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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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Experimental design for the Mariner mission to Comet Encke is considered, examining the following experiments: volatile and nonvolatile chemical analysis, an imaging system for the comet nucleus, the ultraviolet spectrometer, and magnetic field and plasma experiments. Mission design is discussed, emphasizing the mission profile, trajectory and targeting and the spacecraft design.
Extraterrestrial resources for space processing of chemicals, in general, and propellants, in particular, are explored quantitatively. It is seen that, for several candidate space mission scenarios, space processing of both space resources and earth-carried resources can make decisive differences in the mission success for a given payload. To fix ideas and demonstrate trends, the specific case of water splitting to extract oxygen, discard (or use without storage) the resulting hydrogen, and burn earth-carried noncryogenic liquid fuel(s) in a simple rocket motor, designed for periodic thrusting, is treated in some detail. Experimental hardware is assembled and demonstrated to perform adequately, besides showing compactness of the space-packaged 'capsule' module that is self-contained. Building upon previous studies, the concept of in situ propellant production (ISPP) is reexamined in light of more recent energy and materials technologies. Missions to comets and Mars Sample Return are mentioned as candidate scenarios. The mission duration, reliability-repairability of hardware, resource availability in low earth orbit (LEO), and the thrust requirements are considered in turn. It is seen that space storage of hydrogen for extended durations (5-10 years) involves problems that require detailed studies, besides involving many presently unanswered issues. A study of the energy option in LEO and in deep space is developed in simple terms. The different solar, radioisotope, and nuclear power sources are mentioned. Storage and handling of raw and processed chemicals are considered.
Spacecraft-comet rendezvous trajectory analyzed in terms of comet properties and spacecraft capabilities to determine feasibility of interception mission
The NASA Stardust mission to comet Wild 2 returned to Earth in 2006 with cometary material trapped in aerogel. The cometary particles were captured at a relative velocity of 6.1 km/s, creating three-dimensional (3D) tracks containing void space, compressed aerogel, melted aerogel, and fragmented cometary material. Each track represents a unique hypervelocity impact event. The nature of each track forming event, including the original state of the impactor, is recorded in 3D track morphology and material distribution. Tracks were cut from sampling tiles in thin aerogel “keystones” translucent to optical light.
The results of a joint JPL/CSFC feasability study of a low-cost comet sample return flyby mission are presented. It is shown that the mission could be undertaken using current earth orbiter spacecraft technology in conjunction with pathfinder or beacon spacrcraft. Detailed scenarios of missions to the comets Honda-Mrkos-Pajdusakova (HMP), comet Kopff, and comet Giacobini-Zinner (GZ) are given, and some crossectional diagrams of the spacecraft designs are provided.
The concept used in the design of the Mariner Mark II (MMII) spacecraft is consistent with the solar system exploration strategies which were developed by the Space Science Board of the National Academy of Sciences. The missions to comets, main belt asteroids, and outer planets are sufficiently similar to make possible a use of almost all of the design, hardware, and software in most engineering subsystems, without significant modification, for subsequent missions. Mariner Mark II missions are discussed, taking into account a comet rendezvous with asteroid flyby, the Saturn Flyby/Titan Probe, the Cassini or Saturn Orbiter/Titan Probe, the Main Belt Asteroid Rendezvous mission, the Uranus Flyby/Uranus Probe mission, and the Neptune Flyby/Neptune Probe mission.
The paper evaluates and compares the performance of earth-storable and space-storable liquid bipropellant propulsion systems in high-energy planetary mission applications, including specifically Saturn and Mercury orbiters, as well as asteroid and comet rendezvous missions. The discussion covers a brief review of the status of space-storable propulsion technology, along with an illustrative propulsion module design for a three-axis stabilized outer planet and cometary mission spacecraft of the Mariner class. The results take revised Shuttle/Upper Stage performance projections into account. It is shown that in some of the missions the performance improvement achievable in the ballistic transfer mode with space-storable spacecraft propulsion can provide a possible alternative to the use of solar-electric propulsion.
The Mariner Mark II spacecraft is a modular design that can be inexpensively reconfigured for different missions beyond the inner solar system. The first three missions will be described. The Comet Rendezvous Asteroid Flyby mission has a February 1993 launch to comet Tempel 2. The Cassini mission has a May 1995 launch to Saturn and Titan. The third mission is a Comet Nucleus Sample Return launch in 1998.
This paper describes the design options, processes and tradeoffs that occur during the establishment of viable Ion Drive vehicle and mission designs. The options identify those internal vehicle design alternatives which are being considered for future Ion Drive missions, such as sunlight concentrating arrays and direct drive thrust subsystems, and their effect on mission performance. Also, the highly interactive nature of the Ion Drive design process, which occurs between the spacecraft and mission designers, is described. The results of design tradeoffs, performed for three Ion Drive comet rendezvous missions, are presented. These results include the following: (1) the power profile is determined primarily by the trajectory while second order effects include the solar cell characteristics and array concentration factor and degradation; and (2) the dominant parameter in mission performance determination, Ion Propulsion Module (IPM) mass, and IPM design, is the total cell power evaluated without concentration, at the beginning of life and at 1 AU.
The configuration, trajectories, and payloads of a spinning Earth-orbiting satellite designed by ESA for a post-perihelion flythrough (Giotto mission) of Comet Halley are described. Experiments approved for use on two identical three-axis stabilized Venera spacecraft destined to encounter the comet after releasing probes to Venus are listed as well as the instruments to be carried on Japan's Planet-A flyby mission. The main features launch windows are given for each spacecraft.
The present workshop on the modeling, simulation, and sounding of cometary nuclei discusses the Rosetta comet-nucleus sample return mission, the importance of comet models in the design of the Rosetta mission, the challenge of sample acquisition in a cometary environment, and a simulation of Rosetta on-comet operations. Attention is given to HST observations of the inner coma of Comet Levy 1990c, cometary coma particulate modeling for the Rosetta mission aphelion rendezvous, recent gas flux modeling and applications of cometary nuclei, and the 3D time-dependent modeling of comet nucleus surface layers. Topics addressed include models of cometary nuclei and future space mission, the composition of cometary materials, experiments with cometary analogs at the DLR, and crust formation in cometary analogs. Also considered are gaseous products from VUV photolysis of cometary solids, cosmic ray modification of organic cometary matter as simulated by cyclotron irradiation, and KOSI comet simulation experiments.
Three Advanced Design Projects have been completed this academic year at Penn State. At the beginning of the fall semester the students were organized into eight groups and given their choice of either a comet nucleus or an asteroid sample return mission. Once a mission had been chosen, the students developed conceptual designs. These were evaluated at the end of the fall semester and combined into three separate mission plans, including a comet nucleus same return (CNSR), a single asteroid sample return (SASR), and a multiple asteroid sample return (MASR). To facilitate the work required for each mission, the class was reorganized in the spring semester by combining groups to form three mission teams. An integration team consisting of two members from each group was formed for each mission so that communication and information exchange would be easier among the groups. The types of projects designed by the students evolved from numerous discussions with Penn State faculty and mission planners at the Johnson Space Center Human/Robotic Spacecraft Office. Robotic sample return missions are widely considered valuable precursors to manned missions in that they can provide details about a site's environment and scientific value. For example, a sample return from an asteroid might reveal valuable resources that, once mined, could be utilized for propulsion. These missions are also more adaptable when considering the risk to humans visiting unknown and potentially dangerous locations, such as a comet nucleus.
An analysis has been conducted in connection with plans for a study of Halley's Comet during its 1986 apparition. The use of low-thrust vehicles, utilizing an ion drive system, is being considered for a comet rendezvous mission. A preliminary trajectory for the Halley rendezvous mission calls for launch on June 20, 1982, followed by rendezvous on December 21, 1985. The navigation analysis described focuses on the terminal approach to Halley, the 60-day period preceding rendezvous. Navigation analysis assumptions are examined, taking into account navigation error sources, radio tracking, onboard optical data, earth-based comet observations, and orbit determination and guidance strategies. The preliminary mission design considers a rendezvous at approximately 56,000 km from the comet nucleus (6,000 km outside the dust envelope). Navigation performance is measured in terms of comet-relative position and velocity errors at encounter. Variations to the baseline navigation study provide illustrations concerning the close link between delivery accuracy and stochastic thrust errors.
This paper presents an assessment of delivered payload capability for a number of selected rendezvous missions to periodic comets with launch opportunities through the years 1986-1996. These missions are chosen using a selection criteria that considers both expected scientific interest and earth-based sighting considerations. Some 22 mission opportunities are found that satisfies the selection criteria. Spacecraft performance is presented for each mission opportunity based on use of a space shuttle, a twin stage inertial-upper-stage, and a conceptual solar-electric-propulsion-system with a nominal rendezvous 50 days before comet perihelion. Additional trajectory and propulsion enhancements are investigated for several comet rendezvous missions in order to improve spacecraft performance. An indirect transfer trajectory for an Encke mission is shown to offer substantial delivered payload. In addition the use of concentrator solar arrays is considered for several of the more interesting comet missions.
A highly abridged review of new relevant results from the observations of Comet Kohoutek is followed by an outline summary of our basic knowledge concerning comets, both subjects being confined to data related to the nature and origin of comets rather than the phenomena (for example, plasma phenomena are omitted). The discussion then centers on two likely places of cometary origin in the developing solar system, the proto-Uranus-Neptune region versus the much more distant fragmented interstellar cloud region, now frequented by comets of the Opik-Oort cloud. The Comet Kohoutek results add new insights, particularly with regard to the parent molecules and the nature of meteoric solids in comets, to restrict the range of the physical circumstances of comet formation. A few fundamental and outstanding questions are asked, and a plea made for unmanned missions to comets and asteroids in order to provide definitive answers as to the nature and origin of comets, asteroids, and the solar system generally.
A terminal guidance and navigation scheme developed in earlier work was modified and evaluated for a solar electric propulsion rendezvous mission to comet Encke. The scheme is intended for autonomous, on-board use. The guidance algorithm is based on optimal control theory and minimizes the time integrated square of thrust acceleration. The navigation algorithm employs a modified Kalman filter set in measurement variables. Random sequences were generated to simulate measurement errors, and the evaluation was conducted with detailed numerical computations which include actual motions of spacecraft and comet. The evaluations showed that the scheme attains rendezvous and maintains station after rendezvous within less than 10 km for estimated best measurements and within less than 100 km for estimated worst measurements. The measurements required are angles, range, and range rate. Angles and range appear to be absolutely necessary; range rate is not as strong a measurement type, and further modifications of the filter will allow a scheme that does not require the rate measurements.