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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 NTRS1994

A database for propagation models

A database of various propagation phenomena models that can be used by telecommunications systems engineers to obtain parameter values for systems design is presented. This is an easy-to-use tool and is currently available for either a PC using Excel software under Windows environment or a Macintosh using Excel software for Macintosh. All the steps necessary to use the software are easy and many times self-explanatory; however, a sample run of the CCIR rain attenuation model is presented.

Kantak, Anil V.↗
NASA NTRS1995

A database for propagation models

A database of various propagation phenomena models that can be used by telecommunications systems engineers to obtain parameter values for systems design is presented. This is an easy-to-use tool and is currently available for either a PC using Excel software under Windows environment or a Macintosh using Excel software for Macintosh. All the steps necessary to use the software are easy and many times self explanatory.

Kantak, Anil V.↗
NASA NTRS1998

Propagation Models Database

A database of various propagation phenomena models which can be used by the telecommunications systems engineers to obtain the desired parameter values for systems design.

communication satellites radio waves wave propagat↗
NASA NTRS1995

The International GPS Network for Charting the Evolving Global Reference Frame

The Telecommunications and Engineering Division of Caltech's Jet Propulsion Laboratory is funded by the National Aeronautics and Space Administration to play a variety of roles in applying the Global Positioning System (GPS) to geodesy and geodynamics. Among these are the operation of dozens of globally-distributed, permanently-operating Earth fixed GPS stations. This, and other applications are described.

Geodynamics Geodesy Global Positioning System GPS↗
NASA NTRS2007

Jet Propulsion Laboratory: Annual Report 2006

Nothing is as gratifying in space exploration as when we are surprised by the unexpected. Much of our work progresses in an orderly way, from concept to plan to creation to finding. But now and then we are caught off-guard by something startlingly new, and it is these moments that make our hearts race and leave us with many of our most compelling memories. And 2006 was an exceptional year for the unforeseen. One of our orbiters shocked many with stark proof that liquid water, the seemingly long-gone force that reshaped so much of the scenery of Mars, still flows there today,at least in occasional bursts. Another spacecraft caught us by surprise with photos of Yellowstone-like geysers on one of Saturn's seemingly nondescript moons, Enceladus. A spaceborne observatory created to plumb the life histories of stars and galaxies showed off a completely unexpected talent when it revealed the day and night faces of a fire and ice planet far beyond our solar system 40 light-years away. A newly launched Earth observer revealed that the clouds that decorate our own planet are not what we thought them to be in many ways. Of course, not all of the high points of the year arrived on our doorstep in such unexpected ways. There was also great drama when missions came off exactly as planned, such as when Stardust's sample return capsule made a flawless landing in the Utah desert, bringing home samples of cometary and interstellar dust. Mars Reconnaissance Orbiter slipped into orbit around the red planet exactly as planned. Numerous other missions and technology programs likewise made great achievements during the year. In all, 17 spacecraft and six instruments were stationed across the solar system, studying our own world, other planets, comets and the deeper universe. All of these achievements were enabled by many teams and systems at the Laboratory. The Deep Space Network of communications complexes across three continents supported all of NASA's solar system missions, and several from our international partners, while looking ahead to reinvent itself for the future. Technologists were at work creating innovations both for NASA missions and terrestrial uses. JPL's community of scientific researchers was equally busy coordinating the science activities of our missions and pursuing independent investigations. None of this would be possible without the support of business and administrative teams dedicated to making the Laboratory's institutional environment as world-class as its technical face, or the public engagement specialists who bring the experience of space to the country's diverse publics. All of our missions in one way or another support our nation's Vision for Space Exploration, which envisages a gradually widening robotic and human presence across the solar system in the years ahead.

National Aeronautics and Space Administration (NAS↗
NASA NTRS2009

Jet Propulsion Laboratory: Annual Report 2008

Nothing is more exciting than when science mines the far end of our knowledge for the new and the unexpected. In 2008, the world was taken by surprise when JPL astronomers announced the discovery of organic compounds on a planet orbiting another star. We were equally excited to learn from the Spitzer Space Telescope that many, if not most, sun-like stars have rocky planets roughly similar to Earth. Together these are very intriguing clues in our quest to learn if there is life elsewhere in the universe, which certainly has to be one of the most profound mysteries of our age.There are times when, dealing with unknowns, we are reminded to be humble. Very impressive progress is being made by the team developing our next flagship mission, Mars Science Laboratory. Ther conclusion, however, is that it would not be safe to try to fly during the Mars launch window in 2009, and reset for the next opportunity in 2011. We are lucky to have valuable assets that support us as we venture into the unknown. One is the global Deep Space Network, which functions both as our communication gateway to our spacecraft across the solar system as well as a research tool itself in conducting radar astronomy. Our successes depend on our entire team, administrators and business specialists as much as technical people. There are those who help share our missions with the public, finding imaginative venues such as sending out dispatches on the Internet's Twitter.com during the Phoenix mission. We also benefit greatly from the intellectual infusion that comes from our unique identity as a division of the California Institute of Technology and a member of the NASA family.

National Aeronautics and Space Administration (NAS↗
NASA NTRS1983

Telemetry Modulation and Coping

Digital telemetry has supplanted analog telemetry for deep space communications. With digital telemetry, the telecommunications systems design engineer may use error correcting codes. This allows increased error protection at the cost of increased bandwidth. All science telemetry returned from the Voyager and Galileo spacecraft are protected by error correcting codes. Both the modulation and coding of digital telemetry for the deep space channel are considered. The descriptions include relative performance of some competing schemes. However, the treatment given here is, of necessity, cursory. A small class of modulation schemes has proven to be best for the deep space channel. The digital telemetry is either phase-shift-keyed onto a squarewave subcarrier and then phase modulated onto the carrier or the digital telemetry is directly phase modulated onto the carrier.

Kinman, P. W.↗
NASA NTRS1984

Resident research associateships. Postdoctoral and senior research awards: Opportunities for research at the Jet Propulsion Laboratory

Opportunities for research as part of NASA-sponsored programs at the JPL cover: Earth and space sciences; systems; telecommunications science and engineering; control and energy conversion; applied mechanics; information systems; and observational systems. General information on applying for an award for tenure as a guest investigator, conditions, of the award, and details of the application procedure are provided.

Source record↗
NASA NTRS1996

A Database for Propagation Models and Conversion to C++ Programming Language

The telecommunications system design engineer generally needs the quantification of effects of the propagation medium (definition of the propagation channel) to design an optimal communications system. To obtain the definition of the channel, the systems engineer generally has a few choices. A search of the relevant publications such as the IEEE Transactions, CCIR's, NASA propagation handbook, etc., may be conducted to find the desired channel values. This method may need excessive amounts of time and effort on the systems engineer's part and there is a possibility that the search may not even yield the needed results. To help the researcher and the systems engineers, it was recommended by the conference participants of NASA Propagation Experimenters (NAPEX) XV (London, Ontario, Canada, June 28 and 29, 1991) that a software should be produced that would contain propagation models and the necessary prediction methods of most propagation phenomena. Moreover, the software should be flexible enough for the user to make slight changes to the models without expending a substantial effort in programming. In the past few years, a software was produced to fit these requirements as best as could be done. The software was distributed to all NAPEX participants for evaluation and use, the participant reactions, suggestions etc., were gathered and were used to improve the subsequent releases of the software. The existing database program is in the Microsoft Excel application software and works fine within the guidelines of that environment, however, recently there have been some questions about the robustness and survivability of the Excel software in the ever changing (hopefully improving) world of software packages.

Kantak, Anil V.↗
NASA NTRS2000

Planning and Processing Space Science Observations Using NASA's SPICE System

The Navigation and Ancillary Information Facility (NAIF) team, acting under the directions of NASA's Office of Space Science, has built a data system-named SPICE, to assist scientists in planning and interpreting scientific observations from space-borne instruments. The principal objective of this data system is that it will provide geometric and other ancillary data used to plan space science missions and subsequently recover the full value of science instrument data returned from these missions, including correlation of individual instrument data sets with data from other instruments on the same or other spacecraft. SPICE is also used to support a host of mission engineering functions, such as telecommunications system analysis and operation of NASA's Deep Space Network antennas. This paper describes the SPICE system, including where and how it is used. It also touches on possibilities for further development and invites participation it this endeavor.

Acton, Charles H.↗
NASA NTRS2002

Radio Wave Propagation Handbook for Communication on and Around Mars

This handbook examines the effects of the Martian environment on radio wave propagation on Mars and in the space near the planet. The environmental effects include these from the Martian atmosphere, ionosphere, global dust storms, aerosols, clouds, and geomorphologic features. Relevant Martian environmental parameters were extracted from the measurements of Mars missions during the past 30 years, especially from Mars Pathfinder and Mars Global Surveyor. The results derived from measurements and analyses have been reviewed through an extensive literature search. The updated parameters have been theoretically analyzed to study their effects on radio propagation. This handbook also provides basic information about the entire telecommunications environment on and around Mars for propagation researchers, system engineers, and link analysts. Based on these original analyses, some important recommendations have been made, including the use of the Martian ionosphere as a reflector for Mars global or trans-horizon communication between future Martian colonies, reducing dust storm scattering effects, etc. These results have extended our wave propagation knowledge to a planet other than Earth; and the tables, models, and graphics included in this handbook will benefit telecommunication system engineers and scientific researchers.

Ho, Christian↗