# Presentation: 893772

## MAXIM Periscope Module

**Mechanical Systems**
**Joe Pellicciotti**
**Mick Correia**
**Dave Palace**
**25 April 2003**

## Mechanical Design Requirements

**Mass Efficiency**
- 2 periscope assemblies (2 input apertures) on a single bench
- Trade study on bench materials
- Trade 2 bench assemblies in a single enclosure
**Thermal design will provide Delta-T stability of the periscope to be better than 0.020K**
- Select materials and design configuration that will meet alignment stability requirements at this temperature stability
- Stability required for ~3 hour observations
**Mechanical Stability Requirements:**

| DOF | X | Y | Z | ØX
(Yaw) | ØY
(Pitch) | ØZ
(Roll) |
| --- | --- | --- | --- | --- | --- | --- |
| Mirror Stability Tolerance | 
±1.7nm | 
±0.3mm | 
±94.7nm | 
±6.9arcmin | 
±2.3marcsec | 
±0.13arcsec |

## Periscope Assembly

**Entrance Aperture**
**(Thermal Collimator)**

**Shutter Mechanism**
**(one for each aperture)**

**Assy. Kinematic Mounts (3)**

## Periscope Assembly (cont.)

## Optical Bench & Mirrors

**Optical Bench & Mirrors**

**Pitch**

**Roll**

**Translate**

**Translate**

**Mirror #1**

**Mirror #2**

**Mirror #3**

**Mirror #4**

**3 DOF Mechanism**

**1 DOF Mechanism**

**Main Optical Bench**

**Mirrors**
**(300mm x 200mm x 50mm)**

**Entrance**
**Aperture**

**Exit**
**Aperture**

## Optical Bench Details

**Optical Bench Details**

**Secondary Bench **
**Flexures (4/Bench)**

**Main Optical Bench**

**Secondary**
**Optical Bench**
**(Mirrors 2 & 3)**

**Secondary Bench**
**Translation Mechanism**

## Launch Configuration Layout

**Delta IV ****ø5m x L14.3m**

**24 Free Flyer Satellites (4 Apertures ea.)**
**1 Hub Satellite (12 Apertures)**
**1 Detector Satellite**

**Ø4.75m**

## Optical Bench Material Options

| 
Material | Main Optical Bench Mass (Kg) | Potential Mass Optimization (% Reduction) | Required Thermal Stability† (°K) | Mfg. Cost‡ | Mfg. Risk‡ | 
Pros | 
Cons |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Super Invar | 22.2 | 30% | 0.0581 | 4 | 4 | Great thermal stability | Heavy & tricky to machine |
| SiC (Sintered) | 8.5 | 50% | 0.0087 | 5 | 5 | Very light weight & good thermal stability | Relatively new material, cost high & mfg. risks unknown |
| Titanium (6Al-4V) | 12.4 | 23% | 0.0020 | 3 | 1 | Light weight & stiff | Thermal stability reqmt is low |
| Beryllium | 4.5 | 45% | 0.0015 | 5 | 5 | Extremely light weight | Thermal stability reqmt is low & mfg costs are high |
| Composite (GFRP) w/metallic support blocks | 5.7 | 20% | 0.1744
(CME Shrinkage ~3.9μm in X-Dir) | 3 | 3 | Extremely light weight & great thermal stability | Moisture abs. distortion unknown – may require more mechanisms.
Low thermal conduction (high gradient) |

- † Thermal Stability based on bulk temperature change
**‡** Cost & Mfg Risk rated from 1 to 5 with 5 being the highest

## Mass Breakdown – Invar Bench

## Summary, Recommendations & Future Work

**Thermal stability requirement on the optical bench may be reduced if observation times are short (hours vs. days)**
**Composite bench may require additional mechanisms or stroke to compensate for moisture evaporation distortions**
**Baseline bench configuration has room for additional mass optimization**
**Future Work:**
**Determine the allowable gradient through the optical bench that will meet distortion requirements.**
**Perform detailed trade study on optical bench materials**
- Thermal / Structural analysis
- Launch Dynamics analysis
- Investigate GFRP bench as next best candidate
- Include methods to limit moisture absorbtion
**Possibly combine 2 main benches into a single enclosure (4 entrance apertures) to reduce overall mass and volume**

## Back-up Information

**Flexure system option for secondary Mount**

## Secondary Bench TranslationalPositioning System Kinematics

- _Reference & Acknowledgement__:_
- Nicholas G. Dagalakis, John A. Kramar, Edward Amatucci, and Robert Bunch,
- “**Kinematic Modeling and Analysis of a Planar Micro-Positioner,”**** **
- National Institute of Standards and Technology, Gaithersburg, Maryland  20899

**System Provides smooth linear motion **
**Negligible cross-axis motion**