LFSA

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Section 25 Lightweight Flexible Solar Array
. . . John Lyons EO-1 Lightweight Flexible Solar
Array Lead
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Lightweight Flexible Solar Array (LFSA)

• Technology Need
• 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)
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As Run Verification Matrix
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Projected Power On Time
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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

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Special Topic Follow-Up LFSA Repair,
Modification, and Re-Integration
. . . John Lyons EO-1 Lightweight Flexible Solar
Array Lead
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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.

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Lightweight Flexible Solar Array(Revised Power
Interface)
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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

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LFSA Summary

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