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Entry, Descent, and Landing
Systems Short Course
Subject:
Author:
CPAS Parachute Testing, Model
Development, & Verification
Leah M. Romero
JETS/Aerodyne, LLC
sponsored by
International Planetary Probe Workshop 10
June 15-16, 2013
San Jose, California
Agenda
•
•
•
•
•
•
CPAS Overview
Airdrop Testing
Parachute Test Analysis
Development of a Parachute Model
System Verification & Validation
Future of CPAS
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
2
CPAS OVERVIEW
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
3
CPAS Overview
• Capsule Parachute Assembly System (CPAS) is the
human rated parachute system for the Orion vehicle
used during re-entry
– Similar to Apollo parachute design
– Human rating requires additional system redundancy
• A Government Furnished
Equipment (GFE) project
responsible for:
–
–
–
–
–
–
Design
Development testing
Performance modeling
Fabrication
Qualification
Delivery
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
4
CPAS Concept of Operations
Blunt End Forward
Launch Abort
System Jettison
Mortar
Deployed
Mortar
Deployed
1st Stage
FBCPs
Mortar
Deployed
Mortar
Deployed
Forward
Bay
Cover
Pilots
2nd Stage
Full
Open
Mortar
Deployed
Low Altitude and Pad
Abort Sequence
(direct to mains)
Pilot
Deployed
1st Stage
2nd Stage
Full Open
Main
Pilots
Pilot
Deployed
1st Stage
2nd Stage
Full Open
Drogues
Mains
Pilots
Nominal Mission and
High Altitude Abort
Deployment Sequence
June 15-16, 2013
Mains
International Planetary Probe Workshop 10
Short Course 2013
5
CPAS Requirements
• The CPAS Project Technical Requirement Specification
(PTRS) levies requirements on the system
• To verify the design and validate the requirements
– Some system aspects are modeled
– Some rely on demonstration
• 155 requirements total with 104 completely or partially
verified by analysis
• Verification and Validation Document (V&VD)
– Contains success criteria for verification of each requirement
– Identifies the method and pass/fail criteria
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
6
CPAS Analysis Focus
• CPAS analysis team responsible for verification and validation of 23
requirements
– Functional and performance
• Meet all other requirements when in deployment envelope
• Meet all other requirements with specified vehicle mass
– Rate of Descent (ROD)
• Crew and vehicle structure safety
– Parachute Loads – single riser and cluster loads
• Individual parachute failure
• Vehicle structural failure
– Rotation Torque and Flyout Angle Limit
• Main risers induce rotation
• Orient vehicle edge into water for landing
• Develop models anchored to flight tests
• Conduct Monte Carlo analyses to examine possible failure
conditions and compare results to requirements
– Parachute canopy or riser failure
– Failure to deploy
– Parachute flagging or skipped stage
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
7
AIRDROP TESTING
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
8
CPAS Parachutes
•
Forward Bay Cover Parachutes (FBCPs) (~7 ft)
FBCP
– Pulls off Forward Bay Cover (FBC) from vehicle.
•
Drogue Parachutes (~23 ft)
– Stabilizes the vehicle for Main deployment.
•
Pilot Parachutes (~10 ft)
Drogue Chute
– Pulls out the Main chutes.
•
Main Parachutes (~116 ft)
– Slow the vehicle to landing.
•
Pilot Chute
Test Support Parachutes
Main Chute
– Extraction Chutes (~28 ft)
• Pulls the vehicle out of the aircraft. Used for testing only.
– Programmer Parachutes
• Used to create the proper test conditions for the Drogue, Pilot, or
Main chutes. Used for testing only.
• Can sometimes be an identical chute as the Drogues, but the
use is different.
Extraction Chute
Programmer Chute
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
9
Engineering Development Unit
(EDU) Test Vehicles
•
Mid-Air Delivery System (MDS) & Cradle Platform Separation System (CPSS)
–
•
Allows the PCDTV and PTV to be deployed from an aircraft cargo bay
Parachute Compartment Drop Test Vehicle (PCDTV)
– Tests the full CPAS system utilizing an aerodynamically stable vehicle
– Dart shape based on the Solid Rocket Booster and Ares booster parachute test
program
• Allows for achievement of high dynamic pressure
•
Parachute Test Vehicle (PTV)
– Tests the full CPAS system with representative flight like wake environment
– Unable to achieve nominal entry environment with current test techniques
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
10
PCDTV/MDS Test Sequence
Extraction from a C130 at 25,000 ft MSL
Separation
Drogues
Deploy
One reefed Gen II Drogue
as Programmer Deploy
Pilot
Deploy
Mains
Full
Open
Mains 2nd Stage
June 15-16, 2013
Main 1st Stage
International Planetary Probe Workshop 10
Short Course 2013
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PTV/CPSS Test Sequence
Extraction from C-17 at
25,000 ft with two 28 ft
Extraction Parachutes
Smart Separation
after Ramp Clear
Two full-open Gen II Drogues
as Programmers deployed
Programmer cut
One Drogue
deployed
Programmers
Inflated
Drogue
Inflated
PTV
Touchdown
June 15-16, 2013
3 Pilots lift 3
Mains with
nominal
reefing
Smart Drogue
Release using SDR
International Planetary Probe Workshop 10
Short Course 2013
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Video
• For more videos, search for NASACPAS
user on YouTube
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
13
PARACHUTE TEST ANALYSIS
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
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Parachute Analysis: Preflight
• No single end-to-end
simulation available
therefore multiple
simulations used to
model different phases
• Define test objectives:
number and configuration
of programmers
• Assesses risk of test through Monte Carlos:
loads, altitude, range safety, etc.
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
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Parachute Analysis: Post-flight
Qbar (psf)
60
50
Circular
Sector
Ring 4
Sail 1
40
PTV Touchdown
Main steady-state
Drogue Release
70
Drogue S/N 6 Disreef to Full
80
Programmers Release
90
Separation
• Reduce and plot test data against prediction
• Photogrammetric analysis used to
characterize parachute behavior
rRing
30
Aircraft Tray SPAN-SE
SPAN-SE Raw IMU
Best Estimate Trajectory (GPS/IMU)
DSS Preflight (12/11/2012)
20
10
0
0
50
100
150
Time (s - RC)
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
16
DEVELOPMENT OF A
PARACHUTE MODEL
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
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Parachute Modeling
• Parachute parameters
– Drag area: CDS
– Fill constant: n
– Opening profile shape
exponent: expopen
– Overinflation factor: Ck
– Ramp down time: tk
100
(CDS)peak
90
80
(CDS)i
Drag Area, CDS
tfp
70
Drag Area (sq ft)
60
Drag Area, CDS
expopen = 0.5
tk
50
40
expopen = 1.5
30
expopen = 1
expopen < 1
expopen > 1
Time, t
June 15-16, 2013
20
tf
10
(CDS)i-1
0
0.0
ti
International Planetary Probe Workshop 10
Short Course 2013
0.1
Time, t
Time (sec)
0.2
0.3
18
Model Development
• Determine appropriate parachute parameter
through test data reconstructions
– Run simulations varying parachute parameters until
test data is matched
– Can be subjective
• Do this for each test, parachute type, and stage
CDT-3-4
Drogue A
CDT-3-5
Drogue B Drogue A Drogue B
CDT-3-6
Drogue A Drogue B
Clean Reefed Drag Area per canopy, (CDS)R (ft2)
128
128
146
158
133
134
Over-inflation Factor, Ck
1.2
1.3
1.2
1.3
1.3
1.4
Fill Constant, n
3.4
6.9
5.4
4.9
7.5
5.2
Opening profile shape exponent, expopen
0.90
2.1
2.1
2.2
2.8
1.9
Ramp down time, tk (s)
0.69
0.13
0.03
0.06
0.14
0.11
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
19
Model Development
• Generate dispersions for each parachute type and stage
• Dispersion bounding: caps or polygon
TMIN(1-EF)
TMAX1+EF)
Bounds
4
(formerly uniform
dispersions)
3
Test Data
Best Fit of Test Data
Median: 2.35
Mean: 2.79
Test Data
Bounds: 0.90063
6.7474
logn:
0.14547
0.21556
Bounds: 0.76275
1.8689
Median: 1.17
-1
2.5
2
+1
3
2.5
2
-2
1.5
1.5
1
1
-3
0.5
0
+2
0
+3
1
2
3
4
5
6
7
8
9
0.5
10
Canopy Fill Constant, n
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
0
2
4
6
8
0
10
EDU Main Stage 3 n
20
EDU Main Stage 3 expopen
3.5
Frequency
Test Data
logn: 0.9209
0.44781
Bounds: 0.90063
6.7474
Median: 2.41
Model Development
• Redraw
dispersions until
inside polygon
• Deliver
parachute
model: 200K
dispersions via
21 text files
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
Points within boundary are
retained; outside points
(green) are re-drawn until
acceptable (circled red)
21
SYSTEM VERIFICATION &
VALIDATION
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
22
System V&V Introduction
• CPAS must meet its requirements to ensure the
system functions as intended, individually and with
other Orion systems
• V&V plan is a “list of activities that establishes the
compliance” with the requirements
• Analysis team requirements are verified via analysis
• Instructions provided through NASA Standard 7009
“Standard for Models and Simulations”
– Model must be credible
• Determine through Model Credibility Scoring Guidelines
• Completed for each model and simulation
– Current primary simulation: Decelerator System Simulation (DSS)
– Future primary simulation: Flight Analysis & Simulation Tool (FAST)
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
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Model Credibility Score for DSS (January 2011)
Level
Verification
Validation
Input
Pedigree
Results
Results
Uncertainty Robustness
Use History
Sensitivity
Input data agree Non-deterministic known for most
with real-world & numerical
parameters; key
data.
analysis.
sensitivities
identified.
De facto
standard.
M&S
People
Management Qualifications
Extensive
experience in and
use of
recommended
practices for this
particular M&S.
4
Numerical error
small for all
important
features.
3
Results agree
with
Formal numerical experiemental
error estimation. data for
problems of
interest.
Input data agree
with
Sensitivity
experiemental Non-Deterministic
known for many
data for
analysis.
parameters.
problems of
interest.
Advanced degree
Previous
or extensive M&S
predictions were
experience, and
Predictable process.
later validated
recommended
by mission data.
practice
knowledge.
2
Results agree
with
Unit and
experiemental
regression testing
data or other
of key features.
M&S on unit
problems.
Input data
Deterministic
Sensitivity
traceable to
analysis or expert known for a few
formal
opinion.
parameters.
documenation.
Formal M&S
training and
Used before for
Established process. experience, and
critical decisions.
recommended
practice training.
1
Conceptual and
mathematical
models verified.
Conceptual and
mathematical
models agree
with simple
referents.
Input data
traceable to
Qualitative
informal
estimaes.
documenation.
Qualitative
estimates.
Passes simple
tests.
Managed process.
Engineering or
science degree.
0
Insufficient
evidence.
Insufficient
evidence.
Insufficient
evidence.
Insufficient
evidence.
Insufficient
evidence.
Insufficient
evidence.
Insufficient
evidence.
Results agree
with real-world
data.
M&S Development
June 15-16, 2013
Insufficient
evidence.
M&S Operations
International Planetary Probe Workshop 10
Short Course 2013
Continual process
improvement.
Supporting Evidence
24
CPAS V&V Cycle
1)
2)
3)
4)
5)
Design the parachute subsystem
Test the design through flight and ground tests
Development and Qualification test data is gathered
Document the test data and advancements in parachute physics knowledge
Verify the parachute subsystem meets flight performance requirements
a)
b)
6)
7)
8)
If No, update the document for requirement clarification
If No, update the design so that it can meet the requirement
Validate flight performance requirements at the integrated Crew Module level
Conduct integrated flight tests
Run-for-the-record simulations
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
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FUTURE OF CPAS
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
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Future of CPAS
• Development Testing
– EDU (plan as of May 20, 2013)
• 2013 (remaining): 2 tests – 1 PTV,
1 PCDTV
• 2014: 4 PTV tests
• 2015: 2 PTV tests
– EFT-1 in fall 2014
• Qualification Tests
• Simulation & model development
•
•
•
Lockheed Martin’s MPCV
Transition to end-to-end simulation in an independent parachute model
Refinement of statistically derived dispersions
Determine and document Model Credibility of simulation used for run-forthe-record V&V
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
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SPECIAL THANKS
CPAS Analysis Team
Pat Galvin
Johnny Blaschak
Kristin Bledsoe
John Davidson
Megan Englert
Usbaldo Fraire
Fernando Galaviz
Eric Ray
Joe Varela
June 15-16, 2013
Koki Machin
Entire CPAS team
International Planetary Probe Workshop 10
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For More Information…
•
2009 AIAA ADS Conference
–
–
•
Overview of the Crew Exploration Vehicle Parachute Assembly System (CPAS) Generation I Drogue and Pilot
Development Test Results, R. Olmstead
Overview of the Crew Exploration Vehicle Parachute Assembly System (CPAS) Generation I Main and Cluster
Development Test Results, K. Bledsoe
2011 AIAA ADS Conference
–
–
–
–
–
–
–
–
–
–
–
–
–
Proposed Framework for Determining Added Mass of Orion Drogue Parachutes, U. Fraire
Summary of CPAS Gen II Testing Analysis Results, A. Morris
Load Asymmetry Observed During Orion Main Parachute Inflation, A. Morris
Challenges of CPAS Flight Testing, E. Ray
Verification and Validation of Requirements on the CEV Parachute Assembly System Using Design of Experiments, P.
Schulte
Development of Monte Carlo Capability for Orion Parachute Simulations, J. Moore
Photogrammetric Analysis of CPAS Main Parachutes, E. Ray
A Hybrid Parachute Simulation Environment for the Orion Parachute Development Project, J. Moore
Measurement of CPAS Main Parachute Rate of Descent, E. Ray
Development of the Sasquatch Drop Test Footprint Tool, K. Bledsoe
Development of a Smart Release Algorithm for Mid-Air Separation of Parachute Test Articles, J. Moore
Simulating New Drop Test Vehicles and Test Techniques for the Orion CEV Parachute Assembly System, A. Morris
Verification and Validation of Flight Performance Requirements for Human Crewed Spacecraft Parachute Recovery
Systems, A. Morris
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
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For Even More Information…
•
2013 AIAA ADS Conference
–
–
–
–
–
–
–
–
–
–
Extraction and Separation Modeling of Orion Test Vehicles with ADAMS Simulation, U. Fraire
An Airborne Parachute Compartment Test Bed for the Orion Parachute Test Program, J. Moore
Application of a Smart Parachute Release Algorithm to the CPAS Test Architecture, K. Bledsoe
Application of Statistically Derived CPAS Parachute Parameters, L. Romero
A Boilerplate Capsule Test Technique for the Orion Parachute Test Program, J. Moore
Testing Small CPAS Parachutes Using HIVAS, E. Ray
Improved CPAS Photogrammetric Capabilities for Engineering Development Unit (EDU) Testing, E. Ray
Reefing Line Tension in CPAS Main Parachute Clusters, E. Ray
Skipped Stage Modeling and Testing of the Capsule Parachute Assembly System, J. Varela
Reconstruction of Orion EDU Parachute Inflation Loads, E. Ray
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
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QUESTIONS?
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
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BACKUP
June 15-16, 2013
International Planetary Probe Workshop 10
Short Course 2013
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