About

Ewan S. Douglas is an Associate Professor of Aerospace and Mechanical Engineering at the University of Arizona. His role involves teaching and research within the department, contributing to the academic community through his expertise in aerospace and mechanical engineering. The page indicates his association with the university's faculty and staff, emphasizing his position and contact information, but does not provide specific details about his research focus, background, or key contributions.

Research topics

• Computer Science
• Physics
• Remote sensing
• Optics
• Astronomy
• Astrobiology
• Geology
• Artificial Intelligence
• Algorithm
• Engineering
• Geography
• Aerospace engineering
• Computer vision
• Operating system

Selected publications

• Low Thrust Electric Propulsion Mission Concepts for a 3 Meter-Class Space Telescope

  2026-05-13

  articleSenior author

  Space-based telescopes benefit from operating in stable orbital environments with reduced exposure to radiation and thermal fluctuations in order to minimize cost and maximize time for high-quality observations. Finding this ideal environment proves beneficial particularly for exoplanet discovery and characterization; direct imaging requires sub-nanometer wavefront stability and multi-hour observations, and transit detection requires parts-per-million photometric accuracy. Our team at University of Arizona's Steward Observatory and the Wyant College of Optical Sciences is evaluating various mission concepts for a 3-meter class telescope design, flying on a spacecraft bus equipped with a low thrust propulsion system. The presented mission analysis focuses on obtaining suitable transfer trajectories to the desired science orbit as well as understanding the radiation environment during the transfer, which is relevant for low thrust missions. The science analysis explores different operating orbits with the purpose of yielding maximum scientific return for detecting exoplanets. In this paper, we evaluate the use of a 2:1 lunar resonant orbit and a Sun-Earth L2 halo orbit for our mission.

  PublisherDOI

• The Lazuli Space Observatory: Architecture & Capabilities

  arXiv (Cornell University) · 2026-01-05

  preprintOpen access

  The Lazuli Space Observatory is a 3-meter aperture astronomical facility designed for rapid-response observations and precision astrophysics across visible to near-infrared wavelengths (400-1700 nm bandpass). An off-axis, freeform telescope delivers diffraction-limited image quality (Strehl $>$0.8 at 633 nm) to three instruments across a wide, flat focal plane. The three instruments provide complementary capabilities: a Wide-field Context Camera (WCC) delivers multi-band imaging over a 35' $\times$ 12' footprint with high-cadence photometry; an Integral Field Spectrograph (IFS) provides continuous 400-1700 nm spectroscopy at R $\sim$ 100-500 for stable spectrophotometry; and an ExtraSolar Coronagraph (ESC) enables high-contrast imaging expected to reach raw contrasts of $10^{-8}$ and post-processed contrasts approaching $10^{-9}$. Operating from a 3:1 lunar-resonant orbit, Lazuli will respond to targets of opportunity in under four hours--a programmatic requirement designed to enable routine temporal responsiveness that is unprecedented for a space telescope of this size. Lazuli's technical capabilities are shaped around three broad science areas: (1) time-domain and multi-messenger astronomy, (2) stars and planets, and (3) cosmology. These capabilities enable a potent mix of science spanning gravitational wave counterpart characterization, fast-evolving transients, Type Ia supernova cosmology, high-contrast exoplanet imaging, and spectroscopy of exoplanet atmospheres. While these areas guide the observatory design, Lazuli is conceived as a general-purpose facility capable of supporting a wide range of astrophysical investigations, with open time for the global community. We describe the observatory architecture and capabilities in the preliminary design phase, with science operations anticipated following a rapid development cycle from concept to launch.

  PublisherDOI

• spacehardwarehandbook-public

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-04

  otherOpen access1st authorCorresponding

  UASAL Space Hardware Handbook- Living collection of documents / guides for low-cost space instrumentations builders.

  PublisherDOI

• The Lazuli Space Observatory: Architecture & Capabilities

  ArXiv.org · 2026-01-05

  articleOpen access

  International audience

  PublisherOA PDF

• Stages of commissioning alignment for three-mirror anastigmat (TMA) telescopes

  2025-09-17

  article

  Reliable, autonomously, deployment of telescopes enables a wide range of possible science cases. In this paper, we present a method for multi-stage telescope alignment with a simple commercial imaging sensor. For these studies, we use a design of an example three mirror anastigmat (TMA) telescope and consider how the average spot size across the detector changes as a function of primary (M1) and secondary (M2) mirror positioning. This multi-stage alignment procedure will consist of three subprocesses, starting with a coarse alignment and converging down to a finer alignment before moving on to a stage where the telescope will refine its misalignments for data acquisition. This alignment strategy has been tested and meets “diffraction limited” requirements on a subset of misalignment cases from a statistical Monte-Carlo simulation given misalignment tolerances on the telescope.

  PublisherDOI

• Preliminary characterization results for Sony IMX CMOS imaging sensors for astronomical imaging

  2025-09-17

  article

  CMOS imaging sensors have undergone remarkable technological advancements in the last decade. The performance of industrial grade CMOS imagers, especially with the introduction of back-side illumination, has progressed to the point where even these OTS sensors are now being considered as low-cost but high-performance alternates to the more expensive traditional CCDs used in astronomy applications. Stewart Observatory is prototyping instruments using multiple instances of several Sony IMX industrial grade sensors. We have designed a characterization program to test approximately 40 IMX sensors of three different models. The program includes standard characterization tests (defects, read noise, dark current, PRNU, QE, FWC and linearity), as well as tests aimed at understanding parameter variability between instances of the same sensor (conversion gain mapping, QE yield, image lag, RTS noise, & MTF). We begin by reviewing relevant material on CMOS imaging sensors, and then identify the parameters that the characterization program will measure. We describe the characterization tests and sequence, present preliminary results, and discuss the implications for astronomical imaging.

  PublisherDOI

• The Space Coronagraph Optical Bench (SCoOB): 8. end-to-end numerical modeling of the testbed to estimate the contrast limits

  2025-09-18

  articleSenior author

  The space coronagraph optical bench (SCoOB) at the University of Arizona is a high-contrast imaging testbed designed to operate in a vacuum to obtain a contrast better than 10−8 in optical wavelengths using vector vortex coronagraph (VVC) masks. The testbed performance in a half-sided D-shaped dark hole is 2.2×10⁻⁹ in a ≪ 1% BW, 4 × 10⁻⁹ in a 2% BW, and 2.5 × 10⁻⁸ in a 15% BW. While the testbed has met the design specification contrast requirements in monochromatic wavelengths, comprehensive end-to-end numerical modeling to assess contrast limits across different bandpasses has yet to be conducted. In this work, we discuss the results of numerical modeling for the SCoOB testbed in both monochromatic and 10% bandwidths at 525nm and 630nm. This modeling incorporates measured VVC retardance, modeled polarization aberrations, measured surface and reflectivity errors, and diffuse and surface reflectivity. We explore and discuss the various factors contributing to the contrast limits.

  PublisherDOI

• On-orbit commissioning phase three mirror anastigmat telescope alignment using blind scanning search

  2025-09-17

  article

  Astronomical telescopes are subject to multiple environmental factors resulting in the misalignment of optics, affecting their ability to efficiently collect starlight flux or resolve targets. Severe translational misalignments, such as the primary (M1) mirror relative positioning, can degrade image quality and may be insufficient to correct using typical alignment techniques in the initial phase of commissioning. However, allowing for large initial misalignment errors can relax optomechanical requirements and potentially reduce fabrication and integration costs. To address these challenges, a novel star-field blind scanning alignment technique is proposed to achieve first-order commissioning and compensate for initial misalignment without requiring additional calibration hardware. In systems with severe misalignment, star images on the detector plane may be comparable to or even larger than the detector size. The proposed Blind Scanning algorithm, simulated using a three-mirror anastigmat (TMA) telescope, is an autonomous and coarse alignment method that acquires total photon flux on the detector plane while the M1 optics move according to a scheduled motion in x, y, and z that span severe misalignment ranges. Fluxtrend statistics guide the first-order alignment and facilitate the transition to the finer alignment commissioning phase without the need for initial wavefront sensing. We first demonstrated this method using a simplified PSF model to assess detector response under various misalignment scenarios. Next, we implemented automated misalignment sweeps via ZOS-API in a non-sequential Zemax model, measuring flux on both a narrow-field single chip detector and full-field wide chip detector representing the telescope detector array. By plotting photon counts across twelve misalignment cases, we construct a 3D flux landscape that reduces large translation errors from about 20 mm down to roughly 5 mm on a three-meter-class primary mirror. Finally, stochastic parallel gradient descent (SPGD) and phase-retrieval techniques fine-tune the point spread function to achieve diffraction-limited performance. This strategy effectively counters severe misalignments before applying higher-precision alignment methods, offering a cost-effective solution for dynamic environments.

  PublisherDOI

• Black silicon characterization for coronagraphs

  2025-09-18

  article

  The Habitable Worlds Observatory (HWO) flagship mission plans to image and spectrally characterize earth-like exoplanets at 10⁻¹⁰ planet-to-star contrast with a coronagraph instrument. HWO’s 6-meter primary mirror will mostly likely be segmented for launch-related mass and packaging constraints. To suppress the extra diffraction from the primary mirror segmentation, a pupil apodizer mask could be used as part of several coronagraphic architectures. Reflective amplitude apodizers using cryogenic black silicon have already been flight qualified to 4 × 10⁻⁹ contrast for the Roman Space Telescope. In this paper, we detail our laboratory experiments and numerical simulations to characterize the amount of stray light from black silicon at levels relevant to HWO’s contrast budget.

  PublisherDOI

• Wave simulation for diffraction efficiency of an integral field spectrograph

  2025-09-17

  article
  PublisherDOI

Frequent coauthors

• Kerri Cahoy

  American Institute of Aeronautics and Astronautics

  86 shared

• Olivier Guyon

  National Astronomical Observatory of Japan

  45 shared

• Daewook Kim

  44 shared

• Jaren N. Ashcraft

  41 shared

• M. Granata

  Université Claude Bernard Lyon 1

  40 shared

• E. Chassande–Mottin

  Laboratoire AstroParticule et Cosmologie

  40 shared

• Kyle Van Gorkom

  39 shared

• S. Chakrabarti

  University of Massachusetts Lowell

  38 shared

Education

• PhD, Astronomy

  Boston University

  2016