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

NGAO Build to Cost SummaryNGAO Build to Cost Summary

Peter Wizinowich, Sean Adkins, Rich Dekany, Peter Wizinowich, Sean Adkins, Rich Dekany, Don Gavel, Claire Max & the NGAO TeamDon Gavel, Claire Max & the NGAO Team

SSC MeetingSSC MeetingApril 14, 2009April 14, 2009

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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: NgaoSDR)

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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

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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

Science PrioritiesScience Priorities

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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.

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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

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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

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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)

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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 nm7. Visible imager & IFU to shorter 8. Deployable multi-IFS instrument (removed from plan)

– Ranked as low priority by Keck SSP 2008 & represents a significant cost

Included in B2CExcluded

AO Design Changes AO Design Changes to Support Build-to-Costto Support Build-to-Cost

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

X

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Revised NGAO System ArchitectureKey Changes:1. No wide field science instrument • Fixed narrow field tomography• TT sharpening with single LGS AO• 75W instead of 100W• Narrow field relay not reflected2. Cooled AO enclosure smaller3. Lasers on elevation ring4. Combined imager/IFU instrument & no OSIRIS5. Only one TWFS

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AO Design Changes Summary

A. Architectural changes allowed by no deployable multi-IFS instrument1. LGS asterism & WFS architecture2. Narrow field relay location

B. New design choices that don’t impact the requirements1. Laser location 2. AO optics cooling enclosure

C. Design choices with modest science implications1. Reduced field of view for the wide field relay (120” vs 150” dia.)2. Direct pick-off of TT stars3. Truth wavefront sensor (one visible instead of 1 vis & 1 NIR)4. 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, 9x smaller tomography volume

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Performance Analysis Summary• “3+1” science asterism + 3 pointable lasers has excellent

performance for narrow field science

• Overall performance comparable to estimates at SDR Science

BandStrehl Ratio

Ensquared Energy

Effective WFE (nm)

Ensquared Energy

Gal Center imaging (1" off-axis) 188 1.4 189 K 75% 184Exoplanets 162 3.3 171 H 65% 157Minor Planets 162 4.3 177 z 20% 175Galaxy Assembly 162 7 204 K 71% in 70 mas 257 55% in 70masNearby AGN 162 5 182 z 24% in 34 mas

Performance at SDR

Science Case

Science PerformanceHigh order wavefront error (nm)

Tip-Tilt error (mas)

Effective wavefront error (nm)

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Wavefront Error versus Laser Power

50W in science asterism

50W +median Na

density

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Strehl Ratio versus Laser Power

50W in science asterism

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EE70mas and Tip-Tilt Error vs. % Sky Coveragefor Galaxy Assembly case, median seeing

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EE70mas and Tip-Tilt Error vs. % Sky Coveragefor Nearby AGN case, median seeing

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Strehl Ratio and Tip-Tilt Error vs. % Sky Coverage for Exoplanets case, median seeing

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Strehl Ratio and Tip-Tilt Error vs. % Sky Coverage for Minor Planets case, median seeing

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Performance versus Sky Coverage

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% EE (70 mas)

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EE70mas and Tip-Tilt Error vs. % Sky Coveragefor Galaxy Assembly case, median seeing

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EE70mas and Tip-Tilt Error vs. % Sky Coveragefor Nearby AGN case, median seeing

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Strehl Ratio and Tip-Tilt Error vs. % Sky Coverage for Exoplanets case, median seeing

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Strehl Ratio and Tip-Tilt Error vs. % Sky Coverage for Minor Planets case, median seeing

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Performance versus Sky Coverage

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Off-axis Performance

Median seeing

Max. IFU radius

Max. imager radius

Imaging radius requirement

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Science Instrument Design Changes

• NGAO Proposal had three science instruments ($20M in FY06 $)– 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)

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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 NIRC2

• Single plate scale– selected to optimally sample the diffraction limit, e.g. /2D 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

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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. /2D 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

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OSIRIS role replaced by new IFS• Carefully reviewed OSIRIS role

– In consultation with Larkin & McLean• 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 K1

• NGAO cost savings & design freedom in not having to implement OSIRIS

Impact on Science RequirementsImpact on Science Requirements

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Impact on ability to meet Science Requirements

Key Science Driver SCRD Requirement Performance of B2C

Galaxy Assembly(JHK bands)

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.

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

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B2C Design Changes: only modest effect on meeting science requirements

• Galaxy Assembly: B2C exceeds SDR requirements

• Nearby AGNs: B2C 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 B2C design changes. Static errors dominate.

• Multiplicity of minor planets: Meets SDR requirements√

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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 1st science– Key community resource in support of TMT science (do at Keck 1st 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)WMKO NGAO JWST

Diffraction-limit (mas) at 2 m 41 63Diffraction-limit (mas) at 1 m 20 limited by samplingSensitivity 1x ~200x@K; ~1/6x@JImager NGAO Imager NIRCam IRIS Imager IRMS

Detector H4RG 4x H2RG H4RG H2RGWavelength range (m) 0.8-2.4 0.6-2.35 0.8-2.5 0.8-2.5Sampling (mas/pixel) 8.5 31.7 4 60FOV (arcsec) 35 130 15 120

Spectrometer NGAO IFS NIRSpec IRIS IFS IRMSDetector H4RG 2x H2RG H4RG H2RGWavelength range (m) 0.8-2.4 0.6-2.35 0.8-2.5 0.8-2.5

Spectral Resolution R~4000

R~100 & ~1000 multi-object modes

R~3000 IFU or long-slit modes

Two image slicers; R~4000

R=3270 (0.24" slit)R=4660

(0.16" slit)Spatial Resolution (mas) 10, ~25 & ~60 ~100 4 to 50 160

FOV (arcsec) 0.8, 2 & 4200 FOR

4 slit; 3x3 IFU up to 3 120 FORProjected 1st science paper ~2015 ~2014

TMT NFIRAOS147

~2020

~80x

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NGAO comparison to JWSTEvaluation of key science cases:

Key Science Case JWST & NGAO

Galaxy Assembly (JHK)

JWST much more sensitive at K.NGAO sensitivity higher between OH lines at H.NGAO sensitivity higher for imaging & spectroscopy at J.NGAO wins in spatial resolution at all .NGAO provides higher spectral resolution.

Nearby AGNs (Z) Only NGAO provides needed spatial resolution (especially at Ca triplet).

General Relativity at Galactic Center (K)

Only NGAO provides needed spatial resolution (especially important to reduce confusion limit).Long term monitoring may be inappropriate for JWST.

Extrasolar Planets around old Field Brown Dwarfs (H)

Only NGAO provides needed spatial resolution.JWST coronagraph optimized for 3-5 m, >1"; NGAO competitive ≤2 m, <1".

Multiplicity of Minor Planets (Z or J) Only NGAO provides needed spatial resolution.

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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 TMTKey Science Case TMT & NGAO

Galaxy Assembly (JHK)

NGAO & TMT have the same spatial resolution with ~20 & 50 mas IFUs, but TMT has higher sensitivity.NGAO may do most of Z < 2.5-3 targets either before TMT or because of scarce TMT time.

Nearby AGNs (Z)NGAO will screen most important targets. With 3x higher spatial resolution TMT will detect smaller black holes.

General Relativity at Galactic Center (K)

TMT wins in spatial resolution, sensitivity less important. Significant value in continuing NGAO astrometry into TMT era (MCAO field stability concern; Keck access easier).NGAO synoptic advantage.

Extrasolar Planets around old Field Brown Dwarfs (H)

TMT spatial resolution an advantage.Control of static wavefront errors & PSF characterization will be critical (NGAO will have 5 year head start on experience).NGAO synoptic advantage.

Multiplicity of Minor Planets (Z or J)

TMT spatial resolution an advantage; NGAO could move to shorter . Much of this science may be done before TMT?NGAO synoptic advantage.

Revised Cost EstimateRevised Cost Estimate

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Revised Cost EstimateIncluding all proposed cost reductions & new cost estimates:

NGAO System FY07 FY08 FY09 FY10 FY11 FY12 FY13 FY14 FY15 TotalSystem Design 739 495 1234Preliminary Design 214 1240 1492 2946Detailed Design 1600 5500 978 8078Full Scale Development 400 500 7415 8715 5262 22293Delivery & Commissioning 1764 1825 3589Contingency (24%) 466 1741 3014 3119 611 8951

NGAO Total = 739 709 1240 3958 6000 10134 11729 10145 2436 47090IFS Design 51 229 78 358Imager and IFS Instrument 123 443 4284 4264 486 12 9613Contingency (10/30%) 17 67 1309 1279 146 4 2822

NGAO Instrument Total = 192 739 5670 5544 632 15 0 12793Overall Total = 739 709 1432 4697 11670 15678 12361 10161 2436 59883

Actuals ($k) Plan (Then-Year $k)

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Revised Cost Estimate

• Cost estimation methodology approved at SDR• NFIRAOS comparison improved confidence in estimate• Revised estimate incorporates new information

– IFS design (ATI) & K2 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 (NIRC2, OSIRIS,

MOSFIRE, IRIS)

– 30% contingency assumed post-design

Assessment of Build-to-Cost Review Assessment of Build-to-Cost Review Deliverables & Success CriteriaDeliverables & Success Criteria

+ Conclusions+ Conclusions

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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

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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

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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 B2C 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