Build to Cost Meeting Major NGAO system cost
Build to Cost Meeting: Major NGAO system cost savings ideas Don Gavel NGAO Team Meeting September 11 -12, 2008
Performance Space • Shrink performance along axes to cut costs • Not necessary to cut all axes uniformly • Know the consequence of each reduction Wavelength • Science Impact • Marginal Cost Reduction Strehl • Decide what is a “core” defining NGAO that fits the cost cap and is still worth the cost Sky Coverage Field of View (Regard) Contrast Sensitivity / Throughput / Emissivity Multiplicity of Instruments 2
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 d. IFS multiplicity – one d. IFS? Two d. IFS 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
- Slides: 5