22 March 20071 MSL Entry, Descent, and Landing Instrumentation (MEDLI) Programmatic Review Neil...
-
Upload
keyla-polit -
Category
Documents
-
view
219 -
download
0
Transcript of 22 March 20071 MSL Entry, Descent, and Landing Instrumentation (MEDLI) Programmatic Review Neil...
22 March 2007 1
MSL Entry, Descent, and Landing
Instrumentation (MEDLI)
Programmatic ReviewNeil Cheatwood, Principal Investigator
Mike Wright, Deputy Principal Investigator
Alan Little, Project Manager
Mike Gazarik, Deputy Project Manager
Helen Hwang, Deputy Project Manager
Jeff Herath, Chief Engineer
22 March 2007
22 March 2007 2
Project Formulation Overview
22 March 2007 3
MEDLI Rationale
• MSL is taxing the limits of current modeling capabilities for Mars entry missions
Aeroheating uncertainties are greater than 50% on heatshield, due to early transition to turbulence, surface chemistry, and ablation induced roughness.
• A primary source of uncertainty is a lack of relevant flight data for improved model validation
A small amount of TPS data was obtained from Pathfinder, but no direct measurements of aeroheating, aerodynamics, or atmosphere.
• MEDLI instrumentation suite will collect an order of magnitude more EDL data than all previous Mars missions
– Thermocouple and recession sensor data will define aeroheating uncertainties and reduce TPS risk for future missions, and will determine performance limits of heritage materials.
– Pressure data will permit accurate trajectory reconstruction, separation of aerodynamic and atmospheric uncertainties in the hypersonic and supersonic regimes.
– MEDLI flight data is relevant to Orion since its Block-I backup TPS options include the same material (SLA-561V), in a similar heating/shear stress environment, as MSL.
22 March 2007 4
Project Initiation
• Entry, Descent, and Landing (EDL) instrumentation study conducted by NASA EDL team in July 2006
• Constraint set provided in August 2006 by SMD/Mars Exploration Program & MSL Project to minimize/control risk, and provide a basis for analyses
• “Formalized” into Flight Project in September 2006 with LaRC as Project Manager, ARC as Deputy Project Manager
• Baseline architecture briefed to ARMD/ESMD/SMD October 5th, 2006
– Excellent progress led to authorization to investigate enhanced option
• Final architecture briefed to Science, Exploration, and Aeronautics Directorate AA’s on October 25th, 2006
– Authority to proceed given with implementation guidelines/constraints and a final decision gate
• Final Authority to Proceed given at the Agency Program Management Council Meeting on November 2nd, 2006
22 March 2007 5
System Overview
MEDLI Chief Engineer
Jeff Herath (LaRC)
22 March 2007 6
Description & Top Level Technical Objective
MEDLI is an instrumentation suite installed in the heatshield of the Mars Science Laboratory’s (MSL) Entry Vehicle that will gather data on the atmosphere and on aerothermal, Thermal Protection System (TPS) and aerodynamic characteristics of the MSL Entry Vehicle during entry and descent providing engineering data for future Mars missions.
Thermocouples
Recession Sensors
Pressure Sensors
22 March 2007 7
MEDLI Active: Atmospheric Interface t-10min
MEDLI Operations Concept During MSL EDL
MEDLI Inactive: Atmospheric Interface t+4min
MSL EDL Outline
MEDLI Data Transmitted
MEDLI is taking data and MSL is storing the data in the Rover for transmission after landing
22 March 2007 8
MEDLI System Description
• MEDLI consists of 7 pressure ports and 7 integrated sensor plugs (containing four thermocouples and a recession sensor) all installed in the forebody heatshield of the MSL entry vehicle.
• These sensors are wired to a Sensor Support Electronics (SSE) box, that provides power to the sensors and conditions and digitizes the sensor signals, which are sent to MSL’s Descent Stage Power and Analog Module (DPAM) and are then sent to the Rover Compute Elements over the MSL EDL-1553 bus for storage until the data is telemetered back to Earth after landing.
Cruise Stage
Backshell
Descent Stage
Rover
Heatshield
Cruise Stage
Backshell
Descent Stage
Rover
Heatshield
MSL (For Reference)
Sensor SupportElectronics
DPAM
Rover
Descent Stage
Heatshield
Backshell
cutter
Power
cutter
cutter
1553 Bus
RS422 Serial
RCE-B
28v Power
Heatshield Sensors
RCE-A
RS422 Serial
22 March 2007 9
Hollow kapton tube
Wound resistive wire
Outer kapton layer (tube or coating)
MEDLI Consists of Three Main Subsystems
• MEDLI Instrumented Sensor Plug (MISP)
– A plug consists of 1.3” diameter heatshield Thermal Protection System (TPS) core with embedded thermocouples and recession sensors
– Each plug consists of 1 recession sensor and 4 thermocouple sensors
• Mars Entry Atmospheric Data System (MEADS)
– Series of through-holes, or ports, in TPS that connect via tubing to pressure transducers
• Sensor Support Electronics (SSE)
– Electronics box that conditions sensor signals and provides power to MISP and MEADS
Thermocouple Plug Recession Sensor
Mars Entry Atmospheric Data System
Sensor Support Electronics
22 March 2007 10
MEDLI on Heatshield w/ Backshell & Rover
SSEMISP (1 of 7 Plugs) MEADS (1 of 7 Ports)
Rover
22 March 2007 11
Science Objectives
22 March 2007 12
MEDLI Top Level Flight Science Objectives
Overview
MEDLI is an instrumentation suite to be installed in the heatshield of the Mars Science Laboratory’s (MSL) Entry Vehicle that will gather data on its aerothermal, aerodynamic, and thermal protection system (TPS) performance, as well as atmospheric density and winds, during entry and descent, and will provide engineering data for all future Mars missions.
Aerodynamics & Atmospheric
– Determine density profile over large horizontal distance
– Determine wind component – Separate aero from atmosphere– Confirm aero at high angles of attack
Aerothermal & TPS– Verify transition to turbulence– Determine turbulent heating levels– Determine recession rates and subsurface
material response of ablative heatshield at Mars conditions
22 March 2007 13
Aerothermal/TPS Objectives
Aerodynamics/Atmosphere Objectives
P1 P2 P3 P4 P5 P6 P7371 Basic Surface Pressure X X X X X X X
372 Angle of Attack X X X X X
373 Angle of Sideslip X X X
374 Dynamic Pressure X X
375 Mach Number X X
LocationReq ID Technical Objectives
MEDLI Measurements:Sensor Placement Strategy
T1 T2 T3 T4 T5 T6 T7363a Basic Aeroheating X X X X X X X
363b Stagnation Point Heating X X
364 Turbulent Leeside Heating X X X X X
365 TPS Recession Rate X X X X X X
366 Windside Heating Augmentation X X
367 TPS Total Recession X X X X X X
368 Subsurface Material Response X X X X X X X
369 Turbulent Transition X X X X
Req ID
LocationTechnical Objectives
22 March 2007 14
MEDLI Objectives: Aerothermal
• Basic and Stagnation Region Aeroheating (PS-363)– Justification
Re-creation of heating distribution increases confidence in aerothermal predictive tools.
– Implementation
All seven plugs are located to enable profile reconstruction (including stagnation point, streamline tracing, asymmetry).
• Turbulence and Transition (PS-364, PS-366 & PS-369)
– JustificationTransition on leeside predicted prior to peak heating. Predicted turbulent heating more
than a factor of two higher than maximum laminar heating, and uncertainty is higher.
– Implementation• Five of the seven plugs located to detect peak heating levels, profile, and transition time.• Two plugs located to detect possible windside transition.
Engineering Impact• First in-situ model validation of flight aeroheating tools will lead to better uncertainty
quantification and margin clarity for future Mars entry missions.
• Validation of turbulent heating predictions will reduce the uncertainty that drives large vehicle TPS sizing.
22 March 2007 15
MEDLI Objectives: TPS
• Recession Rate and Integrated Total (PS-365 & PS-367)
– Justification:
This is the primary remaining TPS response uncertainty for Mars entries (SLA-561V).
– Implementation:
• HEAT isotherm sensors track an isotherm through the material as a function of time.
• Recession reconstructed via calibration and analysis.
• Subsurface Material Response (PS-368)
– Justification:
TPS thermal response model is developed and validated with arc jet testing in air. Improved model validation requires in-situ data in Mars atmosphere.
– Implementation:
Thermocouples and HEAT sensor data will be compared to theoretical predictions of in-depth temperature response.
Engineering Impact• First in-situ validation of TPS response in Mars atmosphere.
• Reduction of TPS design margins and expansion of performance envelope for future Mars entry missions.
22 March 2007 16
MEDLI Objectives: Atmosphere and Aero
• Basic Surface Pressure (PS-371)– Justification:
Recreation of surface pressure distribution increases confidence in computational tools.
– Implementation:
Pressure ports are located to enable reconstruction of pressure distribution.
Engineering Impact:First in-situ model validation of flight aero tools will lead to better uncertainty quantification and
margin clarity for future Mars entry missions.
windside leeside
A A
22 March 2007 17
MEDLI Objectives: Atmosphere and Aero (cont)
• Dynamic Pressure and Mach Number (PS-374 & PS-375)
– Justification:
Uncertainties in atmospheric density are co-mingled with uncertainties in aero.
– Implementation:
Two of the seven pressure ports in the stagnation region.
• Angle of Attack and Angle of Sideslip (PS-372 & PS-373)
– Justification:
For a given density, accurate measurement of angle of attack and sideslip will allow comparison between predicted and realized aerodynamics.
– Implementation:
Five of the seven pressure ports centered about the cone apex.
Engineering Impact• Atmospheric density quantification for assessment of aerodynamics uncertainties.• Identification of wind component within vehicle performance (a la MER).
22 March 2007 18
Technical Status
22 March 2007 19
MEDLI - MSL Interface Overview
+28V Pwr
Pressure Transducer4 Thermocouples
per plugMISP: X7
Sensor Support Electronics
Descent Stage
Heatshield
DPAM-B
BS/HS CUTTER (NEW)
DS/BS CUTTER
Backshell
4 wire Serial Bus interface
Pwr
Signal
ConditioningSignalConditioning
RecessionSensor
MUX
MEADS: X7
REU Telemetry Bus
Comm
22 March 2007 20
MEDLI Subsystem Designs
• MEADS Design
22 March 2007 21
MEDLI Subsystem Designs (Continued)
• MISP Design
22 March 2007 22
MEDLI Subsystem Designs (Continued)
• SSE Design Top Removed for Clarity
2 Electronics Boards 305mm x 159mm (12” x 6.25”)
6x Inserts TPS
6x #10 Fasteners
6x Standoffs
Aluminum Honeycomb Core
Composite facesheet
Enclosure 337mm x 248mm (13.25” x 9.75”)
22 March 2007 23
Changes to Baseline MSL Accommodation
• Analog to Digital Interface Change
– Benefits both MSL and MEDLI
• Reduced Aeroshell Mass Impact
• Higher quality data (better signal to noise)
• Mass Allocation Shift
– Needed to accommodate additional SSE functions to support digital interface
– Original: (15 kg Total)
• 5 kg aeroshell mass impact
• 10 kg on heatshield, offset by removing ballast mass
– New: (15 kg Total)
• 2.5 kg aeroshell mass impact
• 12.5 kg on heatshield, offset by removing ballast mass
Cruise Stage
Backshell
Descent Stage
Rover
Heatshield
Cruise Stage
Backshell
Descent Stage
Rover
Heatshield
MSL (For Reference)
New Mass Allocation:
2.5 kg
12.5 kg
22 March 2007 24
MSL to MEDLI Resource Allocation Status
Resource Limit CBE Margin
Heatshield Mass (Kg) 12.5 9.93 26%
Backshell and Descent Stage Mass (Kg) 2.5 1.79 40%
Power (EDL Phase) (W) 30 14 114%
Data (MB) 1.5 1.13 32%
22 March 2007 25
MEDLI Technical Milestones
• Summary of Technical Milestones
– SRR Completed
– Level 2 Requirements Baselined & Level 4 Requirements in signature process
– Arc Jet Tests for MEADS development
• Phase I Completed, Phase II in Progress
– Interface Development
• ICD TIM Completed
• Analog/Digital Trade Study Completed: Digital Selected
• Mechanical and Thermal Draft ICD (3/2007)
– Transducer Procurement (3/2007), Delivery (10/2007)
– SSE Engineering Unit Delivery (5/2007)
– SLA and Coupon Delivery (8/2007)
– Environmental Qualification (12/2007)
– Flight System Delivery (4/2008)
Be
fore
Te
st
Aft
er
Te
st
Clo
se
Up
MEADS Arc Jet Testing
22 March 2007 26
MEDLI Project Organization
Exploration System Mission DirectorateJeff Volosin (HQ)
Principal InvestigatorPI: Neil Cheatwood (LaRC)
Deputy PI: Mike Wright (ARC)
Project ManagementPM: Alan Little (LaRC)
DPM: Helen Hwang (ARC)DPM: Mike Gazarik (LaRC)
CE: Jeff Herath (LaRC)Schedule: Cameron Pyle (LaRC)Resources: Kathy Ferrare (LaRC)
MEADS/SSE SubsystemFrank Novak (LaRC)
Mission OperationsJeff Herath (LaRC)
MISP SubsystemSteve Kihara (ARC)
Ground SystemsJohnny Fu (ARC)
Environmental TestRick Jones (LaRC)
MSL Project OfficeMission Manager
Mike Watkins (JPL)
MSL Flight System AccomodationArbi Karapetian (JPL)
MSL AeroshellChristine Szalai (JPL)Pam Hoffman (JPL)
Tony Agajanian (JPL)Eric Slimko (JPL)Rich Hund (LM)
QualificationEd Martinez (ARC)
Safety & Mission AssuranceRay Heineman (LaRC)Robert Burney (ARC)
Science Team Co-IsAerothermal: Mike Wright (ARC)
TPS: Bernie Laub (ARC)Aerodynamics: Walt Engelund (LaRC)
GNC: Chris Cerimele (JSC)
MSL Project ManagerRichard Cook (JPL)
Mars Program ManagerFuk Li (JPL)
Science Mission DirectorateDoug McCuistion (HQ)
Mark Dahl (HQ)Michael Myers (HQ)
Safety & Mission Assurance Cindi Kingery (JPL)Howard Tucker (LM)