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www.sea.co.uka Cohort plc company RF Wireless in Planetary Exploration and AIV E W Pritchard Systems Engineering & Assessment Ltd
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www.sea.co.uka Cohort plc company Wireless Application Areas Low Power Wireless Sensors Robust Networking EMC Analyses Structured (spacecraft) demonstrator Planetary demonstrator Flight demonstrator? CAN-BT Bridge & demo SpW-WiFi Bridge & demo Wireless Test Port EMC Analyses
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www.sea.co.uka Cohort plc company RF Wireless Outline Schedule AprMayJunJulAugSepOctNovDecJanFebMarAprMayJunJulAugSepOctNovDecJanFeb Jul 08 LPPNS Concept Review EGSE/AIT Requirements & Preliminary Design EGSE/AIT Design Dec 08 LPPNS PDR EGSE/AIT CDR Oct 08 EGSE/AIT PDR LPPNS Building Blocks, Requirements & Preliminary Design Application Use Cases Demonstration Test Environment Mar 09 LPPNS CDR LPPNS Design EGSE/AIT Procure/Build Apr 09 EGSE/AIT TRR Oct 09 EGSE/AIT AR LPPNS Demonstrator Development and Build Sep 09 LPPNS TRR Demonstrator Tests Dec 09 LPPNS TRB EGSE/AIT Test and Demonstration 20092010 Today
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www.sea.co.uka Cohort plc company Planetary Wireless The main purpose of wireless arrays in a planetary context is to extend the data gathering footprint This can be done using Rovers but they are transient devices providing a snapshot of different locations Some aspects of planetary investigations require long-term monitoring of separated locations for example: –Seismology –Meteorology and Climatology It can be said that static systems benefit from dynamic monitoring but dynamic systems require long-term static monitoring
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www.sea.co.uka Cohort plc company Seismology Seismology can be separated into deep and shallow investigations Deep seismology is the mapping of the gross structure of the planet, core, mantle, asthenosphere (if any) and lithosphere, and uses arrays with large separation. Arrays with close separation can be used to image fine shallow structure This is important for Mars in terms of determining possible sedimentary structures In a lunar context the volume of flood deposits in the mare can be assessed In any planetary scenario it is also important for shallow igneous structures such as plutons and magma chambers.
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www.sea.co.uka Cohort plc company Seismic Wireless Arrays The point in seismic arrays is timing – on wired arrays we know how long it takes a pulse to go down a wire For large arrays on Earth we can keep to wires and tow them This is not an option on other planets where the seismic sources tend to be ad hoc (impacts, quakes) For extra-terrestrial arrays wireless has definite advantages but we must consider timing and time- tagging of data. Data rates are low long-term but high short term.
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www.sea.co.uka Cohort plc company Possible Seismometer
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www.sea.co.uka Cohort plc company Other Possible Uses Pressure / temperature / light sensors for microclimate (e.g. Martian dust devils) Chemical detectors to monitor atmospheric diffusion Relays and localisation of mini-rovers Route markers in cave systems
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www.sea.co.uka Cohort plc company Issues in Planetary Wireless Propagation is largely line of sight and horizon limited Horizon distance:- –Earth radius 6371km, tangent height to 4km 1.26m –Mars radius 3386km, tangent height to 4km 2.36m –Moon radius 1737km, tangent height to 4km 4.6m –Europa radius 1560km, tangent height to 4km 5.1m On Earth, the radio horizon is extended by atmospheric refraction and ionospheric reflection. This would not be the case on Moon, Mars. On Earth, GPS is available for localisation and timing. Elsewhere it may be necessary to use the array itself for this, or an external detection of array beacons.
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www.sea.co.uka Cohort plc company Wireless In AIV Removing the wires between spacecraft and EGSE has many advantages. –Enables pre-integration of instruments and subsystems over remote links (virtual spacecraft) –Removes necessity for complex test harnesses and simplifies EGSE interfaces –Reduces impact on test facilities such as vacuum chambers –It is cleaner than wire!
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www.sea.co.uka Cohort plc company Wireless and biocontainment Sample return missions pose special problems for planetary protection It is easier to avoid contamination of samples and by samples if the facility is perforated as little as possible Using wireless links to the test piece and inductive links to power supplies avoids facility perforation by harnesses.
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www.sea.co.uka Cohort plc company Wireless SpaceWire Demonstrator This part of the project is developing a wireless bridge to a Spacewire network The demonstrator is using a distributed SpaceWire based avionics system from another ESA project under development by SEA Bridge development is based on existing 4Links SpaceWire- EtherNet bridge. Communication is two- way over the network
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www.sea.co.uka Cohort plc company Wireless CAN-BT demonstrator Under development at SSC, using PRISMA spacecraft model and bridge developed from existing CAN-USB developments The bridge forms a link to a replica bridge which permits analysis of spacecraft traffic but is not intended for module replacement.
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www.sea.co.uka Cohort plc company LPPNS Concept Wireless Sensor Networking –Spacecraft/Planetary applications –IEEE802.15.4 wireless nodes Available Technologies –IEEE802.15.4 MAC/Baseband IP CORE –TinyOS based micro-controller More efficient than ZIGBEE Terrestrial heritage –LEON3 core Digital and Mixed signal ASIC for FM –FPGA & commercial radio for DM/EQM Demonstration system in design applicable to target application areas.
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www.sea.co.uka Cohort plc company LPPNS Development and Demonstration LPPNS Development produces 16 off modules, of which 4 are environmentally characterised. Planetary Demonstrator Spacecraft Demonstrator Demo Modules (16 off) Characterisation (4 modules) COTS Dev Model Demonstration & Test System Radiation Thermal Vibration Launcher environment will be extrapolated from spacecraft mock-up test results of a structured environment
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www.sea.co.uka Cohort plc company LPPNS Intra Spacecraft Demonstrator Example of a structured space application Uses 16 off LPPNS modules Launcher application similar context but tailored to special launcher structural and data handling needs.
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www.sea.co.uka Cohort plc company Planetary Demonstrator Will use 16 off LPPNS modules in use cases still to be determined Will assess issues and solutions in wireless uses on planetary surfaces, particularly propagation, timing and localisation Sensors are unlikely to be representative but throughput will be based on planetary models for seismology, climatology, etc. The performance of the nodes will be scaled so that the restricted area available does not give unrealistic impressions of real-world scenarios
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www.sea.co.uka Cohort plc company Programme Conclusions ESA funded technology development programme progressing the exploitation of wireless network technologies for broad range of space applications. Development of 16 off wireless modules during 2009 with supporting wireless test environment. Demonstration in representative environments: –Spacecraft mock-up. –Planetary mock-up. Environmental testing of wireless modules (including thermal and radiation): –Provides guide for further development to FM modules –Characterises demonstration modules to support possible flight demonstrations. Parallel civil activities ensure coherence and compliance with emerging standards.
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