The university of illinois at urbana-champaign (uiuc), in partnership with NASA goddard space flight center (gsfc) proposes a research program aimed at developing and demonstrating a new imaging…

This contract is a cooperative agreement awarded by the National Aeronautics and Space Administration (NASA) Shared Services Center to the University of Illinois at Urbana-Champaign (UIUC) in partnership with NASA's Goddard Space Flight Center (GSFC). The $400,000.00 award is for a research program aimed at developing and demonstrating a new imaging technology with unprecedented capabilities for scientific exploration.

The key focus is on advancing computational diffractive optical sensing, image processing, and small satellite formation flying to enable extremely high-resolution imaging in the extreme ultraviolet (EUV) wavelength range. This novel approach seeks to observe the thin current sheets in the solar corona that are theorized to play a key role in coronal heating, but are beyond the resolution of existing instruments. The UIUC team will develop optimal image deconvolution algorithms, while the GSFC team will build a laboratory simulator to validate the deconvolution process and demonstrate the milliarcsecond imaging capabilities. This contract does not have a set-aside designation.

The university of illinois at urbana-champaign (uiuc), in partnership with NASA goddard space flight center (gsfc) proposes a research program aimed at developing and demonstrating a new imaging technology with unprecedented capabilities for scientific exploration that will address this NRA's technology topic area 1: instrument technologies for small spacecraft. The technology innovation that will enable extremely high-resolution imaging capability, otherwise unattainable with conventional approaches, is based on a unique combination of novel computational diffractive optical sensing, advanced image processing, and small satellite formation flying. While the advent of such imaging technology has potential for broad impact in many areas of scientific exploration within NASA's science mission directorate, our initial targeted science area is within the domain of heliophysics and will address enabling technology for investigating coronal heating. Energy dissipation in the solar corona is believed to occur in extremely thin current sheets of order 1-100 KM. Emission from these hot but thin current sheets should be visible in coronal EUV emission lines. However, this spatial scale is far below the resolution of existing imaging instruments, so these dissipation sites have never been observed individually. Conventional optics cannot be manufactured with sufficient surface figure accuracy to obtain the required spatial resolution in the extreme-ultraviolet where these hot plasmas radiate. A photon sieve, a diffractive imaging element similar to a fresnel zone plate, can be manufactured to provide a few milli-arcsec (MAS) resolution, with much more readily achievable tolerances than with conventional imaging technology. Since the focal length of such diffractive lenses is wavelength-dependent, a full-scale ultra-high resolution instrument will require computational image deconvolution to disentangle superimposed contributions from multiple wavelengths along with formation flying (with the diffractive element and the detector on different small satellites with proper separation). Therefore, the proposed research for this NRA has two intertwined components that will be pursued concurrently and in close interaction between the uiuc and gsfc investigators. The uiuc team will develop optimal strategies for the formulation of the inherent inverse problem of photon sieve image deconvolution. Rigorous performance quantification necessitates the development of appropriate deconvolution algorithms that take full advantage of measurement diversity to produce the highest-attainable-resolution imagery via the development and application of numerical optimization algorithms. The gsfc personnel will develop a laboratory simulator to evaluate the performance of the deconvolution process. A multi-wavelength source simulating the EUV line emission from the solar corona will be developed. This source will be imaged by a 160 MM diameter photon sieve onto a CCD detector. Images will be taken at various axial focal positions, and the data from this simulation will be used to validate the deconvolution, and to quantify and demonstrate the MAS imaging system's performance in a realistic experimental setting. The advent of such novel imaging capability will not only enable the investigation of the structure of the corona at a resolution never before obtained, IT will also allow a study of the temperature structure in the dissipation region at these resolutions.