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NASA NTRS2017

PE-46 The Design of the Lynx X-Ray Microcalorimeter

Lynx is an x-ray telescope, one of four large satellite mission concepts currently being studied by NASA to be the next astrophysics flagship mission after WFIRST. One of Lynx's three instruments is an imaging spectrometer consisting of an x-ray microcalorimeter behind an X-ray optic with an angular resolution of 0.5 arc-seconds and approximately 3 sq m of area at 1 keV. This instrument will provide unparalleled diagnostics of distant extended structures and in particular will allow the detailed study of the role of cosmic feedback in the evolution of the Universe. We discuss the design and read-out of the of the array configuration including a number of sub-array options for increasing the capabilities to maximize the scientific return of the Lynx observatory.

Bandler, Simon↗

NASA NTRS2017

A Celestial Reference Frame Based on Kalman Filtering

In this study, we investigate a novel approach to the determination of celestial reference frames (CRF). Instead of a constant model for radio sources positions, we adopt a time series representation, which allows temporal variations of radio source coordinates to be taken into account. In particular, the added flexibility is beneficial for radio sources with extended structure. We compute our time series-based CRF solutions by Kalman filtering and smoothing radio source positions, which are initially obtained from single-session VLBI analysis. The temporal resolution of the estimated CRF coordinates is identical to that of the input data, i.e. usually 1-4 days. The magnitude of the coordinate variations is controlled by the amount of process noise applied in the filter, which is in turn derived from analyzing the Allan standard deviation of the corresponding radio source coordinate time series. Measures have been developed to reduce the impact of observation errors and datum effects on the noise model.

Soja, B.↗

NASA NTRS2019

AWARE: An Algorithm for the Automated Characterization of EUV Waves in the Solar Atmosphere

Conference Poster-Introduction Extreme ultraviolet (EUV) waves are large-scale propagating disturbances observed in the solar corona, frequently associated with coronal mass ejections and flares (Thompson et al., 1999, Thompson & Myers 2009). They appear as faint, extended structures propagating from a source region across the structured solar corona, making them difficult to isolate and measure. To further the understanding of EUV waves, we have constructed the Automated Wave Analysis and REduction (AWARE) algorithm for the measurement of EUV waves (Ireland et al, submitted). AWARE is implemented using the persistence transform, simple image processing operations and the RANSAC algorithm.

Ireland, Jack↗

NASA NTRS2019

AWARE: an Algorithm for the Automated Characterization of EUV Waves in the Solar Atmosphere

Extreme ultraviolet (EUV) waves are large-scale propagating disturbances observed in the solar corona, frequently associated with coronal mass ejections and flares. They appear as faint, extended structures propagating from a source region across the structured solar corona. To measure these waves, we have constructed the Automated Wave Analysis and REduction (AWARE) algorithm. AWARE is implemented in two stages. In the first stage, we use simple image processing techniques to isolate the propagating, brightening wave fronts as they move across the corona. In the second stage, AWARE measures the distance, velocity and acceleration of that wave front across the Sun. We explore the use of the Huygens principle, dynamic time warping and a simple parametric representation of the wave front as potential methods for detecting and tracking non-radial EUV wave propagation.

Ireland, Jack↗

NASA NTRS2019

Lynx x-ray microcalorimeter

Lynx is an x-ray telescope, one of four large satellite mission concepts currently being studied by NASA to be a flagship mission. One of Lynx’s three instruments is an imaging spectrometer called the Lynx x-ray microcalorimeter (LXM), an x-ray microcalorimeter behind an x-ray optic with an angular resolution of 0.5 arc sec and ∼2 sq. m of area at 1 keV. The LXM will provide unparalleled diagnostics of distant extended structures and, in particular, will allow the detailed study of the role of cosmic feedback in the evolution of the Universe. We discuss the baseline design of LXM and some parallel approaches for some of the key technologies. The baseline sensor technology uses transition-edge sensors, but we also consider an alternative approach using metallic magnetic calorimeters. We discuss the requirements for the instrument, the pixel layout, and the baseline readout design, which uses microwave superconducting quantum interference devices and high-electron mobility transistor amplifiers and the cryogenic cooling requirements and strategy for meeting these requirements. For each of these technologies, we discuss the current technology readiness level and our strategy for advancing them to be ready for flight. We also describe the current system design, including the block diagram, and our estimate for the mass, power, and data rate of the instrument.

Simon R. Bandler↗

NASA NTRS1985

Evaluation of high temperature structural adhesives for extended service, phase 4

The evaluation of three phenylquinoxaline polymers as high temperature structural adhesives is presented. These included an experimental crisskubjabke oiktner (X-PQ) and two experimental materials (PPQ-2501) and (PPQ-HC). Lap shear, crack extension, and climing drum peel specimens were fabricated from all three polymers, and tested after thermal, combined thermal/humidity, and stressed Skydrol exposure. All three polymers generally performed well as adhesives at initial test temperatures from 219K (-67 F) to 505K (450 F) and after humidity exposure. The 644K (700 F) cured test specimens exhibited superior Skydrol resistance and thermal stability at 505K (450 F) when compared to the 602K (625 F) cured test specimens.

Hendricks, C. L.↗

NASA NTRS1987

Evaluation of high temperature structural adhesives for extended service, phase 5

The evaluation of 3 experimental polymers from NASA-Langley and a commercially produced polymer from Mitsui Toatsu Chemicals as high temperature structural adhesives is presented. A polyphenylquinoxaline (PPQ), polyimide (STPI/LaRC-2), and a polyarylene ether (PAE-SO2) were evaluated as metal-to-metal adhesives. Lap shear, crack extension, and climbing drum peel specimens were fabricated from all three polymers and tested after thermal, combined thermal/humidity, and stressed hydraulic fluid (Skydrol) exposure. The fourth polymer, LARC-TPI was evaluated as an adhesive for titanium honeycomb sandwich structure. All three experimental polymers performed well as metal-to-metal adhesives from 219 K (-65 F) to 505 K (450 F), including humidity exposure. Structural adhesive strength was also maintained at 505 K for a minimum of 3000 hours. LaRC-TPI was evaluated as a high temperature (505 K) adhesive for titanium honeycomb sandwich structure. The LaRC-TPI bonding process development concentrated on improving the honeycomb core-to-skin bond. The most promising approach of those evaluated combined a LaRC-TPI polymer solution with a semi-crystalline LaRC-TPI powder for adhesive film fabrication and fillet formation.

Hendricks, C. L.↗

NASA NTRS1975

Applications of a quadratic extended interior penalty function for structural optimization

A quadratic extended interior penalty function formulation especially well suited for second-order unconstrained optimization procedures is presented. Analytical derivatives of constraints and an approximate analysis technique are used. Minimum-mass design results are presented which indicate that the combination of these procedures can help make mathematical programming a useful optimization tool for large-order structural design problems with a large number of design variables and multiple constraints. Examples include statically loaded high- and low-aspect-ratio wings simultaneously subjected to stress, displacement, minimum gage and, in some cases, maximum strain constraints.

Haftka, R. T.↗

NASA NTRS1976

Structure of the extended solar magnetic field and the sunspot cycle variation in cosmic ray intensity

It is proposed that a relation exists between the extent of interplanetary-magnetic-field sectors and observed variations in cosmic-ray intensity at earth. Changes that take place in the sector magnetic fields and solar polar fields during a sunspot cycle are described. It is argued that a geometrical effect arising from changes in sector-field and polar-field extent during sunspot cycles may be the principal cause of the 11-yr modulation of cosmic-ray intensity observed at earth. The fraction of the heliosphere occupied by sector fields is estimated as a function of time through an average sunspot cycle, the solid angle of the heliosphere occupied by the extended solar polar fields is plotted through the same cycle, and monthly averages of observed absolute intensities of primary cosmic rays with a rigidity greater than 0.5 GV are compared with the plot of polar-field extent. It is found that the average sunspot-cycle variation of the solid angle of the extended polar fields is rather similar to the observed variation in the flux of the cosmic rays considered.

Svalgaard, L.↗

NASA NTRS1980

Evaluation of high-temperature structural adhesives for extended service

Candidate high-temperature stable resin formulations were evaluated for adhesive properties when bonded to titanium treated with various surface preparations. The adhesive formulations included LARC-13, NR150 A2, NR150 B2, NR056X, FM-34, HR-602, and polyphenylquinoxaline. Eight titanium surface preparations were compared for resulting bond strength with the candidate adhesives. After initial evaluation, three adhesive systems (comprised of adhesive, primer, and titanium surface preparation) were selected for further screening. The screening (still in progress) includes cure-cycle optimization and bond properties from 219 K (-65 F) to 505 K (450 F), after isothermal aging at 505 K (450 F) up to 15,000 hours, and after humidity aging at 322 K 9120 F)/ 95 percent R. H. for up to 2000 hours. Larger-area bond capability of the three adhesive system can be demonstrated by fabrication of 30.5 cm (12 in) square titanium honeycomb sandwich and metal-to-metal bonded panels.

Hendricks, C. L.↗

NASA NTRS1981

Evaluation of high temperature structural adhesives for extended service

Eight different Ti-6Al-4V surface treatments were investigated for each of 10 candidate resins. Primers (two for each resin) were studied for appropriate cure and thickness and initial evaluation of bond joints began using various combinations of the adhesive resins and surface treatments. Surface failure areas of bonded titanium coupons were analyzed by electron microscopy and surface chemical analysis techniques. Results of surface characterization and failure analysis are described for lap shear bond joints occurring with adhesive systems consisting of: (1) LARC-13 adhesive, Pasa jell surface treatment; (2) LARC-13 adhesive, 10 volt CAA treatment; (3) PPQ adhesive, 10 volt CAA treatment; and (4) PPQ adhesive, 5 volt CAA treatment. The failure analysis concentrated on the 10,000 hr 505K (450 F) exposed specimens which exhibited adhesive failure. Environmental exposure data being generated on the PPQ-10 volt CAA and the LARC-TPI-10 volt CAA adhesive systems is included.

Hill, S. G.↗

NASA NTRS1981

Evaluation of high temperature structural adhesives for extended service

The long term thermal aging data initiated in Phase 1 is reported. All candidate adhesive systems have exhibited significant degradation in bond properties after 505K (450 F) 10,000 hour exposure. Failures appear to be adhesive in the oxide layer. Phase 2 chemical characterization, cure cycle studies, baseline data, preliminary specifications, and environmental exposure data generated on polyphenyquinoxaline is presented. Similar but limited data on LARC-13 and NR056X adhesives is reported.

Hill, S. G.↗

NASA NTRS1983

Evaluation of high temperature structural adhesives for extended service

The preliminary evaluation of crosslinked polyphenyl quinoxaline (X-PPQ), LARC-TPI, ethyl terminated polysulfone (ETPS), and crosslinked polyimide (X-PI) as adhesives is presented. Lap shear strength stability under thermal, combined thermal/humidity, and stressed and unstressed Skydrol exposure was determined. The X-PPQ, LARC-TPI, and X-PI exhibited good adhesive performance at 505K (450 F) after 1000 hours at 505K. These three polymers also performed well after exposure to combined elevated temperature/high humidity, as well as, to Skydrol while under stress. The ETPS exhibited good ambient temperature adhesive properties, but performed poorly under all other exposure conditions, presumably due to inadequate chain extension and crosslinking.

Hill, S. G.↗

NASA NTRS1984

Evaluation of high temperature structural adhesives for extended service

High temperature stable adhesive systems were evaluated for potential Supersonic Cruise Research (SCR) vehicle applications. The program was divided into two major phases: Phase I 'Adhesive Screening' evaluated eleven selected polyimide (PI) and polyphenylquinoxaline (PPQ) adhesive resins using eight different titanium (6Al-4V) adherend surface preparations; Phase II 'Adhesive Optimization and Characterization' extensively evaluated two adhesive systems, selected from Phase I studies, for chemical characterization and environmental durability. The adhesive systems which exhibited superior thermal and environmental bond properties were LARC-TPI polyimide and polyphenylquinoxaline both developed at NASA Langley. The latter adhesive system did develop bond failures at extended thermal aging due primarily to incompatibility between the surface preparation and the polymer. However, this study did demonstrate that suitable adhesive systems are available for extended supersonic cruise vehicle design applications.

Hendricks, C. L.↗

NASA NTRS1984

Evaluation of high temperature structural adhesives for extended service

Hendricks, C. L.↗

NASA NTRS1993

End-effector: Joint conjugates for robotic assembly of large truss structures in space: Extended concepts

Results from NASA/HBCU Grant No. NAG-1-1125 are summarized. Designs developed for model fabrication, exploratory concepts drafted, interface of computer with robot and end-effector, and capability enhancement are discussed.

Brewer, W. V.↗

NASA NTRS1980

Modular space structures

The Extendable Tetrahedral Truss orbiting antenna concept, comprising the use of prefabricated, automatically deployable lattice structures and their subsequent assembly into larger structures suitable for microwave antenna use, is described. It is assumed that the Space Shuttle Orbiter payload bay will be able to accommodate only modular portions of the structural system required, and that the Space Shuttle crew will furnish the manual labor entailed by orbital assembly. It is concluded that a deployable beam module system may be a more elegant design solution than the alternative triangular-module system.

Vaughan, D. H.↗

NASA NTRS1978

Extravehicular activity translation arm (EVATA) study

The preliminary design of a deployable Extravehicular Activity Translation Arm (EVATA) assembly which will allow an EVA crewman to perform tasks in the vicinity of the External TNK (ET) umbilical doors and to inspect most of the underside of the shuttle spacecraft is reported. The concept chosen for the boom structure was the Astro Extendable Support Structure (ESS) which formed the main structure for the Synthetic Aperture Radar (SAR) Antenna System on the SEASAT A spacecraft. This structure is a deployable triangular truss. A comparison of the EVATA and the SEASAT A ESS is shown. The development of status of the ESS is shown. The satellite configuration, the stowed truss load path, and the envelope deployment sequence for the ESS are also shown.

Preiswerk, P. R.↗