WPT-S

1. PWI/WPT (Wire Probe anTenna) WPT-S 15m x 2 MEFISTO 15m x 2 [WPT: Team members] Lead Co-I Y. Kasaba (JAXA) Manufacturer NIPPI [PWI] K. Ishisaka, T. Okada (Toyama Pref. U.) A. Matsuoka, T. Abe (JAXA) L. Blomberg (KTH [MEFISTO]) M. Moncuquet (LESIA [SORBET]) [System] K. Komatsu, Y. Morita (JAXA) With the aide of PWI team members & MMO system members MEFISTO-S WPT-S WPT-S MEFISTO-S

2. PWI/WPT (Wire Probe anTenna) Mechanical – past Design 　*Vertical 　*Latch release: wire cutter with Pyro 　*After the release: Stopped by the tension between “wire” & “spring in Holder” 　*Plane-gear mechanism

3. (1) Progress from the last design meeting (Sep. 2005) <<<Mechanical>>> *Overall Design: 3 changes - “Horizontal”: reduce the sun-lit part - Latch:released by “motor, without Pyro” - Addition of “spacer” *Mass reduction study: failed O Plane-gear 600g at this moment ? Worm-gear 630g (structure: -15g, gear： -30g, motor: +75g） A/I: - “Light-weight motor” – Torque requirement is Margine = x4 at Retraction in full-extension [Heritage of MAST design] - Reduction of the required torque: *reduction of torque margine? *reduction of spin rate at the full extension? [depending on initial centrifugal force & attitude stability of the spacecraft] *refine of the requested retraction

4. (1) Progress from the last design meeting (Sep. 2005) <<<Mechanica>>> *Test of the Latch mechanism Static load test: OK for “<53G” A/I：　Dynamic load test (based on the issued tentative environment condition) *Wire: Thermal-shock test – No problem A/I： Strength test @ high temperature Establishment of the contact to the sphere Def. of I/F & Installation to the spacectaft Load direction

5. (1) Progress from the last design meeting (Sep. 2005) <<<Thermal>>> *MTM It is not updated after September 2005 A/I: Update of MTM > Definition of I/F to Side/Lower panels > Update of I-ICD & CDD <<<Electrical>>> *Harness/Connector: Trough-hole at the lower deck Connector & harness at the “top-panel” of WPT-S A/I： Def. of “Stepping motor” (incl. torque margine, mass, EMC) <DC motor requires safety measure for over-current.> <<<Material [with MEFISTO]>>> *Surface sample: Photo-electron / 2nd electron yield will be measured. A/I: next week – Photo-electron distribution Future – Amount of Photo-electron / 2nd electron yield <<<Numerical evaluation>>> *Attitude analyses: Preliminary analyses is “OK”. A/I: incl. Despun & non-symmetric extension

6. (3) Development plan in 2006 <Mechanical> Establishment of “key parts design” Finish of the Environment test of BBM & Materials Updating (& reduction) of Mass <Termal> Update of MTM, Establishment of the wire strength in High-T <Elec.> Establishment (& reduction) of Monitor items [= establishment of MAST/WPT-E] Establishment of the Motor power production from 50V-bus [= establishment of MAST/WPT-E] Establishment of the control scheme at the extension [= establishment of basic design of software on MDP] (5) Major request to System / Other subsystems & payloads <Mechanical> Definition of I/F Definition of safety requirement (torque margin, strength margin) Purging for MoS2??? <System> Spin axis direction, Reduction of surface charging Appendix. Current Resources <Mass> (without margin) *Assigned mass 545g (without margin) *Current design 600g

7. “+-4mm move” might be expected.