NGAO Build to Cost Summary Peter Wizinowich Sean

NGAO Build to Cost Summary Peter Wizinowich, Sean Adkins, Rich Dekany, Don Gavel, Claire Max & the NGAO Team SSC Meeting April 14, 2009

Presentation Sequence • • • Success Criteria, Deliverables & Approach Science Priorities AO Design Changes Science Impact Revised Cost Estimate Assessment of Review Deliverables & Conclusion Build-to-Cost Review Materials (user name & password: Ngao. SDR) 2

Review Success Criteria • The revised science cases & requirements continue to provide a compelling case for building NGAO • We have a credible technical approach to producing an NGAO facility within the cost cap and in a timely fashion • We have reserved contingency consistent with the level of programmatic & technical risk These criteria, plus the deliverables & assumptions, were approved by the Directors & presented at the Nov. 3, 2008 SSC meeting Reviewers found that these criteria were successfully met 3

Cost Reduction Approach • Review & update the science priorities • Review other changes to the estimate (e. g. NFIRAOS cost comparison) • Update the cost estimate in then-year $ • Evaluate the recommended cost reductions – As architectural changes – As a whole including performance predictions • Revise cost estimate • Revisit review success criteria & deliverables 4

Science Priorities

Key Science Drivers Five key science drivers were developed for the NGAO SDR (KAON 455): 1. Galaxy assembly & star formation history 2. Nearby Active Galactic Nuclei 3. Measurements of GR effects in the Galactic Center 4. Imaging & characterization of extrasolar planets around nearby stars 5. Multiplicity of minor planets • We discussed how our recommended cost reductions impact this science. 6

Science Priority Input: SDR Report From the SDR review panel report (KAON 588) executive summary: • • The panel supported the science cases The panel was satisfied with the science requirements flow down & error budget The panel was concerned about complexity (especially the deployable IFS) The panel had input on the priorities – Sky Coverage for NGAO is essential 7

Science Priority Input: Keck Scientific Strategic Plan From the Keck SSP 2008: • • • “NGAO was the unanimous highest priority of the Planetary, Galactic, & Extragalactic (in high angular resolution astronomy) science groups. NGAO will reinvent Keck and place us decisively in the lead in high-resolution astronomy. However, the timely design, fabrication & deployment of NGAO are essential to maximize the scientific opportunity. ” “Given the cost and complexity of the multi-object deployable IFU instrument for NGAO, …, the multi-IFU instrument should be the lowest priority part of the NGAO plan. ” Planetary recommendations in priority order: higher contrast near-IR imaging, extension to optical, large sky coverage. Galactic recommendations in priority order: higher Strehl, wider field, more uniform Strehl, astrometric capability, wide field IFU, optical AO Extragalactic high angular resolution recommendations a balance between the highest possible angular resolution (high priority) at the science & high sensitivity 8

Science Implications of no Multiplexed d-IFU • Galaxy Assembly and Star Formation History – Reduced observing efficiency • Single target observed at a time • Calibrations (e. g. , sky, telluric, PSF) may require dedicated observing sequences – Decreases overall statistics for understanding processes of galaxy formation and evolution • Can be supplemented with complementary HST & JWST results at higher z • General Relativity in the Galactic Center – Decreased efficiency in radial velocity measurements (fewer stars observed at once) • Can gain back some of efficiency hit with a single on-axis IFU that has higher sensitivity (especially for galaxy assembly) & larger FOV (especially for GC) 9

Flowdown of Science Priorities (resultant NGAO Perspective) Based on the SDR science cases, SDR panel report & Keck Strategic Plan: 1. High Strehl • • Required directly, plus to achieve high contrast NIR imaging, shorter AO, highest possible angular resolution, high throughput NIR IFU & high SNR Required for AGN, GC, exoplanet & minor planet key science cases 2. NIR Imager with low wavefront error, high sensitivity, ≥ 20” FOV & simple coronagraph • Required for all key science cases. 3. Large sky coverage • Priority for all key science cases. 4. NIR IFU with high angular resolution, high sensitivity & larger format • Required for galaxy assembly, AGN, GC & minor planet key science cases 5. Visible imaging capability to ~ 800 nm • Required for higher angular resolution science 6. Visible IFU capability to ~ 800 nm 7. Visible imager & IFU to shorter 8. Deployable multi-IFS instrument (removed from plan) – Included in B 2 C Excluded Ranked as low priority by Keck SSP 2008 & represents a significant cost 10

AO Design Changes to Support Build-to-Cost

NGAO System Architecture Key AO Elements: • Configurable laser tomography • Closed loop LGS AO for low order correction over a wide field • Narrow field MOAO (open loop) for high Strehl science, NIR TT correction & ensquared energy X 12

Revised NGAO System Architecture Key Changes: 1. No wide field science instrument • Fixed narrow field tomography • TT sharpening with single LGS AO • 75 W instead of 100 W • Narrow field relay not reflected 2. Cooled AO enclosure smaller 3. Lasers on elevation ring 4. Combined imager/IFU instrument & no OSIRIS 5. Only one TWFS 13

AO Design Changes Summary A. Architectural changes allowed by no deployable multi-IFS instrument 1. LGS asterism & WFS architecture 2. Narrow field relay location B. New design choices that don’t impact the requirements 1. Laser location 2. AO optics cooling enclosure C. Design choices with modest science implications 1. 2. 3. 4. Reduced field of view for the wide field relay (120” vs 150” dia. ) Direct pick-off of TT stars Truth wavefront sensor (one visible instead of 1 vis & 1 NIR) Reduced priority on NGS AO science – Fixed sodium dichroic, no ADC & fewer NGS WFS subaperture scales 5. No ADC implemented for LOWFS (but design for mechanical fit) 6. OSIRIS role replaced by new IFS – Significant reduction in complexity – 37% less motion control, 2 vs 8 dichroics, 9 x smaller tomography volume 14

Performance Analysis Summary • “ 3+1” science asterism + 3 pointable lasers has excellent performance for narrow field science • Overall performance comparable to estimates at SDR 15

Wavefront Error versus Laser Power 50 W + median Na density 50 W in science asterism 16

Strehl Ratio versus Laser Power 50 W in science asterism 17

Performance versus Sky Coverage % EE (70 mas) 1 d Tilt Error (mas) % EE (41 mas) K-band b = 30 18

Performance versus Sky Coverage Strehl Z-band b = 30 19

Off-axis Performance Imaging radius requirement Max. IFU radius Max. imager radius Median seeing 20

Science Instrument Design Changes • NGAO Proposal had three science instruments ($20 M in FY 06 $) – Deployable multi IFS instrument – NIR imager – Visible imager • For the SDR we included OSIRIS integration with NGAO • Science instrument design changes that impact the science capabilities – – – No deployable multi IFS instrument Addition of single channel NIR IFS Removal of OSIRIS (science capabilities covered by NIR IFS) No visible imager Extension of NIR imager & IFS to 800 nm (possibly 650 nm) 21

NGAO Imaging Capability • Broadband – z, Y, J, H, K (0. 818 to 2. 4 µm) – photometric filters for each band plus narrowband filters similar to NIRC 2 • Single plate scale – selected to optimally sample the diffraction limit, e. g. /2 D or 8. 5 mas at 0. 818 µm • FOV – 34. 8" x 34. 8" with 8. 5 mas plate scale • Simple coronagraph • Throughput ≥ 60% over full wavelength range • Sky background limited performance 22

NGAO IFS Capability • Narrowband – z, Y, J, H, K (0. 818 to 2. 4 µm) – ~5% band pass per filter, number as required to cover each wave band • Spectroscopy – R ~4, 000 – High efficiency e. g. multiple gratings working in a single order • Spatial sampling (3 scales maximum) – 10 mas, e. g. /2 D at 1 m – 50 to 75 mas selected to match 50% ensquared energy of NGAO – Intermediate scale (20 or 35 mas) to balance FOV/sensitivity trade off • FOV on axis – 4" x 4" at 50 mas sampling – possible rectangular FOV (1" x 3") at a smaller spatial sampling • Throughput ≥ 40% over full wavelength range • Detector limited performance 23

OSIRIS role replaced by new IFS • Carefully reviewed OSIRIS role – In consultation with Larkin & Mc. Lean • Determined that a new IFS was required by science requirements – Higher sensitivity, higher spatial resolution & larger FOV needed • Minor science benefit to having both new IFS & OSIRIS – Perhaps some plate scales – Perhaps some multiplexing if new IFS deployable (extra cost) • More overall science benefit to continuing to use OSIRIS on K 1 • NGAO cost savings & design freedom in not having to implement OSIRIS 24

Impact on Science Requirements

Impact on ability to meet Science Requirements Key Science Driver SCRD Requirement Performance of B 2 C EE 50% in 70 mas for sky cov = 30% (JHK) EE > 70% in 70 mas for sky cov 90% (K band) √ Nearby AGNs (Z band for Ca triplet) EE 50% in 1/2 grav sphere of influence EE 25% in 33 mas MBH 107 Msun @ Virgo cluster (17. 6 Mpc ) √ General Relativity at the Galactic Center (K band) 100 as astrometric accuracy 5” from GC Need to quantify. Already very close to meeting this requirement with KII AO. √ Galaxy Assembly (JHK bands) Extrasolar planets around old field brown dwarfs (H band) Contrast ratio H > 10 at 0. 2” from H=14 star (2 MJ at 4 AU, d* = 20 pc) Meets requirements (determined by static errors) √ Multiplicity of minor planets (Z or J bands) Contrast ratio J > 5. 5 at 0. 5” from J < 16 asteroid Meets requirements: WFE = 170 nm is sufficient √ 26

B 2 C Design Changes: only modest effect on meeting science requirements √ • Galaxy Assembly: B 2 C exceeds SDR requirements √ • Nearby AGNs: B 2 C doesn’t meet EE requirement (didn’t meet at SDR either). Still in interesting regime for BH mass measurements (MBH 107 Msun @ Virgo cluster). Need to review & more clearly define requirement. √ • General Relativity at the Galactic Center: Key variables (e. g. differential tilt jitter, geometric distortion in AO & instrument, differential atmospheric refraction) not strongly affected by laser power. Confusion only slightly worse than SDR design. √ • Extrasolar planets around old field brown dwarfs: contrast ratio not affected by B 2 C design changes. Static errors dominate. √ • Multiplicity of minor planets: Meets SDR requirements 27

NGAO comparison to JWST & TMT • Higher spatial resolution for imaging & spectroscopy than JWST – JWST much more sensitive at K. NGAO more sensitive at J & between OH lines at H • Lots of NGAO science possible in 5 years prior to TMT 1 st science – Key community resource in support of TMT science (do at Keck 1 st if can) – Could push to shorter or multi-object IFS or … as TMT arrives on scene • NGAO could perform long term studies (e. g. , synoptic, GC astrometry) 28

NGAO comparison to JWST Evaluation of key science cases: 29

NGAO comparison to TMT • NGAO & NFIRAOS wavefront errors are ~ the same (162 vs 174 nm rms) – Similar Strehls but higher spatial resolution for TMT – Similar spatial resolution for IFU science but higher sensitivity for TMT 30

Revised Cost Estimate

Revised Cost Estimate Including all proposed cost reductions & new cost estimates: 32

Revised Cost Estimate • Cost estimation methodology approved at SDR • NFIRAOS comparison improved confidence in estimate • Revised estimate incorporates new information – IFS design (ATI) & K 2 center launch (MRI) proposal estimates – Better laser cost estimates (ESO, GMT, TMT, AURA collaboration) • NGAO contingency has increased from 22. 6% to 24. 2% – Due to increased laser contingency (30% based on NFIRAOS comparison) – Contingency has not been decreased for the reduced complexity – Conservative in reducing labor hours for build-to-cost • NGAO instruments at proposal level – Estimate well anchored to other instrument costs (NIRC 2, OSIRIS, MOSFIRE, IRIS) – 30% contingency assumed post-design 33

Assessment of Build-to-Cost Review Deliverables & Success Criteria + Conclusions

Review Deliverables Summary (1 of 2) • Revisions to the science cases & requirements, & the scientific impact – Galaxy assembly science case & requirements need to be modified for a single IFU instead of multiple deployable IFUs – Only minor impacts on all other science cases • Major design changes – Design changes documented in KAON 642 – Performance impact of design changes documented in KAON 644 • Major cost changes – All cost changes documented with comments & equations in cost book summary spreadsheet by WBS and phase • Viewed as better tool than cost book for tracking changes 35

Review Deliverables Summary (2 of 2) • Major schedule changes – No major schedule changes assumed • 2 month slip in milestones assumed for cost estimate – New plan needs to be developed as part of preliminary design • Preliminary design phase replan is a high priority post this review • Contingency changes – Reviewed contingency as part of NFIRAOS cost comparison • Laser, & potentially RTC, increase identified as needed – Laser contingency increased to 30% – Other bottom-up contingency estimates viewed as sufficient especially given reduction in complexity with design changes 36

Conclusions • The build-to-cost guidance resulted in a simpler & therefore less expensive NGAO facility with similar science performance – Primarily achieved at the expense of a significant science capability (e. g. , the multiple deployable IFS) • We will address the recommendations from the B 2 C review during the preliminary design – And report on how we addressed these recommendations at the PDR • Our management priorities are switching to: – Replanning & completing the preliminary design in a timely fashion – Developing a viable funding & management plan for delivering NGAO in a timely fashion as a preliminary design deliverable 37