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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

(abstract) OMEGA: A Gravitational Wave MIDEX Mission

Among the low frequency (LF) gravitational wave sources that are of astronomical interest are white dwarf binaries, neutron star binaries, massive black hole binaries, and compact stars spiralling into massive black holes. A mission to detect these sources has been proposed to NASA as a possible member of its low-cost, near-term MIDEX mission series. This mission utilizes six tiny miniprobes in high Earth orbit to produce a sensitive Michelson interferometer with million kilometer arms, yielding a strain sensitivity below 10^{-21} at periods longer than a hundred seconds. At this sensitivity, known binary stars will be seen and plausible unknown massive black hole events will be searched for.

gravitational waves binaries black holes neutron s↗
NASA NTRS1994

Thermal Stability Analysis for a Heliocentric Gravitational Radiation Detection Mission

The Laser Interferometer Space Antenna (LISA) mission is designed for detailed studies of low-frequency gravitational radiation. The mission is currently a candidate for ESA's post-Horizon 2000 program. Thermal noise affects the measurement in at least two ways. Thermal variation of the length of the optical cavity to which the lasers are stabilized introduces phase variations in the interferometer signal, which have to be corrected for by using data from the two arms separately.

Laser Interferometer Space Antenna LISA gravitatio↗
NASA NTRS1993

(abstract) System Performance of the Joint Galileo/Mars Observer/Ulysses 1993 Gravitational Wave Experiment

From March 21 to April 11, 1993, the Galileo, Mars Observer, and Ulysses spacecraft were tracked almost continuously in a coincidence experiment to search for low-frequency (~millihertz) gravitational radiation. We report here a first statistical assessment of the noise characteristics of the data, with particular attention to the performance of the radio science instrumentation itself.

gravitational waves radio science noise Doppler ef↗
NASA NTRS1998

Spacecraft Doppler Tracking as a Narrow-Band Detector of Gravitational Radiation

We discuss a filtering technique for reducing the frequency fluctuations due to the troposphere, ionosphere, and mechanical vibrations of the ground antenna in spacecraft Doppler tracking searches for gravitational radiation. This method takes advantage of the sinusoidal behavior of the transfer function to the Doppler observable of these noise sources, which displays sharp nulls at selected Fourier components.

gravitational radiation doppler tracking↗
NASA NTRS1996

Absorption Lines in the Gravitational Lens Systems MG 0414+0534

Spectra of components A1+A2 and B of the gravitational lens system MG0414+0534 taken with the Low Resolution Imaging Spectrograph (LRIS) on the Keck 10 m telescope show that the strong absorption feature seen in a low resoluation spectrum is due to a complex of FeII lines at redshifts near that of the lensed quasar.

Gravitational Lens Systems↗
NASA NTRS1996

MG0414+0534: A Dusty Gravitational Lens

The gravitational lens system MG0414+0534 has an unexceptional four-image lensing geometry; however, the optical counterparts of the radio images are exceedingly red, with spectra unlike that of any previously observed active nucleus.

Gravitational Lens System↗
NASA NTRS2014

Application of a Hough Search for Continuous Gravitational Waves on Data from the Fifth LIGO Science Run

We report on an all-sky search for periodic gravitational waves in the frequency range 50-1000 Hertz with the first derivative of frequency in the range −8.9 × 10(exp −10) Hertz per second to zero in two years of data collected during LIGO's fifth science run. Our results employ a Hough transform technique, introducing a chi(sup 2) test and analysis of coincidences between the signal levels in years 1 and 2 of observations that offers a significant improvement in the product of strain sensitivity with compute cycles per data sample compared to previously published searches. Since our search yields no surviving candidates, we present results taking the form of frequency dependent, 95% confidence upper limits on the strain amplitude h(sub 0). The most stringent upper limit from year 1 is 1.0 × 10(exp −24) in the 158.00-158.25 Hertz band. In year 2, the most stringent upper limit is 8.9 × 10(exp −25) in the 146.50-146.75 Hertz band. This improved detection pipeline, which is computationally efficient by at least two orders of magnitude better than our flagship Einstein@Home search, will be important for 'quicklook' searches in the Advanced LIGO and Virgo detector era.

neutron stars↗
NASA NTRS2014

FY15 Gravitational-Wave Mission Activities Project

The Gravitational-Wave (GW) team at Goddard provides leadership to both the US and international research communities through science and conceptual design competencies. To sustain the US effort to either participate in the GW mission that ESA selected for the L3 opportunity or to initiate a NASA-led mission, the Goddard team will engage in the advancement of the science and the conceptual design of a future GW mission. We propose two tasks: (1) deliver new theoretical tools to help the external research community understand how GW observations can contribute to their science and (2) explore new implementations for laser metrology systems based on techniques from time-domain reflectometry and laser communications.

ESA selected for LS opportunity↗