Download ASTRONOMY PORTFOLIO 2009 Atacama Cosmology Telescope

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ASTRONOMY PORTFOLIO 2009
One of Dynamic Structures' most noted areas of innovation is in helping scientists view the universe millions
of light years away, through the development and building of telescope observatories throughout the world.
Some of the projects we have completed include Keck I and II (the largest ground based telescope in the
world), the Gemini twin observatories on Hawaii and in Chile , the Sir William Herschel and Sir Isaac Newton
facility in the Canary Islands.
For the last 25 years we have served the global astronomical community by providing detailed designs,
manufacturing and on-site construction of enclosures and telescopes. We are Canada 's leading international
designer and builder of telescopes and enclosures for astronomy, and our expertise is considered to be at the
forefront of the industry.
From telescopes ranging in size from 3.5 metres to 10 metres, to the next generation telescopes as large as
30 metres, we continue to provide revolutionary support to the advancement of mankind through astronomical
discoveries.
This document outlines how Dynamic Structures has assisted clients with their unique project requirements
and challenges.
Atacama Cosmology Telescope
Overview
Dynamic Structures was contracted by Princeton
University and the University of Pennsylvania,
funded by the U.S. National Science
Foundation, to provide full turnkey design
through commissioning of the Atacama
Cosmology Telescope (ACT). This unique
cosmology telescope could determine the origin
of the universe.
The six-metre diameter, off-axis, millimeter-wave cosmology (the study of the entire universe) telescope will
be used to study cosmic microwave background radiation – the remnant heat left over from the ‘Big Bang' that
still pervades the universe and is visible to microwave detectors as a uniform glow across the entire sky. The
radiation is composed of mass-less or nearly mass-less particles that move at the speed of light.
Unlike other radio telescopes that look for a faint radio wave source then once found, tracks it, ACT will scan a
patch of sky back and forth millions of times, creating an overlay of information, resulting in an image that can
provide more detailed clues to help resolve the mysteries of the universe. It is the only radio telescope in the
world that can perform this kind of function.
The 71 primary reflector segments make up the primary mirror measuring 6.7 metres. Supported by an
elevation frame and mount structure, the telescope is set inside a bowl-shaped protective ground screen
framing that together measures 40 feet in height.
Dynamic Structures relationship with the scientific community and being the international leader in building
telescope observatories throughout the world was the deciding factor for Princeton University to work with us.
Princeton University felt the team understood the difficulty of the problem, had a good feel for what was
Anything you can dream... We can build. 2
involved and had a good approach as to how to make it work. They just felt Dynamic Structures was the right
group to develop this extremely challenging project.
Challenge
ACT is the first telescope of this size and kind
designed
specifically
to
make
these
measurements. It meets stringent performance,
reliability and quality requirements to attain its
objectives. It needed to be extremely well
defined in terms of position and accuracy. The
plan was to build a drive and control system to
eliminate dynamic errors.
During the project planning stage we were presented
with the challenge of how to design a telescope that
oscillates back and forth, millions of times, while
maintaining its optical performance.
Another part of the design challenge was the fact that
ACT will be sited on the western face of the Cerro Toco
mountain range in the Atacama Desert region of Chile
at an altitude of 5,200 metres. The operating condition
of the telescope is challenged by extreme weather
conditions, including rain, snow, winds up to 145 miles
per hour, and temperatures ranging from minus 20
degrees Celsius to plus 20 degrees Celsius.
Solution
To improve overall telescope performance a
design solution was to use an aluminum
monocoque rather than steel trusses. A
structural analysis comparing aluminum and
steel found that the aluminum solution provided
a lighter structure which produced less impact on
the mechanical components and drives, rigidity,
better thermal performance, and ease of
assembly and disassembly.
The entire telescope structure was assembled at
the Dynamic Structure's plant and put through a
series of tests to ensure it met specifications
before being shipped to Chile and installed.
For more information on ACT visit www.physics.princeton.edu/act/
Anything you can dream... We can build. 3
Canada France Hawaii
Telescope Enclosure
Overview
Dynamic Structures was responsible for designing the first high-altitude telescope
enclosure to be built on Mauna Kea , Hawaii , at an elevation of 13,987 feet, to
house a 3.6 meter equatorial telescope. This was the first telescope enclosure we
had ever designed and built.
Challenge
We needed to design an enclosure that would be structurally secure during all phases of construction, and
would protect a sophisticated telescope both thermally and dynamically while at the same time also resisting
high survival wind loads and temperature swings.
Solution
During the initial concept phase we considered all the details that would influence risk, safety and cost. We
then designed the structure in such a way that it was simple to construct using jigs and fixtures to position
critical sections of the structure prior to welding. The symmetrical erection sequence we created ensured that
the structure was stable at all times and able to withstand 200 km/h winds.
Outcome
By combining sound practical design solutions with engineering ingenuity we produced an enclosure that
compliments the Canada France Hawaii Telescope. It has been in operation for over 22 years and still ranks
as one of the most advanced telescopes on earth. Its contribution to astronomy has been legendary. Many of
the sophisticated scientific instruments deployed on this telescope were designed and manufactured by the
National Research Council of Canada's Herzberg Institute of Astrophysics (NRC-HIA) in Victoria , Canada .
Canada France Hawaii
Telescope Structure
For more information on CFHT see
http://www.cfht.hawaii.edu/
Overview
Dynamic Structures was responsible for dismantling the Canada France Hawaii Telescope, which had been
manufactured in La Rochelle, France, and shipping it to Hawaii for reassembly within the already constructed
enclosure.
Challenge
We needed to erect the telescope components by lifting them through the enclosure shutter opening, a task
that required massive mobile equipment, and this equipment was not available anywhere in Hawaii . Even if it
were available, it would have been impossible to negotiate the road to the summit.
Solution & Outcome
We designed special erection equipment to handle the large telescope components up the freight elevator
and on the observation floor. We used an overhead crane, specifically designed with the ability to manipulate
components to a high degree of dimensional accuracy, for the final precision assembly onto the telescope
pier. Our attention to detail, coupled with the development of a comprehensive erection plan and the use of
our unique erection aids, allowed this project to be on time and within budget.
Anything you can dream... We can build. 4
Gemini Enclosures
Overview
Dynamic Structures was responsible for detailing,
designing, manufacturing and constructing two state-ofthe-art enclosures to house the two 8-meter Gemini
telescopes, one of which was constructed on Mauna
Kea in Hawaii and the other in Chile .
Challenge
As telescopes get larger it becomes more challenging to
protect them from the environment. To ensure thermal
stability of a telescope structure and its components, it
is necessary to hold an enclosures internal temperature within very fine limits during daylight hours. Before
the telescope is operational, it is desirable to create a thermal balance by allowing ambient air to circulate
around the telescope structure, thereby purging the enclosure. During this phase, the telescope should be
exposed to as much nighttime air as possible. The challenge was to design an enclosure structure that could
protect the telescope during the day yet open up during the night to allow purging.
Solution
We designed large vent shutter doors, which exposed
40% of the enclosure surface, to open and allow
ambient air to encircle the telescope structure and
assist in the purging process. The doors were
manufactured using both aluminum and fiberglass to
protect against high degrees of solar radiation. To
minimize driving loads and gravity effects, the upper
and lower shutters were mechanically connected.
Special stainless steel and teflon bearings formed the
vertical tracks. The enclosure structure was designed to
support these large openings while preserving stiffness
and stability.
Outcome
By continually working with astronomers, scientists and engineers to
find better solutions we enhanced instrument performance. The
venting systems allow the telescopes to be brought online faster,
allowing them to spend more time pointing toward the night sky. Both
Gemini telescopes have produced remarkable images, comparable to
those of Hubble, which proves the success of this design.
For more information on GEMINI
see http://www.gemini.edu/
Anything you can dream... We can build. 5
Sir William Herschel
Telescope Enclosure
Overview
The Sir William Herschel Telescope Enclosure, designed and built for the Science and Engineering Research
Council of the U.K. , offered many logistical challenges as it was built on a remote site on the Island of La
Palma . The 4.2-meter telescope was the last telescope built using conventional primary mirror technology.
Large mirrors require large telescope structures to move them, and these big structures have large thermal
time constants, so the enclosure that surrounds them have to be designed to protect the telescope thermally.
Challenge
The 600-ton enclosure structure continually tracks in azimuth as the telescope moves across the night sky so
high manufacturing precision is necessary to ensure the enclosure runs smoothly, as do the shutter doors
when they open and close to protect the telescope against wind. Our challenges were to design a large,
movable structure that could be constructed on this remote site, and to design insulation and venting systems
that could be manipulated with a changing environment.
Solution
Special self-steering bogies, with the ability to re-adjust their tracking as they moved off theoretical position,
were designed to support the 600-ton structure. This feature allowed the enclosure structure to move
thermally without imposing large radial loads into the lower supporting structure.
A continuous insulation skin placed on the inside of the dome reduced the solar radiation that entered the
enclosure, and large purging fans removed warm air from the space between the outer shell and the read of
the insulation skin. By carefully managing the thermal control system it was possible to hold the internal
temperature to within +/- 1 degree F of the anticipated nighttime temperature.
A special crane was designed
to handle both the enclosure
and telescope components. It
was shipped to the site in
containers
and
manually
erected on-site using hand
winches.
Outcome
The Sir William Herschel
Telescope
continues
to
provide valuable support to the
astronomical
community.
Many of the design features
developed
for
both
the
telescope and enclosure are
still being used in today's
state-of-the art instruments.
For more information on
WILLIAM HERSCHEL see
http://www.ing.iac.es/PR/wht_info/
Anything you can dream... We can build. 6
W. M. Keck Telescope Enclosure
Overview
Dynamic Structures was responsible for designing enclosures for
the twin Keck 10-meter telescopes to be constructed on the
Mauna Kea summit, at a 13,978 ft. elevation, on the island of
Hawaii.
Challenge
These telescopes are presently the largest ground-based telescopes on earth. To move forward with the
enclosures, new design approaches were required. Our engineers had to understand and shape the designs
around the mandate of protecting the telescopes thermally and dynamically.
Solution
We used experience gained in constructing other enclosures as the fundamental building block for the basic
design. To minimize the enclosure diameter and thus thermal inertia, a new style of up-and-over shutters was
designed. Bogies that support the 750-ton structure were designed to be self-steering in order to compensate
for thermal changes in the enclosure shape.
Outcome
The Keck twin telescopes have high-precision instruments resulting from the very best creative thinking in all
aspects of design and construction, and continue to be the world's cutting-edge telescopes. Many incredible
astronomical discoveries have been made possible because of these telescopes.
For more information on KECK-II see
http://www.keckobservatory.org/
W.M. Keck II Telescope
Overview
Dynamic Structures was responsible for detailing, designing, manufacturing, and constructing the world's
largest optical telescope.
Challenge
The twin Keck 10-meter telescopes are presently the largest
ground-based telescopes in the world. The telescope structure,
optical modules and segmented mirrors demanded design
solutions and manufacturing precision that pushed many
frontiers. Our challenge was to work with astronomers,
scientists and engineers to find the best-engineered solution. In
addition, due to the high elevation at the summit of Mauna Kea ,
workers powers of reasoning and physical ability are seriously
affected when working at this high altitude.
Anything you can dream... We can build. 7
Solution
Working with an existing structural solution, we developed new detail
solutions for structural connections aimed at minimizing joint
eccentricity. One of the most critical telescope components is the mirror
cell, a space frame structure made up of over 500 individual members.
This structure was manufactured in modules and assembled in the
inverted position. Superposition of the nodes during assembly ensured
that once the structure was mounted, with all actuators and mirrors in
place within the telescope, structural deflection was within one
millimetre. Before shipment to site, the entire telescope was assembled
and tested for compliance. The azimuth journal, the precision steel rail
that the telescope rotates on, was manufactured in segments and
shipped to the site for final welding. Special joints were designed to minimize welding distortion and control
surface accuracy. With welding completion, custom designed grinding equipment feathered the joints to
micron accuracy. To deal with construction at this high altitude, unique erection aids coupled with a detailed
operational plan were fundamental to allowing this project to be on time and within budget.
Outcome
The Keck telescopes continue to be the world's leading edge telescopes. Many incredible astronomical
discoveries have been made possible through the use of these twin telescopes. They are high precision
instruments that demanded the very best in creative thinking in all aspects of design and construction.
Attention to detail and the development of the overall plan proved to be invaluable.
For more information on KECK-II see
http://www.keckobservatory.org/
Owens Valley Radio Observatory
Overview
The Owens Valley Radio Observatory (OVRO) is the largest university-operated radio astronomy observatory
in the world, and is located near Bishop, California, approximately 400 km (250 miles) north of Los Angeles on
the east side of the Sierra Nevada. Dynamic Structures was contracted by the California Institute of
Technology to manufacture and assemble three high precision mounts that would allow smooth and accurate
positioning of a 12-meter diameter radio antenna dish. Each antenna mount included a drive control system
for positioning the antenna in both azimuth and elevation axis.
Challenge
Each drive mount is assembled from a group of machined fabrications, and these fabrications have to be
machined to close tolerances relative to geometric datums. It was extremely important that the main bearing
locations and drive mechanisms be accurately positioned. The off-axis loading requires that the drive mount
be extremely rigid but also allow smooth accurate rotation in both axis.
Solution
All of the weldments were fabricated to close tolerances and then thermally stress relieved prior to machining.
All machining was performed on the completed weldment and this included the trunnion mount and main
azimuth bearing support. To ensure concentricity of the azimuth bearing ring, the inner cone weldment and
Anything you can dream... We can build. 8
bearing ring were pre-assembled and finish ground as a unit. The elevation trunnion mount bearing diameters
were also machined at the same setting to ensure parallelism and concentricity.
Outcome
Each antenna mount was completely assembled and tested prior to
shipping. The drive controls on both the azimuth and elevation were
powered up to simulate normal operation. The alignment, accuracy
and rotation of all moving parts was checked and found to be well
within the specification requirements for antenna operation.
For more information on OVRO see
http://www.ovro.caltech.edu/
Sir Isaac Newton
Telescope Enclosure
Overview
The Sir Isaac Newton Telescope Enclosure, designed and built for the Science and Engineering Research
Council of the U.K., was created to house a 2.5-meter polar axis telescope that had been operating in the
south of England. The telescope was modified and moved to the Island of La Palma . Dynamic Structures was
contracted to design and construct the telescope enclosure.
Challenge
The original enclosure was constructed of aluminum and used bi-parting shutters to open the telescope to the
night sky. It was thermally and dynamically inadequate for the new site, so a new enclosure had to be
designed to enhance the telescopes performance.
Solution
The new design concept moved away from bi-parting shutters to an up-and-over split shutter concept. This
solution allowed the telescope top end to be protected as the telescope moved in elevation and azimuth. By
moving the shutter components in unison the opening could be controlled to a minimum rectangular size. We
designed the bottom shutter to independently lower from the closed position allowing the telescope to point to
horizon.
Outcome
Our new shutter design concept became the universal standard. It provided better environmental protection
for the telescope by reducing enclosure size and improving weather sealing. Our new approach to
manufacturing, plus on-site construction, made this structure extremely cost-effective.
For more information on ISAAC NEWTON see
http://www.ing.iac.es/PR/int_info/
Anything you can dream... We can build. 9
Starfire Enclosure
Overview
The Starfire Optical Range at Kirkland Air Force Base did significant classified work in the 80's by developing
adaptive optical technology to overcome the "seeing" limitations of large optical telescopes. A large amount
of optical turbulence may be removed by using an artificial star, produced by a laser, to probe the atmosphere
and produce an error signal that can be used to "modulate" one of the telescopes mirrors. Dynamic
Structures was contracted to design and build a very special enclosure to house this unique telescope.
Challenge
Any structure that surrounds a telescope during operation creates a thermal footprint that can significantly
affect image quality. Our challenge was to design a non-conventional enclosure, one that was virtually
invisible thermally and dynamically, to protect the telescope when not in use.
Solution
The lightweight enclosure we designed was constructed from aluminum to reduce thermal mass. The
enclosures inner walls were ducted to allow refrigerated air to pass through the interface. An ice plant was
constructed to service the cooling of the enclosure. To eliminate any dynamic disturbance, the enclosure
structure was isolated from the telescope structure. Unlike conventional enclosures which rotate with the
telescope during observation, this structure was designed to lower in sections. Once lowered, the telescope
could move unrestricted in both azimuth and elevation. With the telescope completely exposed thermal
performance was greatly improved.
Outcome
The Starfire facility developed adaptive technology to a level where it is now considered an essential
component to be added to the next generation of large optical telescopes. Ground-based telescopes using
this technology can now produce images that are equivalent to images created by the Hubble Space
Telescope. We were instrumental in designing and manufacturing an enclosure that made this possible.
Feasibility / Research
Dynamic Structures has been involved in a number of feasibility studies. We lead the investigation and try to
clearly establish whether a project will work and achieve its expected results. Such a study usually evaluates
in detail a project's technical design, its costs and benefits, social and environmental aspects, institutional
issues, financial aspects, etc. Feasibility studies are usually carried-out in the preparation stage of the project
cycle
www.empireds.com
Anything you can dream... We can build.