The Nancy Grace Roman Telescope (RST) is a NASA observatory designed to unravel the secrets of dark energy and dark matter, search for and image exoplanets, and explore many topics in infrared optics. Scheduled to launch in no earlier than October 2026, this 2.4 meter aperture telescope has a field of view 100 times greater than the Hubble Space Telescope. The mission is currently in its construction phase, where integrated modeling between thermal, structural, and optical models of the observatory is necessary to demonstrate science quality images over the range of operational parameters. This presentation discusses the most recent integrated modeling analysis cycle for Roman, including model correlation with our instrument level testing. We include a discussion on improved processes of the handling of the various flows of data between the modeling disciplines and discipline specific monte-carlo analysis predictions. We will finish with the predicted uncertainties and expected performance for our upcoming observatory alignment verification test using machine learning algorithms.
The Nancy Grace Roman Telescope (RST) is a NASA observatory designed to unravel the secrets of dark energy and dark matter, search for and image exoplanets, and explore many topics in infrared optics. Scheduled to launch in the mid-2020s, this 2.4 meter aperture telescope has a field of view 100 times greater than the Hubble Space Telescope. The mission is currently in its construction phase, where integrated modeling between thermal, structural, and optical models of the observatory is necessary to demonstrate science quality images over the range of operational parameters. This presentation discusses the crosschecks used in the integrated modeling process for RST, including the various flows of data between the modeling disciplines, and summarizes the current predicted performance. Additionally, several optical modeling tools are discussed, along with the specific requirements they are meant to address.
Future large X-ray telescopes will be based on segmented designs and will require different techniques for error analysis
and budgeting from those used for full shell optics. In this paper we develop a grazing incidence optical model using
commercial software Zemax for figure error compensation. In particular we show how the image of a pair of mirror
segments with average radius and/or average cone angle errors can be optimized with rigid body motions such as
pitch, radial despace and axial despace. We show detailed tolerance analysis of the optical model and present results on
how to compensate for these errors up to limitations determined by mechanical constraints of the telescope module.
The International X-ray Observatory (IXO) is designed to conduct spectroscopic, imaging, and timing studies
of astrophysical phenomena that take place as near as in the solar system and as far as in the early universe. It
is a collaborative effort of ESA, JAXA, and NASA. It requires a large X-ray mirror assembly with an
unprecedented X-ray collection area and a suite of focal plane detectors that measure every property of each
photon. This paper reports on our effort to develop the necessary technology to enable the construction of the
mirror assembly required by IXO.
We present an overview update of the metrologic approach to be employed for the segmented mirror fabrication for the
IXO soft x-ray telescope. We compare results achieved to date with mission requirements. This is discussed in terms of
inherent capability versus in-practice capability. We find that all the needed metrology equipment are in hand but that a
number of the needed quantities remain too uncertain relative to mission requirements. This is driven by the mounting
of the mirrors themselves. We then discuss some plans for addressing the mirror mounting issues. Finally, we also
briefly discuss some promising mandrel metrology techniques.
The Solar X-ray Imager (SXI) is a staring grazing incidence X-ray telescope being flown all future GOES
Weather satellites. It provides full solar disc images over the spectral range 10Å < λ < 60Å. Optimizing a
field-weighted-average measure of resolution for this wide-angle application led to a new non-aplanatic
hyperboloid-hyperboloid optical design. A complete systems engineering analysis of the "as-manufactured"
telescope mirrors for the SXI telescope is described. This includes image degradation due to diffraction effects,
geometrical aberrations (from both residual design errors and manufacturing figure errors), surface scatter effects,
all of the miscellaneous errors in the mirror manufacturer's error budget tree, and a rigorous analysis of mosaic
detector effects. Four flight models and a spare of the SXI telescope mirrors have been fabricated. The first of
these SXI telescopes was launched on the NOAA GOES-13 satellite on May 24, 2006. This presentation first
qualitatively illustrates the superb on-orbit performance of the GOES-13 SXI instrument and compares it to the
experimental results from the prototype Wolter Type I instrument on GOES-12. Then quantitative information is
extracted from the raw on-orbit images to provide experimental validation of the computationally intensive image
quality predictions that include both surface scatter effects and detector effects.
Most imaging systems today include a mosaic detector array in the focal plane. Optical designers of astronomical telescopes typically produce a design that yields a superb on-axis aerial image in the focal plane, and detector effects are included only in the analysis of the final system performance. Aplanatic optical designs (corrected for spherical aberration and coma) are widely considered to be superior to nonaplanatic designs. However, there is little merit in an aplanatic design for wide-field applications because one needs to optimize some field-weighted-average measure of resolution over the desired operational field of view (OFOV). Furthermore, when used with a mosaic detector array in the focal plane, detector effects eliminate the advantage of the aplanatic design even at small field angles. For wide fields of view, the focal plane is frequently despaced to balance field curvature with defocus thus obtaining better overall performance. We will demonstrate that including detector effects in the optical design process results in a different optimal (nonaplanatic) design for each OFOV that is even superior to an optimally despaced aplanatic design.
Four flight models and a spare of the Solar X-ray Imager (SXI) telescope mirrors have been fabricated. The first of these is scheduled to be launched on the NOAA GOES- N satellite on July 29, 2005. A complete systems engineering analysis of the "as-manufactured" telescope mirrors has been performed that includes diffraction effects, residual design errors (aberrations), surface scatter effects, and all of the miscellaneous errors in the mirror manufacturer's error budget tree. Finally, a rigorous analysis of mosaic detector effects has been included. SXI is a staring telescope providing full solar disc images at X-ray wavelengths. For wide-field applications such as this, a field-weighted-average measure of resolution has been modeled. Our performance predictions have allowed us to use metrology data to model the "as-manufactured" performance of the X-ray telescopes and to adjust the final focal plane location to optimize the number of spatial resolution elements in a given operational field-of-view (OFOV) for either the aerial image or the detected image. The resulting performance predictions from five separate mirrors allow us to evaluate and quantify the optical fabrication process for producing these very challenging grazing incidence X-ray optics.
Most imaging systems today include a mosaic detector array in the focal plane. Optical designers of astronomical telescopes typically produce a design that yields a superb on-axis aerial image in the focal plane, and detector effects are included only in the analysis of the final system performance. Aplanatic optical designs (corrected for spherical aberration and coma) are widely considered to be superior to non-aplanatic designs. However, there is little merit in an aplanatic design for wide field applications because one needs to optimize some-field-weighted average measure of resolution over the desired operational field of-view (OFOV). Furthermore, when used with a mosaic detector array in the focal plane, detector effects eliminate the advantage of the aplanatic design even at small field angles. For wide fields of view, the focal plane is frequently despaced to balance field curvature with defocus thus obtaining better overall performance. We will demonstrate that including detector effects in the design process results in a different optimal (non-aplanatic) design for each OFOV that is even superior to an optimally despaced aplanatic design.
Most imaging systems today include a mosaic detector array in the focal plane. Optical designers of astronomical telescopes typically produce a design that yields a superb on-axis aerial image in the focal plane, and detector effects are included only in the analysis of the final system performance. Aplanatic optical designs (corrected for spherical aberration and coma) are widely considered to be superior to non-aplanatic designs. However, there is little merit in an aplanatic design for wide field applications because one needs to optimize some field weighted average measure of resolution over the desired operational field of-view (OFOV). Furthermore, when used with a mosaic detector array in the focal plane, detector effects eliminate the advantage of the aplanatic design even at small field angles. For wide fields of view, the focal plane is frequently despaced to balance field curvature with defocus thus obtaining better overall performance. We will demonstrate that including detector effects in the design process results in a different optimal (non-aplanatic) design for each OFOV that is even superior to an optimally despaced aplanatic design.
The Solar X-ray Imager (SXI) is a complimentary, add-on instrument designed for use on the next generation of Geostationary Orbiting Environmental Satellites (GOES). Its primary mission is to continuously observe the full solar disc at X-ray wavelengths; including coronal holes, active regions, flares, and coronal mass ejections. For wide-field imaging applications, there is little merit in an optical design exhibiting stigmatic imaging on-axis; we therefore departed from the classical Wolter Type I design in favor of a hyperboloid-hyperboloid design that balances not only defocus with field curvature but also third-order spherical aberration and astigmatism with oblique spherical aberration. A detailed system engineering analysis including the substantial surface scattering and detector effects indicates that the resulting hyperboloid-hyperboloid design will achieve an 80% increase (over the baseline design) in the number of spatial resolution elements (and hence in total information content in the image) over an 18 arc min radius field-of-view. A comparison of performance predictions with X-ray test data for the SXI Engineering Model is included.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.