STEIN Mechanical Systems

1. STEIN Mechanical Systems David Glaser Space Science Laboratory Space Physics Research Group UC Berkeley STEIN Review UCB/SSL Nov 10, 2011

2. Overview • Mechanical Requirements • Instrument Overview • Mechanical Subsystems • Progress to Date • Concluding Remarks STEIN Review UCB/SSL Nov 10, 2011

3. Mechanical Requirements • Large FOV/Geometric Factor • Little scattered light reaching detector • 4 mm spaced HV deflectors spaced at least 2 mm from structure • Detector 10 mm behind electrostatic deflectors • Light tight behind detector • Retractable mechanical attenuator that • Reduces particle flux by 99% • Requires no power except when opening or closing • Produces no large magnetic fields • Instrument must fit into the CINEMA chassis • Instrument must withstand launch vibration levels STEIN Review UCB/SSL Nov 10, 2011

4. Instrument Overview • Collimator FOV 60°x 40° • ± 2000 V Field Separates Electrons, Ions, and Neutrals to ~20 keV • Particle Attenuator • (Blocks 99% of Particles) STEIN Review UCB/SSL Nov 10, 2011

5. Mechanical Subsystems • Housing • Baffles/Collimator • Electrostatic Deflectors • Attenuator • Electronics Mounting STEIN Review UCB/SSL Nov 10, 2011

6. STEIN Housing STEIN Review UCB/SSL Nov 10, 2011

7. STEIN Housing • Photoetched BeCu • Ebonol C Blackened Surface • Attached with Epoxy STEIN Review UCB/SSL Nov 10, 2011

8. Baffles 60°x 40° Aperture STEIN Review UCB/SSL Nov 10, 2011

9. Electrostatic Deflectors Leaves chosen instead of flat surface minimize scattered electrons on detector STEIN Review UCB/SSL Nov 10, 2011

10. Electrostatic Deflectors 4 mm Separation Between High Voltage Surfaces STEIN Review UCB/SSL Nov 10, 2011

11. STEIN Attenuator • Mechanism Heritage from THEMIS Mission • Nanomuscles – Shape Memory Alloy Actuators • Bi-Stable Overcenter Mechanism STEIN Review UCB/SSL Nov 10, 2011

12. STEIN Attenuator • SMA Actuator • Nanomuscle modified for Structural Soundness • No significant ferromagnetic parts • Each actuation: ~2.5W for 0.15 sec • Life test for >70,000 cycles STEIN Review UCB/SSL Nov 10, 2011

13. STEIN Attenuator STEIN Review UCB/SSL Nov 10, 2011

14. Electronics Mounting Rear view with Cover Shown Transparent Cross-Section with Detector Plane STEIN Review UCB/SSL Nov 10, 2011

15. STEIN in Context Electronics Cover Aperture Attenuator Mechanism STEIN Review UCB/SSL Nov 10, 2011

16. STEIN in Context

17. STEIN in Context STEIN Review UCB/SSL Nov 10, 2011

18. Mechanical Requirements Status • DONE Large FOV/Geometric Factor • TBD Little scattered light reaching detector • DONE 4 mm spaced HV deflectors spaced at least 2 mm from structure • DONE Detector 10 mm behind electrostatic deflectors • TBD Light tight behind detector • Retractable mechanical attenuator that • TBD Reduces particle flux by 99% • DONE Requires no power except when opening or closing • DONE Produces no large magnetic fields • DONE Instrument must fit into the CINEMA chassis • PARTIALLY DONE Instrument must withstand launch vibration levels STEIN Review UCB/SSL Nov 10, 2011

19. Current Status • Vibration Test at 14 GRMS – Mechanical Passed • Vibration Test at 18 GRMS – One unstaked screw came loose, otherwise passed • Thermal Test – Scheduled for Late November • 2nd STEIN instrument: 75% of Mechanical Parts Have Been Fabricated STEIN Review UCB/SSL Nov 10, 2011