Hubble Space Telescope Engineering Telemetry

1 HST TELEMETRY SYSTEMSHST TELEMETRY SYSTEMSSPACE TELESCOPE SCIENCE INSTITUTESPACE TELESCOPE SCIENCE INSTITUTE

Hubble Space TelescopeHubble Space Telescope

EngineeringEngineeringTelemetryTelemetry

Hubble Space TelescopeHubble Space Telescope

EngineeringEngineeringTelemetryTelemetry

Tom WheelerTom WheelerChris LongChris Long


AgendaAgenda

Onboard Telemetry Systems (Tom)Onboard Telemetry Systems (Tom) Hardware DescriptionHardware Description Data Acquisition and HandlingData Acquisition and Handling Limit CheckingLimit Checking Science Data HeadersScience Data Headers

Ground Systems & Archives (Chris)Ground Systems & Archives (Chris) Data CharacteristicsData Characteristics UtilizationUtilization Data AccessData Access Improvements (SMOV)Improvements (SMOV)


Telemetry FlowTelemetry Flow


Onboard Telemetry SystemsOnboard Telemetry SystemsTom WheelerTom Wheeler


How is SI Engineering Data Acquired Onboard HST?


SI C&DH (Science Instrument Control and Data Handling) Hardware Description

Control Unit/Science

Data Formatter

NASA Standard Spacecraft Computer-1

Support Systems Module

Remote Interface

Units

Power Control Unit

Multiplexed Data Bus


SI C&DH2


RIU (Remote Interface Unit) Hardware Description

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


Engineering Data HandlingThe 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)


Science Data Handling

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.


SI Interfaces


Acquisition of Engineering Data from SIsThe 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


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


Limits Monitoring

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)


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

Data Word Number Contents

1 Observation Number (least significant 8 bits of the 16-bit word), Requesting SI Source ID (most significant 8 bits of the 16-bit word)

2-130 ACS Portion of the Current Value Table (CVT)

131-259 NICMOS Portion of the CVT

260-388 STIS Portion of the CVT

389-517 COS Portion of the CVT

518-646 WFC3 Portion of the CVT

647-775 SI C&DH Portion of the CVT

776-795 SSM PIT

796-855 Forward Linked Data

856-877 ACS Unique Data

878-899 NICMOS Unique Data

900-921 STIS Unique Data

922-943 COS Unique Data

944-965 WFC3 Unique Data

Standard Header Packet Format


SI Internal Science Data Headers• 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.

These two snapshots form the .SPT file


Other Lesser Known Telemetry

• 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.


Data Transmission • 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.


Ground Processing/Storage Ground Processing/Storage Chris LongChris Long


DownlinkDownlink


Telemetry PipelineTelemetry Pipeline

Data WarehouseData Warehouse100% Mission

Data WarehouseData Warehouse100% Mission

Central StoreCentral StoreScience Inst. FOF

Central StoreCentral StoreScience Inst. FOF

Local ArchiveLocal Archive100% SI Monitors

Local ArchiveLocal Archive100% SI Monitors


Data Quality (Gaps)Data Quality (Gaps)

• Real-time: Viewable with gaps.Real-time: Viewable with gaps.• Recent: All-points w/gaps.Recent: All-points w/gaps.• Historical: Change only, no gaps.Historical: Change only, no gaps.


Data UtilizationData Utilization

AnalysisAnalysis• Random data extraction and manipulation.Random data extraction and manipulation.

TrackingTracking• Following evolutions in real-time.Following evolutions in real-time.• May include rapid turnaround plotting.May include rapid turnaround plotting.

MonitoringMonitoring• Regular products of systems of known interest.Regular products of systems of known interest.

TrendingTrending• Periodic long-term visualization Periodic long-term visualization

– Unrecognized performance variation.Unrecognized performance variation.• Consumable statistics.Consumable statistics.


Archive AccessArchive Access

CCS Data WarehouseCCS Data Warehouse• Official HST engineering archive.Official HST engineering archive.• Requires software and HSTnet/CCS accounts.Requires software and HSTnet/CCS accounts.

• ITAR and support issues.ITAR and support issues.

Local SI Data Archive Local SI Data Archive • Engineers maintain SI monitor archive.Engineers maintain SI monitor archive.• No access limitations.No access limitations.

• But, no tools…But, no tools…


Directory of MonitorsDirectory of Monitors

No Such Thing. Monitors Listed As:No Such Thing. Monitors Listed As:

SpacecraftSpacecraft• 1000’s maintained by systems engineers.1000’s maintained by systems engineers.

ObservatoryObservatory

• MSIDMSID U169U169• Mnemonic:Mnemonic: USCADCLKUSCADCLK

FOCFOC 205205 COSTARCOSTAR 157157 ACSACS 823823FOSFOS 200200 WFPC2WFPC2 255255 COSCOSGHRSGHRS 315315 NICMOSNICMOS 479479 WFC3WFC3HSPHSP 208208 STISSTIS 607607WFPCWFPC 217217 NCSNCS 790790


Products (but no standards)Products (but no standards)

ContentContent• All-points or change-only.All-points or change-only.• Merging recorded data into ongoing analysis..Merging recorded data into ongoing analysis..

TimeTime• MJD, UTC, Day of Year.MJD, UTC, Day of Year.

Output FileOutput File• Delimited/interleaved/multiple independent files.Delimited/interleaved/multiple independent files.

ProductsProducts• Flat file, preload Excel, statistics, or plots.Flat file, preload Excel, statistics, or plots.

27 HST TELEMETRY SYSTEMSHST TELEMETRY SYSTEMSSPACE TELESCOPE SCIENCE INSTITUTESPACE TELESCOPE SCIENCE INSTITUTE 27 HST TELEMETRY SYSTEMSHST TELEMETRY SYSTEMSSPACE TELESCOPE SCIENCE INSTITUTESPACE TELESCOPE SCIENCE INSTITUTE


Telemetry ATMTelemetry ATM

Directory



Forward PlanForward Plan


ImprovementsImprovements Telemetry directoryTelemetry directory Post productsPost products Extraction interfaceExtraction interface Visualization interfaceVisualization interface

SMOVSMOV Proactive monitor programProactive monitor program

Improved analysis toolsImproved analysis tools

ImprovementsImprovements Telemetry directoryTelemetry directory Post productsPost products Extraction interfaceExtraction interface Visualization interfaceVisualization interface

SMOVSMOV Proactive monitor programProactive monitor program

Improved analysis toolsImproved analysis tools

30 HST TELEMETRY SYSTEMSHST TELEMETRY SYSTEMSSPACE TELESCOPE SCIENCE INSTITUTESPACE TELESCOPE SCIENCE INSTITUTE 30 HST TELEMETRY SYSTEMSHST TELEMETRY SYSTEMSSPACE TELESCOPE SCIENCE INSTITUTESPACE TELESCOPE SCIENCE INSTITUTE

Engineering Support Questions?Engineering Support Questions?

Documents

Hubble Space Telescope Engineering Telemetry