Concept DesignSeat Design Basic Requirements and Needs1. Occupant Protection

1. Conformal support2. Hip bolsters3. Shoulder bolsters4. Head bolsters5. Load-distributing harness

2. Adjustable Fit for All Sizes1. Seated height (shoulder height)2. Shoulder breadth3. Buttocks to popliteal4. Popliteal height5. Hip breadth

3. Stowable1. Reconfigurable for on-orbit maximization of volume

4. Multipurpose1. Operator seats2. Non-operator seats

5. Reliable1. Technologies and materials proven for spaceflight2. Minimal failure modes

6. Lightweight

Seat Layout Views


CEV Seat Concept DesignBaseline 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


CEV Seat Concept DesignWhat Can We Learn from Industry?

• Highly conformal, custom-fit seats save lives and improve performance


CEV Seat Concept DesignBut…

• 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.


CEV Seat Concept DesignChallenge - 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.


CEV Seat Concept DesignChallenge 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.

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CEV Seat Concept DesignSeat 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.


CEV Seat Concept DesignSmall 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


CEV Seat Concept DesignLateral 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


CEV Seat Concept DesignThigh 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.


CEV Seat Concept DesignShoulder and Head Support Assembly

• Single assembly that provides:– Headrest – lateral support wings with fabric “hammock” for head support

sized to helmet diameterNOTE: 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


CEV Seat Concept DesignHand 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.


CEV Seat Concept DesignAdjustability

Small Occupant ConfigurationLarge Occupant Configuration


CEV Seat Concept DesignACES Suited Fit


CEV Seat Concept DesignTips 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!


CEV Seat Concept DesignConcept Testing

• High G Sled Testing at Wright Patterson AFB

Zoom Zoom!


CEV Seat Concept DesignConcept Testing

• 0 Gravity Testing

Seat Functionality Evaluations

0g Spinal Growth Evaluations


CEV Seat Concept Design3D 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


CEV Seat Concept DesignWhere We Have Gone From There

Lockheed Martin Export Controlled

Lockheed Martin/NASA Orion Seat Design Evolution


CEV Seat Concept DesignExamples 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)


CEV Seat Concept DesignExamples 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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