Presentation on theme: "22 March 20071 MSL Entry, Descent, and Landing Instrumentation (MEDLI) Programmatic Review Neil Cheatwood, Principal Investigator Mike Wright, Deputy Principal."— Presentation transcript:
22 March 20071 MSL Entry, Descent, and Landing Instrumentation (MEDLI) Programmatic Review Neil 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 20073 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 20074 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 5 th, 2006 –Excellent progress led to authorization to investigate enhanced option Final architecture briefed to Science, Exploration, and Aeronautics Directorate AA’s on October 25 th, 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 2 nd, 2006
22 March 20075 System Overview MEDLI Chief Engineer Jeff Herath (LaRC)
22 March 20076 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 20077 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 20078 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. MSL (For Reference)
22 March 20079 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 200710 MEDLI on Heatshield w/ Backshell & Rover SSE MISP (1 of 7 Plugs) MEADS (1 of 7 Ports) Rover
22 March 200712 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 200714 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) –Justification Transition 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 200715 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 200716 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. windsideleeside A A
22 March 200717 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 200719 MEDLI - MSL Interface Overview +28V Pwr Pressure Transducer 4 Thermocouples per plug MISP: X7 Sensor Support Electronics Descent Stage Heatshield DPAM-B BS/HS CUTTER (NEW) DS/BS CUTTER Backshell 4 wire Serial Bus interface Pwr Signal Conditioning Recession Sensor MUX MEADS: X7 REU Telemetry Bus Comm
22 March 200720 MEDLI Subsystem Designs MEADS Design
22 March 200721 MEDLI Subsystem Designs (Continued) MISP Design
22 March 200722 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 200723 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 MSL (For Reference) New Mass Allocation: 2.5 kg 12.5 kg
22 March 200724 MSL to MEDLI Resource Allocation Status ResourceLimitCBEMargin Heatshield Mass (Kg)12.59.9326% Backshell and Descent Stage Mass (Kg)2.51.7940% Power (EDL Phase) (W)3014114% Data (MB)1.51.1332%
22 March 200725 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) Before Test After Test Close Up MEADS Arc Jet Testing