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At least 37 records · Page 2

Wide-field direct CCD observations supporting the Astro-1 Space Shuttle mission's Ultraviolet Imaging Telescope

Wide field direct CCD observations are being obtained to support and complement the vacuum-ultraviolet (VUV) images provided by Astro's Ultraviolet Imaging Telescope (UIT) during a Space Shuttle flight in December 1990. Because of the wide variety of projects addressed by UIT, the fields observed include (1) galactic supernova remnants such as the Cygnus Loop and globular clusters such as Omega Cen and M79; (2) the Magellanic Clouds, M33, M81, and other galaxies in the Local Group; and (3) rich clusters of galaxies, principally the Perseus cluster and Abell 1367. Ground-based observations have been obtained for virtually all of the Astro-1 UIT fields. The optical images allow identification of individual UV sources in each field and provide the long baseline in wavelength necessary for accurate analysis of UV-bright sources. To facilitate use of our optical images for analysis of UIT data and other projects, we plan to archive them, with the UIT images, at the National Space Science Data Center (NSSDC), where they will be universally accessible via anonymous FTP. The UIT, one of three telescopes comprising the Astro spacecraft, is a 38-cm f/9 Ritchey-Chretien telescope on which high quantum efficiency, solar-blind image tubes are used to record VUV images on photographic film. Five filters with passbands centered between 1250A and 2500A provide both VUV colors and a measurement of extinction via the 2200A dust feature. The resulting calibrated VUV pictures are 40 arcminutes in diameter at 2.5 arcseconds resolution. The capabilities of UIT, therefore, complement HST's WFPC: the latter has 40 times greater collecting area, while UIT's usable field has 170 times WFPC's field area.

Hintzen, Paul↗

Intrinsic Line Shape Measurements of the XRS Instrument on Astro-E2

The XRS instrument on the Astro-E2 observatory contains a substantially improved microcalorimeter array over the Astro-E mission. In addition to roughly a factor of 2 improvement in the detector resolution at 6 keV, the detector response is shown to be almost perfectly gaussian. We have made measurements of the detector response of the flight instrument, using a double crystal monochrometer at 4 and 8 keV, a 55-Fe internal conversion source, and x-ray induced fluorescence from a number of targets including Ti, Cu, and GaAs. The detector response has been measured to be entirely gaussian to at least 2 orders of magnitude down from the peak of the line or line complex. This is in sharp contrast to the results from the XRS on Astro-E where many channels exhibited excess counts on the high energy side of the spectral lines. Here we present details of the line shape measurement as well as the detector response as measured during the XRS ground calibration including details of the line fits and line models.

Porter, F. Scott↗

Astro-D Prelaunch Mission Operation Report (MOR)

The Prelaunch Mission Operation Report for the Astro-D mission is enclosed for your information. Astro-D is a Japanese-led program involving the United States as a participating partner. The Japanese Institute of Space and Astronautical Science (ISAS) provides overall program management, the launch vehicle, the spacecraft, and two Gas Scintillation Imaging System detectors. NASA is providing four nested, thin-foil, grazing-incidence telescope mirrors and two X-ray charged-coupled device solid-state detectors. NASA also provides telemetry tracking support using Deep Space Network ground stations. In return for its scientific instrument contribution, the U.S. will receive 15 percent of the observing time and will share an additional 25 percent for collaborative U.S./Japan scientific investigations. Launch is scheduled for mid- February 1993 from the ISAS launch center near Kagoshima in southern Japan. This MOR: (a) describes the NASA objectives for the Astro-D mission; (b) provides brief descriptions of the spacecraft and its scientific instruments; (c) provides a chronology of launch and deployment; and (d) describes the ground operation elements that support the mission. .

Source record↗

Ground-Based X-Ray Calibration of the Astro-H/Hitomi Soft X-Ray Telescopes

We present the summary of the on-ground calibration of two soft x-ray telescopes (SXT-I and SXT-S), developed by NASA's Goddard Space Flight Center (GSFC), onboard Astro-H/Hitomi. After the initial x-ray measurements with a diverging beam at the GSFC 100-meter beamline, we performed the full calibration of the x-ray performance, using the 30-meter x-ray beamline facility at the Institute of Space and Astronautical Science of Japan Aerospace Exploration Agency in Japan. We adopted a raster scan method with a narrow x-ray pencil beam with a divergence of approximately 15 arc secs. The on-axis effective area (EA), half-power diameter, and vignetting function were measured at several energies between 1.5 and 17.5 kiloelectronvolts. The detailed results appear in tables and figures in this paper. We measured and evaluated the performance of the SXT-S and the SXT-I with regard to the detector-limited field-of-view and the pixel size of the paired flight detector, i.e., SXS and the SXI, respectively. The primary items measured are the EA, image quality, and stray light for on-axis and off-axis sources. The accurate measurement of these parameters is vital to make the precise response function of the ASTRO-H SXTs. This paper presents the definitive results of the ground-based calibration of the ASTRO-H SXTs.

Iizuka, Ryo↗

Astro-animation - A case study of art and science education

Art and science are different ways of exploring the world, but together they have the potential to be thought-provoking, facilitate a science‐society dialogue, raise public awareness of science and develop an understanding of art. For several years, we have been teaching an astro-animation class at the Maryland Institute College of Art as a collaboration between students and NASA scientists. Working in small groups, the students create short animations based on the research of the scientists who are going to follow the projects as mentors. By creating these animations, students bring the power of their imagination to see the research of the scientists through a different lens. Astro-animation is an undergraduate-level course jointly taught by an astrophysicist and an animator. In this article, we present the motivation behind the class, describe the details of how it is carried out and discuss the interactions between artists and scientists. We describe how such a programme offers an effective way for art students, not only to learn about science but to have a glimpse of ‘science in action’. The students have the opportunity to become involved in the process of science as artists, as observers first and potentially through their own art research. Every year, one or more internships at NASA Goddard Space Flight Center have been available for our students in the summer. Two students describe their experiences undertaking these internships and how science affects their creation of animations for this programme and in general. We also explain the genesis of our astro-animation programme, how it is taught in our animation department and we present the highlights of an investigation of the effectiveness of this programme we carried out with the support of an NEA research grant. In conclusion, we discuss how the programme may grow in new directions, such as contributing to informal STE(A)M learning.

Laurence Arcadias↗

ASTRO: Facilitating Advancements in Low-Impact Solar Research, Deployment, and Dissemination

The U.S. Department of Energy's (DOE) InSPIRE project evaluates opportunities for cost reductions and assesses the environmental compatibility of solar energy technologies through low environmental impact designs and approaches. To achieve the project's aim, DOE brings together researchers from the National Renewable Energy Laboratory, Argonne National Laboratory, universities, local governments, environmental groups, and solar industry partners to conduct field-based research complemented by foundational analytical studies. The Agriculture and Solar Together: Research Opportunities (ASTRO) advisory group members come from across the United States and represent leading solar industry partners, state agencies, vegetation management companies, and other organizations focused on research, food and agriculture, and the environment. The ASTRO group of engaged advisors is a complementary combination of organizations creating positive feedback loops that spark and solidify new connections, accelerate information dissemination, and magnify the impact of the InSPIRE project and associated low-impact solar research initiatives.

14 SOLAR ENERGY↗

Calibration of the Soft X-ray Telescopes (SXT) Onboard the ASTRO-H Satellite

ASTRO-H is an astrophysics satellite dedicated for non-dispersive X-ray spectroscopic study on selective celestial X-ray sources. Among the onboard instruments there are four Wolter-I X-ray mirrors of their reflectors' figure in conical approximation. Two of the four are soft X-ray mirrors, of which the energy range is from a few hundred eV to 15 keV. The focal point instruments will be a calorimeter (SXS) and a CCD camera (SXI), respectively. The mirrors were in quadrant configuration with photons being reflected consecutively in the primary and secondary stage before landing on the focal plane of 5.6 m away from the interface between the two stages. The reflectors of the mirror are made of heat-formed aluminum substrate of the thickness gauged of 152 m, 229 m, and 305 m of the alloy 5052 H-19, followed by epoxy replication on gold-sputtered smooth Pyrex cylindrical mandrels to acquire the X-ray reflective surface. The epoxy layer is 10 m nominal and surface gold layer of 0.2 m. Improvements on angular response over its predecessors, e.g. Astro-E1/Suzaku mirrors, come from error reduction on the figure, the roundness, and the grazing angle/radius mismatching of the reflecting surface, and tighter specs and mechanical strength on supporting structure to reduce the reflector positioning and the assembly errors. Each soft x-ray telescope (SXT), FM1 or FM2, were integrated from four independent quadrants of mirrors. The stray-light baffles, in quadrant configuration, were mounted onto the integrated mirror. Thermal control units were attached to the perimeter of the integrated mirror to keep the mirror within operating temperature in space. The completed instrument went through a series of optical alignment, thus made the quadrant images confocal and their optical axes in parallel to achieve highest throughput possible. Environmental tests were carried out, and optical quality of the telescopes has been confirmed. The optical and x-ray calibrations also include: angular resolution, effective area in the energy range of ~ 0.4 - 12keV, off-axis response, etc. Some of those are being carried out by our counterpart at JAXA/ISAS, Japan. We report the calibration results of the FM1 and FM2 that were obtained at Goddard Space Flight Center.

ASTRO-H Satellite↗

First Peek of ASTRO-H Soft X-Ray Telescope (SXT) In-Orbit Performance

ASTRO-H (Hitomi) is a Japanese X-ray astrophysics satellite just launched in February, 2016, from Tanegashima, Japan by a JAXA's H-IIA launch vehicle. It has two Soft X-ray Telescopes (SXTs), among other instruments, that were developed by the NASA Goddard Space Flight Center in collaboration with ISAS/JAXA and Nagoya University. One is for an X-ray micro-calorimeter instrument (Soft X-ray Spectrometer, SXS) and the other for an X-ray CCD camera (Soft X-ray Imager, SXI), both covering the X-ray energy band up to 15 keV. The two SXTs were fully characterized at the 30-m X-ray beam line at ISAS/JAXA. The combined SXT+SXS system effective area is about 250 and 300 cm(exp 2) at 1 and 6 keV, respectively, although observations were performed with the gate valve at the dewar entrance closed, which blocks most of low energy X-rays and some of high energy ones. The angular resolution for SXS is 1.2 arcmin (Half Power Diameter, HPD). The combined SXT+SXI system effective area is about 370 and 350 cm (exp 2) at 1 and 6 keV, respectively. The angular resolution for SXI is 1.3 arcmin (HPD). The both SXTs have a field of view of about 16 arcmin (FWHM of their vignetting functions).The SXT+SXS field of view is limited to 3 x 3 arcmin by the SXS array size. In-flight data available to the SXT team was limited at the time of this conference and a point-like source data is not available for the SXT+SXS. Although due to lack of attitude information we were unable to reconstruct a point spread function of SXT+SXI, according to RXJ1856.5-3754 data, the SXT seems to be working as expected in terms of imaging capability. As for the overall effective area response for both SXT+SXS and SXT+SXI, consistent spectral model fitting parameters with the previous measurements were obtained for Crab and G21.5-0.9 data. On the other hand, their 2-10 keV fluxes differ by about 20% at this point. Calibration work is still under progress. The SXT is the latest version of the aluminum foil X-ray mirror, which is extremely light-weight and very low cost, yet produces large effective area over a wide energy-band. Its area-mass ratio is the largest, 16 cm(exp 2)/kg, among ASTRO-H, Chandra, and XMM-Newton mirrors. The aluminum foil mirror is a still compelling technology depending on the mission science goal.

X-rays↗

The ASTRO-1 preliminary design review coupled load analysis

Results of the ASTRO-1 preliminary design review coupled loads analysis are presented. The M6.0Y Generic Shuttle mathematical models were used. Internal accelerations, interface forces, relative displacements, and net e.g., accelerations were recovered for two ASTRO-1 payloads in a tandem configuration. Twenty-seven load cases were computed and summarized. Load exceedences were found and recommendations made.

Mcghee, D. S.↗

The Astro-1 mission

The Astro-1 mission was to be launched in March 1986 for an effective duration of 7 days, chosen to overlap spacecraft encounters with Halley's Comet, i.e., Vega-2 (on 9 March) and Giotto (on 13/14 March). The ultraviolet instrument complement while not designed with cometary research as the prime objective, was well suited to the study of comets. The opportunity of an extended mission during the time of the spacecraft encounters of Halley's Comet offered an extraordinary opportunity for a synergistic interaction between the intercept spacecraft, the Earth-orbital Astro-1 mission, and ground-based observations. The addition of visual-wavelength, wide-field cameras would enhance the scientific return of the mission. Loss of Challenger cancelled the mission.

Brandt, J. C.↗

ASTROS - A sub-arcsec CCD star tracker

The design and application of ASTROS (Advanced Star and Target Reference Optical Sensor) are described, with emphasis on performance test results acquired with a prototype system. The ASTROS tracker provides extremely precise measurements of star image coordinates as inputs to the Image Motion Compensation (IMC) system used to stabilize the science instrument focal planes. Performance levels achieved are dramatic improvements over the levels achieved with image dissector designs with comparable fields of view.

Stanton, R. H.↗

Acquisition and track algorithms for the Astros star tracker

The Astros star tracker has been designed for an employment with the Space Shuttle. An achievement of the performance levels needed has required critical trade-offs between the hardware design and the control algorithms. This paper provides a description of the development of the acquisition and track algorithms. Attention is given to an Astros system overview, a system firmware description, cluster evaluation, guide star selection, exposure time determination, video data input, update interval timing, exposure time sequencing full frame video A/D conversion, analog threshold for acquisition, minimum threshold determination, and the theoretical basis for the track algorithm.

Shalom, E.↗

ASTROS: A multidisciplinary automated structural design tool

ASTROS (Automated Structural Optimization System) is a finite-element-based multidisciplinary structural optimization procedure developed under Air Force sponsorship to perform automated preliminary structural design. The design task is the determination of the structural sizes that provide an optimal structure while satisfying numerous constraints from many disciplines. In addition to its automated design features, ASTROS provides a general transient and frequency response capability, as well as a special feature to perform a transient analysis of a vehicle subjected to a nuclear blast. The motivation for the development of a single multidisciplinary design tool is that such a tool can provide improved structural designs in less time than is currently needed. The role of such a tool is even more apparent as modern materials come into widespread use. Balancing conflicting requirements for the structure's strength and stiffness while exploiting the benefits of material anisotropy is perhaps an impossible task without assistance from an automated design tool. Finally, the use of a single tool can bring the design task into better focus among design team members, thereby improving their insight into the overall task.

Neill, D. J.↗

A mass additive technique for modal testing as applied to the Space Shuttle ASTRO-1 payload

Traditionally, a fixed base modal test has been performed as a means of verifying the coupled loads math model for Space Shuttle flight payloads. An alternate method, a free-free configured payload using mass loaded boundary conditions, is presented as a means of verifying the coupled loads model of the ASTRO-1 flight payload. This method allows evaluation of the influence of local load paths into the frequency range of the free-free test. The method is cost effective and does not contaminate the modal test results with fixture coupled modes or boundary condition uncertainties. This paper describes the mass additive modal test technique as applied to the Space Shuttle ASTRO-1 flight payload.

Coleman, A. D.↗

Astro - Observatory in a Shuttle

This paper discusses the Astro, a UV and X-ray observatory designed for the Space Shuttle Columbia, which is scheduled for the May 7, 1990 launch. Astro's four telescopes and their operation are described. They are the Hopkins Ultraviolet Telescope, the Wisconsin Ultraviolet Photo-Polarimeter Experiment, the Ultraviolet Imaging Telescope, and the Broad Band X-ray Telescope. Attention is also given to the mission plan and to the ground operations.

Blair, William P.↗

The Astro-1 Observatory mission

This paper describes the NASA's Astro-1 Observatory mission. The three ultraviolet (UV) telescopes and one X-ray telescope that make up this Spacelab mission will observe objects in the solar system, including comets and the outer planets, objects within the Milky Way Galaxy, and high-energy extragalactic objects such as quasi-stellar objects and active galaxies. While briefly discussing the science objectives of the mission, the paper focuses on the history of the mission, the Spacelab hardware assembled by the George C. Marshall Space Flight Center (MSFC) to carry the telescopes into orbit, and the complexities of the systems supporting that payload. Also discussed are the dimensions and capabilities of the Hopkins Ultraviolet Telescope, the Ultraviolet Imaging Telescope, the Wisconsin Ultraviolet Photopolarimeter Experiment, and the Broad Band X-Ray Telescope, all of which will coobserve a number of targets to generate comprehensive data in both the ultraviolet and X-ray ranges of the spectrum. The Astro-1 mission operations are described, and the cooperative functions of other NASA centers are reported.

Jones, Jack↗

Large scale optimization using ASTROS: An overview

Interest in interdisciplinary systems is widespread around the world. A number of structural optimization systems are being developed and tested. Some examples are listed here. ASOP, FASTOP, and TSO are programs developed for the Air Force Flight Dynamics Laboratory during the seventies. These programs established the feasibility of integrating various disciplines. The program 'STARS' is basically a structural optimization system developed by the Royal Aircraft Establishment (RAE) in England. At present, it is being enhanced to include aeroelasticity. 'LAGRANGE' is an optimization system developed by MBB in Germany. ELFINI is a similar system developed in France. It is being marketed in the U.S. as well as other countries. The Automated STRuctural Optimization System (ASTROS) was developed for the Flight Dynamics Directorate of Wright Laboratory. The ASTROS system is described in viewgraph form.

Venkayya, Vipperia B.↗

Orbiter attitude design for the Astro-1 Spacelab mission

The methods utilized to design orbiter attitudes that satisfied the various Space Shuttle program and payload constraints of the Astro-1 Spacelab astronomy mission are described. The premission methods developed for attitude design and how those methods were applied to accomplish the large amount of real-time replanning required during the flight are presented. Some of the attitude concerns for Astro-1 included orbiter window thermal constraints, two separate telescope fields-of-view, tracking and data relay satellite Ku-band access, and telescope sun avoidance.

Olsen, C. D.↗