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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 1,675 records · Page 93
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Mars Relay Satellite: Key to Enabling Low-Cost Exploration Missions

Recently, there has been increasing evidence of a renewed focus on Mars exploration both by NASA and the international community. The thrust of this renewed interest appears to be manifesting itself in numerous low-cost missions employing small, light weight elements, which utilize advanced technologies including integrated microelectronics. A formidable problem facing these low-cost missions is communications with Earth. Providing adequate direct-link performance has very significant impacts on spacecraft power, pointing, mass and overall complexity. Additionally, for elements at or near the surface of Mars, there are serious connectivity constraints, especially at higher latitudes, which lose view of Earth for up to many months at a time. This paper will discuss the role a Mars relay satellite can play in enabling and enhancing low-cost missions to Mars...

Hastrup, R.↗
NASA NTRS1998

The HST Key Project on the Extragalactic Distance Scale

We report the detection of Cepheids and a new distance to the spiral galaxy NGC 2541, based on data obtained with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope (HST).

Cepheids spiral galaxy Hubble Space Telescope Extr↗
NASA NTRS1996

The HST Key Project on the Extragalactic Distance Scale VI. The Cepheids in NGC925

We report the detection of Cepheid Variable stars in the barred spiral galaxy NGC925, using the Hubble Space Telescope (HST) Wide Field and Planetary Camera 2 (WFPC2). Twelve V (F555W), four I (F814W) and three B (F439W) epochs of cosmic ray split observations were obtained. Eighty Cepheids were discovered, with periods from 6 to +-80 days. Light curves of the Cepheids are presented, and their corresponding period-luminosity diagrams are discussed.

Cepheids Cepheid Cepheid Variable stars barred spi↗
NASA NTRS2007

Key and Driving Requirements for the Juno Payload of Instruments

The Juno Mission was selected in the summer of 2005 via NASA's New Frontiers competitive AO process (refer to http://www.nasa.gov/home/hqnews/2005/jun/HQ_05138_New_Frontiers_2.html). The Juno project is led by a Principle Investigator based at Southwest Research Institute [SwRI] in San Antonio, Texas, with project management based at the Jet Propulsion Laboratory [JPL] in Pasadena, California, while the Spacecraft design and Flight System Integration are under contract to Lockheed Martin Space Systems Company [LM-SSC] in Denver, Colorado. the payload suite consists of a large number of instruments covering a wide spectrum of experimentation. The science team includes a lead Co-investigator for each one of the following experiments: A Magnetometer experiment (consisting of both a FluxGate Magnetometer (FGM) built at Goddard Space Flight Center GSFC] and a Scalar Helium Magnetometer (SHM) built at JPL, a MicroWave Radiometer (MWR) also built at JPL, a Gravity Science experiment (GS) implemented via the telecom subsystem, two complementary particle instruments (Jovian Auroral Distribution Experiment, JADE developed by SwRI and Juno Energetic-particle Detector Instrument, JEDI from the Applied Physics Lab (APL)--JEDI and JADE both measure electrons and ions), an Ultraviolet Spectrometer (UVS) also developed at SwRI, and a radio and plasma (WAVES) experiment (from the University of Iowa). In addition, a visible camera (JunoCam) is included in the payload to facilitate education and public outreach (designed & fabricated by Malin Space Science Systems [MSSS]).

challenges↗
NASA NTRS2007

Prediction of Geomagnetic Activity and Key Parameters in High-latitude Ionosphere

Prediction of geomagnetic activity and related events in the Earth's magnetosphere and ionosphere are important tasks of US Space Weather Program. Prediction reliability is dependent on the prediction method, and elements included in the prediction scheme. Two of the main elements of such prediction scheme are: an appropriate geomagnetic activity index, and an appropriate coupling function (the combination of solar wind parameters providing the best correlation between upstream solar wind data and geomagnetic activity). We have developed a new index of geomagnetic activity, the Polar Magnetic (PM) index and an improved version of solar wind coupling function. PM index is similar to the existing polar cap PC index but it shows much better correlation with upstream solar wind/IMF data and other events in the magnetosphere and ionosphere. We investigate the correlation of PM index with upstream solar wind/IMF data for 10 years (1995-2004) that include both low and high solar activity. We also have introduced a new prediction function for the predicting of cross-polar-cap voltage and Joule heating based on using both PM index and upstream solar wind/IMF data. As we show such prediction function significantly increase the reliability of prediction of these important parameters. The correlation coefficients between the actual and predicted values of these parameters are approx. 0.9 and higher.

Khazanov, George V.↗