Craig S. ClarkAMS-02 Phase II Safety Review1 AMS-02 Thermal Control System (TCS)

Craig S. ClarkAMS-02 Phase II Safety Review2 AMS-02 Thermal Overview  AMS-02 delivered to ISS in orbiter payload bay  Mounted on S3, inboard, zenith Payload Attach Site  Payload nominally dissipates 2400 watts (2800 watts peak)  Will meet all ISS and STS safety requirements  Thermal requirements are defined in SSP (Attached Payload Interface Requirements Document)  Thermal Design Goals  Maintain all experiment components and sub-detectors within specified operating and survival limits (document in AMS-02 Thermal ICD)  Maximize Super Fluid Helium (SFHe) endurance  Optimize sub-detector temperatures to maximize science

Craig S. ClarkAMS-02 Phase II Safety Review3 AMS-02 TCS Hardware  Radiators  Heaters  Thermal Blankets  Loop Heat Pipes (LHPs)  Standard Axial Groove Heat Pipes  2-Phase CO 2 pumped loop  Surface Optical Coatings

Craig S. ClarkAMS-02 Phase II Safety Review4 Radiators  AMS-02 radiators include Main Radiators (Ram and Wake), Tracker Radiators (Ram and Wake), and Zenith Cryocooler Radiators. Main Radiator Wake Main Radiator Ram Wake

Craig S. ClarkAMS-02 Phase II Safety Review5 Main Radiators  Main Radiators dissipate heat from electronics crates.  Ram radiator dissipates up to 525 watts during normal operation, while the Wake Radiator dissipates up to 812 watts.

Craig S. ClarkAMS-02 Phase II Safety Review6 Main Radiators Mounting  Main Radiators are mounted to directly to the crates, which in turn are attached to the USS-02 Lower Brackets (4) Upper Brackets (4) Mid Bracket (4)

Craig S. ClarkAMS-02 Phase II Safety Review7 Main Radiator Construction  Radiators are a sandwich construction with Al face sheets and a ROHACELL® core.  Axial groove heat pipes (aluminum filled with ammonia) are imbedded between face sheets.  Heat pipe flanges maximize thermal contact at crates mounting locations  Chotherm 1671 is used as a thermal interface filler between crates and radiators.  Radiators are painted with SG121FD white paint to optimize heat rejection.

Craig S. ClarkAMS-02 Phase II Safety Review8 AMS-02 Main Radiator Cross-section (flange removed)

Craig S. ClarkAMS-02 Phase II Safety Review9 AMS-02 Main Radiator Heat Pipe Layout RamWake

Craig S. ClarkAMS-02 Phase II Safety Review10 Tracker Radiators  Ram and Wake Tracker Radiators are designed to reject the total heat generated inside the Tracker (144W).  Heat is transported by the Tracker Thermal Control System (TTCS) which will be discussed latter.

Craig S. ClarkAMS-02 Phase II Safety Review11 Tracker Radiators Tracker Radiator (2 x m 2 )

Craig S. ClarkAMS-02 Phase II Safety Review12 Tracker Radiator Construction  Tracker Radiators are a sandwich construction with Al face sheets and a ROHACELL® core.  Heat pipes (aluminum filled with ammonia) are imbedded between face sheets.  TTCS Condensers bolt directly to heat pipe flanges (40mm wide at interface locations, but only 22mm elsewhere).  Chotherm 1671 is used as a thermal interface filler between condensers and radiators.  Outer surface is painted with SG121FD white paint to optimize heat rejection.

Craig S. ClarkAMS-02 Phase II Safety Review13 Tracker Radiator Cross-Section (non-interface section)

Craig S. ClarkAMS-02 Phase II Safety Review14 TTCS Condenser Mounting Interface

Craig S. ClarkAMS-02 Phase II Safety Review15 Tracker Radiator Heat Pipe Layout

Craig S. ClarkAMS-02 Phase II Safety Review16 CARBON FIBER SUPPORT STRUTS TTCS CO 2 CONDENSERS (old design) EMBEDDED HEAT PIPE RADIATOR PANEL

Craig S. ClarkAMS-02 Phase II Safety Review17 Zenith Radiator  The Zenith Radiator (4 separate panels) is design to reject the waste heat generated by the Cryocoolers ( W each).  Heat is transported to each radiator panel via 2 Loop Heat Pipes (LHPs) attached to a single cryocooler.  The LHPs utilize propylene as a working fluid which flows directly through aluminum tubes embedded in the Radiator.  Aluminum tubes in the radiator transition to stainless steel tubes running to the evaporator via a bi-metallic joint.

Craig S. ClarkAMS-02 Phase II Safety Review18 Zenith Radiator Panels

Craig S. ClarkAMS-02 Phase II Safety Review19 Zenith Radiator Construction  Radiators are a sandwich construction with Al face sheets and a ROHACELL® core.  3mm aluminum tubes are brazed to upper face sheet.  Radiator panels are mounted to top of TRD Upper Honeycomb Panel via brackets and glass-fiber pins.  Outer surface is coated with silver-Teflon.  Multi-layer Insulation (MLI) is used between Radiator and TRD.

Craig S. ClarkAMS-02 Phase II Safety Review20 Zenith Radiator Cross-Section Radiator Mounting Radiator Cross-section

Craig S. ClarkAMS-02 Phase II Safety Review21 Multi-Layer Insulation (MLI) Blankets

Craig S. ClarkAMS-02 Phase II Safety Review22 Multi-Layer Insulation (MLI) Blankets  Numerous components of AMS-02 will be covered with MLI blankets  All blankets will meet NASA standards for grounding and venting, and will be constructed according to “MLI for AMS Guidelines” (CTSD- SH-1782)  All blankets will be positively secured.  Typical construction will include multiple layers of aluminized Mylar separated by Dacron scrim. Betacloth will protect exposed surfaces.

Craig S. ClarkAMS-02 Phase II Safety Review23 MLI for AMS Guidelines  Written by Crew and Thermal Systems Division (CTSD-SH-1782, September 30, 2005)  Based on requirements from ISS, STS and MSFC  Electrical Bonding and Grounding  All blankets with surface area greater than 100cm 2 will have at least two (2) grounding assemblies.  Resistance from aluminized surface to ground shall be less than (<) 5,000 Ohms  Resistance from ground to spacecraft structure shall be less than (<) 1 Ohm

Craig S. ClarkAMS-02 Phase II Safety Review24 Heaters  Heaters on AMS-02 are primarily used to:  Warm up components to “switch on” temperature after power outages (including initial turn-on).  Maintain components above minimum operating limits during operation.  Thaw CO 2 (TTCS system) and NH 3 (heat pipes) in case of extended power outages in cold environments.  Manage TTCS operation

Craig S. ClarkAMS-02 Phase II Safety Review25 Heaters (continued)  Most heaters are both thermostatically and computer controlled.  Analyses have been performed to evaluate effect of “run away” heaters.  All safety critical heaters are two-fault tolerant.  No heaters are required to control any hazards.

Craig S. ClarkAMS-02 Phase II Safety Review26 Heat Pipes  Standard axial groove heat pipes are used in several location to help distribute heat:  Main and Tracker radiators have embedded heat pipes mounted directly to heat sources.  Heat pipes are mounted to one of the USS-02 joints to help dissipate heat from the CAB during magnet charging.  Heat pipes are used on the CAB base plates to minimize gradients.  All heat pipes are aluminum filled with high purity ammonia.  Heat pipes are designed to survive freezing/thawing cycles without excessive pressure or rupture.

Craig S. ClarkAMS-02 Phase II Safety Review27 Thermal Optical Coatings  Passive thermal design of AMS-02 include the use of thermal optical coatings.  MLI blankets or plain Betacloth covers are used to improve optics of some surfaces.  Main and Tracker radiators are painted with SG121FD white paint to improve heat rejection.  The Zenith Radiator, along with parts of the Vacuum Case, USS-02, High Voltage Bricks, and CAB are covered with silver-Teflon film to reduce peak temperatures.

Craig S. ClarkAMS-02 Phase II Safety Review28 Cryocooler Cooling  Each of the 4 Cryocoolers dissipate up to 160W of heat in order to remove 4 – 10W of heat from the Cryomagnet system.  Loop Heat Pipes (2 per Cryocooler) are used to transport this heat to the Zenith Radiator where it is rejected via radiation.  The Loop Heat Pipes (LHPs), provided by IberEspacio/Madrid, are similar to those successfully demonstrated as part of COM2PLEX flown on STS-107.  Propylene is used as a working fluid to avoid any freezing. Freezing point of propylene is -185C.

Craig S. ClarkAMS-02 Phase II Safety Review29 Loop Heat Pipe System for 1 Cryocooler Radiator panel Fluid Lines Redundant Evaporators

Craig S. ClarkAMS-02 Phase II Safety Review30 LHP Configuration  Each LHP has a vapor line running to the Zenith Radiator and a liquid line returning.  Lines in and out of the evaporator are stainless steel tube. These tubes transition to aluminum tubes at the edge of the Zenith Radiator via a bi-metallic joint.  “Pumping” pressure is achieved via capillary action in the LHP wick (nickel).

Craig S. ClarkAMS-02 Phase II Safety Review31 LHP Schematic

Craig S. ClarkAMS-02 Phase II Safety Review32 Crycooler to LHP Interface Cryocooler  LHP Evaporators bolt to either side of the Cryocooler heat reject collar.  Indium foil is used as a thermal interface. Evaporator

Craig S. ClarkAMS-02 Phase II Safety Review33 LHP Heaters  Heaters are mounted to the evaporators for LHP startup and to keep Cryocoolers above their minimum storage limits.

Craig S. ClarkAMS-02 Phase II Safety Review34 LHP Bypass Valve  A bypass valve is used to keep Cryocoolers from getting too cold in power outage situations.  A bellows system filled with Argon is used to set the temperature set point of the valve.

Craig S. ClarkAMS-02 Phase II Safety Review35 LHP Bypass Valve Schematic (Argon)

Craig S. ClarkAMS-02 Phase II Safety Review36 CAB Thermal System  The Cryomagnet Avionics Box (CAB) is used to monitor and control the Cryomagnet.  Heat dissipation can vary from 35W to 800W.  Two Loop Heat Pipes (LHPs) will transport heat from the CAB base plate to the outer skin of the Wake Radiator.  Final design details are under review.

Craig S. ClarkAMS-02 Phase II Safety Review37 CAB Thermal System  LHP are similar to Cryocooler LHPs, except that ammonia, rather than propylene will be used as the working fluid.  A bypass valve on the LHP will be used to bypass the radiator if CAB temperature approach lower limits.

Craig S. ClarkAMS-02 Phase II Safety Review38 CAB Thermal System CAB

Craig S. ClarkAMS-02 Phase II Safety Review39 CAB Thermal System  Additional axial groove heat pipes will be attached on the USS between the Upper Trunnion Bridge Beam and the Upper Vacuum Case Interface Joint.

Craig S. ClarkAMS-02 Phase II Safety Review40 TRD Thermal Design  The TRD must be isothermal to +/-3ºC  The TRD and Upper Time Of Flight (UTOF) are enclosed in a common thermal enclosure made of MLI blankets.  The Zenith Radiator is mounted on top of the TRD using low conductivity pins.  Primary TRD interfaces to USS-02 joints are insulated with titanium spacers.

Craig S. ClarkAMS-02 Phase II Safety Review41 TRD Thermal Design Zenith Radiator TRD UTOF

Craig S. ClarkAMS-02 Phase II Safety Review42 TRD Thermal Design  The MLI blanket enclosure is made of 7- layer MLI, except for the portion under the Zenith radiator which is 10-layer.  Heaters are mounted on the TRD M- structure to help minimize gradients and to maintain the detector components (flipper valves) within operating limits.

Craig S. ClarkAMS-02 Phase II Safety Review43 TRD MLI M-structure

Craig S. ClarkAMS-02 Phase II Safety Review44 TRD Gas Thermal Design  The TRD Gas system consists of two parts; the Supply (Box S) and the Circulation (Box C).  Box S includes a high pressure Xenon tank, a high pressure CO 2 tank, a mixing tank, pre- heater volumes, valves, pressure sensors, and associated tubing all mounted on an aluminum base plate.  Box C includes two pumps, monitoring tubes and valves.  Both Box S and Box C are enclosed in an MLI blanket.

Craig S. ClarkAMS-02 Phase II Safety Review45 TRD Gas Thermal Design Xe Tank CO 2 Tank Circulation Box (Box C) Valve blocks

Craig S. ClarkAMS-02 Phase II Safety Review46 TRD Gas Tank Heaters  Active heating is required to keep both the Xenon and CO 2 tanks above their respective saturation temperatures.  This is required in order to measure the amount of gas left in the tanks.  Extremely long time constants preclude short term heating only.  The Xenon tank should stay above 20ºC  The CO 2 tank should stay above 34ºC

Craig S. ClarkAMS-02 Phase II Safety Review47 TRD Gas Tank Heaters  Kapton foil heaters are glued to the surface of the composite over-wrapped stainless steel tanks.  On each tank there are two strings of eight heater patches (one per power feed).  Four thermostats in series are used for each string to protect against over heating the tanks.  Each tank is wrapped with MLI.

Craig S. ClarkAMS-02 Phase II Safety Review48 TRD Gas Tank Heaters heaters thermostats

Craig S. ClarkAMS-02 Phase II Safety Review49 TRD Gas Pre-Heaters  A Pre-heater is used to warm small volumes of Xenon and CO 2 making transfer to the mixing tank more controlled.  Heater is computer controlled using temperature sensors on heater plate.  Heater will only be activated for brief periods (<15 minutes per day)  4 thermostats in series protects against over heating.

Craig S. ClarkAMS-02 Phase II Safety Review50 TRD Gas Valve Blocks  The are 5 groups of valves in Box S mounted together with support brackets.  Brackets are isolated from the base plate with G10 spacers.  Each block of valves is individually wrapped with MLI.  Resistive heaters are mounted on each valve support bracket to maintain valves above operating limits.  A single thermostat is used to control each valve block heater (Except for the tower valve which has 4 in series)  Two additional thermostats in series are mounted on the base plate to control power to all valve heaters.

Craig S. ClarkAMS-02 Phase II Safety Review51 TRD Gas Box C  Box C pumps the low pressure gas mixture from Box S to the TRD detector.  The two pumps are enclosed in a pressurized canister.  Kapton foil heaters are mounted on this canister to maintain the pumps above their operating limits.  Resistive heaters are mounted on a block of valves to maintain valve temperature limits.

Craig S. ClarkAMS-02 Phase II Safety Review52 TRD Gas Box C

Craig S. ClarkAMS-02 Phase II Safety Review53 TRD Gas Box C  Both the canister heater and the valve block heater are each controlled with a single thermostat.  The two additional thermostats on the base plate cut heater power in hot environments.

Craig S. ClarkAMS-02 Phase II Safety Review54 TRD Gas 28V Heater Schematic A c c c c c c c c Xe vessel <20W T Xe vessel <20W T CO2 vessel <24W T CO2 vessel <24W T Preheater <15W <10W T Valve Tower <10W tower<10W T Preheater <15W <<<10W<10W T Valve Tower <10W tower<10W T B A B c c c c c c c c UPDATE

Craig S. ClarkAMS-02 Phase II Safety Review55 TRD Gas 120V Heater Schematic 4 valve unit 11W T 2 valvefilter 7W T 2 Valve GP50 5W C-tank 10W T 4C-valves 4W T 4 valve unit 11W T 2 valvefilter 7W T 2 Valve GP50 5W T C-tank 10W T 4C-valves 4W T ABAB ABAB T UPDATE

Craig S. ClarkAMS-02 Phase II Safety Review56 Thermal Design of other AMS-02 Subsystems  Extensive work has also been performed on the thermal design of other AMS-02 Detectors and subsystems not described here  Designs include MLI, thermal fillers, thermal optical coatings, etc.  None of these designs affect any pressure systems or other safety critical components.