RF Wireless in Planetary Exploration and AIV

1. E W Pritchard Systems Engineering & Assessment Ltd RF Wireless in Planetary Exploration and AIV

2. Wireless Application Areas Spacecraft Launcher Low Power Wireless Sensors Robust Networking EMC Analyses Structured (spacecraft) demonstrator Planetary demonstrator Flight demonstrator? Planetary CAN-BT Bridge & demo SpW-WiFi Bridge & demo Wireless Test Port EMC Analyses AIV

3. 2009 2010 Today Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb LPPNS Building Blocks, Requirements LPPNS LPPNS Demonstrator Demonstrator & Preliminary Design Design Development and Build Tests Application Demonstration Use Cases Test Environment EGSE/AIT Requirements EGSE/AIT EGSE/AIT EGSE/AIT & Preliminary Design Design Procure/Build Test and Demonstration Jul 08 Dec 08 Mar 09 Sep 09 Dec 09 LPPNS LPPNS PDR LPPNS CDR LPPNS TRR LPPNS TRB Concept Review EGSE/AIT CDR Oct 08 Apr 09 Oct 09 EGSE/AIT PDR EGSE/AIT TRR EGSE/AIT AR RF Wireless Outline Schedule

4. 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

5. 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.

6. 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.

7. Possible Seismometer

8. 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

9. 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.

10. 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!

11. 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.

12. 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

13. 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.

14. 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 signalASIC for FM • FPGA & commercialradio for DM/EQM • Demonstration system in design applicable to target application areas.

15. LPPNS Development and Demonstration Launcher environment will be extrapolated from spacecraft mock-up test results of a structured environment LPPNS Development produces 16 off modules, of which 4 are environmentally characterised. Demonstration & Test System COTS Dev Model Demo Modules (16 off) Radiation Thermal Vibration Characterisation (4 modules) Planetary Demonstrator Spacecraft Demonstrator

16. 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.

17. 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

18. 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.