Download CCAT - Cornell University

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
M3 Engineering & Technology Corporation
Mountain Facility: First Level Plan
M3 Engineering & Technology Corporation
Mountain Facility: Second Level Plan
M3 Engineering & Technology Corporation
Mountain Facility: Building Section
M3 Engineering & Technology Corporation
Mountain Facility: Exterior
M3 Engineering & 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

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
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M3 Architectural Study, Vertex RSI Mount Study
Calibration WFS Study, Systems Engineering
Science & Requirements Report, Instrumentation Report
M2/M3 Report (CSA Engineering)
others
Concept Updates
Dome Concept



Structure Further
Developed
Shutter Approach
Illustrated
Mechanisms Further
Designed
Cost Estimate


~$13m
Consistent with
Allocated Cost
Central
Mount
Steel Normal and Uplift
Rollers
Normal Pivot Bearing
Bogie Frame
Polyurethane Radial
Roller
Calotte Enclosure Concept
Aperture
Ring
CAP
Interface Ring
BASE
Azimuth
Ring
Zen=00
Zen=150
Zen=300
Zen=450
Zen=600
Zen=750
Structural Design and Analysis
Element Plot
General design


Steel triangulated frame structure
Stiffened ring sections at mechanical
interfaces
Structural Analysis

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
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
140 tonne
120 tonne
50

Base structure:
Cap structure:
Shutter structure:
tonne
Cladding/Girts:
Azimuth mechanical:
Calotte mechanical:

TOTAL:
465 tonne



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80 tonne
50 tonne
25 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
CCAT Mount Overview
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


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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 mm: 170  170
pixel array
 30,000 pixels, or 6 times that of SCUBA-2

Primary bands
 200, 350, 450 mm and 620 mm
 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

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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
Negro
MPI
Chico ALMA
CBI
Honar
Chascon
National Science Preserve
(managed by CONICYT)
Sub-mm Atmospheric Transmission
3
1.0
2 1.5
1.0
0.8
0.6
0.5
Wavelength (mm)
0.4
0.3
0.2
0.9
0.125 mm
0.25 mm
0.50 mm
0.8
1.0 mm
0.25 mm Band Avg
Transmission
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0
200
400
600
800
1000
1200
1400
1600
Frequency (GHz)
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
Summit (5655m)
Possible site (5575m)
• Spring 2003 : Partnership initiated
• October 2003: Workshop in Pasadena
• Feb 2004: MOU signed by
Caltech, JPL and Cornell
Project
Status
• 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
Estimated Construction Cost $100M (includes 1st light instrumentation)
Cumulative and Yearly Spending
Estimated cost of
operations ~$5M/yr
$120.0
$100.0
Estimated cost of
Instrument Upgrade
& Development
~$1.5-2M/yr
Dollars in Millions
(excludes intrument upgrade
and development)
$80.0
$60.0
$40.0
$20.0
$0.0
2005
2006
2007
2008
2009
2010
Calendar Year
2011
2012
2013