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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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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

Metrology-based Techniques for Optical System Alignment for the OSIRIS-Rx Visual and InfraRed Spectrometer

The alignment, integration, and test group (AI&T) in the optics branch at NASA Goddard Space Flight Center (GSFC) specializes in optical and opto-mechanical alignment and metrology for project ranging from building and testing instrument such as spectrometers and cameras to larger structures such as telescopes to large volume metrology and alignment at the observatory level for spacecraft payloads. One of the projects that involved the support of the AI&T group was the OSIRIS-Rex Visual and Infra-Red Spectrometer (OVIRS) for the Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer (OSIRIS-Rex) mission. The purpose of this report is to outline the tools, methods, and approaches to metrology utilized by the AI&T group and how they were applied specifically to the optical alignment of the elements on OVIRS during the ambient I&T phase.

Young, Jerrod↗
NASA NTRS1991

Post-flight characterization of optical system samples, thermal control samples, and detectors from LDEF experiment M0003, sub-experiments 6 and 13

Flight samples and control samples of optical and thermal control coatings were measured for hemispheric reflectance and transmission. The samples were exposed directly to the orbital environment, but were on the trailing edge of the LDEF satellite. Preliminary analysis shows no significant change in the reflectance of transmission values of most of the samples. Post-flight tests of avalanche photodiodes is also discussed.

Hodgson, Randall R.↗
NASA NTRS1992

Post-flight characterization of optical system samples, thermal control samples, and detectors from LDEF experiment M0003, sub-experiments 6 and 13

Flight samples and control samples of optical and thermal control coatings have been measured for hemispheric reflectance and transmission. Data was recorded for wavelengths from .25 microns to 18 microns. The samples were exposed directly to the orbital environment, but were on the trailing edge of the LDEF satellite. Preliminary analysis shows no significant change in the reflectance or transmission values of most of the samples. Post-flight tests of avalanche photodiodes have yielded results. The tests consist of measuring the following detector parameters: breakdown voltage for set values of reverse current, responsivity vs. bias voltage, noise equivalent power, and uniformity of photoresponse. The avalanche photodiodes were mounted on the leading edge of the LDEF satellite, but were shielded from the outside by a silver-coated teflon foil cover. Small puncture holes are present in the foil, probably caused by impact of particles in orbit. For most of the detectors, there has been no significant change in noise or response.

Randall R Hodgson↗
NASA NTRS2019

An Improved Far-Field Small Unmanned Aerial System Optical Detection Algorithm

Onboard far-field aircraft detection is needed for safe non-cooperative traffic mitigation for autonomous small Unmanned Aerial System (sUAS) operations. This work presents an aircraft detect and track pipeline that fuses image differencing and morphological filtering detections for inputs to a Kalman-based object tracking pipeline. The pipeline is evaluated using two types of flight encounters: 1) motorcopter sUAS vs. fixed-wing sUAS 2) motorcopter sUAS vs general aviation plane.

Chester Dolph↗
NASA NTRS1991

Preliminary analysis of WL experiment number 701: Space environment effects on operating fiber optic systems

A brief overview of the analysis performed on WL Experiment number 701 is presented, highlighting the successful operation of the first know active fiber optic links orbited in space. Four operating fiber optic links were exposed to the space environment for a period exceeding five years, situated aboard and external to the Long Duration Exposure Facility (LDEF). Despite the prolonged space exposure to radiation, wide temperature extremums, atomic oxygen interactions, and micrometeorite and debris impacts, the optical data links performed well within specification limits. Early Phillips Laboratory tests and analyses performed on the experiment and its recovered magnetic tape data strongly indicate that fiber optic application in space will have a high success rate.

Taylor, E. W.↗
NASA NTRS1973

Pioneer imaging photopolarimeter optical system.

The imaging photopolarimeter aboard the Pioneer 10 spacecraft en route to the vicinity of Jupiter is described. This instrument is capable of moderate resolution spin-scan imaging and high precision polarimetric and photometric mapping of Jupiter in red and blue light. The field of view can be selectively changed from 0.50 mrad square to 40 mrad square to accommodate resolution and radiance combinations ranging from the zodiacal background to that of Jupiter. Optical materials were chosen to survive, with minimum degradation, the rigors of a nearly 2-year journey to Jupiter including transit through the Jovian trapped radiation belts. The optics are described in detail, and the operational system is outlined. The procedures for preflight and in-flight calibration are described, and some performance characteristics and preliminary flight results are presented.

Pellicori, S. F.↗
NASA NTRS2018

HabEx Space Telescope Optical System Overview: General Astrophysics Instruments

The HabEx (Habitable Exoplanet) concept study is defining a future space telescope with the primary mission of detecting and characterizing planetary systems around nearby stars. The telescope baseline design includes a high-contrast coronagraph and a starshade to enable the direct optical detection of exoplanets as close as 70 mas to their star. In addition to the study of exoplanets, HabEx carries two dedicated instruments for general astrophysics. The first instrument is a camera enabling imaging on a 3 arc minute field of view in two bands stretching from the UV at 150 nm to the near infrared at 1800 nm. The same instrument can also be operated as a multi-object spectrograph, with resolution of 2000. The second instrument is a high-resolution UV spectrograph operating from 300 nm down to 115 nm with up to 60,0000 resolution. HabEx would provide the highest resolution UV/optical images ever obtained. Diffraction limited at 0.4 µm, it would outperform all current and approved facilities, including the 30 m class ground-based extremely large telescopes (ELTs), which will achieve ~0.01 arcsecond resolution at near-infrared (IR) wavelengths with adaptive optics, but will be seeing-limited at optical wavelengths. HabEx would observe wavelengths inaccessible from the ground, including the UV and in optical/near-IR atmospheric absorption bands. Operating at L2, far above the Earth’s atmosphere and free from the large thermal swings inherent to HST’s low-Earth orbit, HabEx would provide an ultra-stable platform that will enable science ranging from precision astrometry to the most sensitive weak lensing maps ever obtained. Here we discuss the design concepts of the general astrophysics optical instruments for the proposed observatory.

Nissen, Joel↗
NASA NTRS1990

Wavefront control of large optical systems

Several levels of wavefront control are necessary for the optimum performance of very large telescopes, especially segmented ones like the Large Deployable Reflector. In general, the major contributors to wavefront error are the segments of the large primary mirror. Wavefront control at the largest optical surface may not be the optimum choice because of the mass and inaccessibility of the elements of this surface that require upgrading. The concept of two-stage optics was developed to permit a poor wavefront from the large optics to be upgraded by means of a wavefront corrector at a small exit pupil of the system.

Meinel, Aden B.↗
NASA NTRS1989

Cryogenic optical systems and instruments III; Proceedings of the Meeting, San Diego, CA, Aug. 17-19, 1988

Topics considered include the Space Infrared Telescope Facility (SIRTF) and superfluid helium on-orbit transfer (SHOOT), SIRTF cryogenic optics technology, and Cosmic Background Explorer scientific instruments, and the Advanced X-ray Astrophysics Facility (AXAF) cryogenic subsystem. Attention is also given to the Stratospheric Observatory for Infrared Astronomy (SOFIA), high-volume IR array testing and detector coolers, the development of IR detectors and associated electronics, and the Cryogenic Limb Array Etalon Spectrometer (CLAES).

Melugin, Ramsey K.↗
DOE OSTI2021

Fiber optic system for direct detection of CO 2 leakage in carbon storage wells (Abbreviated Final Report)

The feasibility study focused on the development of new fiber for distributed chemical sensing that will allow direct detection of CO2 leakages in the environment. This is particularly important for monitoring well integrity for carbon capture and storage (CSS), which can provide early warning for an incoming well failure and potential CO2 leaking through it. We proposed Raman or IR interrogation within gas-filled Holey Fibers (HoFs) interleaved with Fiber Bragg Grating (FBG) sections, so that the location and concentration of the gases would be provided simultaneously. The methodology would overcome current roadblocks to using fiber optics for CO2 (and other gases) detection in wells with direct in-situ measurements of concentration along with other important parameters such as temperature and pressure. We were able to assess commercially available IR/Raman hollow core fiber and demonstrated detection of CO2 through them in our controlled environment setups at various pressure conditions. We have also established the ability of drilling precisely with fs-lases side holes to enable penetration of CO2 into the hollow core fiber and reduce diffusion rates. Open joint collars were also explored with double functionality: to obtain splice to solid core fiber critical for field deployment and create gas ingress locations. Both diffusion-only and pressurized fiber system have been constructed following COMSOL based semi-hybrid optical /fluidodynamics models. FBGs have been identified and procured and characterized. Along the work we leveraged internal modeling/design, photonics/laser characterization, optical fiber fabrication, and AM lab capabilities to design, develop and test in-house components or assemblies. Our results indicate the potential of HoF for CO2 downhole direct detection.

25 ENERGY STORAGE↗
NASA NTRS1982

Throughput of diffraction-limited field optics systems for infrared and millimetric telescopes

Telescopes for submillimeter wavelengths have point spread functions some millimeters or centimeters in diameter, but the detectors may be only fractions of a millimeter in size. Thus a field aperture and collecting optics are needed. Optimizing the aperture by a calculation of the effects of diffraction on signal and resolution as a function of size of the collecting aperture is shown. Calculations are compared to experimental results from observations of Mars at submillimeter wavelengths.

Hildebrand, R. H.↗
NASA NTRS1985

Challenges of developing an electro-optical system for measuring man's operational envelope

In designing work stations and restraint systems, and in planning tasks to be performed in space, a knowledge of the capabilities of the operator is essential. Answers to such questions as whether a specific control or work surface can be reached from a given restraint and how much force can be applied are of particular interest. A computer-aided design system has been developed for designing and evaluating work stations, etc., and the Anthropometric Measurement Laboratory (AML) has been charged with obtaining the data to be used in design and modeling. Traditional methods of measuring reach and force are very labor intensive and require bulky equipment. The AML has developed a series of electro-optical devices for collecting reach data easily, in computer readable form, with portable systems. The systems developed, their use, and data collected with them are described.

Woolford, B.↗
NASA NTRS1993

Integrated modeling of advanced optical systems

This poster session paper describes an integrated modeling and analysis capability being developed at JPL under funding provided by the JPL Director's Discretionary Fund and the JPL Control/Structure Interaction Program (CSI). The posters briefly summarize the program capabilities and illustrate them with an example problem. The computer programs developed under this effort will provide an unprecedented capability for integrated modeling and design of high performance optical spacecraft. The engineering disciplines supported include structural dynamics, controls, optics and thermodynamics. Such tools are needed in order to evaluate the end-to-end system performance of spacecraft such as OSI, POINTS, and SMMM. This paper illustrates the proof-of-concept tools that have been developed to establish the technology requirements and demonstrate the new features of integrated modeling and design. The current program also includes implementation of a prototype tool based upon the CAESY environment being developed under the NASA Guidance and Control Research and Technology Computational Controls Program. This prototype will be available late in FY-92. The development plan proposes a major software production effort to fabricate, deliver, support and maintain a national-class tool from FY-93 through FY-95.

Briggs, Hugh C.↗
NASA NTRS1972

A computer program to evaluate optical systems

A computer program is used to evaluate a 25.4 cm X-ray telescope at a field angle of 20 minutes of arc by geometrical analysis. The object is regarded as a point source of electromagnetic radiation, and the optical surfaces are treated as boundary conditions in the solution of the electromagnetic wave propagation equation. The electric field distribution is then determined in the region of the image and the intensity distribution inferred. A comparison of wave analysis results and photographs taken through the telescope shows excellent agreement.

Innes, D.↗