Build to Cost Meeting: Major NGAO system cost savings ideas Don Gavel NGAO Team Meeting September 11-12, 2008

Performance Space 2 Strehl Wavelength Sky Coverage Field of View (Regard) Multiplicity of Instruments Sensitivity / Throughput / Emissivity Shrink performance along axes to cut costs Not necessary to cut all axes uniformly Know the consequence of each reduction Science Impact Marginal Cost Reduction Decide what is a “core” defining NGAO that fits the cost cap and is still worth the cost Contrast

Major Cost Savings Scopes Cut Laser Power – by a third?, by one half? –Eliminate wide field d-IFS, concentrate science in 30 arcsec field –6 LGS, 3 roving for point and shoot, 3 are fixed Remove one of the two AO relays –Fewer optomechanical components –Improved throughput –Not split-relay Pare down or eliminate the “switchyard” –Reduced number of instruments –One focal plane (shared for science & LOWFS) –Reduced number of dichroics and changers Reduce automation –Sacrifice “instant” configurability 3

More Cost Savings Scopes Cut number of instruments –Refurbish and reuse OSIRIS –Combined visible/IR sensor in imager –Pare down dIFS multiplicity – one dIFS? Two dIFS with shared dewar? Purchase science imagers from commercial supplier –Live with specs from off-the-shelf design Make the opto-mechanics physically small –Off-the shelf optics and mounts –Smaller space to enclose and cool Cut number of actuators –Trade with other error budget elements to minimize impact –Limiter: short wavelength coverage 4

Even More Cost Saving Scopes Accelerate the project plan –“Then-year” dollars loose value over time (with inflation) –Not necessary to finish earlier, just spend earlier – maybe by overlapping portions of design and FSD phases Reduce technical risk –Targeted prototyping and simulations –Avoid overruns due to rework of uncertainty/untested systems failing to meet expected performance on first implementation 5