Hubble Space Telescope Engineering Telemetry

1. Hubble Space Telescope Engineering Telemetry Tom Wheeler Chris Long

2. Agenda

3. Telemetry Flow

4. Onboard Telemetry Systems Tom Wheeler

5. How is SI Engineering Data Acquired Onboard HST?

6. SI C&DH (Science Instrument Control and Data Handling) Hardware Description NASA Standard Spacecraft Computer-1 Remote Interface Units Multiplexed Data Bus Control Unit/Science Data Formatter Support Systems Module Power Control Unit

7. SI C&DH2

8. RIU’s are the common communication interface to the SIs (located within the SIs). RIU’s are implemented in redundant pairs, with seven pairs on HST: one pair for each of the five SI’s plus a pair the SI C&DH WFPC-2 has an additional RIU used for the AFMs. another pair was installed during SM-3B for the Cooling System only one of each pair is fully active at a time Each RIU provides: 8 lines for serial digital commands 64 lines for discrete commands 64 lines for sampling serial digital, analog, and bi-level telemetry points EUs (Expander Units), that piggy-back onto a RIU, add additional 64 telemetry inputs and are used on some SIs RIU (Remote Interface Unit) Hardware Description

9. The SI C&DH has two telemetry collection modes. Fixed Format (NSSC-1 is safed) are: AF, FF, HF, PF, TF, XF, YF, ZF, C, D, E (rarely used except for Safe modes) Normal Format (NSSC-I is operating) are: AN, FN, HN, PN, TN, XN, YN, ZN Spacecraft Telemetry Distribution: Total 64 Words/minor frame 10 words each for SI = 50 words 14 words for SI C&DH Same for every operational format (regardless of 4 or 32K rates) Engineering Data Handling

10. The CU/SDF collects science data from all five SIs for transmission to the SSR (in SSM) or processing within the NSSC1. Also collects memory dumps from the NSSC1 for transmission to the ground via the SSM. Output Rates: 1Mb (used for all current/future SIs science data) 32K (not used currently) 4K (ESB Dumps and SI Memory logs) Ability to add RS (Reed-Solomon, an error correcting code) or PN (Pseudorandom Noise) encoding to data. Science Data Handling

11. SI Interfaces

12. The are 3 type of Engineering data collections Normal Engineering Data (NED) - digital serial data to RIU RIU direct - analog, bi-level Special Engineering Data (SED) - digital serial data to RIU Normal Engineering Data (NED) Consists of key instrument parameters (analog and digital) giving visibility into instrument state and operations Analog engineering data is sampled directly from A/D Electronics (includes temperatures, voltages, etc.) located in: SES A/D electronics (all new SIs) CEBs (ACS, STIS, and WFC3 CCD) A/D electronics DEB (WFC3 IR) A/D electronics Mechanism status and position information is collected MIE (ACS & STIS, DIB for COS) status is collected NED collection task runs every 2.0 sec. except 0.5 sec. for NICMOS Collected data is stored in current value table for subsequent transmission to the SI C&DH and is used by the CS’s limit checking task A circular A/D data buffer maintains approximately 2 minutes of data Acquisition of Engineering Data from SIs

13. RIU Direct Data Telemetry Analog and digital telemetry collected directly by the RIU. SI need not be operating. Used to monitor key telemetry while SI in SAFE mode but is also used during normal ops. Special Engineering Data Telemetry 28 (used to be 35) bytes sent to the NSSC-1 every minor frame (0.5 seconds) Contains information used by the NSSC-1 Safing requests, suspend requests, executive status buffer messages, checksum indicator, minor frame count, flight software state (boot/operate), slew requests and reason for last reset. Acquisition of Engineering Data from SIs

14. Two Types of limit monitoring NSSC Executive (Safing Application Processor) Once a minute Only monitors RIU direct telemetry points 3 strikes and you’re out will cause suspend/safing SI Control Section Limit Checking Done at the same rate as NED Done in Boot and in Operate Out of limits may cause suspend/safing (depends upon action in FSW) Limits Monitoring

15. Standard Header Packet • The Standard Header Packet (SHP) is a fixed format data log generated by the NSSC-1 sent out prior to an instrument science data dump. The format of the SHP is shown in below. See DM-03D Rev M for BL9.0 for a complete description. • Uplinked programmatic information for data identification • Portions of each SI Current Value Table • Copies of the most recent PIT tables • Unique log for each SI, provided by that SI’s application processor Standard Header Packet Format

16. The SI internal science header is a fixed format data log generated by the CS and sent out as the first line (965 words) in an instrument science data dump. A complete description of the internal science header is contained in the DM-06 for each SI. An ACS example is shown below: 1-255 (255 words) contain exposure specific information, e.g., programmatic numbers, instrument configuration, TDF responses, detector information. Some keywords found in science data’s FITS header are derived from this data. 256-605 (350 words) Eng. snapshot 1 606-955 (350 words) Eng. snapshot 2 For most science data files, the 1st snapshot is taken prior to the exposure start and the 2nd is taken just after the exposure completes. The one exception is when one exposure extends over multiple science data dumps, i.e., time-tag exposures. In this case, the first dump contains the 1st snapshot before the exposure starts and 2nd prior to the start of the dump. Subsequent dumps will only have the 2nd snapshot populated. SI Internal Science Data Headers These two snapshots form the .SPT file

17. NSSC-1 Executive Status Buffer Messages Reports when an error or out of limits violation occurs with the SIs or SI C&DH. This log is always downlinked. SI Instrument Error Logs Reports when an error or out-of-limits violation occurs within an SI. This log is sometimes sent to the ground. Engineering Reports Reports status and errors within the SI C&DH. Always downlinked in Normal mode. Other Lesser Known Telemetry

18. Engineering telemetry and science data are passed from the SIC&DH to the SSM (Support Systems Module) for transmission to TDRSS or are recorded on the SSR (Solid State Recorder) for later transmission. Data Transmission

19. Ground Processing/Storage Chris Long

20. Downlink

21. Telemetry Pipeline Local Archive 100% SI Monitors Data Warehouse 100% Mission Central Store Science Inst. FOF

22. Data Quality (Gaps)

23. Data Utilization

24. Archive Access

25. Directory of Monitors

26. Products (but no standards)

27. SPACE TELESCOPE SCIENCE INSTITUTE SPACE TELESCOPE SCIENCE INSTITUTE HST TELEMETRY SYSTEMS HST TELEMETRY SYSTEMS 27

28. Directory SPACE TELESCOPE SCIENCE INSTITUTE SPACE TELESCOPE SCIENCE INSTITUTE Telemetry ATM HST TELEMETRY SYSTEMS HST TELEMETRY SYSTEMS 28

29. SPACE TELESCOPE SCIENCE INSTITUTE SPACE TELESCOPE SCIENCE INSTITUTE Forward Plan • Improvements • Telemetry directory • Post products • Extraction interface • Visualization interface • SMOV • Proactive monitor program • Improved analysis tools HST TELEMETRY SYSTEMS HST TELEMETRY SYSTEMS 29

30. SPACE TELESCOPE SCIENCE INSTITUTE SPACE TELESCOPE SCIENCE INSTITUTE Engineering Support Questions? HST TELEMETRY SYSTEMS HST TELEMETRY SYSTEMS 30