1. THEMIS/GBO Engineering Peer Review 1 UCB, Oct. 17, 2003 Ground Based Observatories (GBO) Observatory System Design Stewart Harris - UCB

2. THEMIS/GBO Engineering Peer Review 2 UCB, Oct. 17, 2003 GBO External Components AC Power GMAG Telesat Dish Iridium GPS All Sky Imager Computer Enclosure Internet

3. THEMIS/GBO Engineering Peer Review 3 UCB, Oct. 17, 2003 System Design Summary Presentation Overview: Environmental Enclosure Requirements Temperature Control Power Control –And Handling Power Outages Remote Intervention Instrument Data Collection –Computer Selection Enclosure Design

4. THEMIS/GBO Engineering Peer Review 4 UCB, Oct. 17, 2003 The Environment USGS Tundra monitoring site Alaskan Tundra Summerand Winter

5. THEMIS/GBO Engineering Peer Review 5 UCB, Oct. 17, 2003 Expected Temperatures Alaska (Poker Flat) Highest max: +35º C (1919) Lowest min: -54º C (1934) Normal max: +23º C (1 Jul) Normal min: -28º C (31 Jan) Southern Canada (Winnipeg) Highest max: +42º C Lowest min: -44º C “Reasonable” Design Range: -50 º to +40 º C

6. THEMIS/GBO Engineering Peer Review 6 UCB, Oct. 17, 2003 Computer Enclosure (CE) Requirements: Must House Support Electronics in Controlled Environment –ASI, GMAG, Computer, Communications, Control, etc. Maintain internal temperature at 20º ± 10º C Operate in external ambient of -50º to +40ºC Provide “dust-free” method of cooling when required External Cable access via “stuffing tube” Provide access door for Hard Drive Hot Swap Provide access for maintenance Ruggedized and shock protection for transportation

7. THEMIS/GBO Engineering Peer Review 7 UCB, Oct. 17, 2003 CE Package Concept “Box within a Box” Internal Rack Mount for Equipment (Doubles as Shipping Case) External Insulated Environmental Enclosure

8. THEMIS/GBO Engineering Peer Review 8 UCB, Oct. 17, 2003 Heating/Cooling Needs Heating Required: Outside temp: -60º C Inside temp: +10º Heat added: 165 W Cooling Required: Outside temp: +50º C Inside temp: +40º Heat removed: 80 W Assumptions: Enclosure dimensions: 34” (h) x 44” (w) x 44” (l) Thermal resistance (R-value): R-12 Internal power dissipation: 47 W

9. THEMIS/GBO Engineering Peer Review 9 UCB, Oct. 17, 2003 Environment Control Design Approach Provide environment inside Computer Enclosure such that commercial hardware can be used for computer, USB hard drives, Telesat gear, etc. All equipment must survive non-operating cold soak in event of power loss Temperature control must allow for warm up of sensitive components prior to re-boot Select “Smart” controller vs Thermostat approach –Programmable with remote access via Iridium –Provides remote control and query –Extended temperature range (-55º to +85ºC) –Low power (battery can operate it for months)

10. THEMIS/GBO Engineering Peer Review 10 UCB, Oct. 17, 2003 CE Temperature Control Temperature Controller AC Line Switches (SSR) From AC Main Breaker AC Power Analog I/O Digital I/O Heater(s) UPS Temperature Sensors Power to Instruments Solid State A/C Power Sequencing after power loss: 1.Heaters, as soon as power restored 2.Instruments (when warm enough) ASICEOutside DC Power

11. THEMIS/GBO Engineering Peer Review 11 UCB, Oct. 17, 2003 Smart Controller Analog I/O Digital I/O Serial I/O Power (12Vdc)

12. THEMIS/GBO Engineering Peer Review 12 UCB, Oct. 17, 2003 Heating / Cooling Silicon Rubber Heat Blankets 400W, 120VAC Solid State Air Conditioner 163W Capacity 120VAC Power

13. THEMIS/GBO Engineering Peer Review 13 UCB, Oct. 17, 2003 Power Control Design Approach Temperature Critical –At low temp. only critical devices powered on –Temperature Controller, Back up modem (Iridium) –At normal temp. System Computer controls device power Temp Controller also Performs Some Power Control –Signals computer shutdown –Graceful shutdown on either power loss or low temp Battery back up –Ride out power outages of 1 hour, or less –Provide power for Temperature Controller at all times –Provide power for critical communications “as much as possible”

14. THEMIS/GBO Engineering Peer Review 14 UCB, Oct. 17, 2003 Instrument Power Control System Computer Serial Port Switch ASI DC Switched AC Outlets UPS GMAG DC Iridium Modem Temperature Controller AC Power Serial I/O Digital I/O Supervisor Channel 2 Supervisor Channel 1 Telesat Modem Control GPS From AC Main Breaker DC Power DC AC Line Switches (SSR) SSR Shutdown Signal All Temp T > T 1 T > T 2 Heater(s)

15. THEMIS/GBO Engineering Peer Review 15 UCB, Oct. 17, 2003 Remote Intervention Two Levels: Typically GBO accessed via Internet –Telesat HSI Under duress, Back up communication via Iridium –2400 bps

16. THEMIS/GBO Engineering Peer Review 16 UCB, Oct. 17, 2003 Remote Intervention System Computer Serial Port SwitchUPSIridium Modem Temperature Controller AC Power Serial I/O Digital I/O Supervisor Channel 2 Supervisor Channel 1 DC Power DC SSR UCB

17. THEMIS/GBO Engineering Peer Review 17 UCB, Oct. 17, 2003 Instrument Data Flow System Computer ASI GMAGTelesat Modem Hot Swap Hard Drive(s) USB Serial I/O 10/100 Base T GPS Internet

18. THEMIS/GBO Engineering Peer Review 18 UCB, Oct. 17, 2003 System Computer Selection Criteria Commercial product Extended temperature range operation Low power (to minimize heat rejection) Peripheral support –Serial, USB, 10BaseT Options Databrick III –Does not meet manufacturer’s specs (0° to 50ºC) –Internal temperatures > 60º operating in 20º lab environment –Reject? Fix? Ventilation could be easily incorporated. Shuttle XPC –No temperature spec –Much higher power (99W vs 32W Databrick) –Higher performance Other –Laptop

19. THEMIS/GBO Engineering Peer Review 19 UCB, Oct. 17, 2003 Databrick Ventilation Mod Fan Air Flow (Open Port)

20. THEMIS/GBO Engineering Peer Review 20 UCB, Oct. 17, 2003 Internal Rack Layout 12RU Rack Mount Case

21. THEMIS/GBO Engineering Peer Review 21 UCB, Oct. 17, 2003 Environmental Enclosure (1/2)

22. THEMIS/GBO Engineering Peer Review 22 UCB, Oct. 17, 2003 Environmental Enclosure (2/2)