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Siderostat Assembly (an old view)

The slides in this collection are all related and should be useful in preparing a presentation on SIM PlanetQuest. Note, however, that there is some redundancy in the collection to allow users to choose slides best suited to their needs.

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Siderostat Assembly (an old view)

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  1. The slides in this collection are all related and should be useful in preparing a presentation on SIM PlanetQuest. Note, however, that there is some redundancy in the collection to allow users to choose slides best suited to their needs. Some slides appear to be duplicates (e.g. “Siderostat mirror points over field of regard”). These slides show animation when viewed rapidly in succession.

  2. Siderostat Assembly (an old view) A “Siderostat” is a flat steering mirror that keeps the line of sight of telescope STATionary in SIDereal space. As the platform moves around, the Sid compensates. It also allows the line of sight to be aimed over a region of sky without moving the platform or the telescope. Telescope line of sight is rotated about two orthogonal axes centered on the front face of the Sid by a gimbals assembly. A corner cube retroreflector will also be mounted with its vertex here (see slide later on)

  3. Siderostat Mirror Points Over Field of Regard Incoming Starlight Mirror Normal TelescopePrimary Mirror Siderostat Mirror

  4. Siderostat Mirror Points Over Field of Regard Incoming Starlight Sid aimed upward TelescopePrimary Mirror

  5. Siderostat Mirror Points Over Field of Regard Incoming Starlight Sid aimed downward TelescopePrimary Mirror

  6. Siderostat Mirror Points Over Field of Regard 15° Field of Regard (FOR) on the sky TelescopePrimary Mirror Siderostat Mirror moves only 7.5°(i.e. ±3.75°)

  7. Guide Star Steering OpticalSystem Conjugate Points: Light passing though one conjugate point … … will pass though other conjugate point For SIM’s telescopes, we place Fast Steering Mirror and Corner Cube (CC) at Conjugate Points. This keeps the Internal Metrology Beam centered on CCs as the Fast Steering Mirror moves starlight with pointing changes. FSM Corner Cube (CC) SIM Compressor

  8. Guide Star Steering OpticalSystem Conjugate Points: Light passing though one conjugate point … … will pass though other conjugate point For SIM’s telescopes, we place Fast Steering Mirror and Corner Cube (CC) at Conjugate Points. This keeps the Internal Metrology Beam centered on CCs as the Fast Steering Mirror moves starlight with pointing changes. FSM Corner Cube (CC) SIM Compressor

  9. Guide Interferometer Pointing • Fast Steering Mirror (FSM) used to steer line of sight for Guide Compressors • Corner Cube (CC) and FSM at Conjugate Points Portion of CC used by Internal Met Primary Mirror Secondary Mirror Tertiary Mirror Fast Steering Mirror Pathlength dither optic

  10. Guide Interferometer Pointing • FSM used to steer line of sight for Guide Compressors • CC and FSM at Conjugate Points Portion of CC used by Internal Met Primary Mirror Tertiary Mirror Secondary Mirror Pathlength Dither Optic Fast Steering Mirror

  11. Guide Interferometer Pointing • FSM used to steer line of sight for Guide Compressors • CC and FSM at Conjugate Points Portion of CC used by Internal Met Primary Mirror Secondary Mirror Tertiary Mirror Pathlength Dither Optic Fast Steering Mirror

  12. Triple Corner Cube (TCC) Arrangement Beam footprints on retroreflector outgoing beam incoming beam All beam footprints must lie within the retroreflector and clear all edges, with margin. intermediate bounce

  13. Double Corner Cube (DCC) on Face of Siderostat Here, we use only two of the three corners

  14. One Science Interferometer Compressor High-Bandwidth Optical Delay Line Siderostat Low-Bandwidth Optical Delay Line Compressor Astrometric Beam Combiner Siderostat

  15. Add One Guide Interferometer First Guide constrains one degree of freedom

  16. Add a Second Guide Interferometer Roll about baseline does not affect measurements (to first approximation) Second Guide constrains an orthogonal degree of freedom

  17. Add External Metrology Subsystem External Metrology ties the science baseline to the guide baseline

  18. External Metrology Subsystem Alone External MET Beam Launchers

  19. Add Precision Support Structure Precision Support Structure (PSS)connects and supports elements stably

  20. Instrument Configuration Guide Interferometer Fields of View Science Interferometer Field of Regard External Metrology Beams Guide Corner Cube Guide Compressor Optical Delay Lines (ODLs) Astrometric Beam Combiners (ABCs) External MET Beam Launchers Science Compressor

  21. Top View Science interferometers maintain preferred translational symmetry Guide interferometers have mirror symmetry

  22. Top and Side Views

  23. Overall Configuration (deployed) Spacecraft COL Bay 1 PSS Truss TCC COL Bay 2 HGA LGA Star Tracker ODLs ABCs (3) Siderostat And DCC Solar Array Compressor

  24. SIM Configuration Vibration isolators Stowed PSS truss Contamination covers MLI covering of PSS truss and COL bay enclosures not shown Deployed COL bay enclosures Spacecraft

  25. Stowed in Fairing

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