The constellation program is evaluating current vehicle design capabilities for nominal water landings and contingency land landings of the Orion Crew Exploration vehicle. The Orion Landing Strategy tiger team was formed to lead the technical effort for which associated activities include the current vehicle design, susceptibility to roll control and tip over, reviewing methods for assessing occupant injury during ascent / aborts /landings, developing an alternate seat/attenuation design solution which improves occupant protection and operability, and testing the seat/attenuation system designs to ensure valid results. The EVA physiology, systems and Performance (EPSP) project is leading the effort under the authority of the Tiger Team Steering committee to develop, verify, validate and accredit biodynamics models using a variety of crash and injury databases including NASCAR, Indy Car and military aircraft. The validated biodynamics models will be used by the Constellation program to evaluate a variety of vehicle, seat and restraint designs in the context of multiple nominal and off-nominal landing scenarios. The models will be used in conjunction with Acceptable Injury Risk definitions to provide new occupant protection requirements for the Constellation Program

Gernhardt, Michael L.

Granderson, B. K.

Jones, J. A.

Somers, J. T.

NASA Technical Reports Server

Occupant Protection During Orion Crew Exploration Vehicle Landings  
M.L. Gernhardt1, J.A. Jones1, B.K. Granderson2, J.T. Somers2 
1NASA Johnson Space Center, 2101 NASA Parkway, Houston, TX 77058 
 2Wyle Integrated Science & Engineering Group, 1290 Hercules Dr. Houston, TX 77058 
Introduction  The Constellation Program is evaluating current vehicle design capabilities for nominal water 
landings and contingency land landings of the Orion Crew Exploration Vehicle.  The Orion Landing Strategy Tiger 
Team was formed to lead the technical effort, for which associated activities include the current vehicle design 
susceptibility to roll control and tip over, reviewing methods for assessing occupant injury during 
ascent/aborts/landings, developing an alternate seat/attenuation design solution which improves occupant protection 
and operability, and testing the seat/attenuation system designs to ensure valid results.  The EVA Physiology, 
Systems, and Performance (EPSP) Project is leading the effort under the authority of the Tiger Team Steering 
Committee to develop, verify, validate and accredit biodynamics models using a variety of crash and injury 
databases, including NASCAR, Indy Car, and military aircraft.  These validated biodynamics models will be used 
by the Constellation program to evaluate a variety of vehicle, seat, and restraint designs in the context of multiple 
nominal and off-nominal landing scenarios.  These models will be used in conjunction with Acceptable Injury Risk 
definitions to provide new occupant protection requirements for the Constellation program.   
Biodynamics Modeling  Race car and military aircraft occupant protection experience suggests significant benefits 
can be gained from improved seat and restraint systems. Existing NASA occupant protection requirements are tied 
to the Brinkley injury risk model, which cannot adequately account for seat/restraint systems and their associated 
injury responses to a range of landing loads.  The EPSP team is coordinating a panel of subject matter experts from 
auto, racing and military occupant protection backgrounds.  The acquisition, processing and modeling of statistical 
and biodynamic data will be undertaken by the team and reviewed with this expert panel.  In addition, the team is 
responsible for sharing knowledge captured within the project data analysis with the Steering Committee and the 
Orion project for design and requirements impacts.  The team will organize the final project deliverables, validated 
biodynamics models and report to the Constellation program in time to support critical design review milestones for 
the Orion project. 
Definition of Acceptable Risk
 
  After defining probability of injury associated with critical biodynamic responses, it 
is necessary to systematically define the highest level of acceptable injury risk during landings consistent with a 
successful program.  This definition is based on key mission drivers such as crew health, safety and performance 
considerations in the immediate landing environment, long-term crew health considerations including medical 
policy and future flight status, programmatic success criteria e.g. overall Loss of Crew (LOC) requirement in context 
of all mission phases, public opinion and ethical considerations, and balancing the risk vs. reward (Utility) for 
landing environment in context of all mission phases.  To put Orion landing risk in perspective, the team is 
providing a context of injury risk compared with other military and civilian vehicle operations based on overall risk 
of injury, probability of an off-nominal event, and the risk of injury in an off-nominal event.  To accomplish this 
task, an Operationally Relevant Injury Scale is being defined to allow classification of injuries based on impacts to 
crew performance and egress. 
https://ntrs.nasa.gov/search.jsp?R=20090007555 2019-08-30T06:07:06+00:00Z
Page 1Operations Integration All Hands - 11/12/2007
Occupant Protection During Orion Crew 
Exploration Vehicle Landings 
M.L. Gernhardt, J.A. Jones, B.K. Granderson, J.T. Somers
NASA Johnson Space Center &
Wyle Integrated Science & Engineering Group
Houston, TX 77058
Page 2
Origination
• The Constellation Program is evaluating current vehicle design 
capabilities for nominal water landings and contingency land 
landings of the Orion Crew Exploration Vehicle.  
• The Orion Landing Steering Committee (LSC) Tiger Team was 
formed to lead the technical effort, including:
• Evaluating current vehicle design susceptibility to roll control and tip over
• Reviewing methods for assessing occupant injury during ascent/aborts/ 
landings
• Developing an alternate seat/attenuation design solution which improves 
occupant protection and operability
• Testing the seat/attenuation system designs to ensure valid results
• The Occupant Protection Project was formed to develop, verify, 
validate and accredit biodynamics models using a variety of crash 
and injury databases that include NASCAR, Indy Car, and military 
aircraft. 
Page 3
NASA History of Landing Injury Risk
• The Brinkley Model is currently used by NASA and the 
military to determine the risk of injury to vehicle 
occupants based on seat acceleration
• The model calculates a Dynamic Response (DR) using a 
lumped mass modeled with a spring and damper attached 
to the seat
• An injury classification based on injury probability is then 
determined using pre-defined DR limits for each axis
• Very Low:  <0.05%
• Low:  0.05 - 0.5%
• Medium: 0.5 – 5%
• High: 5 – 50%
• Very High: >50%
• Disadvantages of the Brinkley Model
• The model assumes a basic seat geometry and so probability of 
injury is not reduced with seat or safety equipment improvements
• With the Brinkley model, the only way to reduce injury risk is to 
attenuate energy
• Brinkley model only predicts if an injury occurs
• Brinkley model does not predict injury severity, or anatomical 
location
Page 4
Modeling Road Map
Validate
Model 
with Sled 
Tests
Run Orion
Landing
Cases
NASCAR
IRL
Orion
Estimate
Total
Program
Risk
Estimate
P(inj) for each
Biodynamic
response
Run Injury
And 100-200
Non-Injury
Cases
Define
Transfer
Function
Estimate
Biodynamic
Responses
For all cases
Run Injury
And 100-200
Non-Injury
Cases
Define
Transfer
Function
Estimate
Biodynamic
Responses
For all cases
Define
Transfer
Function
Estimate
Biodynamic
Responses
For all cases
Iterate as hardware matures
Page 5
Relating Race Car Crash Data to Orion
• How do we relate NASCAR 
and Indy Racing League 
(IRL) crash data to Orion?
• Use numerical models with 
Hybrid-III manikin
• Use actual crash data to relate 
biodynamic responses to 
injuries
• Relate NASCAR / IRL 
biodynamic manikin responses 
to biodynamic manikin 
responses from CEV cases
Page 6
Biodynamic Response Example: Head Acceleration
• Peak Head Acc: 74.6G
• HIC: 470
• NASCAR Rear Impact Case (+X)
• 56.5 g Impact
• 63.2 mph ΔV
Page 7
0.5% risk 2% risk 5% risk
Parameter
(Deconditioned)
Small 
Female
50th% 
Male
Large 
Male
Small 
Female
50th% 
Male
Large 
Male
Small 
Female
50th% 
Male
Large 
Male
Head
Head Injury Criteria (HIC 15) 300 500 700
Peak Head Acceleration (g) 119 112 109 151 142 138 166 155 151
Neck
Peak Neck (cervical) flexion bending moment (Nm) 42 83 83 57 108 125 89 163 222
Peak Neck (cervical) lateral bending moment (Nm) 33 65 65 41 82 82 62 123 123
Peak Neck (cervical) extension bending moment 
(Nm)
15 34 42 27 49 67 28 56 75
Peak Neck (cervical) axial tension (N) 631 943 1138 1753 2781 3363 2161 3440 4326
Peak Neck (cervical) compression (N) 596 946 1142 1067 1694 2046 2167 3440 4154
Peak Neck (cervical) shear force (N) 593 946 1142 919 1462 1766 1680 2666 3219
Lumbar Lumbar resultant force TBD TBD TBD
Leg Peak Tibial Axial Compression 1914 3000 3690 2490 3900 4800 3825 6000 7380
Peak Femur Axial Compression 1914 3000 3690 2498 3801 5013 3862 5670 8100
Chest Chest Sternal to Spine Deflection (mm) 28 31 35 36 44 49 41 50 55
Definition of Biodynamic Responses
Per CxP 70024 (HSIR revC)
• Using military, passenger vehicle and race car published research and 
requirements, we worked with industry experts to identify biodynamic 
responses and determine the limits that would best protect the crew
Page 8
Relating Injury Risk
• Abbreviated Injury Scale (AIS) describes 
injuries anatomically
• Standardize injury terminology
• Rank injuries by severity
• Facilitate comparisons of injury studies
• Using an operationally relevant injury 
scale, we can classify AIS injury codes 
into several categories
• Using these injury severities and 
anatomical location, we can determine 
probability of injury occurrence and 
severity for each region of the body
Parameter-
Scale
Injury 
Magnitude
Self-
Egress 
Ability
Flight Status
1 No Injury No 
Impact
No delay 
in return
2 Minor 
Injury
Minor 
Impact
Short 
Delay in 
Return
3 Moderate 
Injury
Major 
Impact
Long 
Delay in 
Return
4 Severe 
Injury
Unable Ended/
DQ’d
Page 9
Head Injury
Injury
AIS Score
Operationally 
Relevant Injury 
Score
Mild Concussion 161001.1 2
Severe Concussion 161006.3 3
Skull Fracture 150000.2 4
Basilar Skull Fracture 150200.3 4
Laceration 110604.1 2
Biodynamic Response 
Parameters
HIC15
Head Acceleration
Head Movement
Upward Head Movement
Examples of potential Operationally-Relevant Injuries and associated 
Biodynamics Response Parameters
Page 10
NASCAR Injury Distribution
• 4261 Non-Injury Cases
• 16 Class I Injuries
• 15 Class II Injuries
• 4 Class III Injuries
Page 11
Estimate Results: Brinkley Scores
• Low (0.5%):
• P(inj) = 0.16%
• Medium (5%):
• P(inj) = 0.28%
• High (50%): 
• P(inj) = 0.44%
• Very High
• P(inj) = 5.0%
• Brinkley Model would predict 
~608 injuries vs. 32 observed
IRC No Injury
Class 
I
Class 
II
Class 
III
Class 
IV Total P(inj)
Low 2434 2 2 0 0 4 0.16%
Medium 707 1 1 0 0 2 0.28%
High 683 0 2 1 0 3 0.44%
Very 
High 437 13 7 3 0 23 5.0%
Page 12
Determining Risk of Injury
• Using the NASCAR data set, statistical modeling techniques will be 
employed to relate injury predictors (biodynamic responses) with 
the probability of injury by severity
• Once the each biodynamic response has an associated probability 
of injury, the Orion landing cases can be assessed to determine the 
probability of injury
• Using these data, a team of experts will systematically determine 
what risk is acceptable in an operationally relevant environment
• Using landing probabilities, the goal is to lower total risk over all 
landing conditions
0
.0
1
.0
2
.0
3
.0
4
.0
5
P
0 20 40 60 80 100
X
lower 95% conf upper 95% conf point est
Probability of injury (P) for given injury response (X)
Page 13Operations Integration All Hands - 11/12/2007
Backup Slides
Page 14
Occupant Protection Project Charter
TASK DESCRIPTION:
Determine appropriate methods for modeling and prediction of potential crew injuries.  Activities include conducting 
data mining of injury databases (NASACAR, CIREN, military, etc); assessment of impact simulation and injury 
prediction methodologies.  Recommend techniques / changes to requirements appropriate for Orion including 
stated limitations.
Data Mining of Injury Databases 
Review automobile, NASCAR, military, and other applicable occupant injury databases
Review limitations and capabilities of analysis tools/techniques
Review impact simulation techniques appropriate for Orion
Review occupant injury prediction techniques
Recommend analysis techniques and models appropriate for use by Orion 
Recommend appropriate human mass properties data for use by Orion
Provide the necessary mass properties data
Recommend appropriate impact acceleration/occupant injury criteria 
Given driving load cases, assess current 606C baseline and alternate designs and recommend potential 
modifications, if required
PRODUCTS
Periodic Briefings to Steering Committee/CEV Project Office
Given driving load cases (from Orion Project Office)
Analyze Orion baseline design (606C) as well as alternate configurations developed by Task #2 team
Final report to include:
Recommendations for standard analysis techniques and models
Recommendations for impact acceleration/occupant injury criteria appropriate for use by Orion
Page 15Operations Integration All Hands - 11/12/2007
Occupant Protection Modeling Forward Plan
Start with 
Baseline HSIR 
requirements
Use evolving 
Biodynamics model  
to define 
restraint/attenuation
Model Verification Test Series
Model Development, Verification, Validations and Accreditation
Definition of Acceptable Risk
Design, Development and Verification of seat/restraint/attenuation system
Define 
operationally 
relevant injury 
scale
Define medical and 
operational drivers 
and mission 
success criteria
Reclassify &  pool 
injury data into 
operationally 
relevant injury 
scale
Definition of medical  
Injury disposition policy
(Bound long-term 
health risk)
Define highest 
level of injury risk 
consistent with 
successful 
Program
Reduce injury risk 
based on other 
medical, operational 
and ethical 
considerations
Monte Carlo 
simulation of 
landing case 
probabilities
Develop 
Consensus 
Recommendations 
for acceptable 
injury risk vs 
landing probability 
distributions
Refine Seat 
/restraint/stroking 
design
Determine the axis 
and degree of 
stroke required
Determine design 
tolerance failure 
cases (stacked 
failures)
Feed seat/restraint 
attenuation models 
into Biodynamics 
model 
Integrated Test Plan
Definition of 
appropriate  
injury response 
parameters
Pool crash 
injury data and 
classify in an 
operationally 
relevant 
classifications
Perform logistic 
regression  
between injury 
response  
parameters and 
injury outcome in 
pooled database
Model 
Development
Define Validation criteria
Validate Model
Definition of 
acceptable 
injury criteria
Iterate until we meet 
acceptable injury 
criteria
Model 
Verification
Hardware Test Series (Contractor/Program)
Suit-Ring Occupant Interactions Test Series with THUMS Model support


Occupant Protection during Orion Crew Exploration Vehicle Landings

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