Abstract

The Near-Earth Object (NEO) Surveyor is a planned NASA planetary defense mission designed to identify 66% of the potentially hazardous earth-crossing NEOs within its five-year baseline mission. To accomplish this goal, NEO Surveyor will use two wavelength channels. Each channel will be comprised of four HgCdTe HAWAII-2RG (H2RG) detector arrays. The first channel, known as NC1, will use midwave infrared (MWIR) 6 μm cutoff arrays to cover the 4–5.2 μm range and the second channel, NC2, will use longwave infrared (LWIR) 10.5 μm cutoff wavelength arrays to cover the 6–10 μm range. Although some data are presented for the MWIR arrays, the dominant focus is on the LWIR arrays that are the result of a lengthy development partnership among the University of Rochester, Teledyne Imaging Systems, the University of Arizona, the Jet Propulsion Laboratory, and the Space Dynamics Laboratory.

These newly developed LWIR arrays will be operated in space for the first time on NEO Surveyor and as a result require extra effort to focus on routine calibration methods and mitigation of undesirable detector behaviors to ensure the detectors can produce images with the quality required for NEO Surveyor to accomplish its planetary defense objectives. Presented here are detailed investigations into these categories to ensure the LWIR arrays will be sufficient for NEO Surveyor’s goals.

First, experimental proof of the need for a non-unity scale factor when performing direct reference pixel correction because of a capacitive mismatch between active pixels and reference pixels is presented. To strengthen the routine data reduction process, the impacts of several different reference pixel correction methods are also investigated. Next, work behind the discovery of an additional brighter-fatter effect is presented. This effect is characterized by saturated pixels spilling over and sharing current with their neighbors. Finally, a measurement of the modulation transfer function (MTF) is performed using a monotonic slanted edge to estimate the current image quality and how it scales with wavelength and signal. The resulting MTF measurements suggest that with proper calibration and removal of small detector effects, the LWIR arrays will provide an image quality suitable for NEO Surveyor.

Details

Title
Mitigating Undesirable Detector Behaviors for Improved Image Quality from the Near-Earth Object Surveyor
Author
Zengilowski, Gregory Ryan  VIAFID ORCID Logo 
Publication year
2021
Publisher
ProQuest Dissertations & Theses
ISBN
9798762103817
Source type
Dissertation or Thesis
Language of publication
English
ProQuest document ID
2618860783
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.