A starshade petal error budget for exo-earth detection and characterization

Shaklan, Stuart; Marchen, Luis; Lisman, P. Douglas; Cady, Eric; Martin, Stefan; Thomson, Mark; Dumont, Philip; Kasdin, N. Jeremy

doi:10.1117/12.892834

Cited by 8 publications

(4 citation statements)

References 5 publications

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“…Additionally, the operation of the occulter through varying thermal environments and dynamic loading will inevitably cause variations in the shape. Shaklan et al 4 describe in detail the modeling approach used to develop engineering requirements and determine the sensitivity of the design to errors in manufacture and variations in flight. An optical modeling tool has been developed, described there, that finds the image plane response of the telescope past an occulter with various errors.…”

Section: Error Budgetmentioning

confidence: 99%

“…In particular, before building the petal we had modeled petal shape perturbations as ideal edge segment displacements and tilts combined with sine waves running the length of the petal, in addition to global size and shape errors. 4 After building the petal using high-precision Table 1. Worst-case allocated errors to each of the top 13 perturbations to meet the total allocated contrast due to random petal errors of 1.5 × 10 −11 .…”

Section: Error Budgetmentioning

confidence: 99%

See 1 more Smart Citation

Technology demonstration of starshade manufacturing for NASA's Exoplanet mission program

Kasdin

Lisman

Shaklan

et al. 2012

Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave

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It is likely that the coming decade will see the development of a large visible light telescope with enabling technology for imaging exosolar Earthlike planets in the habitable zone of nearby stars. One such technology utilizes an external occulter, a satellite flying far from the telescope and employing a large screen, or starshade, to suppress the incoming starlight sufficiently for detecting and characterizing exoplanets. This trades the added complexity of building the precisely shaped starshade and flying it in formation against simplifications in the telescope since extremely precise wavefront control is no longer necessary. In this paper we present the results of our project to design, manufacture, and measure a prototype occulter petal as part of NASA's first Technology Development for Exoplanet Missions program. We describe the mechanical design of the starshade and petal, the precision manufacturing tolerances, and the metrology approach. We demonstrate that the prototype petal meets the requirements and is consistent with a full-size occulter achieving better than 10 −10 contrast.

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Section: Error Budgetmentioning

confidence: 99%

Section: Error Budgetmentioning

confidence: 99%

Technology demonstration of starshade manufacturing for NASA's Exoplanet mission program

Kasdin

Lisman

Shaklan

et al. 2012

Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave

View full text Add to dashboard Cite

show abstract

“…Additionally, the operation of the occulter through varying thermal environments and dynamic loading will inevitably cause variations in the shape. Shaklan et al 11 describe in detail the modeling approach used to develop engineering requirements and determine the sensitivity of the design to errors in manufacture and variations in flight. An optical modeling tool has been developed, described there, that finds the image plane response of the telescope past an occulter with various errors.…”

Section: Requirements and Error Analysismentioning

confidence: 99%

Advancing technology for starlight suppression via an external occulter

et al. 2011

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External occulters provide the starlight suppression needed for detecting and characterizing exoplanets with a much simpler telescope and instrument than is required for the equivalent performing coronagraph. In this paper we describe progress on our Technology Development for Exoplanet Missions project to design, manufacture, and measure a prototype occulter petal. We focus on the key requirement of manufacturing a precision petal while controlling its shape within precise tolerances. The required tolerances are established by modeling the effect that various mechanical and thermal errors have on scatter in the telescope image plane and by suballocating the allowable contrast degradation between these error sources. We discuss the deployable starshade design, representative error budget, thermal analysis, and prototype manufacturing. We also present our metrology system and methodology for verifying that the petal shape meets the contrast requirement. Finally, we summarize the progress to date building the prototype petal.

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“…In a companion paper, we present an error budget for a 3.8 m telescope with a starshade. 12 Our coronagraph stability contrast error budget (CEB) is set up in an excel spreadsheet backed by layers of Visual Basic automation code and built on optical sensitivity matrices calculated from optical ray trace and diffraction codes. The error budget follows the overall approach outlined in Shaklan et al 2005 13 and utilizes updated versions of the automation features described in Marchen & Shaklan.…”

Section: Introductionmentioning

confidence: 99%

Stability error budget for an aggressive coronagraph on a 3.8 m telescope

Shaklan¹,

Marchen

Krist

et al. 2011

SPIE Proceedings

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We evaluate in detail the stability requirements for a band-limited coronagraph with an inner working angle as small as 2 λ/D coupled to an off-axis, 3.8-m diameter telescope. We have updated our methodologies since presenting a stability error budget for the Terrestrial Planet Finder Coronagraph mission that worked at 4 λ/D and employed an 8th-order mask to reduce aberration sensitivities. In the previous work, we determined the tolerances relative to the total light leaking through the coronagraph. Now, we separate the light into a radial component, which is readily separable from a planet signal, and an azimuthal component, which is easily confused with a planet signal. In the current study, throughput considerations require a 4th-order coronagraph. This, combined with the more aggressive working angle, places extraordinarily tight requirements on wavefront stability and opto-mechanical stability. We find that the requirements are driven mainly by coma that leaks around the coronagraph mask and mimics the localized signal of a planet, and pointing errors that scatter light into the background, decreasing SNR. We also show how the requirements would be relaxed if a low-order aberration detection system could be employed.

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A starshade petal error budget for exo-earth detection and characterization

Cited by 8 publications

References 5 publications

Technology demonstration of starshade manufacturing for NASA's Exoplanet mission program

Technology demonstration of starshade manufacturing for NASA's Exoplanet mission program

Advancing technology for starlight suppression via an external occulter

Stability error budget for an aggressive coronagraph on a 3.8 m telescope

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