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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

An evaluation of Galileo-Viking differenced range in Galileo-Mars flyby navigation

A summary and evaluation of the Galileo-Mars flyby navigation techniques is presented. The navigational requirements of Galileo as it swings by Mars are going to be met with interferometric angular measurements (VLBI) and range and range-rate measurements. Like VLBI, dual spacecraft differenced range is less sensitive to Mars ephemeris errors and tracking station location errors than conventional range and Doppler. Similarly, differenced range provides angular information about the separation between the Mars Viking Lander I and the Galileo spacecraft. In covariance studies, dual spacecraft range coupled with conventional range and Doppler is shown to estimate the Galileo-Mars flyby distance to better than 10 km which is comparable to the VLBI performance. For the Galileo-Mars flyby, dual spacecraft differenced range promise to be an excellent backup to VLBI if the Mars Viking Lander remains operational.

Winn, F. B.↗
NASA NTRS1994

Tracking the Galileo spacecraft with the DSCC Galileo Telemetry prototype

On day of the year 062, 1994, a prototype of the Deep Space Communications Complex Galileo Telemetry subsystem successfully tracked and processed signals from the Galileo spacecraft, under fully suppressed-carrier modulation. The demonstration took place at Goldstone, employing the 70-m antenna and the 34-m high-efficiency antenna. This article presents the findings from that demonstration. Specific issues are the system performance in terms of signal-to-noise (SNR) degradation and the arraying gain. Validation of the test results is via symbol-error-rate measurement and the standard symbol SNR. The analysis is also extended to include characterization of the signal received from Galileo.

Pham, T. T.↗
NASA NTRS1989

STS-34 Galileo PCR at Pad & Galileo in Atlantis

The primary objective of the STS-34 mission was the deployment of the Galileo spacecraft and the attached Inertial Upper Stage. This videotape shows the Galileo in the Payload Clean Room in preparation for the six year trip to Jupiter. There are also views of the spacecraft in the Atlantis Payload Bay.

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NASA NTRS1988

Galileo probe parachute test program: Wake properties of the Galileo probe at Mach numbers from 0.25 to 0.95

The results of surveys of the near and far wake of the Galileo Probe are presented for Mach numbers from 0.25 tp 0.95. The trends in the data resulting from changes in Mach number, radial and axial distance, angle of attack, and a small change in model shape are shown in crossplots based on the data. A rationale for selecting an operating volume suitable for parachute inflation based on low Mach number flight results is outlined.

Canning, Thomas N.↗
NASA NTRS1992

Galileo Earth/Moon News Conference

This NASA Kennedy Space Center (KSC) video release (Part 1 of 2) begins with a presentation given by William J. O'Neil (Galileo Project Manager) describing the status and position of the Galileo spacecraft 7 days prior to the Galileo Earth-2 flyby. Slides are presented including diagrams of the Galileo spacecraft trajectory, trajectory correction maneuvers, and the Venus and asteroid flybys. Torrence Johnson (Galileo Project Scientist) follows Mr. O'Neil with an explanation of the Earth/Moon science activities that will be undertaken during the second Galileo/Earth encounter. These activities include remote sensing, magnetospheric and plasma measurements, and images taken directly from Galileo of the Earth and Moon. Dr. Joseph Veverka (Galileo Imaging Team, Cornell University) then gives a brief presentation of the data collected by the first Galileo/Gaspra asteroid flyby. Images sampled from the 57 photographs taken of Gaspra are presented along with discussions of Gaspra's morphology, shape and size, and surface features. These presentations are followed by a question and answer period given for the benefit of scientific journalists whose subjects include overall Galileo spacecraft health, verification of the Gaspra images timeframe, and the condition of certain scientific spacecraft instruments. Part 2 of this video can be retrieved by using Report No. NONP-NASA-VT-2000001078.

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NASA NTRS1989

Galileo Mission Science Briefing

The first of two tapes of the Galileo Mission Science press briefing is presented. The panel is moderated by George Diller from the Kennedy Space Center (KSC) Public Affairs Office. The participants are John Conway, the director of Payload and operations at Kennedy; Donald E. Williams, Commander of STS-43, the shuttle mission which will launch the Galileo mission; John Casani, the Deputy Assistant Director of Flight Projects at the Jet Propulsion Lab (JPL); Dick Spehalski, Galileo Project Manager at JPL; and Terrence Johnson, Galileo Project Scientist at JPL. The briefing begins with an announcement of the arrival of the Galileo Orbiter at KSC. The required steps prior to the launch are discussed. The mission trajectory and gravity assists from planetary and solar flybys are reviewed. Detailed designs of the orbiter are shown. The distance that Galileo will travel from the sun precludes the use of solar energy for heat. Therefore Radioisotope heater units are used to keep the equipment at operational temperature. A video of the arrival of the spacecraft at KSC and final tests and preparations is shown. Some of the many science goals of the mission are reviewed. Another video showing an overview of the Galileo mission is presented. During the question and answer period, the issue of the use of plutonium on the mission is broached, which engenders a review of the testing methods used to ensure the safety of the capsules containing the hazardous substance. This video has actual shots of the orbiter, as it is undergoing the final preparations and tests for the mission.

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NASA NTRS1997

Galileo Science Update

Live footage shows Jane Platt, JPL Public Information Office, introducing the moderator of the panel discussion. The moderator introduces the panel members include Bill O'Neil, Project Manager Galileo Primary Mission, Dr. Torrence V. Johnson Galileo Project Scientist, Prof. Ronald Greeley from Arizona State University Galileo Imaging Team, Bob Mitchell Project Manager Galileo Europa Mission, and Dr. Karen Buxbaum Galileo Science Planning Manager. The panelists give the audience information about the Galileo Mission and answers questions from the audience and from Kennedy Space Center. An animation of the Galileo Spacecraft approaching and passing Europa is presented. The panelists mentions High Resolution Images, Detail Gravity studies, Spectral Maps of non-ice materials, Jupiter studies, Callisto studies, Europa studies, and Io studies.

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NASA NTRS1988

A new code for Galileo

Over the past six to eight years, an extensive research effort was conducted to investigate advanced coding techniques which promised to yield more coding gain than is available with current NASA standard codes. The delay in Galileo's launch due to the temporary suspension of the shuttle program provided the Galileo project with an opportunity to evaluate the possibility of including some version of the advanced codes as a mission enhancement option. A study was initiated last summer to determine if substantial coding gain was feasible for Galileo and, is so, to recommend a suitable experimental code for use as a switchable alternative to the current NASA-standard code. The Galileo experimental code study resulted in the selection of a code with constant length 15 and rate 1/4. The code parameters were chosen to optimize performance within cost and risk constraints consistent with retrofitting the new code into the existing Galileo system design and launch schedule. The particular code was recommended after a very limited search among good codes with the chosen parameters. It will theoretically yield about 1.5 dB enhancement under idealizing assumptions relative to the current NASA-standard code at Galileo's desired bit error rates. This ideal predicted gain includes enough cushion to meet the project's target of at least 1 dB enhancement under real, non-ideal conditions.

Dolinar, S.↗
NASA NTRS1990

Project Galileo

Galileo is now enroute to Jupiter to do its intensive and comprehensive investigation of the Jupiter System. The Galileo Spacecraft consists of a Jupiter Orbiter and an Atmospheric Entry Probe. The Galileo mission at Jupiter is described. The design and operation of the Probe and Orbiter are discussed in some detail. The history of the many Shuttle upper stage changes Galileo experienced during development is outlined. The VEEGA trajectory Galileo is flying to achieve enough energy to reach Jupiter is explained. Science of opportunity on the circuitous VEEGA route is identified. Galileo Mission Operations are described. The paper concludes with an inflight mission status statement.

O'Neil, William J.↗
NASA NTRS1992

Galileo Press Conference from JPL

This two-tape Jet Propulsion Laboratory (JPL) video production presents a Dec. 8, 1992 press conference held at JPL to discuss the final Galileo spacecraft encounter with Earth before beginning its journey to Jupiter. The main theme of the conference was centered on the significance of the 2nd and final Earth/Moon flyby as being the spacecraft's last planetary encounter in the solar system before reaching Jupiter, as well as final flight preparations prior to its final journey. Each person of the five member panel was introduced by Robert MacMillan (JPL Public Information Mgr.) before giving brief presentations including slides and viewgraphs covering their area of expertise regarding Galileo's current status and future plans. After the presentations, the media was given an opportunity to ask questions of the panel regarding the mission. Mr. Wesley Huntress (Dir. of Solar System Exploration (NASA)), William J. ONeill (Galileo Project Manager), Neal E. Ausman, Jr. (Galileo Mission Director), Dr. Torrence V. Johnson (Galileo Project Scientist) and Dr. Ronald Greeley (Member, Imaging Team, Colorado St. Univ.) made up the panel and discussed topics including: Galileo's interplanetary trajectory; project status and performance review; instrument calibration activities; mission timelines; lunar observation and imaging; and general lunar science. Also included in the last three minutes of the video are simulations and images of the 2nd Galileo/Moon encounter.

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NASA NTRS2001

Understanding of Jupiter's Atmosphere After the Galileo Probe Entry

Instruments on the Galileo probe measured composition, cloud properties, thermal structure. winds, radiative energy balance, and electrical properties of the Jovian atmosphere. As expected the probe results confirm some expectations about Jupiter's atmosphere, refute others, and raise new questions which still remain unanswered. This talk will concentrate on those aspects of the probe observations which either raised new questions or remain unresolved. The Galileo probe observations of composition and clouds provided some of the biggest surprises of the mission. Helium abundance measured by the probe differed significantly from the remote sensing derivations from Voyager. discrepancy between the Voyager helium abundance determinations for Jupiter and the Galileo probe value have now led to a considerably increased helium determination for Saturn. Global abundance of N in the form of ammonia was observed to be supersolar by approximately the same factor as carbon, in contrast to expectations that C/N would be significantly larger than solar. This has implications for the formation and evolution of Jupiter. The cloud structure was not what was generally anticipated, even though most previous remote sensing results below the uppermost cloud referred to 5 micron hot spots, local regions with reduced cloud opacity. The Galileo probe descended in one of these hot spots. Only a tenuous, presumed ammonium hydrosulfide, cloud was detected, and no significant water cloud or super-solar water abundance was measured. The mixing ratios as a function of depth for the condensibles ammonia, hydrogen sulfide, and water, exhibited no apparent correlation with either condensation levels or with each other, an observation that is still a puzzle, although there are now dynamical models of hot spots which show promise in being able to explain such behavior. Probe tracked zonal winds show that wind magnitude increases with depth to pressures of about 4 bars, with the winds extending to at least as deep as the probe made measurements, 22 bars. Models of hot spot dynamics raise the possibility that the variation with depth of the probe measured zonal winds between 0.4 and 4 bars reflect the dynamics of the hot spot rather than the global wind pattern. Galileo upper atmosphere measurements established that there is a sharp temperature rise with altitude between about 350 and 800 km above the 1 bar pressure level, with the upper atmosphere reaching, temperatures near 900 K. The energy sources for this upper atmosphere heating are not clearly established, but various mechanisms have been proposed. These and other aspects of the Galileo probe data will be discussed.

Young, Richard E.↗
NASA NTRS2003

Understanding of Jupiter's Atmosphere after the Galileo Probe Entry

Instruments on the Galileo probe measured composition, cloud properties, thermal structure, winds, radiative energy balance, and electrical properties of the Jovian atmosphere. As expected the probe results confirm some expectations about Jupiter's atmosphere, refute others, and raise new questions which still remain unanswered. This talk will concentrate on those aspects of the probe observations which either raised new questions or remain unresolved. The Galileo probe observations of composition and clouds provided some of the biggest surprises of the mission. Helium abundance measured by the probe differed significantly from the remote sensing derivations from Voyager. Discrepancy between the Voyager helium abundance determinations for Jupiter and the Galileo probe value have now led to a considerably increased helium determination for Saturn. Global abundance of N in the form of ammonia was observed to be super-solar by approximately the same factor as carbon, in contrast to expectations that C/N would be significantly larger than solar. This has implications for the formation and evolution of Jupiter. The cloud structure was not what was generally anticipated, even though most previous remote sensing results below the uppermost cloud referred to 5 micron hot spots, local regions with reduced cloud opacity. The Galileo probe descended in one of these hot spots. Only a tenuous, presumed ammomium hydrosulfide, cloud was detected, and no significant water cloud or super-solar water abundance was measured. The mixing ratios as a function of depth for the condensibles ammonia, hydrogen sulfide, and water, exhibited no apparent correlation with either condensation levels or with each other, an observation that is still a puzzle, although there are now dynamical models of hot spots which show promise in being able to explain such behavior. Probe tracked zonal winds show that wind magnitude increases with depth to pressures of about 4 bars, with the winds extending to at least as deep as the probe made measurements, 22 bars. Models of hot spot dynamics raise the possibility that the variation with depth of the probe measured zonal winds between 0.4 and 4 bars reflect the dynamics of the hot spot rather than the global wind pattern. Galileo upper atmosphere measurements established that there is a sharp temperature rise with altitude between about 350 and 800 km above the 1 bar pressure level, with the upper atmosphere reaching temperatures near 900 K. The energy sources for this upper atmosphere heating are not clearly established, but various mechanisms have been proposed. These and other aspects of the Galileo probe data will be discussed.

Fonda, Mark↗
NASA NTRS1997

(abstract) Final Galileo Propulsion System In-Flight Characterization (Extended Abstract)

The Galileo Retropropulsion Module (RPM) has performed excellently during nearly seven years of Galileo mission operations. The RPM was provided by the Federal Republic of Germany to NASA to provide directed impulse to the Galileo spacecraft during all phases of the Galileo mission following Inertial Upper Stage (IUS) jettison. This paper documents the in-flight performance of the Galileo propulsion system since July 1993.

Galileo Galileo Retropropulsion Module propellants↗
NASA NTRS1982

The Galileo Delta-VEGA mission to Jupiter

Project Galileo is to perform a more comprehensive investigation of the Jupiter system than was possible with Voyager. The Galileo spacecraft consists of both a planetary Orbiter and an atmospheric entry Probe. In connection with budgetary considerations and schedule problems, plans concerning the implementation of the project were changed a number of times. For the first seven months of 1982, the project Galileo was baselined as a Delta-VEGA transfer to be launched in 1985 by the Space Shuttle using the U.S. Air Force two-stage IUS as the upper stage augmented by a spacecraft Injection Module. The new mission and systems aspects of this 1985 Galileo Delta-VEGA baseline are compared to the prior 1985 Centaur direct transfer baseline. The techniques developed to virtually restore all the mission science in spite of greatly reduced launch vehicle performance are discussed. In July 1982, the U.S. Government reinstated the Centaur development and stipulated that Galileo be launched by Shuttle/Centaur in 1986.

Oneil, W. J.↗
NASA NTRS1985

Galileo

The Galileo consists of two main parts: a Jupiter orbiter and a probe. After a 1000 day journey, the Galileo will assume orbit around the giant planet, an orbit which will last for 200 days, in the hopes of astronomers. The orbit will carry the Galileo past its four Jovian satellites--Io, Europa, Ganymede, and Callisto - a combined total of 11 times. This will enable scientists to study the atmosphere of not only the largest planet in the solar system, but its large moons as well. Sometime in August of 1988, the Galileo will approach Jupiter and begin its important activities. Fifty-six days away from planetary encounter, the Galileo will release the probe which will continue the trip to Jupiter and enter the atmosphere. As it descends through the atmosphere, the probe will unfurl a parachute to slow its speed as it broadcasts information back to the waiting orbiter, which will in turn relay it back to the waiting scientists on Earth. The probe's descent time is expected to be approximately 15 min before Jupiter's pressure and heat overwhelm the probe's protection. However, scientists are hopeful that the probe will survive longer than 15 min, possibly up to 60 min.

Hwang, C.↗
NASA NTRS1995

Analysis of Gaspra lightcurves using Galileo shape and photometric models

Galileo-based models for the shape of 951 Gaspra and the global-average photometric behavior of its surface have been used to model a representative subset of the asteroid's telescopic lightcurves. Fitting the synthetic lightcurves to the observed timing of lightcurve extrema, and knowing the orientation of Gaspra's axes at the time of the Galileo flyby, leads to a sidereal rotation period for the asteroid of 7.042024 +/- 0.000020 hr, a slight change from the period reported by Magnusson et al. (1992). Initially, the shapes, amplitudes, and absolute photometry of the synthetic and observed lightcurves agree with each other to within 0.05-0.1 mag. Small modifications to the Gaspra shape model on sides of the asteroid poorly imaged by Galileo (changes of 700 m or less in the southern hemisphere at longitudes 90 deg-270 deg W) reduce the typical discrepancies to approximately 0.05 mag in lightcurve shape and less than 0.03 mag in absolute photometry. The result demonstrates that Earth-based lightcurves can be used to refine the shape of a spacecraft-imaged irregular object in areas that are poorly constrained by the spacecraft observations. The consistency and phase-angle dependence of the Galileo-based model for Gaspra photometry, supports the accuracy of the absolute calibration of the Galileo SSI camera, and confirms the Earth-based determination of the V-filter geometric albedo of the asteroid (0.22 +/- 0.03; Tholen et al., submitted for publication). Remaining discrepancies between the synthetic and observed lightcurves show no indication of systematic latitudinal variations in albedo and also cannot be explained entirely by isolated albedo spots. These discrepancies are most likely caused by (1) small, remaining, hard-to-constrain errors in the Gaspra shape model and/or (2) moderate variations in macroscopic roughness across the asteroid's surface, in particular making longitudes 130 deg to 300 deg W moderately rougher than the opposite hemisphere.

Simonelli, Damon P.↗
NASA NTRS1997

(abstract) Galileo Navigation: Launch to Jupiter Orbit

The Galileo spacecraft was launched on October 18, 1989. After a 3.7 billion kilometer journey lasting just over six years, the Galileo Orbiter and Probe arrived at Jupiter on December 7, 1995. The atmospheric Probe survived its atmospheric entry and successfully transmitted data to the Orbiter flying overhead. To date, the Orbiter has successfully completed the first three of the ten planned satellite encounters. Navigation for the Galileo Mission has proved to be a unique and challenging task. The challenges and results of navigating Galileo through the interplanetary transfer to Jupiter, delivery of the atmospheric entry Probe, Jupiter orbit insertion, and the orbital tour are presented in this paper.

Galileo Jupiter navigation orbits gravity assists ↗