# Presentation: 885459

## Optical Assemblies for Space Environments: Characterization of W.L.Gore Flexlite with Diamond AVIMSfor Space Flight Environments 

*Optical Assemblies for Space Environments: Characterization of W.L.Gore Flexlite with Diamond AVIMS**for Space Flight Environments** *

- Melanie N. Ott
- Sigma Research and Engineering/
- NASA Goddard Space Flight Center
- More information: 301-286-0127, _[melanie.ott@gsfc.nasa.gov](mailto:melanie.ott@gsfc.nasa.gov)_
- URL:  nepp.nasa.gov/photonics
- misspiggy.gsfc.nasa.gov/photonics

- NASA Goddard Space Flight Center

- 7/22/98

## Optical Assemblies for Space Environments: Characterization of W.L.Gore Flexlite with Diamond AVIMSfor Space Flight Environments 

- Melanie N. Ott
- Sigma Research and Engineering/
- NASA Goddard Space Flight Center
- More information: 301-286-0127, _[melanie.ott@gsfc.nasa.gov](mailto:melanie.ott@gsfc.nasa.gov)_
- URL:  nepp.nasa.gov/photonics

*Technical Team: Shawn Macmurphy, Marcellus Proctor, Patricia Friedberg*

- NASA Goddard Space Flight Center

- 7/22/98

## Photonics Manufacturing and Testing Lab

- Parts, Packaging and Assembly Technologies Office
- NASA GSFC, Code 562

- NASA Goddard Space Flight Center

- 7/22/98

## Outline

**MLA Requirements & Components**
**Characterization plan**
**Materials Study Results**
**Vibration Testing & Results**
**Thermal Testing & Results**
**Radiation Parameters**
**Radiation Testing Results**
**Conclusions**

- NASA Goddard Space Flight Center

- 7/22/98

## MLA Requirements

- Large diameter optical fiber, 200 and 300 micron, NA of .22 for use at 1064 nm.
- High performance assembly;
-  Low insertion loss (< 0.4 dB)
-  Repeatability.
-  Stability in harsh environment
- -  thermal, vibration and radiation.
-  Non-outgassing components.
-  Assemblies 26.1 inches long used for beam delivery system, not interconnected.
- Parts selection to meet requirements:
-   Diamond AVIMs with custom ferrule drilling, D-6201.1
-   Part # E070040095VNAS1 Ferrule custom drilled for 220 fiber.
-   Part # E070040095VNAS2 Ferrule custom drilled for 330 fiber.
-   Part # 070015048V001, Hytrel boots.
-  W.L.Gore, Flexlite simplex cable, FON1173, FON1174
-   Polymicro Technologies optical fiber,
**  **FIA200220500, 200 micron, acrylate, .22 NA, step index
-   FIA300330500, 300 micron, acrylate, .22 NA, step index
-   Epoxy, Epo-Tek 353ND.

- NASA Goddard Space Flight Center

- 7/22/98

## AVIMs and Flexlite Assembly

- Terminations performed to NASA-STD-8739.5 and procedure 562-WI-8700.2

- NASA Goddard Space Flight Center

- 7/22/98

## Mercury Laser Altimeter

*Mercury Laser Altimeter*

- NASA Goddard Space Flight Center

- 7/22/98

## Characterization Plan 

- All testing conducted: recorded before and after optical performance data
-  as well as in-situ optical data.
- Vacuum Outgassing,
- All materials must pass ASTM-E595.
- Vibration Induced Effects
- Verified survival and operational ability during launch using typical launch parameters for small box components.
- 3 minutes per axis, 14.1 grms total, 3 assemblies tested.
- Thermal Induced Effects
- -30°C to +50 °C, 90 cycles, last 42 monitored, (tests are conducted at 10°C higher than expected environmental extremes).
- 25 minute soak, 2 °C/min ramp rates.
- Radiation Effects
- Space flight environments from GSFC are less than 1 rad/min and more typically less than 0.1 rads/min.  Two dose rates used to possibly provide a model for extrapolation to lower dose rates.
- 11.2 rads/min for lower dose rate, 22.7 rads/min for higher dose,
- Up to 30 Krads while maintaining a cold temperature of –20° C.
- Actual projected dose rate for MLA: 16.44 rads/day, .685 rads/hour, .011 rads/min

- NASA Goddard Space Flight Center

- 7/22/98

## Materials Results, nonmetallic parts

-   Cable
- - Flexlite passed when tested previously in configuration during development of ICESAT (GLAS) with acrylate coated fiber.
- - Cable does require preconditioning for thermal stability
- 	8 cycles, 60 min @ 60°C, 25 min @ -20°C, < 2°C/min
-   Connector Boots
- Hytrel 8068 require de-gas preconditioning,
- 102 to 1 Torr, 140°C, 24 hours.
- Once preconditioned, ASTM-E595 results were:
- 0.48 % TML, 0.10% CVCM.
-   Epoxy
- EpoTek 353ND is contained in GSFC outgassing database.

- NASA Goddard Space Flight Center

- 7/22/98

## Cable Designations and Initial Visual Inspection

| Assembly Code | Side A | Side B |
| --- | --- | --- |
| MP1 |  |  |
| MP2 |  |  |
| MP3 |  |  |

- Pre-environmental Testing Visual Inspection

- MPX Test assemblies were made of two AVIMS/AVIMS interconnected with an AVIMS adapter, each ~ 24 inches long.
- Presented above are end face pictures of the mated sides that were exposed to environmental testing

- NASA Goddard Space Flight Center

- 7/22/98

## Vibration Testing

- 3 minutes/axis, 14.1 grms total, 3 axis test

**X**

**Y**

**Z**

- Z axis orientation

- X axis orientation

- NASA Goddard Space Flight Center

- 7/22/98

## Vibration Parameters for Test

- Random Vibration Profile Parameters
- Based on EO-1 and MLA specifications

- 3 minutes/axis, 14.1 grms total, 3 axis test for mated pair

- NASA Goddard Space Flight Center

- 7/22/98

## Vibration Test Results: X axis MP1

- NASA Goddard Space Flight Center

- 7/22/98

## Vibration Test Results: Y axis MP1

- NASA Goddard Space Flight Center

- 7/22/98

## Vibration Test Results: Z axis MP1

- NASA Goddard Space Flight Center

- 7/22/98

## Vibration Test Results Summary

| Assembly Set | Vibration Test Axis | Max Induced Insertion Loss | Final Change in Insertion Loss Post Testing |
| --- | --- | --- | --- |
| MP1 | X | 0.0031 dB | 0.0028 dB |
| MP1 | Y | 0.0024 dB | 0.0012 dB |
| MP1 | Z | 0.0015 dB | 0.0006 dB |
| MP2 | X | -0.0002 dB* | -0.0027 dB * |
| MP2 | Y | -0.0006 dB* | -0.0012 dB * |
| MP2 | Z | 0.0027 dB | 0.0004 dB |
| MP3 | X | -0.0005 dB* | -0.0017 dB * |
| MP3 | Y | 0.0004 dB | 0.00 dB |
| MP3 | Z | 0.0003 dB* | -0.002 dB * |

- *Indicates an increase in power post vibration testing

- No endface damage was detected during post vibration visual inspection.

- NASA Goddard Space Flight Center

- 7/22/98

## Thermal Testing 

- -30°C to +50 °C, 90 cycles, last 42 cycles monitored optically.

- Program malfunction caused lack of data collected during the first 48 cycles.

- NASA Goddard Space Flight Center

- 7/22/98

## Thermal Testing Results

- Insertion loss for MP1
- During 68th  to 75th cycle (Red) with temperature (Black).
- Insertion loss increases with decreasing temperature.

- Example of data collected for all assemblies
- MP1 during 42 cycles
- (after initial 48 cycles unmonitored)

- NASA Goddard Space Flight Center

- 7/22/98

## Thermal Testing Results Summary

| Assembly Set | Δ insertion loss during testing | Overall Change in loss post testing, 90 cycles | Max insertion loss during testing | Visual Inspection post test side A | Visual Inspection post test side B |
| --- | --- | --- | --- | --- | --- |
| 
MP1 | 
0.09 dB | 
-0.044 dB
power increase |  
0.058 dB |  |  |
| 
MP2 | 
0.07 dB | 
-0.015 dB power increase | 
0.037 dB |  |  |
| 
MP3 | 
0.04 dB | 
-0.035 dB power increase | 
0.024 dB |  |  |

- NASA Goddard Space Flight Center

- 7/22/98

## Radiation Test Parameters

- Tested up to 30 krads in Cobalt 60 chamber:
-   10 m of  FON1173 (200 micron core fiber)
-   10 m of  FON1174 (300 micron core fiber)
-   High dose rate 22.7 rads/min
-   Low dose rate 11.2 rads/min
-   While maintaining at temperature of -20°C.
-   Monitored optical power at 850 nm @
-      < 1 micro watt of power.

- NASA Goddard Space Flight Center

- 7/22/98

## Radiation Results for High Dose Test

- Induced attenuation for both 200 (red), and 300 (blue) micron cable up to 30 krads

- 22.7 rads/min
- 10 meters of cable

- NASA Goddard Space Flight Center

- 7/22/98

## Radiation Results for Low Dose Test

*Radiation Results for Low Dose Test*

- Induced attenuation for both 200 (red), and 300 (blue) micron cable up to 30 krads

- 11.2 rads/min
- 10 meters of cable

- Small “glitch” at ~ 20 krads due to fire alarm closing chamber shutter

- NASA Goddard Space Flight Center

- 7/22/98

## Radiation Results Summary

| Part # | Type OF
(microns) | Dose rate | Atten. @ 30 krads | Ave. temp during testing | Expected atten. 26.1 inches @ 30 krads |
| --- | --- | --- | --- | --- | --- |
| FON1173 | 200  | 11.2 rads/min | 1.024 dB | -24.1°C | 0.068 dB |
| FON1174 | 300 | 11.2 rads/min | 0.917dB | -24.1°C | 0.061 dB
 |
| FON1173 | 200 | 22.7 rads/min | 0.892 dB | -18.3°C | 0.059 dB
 |
| FON1174
 | 300 | 22.7 rads/min | 0.818 dB | -18.3°C | 0.054 dB
 |

-   Results for 200 and 300 micron fiber are ~ identical.
-   Results for high and low dose rate tests for both fibers also ~ identical.
-   Extrapolation model can not be used without further experimentation.
-   Dose rate differences are attributed with difference in thermal environment.

- NASA Goddard Space Flight Center

- 7/22/98

## Conclusions

- In general, Flexlite and AVIMs assemblies performed with superiority in comparison to other studies conducted in the past (nepp.nasa.gov/photonics for more information).
- Vibration and Thermal Conclusions: Final change in insertion loss after both vibration and thermal testing is as follows:
-  MP1, -.04 dB, resulting power increase
-  MP2, -.02 dB, resulting power increase
-  MP3, -.04 dB, resulting power increase
- Radiation Conclusions:
- - Since extrapolation method can not be used best assumption is by usage of lower dose rate results.  Actual MLA dose rate will be .011 rads/min.
- Using 11.2 rads/min results, expected losses will be less than .07 dB for each 26.1 inch assembly at –20oC at a total dose of 30 krads under “dark conditions” or without power enough to provide photobleaching annealing effects.
- Both FON1174 and FON1173 perform identical.

- Post all environmental testing:    MP1, 0.03 dB;    MP2, 0.05 dB;    MP3, 0.03 dB

- NASA Goddard Space Flight Center

- 7/22/98

## Acknowledgements

- Special thanks to NASA Electronic Parts and Packaging Program & MESSENGER, Mercury Laser Altimeter Program for funding of this work.
- Additional thanks to
- Dr. Henning Leidecker (always!)
- Darryl Lakins
- Dr. Charles Barnes
- Phillip Zulueta
- Luis A Ramos-Izquierdo
- Arlin Bartels
- For resources and program management support

- For more information see the websites:
- _[http://nepp.nasa.gov/photonics](http://nepp.nasa.gov/photonics)_
- _[http://misspiggy.gsfc.nasa.gov/photonics](http://misspiggy.gsfc.nasa.gov/photonics)_

- Special thanks to the WebEx team for making this possible
- Jeannette Plante & Carl Szabo

- NASA Goddard Space Flight Center

- 7/22/98