1. WMKO Next Generation Adaptive Optics: AO System Design Impact of Cost Savings Ideas Don Gavel December 19, 2008

2. 2 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 1 st 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, Don’s 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

3. 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 1 st 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 2 nd 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 3

4. AO Design Impacts - item by item (page 2) Don’t 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 4

5. 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 5