THEMIS/GBO Review 1 Banff, March 29, 2006 Ground Based Observatories (GBO) System Design Overview Operational Status Lessons Learned S. E. Harris University of California - Berkeley

THEMIS/GBO Review 2 Banff, March 29, 2006 GBO Components AC Power Ground Magnetometer (GMAG) Telesat Dish Iridium GPS All Sky Imager (ASI) Observatory Support Equipment (OSE) inside the “Hut” enclosure Internet Variations possible at some sites: Existing magnetometer “Hut” enclosure not needed Existing Internet connection

THEMIS/GBO Review 3 Banff, March 29, 2006 Complete Installation at McGrath

THEMIS/GBO Review 4 Banff, March 29, 2006 All Sky Imager (ASI) Main Components Camera, Starlight Xpress, MX716 –Designed for amateur astronomy –CCD Format: Interline transfer, 376 x 290 pixels (binned), 8mm diag. –Cooled with TEC for reduced dark current All Sky Lens –Telecentric design by Keo Consultants –Full hemisphere viewing, full resolution obtained 256 x 256 image Environmental Enclosure with Sun Shade

THEMIS/GBO Review 5 Banff, March 29, 2006 ASI Unit Test Summary Acceptance Tests: FOV (>170°) Exposure Time (duration at least 1 sec) Spectral Response –Produce detectable response to source radiance < 10kR –Goal < 1kR –Passband 400 – 750nm –1 sec exposure duration Spatial Resolution (>250 pixel image diameter) –Verify point source response Cadence (better than 10s) –Goal < 3s Record dark and bias images (room temperature) Pre-Shipment: Focus adjustment and verification Alignment verification (top of image relative to alignment datum) Heater control functional test Sun Shade solenoid functional test (#iterations: 360) Internal mechanical inspection checklist (thm_gbo_116) Final functional test and System Burn-in (duration: several days)

THEMIS/GBO Review 6 Banff, March 29, 2006 ASI Responsivity Testing Data report: thm_gbo_118 Recorded on all Imagers: On Axis spectral response Off Axis spectral response Dark vs exposure time Resolution

THEMIS/GBO Review 7 Banff, March 29, 2006 ASI Resolution Testing On-Axis40º Off-Axis80º Off-Axis

THEMIS/GBO Review 8 Banff, March 29, 2006 ASI Enclosure Design Design: Allison Park Group, Inc. Heaters S.S. Enclosure Acrylic Dome

THEMIS/GBO Review 9 Banff, March 29, 2006 Sun Shade ASI must survive non-operating exposure to daytime sun CCD is Sony ICX249AL –Plastic “microlens” on each pixel, transmission reduction w/ exposure to UV All Sky Lens uses Peleng Fisheye f/3.5 –A/R coating exhibited discoloration after one summer in ATHA Solenoid drive actuates to close shade Falls open when solenoid power is removed

THEMIS/GBO Review 10 Banff, March 29, 2006 ASI Enclosure Performance ASI installed at Ft. Yukon, AK Dome: Generally stays clear of snow without intervention Some ice buildup on flange Heating: Maintains 60°  T using about 50W avg. heat power Total heating power available is 240W (60W in dome)

THEMIS/GBO Review 11 Banff, March 29, 2006 Ground Magnetometer GPS Receiver (included at all GBO sites)  Antenna and Electronics Integrated into one package  NTP compatible (1msec time accuracy) Fluxgate Magnetometer (sensor shown below)  ±72KnT dynamic 0.01nT Resolution (~23 bits)  Offset DAC system for 256 possible ranges per axis  2 Vectors per second data rate  Low Power < 4W  USB interface for data retrieval and firmware upload

THEMIS/GBO Review 12 Banff, March 29, 2006 GMAG Installation Fluxgate Magnetometer Installed at Athabasca

THEMIS/GBO Review 13 Banff, March 29, 2006 OSE Layout (1) Rack Mount Shipping Case (12U) System Computer GMAG Interface Electronics APS Serial Switch Swappable Hard Drive (2 ea) Iridium modem UPS 28”

THEMIS/GBO Review 14 Banff, March 29, 2006 OSE Layout (2) Power Control Unit CR10X Datalogger UPS ASI Power Supply CR10X Battery

THEMIS/GBO Review 15 Banff, March 29, 2006 Power Control Unit (PCU) PCU Features CR10X Datalogger is the environment controller for GBO –Extended temperature range (-55º to +85ºC) –Always operating and remotely accessible (via Iridium) –Low power consumption (battery can operate it for months) –Simple programming and data logging capability Provides room temperature environment inside OSE and ASI –Enables use of standard commercial computers, hard drives, etc. –Implements graceful shutdown of system in either event of: –Loss of Power –Loss of Temperature (either too high, or too low) CR10X is the analog & digital I/O peripheral for System Computer Provides “watchdog” function for System Computer (PC)

THEMIS/GBO Review 16 Banff, March 29, 2006 Power Control Unit Interfaces

THEMIS/GBO Review 17 Banff, March 29, 2006 OSE Heating / Cooling Devices Small Space Heaters 175W, 120VAC, 2 ea Solid State Air Conditioner 163W Capacity 120VAC Power

THEMIS/GBO Review 18 Banff, March 29, 2006 “Hut” Enclosure “A Box within a Box” Internal Rack Mount Case for Equipment (Doubles as Shipping Case) External Insulated Environmental Enclosure

THEMIS/GBO Review 19 Banff, March 29, 2006 Hut Performance No heating in Hut required down to –40ºC GBO#10, Ft. Smith Cooling required above –5ºC GBO#10, Ft. Smith

THEMIS/GBO Review 20 Banff, March 29, 2006 Instrument Data Flow System Computer ASI GMAGTelesat Modem Hot Swap Hard Drive(s) USB Serial I/O 10/100 Base T GPS Internet

THEMIS/GBO Review 21 Banff, March 29, 2006 Status of Operations Number of GBOs Deployed: 11 Installation and logistics can be difficult Monitoring and maintaining is harder Some operational hazards that we’ve survived so far: Cold –e.g. door to the shack stuck open Hot –e.g. stuck thermostat in the shack Power –generally it’s been reliable, but outages are a fact of life Inaccessibility –Ekati and Inuvik RF Interference (More on this later) Internet connection outages –data back up is working fine Software issues –system processes can hang up (USB interfaces, NTP daemon) –periodically we need to reboot the system Non-responsive custodian

THEMIS/GBO Review 22 Banff, March 29, 2006 System Uptime Initial analysis, 8 of 10 stations analyzed Based on availability of CR10X records logged on site At each station, number of records is averaging 97.5% –Of 288 records maximum per day Indicates the systems are up and running normally most of the time

THEMIS/GBO Review 23 Banff, March 29, 2006 Learning and Improving System issues are addressed in Problem Reports PFRs describe problem and corrective action We track PFRs for each station –Leaves a paper trail of changes for each site –A copy also is attached to site log on ‘wiki’

THEMIS/GBO Review 24 Banff, March 29, 2006 Lessons Learned - Prototype Ice buildup on ASI dome Added dome heaters Insulation outgassing in ASI Changed material to foil- faced air pillow

THEMIS/GBO Review 25 Banff, March 29, 2006 Lessons Learned (1) IssuePFRDescription / Resolution ASI cable length A deployment issue first increased to 60’ settled on 100’ Changed ASI supply to regulated 12V (60’) Increased sun shade solenoid drive to 24VAC Changed ASI 12V supply to meet in-rush current Modify ASI power interface wiring (100’) Increased sun shade solenoid drive to 28VAC ASI Power Diagram

THEMIS/GBO Review 26 Banff, March 29, 2006 Lessons Learned (2) IssuePFRDescription / Resolution ASI USB Interface Susceptible to EMI, causes lock up Design is “always on” Add’l power line filtering on Starlight Xpress board Design remote-control USB Disconnect device Enables an easy power reset option Inuvik is skipping exposures to elim. RF interference Modified USB Board USB Disconnect Device Prototype

THEMIS/GBO Review 27 Banff, March 29, 2006 Lessons Learned (3) IssuePFRDescription / Resolution System monitoring “more is better” Add AC line current monitor Add monitor for PC +5V Add monitor on ASI power supplies ASI Power Supply Overheating -015Modify power brick, add heat sink and fan Overheated PC Board courtesy of Mikko Syrjasuo Modified Starlight Brick

THEMIS/GBO Review 28 Banff, March 29, 2006 Lessons Learned (4) IssuePFRDescription / Resolution Component failures Ekati – USB hard drive failed, PC would not boot Atha – PC power supply failed, blew internal fuse Obsolescence-022USB Extender device now unavailable, changing all to make them interchangeable ASI Data Interface Diagram

THEMIS/GBO Review 29 Banff, March 29, 2006 Open PFRs IssuePFRDescription / Resolution Iridium modem config Learning curve -016APS serial switch auto-configures modem on reset Power reset modem and APS every day Learn all failure modes Recently discovered a situation where modem and APS switch can get into hung state – investigation is ongoing GMAG restart problem-007Problem associated with GMAG USB interface, does not restart correctly if system reboots when it’s cold Very infrequent occurrence, can be handled by operator intervention