Search NASA⌕ Search

SEARCH · Search NASA

Results for “Deep-Space”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Autonomy in space navigation

The potential development of autonomous onboard navigation systems for future space missions is discussed. Motivations for autonomy in the near-earth satellite program and in deep-space navigation are examined, emphasizing lower mission-operation costs for the first, and reduction of ground-system complexity as well as encounter accuracy for the latter. Uses of navigation parameters by the Information Adaptive System, including sensor-pointing computation and image correction, are noted, as are the accuracy parameters of the NAVSTAR Global Positioning System. The role of autonomous onboard navigation in contact exploration of Neptune's and Uranus's satellites as well as in such extreme-high-velocity encounters as those with retrograde comets is investigated. The Automated Optical Navigation program is described

Jordan, J. F.↗
NASA NTRS1978

Packet telemetry - A possible standard protocol for spacecraft data handling

Packetized telemetry-handling offers an opportunity to standardize major portions of the spacecraft-to-ground interface for future NASA missions. An end-to-end packet transport protocol is proposed which enables delivery of telemetry data from a remote space sensor to a ground-based user with virtually no project-unique intermediate processing. This paper reviews the possibility of creating a single telemetry format standard for both deep-space and near-earth missions. The proposed standard addresses the greatest NASA problem of the coming decade - cost - by allowing telemetry streams from many inflight spacecraft to be handled on the ground by common, simple, multimission processing elements.

Greenberg, E.↗
NASA NTRS1979

Detecting a gravitational-radiation background using spacecraft Doppler tracking

The sensitivity of NASA's Deep Space Network spacecraft tracking system to an isotropic cosmological background of gravitational radiation is analyzed. It is found that by using the autocovariance function of the Doppler record in the so-called 'three-way' tracking mode to dig into the noise it is possible to put significant limits on this background with current and future planned deep-space missions.

Hellings, R. W.↗
NASA NTRS1979

The JPL orbit determination software system

The Jet Propulsion Laboratory (JPL) orbit determination software system is described. Consisting of a set of computer programs, this system has been developed at JPL for the primary purpose of determining the flight path of deep-space mission spacecraft in NASA's planetary program. Secondary uses include science studies in celestial mechanics and extraterrestrial atmospherics. Attention is given to such features as the capability for processing 30 data types from up to 15 tracking stations, and for precise navigation to natural satellites of outer planets. In addition, the system contains models for such conditions as mascons, atmospheric drag, attitude control, and finite motor burns, to provide for extensive solve-on capabilities.

Ekelund, J. E.↗
NASA NTRS1981

Portable zero-delay assembly

Instrument is calibrated using back-to-back method. In comparison standard, S-X isolators are opposite from device being tested to permit signal flow in reverse direction. After calibration portable zero-delay assembly (PZDA) is used to set time delays of deep-space network ground-station ranging systems. Approach is also used to calibrate microwave links in other communications systems.

Franco, M. M.↗
NASA NTRS1980

The cosmic X-ray background

The cosmic X-ray experiment carried out with the A2 Instrument on HEAO-1 made systematics-free measurements of the extra-galactic X-ray sky and yielded the broadband spectral characteristics for two extreme aspects of this radiation. For the apparently isotropic radiation of cosmological origin that dominates the extragalactic X-ray flux ( 3 keV), the spectrum over the energy band of maximum intensity is remarkably well described by a thermal model with a temperature of a half-billion degrees. At the other extreme, broadband observations of individual extragalactic X-ray sources with HEAO-1 are restricted to objects within the present epoch. While the non-thermal hard spectral components associated with unevolved X-ray emitting active galaxies could account for most of the gamma-ray background, the contribution of such sources to the X-ray background must be relatively small. In contrast, the 'deep-space' sources detected in soft X-rays with the HEAO-2 telescope probably represent a major portion of the extragalactic soft X-ray ( 3 keV) background.

Boldt, E. A.↗
NASA NTRS1980

Shuttle Ku-band and S-band communications implementation study

Various aspects of the shuttle orbiter S-band network communication system, the S-band payload communication system, and the Ku-band communication system are considered. A method is proposed for obtaining more accurate S-band antenna patterns of the actual shuttle orbiter vehicle during flight because the preliminary antenna patterns using mock-ups are not realistic that they do not include the effects of additional appendages such as wings and tail structures. The Ku-band communication system is discussed especially the TDRS antenna pointing accuracy with respect to the orbiter and the modifications required and resulting performance characteristics of the convolutionally encoded high data rate return link to maintain bit synchronizer lock on the ground. The TDRS user constraints on data bit clock jitter and data asymmetry on unbalanced QPSK with noisy phase references are included. The S-band payload communication system study is outlined including the advantages and experimental results of a peak regulator design built and evaluated by Axiomatrix for the bent-pipe link versus the existing RMS-type regulator. The nominal sweep rate for the deep-space transponder of 250 Hz/s, and effects of phase noise on the performance of a communication system are analyzed.

Dodds, J. G.↗
NASA NTRS1980

Space Shuttle: Dawn of an era; Proceedings of the Twenty-sixth Annual Conference, Los Angeles, Calif., October 29-November 1, 1979. Parts 1 & 2

Aspects of the Space Shuttle program are considered with attention given to DOD applications, the role of the astronaut, industry in space, large platforms in space, the Space Transportation System, and the second generation Shuttle. Also considered are small self-contained payloads, attached payloads, free flying science payloads, free flying applications payloads, space medicine and life sciences, international payloads, and deep-space payloads.

Rector, W. F., III↗
NASA NTRS1980

Prospects for a breakthrough in field-dependent 'propulsion'

If sufficient justification exists to start the development of a field physics laboratory, attention might well be given to the development of two advanced types of field-independent propulsion systems. These are gravimagnetic systems and field resonance systems. The first are multipurpose propulsion systems employing the 'gravitational' effects of coherent electromagnetic energy configurations. The second are deep-space propulsion systems which artificially generate an energy pattern that matches precisely, or resonates with, a virtual pattern associated with a distant space-time point. A new model of space-time/field interactions is used in the present paper to describe the potential characteristics of electromagnetic/gravitational field interactions and the performance capabilities of these two propulsion systems.

Holt, A. C.↗
NASA NTRS1981

Microwave noise temperature and attenuation of clouds at frequencies below 50 GHz

The microwave attenuation and noise temperature effects of clouds can result in serious degradation of telecommunications link performance, especially for low-noise systems presently used in deep-space communications. Although cloud effects are generally less than rain effects, the frequent presence of clouds will cause some amount of link degradation a large portion of the time. Cloud types, water particle densities, radiative transfer, attenuation and noise temperature calculations are reviewed and examples of basic link signal to noise ratio calculations are given. Calculations for twelve different cloud models are presented for frequencies of from 1 to 50 GHz and elevation angles of 30 degrees and 90 degrees. These case results may be used as a handbook to predict noise temperature and attenuation values for known or forecast cloud conditions.

Slobin, S. D.↗
NASA NTRS1981

Deep space exploration - The new challenges

Prospects for future planetary exploration missions are examined. The evolution of planetary mission objectives in the U.S. and U.S.S.R. is traced, and planetary mission attempts and results are reviewed. The present situation with regard to planetary and interplanetary spacecraft operating in 1980 and approved deep-space missions for the future is considered, and the good scientific prospects of future Soviet missions are emphasized. Future plans for U.S. missions not yet approved are then discussed, with consideration given to the Venus Orbital Imaging Radar mission, a mission to Halley's comet, a rendezvous with a short-period comet, a Saturn orbiter mission with probes into Saturn and Titan, asteroid missions, gravity-assisted flights to Uranus, Neptune and Pluto, a Mercury orbiter/lander, lunar activities and a program of Mars exploration. The demanding requirements in the fields of automation, instrumentation and data gathering techniques, launch vehicle capabilities and spacecraft propulsion for future possible missions and possible solutions are examined. Finally, recommendations for the simultaneous pursuit of both major missions at the scientific and technological frontier and lesser missions designed to investigate specific scientific questions raised by earlier probes are presented.

French, J. R.↗
NASA NTRS1983

TRISCAN Antenna-Positioning Algorithm

TRISCAN scanning algorithm improves alinement between boresight of radar antenna and target. Algorithm originally developed for digitally pointed antennas in deep-space network; however, is possibly used in locating radio sources on Earth. TRISCAN estimates coordinate errors in hour angle and declination between predicted and true locations of radio source.

Bunce, R. C.↗
NASA NTRS1981

Goldstone (GDSCC) administrative computing

The GDSCC Data Processing Unit provides various administrative computing services for Goldstone. Those activities, including finance, manpower and station utilization, deep-space station scheduling and engineering change order (ECO) control are discussed.

Martin, H.↗
NASA NTRS1980

The effects of receiver tracking phase error on the performance of the concatenated Reed-Solomon Viterbi channel coding system

In connection with attempts to achieve very low error probabilities, Odenwalder (1970) proposed a concatenated coding system using the Viterbi-decoded convolutional codes as the inner code and Reed-Solomon (RS) codes as the outer code. Analytical and experimental results are presented concerning the effects of the receiver tracking phase error on the performance of the concatenated RS/Viterbi channel coding system. On the basis of these results it is concluded that certain problems regarding communication operations on deep-space missions can be alleviated by employing the RS/Viterbi coding system. In one-way communication, an employment of RS/Viterbi coding will also provide greater data protection than the Viterbi-decoded convolutional-only coding system.

Liu, K. Y.↗
NASA NTRS1983

Nutation Damper System

The Nutation Damper System is a three function mechanism designed for the Galileo Spacecraft, a spin stabilized deep-space probe to Jupiter. By damping the movement of a large deployable science boom acting as an outboard pendulum, the nutation damper rapidly stabilizes the spacecraft from dynamic irregularities. The system includes the boom deployment device and the ultra-low friction boom hinge. This paper describes the mechanism, the degree to which friction, stiction and lost motion have been eliminated, and the unique test methods that allow its performance to be measured.

Sevilla, D. R.↗
NASA NTRS1983

Antennas

Reception of the exceedingly small signals from spacecraft typical of deep space communication requires antennas of enormous size, complexity, and precision. The two Voyager spacecraft each have 20-watt X-band transmitters; and at their Saturn encounter distances from Earth of approximately 1.5 billion kilometers, the power density received on the Earth was less than 10 to the minus 19th power watts per square meters. The thrust in deep-space communications improvement was in the areas of ground and spacecraft antenna size and performance increases, spacecraft transmitter power increase, ground receiving system design, and telemetry information coding. Ground antenna theory, design, and performance as related to the particular problem of receiving spacecraft signals using the Deep Space Network (DSN) is described.

Slobin, S. D.↗
NASA NTRS1982

Microwave noise temperature and attenuation of clouds - Statistics of these effects at various sites in the United States, Alaska, and Hawaii

The microwave attenuation and noise temperature effects of clouds can result in serious degradation of telecommunications link performance, especially for low-noise systems presently used in deep-space communications. Although cloud effects are generally less than rain effects, the frequent presence of clouds will cause some amount of link degradation a large portion of the time. This paper presents a general review of cloud types and their water particle densities, attenuation and noise temperature calculations, and basic link signal-to-noise ratio calculations. Tabular results of calculations for 12 different cloud models are presented for frequencies in the range 10-50 GHz. Curves of average-year attenuation and noise temperature statistics at frequencies ranging from 10 to 90 GHz, calculated from actual surface and radiosonde observations, are given for 15 climatologically distinct regions in the contiguous United States, Alaska, and Hawaii. Nonuniform sky cover is considered in these calculations.

Slobin, S. D.↗
NASA NTRS1983

Mariner Mark II and the exploration of the solar system

NASA's Solar System Exploration Committee has proposed the Mariner Mark II concept for the next generation of deep-space planetary observation missions, which will yield Voyager- and Galileo-quality focused data sets at a fraction of the costs associated with those spacecraft. Cost-limiting strategies under consideration include the use of reconfigurable designs, a multimission ground support system, and the incorporation of such selected new technologies as an all-X band telemetry system, fiber-optic rate sensors for use as an inertial reference system, image compression, and electronic and optical disk data distribution. It is believed possible to meet cost goals of 150-300 million/mission. The missions under consideration are comet rendezvous and sample return, main belt asteroid flybys, and orbits, flybys and probes of Saturn, Titan, Neptune and Uranus.

Neugebauer, M.↗