1. PACS IQR ESTEC 13 January 2005 Mech Qual Status 1 PACS IQR Mechanical Qualification Status and Plans for PFM Reinhard Katterloher R. Graue, D. Kampf, R. Hofferbert, M. v.Berg

2. PACS IQR ESTEC 13 January 2005 Mech Qual Status 2 Overview Mechanical Qualification Status and Plans for PFM FPU structure - mirrors - baffles - black paint - impact of additional heaters and flashers Filter wheels Calibration sources Grating assembly Chopper WE units Delta Cryovibration Qualification Matrix (PhFPU presented by LR) (Ge:Ga arrays presented by JS)

3. PACS IQR ESTEC 13 January 2005 Mech Qual Status 3 FPU structure, mirrors, baffles: main data Total mass allocation in IID-A for PACS is 140 kg, mass requirement is met (margin 13.2 kg), FPU CQM has 74.1 kg Eigenmodes of complete FPU above 100 Hz, requirement is met for all axes (x,y,z = 188,122,104 Hz) verified by cryogenic vibration of FPU STM Mirror environmental tests OK, Au coating no concern (initial NCR closed), optical alignment check/stability on FPU CQM not done, after FPU STM cryo-vibration dummies mechanically checked Baffles structural OK Upgrades for PFM: none, except - additional baffles required to reduce stray light inside the FPU spectrometer section (see presentation by AP), - modification of detector baffles to carry flashers for curing

4. PACS IQR ESTEC 13 January 2005 Mech Qual Status 4 PACS FPU Architecture – 6 Stand Alone Modular Substructures Top Optics with Chopper (C.Z.) and 2 Calibration Sources Image Slicer Bolometer Optics with Filter Wheel PhFPU with 0.3 K Cryo-Cooler (CEA) Collimator with Grating Assembly (CSL) Spectrometer with Ge:Ga – Photoconductor Arrays (MPE), Filter Wheels, Distribution Boards (Cold Electronics) Level 0 Thermal Links - Thermal Feed Throughs (1.7 K)

5. PACS IQR ESTEC 13 January 2005 Mech Qual Status 5 FPU Analyses All FPU Analyses Performed

6. PACS IQR ESTEC 13 January 2005 Mech Qual Status 6 PACS FPU Structural Verification Tests completed Similarity CQM and STM were manufactured parallel with the same drawings out of the same lot Qualification Tests STM vibration tests Conclusion: FPFPU Housing is structurally qualified Tests completed LHe-VibrationVibration res.src.

7. PACS IQR ESTEC 13 January 2005 Mech Qual Status 7 FPU Cryovibration Qualification Breakdown  All Items Qualified # means remaining problems to be solved resp. delta-vibration to be done

8. PACS IQR ESTEC 13 January 2005 Mech Qual Status 8 Structural Analyses - Status  Evaluation of ambient (STM) and cold vibration tests (Cryo STM)  FEM calibration  Load analyses with calibrated model (cryo-vibration test)  Strength analyses for FPU metallic and CFRP components  Cryogenic material properties analyses  CoG, MoI analyses  Displacement, distortion, deformation analyses All Documentation released

9. PACS IQR ESTEC 13 January 2005 Mech Qual Status 9 Approach to FPU PFM Cryovibration Protection of sensitive subsystems during acceptance vibration, random loads not to exceed 10 g rms Dynamic analysis of PACS on CSL shaker performed by ESA - response of red and blue bolometer FPA and their relation with a point on the outside of PhFPU housing determined - mounting of a triplet-accelerometer foreseen Frequencies and Q-values are to be checked during warm FPU- STM vibration at MPE Notching at the PACS feet during PFM cryovibration at CSL

10. PACS IQR ESTEC 13 January 2005 Mech Qual Status 10 FPU PFM Test Plan and PFM MAIV Status Subsystem level (FW, CS, DBs, Substructures) –Mechanical and Thermal Test program as given in Test Plan (similar to CQM) –Outbaking at 80 °C (minimum) –Functional test program as given in test plan (similar to CQM) –Substructures alignment verification -Cryogenic stability tests (tbc) System level (FPU) –Cryovibration test (KT support at CSL) –Functional test (KT support at MPE)  MAIV Status  Metallic items manufactured  CFRP items manufactured and static load tested  Calibration Sources manufactured and partly assembled  FW assemblies manufactured, pre-tested on motor drive level, partly assembled  Pre-assembly (fit check in progress)

11. PACS IQR ESTEC 13 January 2005 Mech Qual Status 11 FPU Black Paint: main data of KT72 PACS-RFW-0003 agreed: out-gassing requirements met Optical performance: satisfying Adhesion on Al surfaces: satisfying Particle release below 100ppm, improvement advised: impact of pre-vibration under investigation, additional cryogenic vibration planned in February 2005, CEA: concerned about particle fall-out onto bolometer FPAs, MPE: protection of grating/FW bearings might be advisable Upgrade for PFM: very likely none

12. PACS IQR ESTEC 13 January 2005 Mech Qual Status 12 Impact of additional Heaters and Flashers 2 heater resistors on the red detector array: mass increase 0.2% > no impact on mechanical behaviour 2 flashers mounted at the end of each detector array baffle: mass increase few % > no impact on mechanical behaviour Additional wiring inside the FPU required (mass negligible) Re-routing on both distribution boards required (redesign) mass increase on one board due to a new connector > no impact on structural properties expected For detector curing PACS needs to implement additional heaters and flashers in the FPU. The impact on the mechanical properties of both detector arrays (Upgrade for PFM) is estimated as follows (detailed design in progress):

13. PACS IQR ESTEC 13 January 2005 Mech Qual Status 13 FPU Filter Wheels Photometer FW : OK (initial blocking by a screw resolved) Spectrometer FW problematic: - during CQM ILT blocked at 4K - during warm-up partial movement at 90K Currently investigations on CQM wheel at KT in progress: - at 77K higher friction observed - ball bearing sensitive to abrasion during warm vibration? - baffle removed for better inspection of drive - blocking of rotor on one Hall sensor found - new cryogenic verification test planned Upgrade for PFM: revised tolerance of bearing support

14. PACS IQR ESTEC 13 January 2005 Mech Qual Status 14 Filter Wheel Assembly  Required Torque to Leave the Filter Position : 0.5 Ncm  Maximum Motor Torque Performance : 4.2 Ncm.  Motor & Position Indicator are in Powerless Dormitory Mode between Operations  Position Locking Principle: Contact-less Magnetic System  No Launch Lock Mechanism Required

15. PACS IQR ESTEC 13 January 2005 Mech Qual Status 15 FPU Calibration Sources Cryogenic qualification on EM during FPU STM vibration Upgrade for PFM: None

16. PACS IQR ESTEC 13 January 2005 Mech Qual Status 16 Calibration Source Lay-out Wavelength/scattering optimised surfaces 2 identical Calibration Sources mounted in FPU Operation at 4 K, Emitter temperature 50 - 100 K  Sphere (inner diameter 51 mm)  Redundant Combined Sensor and Emitter (PT 500)  Circular aperture (diameter 12 mm) with Si lens put in front of aperture  Surface with Lambertian stray light behaviour and high reflectivity (> 0.992)  Emitter suspension:  4 filigree GFRP struts with 24 x 0.25 x 0.25 mm³  Titanium coated for 4 wire connection to the source

17. PACS IQR ESTEC 13 January 2005 Mech Qual Status 17 FPU Grating Assembly Cryogenic vibration qualification on EM plus additional qualification (vibration, cryo-cycling) on CQM incl. launch lock mechanism at subsystem level: OK Movement quality of grating CQM: OK Functionality of launch lock mechanism of CQM: OK Upgrades for PFM: - modified routing of internal harness needed - Inductosyn transformer needs to be mounted inside the grating assembly (for CQM currently on FPU outside) - Fixation of grating plate on axis has to be improved - cleanliness before delivery for integration with FPU to be improved and protection cover advised

18. PACS IQR ESTEC 13 January 2005 Mech Qual Status 18 FPU Chopper Development performed as specified in IHDR presentation (environmental tests, lifetime test …) Minor deviations for CQM: - envelope violation of cable housing (solved) - cryovibration done on subunit level at 77K only (agreed) (no LHe vibration with CQM performed) Upgrades for PFM: - no deviation from MPIA/ZEISS development plan foreseen - Au coating of mirror very likely to be changed (thickness and coating process to be improved)

19. PACS IQR ESTEC 13 January 2005 Mech Qual Status 19 WE Units AVM / STM WE Unit testing - No structural tests required in general - STM BOLC: Vibration tests done : validation of design > Problem with displacement of boards - STM BOLC PSU sub-unit vibrational tested : OK CQM / AVM ILT - No structural test on WE Units foreseen PFM (QM) WE Units - Full environ. test program agreed before FM delivery to MPE - First structural results for QM SPU available (> some NCRs) - New mechanical design for DPU CFM / PFM, will be fully tested Mass margin for PACS is 13.2 kg in total (DECMEC mass uncertainty not critical in this respect)

20. PACS IQR ESTEC 13 January 2005 Mech Qual Status 20 Delta Cryo-vibration Qualification Matrix of FPU Subunits FPU SubunitDelta cryo- vibration qualification Scheduled PhFPU (bolom.+cooler) Done (upgraded STM) October 04 Ge:Ga-array internal cooling link with I/Fs Open (STM housing + FM components) March 05 Ge:Ga-array suspension strut electr. insulation Open (STM housing + FM components) March 05 Grating assembly CQM incl. L Lock Done (CQM) February 04 Unchanged Development Concept & Model Philosophy since IHDR Approval of PACS-RFW-0007 expected !