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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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30 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Image analysis of the AXAF VETA-1 X-ray mirror

Initial core scan data of the VETA-1 X-ray mirror proved disappointing, showing considerable unpredicted image structure and poor measured FWHM. 2-D core scans were performed, providing important insight into the nature of the distortion. Image deconvolutions using a raytraced model PSF was performed successfully to reinforce our conclusion regarding the origin of the astigmatism. A mechanical correction was made to the optical structure, and the minor was tested successfully (FWHM 0.22 arcsec) as a result.

Freeman, M.↗
NASA NTRS1993

Surface finish quality of the outer AXAF mirror pair based on X-ray measurements of the VETA-I

We employ the X-ray measurements of the VETA-I taken at the X-Ray Calibration Facility (XRCF) of the Marshall Space Flight Center (MSFC) to extract information about the surface finish quality of the outermost pair of AXAF mirrors. The particular measurements we consider are 1D scans of the core of the point response function (PRF) (FWHM scans), the encircled energy as a function of radius, and 1D scans of the wings of the PRF. We discuss briefly our raytrace model which incorporates the numerous effects present in the VETA-I test, such as the finite source distance, the size and shape of the X-ray source, the residual gravitational distortions of the optic, the despace of the VETA-I, and particulate contamination. We show how the data constrain the amplitude of mirror surface deviations for spatial frequencies greater than about 0.1/mm. Constraints on the average amplitude of circumferential slope errors are derived as well.

Hughes, John P.↗
NASA NTRS2000

Deconvolving the Nucleus of Centaurus A Using Chandra PSF Library

Centaurus A (NGC 5128) is a giant early-type galaxy containing the nearest (at 3.5 Mpc) radio-bright Active Galactic Nucleus (AGN). Cen A was observed with the High Resolution Camera (HRC) on the Chandra X-ray Observatory on several occasions since the launch in July 1999. The high-angular resolution (less than 0.5 arcsecond) Chandra/HRC images reveal X ray multi-scale structures in this object with unprecedented detail and clarity, including the bright nucleus believed to be associated with a supermassive black hole. We explored the spatial extent of the Cen A nucleus using deconvolution techniques on the full resolution Chandra images. Model point spread functions (PSFs) were derived from the standard Chandra raytrace PSF library as well as unresolved point sources observed with Chandra. The deconvolved images show that the Cen A nucleus is resolved and asymmetric. We discuss several possible causes of this extended emission and of the asymmetries.

Karovska, Margarita↗
NASA NTRS2019

Serendipitous Geodesy from Bennu's Short-Lived Moonlets

The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx; or OREx) spacecraft arrived at its target, near-Earth asteroid (101955) Bennu, on December 3, 2018. The OSIRIS-REx spacecraft has since collected a wealth of scientific information in order to select a suitable site for sampling. Shortly after insertion into orbit on December 31, 2018, particles were identified in starfield images taken by the navigation camera (NavCam 1). Several groups within the OSlRlS-REx team analyzed the particle data in an effort to better understand this newfound activity of Bennu and to investigate the potential sensitivity of the particles to Bennu's geophysical parameters. A number of particles were identified through automatic and manual methods in multiple images, which could be turned into short sequences of optical tracking observations. Here, we discuss the precision orbit determination (OD) effort focused on these particles at NASA GSFC, which involved members of the Independent Navigation Team (INT) in particular. The particle data are combined with other OSIRIS-REx tracking data (radiometric from OSN and optical landmark data) using the NASA GSFC GEODYN orbit determination and geodetic parameter estimation software. We present the results of our study, particularly those pertaining to the gravity field of Bennu. We describe the force modeling improvements made to GEODYN specifically for this work, e.g., with a raytracing-based modeling of solar radiation pressure. The short-lived, low-flying moonlets enable us to determine a gravity field model up to a relatively high degree and order: at least degree 6 without constraints, and up to degree 10 when applying Kaula-like regularization. We can backward- and forward-integrate the trajectory of these particles to the ejection and landing sites on Bennu. We assess the recovered field by its impact on the OSIRIS-REx trajectory reconstruction and prediction quality in the various mission phases (e.g., Orbital A, Detailed Survey, and Orbital B).

Mazarico, Erwan↗
NASA NTRSDate not supplied

Curved Diffractive X-ray Optics for X-ray Astronomy

We report on a concept for curved diffractive X-ray optics (CDXO). CDXO would enable potential new optical designs for X-ray instruments, such as a two element spectrometer, in which the secondary element of an X-ray mirror pair is patterned with an X-ray grating. A two-element spectrometer design eliminates the grating assembly, resulting in decreased instrument mass and reduced power requirements. In addition, a two-element spectrometer may realize cost/schedule savings by eliminating a separate grating alignment effort, and yield increased effective area over three element designs. We present a raytrace concept study of a two-element spectrometer compact enough to fit within a sounding rocket payload. We also review the progress made in electron-beam lithography (EBL) techniques that would enable curved diffractive X-ray optics to be patterned, and outline a procedure by which the accuracy of the EBL patterning process can be measured interferometrically.

Casey T. DeRoo↗
NASA NTRSDate not supplied

Artemis 1 Radiation Modeling and Analysis Using Operational Methods

The successful completion of the Artemis 1 mission has provided NASA with a significant volume of space radiation dosimetry data that can be used to verify the accuracy of current operational SRAG dose computation models and methods for Beyond LEO missions. High-Fidelity CAD models of the Artemis 1 MPCV Orion were raytraced in 10,000 directions per sensor location, including the location of Artemis HERA sensors, Artemis RAMs (TLDs), and the crew active dosimetry (CADs). The full Artemis 1 mission was modelled using the as-flown trajectory, Ap9-Ae9 IRENE providing the VAB trapped proton and electron environment, and the Badhwar-O’Neill 2020 model providing the freespace GCR environment. IGRF 12 was used to compute cutoff rigidities for the GCR environment in LEO. 1DHZETRN was used to estimate point doses at each sensor position. Computed RAM doses were within 5% of measured values. The computed VAB transit and freespace GCR dose rates showed good qualitative agreement with measured HERA values. An estimate of normalized mean effective dose for a hypothetical male crew member on Artemis 1 using current standard operational methods was computed to be 22.3 mSv.

Artemis 1↗
NASA NTRSDate not supplied

Design and Analysis of the Rocket Experiment Demonstration of a Soft X-Ray (REDSoX) Polarimeter Mirror Module Assembly

The Rocket Experiment Demonstration of a Soft X-ray (REDSoX) Polarimeter is a NASA sounding rocket experiment that is designed to demonstrate the technology necessary for measuring linear X-ray polarization as a function of energy below 1 keV. In astrophysics, soft X-ray spectropolarimetry will be used to probe the nature of acceleration mechanisms in quasar jets and to test models of neutron star structure. NASA Marshall Space Flight Center (MSFC) has designed a grazing-incidence mirror module assembly (MMA) for the REDSoX payload and used Finite Element Modelling Software (ANSYS) to perform structural analysis of the design. In this paper we will describe the overall design of the REDSoX MMA, details of the analysis techniques used for predicting factor of safety in the mirror adhesive bonds and structural components, the buckling analysis of the outer housing, and the raytrace technique used to estimate the effect of gravity sag on optical performance during ground testing.

Structural Analysis↗
DOE OSTI2024

NREL's Tools for AgriPV Modeling

As part of the Tools and Apps for Agrivoltaics session, NREL presents their tools that have capabilities for modeling PV and agricultural dual use sites. These include the System Advisor Model (SAM), bifacial_radiance open-source raytracing tool, and a simplified agriPV calculator available in the InSPIRE website.

agriculture↗
DOE OSTI2024

Illuminating Agrivoltaics at NREL

In this talk, we will provide an overview of the INSPIREing work being done in the agrivoltaics field at NREL. We will focus on the modeling aspects of agrivoltaics, discussing key assumptions and metrics that guide research, and main open concerns from the community. We will innovative solutions implement at NREL for modeling, and ongoing experiments for shading and irradiance modeling. We will conclude with a look at the future steps necessary to advance this particular area of agrivoltaics.

14 SOLAR ENERGY↗
DOE OSTI2026

Agrivoltaics: Unlocking the Potential of Dual Land Use

This tutorial will delve into the practical and technical considerations for agrivoltaic systems, including crop selection, agricultural practices, and solar energy optimization. Leveraging insights from successful case studies, we'll address challenges such as policy barriers and regulatory gaps while exploring opportunities and incentives for implementation. With a focus on PV expertise, attendees will gain actionable knowledge on designing and evaluating dual-use systems that balance energy generation with agricultural productivity.

14 SOLAR ENERGY↗