1. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 1 Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas RAMS ANALYSIS PM#03 Torino - April 5 th - 6 th, 2006

2. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 2 RAM aspects The RAM activity performed in the present phase is dedicated to the system requirement allocation process in order to provide inputs for the equipment specifications; it covers the following topics: - Refinement of the Antenna Reliability Block Diagram (RBD) according to all the available design information - Preliminary evaluation of the antenna equipment failure rate for which consistent design data are defined - Modification of the predicted equipment failure rates in order to satisfy the system level objective (MTBF  3 years).

3. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 3 RELIABILITY BLOCK DIAGRAM The RBD is adequately defined for all the Antenna sections, except for: HVAC = The current modelization does not include any redundancy; however, considering the available MTTF figures in the technical literature (for not redundant HVAC) and the stringent Antenna MTBF requirement, it is supposed that some redundant units could be necessary to satisfy the preliminary allocated figure (MTTF  125000 h). UPS & Power Supply = design under definition; the available information does not allow a preliminary modelization and evaluation of the failure rates of the involved units. The preliminary allocation process leads to MTTF  40000 h. Smoke detectors and safety switches = The quantity of units and associated configuration under definition Metrology system = The units typologies and quantity are defined; the redundancy logic (if any) to be identified as result of the engineering analyses (thermal, structural, error budget, etc.)

4. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 4 PRELIMINARY EVALUATION OF EQUIPMENT FAILURE RATES This step of the RAM analysis is important to quantify the contribution of each unit to the overall antenna MTBF figure; the assessment takes into account all the available engineering information. The obtained figures constitute only the starting point for the apportionment process; they do not represent the Reliability performance of the antenna units (to be provided by suppliers). The table below lists the result of the prediction (at unit level) performed by the consortium. EQUIPMENTCOMPONENTActive failure rate (fit=1.0 E-9 h -1 Stand by factorStand by failure rate (fit=1.0 E-9 h -1 Sources AZIMUT STOW PINMotor Gear mechanism 13580.5 189.9 1% (for bearing) and 10% for winding) 1% 143.476 1.899 MIL-HDBK-217F + Notice 2 NPRD-95 ADJUSTERThe main contributor is the spring 476.61%4.766NPRD-95 ELEVATION ROLLER BEARING 430.381%4.304NPRD-95

5. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 5 PRELIMINARY EVALUATION OF EQUIPMENT FAILURE RATES (cont’) EQUIPMENTCOMPONENTActive failure rate (fit=1.0 E-9 h -1 Stand by factorStand by failure rate (fit=1.0 E-9 h -1 Sources AZIMUT HARD STOP Bumper Mechanism 1136.4 800 1% 11.36 8 NPRD-95 ESA-PSS-01-302 ELEVATION STOW PINS Motor Gear mechanism 13580.5 189.9 1% (for bearing) and 10% for winding) 1% 143.476 1.899 MIL-HDBK-217F + Notice 2 NPRD-95 ELEVATION HARD STOP Bumper1136.41%11.36NPRD-95 ELEVATION LIMIT SWITCH Limit switch1924 10%192.4MIL-HDBK-217F + Notice 2 AZIMUTH ROLLER BEARING 430.381%4.304NPRD-95 AZIMUTH CABLE WRAP 73.428 1%0.73428NPRD-95 AZIMUTH LIMIT SWITCH Limit switch1924 10%192.4MIL-HDBK-217F + Notice 2

6. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 6 PRELIMINARY EVALUATION OF EQUIPMENT FAILURE RATES (Cont’) EQUIPMENTCOMPONENTActive failure rate (fit=1.0 E-9 h -1 Stand by factorStand by failure rate (fit=1.0 E-9 h -1 Sources EMERGENCY STOP137810%137.8MIL-HDBK-217F + Notice 2 SUBREFLECTOR MECHANISM – LINEAR ACTUATOR Motor Gear mechanism 13580.5 189.9 1% (for bearing) and 10% for winding) 1% 143.476 1.899 MIL-HDBK-217F + Notice 2 NPRD-95 FEED SHUTTERGear Box motorized with electrical motor Inductive switch 13770.4 2500 1% (for bearing & mechanism) and 10% for winding 10% 145.375 250 MIL-HDBK-217F + Notice 2 & NPRD-95 Data from AAS-F MTBF=400.000 h ELEVATION DRIVE SYSTEM Drive arc Drive amplifier AXV 25554 Insulation transformer Main filter Filter between drive & motor Braking resistor 548.8 11000 617.4 1000 400 4813.31 10% 54.88 1100 61.74 100 40 481.331 MIL-HDBK-217F + Notice 2 Engineering judgement MIL-HDBK-217F + Notice 2 Engineering judgement MIL-HDBK-217F + Notice 2

7. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 7 PRELIMINARY EVALUATION OF EQUIPMENT FAILURE RATES (Cont’) EQUIPMENTCOMPONENTActive failure rate (fit=1.0 E-9 h -1 Stand by factorStand by failure rate (fit=1.0 E-9 h -1 Sources ELEVATION CABLE WRAP 73.428 1%0.73428NPRD-95 ELEVATION BRAKE SYSTEM Spring operated calliper Oil pump 1136.4 TBD 1%11.36NPRD-95 AZIMUTH BRAKE SYSTEM Spring operated calliper Oil pump 1136.4 TBD 1%11.36NPRD-95 ELEVATION ENCODER SYSTEM Encoder Hall effect sensor 600 2500 10% 60 250 Engineering judgement MTTF>400000 h (from a manufacturer data sheet): preliminary figure METROLOGY SYSTEM Tiltmeter Thermal sensor 142.86 5.89 10% 14.286 0.589 MTTF>7x10 6 h (from available manufacturer data) MIL-HDBK-217F + Notice 2

8. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 8 PRELIMINARY EVALUATION OF EQUIPMENT FAILURE RATES (Cont’) EQUIPMENTCOMPONENTActive failure rate (fit=1.0 E-9 h -1 Stand by factorStand by failure rate (fit=1.0 E-9 h -1 Sources AZIMUTH DRIVE SYSTEM Drive segment fork Drive amplifier AXV 25554 Filter between drive & motor Braking resistor 548.8 11000 400 4813.31 10% 54.88 1100 40 481.331 MIL-HDBK-217F + Notice 2 Engineering judgement MIL-HDBK-217F + Notice 2 AZIMUTH ENCODER SYSTEM Encoder Hall effect sensor 600 2500 10% 60 250 Engineering judgement MTTF>400000 h (from a manufacturer data sheet): preliminary figure SMOKE DETECTOR 500010%500Engineering judgement

9. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 9 PRELIMINARY EVALUATION OF EQUIPMENT FAILURE RATES (Cont’) EQUIPMENTCOMPONENTActive failure rate (fit=1.0 E-9 h -1 Stand by factorStand by failure rate (fit=1.0 E-9 h -1 Sources ANTENNA CONTROL UNIT (VME crate) MVME5100 Motorola CPU board Dual CAN PMC Tews expansion board TVME220 Tews carrier board Octal RS485 serial communication board TIP501 Tews 16 channels analog input board OPTO22 24 channels digital I/O board KNIEL CP24.4 (24V) power supply unit IK320 Heidenhein Encoder signal conditioning board 5249.1 5000 2617.8 3246.8 3310 1500 6000 5000 10% 524.91 500 261.78 324.68 33.1 150 600 500 MTTF=190509 h (from available manufacturer data) Engineering judgement MTTF=382000 h (from available manufacturer data) MTTF=308000 h (from available manufacturer data) MTTF=302112 h (from available manufacturer data) Engineering judgement

10. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 10 PRELIMINARY EVALUATION OF EQUIPMENT FAILURE RATES (Cont’) EQUIPMENTCOMPONENTActive failure rate (fit=1.0 E-9 h -1 Stand by factorStand by failure rate (fit=1.0 E-9 h -1 Sources HVAC SYSTEM Scroll compressor Cu & Al condenser battery with R407 C coolin liquid Copper evaporator Thermostatic expansion valve Cu & Al free cooling battery Membrane expansion tank Axial fan with variable speed Solenoid valve TBD N/A TBD N/A TBD

11. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 11 PRELIMINARY EVALUATION OF EQUIPMENT FAILURE RATES (Cont’) EQUIPMENTCOMPONENTActive failure rate (fit=1.0 E-9 h -1 Stand by factorStand by failure rate (fit=1.0 E-9 h -1 Sources HVAC SYSTEM (CONT’) Three way modulating valve Circulation pump Filter Liquid indicator Flow switch Pressure switch Electrical cabinet, I/F with ACU TBD

12. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 12 RAM INPUTS FOR ANTENNA UNITS SPECIFICATIONS The preliminary failure rates obtained in the RAM assessment by the consortium, have been modified (reduced) in order to guarantee the system level requirement. The definition of these figures (that represent the reliability requirement at unit level) takes into account: - The expected practical limits for each unit typology (electronic, mechanical, electrical, etc.) in the ALMA operative environment. This is based mainly on engineering considerations. - The possibility to implement a complete or partial redundant configuration at unit level - The expected duty cycle (less than 100%) that allows to improve the effective unit failure rate for ALMA purposes. The table below lists the selected reference units MTTF (= 1/failure rate, assuming the exponential law for the time to failure of the units):

13. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 13 MTTF REQUIREMENTS N. Item act (fit) MTBF (h) 1 Linear Actuator1550645161 2 Elevation Drive Arc2005000000 3 Elevation Drive Amplifier2200454545 4 Drive Insulation Transformer1258000000 5 Drive Main Filter2050000000 6 Drive Filter Between Drive & Motors2050000000 7 Drive braking Resistor1258000000 8 Elevation Calliper2005000000 9 Elevation Brake Oil Pump8001250000

14. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 14 MTTF REQUIREMENTS (cont’) N.Item act (fit) MTBF (h) 10 Azimuth Calliper2005000000 11 Azimuth Brake Oil Pump8001250000 12 Elevation Encoder8001250000 13 Metrology: Tilt meter10010000000 14 Metrology: Thermal sensor3,333E+08 15 Az Drive segment1506666667 16 Az Drive Amplifier2200454545 17 ACU VME crate10000100000 18 Azimuth Encoder8001250000

15. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 15 MTTF REQUIREMENTS (cont’) N.Item act (fit) MTBF (h) 19 HVAC8000125000 20 Smoke detectors4552197802 21 Elevation Roller Bearing1506666667 22 Elevation Stow Pin1111090009 23 Elevation Hard Stop1428700280 24 Azimuth Three roller bearing1506666667 25 Elevation Limit Switch2005000000 26 Azimuth Stow Pin1111090009 27 Azimuth Hard Stop1428700280 28 Azimuth Cable Wrap73,42813618783

16. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 16 MTTF REQUIREMENTS (cont’) N.Item act (fit) MTBF (h) 29 Azimuth Limit Switch2005000000 30 Safety Switches5002000000 31 Power Supply + UPS2500040000 32 Emergency Stop Button8012500000 33 Elevation Cable Wrap73,42813618783 34 Feed Shutter Gear Box + Motor1550645161 35 Feed Shutter Inductive Switch2504000000 36 Adjuster4002500000

17. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 17 SAFETY ACTIVITY  Hazard Analysis Preliminary Hazard trees, Hazard Matrix and Hazard list have been developed:  For each Hazard a preliminary list of possible causes has been developed  9 Hazards in total.  29 possible causes

18. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 18 Hazard Report Number Hazard Report Title Causes ALMA-01Collision of operator while working in the Antenna 1.Collision of operator while working in narrow environment (Base or receiver cabin) 2.Collision of operator due to Antenna moving parts ALMA-02Contamination of receiver cabin, base or any Antenna environment 1.Contamination due to battery leakage 2.Contamination due to environmental control fluid leakage

19. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 19 Hazard Report Number Hazard Report Title Causes ALMA-03Structural failure of Antenna1.Inadequate structural strength 2.Manufacturing defect, flaw or improper assembly 3.Fatigue 4.Creep 5.Vibration 6.Corrosion 7.Dissimilar metal causing corrosion 8.Thermal distortion ALMA-04Operator injury/death due to electrical shock 1.Contact with energized parts of operating electrical equipment 2.Electrostatic discharge 3.Lightning

20. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 20 Hazard Report Number Hazard Report Title Causes ALMA-5Explosion1.Explosion of pressure components 2.Battery explosion ALMA-06Operator injury due to extremes temperatures 1.Contact with cryogenic system 2.Contact with electrical hot equipment 3.Contact with sun heated structural surfaces ALMA-07Fire, ignition of flammable materials 1. Use of flammable materials 2. Ignition sources

21. Reproduction interdite © ALMA EUROPEAN CONSORTIUM Reproduction forbidden Design, Manufacture, Transport and Integration in Chile of ALMA Antennas Page 21 Hazard Report Number Hazard Report Title Number of causes ALMA-08Operator injury1. Pinching of operator appendix due to Antenna moving parts 2. Operator injury due to broken frangible materials 3. Operator injury due to sharp edges 4. Personnel exposed to excessive noise ALMA-09Loss of Antenna control1. Loss/degradation of power supply 2. Failure of Antenna Control Unit 3. Failure of rotating equipment