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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

The NASA SETI program at JPL

The NASA All Sky Survey strategy for detecting signals of extraterrestrial origin is examined. The All Sky Survey observes the entire celestial sphere, covers a frequency range of 1-10 Ghz, and has spatial direction and frequency coverage. The survey time is dependent on the area of the sky surveyed, the telescope diameter, scan rate, the angular separation of the scans, the bandwidth of the receiver, and the frequency coverage. The distance at which a transmitter can be detected for a given sensitivity is analyzed. The interaction between scan strategy and various accumulation strategies and its effect on the sensitivity of the survey are investigated using field tests. A diagram of the SETI Sky Survey observational system is provided.

Gulkis, Sam↗
NASA NTRS1986

Radio astronomy aspects of the NASA SETI Sky Survey

The application of SETI data to radio astronomy is studied. The number of continuum radio sources in the 1-10 GHz region to be counted and cataloged is predicted. The radio luminosity functions for steep and flat spectrum sources at 2, 8, and 22 GHz are derived using the model of Peacock and Gull (1981). The relation between source number and flux density is analyzed and the sensitivity of the system is evaluated.

Klein, Michael J.↗
NASA NTRS1986

Manifestation of intelligence implications for SETI

The objectives of the SETI projects are discussed. Life, intelligence, and sapience are defined in order to characterize the phenomena. Dissipation and coherence are useful characteristics for detection. Consideration is given to electromagnetically observable phenomena, in particular spatial coherence.

Kuiper, T. B. H.↗
NASA NTRS1988

New CCIR report on SETI

Since 1978, the reports and recommendations of the Comite Consultatif International des Radiocommunications (CCIR) have included a document describing SETI (the Search for Extraterrestrial Intelligence) in the context of radio frequency management. A new report to replace the old one was adopted by a CCIR study group; both reports were written at JPL. Following introductory and background material, the text of the new report is given.

Degroot, N. F.↗
NASA NTRS1987

The windows of SETI - Frequency and time in the search for extraterrestrial intelligence

Since interstellar travel is not economically possible on the time scale of a human lifetime, communication with extraterrestrials can be achieved only by sending some form of energy or matter across space; photons (electromagnetic waves) are best. Of particular interest to SETI is the region from about 1,000-60,000 MHz known as the free-space microwave window. During the course of NASA's Cyclops program, it was pointed out that the hydrogen and hydroxyl lines bounded a band in which there were no other known lines. The threatened loss of the microwave window to earth-based services is discussed.

Oliver, Bernard M.↗
NASA NTRS1988

The Serendip piggyback SETI project

The Serendip project, an ongoing SETI program of monitoring and processing broadband radio signals acquired by existing radio astronomy observatories, are summarized. Serendip operates in a piggyback mode, making use of whatever observing plan is under way at its host observatory. The Serendip system at NRAO and the signature detection and identification techniques used by the project are described. The method used to reject terrestrial interference is discussed.

Lampton, Michael↗
NASA NTRS1991

Wideband waveguide polarizer development for SETI

A wideband polarizer for the Deep Space Network (DSN) 34 meter beam waveguide antenna is needed for the Search for Extraterrestrial Intelligence (SETI) project. The results of a computer analysis of a wideband polarizer are presented.

Lee, P.↗
NASA NTRS1991

Cultural aspects of SETI

The paper presents a broad range of issues that raise important questions about the search for exterrestrial life forms or intelligence. The history of the concept of plurality of inhabited worlds is reviewed, and disciplinary areas are cited that are considered crucial for SETI. Such issues involve analogs of the discovery of ETI, immediate responses to such detections, and the significance of journalistic and media response. The responses of religion is also considered, and it is suggested that humankind respond to the discovery of ETI with a single voice and message. The issues discussed demonstrate the need for explicit protocols that would be followed after any discovery of the types discussed.

Billingham, John↗
NASA NTRS1992

SETI in the future - Toward other possible searches

The future prospects of SETI as a scientific endeavor, both in its own right and with respect to the side benefits to science and society, are discussed. Specifically, the consequences of a successful detection and the prospects for follow-on studies in exobiology are addressed.

Rummel, John D.↗
NASA NTRS1993

Search for Extraterrestrial Intelligence (SETI)

Various aspects of project SETI are discussed. Some of the topics discussed include spectrum analyzers, signal processing, sky surveys, radiotelescopes, high resolution microwave survey, Deep Space Network, and signal detection.

Billingham, John↗
NASA NTRS1994

A SETI Search of Nearby Solar-Type Stars at the 203-GHz Positronium Hyperfine Resonance

The development of advanced millimeter-wave technology has made it possible to construct low-noise receivers and high-power transmitters comparable to those available at much lower frequencies. This technology, plus certain physical characteristics of the millimeter-wave spectrum, suggests possible advantages for use of this wavelength range for interstellar communications. As a result, a Search for ExtraTerrestrial Intelligence(SETI) type search has been conducted for narrow-bandwidth signals at frequencies near the positronium hyperfine spectral line (203.385 GHz), a potential natural reference frequency. A total of 40 solar-type stars within 23 parsecs were observed, in addition to three locations near the galactic center. No detections were made at the detection threshold of 2.3 x 10(exp -19) W/sq m in each of two orthogonal linear polarizations Future observations will be made with a higher resolution Fast Fourier Transform Spectrum Analyzer (FFTSA), which should improve sensitivity by an order of magnitude and reduce required observing time.

Steffes, Paul G.↗
NASA NTRS1982

A symbiotic approach to SETI observations: use of maps from the Westerbork Synthesis Radio Telescope

High spatial resolution continuum radio maps produced by the Westerbork Synthesis Radio Telescope (WSRT) of The Netherlands at frequencies near the 21 cm HI line have been examined for anomalous sources of emmission coincident with the locations of nearby bright stars. From a total of 542 stellar positions investigated, no candidates for radio stars or ETI signals were discovered to formal limits on the minimum detectable signal ranging from 7.7 x 10(-22) W/m2 to 6.4 x 10(-24) W/m2. This preliminary study has verified that data collected by radio astronomers at large synthesis arrays can profitably be analysed for SETI signals (in a non-interfering manner) provided only that the data are available in the form of a more or less standard two dimensional map format.

Exobiology/methods↗
NASA NTRS2018

New Assumptions to Guide SETI Research

The recent Kepler discoveries of Earth-like planets offer the opportunity to focus our attention on detecting signs of life and technology in specific planetary systems, but I feel we need to become more flexible in our assumptions. The reason is that, while it is still reasonable and conservative to assume that life is most likely to have originated in conditions similar to ours, the vast time differences in potential evolutions render the likelihood of "matching" technologies very slim. In light of these challenges I propose a more "aggressive" approach to future SETI exploration in directions that until now have received little consideration.

Colombano, S. P.↗
DOE OSTI2026

X-ray and γ-ray beam interstellar communication and implications for SETI

The possibility of detecting artificial signals transmitted by alien civilizations via collimated X-ray or gamma-ray beams is investigated. The prospect of using such beams for human communication within the solar system and beyond is also discussed. Detector responses were simulated for input signals and analyzed using relative entropy. For simplicity, all signals were assumed to use on-off keying (OOK) modulation. “Real” signals were generated by taking digital files and sequentially feeding their raw binary data to the detector simulator, the resulting normalized information content of the detector signals was plotted and compared to random noise signals. Since jpeg files contain compressed information, these served as a proxy for artificial alien signals. This showed that there is a clear difference in measured information content between natural and artificial signals, even with relatively poor time resolution in the detector causing the signals to be smeared (dead-time/rise-time intervals many times longer than the duration between signal pulses). It was found that so long as the signal lasts for at least several rise-time/dead-time intervals, the distinction between random and artificial signals is obvious. A space-telescope with high time resolution for searching for such signals is briefly described and its basic requirements are outlined.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Single-Electron Tracking (SETI)

We present the results of the first experiments on 6-dimensional phase-space tracking of a single electron in a storage ring, using a linear multi-anode photomultiplier tube for simultaneously measuring transverse coordinates and arrival times of synchrotron-radiation pulses. This technology makes it possible to fully reconstruct turn-by-turn positions and momentums in all three planes for a single particle. Complete experimental particle tracking enables the first direct measurements of dynamical properties, including invariants, tunes dependence on amplitudes with exceptional precision.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1976

Two systems analyses of SETI

The problem of receiving and identifying a single microwave signal transmitted by extraterrestrial intelligent beings is analyzed in the cases where the signal is designed to catch our attention and the signal is designed for internal purposes of another civilization. Six variables which yield uncertainty as to the exact signal which should be searched for are described: polarization, modulation, flux level, direction, frequency (including bandwidth and drift rate), and time. It is shown that if all reasonable variations of these parameters are to be examined sequentially for 1000 seconds, the search would take over a million times longer than the age of the Universe. Ways to simplify the search are considered, including widening the frequency bin, selecting specific targets, cutting the observation time, using a Fourier transform device for data processing, and building larger antennas as well as better low-noise receivers.

Machol, R. E.↗