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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Dynamics of incremental motion devices associated with planetary exploration spacecraft

Incremental motion devices provide accurate and rapid movement of spacecraft science platforms, antennas and related mechanisms. The paper considers the computerized simulation of a stepper motor/gear train/ science platform system that will be launched on the Mariner Jupiter Saturn 1977. It was determined that a smaller stepper motor could be used as the prime mover for the science platform, and it was concluded that the existing digital controller was unable to achieve the required pointing accuracy, and a new controller design was necessary.

Hughes, R. O.↗
NASA NTRS1990

System control of an autonomous planetary mobile spacecraft

The goal is to suggest the scheduling and control functions necessary for accomplishing mission objectives of a fairly autonomous interplanetary mobile spacecraft, while maximizing reliability. Goals are to provide an extensible, reliable system conservative in its use of on-board resources, while getting full value from subsystem autonomy, and avoiding the lure of ground micromanagement. A functional layout consisting of four basic elements is proposed: GROUND and SYSTEM EXECUTIVE system functions and RESOURCE CONTROL and ACTIVITY MANAGER subsystem functions. The system executive includes six subfunctions: SYSTEM MANAGER, SYSTEM FAULT PROTECTION, PLANNER, SCHEDULE ADAPTER, EVENT MONITOR and RESOURCE MONITOR. The full configuration is needed for autonomous operation on Moon or Mars, whereas a reduced version without the planning, schedule adaption and event monitoring functions could be appropriate for lower-autonomy use on the Moon. An implementation concept is suggested which is conservative in use of system resources and consists of modules combined with a network communications fabric. A language concept termed a scheduling calculus for rapidly performing essential on-board schedule adaption functions is introduced.

Dias, William C.↗
NASA NTRSDate not supplied

Proposed Protocols for Defining Requirements and Sizing of Media-Based Filters for Spacecraft and Planetary Lander Applications

The air quality control equipment aboard future deep space exploration vehicles provide the vital function of maintaining a clean cabin environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of sedimentation in low gravity, and can experience short duration peak loading of dust from planetary surfaces for Lunar or Mars landers. The filter industry has established methods to properly size filters for a given particulate load, but requirements for the space or planetary application introduce additional consideration. In this work, a methodology for properly evaluating and sizing particulate filters for a Lunar surface pressurized environment will be presented, including estimating the loading and particle size distributions of the loading based on mission requirements. In addition, a scaling analysis from single filter media sheet to full-scale filters for this application, based on recent testing, will also be presented. These results of this study may provide meaningful guidance for properly designing media-based particulate filters for the air revitalization challenges in future deep space exploration missions.

media-based filters↗
NASA NTRS1991

SHARP: Spacecraft Health Automated Reasoning Prototype

The planetary spacecraft mission OPS as applied to SHARP is studied. Knowledge systems involved in this study are detailed. SHARP development task and Voyager telecom link analysis were examined. It was concluded that artificial intelligence has a proven capability to deliver useful functions in a real time space flight operations environment. SHARP has precipitated major change in acceptance of automation at JPL. The potential payoff from automation using AI is substantial. SHARP, and other AI technology is being transferred into systems in development including mission operations automation, science data systems, and infrastructure applications.

Atkinson, David J.↗
NASA NTRS2019

Planetary Protection Technologies for Planetary Science Instruments, Spacecraft, and Missions: Report of the NASA Planetary Protection Technology Definition Team (PPTDT)

Planetary bodies like Mars, Europa, and Enceladus pose the question, "How to study them without contaminating them and destroying future prospects to detect life, if it is there?" The natural trade-off, of course, is that the cleaner your spacecraft, the more you can explore such a body without risk of contaminating it. As chartered by NASA Headquarters, the Planetary Protection Technology Definition Team (PPTDT) was asked to provide a report covering six different areas related to the engineering and technology challenges of implementing planetary protection requirements on solar system exploration missions, including: Assessment of technical and engineering challenges to applying available microbial-reduction methods, including recontamination prevention, to spacecraft hardware and instruments, to meet current NASA requirements on preventing the forward contamination of potentially habitable worlds by future spacecraft missions (orbiters, atmospheric missions, landers, penetrators, and drills); Identification of spacecraft and instrument materials known to be compatible with existing planetary protection protocols; Planetary protection protocols/processes available or which appear promising, and areas ripe for technological development; The technical and engineering challenges in ensuring that spacecraft hardware and instruments can meet organic cleanliness requirements needed to ensure high confidence in differentiating Earth contamination from extraterrestrial signals to avoid false negative as well as false positive results; Approaches for mitigating the identified challenges that would allow instruments to be flown successfully at the required levels of cleanliness and microbial reduction, beginning with identification of commonly used materials and spacecraft hardware that are compatible (or particularly vulnerable) to planetary protection protocols; Engineering, technology, and scientific research and development that could be funded by NASA to provide future capabilities to field scientific instruments and spacecraft on missions that require either subsystem or system-level microbial reduction and recontamination prevention.

John D. Rummel↗
NASA NTRS1979

Spacecraft automated operations

Trends in automation of planetary spacecraft are examined using data from missions as far back as Mariner '67 and up to the highly sophisticated Galileo. Nine design considerations which influence the degree of automation such as protection against catastrophic failures, highly repetitive functions, loss of spacecraft communications, and the need for near-real-time adaptivity are discussed. Rapid growth of automation is shown in terms of on-board hardware by plots of number of processors on board, the average speed of processors, and total core memory. The number of commands transmitted from the ground has grown to 5 million bits in Voyager, so that increases in mission complexity have increased both in spacecraft automation and ground operations. Achieving greater automation by transferring ground operations to the spacecraft with the current means of controlling missions, are considered noting proposed changes. For the future, improved computer technology, more microprocessors and increased core storage will be used, and the number of automated functions and their complexity will grow. It is concluded that using the growing computational capability of spacecraft will achieve more autonomy thus reversing the trend of increased mission complexity and cost.

Bird, T. H.↗
NASA NTRS1987

Lightweight spacecraft propulsion system selection

Various methods of significantly reducing the mass of planetary spacecraft propulsion systems were addressed. Because of the Space Shuttle Challenger accident, the availability of the Space Transportation System for planetary missions may be limited. Mounting a future planetary mission with lower-energy launch vehicles will require a significant reduction in the spacecraft mass. Smaller launch vehicles for planetary missions were considered. In this study, the assumed payload capability for the planetary missions were considered. In this study, the assumed payload capability for the planetary missions was restricted to the Delta and the Atlas-Centaur launch vehicles. Several propulsion and propulsion-related technologies for spacecraft mass reduction were investigated; ion, arcjet, resistojet, and Magneto-Plasma-Dynamic propulsion and earth-storable high-energy propulsion system thrusters were candidates. The propulsion-related technologies included a start-basket Propellant Management Device, a nitrogen tetroxide diaphragm, and a solid-cryogen cooler. Xenon-ion propulsion allowed the greatest mass reduction.

Palaszewski, B.↗
NASA NTRS1984

Instrument pointing technology for spaceborne science missions of the 1990's

The technologies which will permit sub-0.1 arcsec pointing accuracies on spacecraft in the 1990s are examined, along with the accuracies required and the current state of the art. Of particular interest are multi-mission spacecraft. Pointing accuracy can only be obtained by integrating the instrument (telescope) as part of the spacecraft, minimizing disturbances and using reaction wheels for pointing. The pointer could be isolated from complex spacecraft disturbances by soft mechanical mounts, e.g., inflatible tethers, guy-wire suspension and fluidic pointing systems. All design options are being explored for the Space Station, Earth Observing System, Co-orbiting platform and GEO platform spacecraft, and for near-term planetary spacecraft which will employ nuclear electric propulsion.

Laskin, R. A.↗