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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1998

Navigation of the space VLBI mission-HALCA

In February 1997, the Japanese Space Agency ISAS launched the first space VLBI satellite, HALCA, with an 8 meter diameter wire mesh antenna and radio astronomy receivers capable of observing at 1.6, 4.8, and 22 Ghz. In a 560 by 21000 km orbit with a 6 hour period and 31 degree inclination, it observes celestial radio sources in conjunction with a world wide network of ground radio telescopes as part of an international collaborative effort which includes facilities in Japan, the U.S., Canada, Australia, and Europe. JPL is providing tracking and navigation support using a dedicated subnet of 11 meter antennas as well as co-observations using the DSN 70 meter antennas. This paper describes the spacecraft dynamics model and orbit determination strategies developed to meet the stringent trajectory accuracy requirements for generating predictions for the transfer of a stable uplink frequency to the spacecraft and for determining reconstructed orbits for delivery to the NRAO VLBI correlator and the international VLBI science community.

You, Tung Han↗
NASA NTRSDate not supplied

A Worldwide Celebration: International Observe the Moon Night

International Observe the Moon Night is a worldwide public engagement program that has been held annually since 2010. Every autumn, we ask people to observe the Moon in whatever way makes sense to them (via binoculars, telescopes, unaided eye, images, artwork, songs, stories, etc.). The event occurs when the Moon is in or near a first-quarter phase, which provides excellent viewing opportunities along the terminator (the line between night and day), as long shadows place lunar features into great relief. Hundreds of thousands of individuals all around the globe participate in the event as a collective whole, learning about lunar science and exploration, taking part in celestial observations, and honoring cultural and personal connections to the Moon. People participate in a variety of ways, including hosting or attending virtual or in-person events and observing the Moon from home. Participants also have the opportunity to connect with other lunar observers around the world through our Facebook page (facebook.com/observethemoon/), our Flickr group for images (flickr.com/groups/observethemoon2021/), and through the hashtag #ObserveTheMoon across social media platforms.

S L Tiedeken↗
NASA NTRS1984

The pointing system for Space Telescope

This paper provides a description of the Space Telescope (ST) Pointing System (PS), and an overview of the pointing operations and procedures that support celestial observations. It is aimed at indicating to the user-astronomer the ST pointing capabilities and the mechanics of insuring the presence of the correct star in an instrument aperture. The paper begins by summarizing the general requirements regarding image stability and pointing accuracy to which the ST is being designed. This is followed by a description of the PS, in which primary elements are rate gyros, star sensors, reaction wheels, and an onboard digital computer. The Fine Guidance System is the star sensor that provides the precise, long term celestial reference and is given special emphasis, since its autonomous modes are so intimately tied to the acquisition process. A description of a nominal acquisition sequence is given, and some strategies for dealing with acquisition and pointing anomalies are discussed.

Nurre, G. S.↗
NASA NTRS2018

Challenges Beyond the Standard Model: An Examination and Evaluation of Alternatives with Respect to Unsolved Problems in Energetics and Signaling

The standard model of particle physics is regarded as one of the greatest achievements of modern physics. It has successfully predicted the existence of numerous hadrons; e.g. the Higgs Boson, the W and Z Bosons, B mesons, etc. Moreover it accurately models many phenomena such as Beta and Radioactive decay, pair production, hadron mass splitting, and others. In spite of this, the standard model has many shortfalls. For example it fails to account for or explain the presence of dark matter and dark energy. Many alternative models of the substructure of matter etc. have been proposed. Some of these are examined. In addition the strongly related standard model of cosmology, that is the big bang theory, accounts for all observed celestial phenomena. What it cannot do is satisfactorily justify all astrophysical events. As noted, dark matter and dark energy are not well understood yet they are core elements of the big bang model. Many elements of this standard model of cosmology are challenged regularly, yet somehow the community always fits the problems with the model into another mysterious element. This model and others are examined for consistency and reconciliation. Evidence of particles that move faster than the speed of light has long been sought, but remains elusive. Some of the known space-like observations of physics are examined. Potential consequences of such particles are likewise investigated. Some conclusions are drawn with respect to the framework of tachyons in a rational but non-rigorous sense. Finally, some of my ideas are presented, concerning all of the above material. The framework of theories of everything is examined, considering what such a theory requires for validity. Sociological notes on the structure of research in physics are given.

Coxe, Alexander M.↗
DOE OSTI2025

Resolve instrument onboard the X-Ray Imaging and Spectroscopy Mission

We present an overview of the design and in-flight performance of the Resolve soft X-ray spectrometer on the X-Ray Imaging and Spectroscopy Mission that was successfully launched on September 7, 2023, on a JAXA H-IIA rocket from the Tanegashima Space Center of Japan. The instrument has a 36-pixel array of microcalorimeters, 35 of which are at the focus of a high-throughput grazing-incidence X-ray mirror. The instrument has achieved its required operational base temperature of 0.05 K and a spectral resolution of 4.5 eV (FWHM) at 6 keV. The cooling chain was designed to provide a lifetime of at least 3 years in orbit and operate with and without liquid helium to provide redundancy and the longest operational lifetime for the instrument. Early indications are that the cryogen lifetime may reach 6 years with a cryogen-free mode thereafter. A series of onboard X-ray calibration sources produces energy scale calibration lines simultaneously while observing celestial sources. The overall design and in-flight performance of Resolve are described.

Astronomy and AstroPhysics↗
NASA NTRS1976

Soft X-ray observation experiment MA-048

The Apollo Soyuz Test Project Soft X-ray Experiment was designed to observe celestial X-ray sources in the energy range from 0.1 to 10 kiloelectronvolts. The instrument that was used in the experiment obtained energy and fast timing data to characterize both the spectrum and the variability of known X-ray sources. Data were obtained on approximately 12 sources. During the mission, the instrument developed an intermittent high voltage discharge problem that resulted in the loss of approximately 75 percent of the anticipated data, including the scans intended for mapping of the low energy diffuse X-ray background.

Shulman, S.↗
NASA NTRS1984

Space Shuttle mission extension capability

Space Shuttle missions are currently limited to 11 days, primarily due to depletion of the power reactants (hydrogen and oxygen). A power system Mission Extension Kit (MEK) is described which could provide the capability to stay on orbit 10 additional days. These extra days would benefit Space Station construction and missions such as materials processing, earth and celestial observation, and life science studies (Spacelab). Other constraints to longer missions which may dictate minor Orbiter modifications will be discussed. The power system MEK is particularly desirable because of its existing flight qualified hardware which can be delivered within 3 to 4 years.

Fraser, W. M., Jr.↗
NASA NTRS1991

Killer rocks and the celestial police - The search for near-earth asteroids

The discovery of asteroids near the earth as the result of search programs is detailed with attention given to methods for locating, tracking, and identifying asteroids. The concept of 'prediscovery' is discussed in which new asteroids are tracked backward in time through previous celestial observational data. The need for more comprehensive programs is identified in order to locate objects that present a clear danger of colliding with the earth.

Yeomans, Donald K.↗
NASA NTRS1994

Laser Metrology System For A Segmented Telescope Reflector

Report describes proposed laser metrology system in far-infrared telescope with segmented primary reflector. Telescope to be flown in outer space and used to observe celestial objects. Laser metrology system mounted on structure that supported secondary telescope reflector and measures relative positions and alignments of segments of primary reflector. System used in pointing as well as in maintaining surface figure.

Lau, Kenneth H.↗
NASA NTRS1994

Space based astronomy: Teacher's guide with activities

This curriculum guide uses hands-on activities to help students and teachers understand the significance of space-based astronomy - astronomical observations made from outer space. The guide contains few of the traditional activities found in many astronomy guides such as constellation studies, lunar phases, and planetary orbits. Instead, it tells the story of why it is important to observe celestial objects from outer space and how to study the entire electromagnetic spectrum. The guide begins with a survey of astronomy related NASA spacecraft. This is followed by a collection of activities in four units: (1) the atmospheric filter; (2) the electromagnetic spectrum; (3) collecting electromagnetic radiation; and (4) down to Earth. A curriculum index identifies the curriculum areas each activity addresses. The guide concludes with a glossary, reference list, a NASA Resources list, and an evaluation card. It is designed for students in grades 5 through 8.

Rosenberg, Carla B.↗
NASA NTRS1996

Actuators Help Correct For Gravitational Bending Of Antenna

Force-actuator scheme devised to help correct for decrease, caused by gravitational bending, in gain of 34-m-diameter paraboloidal microwave antenna reflector used for tracking distant spacecraft and observing celestial radio sources. Also applicable to other antennas bending significantly under own weight, with consequent degradation of performance.

Levy, Roy↗
NASA NTRS1999

STS-93 Flight Day 4 Highlights and Crew Activities

The five astronauts aboard the Space Shuttle Columbia began their fourth flight day preparing to make additional celestial observations through the shuttle's windows and continue work with a variety of instruments. Pilot Jeff Ashby and Mission Specialists Steve Hawley and Michael Tognini set up an exercise treadmill and the Treadmill Vibration Information System (TVIS) which measures vibrations and changes in microgravity levels caused by on-orbit workouts. Astronomer Hawley again made observations of Venus, Jupiter and the Moon with the Southwest Ultraviolet Imaging System (SWUIS) as Commander Eileen Collins and Pilot Jeff Ashby put the shuttle in the proper orientation for his observations. Tognini and Coleman checked the bioprocessing experiments, and harvested mouse-ear cress plants as part of the Plant Growth in Microgravity experiment. Collins and Ashby once again fired the shuttle's engines so that the sensors of the Midcourse Space Experiment (MSX) satellite were able to collect ultraviolet, infrared and visible light data. Columbia was orbiting at an altitude of 182 statute miles with all of its systems in excellent condition.

Source record↗
NASA NTRS2001

A General Description and Current Status of Chandra

The third of NASA's four Great Observatories, the Chandra X-ray Observatory, was launched aboard the Shuttle Columbia on July 23, 1999. Using an Inertial Upper Stage and an internal propulsion system, Chandra was raised to a highly elliptical orbit ranging from 10,000 km to 140,000 km. After a successful activation of all spacecraft, telescope and science instrument systems, Chandra began observing celestial targets about 18 months ago. From the start, Chandra has provided spectacular images and spectra for essentially all types of astronomical objects including stars, supernova remnants, normal and active galaxies, and clusters of galaxies. High spatial resolution X-ray images and high resolution X-ray spectra continue to provide 'surprises" essentially every day. The current Observatory status and selected science highlights will be presented in this talk.

Tananbaum, Harvey↗
NASA NTRS2001

Space-Based Astronomy: An Educator Guide with Activities for Science, Mathematics, and Technology Education

If you go to the country, far from city lights, you can see about 3,000 stars on a clear night. If your eyes were bigger, you could see many more stars. With a pair of binoculars, an optical device that effectively enlarges the pupil of your eye by about 30 times, the number of stars you can see increases to the tens of thousands. With a medium-sized telescope with a light-collecting mirror 30 centimeters in diameter, you can see hundreds of thousands of stars. With a large observatory telescope, millions of stars become visible. This curriculum guide uses hands-on activities to help students and teachers understand the significance of space-based astronomy--astronomical observations made from outer space. It is not intended to serve as a curriculum. Instead, teachers should select activities from this guide that support and extend existing study. The guide contains few of the traditional activities found in many astronomy guides such as constellation studies, lunar phases, and planetary orbits. It tells, rather, the story of why it is important to observe celestial objects from outer space and how to study the entire electromagnetic spectrum. Teachers are encouraged to adapt these activities for the particular needs of their students. When selected activities from this guide are used in conjunction with traditional astronomy curricula, students benefit from a more complete experience.

Vogt, Gregory L.↗
NASA NTRS2016

The ASTRO-H SXT Performance to the Large Off-Set Angles

The X-ray astronomy satellite ASTRO-H, which is the 6th Japanese X-ray astronomy satellite and is renamed Hitomi after launch, is designed to observe celestial X-ray objects in a wide energy band from a few hundred eV to 600 keV. The Soft X-ray Telescopes (SXTs) onboard ASTRO-H play a role of collecting and imaging X-rays up to approximately 12 keV. Although the field of view of the SXT is approximately 15' (FWHM), due to the thin-foil-nested Wolter-I type optics adopted in the SXTs, X-rays out of the field of view can reach the focal plane without experiencing a normal double reflection. This component is referred to as 'stray light'. Owing to investigation of the stray light so far, 'secondary reflection' is now identified as the main component of the stray light, which is composed of X-rays reflected only by secondary reflectors. In order to cut the secondary reflections, a 'pre-collimator' is equipped on top of the SXTs. However, we cannot cut all the stray lights with the pre-collimator in some off-axis angle domain. In this study, we measure the brightness of the stray light of the SXTs at some representative off-axis angles by using the ISAS X-ray beam line. ASTRO-H is equipped with two modules of the SXT; one is for the Soft X-ray Spectrometer (SXS), an X-ray calorimeter, and the other is for the Soft X-ray Imager (SXI), an X-ray CCD camera. These SXT modules are called SXT-S and SXT-I, respectively. Of the two detector systems, the SXI has a large field of view, a square with 38' on a side. To cope with this, we have made a mosaic mapping of the stray light at a representative off-axis angle of 30' in the X-ray beam line at the Institute of Space and Astronautical Science. The effective area of the brightest secondary reflection is found of order approximately 0.1% of the on-axis effective area at the energy of 1.49 keV. The other components are not so bright (less than 5 x 10(exp -4) times smaller than the on-axis effective area). On the other hand, we have found that the effective area of the stray light in the SXS field of view (approximately 3' x 3') at large off-axis angles (greater than 15') are approximately 1(exp -4) times smaller than the on-axis effective area (approximately 590 sq cm at 1.49 keV).

X-rays↗
NASA NTRS2018

Armstrong Flight Research Center Research Technology and Engineering 2017

I am delighted to present this report of accomplishments at NASA's Armstrong Flight Research Center. Our dedicated innovators possess a wealth of performance, safety, and technical capabilities spanning a wide variety of research areas involving aircraft, electronic sensors, instrumentation, environmental and earth science, celestial observations, and much more. They not only perform tasks necessary to safely and successfully accomplish Armstrong's flight research and test missions but also support NASA missions across the entire Agency. Armstrong's project teams have successfully accomplished many of the nation's most complex flight research projects by crafting creative solutions that advance emerging technologies from concept development and experimental formulation to final testing. We are developing and refining technologies for ultra-efficient aircraft, electric propulsion vehicles, a low boom flight demonstrator, air launch systems, and experimental x-planes, to name a few. Additionally, with our unique location and airborne research laboratories, we are testing and validating new research concepts. Summaries of each project highlighting key results and benefits of the effort are provided in the following pages. Technology areas for the projects include electric propulsion, vehicle efficiency, supersonics, space and hypersonics, autonomous systems, flight and ground experimental test technologies, and much more. Additional technical information is available in the appendix, as well as contact information for the Principal Investigator of each project. I am proud of the work we do here at Armstrong and am pleased to share these details with you. We welcome opportunities for partnership and collaboration, so please contact us to learn more about these cutting-edge innovations and how they might align with your needs.

yearbook↗