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OPS Forum SMA Validation PtII 15.08.2008


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This seminar will provide an overview of the new ESTRACK ground station at Santa Maria, Azores, and its first operational usage for the ATV launch in March. Santa Maria station was established to support the Ariane 5 launch of ATV that took place in March this year.

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OPS Forum SMA Validation PtII 15.08.2008

  1. 1. The new ESTRACK Santa Maria Ground station for support of Ariane 5 launch of ATV. Head of Systems and Project Support Section
  2. 2. The Santa Maria Station is presented by: <ul><li>Part 1 Boris Smeds OPS-GSY </li></ul><ul><li>Overview of requirements and technical implementation </li></ul><ul><li>Specific differences compared to a conventional satellite ground station </li></ul><ul><li>Lessons learned, unexpected problems and how they were solved </li></ul><ul><li>Part 2 Gerhard Billig OPS-ONV </li></ul><ul><li>Test and validation </li></ul><ul><li>Operational concept, preparations and launch operation </li></ul>
  3. 3. Requirements <ul><li>Receive telemetry data from Ariane 5 during the launch of ATV and send to Kourou in real time. </li></ul><ul><li>Cover the passes over the Atlantic region. </li></ul>Santa Maria Azores
  4. 4. Time scale of actual implementation. <ul><li>April 2006: Site Inspection </li></ul><ul><li>June 2006: SoW for antenna and related equipment. ITT </li></ul><ul><li>September 2006: PDR for antenna, TM system and power plant </li></ul><ul><li>November 2006: CDR for antenna and TM system </li></ul><ul><li>March 2007: Start of Factory Acceptance Tests </li></ul><ul><li>April 2007: Shelter and TM equipment installation at Santa Maria </li></ul><ul><li>July 2007: Commissioning of Powerplant </li></ul><ul><li>October 2007: Start of antenna commissioning at Santa Maria </li></ul><ul><li>December 2007 / January 2008: Antenna fully validated for AR5 </li></ul>
  5. 5. Station system overview
  6. 6. X-band option <ul><li>To allow reception of Earth observation satellites in the 8025-8400 MHz band the antenna is equipped with a dual feed and dichroic sub-reflector. </li></ul>
  7. 7. Major differences compared to satellite RF-links <ul><li>Dual frequency transmission. One antenna on each side of the spinning launcher </li></ul><ul><li>Telemetry modulation: frequency shift (not CCSDS) , no remnant carrier. 1 Mbps </li></ul><ul><li>No Kepler orbit during launcher propulsion phase. Continuous position updates that may have large errors. </li></ul><ul><li>High angular velocity due to close distance ( 180 km , 7 km/s) </li></ul><ul><li>Communication using HDLC protocol </li></ul><ul><li>ISDN and Inmarsat satellite link to Kourou </li></ul>
  8. 8. Existing concrete platform
  9. 9. Equipment shelter and Telemetry kit <ul><li>Reuse existing design of TM-kit developed for Ariane tracking network by Carlo Gavazzi Space </li></ul>
  10. 10. Calibration tower <ul><li>Guests on existing tower at Pico Alto </li></ul>
  11. 11. Antenna supplied by Indra Espacio. Assembly at factory. <ul><li>Partly new design. 5.5 m dish, Carbon fibre </li></ul>
  12. 12. Antenna installed at Santa Maria <ul><li>X-Y mount (no singularity at zenith) </li></ul>Inmarsat antenna Radio link to calibration tower
  13. 13. Murphy’s law <ul><li>If anything can go wrong, it will. </li></ul>
  14. 14. Filters required to reject UMTS ( mobile phone ) <ul><li>Filters supplied from US company. </li></ul><ul><li>Delayed delivery due to ITAR </li></ul>Receive band
  15. 15. Unexpected problems, wrong paint. <ul><li>Glossy paint was used on the reflector. Feed cover burnt when pointing to the sun during G/T tests. </li></ul><ul><li>Repainting of reflector required </li></ul>
  16. 16. Unexpected problems, autotrack patterns <ul><li>Error in computer simulation of antenna pattern for the autotrack feed. Actual pattern gave larger angular offset than expected. </li></ul>Original feed design
  17. 17. Unexpected problems, autotrack patterns <ul><li>Computer simulation </li></ul>
  18. 18. Antenna tracking pattern measured Error signal
  19. 19. New feed <ul><li>New feed design solved the issue. </li></ul><ul><li>4 lateral dipoles closer together. Sum signal generated by combining signals from the lateral dipoles. </li></ul>
  20. 20. Antenna tracking pattern new feed Error signal
  21. 21. Unexpected problems, bad cables <ul><li>RF cables after Low noise amplifier with 60 dB gain with damaged screen. ( Cut through at manufacturing and covered so not visible ) </li></ul><ul><li>Caused the receive system to self oscillate at 2.2 GHz. </li></ul>Leaking cable
  22. 22. Unexpected problems. RFI from microwave link <ul><li>Microwave links at Azores used the same frequencies as foreseen for Ariane 5. </li></ul><ul><li>Local coordination possible. Microwave links could move to other frequencies. </li></ul>
  23. 23. Unexpected problems. Broken RF cables. <ul><li>Cables from antenna are passing over a cable chain that is bent up to 180 degree each pass. </li></ul><ul><li>Selected coax cables had solid centre conductor not suitable for repeated bending. </li></ul><ul><li>Cables replaced , first temporary with RG223 available on site. </li></ul><ul><li>After AR5 support replaced to RG214 High Flex cables. </li></ul>
  24. 24. Servo system not optimised <ul><li>Large pointing errors when tracking moving targets. </li></ul><ul><li>Servo system software corrected </li></ul>
  25. 25. Rough climate conditions. <ul><li>Rust </li></ul><ul><li>Replace bolts with better quality, and repaint </li></ul>
  26. 26. Useful tool for maintenance