ATACAMA

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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
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• 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

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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.

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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 gt 5000m), very dry
• (Precipitable Water Vapor column PWVlt1 mm)
• site with wide sky coverage

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• 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
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How did we get from this
and this?
to this
and this
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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

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Full 20 x 20 FOV
See G. Cortes paper at July Midterm Review
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Mountain Facility Observing Level
M3 Engineering Technology Corporation
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Mountain Facility First Level Plan
M3 Engineering Technology Corporation
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Mountain Facility Second Level Plan
M3 Engineering Technology Corporation
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Mountain Facility Building Section
M3 Engineering Technology Corporation
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Mountain Facility Exterior
M3 Engineering Technology Corporation
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(No Transcript)
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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

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Concept Updates

• Dome Concept
• Structure Further Developed
• Shutter Approach Illustrated
• Mechanisms Further Designed
• Cost Estimate
• 13m
• Consistent with Allocated Cost

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Calotte Enclosure Concept
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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
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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

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CCAT Mount Overview
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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

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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

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Concept Updates

• Mirror Segments
• Xinetics (SiC) Provides a Good Study but Cost is
  gtgtgt Than Acceptable
• ITT and CMA Complete Studies
• Both Have Feasible Designs
• Both Costs Somewhat Higher than Target
• Reasonable Way Forward with Both

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Corrugated Mirror Assemblies
Fuse top and bottom plates to corrugated core (1
day)
Lightweighting efficiently stiffens face sheets.
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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
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Submm Camera

• Strawman First light instrument
• FOV
• Nyquist sampling a 5x5 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 20x20 FOV future
  instruments will take advantage of the entire FOV
  

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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)

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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.
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Sairecabur
Toco
ACT
JNAO
Chajnantor
MPI
Chascon
Chico
ALMA
CBI
Negro
National Science Preserve (managed by CONICYT)
Honar
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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.
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C. Chajnantor
View to North
View to the South
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Possible site (5575m)
Summit (5655m)
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• 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
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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