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Robert Ergun University of Colorado

Robert Ergun University of Colorado. Burst System Science Requirements. MMS Burst System.

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Robert Ergun University of Colorado

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  1. Robert Ergun University of Colorado Burst System Science Requirements

  2. MMS Burst System • The MMS burst system is required to obtain high-resolution data in regions of magnetic reconnection. The system is needed since the high resolution science data telemetry rate (~2.6 Mbit/s) far exceeds the average telemetry rate of the MMS spacecraft. • The MMS satellites have a capability of transmitting 4 Gbit/day of science data. This transmission rate allows for roughly 15-20 minutes of high resolution data per day.

  3. MMS Burst System: Basic Plan • Basic Plan: Obtain ~15 (required; 20 goal) minutes of burst per day. • Phase 1 orbit: ~1 day -> 20 min. burst data. • Phase 2 orbit: ~3 days -> 1 hour of burst data.

  4. MMS Burst System • The four main elements of burst system are: • Instruments must produce four types of data: • Slow Survey • Fast Survey • Burst Data • Trigger Data • The CIDP must have the capability to store (on-board) the high-time resolution data in the regions of scientific interest on each of the SC for an entire orbit. • The science team must implement a method to select the allocated volume of high-time resolution data (resulting in an average of ~2.7 Gbit/day) for transmission to the ground. • The SOC/MOC must manage the burst memory to transmit the selected data and free unwanted data.

  5. (1) Data Types/Overview Trigger Data Each of the instruments is required to produce: Slow Survey Data Fast Survey Data Burst Data Trigger Data Trigger Data are designed for burst data selection. CDQ Algorithm Instrument A Survey Data Burst Data TDN CDQ Mass Memory CIDP/ Control Transmit Survey Data Burst Data Uplink Automatic Selection Memory Management (Algorithm) Scientist Selection (Manual) SOC

  6. (2) On board storage (CIDP). • The four main elements of burst system are: • Instruments must produce four types of data: • Slow Survey • Fast Survey • Burst Data • Trigger Data • The CIDP must have the capability to store (on-board) the high-time resolution data in the regions of scientific interest on each of the SC for an entire orbit. • The science team must implement a method to select the allocated volume of high-time resolution data (resulting in an average of ~2.7 Gbit/day) for transmission to the ground. • The SOC/MOC must manage the burst memory to transmit the selected data and free unwanted data.

  7. (2) On board storage (CIDP). • The burst memory is 96x29 Bytes (96 G2Bytes). • It is partitioned into ~24,500 4x26 Byte (4 M2Bytes) “pages”. • Each page will store 10 s of data. The 10 s is the minimum Dt for choosing burst events. Nominally, 10s of burst data will fill 2.5 Mbytes, so a part of the pages are empty. This gives us the flexibility to increase burst data rate if needed. Unfilled sections will not be transmitted. • ~ 48G2Bytes are needed to store one P2B orbit (12,125 pages). Typically, ~ 350 pages can be transmitted in a P2B orbit (averaging to 120 pages per day). Roughly 2% of burst data.

  8. (2) On board storage (CIDP). Free 39.6 x 29 Bytes Fast Survey 0.34 Slow Survey 0.06 Off-Line 8 (min) Burst 48 x 29 Bytes Burst memory has ~40% margin for a P2B orbit. Data selected for down-link. Drawing NOT to scale!

  9. (3) Data Selection • The four main elements of burst system are: • Instruments must produce four types of data: • Slow Survey • Fast Survey • Burst Data • Trigger Data • The CIDP must have the capability to store (on-board) the high-time resolution data in the regions of scientific interest on each of the SC for an entire orbit. • The science team must implement a method to select the allocated volume of high-time resolution data (resulting in an average of ~2.7 Gbit/day) for transmission to the ground. • The SOC/MOC must manage the burst memory to transmit the selected data and free unwanted data.

  10. (3) Data Selection Science Criteria for selecting burst events.

  11. (3) Data Selection Trigger data (TDNs) are produced on a 10 s cadence in correspondence with the 10 s pages of the burst memory. FIELDS produces 16 quantities including magnetic field levels and fluctuations, density and density fluctuations, and electric field and wave activity monitors. FPI produces 11 quantities including electron fluxes, ion fluxes, and variability. HPCA produces 2 quantities including H+ and O+ fluxes. EPD produces 5 quantities including high-energy electron and ion anisotropy and variability.

  12. (3) Data Selection CDQ (Cycle Data Quality) Calculation (made on-board and by the SOC). For each 10 s “page” (and for each SC), the TDNs (trigger data) are combined with a table-driven formula:

  13. (3) Data Selection BDQ/MDQ (Burst/Mission Data Quality) Calculation performed by the SOC: The CDQ’s are time-averaged and all four SC are combined to form a mission wide burst quantity:

  14. (3) Trigger Data

  15. (3) Trigger Data

  16. (3) Trigger Data

  17. (3) Data Selection Trigger Data CDQ Algorithm Instrument A Survey Data Burst Data TDN CDQ Mass Memory CIDP/ Control Transmit Survey Data Burst Data Uplink Automatic Selection Memory Management (Algorithm) Scientist Selection (Manual) SOC

  18. (3) Data Selection Trigger Data • Automatic Data Selection (Default – always performed): • Automatic data selection used trigger data (TDNs) to calculate CDQ, BDQ, and MDQ. • The automatic selection of burst periods will be entirely based on MDQ. CDQ Algorithm Instrument A Survey Data Burst Data TDN CDQ Mass Memory CIDP/ Control Transmit Survey Data Burst Data Uplink Automatic Selection Memory Management (Algorithm) Scientist Selection (Manual) SOC

  19. (3) Data Selection Trigger Data • Scientist Data Selection: • The “scientist in the loop” can override the automatic data selection. • The scientist decision will be based on survey data as well as TDNs and MDQ values. • The scientist selection can have an algorithm based on survey data (e.g. moments, magnetic field) CDQ Algorithm Instrument A Survey Data Burst Data TDN CDQ Mass Memory CIDP/ Control Transmit Survey Data Burst Data Uplink Automatic Selection Memory Management (Algorithm) Scientist Selection (Manual) SOC

  20. (3) Data Selection Trigger Data • Scientist Data Selection: • The “scientist in the loop” can override the automatic data selection. • The scientist decision will be based on survey data as well as TDNs and MDQ values. • The scientist selection can have an algorithm based on survey data (e.g. moments, magnetic field) CDQ Algorithm Instrument A Survey Data Burst Data TDN CDQ Mass Memory CIDP/ Control Transmit Survey Data Burst Data Uplink Automatic Selection Memory Management (Algorithm) Scientist Selection (Manual) SOC

  21. (3) Data Selection Trigger Data • Scientist Data Selection: • Scientist Data Selection can be improved with “Processed Survey Data” • Processed Survey Data: • Ion Density • Ion Velocity • Bx, By, Bz CDQ Algorithm Instrument A Survey Data Burst Data TDN CDQ Mass Memory CIDP/ Control Transmit Survey Data Burst Data Uplink Automatic Selection Memory Management (Algorithm) Scientist Selection (Manual) SOC

  22. (3) Science Displays • For each of the SC: • Ion Energy Flux (Spectra) • Electron Energy Flux (Spectra) • Magnetic Field (Bx, By, Bz, and |B|) • Electric Field (Ex, Ey, Ez, and E||) • Ion Velocity (Vx, Vy, Vz, and |V|) • Density • COMPOSITE (Trigger Display) • CDQ SC1/2/3/4 • MDQ • |B| SC1/2/3/4 • N SC1/2/3/4 • |V| SC 1/2/3/4

  23. (3) Burst Durations Burst Pages are 10 s (minimum resolution): Minimum: 60 s (Subsolar) Maximum: 600 s (Tail) Must include SC delays. 10 Minutes

  24. (3) Science Management • “Operating” or “Burst” Scientist • The PI will delegate the data selection task to an operating scientist who is responsible for the day-to-day operation of the MMS mission. • The operating scientist will be the single point of contact to the SOC/MOC for burst system management. • The operating scientist may employ the aid of instrument leads and the MMS theory group in making burst data decisions. • Automatic Selection Algorithm: • The PI has the authority to set the tables in the automatic selection algorithm. He may delegate this authority to the Operating/Burst Scientist.

  25. (4) Burst Memory Management • The four main elements of burst system are: • Instruments must produce four types of data: • Slow Survey • Fast Survey • Burst Data • Trigger Data • The CIDP must have the capability to store (on-board) the high-time resolution data in the regions of scientific interest on each of the SC for an entire orbit. • The science team must implement a method to select the allocated volume of high-time resolution data (resulting in an average of ~2.7 Gbit/day) for transmission to the ground. • The SOC/MOC must manage the burst memory to transmit the selected data and free unwanted data.

  26. Phase 2B Orbit Scenario

  27. (4) Burst Memory Management

  28. Phase 2B Orbit Scenario Burst “metadata” (CDQs and trigger data; memory map) and survey data are transmitted near the end of the region of interest. Using survey and metadata, operating scientist decides which periods of burst to save (“good” data). The SOC prepares burst management commands which (a) move the “good” data off-line (saved) and (b) free the remaining memory for the next orbit. Off-line burst data is transmitted at the beginning of the region of interest.

  29. Testing (Overview) The trigger data will be tested by instrument teams. The trigger data transfer to the CIDP will be tested by individual instruments. The CIDP will be tested with fabricated TDN data. A full-up test on a single satellite will be performed by at the IS suite integration. The instruments will be stimulated, the SOC/MOC must capture the data from the stimulation. Mission-wide test will be performed with simulated data.

  30. Conclusions We have implemented or planned the four main elements of burst system: The MMS instruments produce needed types of data. The CIDP has the needed storage capability. The science team has implemented a method to select burst data. The MOC/SOC has a plan to manage the burst memory. A test plan is in place.

  31. BACKUP

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