1. N A S A G O D D A R D S P A C E F L I G H T C E N T E R I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Earth Atmosphere Solar-Occultation Imager (EASI) Electro-Mechanical Jason Budinoff 2 August 2002

2. Electro-Mechanical I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Jason Budinoffp22 August 2002EASI Mechanism Design Drivers Design operating environment 40-50+ K 50mm beam diameter System-level alignment rate of > 1 Hz requires fast response, high duty cycle mechanisms – Dynamic balancing probably required to reduce mechanism- induced jitter System level 0.1 arcsec co-alignment requirement All actuators will have dual windings (coils) for redundancy Some mechanisms dynamically balanced for minimal jitter input All mechanism drive electronics will have partial/on-board redundancy Costing assumes prototype, single ETU, flight units, ~50% flight spares

3. Electro-Mechanical I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Jason Budinoffp32 August 2002EASI EASI Mechanisms At each telescope (5x) – Tip/Tilt entire telescope – Tip/Tilt/Piston/Decenter secondary – Shutter At each delay line (5x) – Tip/Tilt single flat element – Piston dihedral element Combiner Telescope (1x) – Tip/Tilt/Piston/Decenter secondary – Shutter Spectrometer – Lens flip mechanism

4. Electro-Mechanical I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Jason Budinoffp42 August 2002EASI Delay Lines (per line) Delay Line Tip/Tilt Mechanism – 2-axis fast steering mirror Extensive heritage, GLAS, TOP HAT, Left Hand Design, Ball Aerospace… Dynamically balanced +/- 1 degree range 0.1 microradian (0.02 arcsec) resolution 200 mW avg dissipation, >50% duty cycle 2.5 kg Delay Line Piston Mechanism – CIRS-type linear scanner – +/- 10 mm range – 0.05 micron resolution – Launch lock required – Dynamically balanced – 200 mW avg dissipation, >50% duty cycle – 7 kg w/ dihedral – New Technology = Development Risk

5. Electro-Mechanical I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Jason Budinoffp52 August 2002EASI Collector Telescopes Secondary 5(6) DOF mechanism – Provides tip, tilt, focus, decenter +/- 2 degrees range tip/tilt 0.01 arcsec resolution +/- 5 mm range focus, decenter 0.1 micron resolution – Hexapod pointer w/ jitter attenuation – 6 stepper-motor driven struts, power off hold – Piezo- or voice coil attenuators Infrequent use, seasonal duty cycle for steppers, >50% for attenuators Mass ~3.1 kg Telescope tip/tilt mechanism – +/- 3 degree range – 0.1 arcsec resolution Power-off hold Flexure-based 2 Geared stepper motor /cam drives Mass ~ 4 kg ~5W dissipation (transient) Infrequent use, seasonal duty cycle Shutter Mechanism – Magnetic scissors shutter – DIRBE, CIRS heritage < 0.5 mW dissipation when closed Power-off open Dynamically balanced ~1.5 kg TBD

6. Electro-Mechanical I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Jason Budinoffp62 August 2002EASI Combiner Telescope Secondary 5(6) DOF mechanism – Provides tip, tilt, focus, decenter +/- 2 degrees range tip/tilt – 0.01 arcsec resolution +/- 5 mm range focus, decenter – 0.1 micron resolution – Hexapod pointer w/ jitter attenuation 6 stepper-motor driven struts, power off hold Piezo- or voice coil attenuators Infrequent use, seasonal duty cycle for steppers, >50% for attenuators Mass ~3.1 kg TBD DCATT, LANL/Honeywell VISS New Technology = Development Risk Shutter Mechanism – Magnetic scissors shutter – DIRBE, CIRS heritage < 0.5 mW dissipation when closed Power-off open Dynamically balanced

7. Electro-Mechanical I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Jason Budinoffp72 August 2002EASI Spectrometer 1-2 micron Coarse/Fine Piston Adjustment Mechanism – Rotates 50mm lens into/out of beam in 1-2 channel – Repeatability to +/-.5 degree, +/-2 mm Fairly insensitive to repeatability error – Stepper motor – Power-off position hold – HST heritage – Infrequent use, seasonal duty cycle – Mass 2 kg

8. Electro-Mechanical I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Jason Budinoffp82 August 2002EASI Mechanisms Electronics Separate electronics box in “warm” area of s/c Baseline 6 boards w/partial (on-board) redundancy 6 board box will weigh ~4 kg – Delay Line Piston Board – Delay Line Tip/Tilt Board – Secondary Mechanism Board – Shutter Board – Telescope Tilt Board – Secondary Power (+/-5V, +/-28V) Conditioning Board Total average power 66 Watts (GLAS MECH board)

9. Electro-Mechanical I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Jason Budinoffp92 August 2002EASI Mechanisms Summary 23 total – 6 telescope secondary 5(6) DOF pointers – 5 delay line tip/tilts – 5 delay line pistons – 5 telescope shutters – 1 focal plane shutter – 1 lens flip – 6 boards

10. Electro-Mechanical I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Jason Budinoffp102 August 2002EASI Mechanisms Cost Estimate MechanismsNRE, $KEA, $KQTY TOTAL, $K EA x QTY NET TOTAL, $K TOTAL + NRE 5(6) DOF Secondary Mechanism 30004009(6)36006600 Delay Line Tip/Tilt Mechanism 10001808(5)14402440 Delay Line Piston Mechanism 30004008(5)32006200 Telescope Shutter3001008(5)8001100 Focal Plane Shutter3001002(1)200500 Lens Flip Mechanism3001002(1)200500 Electronics Box, Harness10002001(1)2001200 Totals8900964018,540 -NRE includes manpower, breadboard, 1 engineering unit & supporting electronics & qualification environmental testing. -unit price (EA) includes manpower, 1 flight unit & acceptance environmental testing. -qty is shown as purchased(needed for flight); eg 8(5) means purchasing 8 and flying 5. This reflects ~50% flight spares

11. Electro-Mechanical I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Jason Budinoffp112 August 2002EASI Future Work 1 Development of new technology mechanisms – Some EASI mechanisms require 1-2 orders of magnitude increase in state-of-the-art performance (range/resolution/stability) in cryogenic environment. Secondary 5(6) DOF mechanism – Very high dynamic range, minimum power dissipation – Integrated vibration attenuation – Dynamic balancing – Tight packaging Delay line piston mechanism – Very high dynamic range, minimum power dissipation – Integrated vibration attenuation – Dynamic balancing Supporting facilities for 0.01 arcsecond-level stable measurements & alignments – Verification of individual mechanism performance will require STABLE interferometric, cryogenic facility setup.

12. Electro-Mechanical I n s t r u m e n t S y n t h e s i s a n d A n a l y s i s L a b o r a t o r y Jason Budinoffp122 August 2002EASI Future Work 2 Complexity of delay line control algorithm – Delay line controller will require multiple, recursive, nested loops – Observatory delay lines will operate at high rates >10 Hz? – This causes a flow-down to the individual mechanisms Each delay line correction will require many iterations in mechanism positions – Mechanisms will require very tight controllers, with settle times in the low millisecond range to 0.01 (+/-0.005” !!) arcsecond, operating in concert with vibration attenuation controller.