ESA UNCLASSIFIED – For Official Use Background for Downlink Plug-in MAPPS User-Group Meeting

Plugin Background| Jayne Lefort /Richard Carr| 1 October 2015 | Slide 2 ESA UNCLASSIFIED – For Official Use Driven by Solar Orbiter Mission Characteristics Bumpy Data Generation Profile. In- situ measure all the time Remote Sensing during 3 x 10 day windows every orbit (6 months) Approx. 165 day orbit 4 in-situ and 6 RS instruments Highly variable data rates. Factor 20 Science Data rates vary for each instrument (factor 100) Single transmitter High Data Latency

Plugin Background| Jayne Lefort /Richard Carr| 1 October 2015 | Slide 3 ESA UNCLASSIFIED – For Official Use Driven by Downlink Concept Data dependencies between instruments Even share of downlink would lead to large latencies on high producers days Pro-rata downlink chosen (higher data generation allocation higher => high downlink share). days In-Situ Remote-Sensing Equal downlink Pro-Rata downlink

Plugin Background| Jayne Lefort /Richard Carr| 1 October 2015 | Slide 4 ESA UNCLASSIFIED – For Official Use Practical Implementation 1 -Platform data comes down on daily on VC1 2 -Payload HK, Low Latency Data, and Selective come down daily on VC2 (Service 13/FTS) 3 -Normal Science “bulk” comes down on VC3, Service 15 (round robin) in time that is left. This time needs to be divided up pro-rata by giving a store a pro-rata share of time with priority. Time available for S15 varies; it depends on pass duration, data volume on higher priority channels and TM rate.

Plugin Background| Jayne Lefort /Richard Carr| 1 October 2015 | Slide 5 ESA UNCLASSIFIED – For Official Use To split the time for bulk up we would like to change the priorities from the command timeline. To do this we need to know: Duration of S15 downlink. Start Time of S15 (VC3 activation) End of pass Time of S15 activation depends on Volume of platform data Amount of payload HK, SD and LL data Data rate Some of this information is needed from simulation itself. Practical Implementation

Plugin Background| Jayne Lefort /Richard Carr| 1 October 2015 | Slide 6 ESA UNCLASSIFIED – For Official Use Once the start time of VC3 is known, the time S15 time is split among the stores according to a table (TDR – Table of downlink ratios) The TDR defines the ratios per store from time A to B. Typically it will change 2 or 3 times per orbit. For each period it gives a ratio value per store, based on orbital data allocation and generation profiles. The sum of all ratios is 1 The plugin has two priority values: High and Low (configurable in the TDR) Its gives all stores the a slot of appropriate time at high priority, during this time the other stores in the table have the low priority value. Plugin Implementation -TDR

Plugin Background| Jayne Lefort /Richard Carr| 1 October 2015 | Slide 7 ESA UNCLASSIFIED – For Official Use Not 1 plug-in but 2. Only a modelling plugin can make changes (to priorities) during simulation. But changes dependant on: Result of simulation to date (start time of VC3 d/link) Knowledge of future events (predicted end-time of dump) Only a commanding plugin can look ahead in the timeline. Internal Plugin Implementation

Plugin Background| Jayne Lefort /Richard Carr| 1 October 2015 | Slide 8 ESA UNCLASSIFIED – For Official Use Inter-plugin communication. Initial idea to pass via events on timeline. Complex smuggling mechanism. Since can share memory. We build two plug-ins as a single library. Load twice - commanding and modelling. Internal Plugin Implementation

Plugin Background| Jayne Lefort /Richard Carr| 1 October 2015 | Slide 9 ESA UNCLASSIFIED – For Official Use Commanding Initialise Find TDR file. Register callback method. Commanding Callback Fetch Dump End times. Create TDR handler (Prioritiser). Stash the above. Modelling Initialise Register VC activation cyclic callback. Register DumpEnd callback. Used to end cyclic callback. VC activation callback (1 st call) Prioritiser calculates list of absolute times of priority switches. VC activation callback (subsequent) If time for next store, switch. Dump End callback Deactivate VC cyclic callback. Reset store states to deactivated (99) Internal Plugin Sequence

Plugin Background| Jayne Lefort /Richard Carr| 1 October 2015 | Slide 10 ESA UNCLASSIFIED – For Official Use Sharing of memory is a great improvement. Much simpler plugins. Assuming all this works. Would be even simpler if could: Register callbacks during simulation. Examine timeline events from Modelling plugin initialise or new method. Observations