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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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NASA NTRS2017

Overview of SPRITE: Saturn Probe Interior and aTmosphere Explorer Concept

The Saturn PRobe Interior and aTmosphere Explorer (SPRITE) mission concept targets high-priority Planetary Science Decadal Survey science objectives. This mission concept would deliver the SPRITE entry probe into the Saturn atmosphere to obtain in situ measurements of elemental abundances and isotopic ratios, which would help distinguish the role Saturn played in the solar system formation and co-evolution of other planets. An Atmospheric Structure Investigation sensor package on the entry probe would provide in situ measurements of the pressure/temperature and wind structure below the cloud-tops, and a Quadrupole Mass Spectrometer and Tunable Laser Spectrometer suite would determine the composition of Saturn’s atmosphere. The SPRITE mission concept described in this paper uses a solar-powered carrier-relay spacecraft to deliver the battery-powered entry probe to Saturn after a 10-year Venus-Earth-Earth gravity-assist trajectory, and then relays the probe data back to Earth during the carrier-relay spacecraft Saturn flyby. A high-heritage design approach is implemented for the flight elements to minimize technical risk and enable successful return of this high-value science data.

Cuddy, Cavan↗
NASA NTRS1995

A Systems Engineering Approach to the Analysis of a Planetary Mission Ground System in Terms of Science Objectives

The most fundamental objective of all planetary missions is to return data. To accomplish this, a spacecraft is fabricated and built, software is planned and coded, and a ground system is designed and implemented. However, a systems engineering approach to determine how the collection of data drives ground system capabilities has received little attention.This paper defines a technique by which science objectives can be quantitatively evaluated. For illustrative purposes, it will be applied to NASA's Cassini Mission. This mission, to be launched in 1997, is an international endeavor designed to orbit Saturn for four years.The results of this systems engineering approach will show which science objectives drive specific ground system capabilities. In addition, this technique can assist system engineers in the selection of the science payload during pre-project mission planning; ground system designers during ground system development and implementation; and operations personnel during the mission.

systems engineering, ground systems↗
NASA NTRS1988

Bombardment history of the Saturn system

Crater distributions on Voyager images of Saturn's satellites are analyzed and models of relative cratering rates on these bodies are developed on the basis of orbital dynamics. A history of satellite bombardment, disruption, and resurfacing in the Saturn system is constructed, concentrating on Rhea. It is suggested that the surface of Rhea has approached saturation equilibrium for craters with diameters up to 32 km. Also, the disruption probabilities of Saturn's inner moons are estimated.

Lissauer, Jack J.↗
NASA NTRS1991

Goldstone Solar System Radar (GSSR)

The primary objective of the Goldstone Solar System Radar is the investigation of solar system bodies by means of Earth-based radar. Targets of primary interest include the Galilean moons, Saturn's rings and moons, and Earth-approaching asteroids and comets. Planets are also of interest, particularly Mercury and the planets to which NASA has not yet planned spacecraft visits. Based on a history of solid achievement, including the definition of the Astronomical Unit, imaging and topography of Mars, Venus, and Mercury, and contributions to the general theory of relativity, the program will continue to support flight project requirements and its primary objectives. The individual target objectives are presented, and information on the following topics are presented in tabular form: Deep Space Network support, compatibility tests, telemetry, command, and tracking support responsibility.

Renzetti, N. A.↗
NASA NTRS2005

Low-Cost Innovation in Spaceflight: The Near Earth Asteroid Rendezvous (NEAR) Shoemaker Mission

On a spring day in 1996, at their research center in the Maryland countryside, representatives from the Johns Hopkins University Applied Physics Laboratory (APL) presented Administrator Daniel S. Goldin of the National Aeronautics and Space Administration (NASA) with a check for $3.6 million. 1 Two and a half years earlier, APL officials had agreed to develop a spacecraft capable of conducting an asteroid rendezvous and to do so for slightly more than $122 million. This was a remarkably low sum for a spacecraft due to conduct a planetaryclass mission. By contrast, the Mars Observer spacecraft launched in 1992 for an orbital rendezvous with the red planet had cost $479 million to develop, while the upcoming Cassini mission to Saturn required a spacecraft whose total cost was approaching $1.4 billion. In an Agency accustomed to cost overruns on major missions, the promise to build a planetary-class spacecraft for about $100 million seemed excessively optimistic.

McCurdy, Howard E.↗
NASA NTRS2005

Preliminary Assessment of Thrust Augmentation of NEP Based Missions

Science Applications International Corporation (SAIC), with support from NASA Marshall Space Flight Center, has conducted a preliminary study to compare options for augmenting the thrust of a conventional nuclear electric propulsion (NEP) system. These options include a novel nuclear propulsion system concept known as Hybrid Indirect Nuclear Propulsion (HINP) and conventional chemical propulsion. The utility and technical feasibility of the HINP concept are assessed, and features and potential of this new in-space propulsion system concept are identified. As part of the study, SAIC developed top-level design tools to model the size and performance of an HINP system, as well as for several chemical propulsion options, including liquid and gelled propellants. A mission trade study was performed to compare a representative HINP system with chemical propulsion options for thrust augmentation of NEP systems for a mission to Saturn's moon Titan. Details pertaining to the approach, features, initial demonstration results for HINP model development, and the mission trade study are presented. Key technology and design issues associated with the HINP concept and future work recommendations are also identified.

Chew, Gilbert↗
NASA NTRS2014

Space Launch System Development Status

Development of NASA's Space Launch System (SLS) heavy lift rocket is shifting from the formulation phase into the implementation phase in 2014, a little more than three years after formal program approval. Current development is focused on delivering a vehicle capable of launching 70 metric tons (t) into low Earth orbit. This "Block 1" configuration will launch the Orion Multi-Purpose Crew Vehicle (MPCV) on its first autonomous flight beyond the Moon and back in December 2017, followed by its first crewed flight in 2021. SLS can evolve to a130-t lift capability and serve as a baseline for numerous robotic and human missions ranging from a Mars sample return to delivering the first astronauts to explore another planet. Benefits associated with its unprecedented mass and volume include reduced trip times and simplified payload design. Every SLS element achieved significant, tangible progress over the past year. Among the Program's many accomplishments are: manufacture of Core Stage test panels; testing of Solid Rocket Booster development hardware including thrust vector controls and avionics; planning for testing the RS-25 Core Stage engine; and more than 4,000 wind tunnel runs to refine vehicle configuration, trajectory, and guidance. The Program shipped its first flight hardware - the Multi-Purpose Crew Vehicle Stage Adapter (MSA) - to the United Launch Alliance for integration with the Delta IV heavy rocket that will launch an Orion test article in 2014 from NASA's Kennedy Space Center. Objectives of this Earth-orbit flight include validating the performance of Orion's heat shield and the MSA design, which will be manufactured again for SLS missions to deep space. The Program successfully completed Preliminary Design Review in 2013 and Key Decision Point C in early 2014. NASA has authorized the Program to move forward to Critical Design Review, scheduled for 2015 and a December 2017 first launch. The Program's success to date is due to prudent use of proven technology, infrastructure, and workforce from the Saturn and Space Shuttle programs, a streamlined management approach, and judicious use of new technologies. The result is a safe, affordable, sustainable, and evolutionary path to development of an unprecedented capability for future missions across the solar system. In an environment of economic challenges, the nationwide SLS team continues to meet ambitious budget and schedule targets. This paper will discuss SLS program and technical accomplishments over the past year and provide a look at the milestones and challenges ahead.

Lyles, Garry↗
NASA NTRS2014

NASA's Space Launch System Development Status

Development of the National Aeronautics and Space Administration's (NASA's) Space Launch System (SLS) heavy lift rocket is shifting from the formulation phase into the implementation phase in 2014, a little more than 3 years after formal program establishment. Current development is focused on delivering a vehicle capable of launching 70 metric tons (t) into low Earth orbit. This "Block 1" configuration will launch the Orion Multi-Purpose Crew Vehicle (MPCV) on its first autonomous flight beyond the Moon and back in December 2017, followed by its first crewed flight in 2021. SLS can evolve to a130t lift capability and serve as a baseline for numerous robotic and human missions ranging from a Mars sample return to delivering the first astronauts to explore another planet. Benefits associated with its unprecedented mass and volume include reduced trip times and simplified payload design. Every SLS element achieved significant, tangible progress over the past year. Among the Program's many accomplishments are: manufacture of core stage test barrels and domes; testing of Solid Rocket Booster development hardware including thrust vector controls and avionics; planning for RS- 25 core stage engine testing; and more than 4,000 wind tunnel runs to refine vehicle configuration, trajectory, and guidance. The Program shipped its first flight hardware - the Multi-Purpose Crew Vehicle Stage Adapter (MSA) - to the United Launch Alliance for integration with the Delta IV heavy rocket that will launch an Orion test article in 2014 from NASA's Kennedy Space Center. The Program successfully completed Preliminary Design Review in 2013 and will complete Key Decision Point C in 2014. NASA has authorized the Program to move forward to Critical Design Review, scheduled for 2015 and a December 2017 first launch. The Program's success to date is due to prudent use of proven technology, infrastructure, and workforce from the Saturn and Space Shuttle programs, a streamlined management approach, and judicious use of new technologies. The result is a safe, affordable, sustainable, and evolutionary path to development of an unprecedented capability for future missions across the solar system. In an environment of economic challenges, the nationwide SLS team continues to meet ambitious budget and schedule targets. This paper will discuss SLS Program and technical accomplishments over the past year and provide a look at the milestones and challenges ahead.

Lyles, Garry↗
NASA NTRS1971

An analysis of approach navigation accuracy and guidance requirements for the grand tour mission to the outer planets

The navigation and guidance process for the Jupiter, Saturn and Uranus planetary encounter phases of the 1977 Grand Tour interior mission was simulated. Reference approach navigation accuracies were defined and the relative information content of the various observation types were evaluated. Reference encounter guidance requirements were defined, sensitivities to assumed simulation model parameters were determined and the adequacy of the linear estimation theory was assessed. A linear sequential estimator was used to provide an estimate of the augmented state vector, consisting of the six state variables of position and velocity plus the three components of a planet position bias. The guidance process was simulated using a nonspherical model of the execution errors. Computation algorithms which simulate the navigation and guidance process were derived from theory and implemented into two research-oriented computer programs, written in FORTRAN.

Jones, D. W.↗
NASA NTRS2019

Navigation accuracy at Jupiter and Saturn using optical observations of planetary satellites

Autonomous on-board navigation has the potential to enable new types of missions and decrease reliance on NASA’s Deep Space Network for navigation purposes. Previous results have shown that navigating with only optical images of asteroids is feasible for inner planet cruise. In this study, we show that images of natural satellites can be used to navigate during approach and tour phases around the gas giants. We investigate the Jupiter and Saturn systems here, and specifically assess the performance of optical-only navigation for the Juno, Europa Clipper, and Cassini trajectories. Early approach phases and tours at Jupiter would require radiometric data to navigate, but the performance of optical-only data rivals the as-flown performance for Cassini at Saturn.

Broschart, Stephen B.↗
NASA NTRS1995

Accuracy of wet troposphere radio path delay estimated from infrared emission

Several radio science applications require determination of the excess radio-propagation path delay caused by the Earth's atmosphere. These include very long baseline interferometry, spacecraft tracking, and potentially, detection of gravitational waves utilizing a link to a distant interplanetary spacecraft. At Ka band, the major source of variability of path delay is the fluctuations in the moisture content of the troposphere. The path delay characterization requirements for a planned gravitational wave experiment are novel and challenging. the error contribution to the phase observations due to path delay variation must be reduced by nearly two orders of magnitude over that occurring naturally on time scales of 100 to 10,000 seconds. Current approaches relying on microwave water vapor radiometry with ancillary data can deliver one order of magnitude calibration of these fluctuations, and more advanced systems are under development within the 2001-2002 time frame of the Cassini Mission to Saturn. The current work evaluates the potential for an alternative observational approach, using a ground-based Fourier transform spectrometer.

Parker, J. W.↗
NASA NTRS1996

Market-Based Approaches to Managing Science Return from Planetary Missions

The return of science is the fundamental objective of any planetary mission. However, which constellation of science observations constitute the best return of science is hard to evaluate. Past approaches toward planning science observations have been based on co-location of payload scientists who debate the merits of which investigation had the stronger science. This advocacy approach is time-consuming and does not provide appropriate incentives for science teams to reveal their trade-offs. An alternative approach, currently under evaluation by the Cassini Mission to Saturn, is one based on providing better incentives to the science teams. Incentives can produce better tradeoffs because the individuals who can make the best decisions about which science observations to propose, what resources are required to implement the observations, and which observations are most important are the science team's Principle Investigators (PI) themselves.

mission↗
NASA NTRS1974

Science objectives and the Mariner Jupiter/Saturn 1977 mission design

The two Mariner spacecraft to be launched in 1977 to fly by Jupiter and Saturn require a mission design which is heavily dependent on science objectives. These science objectives translate into trajectory requirements imposed by one or more of the eleven instruments aboard Mariner such as distance of closest approach, inclination, occultation, lighting, etc., at the bodies of interest. Also, Jupiter and Saturn cannot be considered as individual targets but as miniature solar systems, where the mission design must apply to the Jovian and Saturnian satellites, and to Saturn's rings. The major objective of this analysis is to translate the science desires into the mission possibilities. Each object, be it a Galilean satellite, Titan, or the ring of Saturn, provides a unique region suitable for scientific investigation for the on-board instruments. Some of these trajectory regions overlap, others do not. Thus, critical choices must be made in selecting the trajectories to be flown by the two Mariner spacecraft. Such a choice, though preliminary, has been made by the Mariner Jupiter/Saturn 1977 (MJS'77) science teams, and a brief discussion of the selection process and the pair of trajectories chosen is presented in this paper.

Penzo, P. A.↗
NASA NTRS1980

Pioneer Saturn infrared radiometer - Preliminary results

Preliminary results of the infrared radiometer experiment on Pioneer Saturn are reported. The instrument made use of two broadband channels centered at 20 and 45 microns which scan at a fixed 75-deg angle with respect to the spacecraft spin axis to acquire 10,000 image pairs of Saturn and its rings in the 2.5 h before closest approach, as well as several observations of Titan. The intensities of radiation observed in both bands indicate an effective temperature of 94.4 + or - 3 K for the planet, implying a total emission greater than twice the absorbed sunlight. Infrared data also indicates a molecular abundance of 0.85 for H2 relative to H2 + He, which can be improved by comparing the derived temperature profiles and radio occultation data. Planetary temperatures are found to range from a minimum of 83 to 140 K at the 1 bar level, with differences of 2.5 K between belts and zones up to the 0.06-bar level, while ring temperatures range from 60 to 70 K on the illuminated side and from less than 60 to 67 K in the planet's shadow and average 55 K on the unilluminated side. Preliminary estimates indicate a 45-micron brightness temperature of 80 + or - 10 K for Titan.

Ingersoll, A. P.↗
NASA NTRS1990

Saturn orbit insertion options for the Cassini mission

The main objectives of the Cassini mission are to deliver a spacecraft into orbit about Saturn and a Probe into the atmosphere of Titan. Two fundamental constraints drive the design of the initial Saturn orbit and thus affect the mission performance. The first requirement is safe passage through the ring system upon Saturn arrival; the second is delivery of the Probe to Titan with an acceptable relative approach velocity. These constraints lead to the selection of a dual-burn insertion strategy, with maneuvers at periapsis and apoapsis of the initial orbit. Additional science goals constrain the Saturn arrival date and may affect the timing of the orbit insertion burn.

Weinstein, S. S.↗
NASA NTRS1984

The helium abundance of Saturn from Voyager measurements

The helium abundance in the atmosphere of Saturn is obtained from Voyager measurements by two methods. The first method combines infrared spectra and vertical profiles derived from radio occultation measurements and yields a hydrogen mole fraction of q = 0.963 + or - 0.024 corresponding to a helium mass fraction of Y = 0.06 + or - 0.05. The estimated errors are primarily due to uncertainties in the radio occultation profile and in the abundance of methane, which contributes significantly to the mean molecular weight. The second method is based on the direct inversion of infrared spectra and yields values consistent with those from the first method; however, examination of the sensitivities of the two methods indicates that in the Saturnian case the first approach provides more accurate results. Comparison of the helium abundance of Saturn with that of Jupiter and the sun suggests that helium precipitation is significant in Saturn but may not have begun in Jupiter.

Conrath, B. J.↗
NASA NTRS1974

Approach guidance for outer planet Pioneer missions

An overall parametric system analysis of the use of an optical approach guidance measurement system (using a V-slit electrooptical 'star-pipper') onboard a Pioneer-type spin-stabilized spacecraft for outer planet missions. Optical measurements of satellites of Saturn and Uranus against the star background are considered. Measurement geometry and spacecraft attitude are evaluated in depth with respect to two Pioneer missions: Saturn-Uranus and Jupiter-Uranus atmospheric entry probe missions with departure from Earth in November/December, 1980. A preliminary evaluation of long-term attitude stability measurements of Pioneer 10 is presented in the Appendix. The major conclusions are: (1) at Saturn flyby, viewing some medium period satellites can provide the best measurement results. (2) At Uranus approach, viewing the planet may give best measurements if early bus-probe separation is required. (3) Final measurement accuracy depends on the data format transmitted to Earth and the applied data interpretation techniques.-

Bejczy, A. K.↗