AMS Tracker Thermal Control System (TTCS)

1. AMS Tracker Thermal Control System (TTCS) Phase II Safety Presentation SRII meeting, 21 May 2007, Houston Johannes van Es/NLR

2. Contents • TTCS Objective • TTCS System Overview • TTCS Components • TTCS operational results

3. TTCS System Overview 144 Watts

4. TTCS Objective • Provide accurate temperature control of AMS Tracker front-end electronics • Keep heat away from the Cryogenic System and Magnet

5. TTCS Overview • Two independent redundant CO2 two-phase pumped loops • Primary loop • TTCB Box on Port side • Condenser at Wake and RAM radiator (also port side) • Secondary Loop • TTCB Box on Starboard side • Condenser at Wake and RAM radiator (also starboard side) • TTCE Tracker Thermal Control Electronics located at the wake radiator bottom next to PDS

6. Tracker radiators TTCS Condensers are attached to the Tracker radiators Tracker TTCS box envelopes (locations)

9. Box components • All components except the evaporator and the condenser are located in the TTCS-box • one primary box (port side) • one secondary box (starboard side) • Containing • Pumps (2x) • Accumulator with Peltier heat exchanger • Heat Exchanger with start-up heaters • Absolute pressure sensors (2x) • Differential pressure sensors (2x) • Cold orbit heater (1 unit) • Pre-heaters (2x) • Thermal switches (20x) • Pt1000 temperature sensors (30x) • Dallas temperature sensors (22x)

10. Tracker Thermal Control System Evaporator (overview) 192 Hybrids each producing 0.75 Watts of heat (144 W total)

11. Tracker Thermal Control System Evaporator (overview)

12. Tracker Thermal Control System Evaporator tubing upper inner and outer ring Connection to transport tubing

13. Tracker Thermal Control System Welding close to TTCS boxes TTCS Boxes

14. TTCS Primary Box location (wake port side) weld locations indocated with arrows

15. Tracker Thermal Control System TTCS Condenser locations

16. TTCS Primary loop Wake Condenser (WAKE port side) • Each system has two condensers one on Wake side and one on RAM side

17. STARBOARD side RAM PORT side WAKE Primary loop TTCS tubing on port side

18. STARBOARD side RAM PORT side WAKE Secondary loop TTCS tubing on starboard side

19. TTCS System summary box components Each independent loop includes the following components the loop box: • 2 redundant pumps • 1 Accumulator to • accommodate liquid in case of two-phase operation and to allow for temperature-volume changes • control the evaporation temperature in the evaporator by control heaters, Peltier elements and emergency heaters • Heat Exchanger to use the evaporator heat to pre-heat the subcooled CO2 fluid (saves power) • 2 Pre-heaters to heat both evaporator branches to Tsaturation

20. TTCS System summary box components • Absolute pressure sensors to monitor the pressure • Differential pressure sensors to monitor the mass flow • Cold orbit heater used to increase energy content of the CO2 two-phase flow. To avoid too low temperatures in cold orbit condition operation • Start-up heater to heat the liquid flow to the evaporator from -40C to -20C to keep front-end electronics in their temperature window

21. TTCS Box accumulator Abs. P-sensor Cold orbit heater Heat exchanger Swagelok weld couplings Diff. P-sensor

22. TTCS Box accumulator Abs. P-sensor Cold orbit heater Heat exchanger Diff. P-sensor Swagelok weld couplings Cover with ext. connectors

23. TTCS Box Pumps Cold orbit heater Pump Electronics box

24. Pump Pump is an adapted Martian Exploration rover pump by PDT • Centrifugal pump • Successful CDR in September 2006 Pump Controller EM Pump

25. Accumulator Two-phase accumulator • Heat pipe to heat the accumulator in the centre of the accumulator • Peltiers to cool the accumulator at the mantle the Peltier cold side connected to the liquid line from the condensers

26. Accumulator liquid inlet pipe with mesh HP cross section

27. Accumulator • Mesh Design • Spoke design to transport the liquid to the HP • Wick Design Fan Mesh to keep the CO2 around the liquid inlet to supply the CO2-loop with liquid Spoke mesh design fan mesh design and liquid inlet HP cross section Spoke and Fan mesh design Fan mesh detail

28. Heat exchanger Assembly Heat Exchanger QM/FM

29. HX QM/FM Assembly • Heat Exchanger exists of: • 36 stacked heat exchanger plates (Inconel 625) • Two container parts (Inconel 625) with machined tube ends • 2 Diff. Pressure Sensor at ones side • 4 connections to the loop at the other side • 2 heater wires at the mantle • 2 brackets to connect to the bottom plate • 2 clips to connect HX to the brackets • 6 Thermal Switches (integrated later) to avoid overheating the TTCS system

30. HX QM/FM Assembly

31. Pre-heater

32. Cold-orbit heater

33. TTCS Breadboard Testing Results