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ATACAMA. CCAT : The Cornell-Caltech Atacama Telescope. A joint project of Cornell University, the California Institute of Technology and the Jet Propulsion Laboratory. Riccardo Giovanelli. Guiding Principles Scientific Excellence Institutional Synergy
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ATACAMA CCAT : The Cornell-Caltech Atacama Telescope A joint project of Cornell University, the California Institute of Technology and the Jet Propulsion Laboratory Riccardo Giovanelli
Guiding Principles • Scientific Excellence • Institutional Synergy • Special Niche/High Visibility • Ride the technology wave of large • format Bolometer Arrays • At the best possible, easily • serviceable Earth location • High synergy with (and enabler to) • ALMA
CCAT • A unique project geared towards the investigation • of cosmic origins, from planets to galaxies, in the • FIR/submm niche; • with a focus that emphasizes our institutions’ • instrument building talents & development of • forefront technologies; • that can sensibly achieve first light by 2012; • that will maintain the US in the forefront of research • in one of the most rapidly developing observational/ • technological fields; • that will provide strong opportunities for • synergistic science with ALMA; • at cost affordable by a small consortium of academic • institutions.
The CCAT: • A 25m-class FIR/submm telescope that will • operate with high aperture efficiency down • to l = 200 m, an atmospheric limit • Able to accomodate large format bolometer • array cameras (large Field of View ~20’) and • high spectral resolution heterodyne receivers • At a very high (elevation > 5000m), very dry • (Precipitable Water Vapor column PWV<1 mm) • site with wide sky coverage
Science Areas: • Early Universe Cosmology • Galaxy Formation & Evolution • Disks, Star & Planet Forming Regions • Cosmic Microwave Background, SZE and • Solar System Astrophysics Major Science Role: Large Scale Surveys (galaxies, debris disks, KBOs), feeder to ALMA
How did we get from this: … and this? …to this: … and this
Brief technical specs: • f/0.6, very large FOV • Better than 10 micron total budget • Conventional mount design • In a dome • Active primary control • Subarcsec pointing & tracking
Full 20’ x 20’ FOV See G. Cortes paper at July Midterm Review
Mountain Facility: Observing Level M3Engineering & Technology Corporation
Mountain Facility: First Level Plan M3Engineering & Technology Corporation
Mountain Facility: Second Level Plan M3Engineering & Technology Corporation
Mountain Facility: Building Section M3Engineering & Technology Corporation
Mountain Facility: Exterior M3Engineering & Technology Corporation
Update: Reports from Contractors • Several Final Reports Received • AMEC Dome Study Report • All Three Panel Study Reports (CMA, Xinetics, ITT) • Laser Metrology (JPL) • Pending • M3 Architectural Study, Vertex RSI Mount Study • Calibration WFS Study, Systems Engineering • Science & Requirements Report, Instrumentation Report • M2/M3 Report (CSA Engineering) • others
Central Mount Steel Normal and Uplift Rollers Normal Pivot Bearing Bogie Frame Polyurethane Radial Roller Concept Updates • Dome Concept • Structure Further Developed • Shutter Approach Illustrated • Mechanisms Further Designed • Cost Estimate • ~$13m • Consistent with Allocated Cost
Aperture Ring CAP Interface Ring BASE Azimuth Ring Zen=00 Zen=150 Zen=300 Zen=450 Zen=600 Zen=750 Calotte Enclosure Concept
Structural Design and Analysis Element Plot • General design • Steel triangulated frame structure • Stiffened ring sections at mechanical interfaces • Structural Analysis • Preliminary FEA of all-steel enclosure • Members optimized under survival load combinations (gravity, wind, snow, ice) • Mechanical interfaces modeled with equivalent spring stiffnesses • Total Enclosure Mass • Base structure: 140 tonne • Cap structure: 120 tonne • Shutter structure: 50 tonne • Cladding/Girts: 80 tonne • Azimuth mechanical: 50 tonne • Calotte mechanical:25 tonne • TOTAL: 465 tonne Gravity Deflections ~7mm max
Concept Updates • Mount Developments • CAD Model Further Developed • Truss Added • Mass Estimated • Mount Cost Not Yet in Hand • Control Analysis Indicates that Mount Will Probably Meet Scanning/Pointing Requirements
PM Study Point Design • Segmentation • 6 Annular Rings • Segments Max 2m x 2m • Wide Latitude in Design • Facilitates Replication • Only 6 Different Types • Size Compatible With Several Manufacturing Techniques
Three Panel Studies In Work • Composite Mirror Applications, Tucson, AZ • Al Sandwich • Successfully Used by MAN for SMT, Achieving 14 µ RMS • Low CTE, High Specific Stiffness • Xinetics Inc., Devens, MA • Nanolaminate Front Shell (LLNL Technology) • Laminated to SiC Lightweighted Support Structure • Proprietary Casting/Sintering Process • ITT Industries, Rochester, NY (Former part of Kodak) • Borosilicate Glass Forming • Proprietary Process for Forming Lightweight Core Between Face and Back Sheets
Concept Updates • Mirror Segments • Xinetics (SiC) Provides a Good Study but Cost is >>> Than Acceptable • ITT and CMA Complete Studies • Both Have Feasible Designs • Both Costs Somewhat Higher than Target • Reasonable Way Forward with Both
Corrugated Mirror Assemblies Fuse top and bottom plates to corrugated core (1 day) Lightweighting efficiently stiffens face sheets.
Corrugated Mirror Benefits Total process time per panel is short (~1 week) Benefit: High production rates, low cost per panel Areal densities below 10kg/m² have been demonstrated Benefit: Meets system requirements for overall weight Inexpensive raw material Benefit: Low cost per panel Several design approaches Benefit: Adequate trade space for design optimization Traditional mirror materials plus innovative manufacturing processes can meet the cost , schedule, and technical requirements of CCAT
Submm Camera • Strawman First light instrument • FOV • Nyquist sampling a 5’x5’ FOV at 350 m: 170 170 pixel array • 30,000 pixels, or 6 times that of SCUBA-2 • Primary bands • 200, 350, 450 m and 620 m • Driven by similar backgrounds and adequate sampling requirements • Filter wheel to change wavelengths • Telescope designed with ~20’x20’ FOV; future instruments will take advantage of the entire FOV
Study Report • Study Report in Work • First Draft Book Assembled • Process for Review & Revision Defined • Target is to Go to Print in Mid December • Study Review in preparation (Jan 2006)
Site In the highest, driest tropical region on Earth … at an elevation of ~18,000 ft a.m.s.l. (as high as you can drive a truck), in the Atacama region of Northern Chile, it will be the highest observatory on Earth.
Sairecabur Toco ACT JNAO Chajnantor MPI Chico Chascon ALMA CBI Negro National Science Preserve (managed by CONICYT) Honar
Sub-mm Atmospheric Transmission Atmospheric transmission for different amounts of precipitable water vapor. The horizontal red bars represent the adopted bandpasses and the average transmission for 0.25 mm PWV.
C. Chajnantor View to North View to the South
Possible site (5575m) Summit (5655m)
Spring 2003 : Partnership initiated • October 2003: Workshop in Pasadena • Feb 2004: MOU signed by • Caltech, JPL and Cornell • Late 2004: Project Office established, • PM, DPM hired, • Study Phase pace accelerates • July 2005: Study Phase Midterm Review • Early 2006: Preliminary CDR • 2006-2008 Engineering Design Phase, • finalize Site Selection • 2008-2012 Construction and First Light Project Status
Estimated Construction Cost $100M (includes 1st light instrumentation) Estimated cost of operations ~$5M/yr (excludes intrument upgrade and development) Estimated cost of Instrument Upgrade & Development ~$1.5-2M/yr