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Thirty Meter Telescope

The Project Manager's Corner: The Past as Precursor
Gary Sanders, TMT Project Manager

January 2006

I want to start 2006 by introducing a monthly column by the TMT Project Manager. My goal is to give you a chance to watch the hectic "going's on" of a project as intense and exciting as TMT. I will pick a highlight each month that is a good story, but also one that signals what we are doing and where we are heading.

I will be a bit more long-winded this month as I tell you of our founding steps in the past two years.

TMT began as a project in June 2003 when the leaders of our three precursor projects (AURA's Giant Segmented Mirror Telescope, ACURA’s Very Large Optical Telescope and CELT's California Extremely Large Telescope) agreed to join the NSF's publicly funded efforts with the traditionally private funded community represented by Caltech and UC. And Canada weighed in with its support and commitment as well, completing the troika.

This was a remarkable move, spanning very different groups in the traditional landscape of astronomy. It was recommended by the U.S. National Academy of Science's most recent decadal survey of astronomy, issued in 2001, the report that identified a thirty meter-class telescope as the highest ground-based astronomy priority for the next decade. The report recognized the high cost and enormous challenge of such an undertaking and called for a joining of public and private astronomy institutions as the best way to marshal the needed resources and talent… but whether anybody would accept the advice was an open question.

The new TMT partners set out to form a centralized project office in Pasadena. I joined TMT in April 2004 fresh from the construction of the Laser Interferometer Gravitational Wave Observatory (LIGO), the first major facility capable of detecting gravity waves from deep space. I was ready for another big challenge. My early focus was working with the partner teams to create an effective organizational structure, and directing a trade study of the three precursor designs to select the single, unified TMT reference design.

This was aided immeasurably by a Science Requirements Document delivered by the TMT Science Advisory Committee and Jerry Nelson, the TMT Project Scientist and veteran of the design of the Keck telescopes on Mauna Kea. This valuable document gave us a science-capability target to structure our design studies toward.

A vigorous "16-week study" that took about 18 weeks in reality culminated in the reference design described elsewhere on these Web pages. It was adopted by the project and blessed by the TMT Board in October 2004.

Our focus turned next to the suite of scientific instruments proposed for the TMT, and their associated adaptive optics systems. Again, our venerable Science Requirements document guided us, and by mid-November 2004, the project was able to adopt an architecture for adaptive optics and science instruments that were designed to take best advantage of the unprecedented number of photons gathered by the vast primary mirror.

The year 2004 finished with key meetings between the project and the industrial firms who have built all of the world’s large commercial telescope mirrors. Our goal was to establish a design for the crucial TMT primary mirror segments that could be produced by industry with a very low cost target for each segment. The two Keck telescopes produced 84 similar segments, including the ones in the telescopes and spares. TMT's comparable number is a superficially imposing 860 segments. We knew that we had to learn, guided by industry, how to make these cheaply and as fast and as good as we need them. This is a job for industrial capabilities, not professors on university campuses. We had numerous face-to-face meetings and spent the 2004 holiday season writing the first bid documents for these mirrors. (Is there a message here? I am writing this during the 2005 holidays!)

The pursuit of our total optical system continued in January 2005 in meetings with industrial suppliers of deformable mirrors, another key component of TMT. Many science applications of the TMT demand a light beam corrected by adaptive optics, and so are very dependent on the ability of these deformable mirrors to deftly change shape in the precise way to cancel the shimmering of Earth’s atmosphere.

TMT issued formal Requests for Information, followed by Requests for Proposals, to all of these suppliers. These led to bidding and signed contracts by the spring. This was the beginning of the large scale industrialization of TMT.

Today, the design and prototype studies set in motion at the beginning of 2005 are yielding design reports and prototype mirrors, with cost estimates for the future, in time for the TMT Conceptual Design Review in May 2006.

The TMT Instruments program was kicked off in February 2005 with release of Requests for Proposals to all significant astronomy instrumentation groups in North America. Our Science Requirements Document gave us good definitions of the instrument features needed for TMT. But the best ideas for obtaining these measurements often come from the specialized groups in astronomy known for clever instrument designs.

TMT reached out in an open competition to groups within the partnership and across the broader community, offering to support initial instrument design studies. For our eight envisioned instruments, TMT received interested responses from 41 groups. These resulted in subsequent mergers and 16 formal proposals.

After extensive peer review, some shuffling and negotiating, a dozen teams are studying the various TMT instruments and their associated adaptive optics systems. Our ongoing dialogues with these groups show that early in 2006, as scheduled, we will be receiving some very good, and innovative, instrument designs.

Our focus turned inward in March toward design work within our team and to planning out the entire design process. Work began on other optics, the telescope enclosure, adaptive optics models and a myriad of related design efforts. A marathon visit to the candidate sites for TMT in Chile and completion of the Mauna Kea site testing permit process signaled a push onto more mountainous terrain—it was easy to dream about a TMT on any of them.

Permission to test the conditions above Mauna Kea was received in April 2005, and mobilization began. Preparation also began on one additional mountain in Chile.

The telescope structure design kicked off in May, as did the design of the crucial segment assembly support units for the primary mirror. We require 860 of these units to support, sense, and move the 860 mirror segments (740 in service at any one time plus spares) and so, again seeking cost efficiency; these are being designed with industry.

The primary mirror control system design was initiated in June. A comprehensive site testing workshop was held with representatives of other large telescope design teams. Adaptive optics modeling received a great deal of attention.

The primary mirror alignment and phasing system design started in July. Those 740 mirror segments must act like one beautiful mirror. This is the system that will make that possible with a push of a button. Our team is the same team that did this wizardry for Keck and showed it could be done.

As August began, four of six candidate mountain sites for TMT had operating robotic observatories collecting data at night. Preparation for the fifth was underway. Requirements for the buildings on the summit and for lower altitude support facilities were aired for the first time. All designs were proceeding apace.

The project came together as a whole in September and saw itself! The month was marked by a big week long "TMT Week" held at the Aspen Center for Physics Ninety scientists and engineers attended, and every part of the TMT effort was presented for discussion, including the work of our instrument partners.

Though we all knew intellectually that work was brisk everywhere, no amount of multi-point videoconferences is as effective as being together face-to-face. Those grainy, jerky backlit faces in all of our daily and weekly review videocons in checkerboard patterns on a TV screen, one head talking after another with electronic slides scrolling across another screen, gave way to a room full of colleagues peppering each other with questions and opining about the really thorny issues. The week went fast and, alas, we left with an even longer list of action items and things to check. September 2005 will be remembered as when the TMT all came together.

With all of the designs progressing, work began in October on formal "bottom-up" cost estimating. No, this stuff won’t be free and the best TMT that we can design is the one we can afford. “Designing-to-cost” is the new mantra. First, we need to get through the sticker-shocks that await us!

The fifth in our set of six mountains came alive in November as the first robotic telescope observations begin on another Chilean peak. Permissions are requested for the sixth and final test site, also in Chile. Designs and planning for the May 2006 Conceptual Design Review loom on the horizon.TMT Poster

Finally, in December, after some debate, we adopted an innovative calotte concept for the TMT enclosure, yielding a cost-effective and technically superior housing for the TMT and all its complex systems. Now we are starting to look at the design of related summit facilities. It feels more real every day.

These are just tidbits. We are moving forward every day, and our accomplishments and emerging challenges during the mountain of effort ahead should make interesting reading.

Stay tuned to this web space for monthly updates on this grand and unique venture.

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Thirty Meter Telescope Project Manager Gary Sanders addresses team members at TMT Week.

The TMT project is a collaboration of Caltech, University of California (UC) and the Association of Canadian Universities for Research in Astronomy (ACURA). © Thirty Meter Telescope


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