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

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

Research output: Chapter in Book/Report/Conference proceedingConference contribution

13 Scopus citations


We present a starshade error budget with engineering requirements that are well within the current manufacturing and metrology capabilities. The error budget is based on an observational scenario in which the starshade spins about its axis on timescales short relative to the zodi-limited integration time, typically several hours. The scatter from localized petal errors is smoothed into annuli around the center of the image plane, resulting in a large reduction in the background flux variation while reducing thermal gradients caused by structural shadowing. Having identified the performance sensitivity to petal shape errors with spatial periods of 3-4 cycles/petal as the most challenging aspect of the design, we have adopted and modeled a manufacturing approach that mitigates these perturbations with 1-m long precision edge segments positioned using commercial metrology that readily meets assembly requirements. We have performed detailed thermal modeling and show that the expected thermal deformations are well within the requirements as well. We compare the requirements for four cases: a 32 m diameter starshade with a 1.5 m telescope, analyzed at 75 and 90 mas, and a 40 m diameter starshade with a 4 m telescope, analyzed at 60 and 75 mas.

Original languageEnglish (US)
Title of host publicationTechniques and Instrumentation for Detection of Exoplanets V
StatePublished - 2011
EventTechniques and Instrumentation for Detection of Exoplanets V - San Diego, CA, United States
Duration: Aug 23 2011Aug 24 2011

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherTechniques and Instrumentation for Detection of Exoplanets V
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Applied Mathematics
  • Electrical and Electronic Engineering
  • Computer Science Applications


  • Coronagraphy
  • error budget
  • external occulters
  • high contrast imaging
  • starshades


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