# Presentation: 524103

## 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.

- November 23, 2004

## Siderostat Assembly (an old view)

- A “**Siderostat**” is a flat steering mirror that keeps the line of sight of telescope _**STAT**_ionary in _**SID**_ereal 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)

- November 23, 2004

## Siderostat Mirror Points Over Field of Regard

- Mirror Normal

- Incoming Starlight

- TelescopePrimary Mirror

- Siderostat Mirror

- November 23, 2004

## Siderostat Mirror Points Over Field of Regard

- Sid aimed upward

- TelescopePrimary Mirror

- Incoming Starlight

- November 23, 2004

## Siderostat Mirror Points Over Field of Regard

- Sid aimed downward

- TelescopePrimary Mirror

- Incoming Starlight

- November 23, 2004

## Siderostat Mirror Points Over Field of Regard

- TelescopePrimary Mirror

- Siderostat Mirror moves only 7.5°(i.e. ±3.75°)

- 15° Field of Regard (FOR) on the sky

- November 23, 2004

## Guide Star Steering

- OpticalSystem

- 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.

- SIM Compressor

- Conjugate Points:

- Corner Cube (CC)

- FSM

- November 23, 2004

## Guide Star Steering

- SIM Compressor

- Corner Cube (CC)

- FSM

- 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.

- November 23, 2004

## Guide Interferometer Pointing

- Fast Steering Mirror (FSM) used to steer line of sight for Guide Compressors
- Corner Cube (CC) and FSM at Conjugate Points

- Fast Steering Mirror

- Primary Mirror

- Secondary Mirror

- Tertiary Mirror

- Pathlength dither optic

- Portion of CC used by Internal Met

- November 23, 2004

## 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

- Fast Steering Mirror

- Primary Mirror

- Secondary Mirror

- Tertiary Mirror

- Pathlength Dither Optic

- November 23, 2004

## 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

- Fast Steering Mirror

- Primary Mirror

- Secondary Mirror

- Tertiary Mirror

- Pathlength Dither Optic

- November 23, 2004

## Triple Corner Cube (TCC) Arrangement

- Beam footprints on retroreflector

- incoming beam

- outgoing beam

- intermediate bounce

- All beam footprints must lie within the retroreflector and clear all edges, with margin.

- November 23, 2004

## Double Corner Cube (DCC) on Face of Siderostat

- Here, we use only  two of the three corners

- November 23, 2004

## One Science Interferometer

- Compressor

- Compressor

- High-Bandwidth Optical Delay Line

- Astrometric Beam Combiner

- Siderostat

- Siderostat

- Low-Bandwidth Optical Delay Line

- November 23, 2004

## Add One Guide Interferometer

- First Guide constrains one degree of freedom

- November 23, 2004

## Add a Second Guide Interferometer

- Second Guide constrains an orthogonal degree of freedom

- November 23, 2004

## Add External Metrology Subsystem

- External Metrology ties the science baseline to the guide baseline

- November 23, 2004

## External Metrology Subsystem Alone

**External MET**
**Beam Launchers**

- November 23, 2004

## Add Precision Support Structure

**Precision Support Structure (PSS)****connects and supports elements stably**

- November 23, 2004

## Instrument Configuration

**Optical Delay Lines (ODLs)**

**Guide**
**Corner Cube**

**Science**
**Compressor**

**Guide**
**Compressor**

**External MET**
**Beam Launchers**

**External Metrology**
**Beams**

**Guide Interferometer ****Fields of View**

**Science Interferometer Field of Regard**

**Astrometric Beam ****Combiners (ABCs)**

- November 23, 2004

**Notes:**
This slide shows an oblique view of the L-15x configuration. 
As a result of the reorientation of the corner cubes, the external metrology truss was reshaped into a more symmetric triangular prism.  This was necessary to meet the constraints on the viewing directions of the corner cubes. The external metrology fields of the view of the various corner cubes are very constrained.  Many are at close to grazing angles.  The corner cube positions cannot be adjusted much before losing external met beams.  
The guides share a common baseline of length 8.9m.  The science baselines are now both 10m long.  There are 15 external metrology beams.  
The science telescopes are now back-to-back.  This has widened the base of the triangular end view.  It has also pushed up the top of the “tent” as constrained by the corner cube geometry.  
The inset figure shows the relation between the FORs and the Sun shades.

## Top View

- Science interferometers maintain preferred translational symmetry

- Guide interferometers have mirror symmetry

- November 23, 2004

**Notes:**
This shows a top view of the L-15x configuration.  The X shape of the intersecting beams in this view is where the “x” in the name comes from.  
This means that the baseline is never directly measured. This means that  during normal operation, only 14 beams will be useable simultaneously.

## Top and Side Views

- November 23, 2004

## Overall Configuration (deployed)

- Solar Array

- HGA

- LGA

- Spacecraft

- COL Bay 2

- COL Bay 1

- PSS Truss

- Star Tracker

- Siderostat
- And DCC

- Compressor

- TCC

- ABCs (3)

- ODLs

- November 23, 2004

## SIM Configuration

- Stowed

- Spacecraft

- Deployed

- PSS truss

- COL bay enclosures

- Vibration isolators

- Contamination covers

- MLI covering of PSS truss and COL bay enclosures not shown

- November 23, 2004

## Stowed in Fairing

- November 23, 2004