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 Fourier-Kelvin Stellar Interferometer Electro-Mechanical Jason Budinoff 24 May 2002

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 Budinoffp224 May 2002FKSI Mechanism Design Drivers Design operating environment 20K 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 0.02 arcsec co-alignment requirement pushes state of art for cryogenic 5 DOF fast-steering mechanisms All actuators will have dual windings (coils) for redundancy All mechanisms drive electronics will be fully redundant ETU & flight spares

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 Budinoffp324 May 2002FKSI FKSI Mechanisms Deployments – Truss Hinge(s) Release Drive Active Latch – Solar Array(s) Release – Sun Shield(s) Release Combiner Telescope – Focus At each telescope (5x) – Option 1 Tip/Tilt/Decenter/ Focus secondary – 5 DOF Shutter – Option 2 Tip/Tilt telescope Tip/Tilt/Decenter/ Focus secondary – 5 DOF Shutter At each delay line – 2 Tip/tilt – Piston

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 Budinoffp424 May 2002FKSI Deployments 1: Truss hinge(s) Truss Hinge Mechanism – Large HOP-actuated helical driver High-Output Paraffin (wax) linear actuator – Extensive flight heritage, CIRS, GLAS, CASSINI, SMEX… Thermostat required ~270 degree stroke with very high torque Slow, controlled deployment Mechanical passive latching lock at end of travel Mass ~12 kg Dissipation ~20 Watt while operating Active Latch mechanism – Provides increased stiffness across hinge joint after deployment and engagement of passive latch – 3 point locking of truss boom segments Flight heritage ISS CLA, PAS, ESPAD, Ball Aerospace, others Geared stepper motor Power-off hold Mass ~ 5 kg Dissipation ~ 15 Watt while operating

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 Budinoffp524 May 2002FKSI Deployments 2: Solar Array(s) Solar Array Deployment Mechanism – Deploys Non-articulating solar array(s) Shockless pyro, nitenol, or band-release Spring / damper driven Passive mechanical latching Thermostat required Mature technology, extensive flight heritage Mass ~5 kg per array

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 Budinoffp624 May 2002FKSI Deployments 3: Solar Shields Solar Shield Deployment Mechanism – Deploys non-articulating, multi-layer solar shields – Similar to solar array deployment Shockless pyro, nitenol, or band-release Spring/damper driven Passive mechanical latching Mass ~ 10 kg

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 Budinoffp724 May 2002FKSI Combiner Telescope Secondary Mirror Focus Mechanism – CIRS-type linear scanner +/- 13 mm (0.5 inch) range 0.5 micron resolution Launch lock required 100 mW dissipation 2.5 kg w/ combiner secondary mirror

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 Budinoffp824 May 2002FKSI Delay Lines (per line) Delay Line Tip/Tilt Mechanism 2 per delay line – 2-axis fast steering mirror Extensive heritage, GLAS, TOP HAT, Left Hand Design, Ball Aerospace… Dynamically balanced +/- 2 degree range 1 microradian (0.2 arcsec) resolution 100 mW avg dissipation 1.5 kg Delay Line Piston Mechanism – +/- 1 cm range – 0.1 micron resolution – CIRS-type linear scanner – Launch lock required – 100 mW avg dissipation – 4 kg w/ dihedral

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 Budinoffp924 May 2002FKSI Collector Telescopes Option 1 Fixed Telescope Secondary 6 DOF mechanism – Provides tip, tilt, focus, decenter Dynamically balanced +/- 2 degrees range tip/tilt 0.01 arcsec resolution +/- 5 mm range focus, decenter 0.1 micron resolution – Hexapod pointer 6 Voice coil / linear flexure struts Dissipation ~400 mW New technology development Shutter Mechanism – Magnetic shutter Power-off open – DIRBE, CIRS heritage < 0.5 mW dissipation when closed Mass 1.5 kg

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 Budinoffp1024 May 2002FKSI Collector Telescopes Option 2 Steering Telescope Secondary 6 DOF mechanism – Provides tip, tilt, focus, decenter Dynamically balanced +/- 2 degrees range tip/tilt 0.01 arcsec resolution +/- 5 mm range focus, decenter 0.1 micron resolution – Hexapod pointer 6 Voice coil / linear flexure struts Dissipation ~400 mW New technology development Telescope tip/tilt mechanism – Duty cycle 1 / hour – +/- 3 degree range – 0.1 arcsec resolution Power-off hold Flexure-mounted telescope 2 Geared stepper motor cam drives Mass ~ 4 kg ~5W dissipation (transient) Shutter Mechanism – Magnetic shutter – DIRBE, CIRS heritage < 0.5 mW dissipation when closed Power-off open

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 Budinoffp1124 May 2002FKSI Mechanisms Electronics Separate electronics box in “warm” area of s/c Baseline 10 boards w/full redundancy 10 board box will weigh ~4 kg Total average power 60 Watts (GLAS MECH board)

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 Budinoffp1224 May 2002FKSI Mechanisms Summary 30(34) total – 1 collector telescope focuser $0.8M – 5 telescope secondary 6 DOF pointers $7M – 10 delay line tip/tilts $2M – 5 delay line pistons $1.5M – 5 shutters $0.5M – 1(2) Truss deployment drives $1.5(2) M – 1(2) Truss active latch drives $1.5 (2) M – 1(2) Array release & lock $0.4 (.5) M – 1(2)Shield release & lock $1.5 (2) M – Electronics cost rolled into each mechanism cost Mechanisms costs: – < $20M – *VERY* preliminary, will probably grow with further analysis

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 Budinoffp1324 May 2002FKSI Future Points of Pondering All mechanisms within current state of art – secondary pointer pushing it, but possible. Could solar array and sunshield deployments be combined? Truss booms, solar array deployments should be designed such that failure of one deployment does not preclude others; e.g. If one boom fails to deploy, the solar arrays or sunshields cannot deploy. – Provided that this does not introduce too much engineering difficulty, still fit in Delta IV medium – Could pre-combiner telescope optical train or alignment logic be modified to have fewer degrees of freedom? This would reduce number of mechanisms.

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 Budinoffp1424 May 2002FKSI Telescopes SIRTF, CIRS-heritage – Central metering tube mated to optical bench – Primary flexure-mounted to optical bench Telescope assembly inside of baffle tube Baffled secondary Shutter Mechanism Telescope Tip / Tilt Mechanism Baffle / Metering Tube Spider blades Secondary Tip / Tilt / Decenter / Focus Mechanism

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 Budinoffp1524 May 2002FKSI