WMKO%20Next%20Generation%20Adaptive%20Optics:%20AO%20System%20Design%20Impact%20of%20Cost%20Savings%20Ideas

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WMKO Next Generation Adaptive OpticsAO System
Design Impact of Cost Savings Ideas

• Don Gavel
• December 19, 2008

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AO Design Impact - Highlights

• We revisited the AO architecture to look for cost
  savings
• Considered several options of 1 and 2 stage
  relays
• All the 1 stage options were more expensive
• 140 mm 1st stage appears to be the lowest cost
  and risk
• Summary in KAON 628
• Possible savings by eliminating switchyard
• ROM quotes on dichroics in progress now
• Effect on emmissivity at K-long (key issue) is
  not resolved need input on IFU pickoff and MEMS
  relay design
• Floating idea of no MEMS in the IFU path. Severe
  impact on encircled energy requirement expected.
  KAON 471, Dons presentation at SD Team Meeting
  4.
• Floating idea of no pickoff for IFU saves on
  cost of pickoff and has less emissivity due to
  fewer surfaces

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AO Design Impact - item by item (page 1)

• Single NIR IFU
• Pickoff?
• No PSF monitor DM no TT mechanism on TWFS
• Would require higher quality FSM in 1st relay
  than envisioned
• Reduced laser power
• No impact
• Fix central four LGS beacons
• Eliminates pickoff mechanisms
• Lasers on elevation ring
• No impact
• Single level cascaded relay
• Saves cost of engineering the 2nd level structure
• Re-use DM? I sent a message about this it may
  be possible to work around the hystersis issues
  due to our woofer-tweeter architecture

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AO Design Impacts - item by item (page 2)

• Dont use OSIRIS
• Saves engineering cost of feeding OSIRIS
• No visible imager
• Considerably simplifies the switchyard. The
  IR/Vis switchyard is a very crowded area in the
  cascaded relay layout and has several mechanisms
  for switching observing modes.
• 2 instead of 3 LGS WFS lenslet arrays
• No impact
• No ADC on NGS WFS
• Reduced switchyard opto-mechanics see above on
  OSIRIS and vis imager
• Reduce proj mgmt and sys eng
• Increases risk
• Fewer controlled devices

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AO Design Impacts - item by item (Last page)

• Reduced RTC complexity
• Some savings here most likely only hardware
  costs
• Still need to evaluate
• Higher MEMS costs
• Not a good trend, but customers are paying
• Should try to negotiate a package deal given we
  would be buying multiple MEMS