Multivariable parametric cost models for space telescopes provide several benefits to designers and space system project managers. They identify major architectural cost drivers and allow high-level design trades. They enable cost-benefit analysis for technology development investment. And, they provide a basis for estimating total project cost. A survey of historical models found that there is no definitive space telescope cost model. In fact, published models vary greatly [1]. Thus, there is a need for parametric space telescopes cost models. An effort is underway to develop single variable [2] and multi-variable [3] parametric space telescope cost models based on the latest available data and applying rigorous analytical techniques.
Specific cost estimating relationships (CERs) have been developed which show that aperture diameter is the primary cost driver for large space telescopes; technology development as a function of time reduces cost at the rate of 50% per 17 years; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and increasing mass reduces cost.
KEYWORDS: Space telescopes, Telescopes, Mirrors, James Webb Space Telescope, Data modeling, Systems modeling, Diffraction, Manufacturing, Statistical modeling, Optical instrument design
Parametric cost models can be used by designers and project managers to perform relative cost comparisons between major architectural cost drivers and allow high-level design trades; enable cost-benefit analysis for technology development investment; and, provide a basis for estimating total project cost between related concepts. This paper hypothesizes a single model, based on published models and engineering intuition, for both ground and space telescopes:
OTA Cost ~ (X) D (1.75 ± 0.05) λ (-0.5 ± 0.25) T-0.25 e (-0.04) Y
Specific findings include: space telescopes cost 50X to 100X more ground telescopes; diameter is the most important CER; cost is reduced by approximately 50% every 20 years (presumably because of technology advance and process improvements); and, for space telescopes, cost associated with wavelength performance is balanced by cost associated with operating temperature. Finally, duplication only reduces cost for the manufacture of identical systems (i.e. multiple aperture sparse arrays or interferometers). And, while duplication does reduce the cost of manufacturing the mirrors of segmented primary mirror, this cost savings does not appear to manifest itself in the final primary mirror assembly (presumably because the structure for a segmented mirror is more complicated than for a monolithic mirror).
KEYWORDS: Space telescopes, Databases, Telescopes, Data modeling, James Webb Space Telescope, Systems modeling, Hubble Space Telescope, Space operations, Optical instrument design, Optical engineering
Parametric cost models are an important tool routinely used to plan missions, compare concepts, and justify technology investments. In 2010, the article, “Single-variable parametric cost models for space telescopes,” was published [H. P. Stahl et al., Opt. Eng. 49(7), 073006 (2010)]. That paper presented new single-variable cost models for space telescope optical telescope assembly. These models were created by applying standard statistical methods to data collected from 30 different space telescope missions. The results were compared with previously published models. A postpublication independent review of that paper’s database identified several inconsistencies. To correct these inconsistencies, a two-year effort was undertaken to reconcile our database with source documents. This paper updates and revises the findings of our 2010 paper. As a result of the review, some telescopes’ data were removed, some were revised, and data for a few new telescopes were added to the database. As a consequence, there have been changes to the 2010 published results. But our two most important findings remain unchanged: aperture diameter is the primary cost driver for large space telescopes, and it costs more per kilogram to build a low-areal-density low-stiffness telescope than a more massive high-stiffness telescope. One significant difference is that we now report telescope cost to vary linearly from 5% to 30% of total mission cost, instead of the previously reported average of 20%. To fully understand the content of this update, the authors recommend that one also read the 2010 paper.
KEYWORDS: Space telescopes, Telescopes, Mirrors, James Webb Space Telescope, Data modeling, Optical telescopes, Space operations, Optical instrument design, Astronomical imaging, Optical fabrication
Parametric cost models can be used by designers and project managers to perform relative cost comparisons between
major architectural cost drivers and allow high-level design trades; enable cost-benefit analysis for technology
development investment; and, provide a basis for estimating total project cost between related concepts. This paper
reports on recent revisions and improvements to our ground telescope cost model and refinements of our understanding
of space telescope cost models. One interesting observation is that while space telescopes are 50X to 100X more
expensive than ground telescopes, their respective scaling relationships are similar. Another interesting speculation is
that the role of technology development may be different between ground and space telescopes. For ground telescopes,
the data indicates that technology development tends to reduce cost by approximately 50% every 20 years. But for space
telescopes, there appears to be no such cost reduction because we do not tend to re-fly similar systems. Thus, instead of
reducing cost, 20 years of technology development may be required to enable a doubling of space telescope capability.
Other findings include: mass should not be used to estimate cost; spacecraft and science instrument costs account for
approximately 50% of total mission cost; and, integration and testing accounts for only about 10% of total mission cost.
KEYWORDS: Space telescopes, Telescopes, Data modeling, Optical telescopes, James Webb Space Telescope, Mirrors, Infrared telescopes, Diffraction, Astronomical imaging, Databases
Parametric cost models are used to plan missions, compare concepts and justify technology investments. This paper reviews an on-going effort to develop cost modes for space telescopes. This paper summarizes the methodology used to develop cost models and documents how changes to the database have changed previously published preliminary cost models. While the cost models are evolving, the previously published findings remain valid: it costs less per square meter of collecting aperture to build a large telescope than a small telescope; technology development as a function of time reduces cost; and lower areal density telescopes cost more than more massive telescopes.
KEYWORDS: Space telescopes, Telescopes, Data modeling, Databases, James Webb Space Telescope, Space operations, Systems modeling, Mirrors, Diffraction, Optical instrument design
Parametric cost models are used to plan missions, compare concepts and justify technology investments. This paper
updates an ongoing effort to develop cost modes for space telescopes and summarizes how recent database changes have
changed previously published preliminary results. While the models are evolving, the previously published findings are
valid: telescope cost increases with aperture diameter; it costs less per square meter of collecting aperture to build a
large telescope than a small telescope; lower areal density telescopes cost more than more massive telescopes.
KEYWORDS: Space telescopes, Data modeling, James Webb Space Telescope, Telescopes, Infrared telescopes, Mirrors, Statistical modeling, Mathematical modeling, Databases, Ultraviolet telescopes
Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. This
paper reviews the methodology used to develop space telescope cost models; summarizes recently published single
variable models; and presents preliminary results for two and three variable cost models. Some of the findings are that
increasing mass reduces cost; it costs less per square meter of collecting aperture to build a large telescope than a small
telescope; and technology development as a function of time reduces cost at the rate of 50% per 17 years.
KEYWORDS: Space telescopes, James Webb Space Telescope, Telescopes, Data modeling, Mirrors, Databases, Space operations, Optical engineering, Observatories, Statistical modeling
Parametric cost models are routinely used to plan missions, compare concepts, and justify technology investments. Unfortunately, there is no definitive space telescope cost model. For example, historical cost estimating relationships (CERs) based on primary mirror diameter vary by an order of magnitude. We present new single-variable cost models for space telescope optical telescope assembly (OTA). They are based on data collected from 30 different space telescope missions. Standard statistical methods are used to derive CERs for OTA cost versus aperture diameter and mass. The results are compared with previously published models
KEYWORDS: Space telescopes, Telescopes, Data modeling, Mirrors, Systems modeling, James Webb Space Telescope, Optical telescopes, Infrared telescopes, Statistical analysis, Infrared sensors
Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments.
However, great care is required. Some space telescope cost models, such as those based only on mass, lack sufficient
detail to support such analysis and may lead to inaccurate conclusions. Similarly, using ground based telescope models
which include the dome cost will also lead to inaccurate conclusions. This paper reviews current and historical models.
Then, based on data from 22 different NASA space telescopes, this paper tests those models and presents preliminary
analysis of single- and multi-variable space telescope cost models.
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