# Presentation: 320557

## Section 25

_***Section 25***_
***Lightweight Flexible Solar Array***

*** ******. . . John Lyons***
*EO-1 Lightweight Flexible Solar Array Lead*

## Lightweight Flexible Solar Array (LFSA)

- Increase payload mass fraction.
**Description:**
- The LFSA is a lightweight photovoltaic(PV) solar array which uses thin film CuInSe2 solar cells and shaped memory hinges for deployment. Chief advantages of this technology are:
- Greater than 100Watt/kg specific energies compared to conventional Si/GaAs array which average 20-40Watts/kg.
- Simple shockless deployment mechanism eliminates the need for more complex mechanical solar array deployment systems.  Avoids harsh shock to delicate instruments.
**Validation:****     **
- The LFSA deployment mechanism and power output will measured on-orbit to determine its ability to withstand long term exposure to radiation, thermal environment and degradation due to exposure to Atomic Oxygen.
**Benefits to Future Missions:**
- This technology provides much higher power to weight ratios (specific energy) which will enable future missions to increase science payload mass fraction.

**Status:**
**see upcoming charts**
**Partners**
- AFRL, NASA/LaRC, Lockheed Martin (Boulder Co)

***Lightweight Flexible Solar Array (LFSA)***

## “As Run” Verification Matrix

## Projected Power On Time

## Changes Since Red Team Review

***Changes Since Red Team Review***

***No changes to Verification Matrix***
***No configuration changes***
***LFSA was powered up in idle mode during T/V II hot and cold plateaus***

## Special Topic Follow-Up:

***LFSA Repair, Modification, and Re-Integration***

*** ******. . . John Lyons***
*EO-1 Lightweight Flexible Solar Array Lead*

## LFSA Power Interface Issues

***LFSA Power Interface Issues***

***Post S/C environmental testing and final integration of LFSA with S/C indicated problem with readout of I-V data, which was diagnosed as power up sequence error  in software code within the LFSA microcontroller***
***Further examination of power interface logic from S/C to LFSA indicates that a “smart short failure scenario” in LFSA might result in degraded power services (+5V,15V,******-15V) to main S/C processor, putting mission at risk. ***
***Decision made on 11/24 to modify LFSA power interface to accept unregulated 28V input rather than current (+5,-15V, +15V) interface.***
***Plan developed with LM to modify current power interface and correct  microcontroller software:***
***Delta CDR (modified power, re-qual requirements) held Dec 3rd***
***Functional testing with S/C on Dec 20th***
***Environmental requalification (vib, thermal, EMI) Dec 20- Jan 15th***
***Reintegration with S/C on Jan 17th***
***Revised interface allows LFSA microcontroller to be powered up separately and turned off if it causes any problems.***

## Lightweight Flexible Solar Array(Revised Power Interface)

## LFSA Power Interface Issues

***LFSA Power Interface Issues***

***1)******	******Develop and present Delta CDR - Dec 3rd******	***_***Complete***_
***2)******	******Lockheed Martin to modify LFSA to ******	***_***Complete***_
***	******accommodate new power interface and ***
***	******functionally test unit with new ***
***	******micro-controller software at LM - 12/17/99***
***3)******	******Swales to modify and test S/C harness******	***_***Complete***_
***	******to new interface (before Dec 16) ***
***4)******	******Lockheed Martin to functionally test LFSA ******	***_***Complete***_
***	******with S/C at GSFC 12/21 ***
***5)******	******Lockheed Martin to perform environmental ******	***_***Complete***_
***	******re-qualification of LFSA at LM and GSFC  ***
***	******(thermal cycle, vibration at LM, EMI at GSFC)***
***	******Dec 27- Jan 12***
***6)******	******Reintegration of LFSA with EO-1 S/C - Jan 13******	***_***Complete***_

## LFSA Summary

***LFSA Summary***

***Recent re-integration and test demonstrated no residual risk to spacecraft***
***No Redbook candidates***
***LFSA ready to fly***