Guidance and control parameters of a planetary cartographic probe.
Orbit selection rules for planetary cartographic spacecraft derived from relations connecting camera angle, view field and imaging resolution
Moskowitz, S.↗
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Results for “PLANETARY ORBIT”
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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Mariner/Jupiter/Saturn navigation in the presence of massive planetary satellites
Orbit determination accuracies attainable during a Mariner/Jupiter/Saturn encounter have been established by means of covariance analyses. Advanced earth-based multistation radiometric data, optical data consisting of star/satellite pictures provided by a narrow-angle TV camera on board the spacecraft, and batch sequential filtering methods were employed. An evaluation of sequential filter sensitivities to errors in modeling small nongravitational spacecraft accelerations is presented. Selected covariances developed in the orbit determination analysis are used in an investigation of the trajectory correction costs associated with a close Ganymede encounter. The 99 percentile Delta V contours in the Ganymede aiming plane are obtained for satellite encounters before or after Jupiter closed approach, and the sources of the dominant contributions to the Delta V costs are identified.
Hildebrand, C. E.↗
Radio occultation measurements of planetary atmospheres and ionospheres from an orbiting pair.
Radio occultation measurements of planetary atmospheres and ionospheres from orbiting pair
Goff, R. W.↗
Orbital evolution of the PSR1257+12 planetary system
The detection of orbital perturbation effects in the PSR1257+12 timing data would provide irrefutable confirmation that planets are indeed orbiting the pulsar. Here we give an overview of how perturbation effects are expected to affect the orbital elements of the two planets over the next few years. In particular, we give a simple calculation of resonant perturbations, including the nonlinear effects which could be important if sin i less than about 0.1. We also present a new analysis of the effects of close encounters between the two planets and we discuss their detectability.
Rasio, Frederic A.↗
Moon Search Algorithms for NASA's Dawn Mission to Asteroid Vesta
A moon or natural satellite is a celestial body that orbits a planetary body such as a planet, dwarf planet, or an asteroid. Scientists seek understanding the origin and evolution of our solar system by studying moons of these bodies. Additionally, searches for satellites of planetary bodies can be important to protect the safety of a spacecraft as it approaches or orbits a planetary body. If a satellite of a celestial body is found, the mass of that body can also be calculated once its orbit is determined. Ensuring the Dawn spacecraft's safety on its mission to the asteroid Vesta primarily motivated the work of Dawn's Satellite Working Group (SWG) in summer of 2011. Dawn mission scientists and engineers utilized various computational tools and techniques for Vesta's satellite search. The objectives of this paper are to 1) introduce the natural satellite search problem, 2) present the computational challenges, approaches, and tools used when addressing this problem, and 3) describe applications of various image processing and computational algorithms for performing satellite searches to the electronic imaging and computer science community. Furthermore, we hope that this communication would enable Dawn mission scientists to improve their satellite search algorithms and tools and be better prepared for performing the same investigation in 2015, when the spacecraft is scheduled to approach and orbit the dwarf planet Ceres.
planetary sciences↗
Orbital stability constraints on the nature of planetary systems
A fully self-consistent, N-body computer code is used to study conditions under which model planetary systems, each consisting of a star and two 'planetary' companions, become orbitally unstable as a result of gravitational interactions between the companions. A formula describing a necessary condition for orbital stability is given. It is found that giant gaseous protoplanets of the type postulated by Cameron (1978) to be precursors of the present-day solar system planets could have stable orbits for at least 10,000 years, the time required for significant core formation in a typical giant gaseous protoplanet.
Graziani, F.↗
Economics of ion propulsion for large space systems
This study of advanced electrostatic ion thrusters for space propulsion was initiated to determine the suitability of the baseline 30-cm thruster for future missions and to identify other thruster concepts that would better satisfy mission requirements. The general scope of the study was to review mission requirements, select thruster designs to meet these requirements, assess the associated thruster technology requirements, and recommend short- and long-term technology directions that would support future thruster needs. Preliminary design concepts for several advanced thrusters were developed to assess the potential practical difficulties of a new design. This study produced useful general methodologies for assessing both planetary and earth orbit missions. For planetary missions, the assessment is in terms of payload performance as a function of propulsion system technology level. For earth orbit missions, the assessment is made on the basis of cost (cost sensitivity to propulsion system technology level).
Masek, T. D.↗
The Design, Planning and Control of Robotic Systems in Space
In the future, robotic systems will be expected to perform important tasks in space, in orbit and in planetary exploration. In orbit, current technology requires that tasks such as the repair, construction and maintenance of space stations and satellites be performed by astronaut Extra Vehicular Activity (EVA). Eliminating the need for astronaut EVA through the use of space manipulators would greatly reduce both mission costs and hazards to astronauts. In planetary exploration, cost and logistical considerations clearly make the use of autonomous and telerobotic systems also very attractive, even in cases where an astronaut explorer might be in the area. However, such applications introduce a number of technical problems not found in conventional earth-bound industrial robots. To design useful and practical systems to meet the needs of future space missions, substantial technical development is required, including in the areas of the design, control and planning. The objectives of this research program were to develop such design paradigms and control and planning algorithms to enable future space robotic systems to meet their proposed mission objectives. The underlying intellectual focus of the program is to construct a set of integrated design, planning and control techniques based on an understanding of the fundamental mechanics of space robotic systems. This work was to build upon the results obtained in our previous research in this area supported by NASA Langley Research Center in which we have made important contributions to the area of space robotics.
Dubowsky, Steven↗
The Design, Planning and Control of Robotic Systems in Space
In the future, robotic systems will be expected to perform important tasks in space, in orbit and in planetary exploration. In orbit, current technology requires that tasks such as the repair, construction and maintenance of space stations and satellites be performed by astronaut Extra Vehicular Activity (EVA). Eliminating, the need for astronaut EVA through the use of space manipulators would greatly reduce both mission costs and hazards to astronauts. In planetary exploration, cost and logistical considerations clearly make the use of autonomous and telerobotic systems also very attractive, even in cases where an astronaut explorer might be in the area. However, such applications introduce a number of technical problems not found in conventional earth-bound industrial robots. To design useful and practical systems to meet the needs of future space missions, substantial technical development is required, including in the areas of the design, control and planning. The objectives of this research program were to develop such design paradigms and control and planning algorithms to enable future space robotic systems to meet their proposed mission objectives. The underlying intellectual focus of the program is to construct a set of integrated design, planning and control techniques based on an understanding of the fundamental mechanics of space robotic systems. This work was to build upon the results obtained in our previous research in this area supported by NASA Langley Research Center in which we have made important contributions to the area of space robotics. This program was proposed and accepted as a three year research program, a period of time necessary to make the type of fundamental developments to make a significant contributions to space robotics. Unfortunately, less than a year into the program it became clear that the NASA Langley Research Center would be forced by budgetary constraints to essentially leave this area of research. As a result, the total funding we received under this grant represented approximately one year of the original, proposed and approved, funding. For some time, there was substantial uncertainty that even this very reduced level of funding would be provided. The spending of the reduced available funds was spread just over two years to provide the support to permit the MS students who had joined the program to receive their master's degree and terminate their studies in this area.
Dubowsky, Steven↗
Use of orbit-to-orbit shuttles for hyperbolic rendezvous with returning planetary spacecraft
Use of orbit-to-orbit shuttles for hyperbolic rendezvous with returning interplanetary spacecraft
Brooks, D. R.↗
The NASA low thrust propulsion program
The NASA OAST Propulsion, Power, and Energy Division supports a low thrust propulsion program aimed at providing high performance options for a broad range of near-term and far-term mission and vehicles. Low thrust propulsion has a major impact on the mission performance of essentially all spacecraft and vehicles. On-orbit lifetimes, payloads, and trip times are significantly impacted by low thrust propulsion performance and integration features for Earth-to-orbit (ETO) vehicles, Earth-orbit and planetary spacecraft, and large platforms in Earth orbit. Major emphases are on low thrust chemical propulsion, both storables and hydrogen/oxygen; low-power (auxiliary) electric arcjects and resistojets; and high-power (primary) electric propulsion, including ion, magnetoplasmadynamic (MPD), and electrodeless concepts. The major recent accomplishments of the program are presented and their impacts discussed.
Stone, James R.↗
The NASA low thrust propulsion program
The NASA OAST Propulsion, Power, and Energy Division supports a low-thrust propulsion program aimed at providing high-performance options for a broad range of near-term and far-term missions and vehicles. Low-thrust propulsion has a major impact on the mission performance of essentially all spacecraft and vehicles. On-orbit lifetimes, payloads, and trip time are significantly impacted by low-thrust propulsion performance and integration features for earth-to-orbit (ETO) vehicles, earth-orbit and planetary spacecraft, and large platforms in earth orbit. Major emphases are on low-thrust chemical propulsion, both storables and hydrogen/oxygen; low-power (auxiliary) electric arcjets and resistojets; and high-power (primary) electric propulsion, including ion, magnetoplasmadynamic (MPD), and electrodeless concepts. The major recent accomplishments of the program are presented and their impacts discussed.
Stone, James R.↗
Application of Solar-Electric Propulsion to Robotic and Human Missions in Near-Earth Space
Solar-electric propulsion (SEP) is becoming of interest for application to a wide range of missions. The benefits of SEP are strongly influenced by system element performance, especially that for the power system. Solar array performance is increasing rapidly and promises to continue to do so for another 10 to 20 years (Fig. 1). At the same time, cost per watt is decreasing. Radiation hardness is increasing. New concepts for how to design a SEP are emerging. These improvements lead to changes in the best ways to apply SEP technology to missions, and broadening of the practical uses of SEP technology compared to competing technologies. This paper addresses the evolving characteristics of SEP technology from the point of view of mission design, and how mission profile characteristics can be designed to best take advantage of evolving SEP characteristics. Mission concepts include robotic lunar landers and orbiters; scientific planetary spacecraft; delivery of spacecraft to geosynchronous orbit from inclined and low-inclination launch orbits; and lunar cargo delivery from Earth orbit to lunar orbit. Expendable and re-usable SEP profiles are considered. Flight control considerations are abstracted from recent papers by the author to describe how these influence SEP design and operations.
Woodcock, Gordon↗
Viking 1 planetary phase tracking operations: Mars orbit insertion through landing
This article describes tracking operations during the Viking 1 planetary phase. Particular attention is paid to special planning for critical phase tracking operations, and to the degree of success subsequently achieved by these special plans during the actual operations. In-depth coverage is provided for Mars orbit insertion (MOI), periapsis passage tracking, and Lander direct links. The article concludes that on balance, tracking operations during the Viking 1 planetary phase have been effectively implemented and quite successful.
Berman, A. L.↗
Heating problems of entry into planetary atmospheres from supercircular orbiting velocities
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Scala, S. M.↗
In-Space Chemical Propulsion Systems Roadmap
In-space propulsion begins where the launch vehicle upper stage leaves off, performing the functions of primary propulsion, reaction control, station keeping, precision pointing, and orbital maneuvering. The main engines used in space provide the primary propulsive force for orbit transfer, planetary trajectories and extra planetary landing and ascent. The reaction control and orbital maneuvering systems provide the propulsive force for orbit maintenance, position control, station keeping, and spacecraft attitude control. Advanced in-space propulsion technologies will enable much more effective exploration of our Solar System and will permit mission designers to plan missions to "fly anytime, anywhere, and complete a host of science objectives at the destinations" with greater reliability and safety. With wide range of possible missions and candidate propulsion technologies, the question of which technologies are "best" for future missions is a difficult one. A portfolio of propulsion technologies should be developed to provide optimum solutions for a diverse set of missions and destinations. A large fraction of the rocket engines in use today are chemical rockets; that is, they obtain the energy needed to generate thrust by chemical reactions to create a hot gas that is expanded to produce thrust. A significant limitation of chemical propulsion is that it has a relatively low specific impulse (Is, or thrust per mass flow rate of propellant). A significant improvement (>30%) in Is can be obtained by using cryogenic propellants, such as liquid oxygen and liquid hydrogen, for example. Historically, these propellants have not been applied beyond upper stages.
Oxidizers↗
Multiple Transits during a Single Conjunction: Identifying Transiting Circumbinary Planetary Candidates from TESS
We present results of a study on identifying circumbinary planet candidates that produce multiple transits during one conjunction with eclipsing binary systems. The occurrence of these transits enables us to estimate the candidates’ orbital periods, which is crucial as the periods of the currently known transiting circumbinary planets are significantly longer than the typical observational baseline of the Transiting Exoplanet Survey Satellite (TESS). Combined with the derived radii, it also provides valuable information needed for follow-up observations and subsequent confirmation of a large number of circumbinary planet candidates from TESS. Motivated by the discovery of the 1108 day circumbinary planet Kepler-1647, we show the application of this technique to four of Kepler’s circumbinary planets that produce such transits. Our results indicate that in systems where the circumbinary planet is on a low-eccentricity orbit, the estimated planetary orbital period is within <10%–20% of the true value. This estimate is derived from photometric observations spanning less than 5% of the planet’s period, demonstrating the strong capability of the technique. Capitalizing on the current and future eclipsing binaries monitored by NASA’s TESS mission, we estimate that hundreds of circumbinary planet candidates producing multiple transits during one conjunction will be detected in the TESS data. Such a large sample will enable statistical understanding of the population of planets orbiting binary stars and shed new light on their formation and evolution.
Veselin Kostov↗
On the Diversity of Planetary Systems
Models of planet formation and of the orbital stability of planetary systems are described and used to discuss possible characteristics of undiscovered planetary systems. Modern theories of star and planet formation, which are based upon observations of the Solar System and of young stars and their environments, predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. A potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path. The implications of the giant planets found in recent radial velocity searches for the abundances of habitable planets are discussed.
Lissauer, Jack J.↗