Estimating the cost of extremely large telescopes

Abstract

For future giant telescopes, control of construction and operation costs will be the key factor in their success. The best way to accomplish this cost control, while maximizing the performance of the telescope, will be through design-to-cost methods that use value engineering techniques to develop the most cost-effective design in terms of performance per dollar. This will require quantifiable measures of performance and cost, including: (1) a way of quantifying science value with scientific merit functions; (2) a way of predicting telescope performance in the presence of real-world disturbances by means of integrated modeling; and (3) a way of predicting the cost of multiple design configurations.Design-to-cost methods should be applied as early as possible in the project, since the majority of the life-cycle costs for the observatory will be locked in by choices made during the conceptual design phase. However, there is a dilemma: how can costs be accurately estimated for systems that have not yet been designed? This paper discusses cost estimating methods and describes their application to estimating the cost of ELTs, showing that the best method to use during the conceptual design phase is parametric cost estimating. Examples of parametric estimating techniques are described, based on experience gained from instrument development programs at NOAO.We then describe efforts underway to collect historical cost information and develop cost estimating relationships in preparation for the conceptual design phase of the Giant Segmented Mirror Telescope.

Preliminary cost model for space telescopes

“…In 2000, Bely indicated that a scaling law of 2.7 is considered the standard for ground-based observatories [8] and in 2002 Stepp stated that the consensus traditional scaling law appears to be 2.7. [9] While these laws are technically correct, they should not be extended to space telescopes because they all include the ground observatory building and/or dome (the cost of the dome is driven by the volume of the telescope which is proportional to D raised to the 3 rd power). And, space telescopes do not have domes.…”

Spectroscopy and the Age of Giant Telescopes

“…Stepp et al [53] discuss that if one were to extrapolate from the Kitt Peak Mayall 4m to Keck I, the projected cost was 4 times more than the actual cost.…”

“…Construction costs are not, in the end, the dominant cost of telescopes. Over the course of a 30 year lifetime, an intermediate sized telescope (4-10m) will cost two to three times its construction costs [53]. This is estimating the operating costs at 3 to 6 percent of the construction cost of the facility, and doesn't include instrument development.…”

Integrated modeling tools for large ground-based optical telescopes

“…The tilt perturbations are introduced to each segment as a tilt of the parent mirror about its global origin. Tilting about the global origin also results in an inconvenient translation of the segment, as shown in Equation (1).…”

“…1 To simultaneously achieve cost and performance goals, all components of the telescope must be developed as part of an integrated system. The major tools supporting the design and realization of a Thirty Meter Telescope as a system are an integrated computer model capable of predicting the performance of the telescope, a parametric cost estimate capable of predicting the cost of the telescope, and a science merit function capable of linking the engineering performance and the cost of the telescope to the scientific goals and preferences of the relevant astronomical community.…”