It’s Alive! Performance and control of prototype Starbug actuators Roger Haynes, Andrew McGrath, Jurek Brzeski, David Correll, Gabriella Frost, Peter Gillingham, Stan Miziarski, Rolf Muller, Scott Smedley. Anglo Australian Observatory Current status of project

Deployable Payloads with Starbug Andrew McGrath, Roger Haynes. Anglo Australian Observatory Concept and applications

Three questions… What is Starbug? Why use it? Where’s the technology at now?

What is Starbug? Starbug is a focal plane positioning concept Microrobotic actuators patrolling across a physical surface to position payloads in a telescope’s focal surface Simultaneous motion of actuators –Configuration time independent of number of buttons –Highly redundant architecture –No large mechanisms

Why use it? Greater number of resolution elements per field (Larger telescopes, Adaptive optics) Sparse distribution of interesting targets within field Detector-limited instrumentation Reformatting the focal plane for efficiency –Fibre-fed MOS –IFUs –Image slicers –Deployable sub-field imagers –etc. Need to deploy and manipulate payloads within the focal plane Historically –Manually positioned –Robotic arms –Payloads supported on arms –Payloads supported on magnetic buttons on a field plate

Starbug Advantages Field configuration time Simultaneous activation of actuators Configuration time independent of, or reducing with bug numbers c.f. pick-and-place, where time is proportional to pickoff numbers e.g. 2dF takes ~1hr with 400 fibres; same bug numbers and plate size with bug speed of 0.5mm/s expect 2 mins.

Starbug Advantages Microtracking Adjust field configuration during an observation Accommodate variation in plate scale across FoV during tracking (continuously or in discrete steps) –e.g. 0.5”/hr at extremes of FMOS 30’ FoV, >2”/hr for 2dF –More important for finer spatial resolutions (AO, ELT) Otherwise need multiple observations

Starbug Advantages Positioner size and mass Starbug decouples size of robotic components from size of focal surface No plate exchange c.f. pick-and-place, requiring robot to span positioning range and possibly exchange focal plates

Starbug Advantages Redundancy Largely independent actuators Fewer single-point failure modes Graceful system degradation with failures

Starbug Advantages Scalability Scalable to different focal surfaces merely by changing field plate Scalable in pickoff numbers

Starbug Advantages Cryo accessibility Microrobotic technologies (e.g. piezo) can avoid lubricants, are vacuum- friendly, and operate at low temperatures No large mechanisms to design for low temps

Starbug Advantages Instrument upgrade path High degree of planned upgrading and future-proofing Modular architecture, easy to upgrade components Ideal prototyping environment on ‘live’, facility-class instrument

There is a variety of classes of instrument that suit the characteristics of Starbug. We now know what Starbug is. We know a bit about its characteristics.

Discrete object fibre-fed MOS Somewhat like 2dF/OzPoz/6dF except Starbug actuators in place of passive bugs with pick-and- place Easier cryo due to small Starbug mechanisms and minimal support equipment to be cooled OzPoz buttonStarbug equivalent

Fibre-fed Deployable IFU Pickoffs (dIFUps) Similar to FLAMES dIFUps (discrete subfields), or tileable for arbitrary contiguous area coverage

Subfield Imaging via image relay (mirrors and lenses) via coherent imaging bundles (poster , R.Haynes et al. “Advances in IR and imaging fibers for astronomical instrumentation”) via active imaging payloads –bare detectors on bugs

Relayed Image IFU MOS As for subfield imaging, but relay feeds spectrograph(s), KMOS-style Simulated Starbug image relay MOS field configuration, with 178 out of 200 bugs allocated to targets from 800 randomly distributed targets on a 300mm focal surface.

Active Science Payloads APDs, or other light sensors for photometry Deployable microspectrographs Detector/filter combinations Tunable filters Detector arrays

Subfield Correction High levels of AO correction ‘challenging’ for wide field Starbug may enable multi-object AO with low-order correction applied at the telescope level, across the field, and higher order correction applied locally by active bug payloads to the relevant subfields (cf Falcon, Hammer et al., OPM & LAM) May also be possible to do bug-based second order (residual) correction to subfields for aO or ADC errors Share the difficulty between global and local correction

Telescope infrastructure payloads Guide probes Wavefront sensors for active mirror control Eliminates need for ‘engineering field’

The Multi “Multi-Object- Instrument” Instrument Bug infrastructure decoupled from payloads No need for bug ‘standardisation’ on a single plate Simultaneous observing with mixed payload types Precedents: –FLAMES (discrete objects + dIFUps) –WFMOS (different fibres to different spectrograph types)

Where’s the technology at now? We now know what Starbug is. We know what it’s good for.

But surely it’s science fiction?

(The Starbug name comes from the name of a spacecraft in a British comedy science fiction television show called Red Dwarf. It crashed frequently.)

Actuator development Concept formed at AAO arising from AAO heritage of fibre positioning technologies 2dF – 6dF/OzPoz - Echidna

Technology Readiness Level NASA terminology TRL 1 Basic principles observed and reported TRL 2 Technology concept and/or application formulated TRL 3 Analytical and experimental critical function and/or characteristic proof-of-concept TRL 4 Component and/or breadboard validation in laboratory environment TRL 5 Component and/or breadboard validation in relevant environment TRL 6 System/subsystem model or prototype demonstration in a relevant environment (ground or space) TRL 7 System prototype demonstration in a space environment TRL 8 Actual system completed and “ flight qualified ” through test and demonstration (ground or space) TRL 9 Actual system “ flight proven ” through successful mission operations

Technology Readiness Level NASA terminology TRL 1 Basic principles observed and reported TRL 2 Technology concept and/or application formulated TRL 3 Analytical and experimental critical function and/or characteristic proof-of-concept TRL 4 Component and/or breadboard validation in laboratory environment TRL 5 Component and/or breadboard validation in relevant environment TRL 6 System/subsystem model or prototype demonstration in a relevant environment (ground or space) TRL 7 System prototype demonstration in a space environment TRL 8 Actual system completed and “ flight qualified ” through test and demonstration (ground or space) TRL 9 Actual system “ flight proven ” through successful mission operations Pick-and-place is here

Technology Readiness Level NASA terminology TRL 1 Basic principles observed and reported TRL 2 Technology concept and/or application formulated TRL 3 Analytical and experimental critical function and/or characteristic proof-of-concept TRL 4 Component and/or breadboard validation in laboratory environment TRL 5 Component and/or breadboard validation in relevant environment TRL 6 System/subsystem model or prototype demonstration in a relevant environment (ground or space) TRL 7 System prototype demonstration in a space environment TRL 8 Actual system completed and “ flight qualified ” through test and demonstration (ground or space) TRL 9 Actual system “ flight proven ” through successful mission operations Echidna is here

Technology Readiness Level NASA terminology TRL 1 Basic principles observed and reported TRL 2 Technology concept and/or application formulated TRL 3 Analytical and experimental critical function and/or characteristic proof-of-concept TRL 4 Component and/or breadboard validation in laboratory environment TRL 5 Component and/or breadboard validation in relevant environment TRL 6 System/subsystem model or prototype demonstration in a relevant environment (ground or space) TRL 7 System prototype demonstration in a space environment TRL 8 Actual system completed and “ flight qualified ” through test and demonstration (ground or space) TRL 9 Actual system “ flight proven ” through successful mission operations Starbug is here

First steps Demonstration of feasibility with ‘Kickbot’ as displayed at SPIE Glasgow 2004 Drive: Impulse Footprint: < 10mm Step size: < 1um Speed: a few mm/minute Orientation: up to ~20º No rotation Microtracking: Yes Payload potential: Good Electronics: 4 wire, high V, low I Drive frequency: Low

First steps Subsequent development as part of Opticon FP6 JRA5 ‘Smart Focal Planes’ group Targeted at MOMSI – multiobject spectroscopy for ELT Goal performance specifications: –footprint <10mm –operate under closed loop control –positioning accuracy ~1  m or better –accommodate microtracking to correct for field distortions (e.g. atmospheric refraction effect) –orientate payload to align optical relay pick-offs –patrol freely over a possibly curved focal surface –varying gravitational orientation from 0-90º –low temperature and vacuum environment.

Current bug performance

Elli Drive: Resonant Footprint: 26mm long Step size: ? Speed: Fast Orientation: 0-90º Limited rotation Microtracking: Limited Payload potential: ? Electronics: 4 wire, low V, high I Drive frequency: kHz

Res 1-5 Drive: Resonant Footprint: 10mm Step size: <1um Speed: Fast Orientation: 0-90º Rotation Microtracking: Yes Cryogenic operation: Good Payload potential: Good Electronics: 2 wire, low V, high I Drive frequency: 100s kHz

Res J Drive: Resonant Footprint: ~ 6mm Step size: ~ 0.8um Speed: ~ 0.7mm/s Orientation: 0-90º Rotation Microtracking: Yes Cryo operation: Slower 0.2mm/s Payload potential: Good Electronics: 4 wire, high V, low I Drive frequency: kHz

Impulse Drive: Inertial stick-slip Footprint: ~10mm Step size: Failed Speed: Failed Orientation: No Rotation in principle Microtracking: in principle Cryo operation: ? Payload potential: ? Electronics: 4 wire, low V, high I Drive frequency: s Hz

Stepper Drive: Inertial stick-slip Footprint: ~16mm Step size: <1um Speed: Not measured Orientation: ? Rotation: in principle Microtracking: Yes Cryo operation: ? Payload potential: Good Electronics: 4 wire, low V, high I Drive frequency: 100s Hz

Tri-Ped (Bi – Ped) Drive: Inchworm Footprint: ~18mm Step size: <1um Speed: Not measured Orientation: ? Rotation: Yes Microtracking: Yes Cryo operation: ? Payload potential: Good Electronics: 8 wire, high V, low I Drive frequency: 100s Hz

Crowd Surfer Drive: Travelling wave Footprint: Minimum ~ 6mm Step size: >1um Speed: ~0.5mm/s Orientation: ? Rotation: in principle Microtracking: in principle Cryo operation: ? Payload potential: Very good Electronics: Complex, high V, low I Drive frequency: 100s Hz

Metrology and control Camera imaging focal surface (FPI) 1/30th Pixel centoiding (3 sigma) demonstrated with Starbug and FMOS – Better possible? Closed loop control (Res- J) 10um (feedback control limit)

Metrology and control On-telescope FPI can be convenient by imaging through reflection in primary, camera mounted to spider Imagery tested using 2dF on AAT 1/20 th pixel easily achieved

Conclusions Starbug is a focal plane positioning concept using microrobotic actuators patrolling simultaneously across a surface to enable wide-field multiobject observation The concept is potentially cheap, light and robust compared with other positioning technologies, with short field reconfiguration times Starbug accommodates –Dynamic field reconfiguration (microtracking) –Cryogenic and vacuum operation –Active or passive payloads –Local (subfield) correction Candidate actuator technologies have already been developed, reaching TRL ~ 3

Drive: Resonant Footprint: ~ 6mm Step size: ~ 0.8um Speed: ~ 0.7mm/s Orientation: 0-90º Rotation Microtracking: Yes Cryo operation: Slower 0.2mm/s Payload potential: Good Electronics: 4 wire, high V, low I Drive frequency: kHz