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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

On-board emergent scheduling of autonomous spacecraft payload operations

This paper describes a behavioral competency level concerned with emergent scheduling of spacecraft payload operations. The level is part of a multi-level subsumption architecture model for autonomous spacecraft, and it functions as an action selection system for processing a spacecraft commands that can be considered as 'plans-as-communication'. Several versions of the selection mechanism are described, and their robustness is qualitatively compared.

Lindley, Craig A.↗
NASA NTRS1994

Autonomous spacecraft executive and its application to rendezvous and docking

Autonomy is needed for future spacecraft to solve the problems of human operator overload and transmission delay. This paper describes the autonomous spacecraft executive for rendezvous and docking. It is an onboard expert system and has decision making capability for mission planning of nominal and contingency cases. The executive has been developed and verified using a hardware motion based simulator.

Komura, Fuminobu↗
NASA NTRS2002

The Personal Satellite Assistant: An Internal Spacecraft Autonomous Mobile Monitor

This paper presents an overview of the research and development effort at the NASA Ames Research Center to create an internal spacecraft autonomous mobile monitor capable of performing intra-vehicular sensing activities by autonomously navigating onboard the International Space Station. We describe the capabilities, mission roles, rationale, high-level functional requirements, and design challenges for an autonomous mobile monitor. The rapid prototyping design methodology used, in which five prototypes of increasing fidelity are designed, is described as well as the status of these prototypes, of which two are operational and being tested, and one is actively being designed. The physical test facilities used to perform ground testing are briefly described, including a micro-gravity test facility that permits a prototype to propel itself in 3 dimensions with 6 degrees-of-freedom as if it were in an micro-gravity environment. We also describe an overview of the autonomy framework and its components including the software simulators used in the development process. Sample mission test scenarios are also described. The paper concludes with a discussion of future and related work followed by the summary.

Dorais, Gregory A.↗
NASA NTRS2003

Visualizing Decision-making Behaviours in Agent-based Autonomous Spacecraft

The authors will report initial progress on the PIAudit project as a Research Resident Associate Program. The objective of this research is to prototype a tool for visualizing decision-making behaviours in autonomous spacecraft. This visualization will serve as an information source for human analysts. The current visualization prototype for PIAudit combines traditional Decision Trees with Weights of Evidence.

North, Steve↗
NASA NTRS1997

Advanced Simulation Environment for Autonomous Spacecraft

NASA is developing technology to increase spacecraft on-board autonomy, in an effort to reduce overall mission cost and mission operations resources. Achievement of this objective requires the development of a new class of ground-based autonomy testbeds that can enable rapid development, test, and integration of the new autonomous spacecraft flight software.

cost Autonomy Testbed Environment↗
NASA NTRS1996

Spacecraft Autonomous Navigation for Formation Flying Earth Orbiters Using GPS

This paper extends earlier analysis for autonomous orbit determination and control of Earth orbiting spacecraft. The earlier analysis was limited to a single spacecraft with a ground track repeat requirement. This work shows that a similar technique is applicable for two spacecraft flying in formation. Tracking and orbit determination functions are performed using the Global Positioning System (GPS).

spacecraft↗
NASA NTRS1983

Algorithm development for a spacecraft autonomous power system

Two algorithms were developed to demonstrate the implementation of autonomous functions in an existing spacecraft power system. The functions selected for autonomous operation include a typical performance monitoring function, battery state of charge, and a fault detection and response function represented by a battery state of charge below a preselected limit. The constraints imposed by the existing power system configuration are the available data in the telemetry stream and the existing commands and command structure. The areas requiring future development are the degree of battery characterization, the effects of hardware/software faults, and the verification of faults.

Bridgeforth, A. O.↗
NASA NTRS2014

Autonomous Spacecraft Communication Interface for Load Planning

Ground-based controllers can remain in continuous communication with spacecraft in low Earth orbit (LEO) with near-instantaneous communication speeds. This permits near real-time control of all of the core spacecraft systems by ground personnel. However, as NASA missions move beyond LEO, light-time communication delay issues, such as time lag and low bandwidth, will prohibit this type of operation. As missions become more distant, autonomous control of manned spacecraft will be required. The focus of this paper is the power subsystem. For present missions, controllers on the ground develop a complete schedule of power usage for all spacecraft components. This paper presents work currently underway at NASA to develop an architecture for an autonomous spacecraft, and focuses on the development of communication between the Mission Manager and the Autonomous Power Controller. These two systems must work together in order to plan future load use and respond to unanticipated plan deviations. Using a nominal spacecraft architecture and prototype versions of these two key components, a number of simulations are run under a variety of operational conditions, enabling development of content and format of the messages necessary to achieve the desired goals. The goals include negotiation of a load schedule that meets the global requirements (contained in the Mission Manager) and local power system requirements (contained in the Autonomous Power Controller), and communication of off-plan disturbances that arise while executing a negotiated plan. The message content is developed in two steps: first, a set of rapid-prototyping "paper" simulations are preformed; then the resultant optimized messages are codified for computer communication for use in automated testing.

Controls↗
NASA NTRS2000

Hard-real-time resource management for autonomous spacecraft

This paper describes tickets, a computational mechanism for hard-real-time autonomous resource management. Autonomous spacecraftcontrol can be considered abstractly as a computational process whose outputs are spacecraft commands.

Computational mechism autonomous spacecraft↗
NASA NTRS1984

Command and telemetry in autonomous spacecraft design

Some major steps are summarized in the evolution of autonomous design features for planetary exploration spacecraft. The control and data architectures for the Viking, Voyager, and Galileo spacecraft are considered. Telemetry and command capabilities are fundamental features of spacecraft design that have been successfully used for autonomous control. Also discussed is the Autonomous Redundancy and Maintenance Management Subsystem (ARMMS) concept. The software approach to autonomous control provides for modifications to the control process or the addition of new operating features during flight operations.

Turner, P. R.↗
NASA NTRS1998

V & V of A Spacecrafts Autonomous Planner Through Extended Automation

We have introduced and used significant automation during the verification and validation (V & V) of a spacecraft's autonomous planner. This paper describes the problem we faced, the solution we employed, and the applicability of our approach in a general V & V setting.

planning↗
NASA NTRS2004

Software for Autonomous Spacecraft Maneuvers

The AutoCon computer programs facilitate and accelerate the planning and execution of orbital control maneuvers of spacecraft while analyzing and resolving mission constraints. AutoCon-F is executed aboard spacecraft, enabling the spacecraft to plan and execute maneuvers autonomously; AutoCon-G is designed for use on the ground. The AutoCon programs utilize advanced techniques of artificial intelligence, including those of fuzzy logic and natural-language scripting, to resolve multiple conflicting constraints and automatically plan maneuvers. These programs can be used to satisfy requirements for missions that involve orbits around the Earth, the Moon, or any planet, and are especially useful for missions in which there are requirements for frequent maneuvers and for resolution of complex conflicting constraints. During operations, the software targets new trajectories, places and sizes maneuvers, and controls spacecraft burns. AutoCon-G provides a userfriendly graphical interface, and can be used effectively by an analyst with minimal training. AutoCon-F reduces latency and supports multiple-spacecraft and formation-flying missions. The AutoCon architecture supports distributive processing, which can be critical for formation- control missions. AutoCon is completely object-oriented and can easily be enhanced by adding new objects and events. AutoCon-F was flight demonstrated onboard GSFC's EO-1 spacecraft flying in formation with Landsat-7.

Bristow, John↗
NASA NTRS1991

Galileo spacecraft autonomous attitude determination using a V-slit star scanner

The autonomous attitude determination system of Galileo spacecraft, consisting of a radiation hardened star scanner and a processing algorithm is presented. The algorithm applying to this system are the sequential star identification and attitude estimation. The star scanner model is reviewed in detail and the flight software parameters that must be updated frequently during flight, due to degradation of the scanner response and the star background change are identified.

Mobasser, Sohrab↗
NASA NTRS1991

Application of laser radar to autonomous spacecraft landing

This paper discusses the scenario of an autonomous landing like that required for the Mars Rover Sample Return Mission. An application of laser radar for conducting autonomous hazard detection and avoidance is discussed. A trade-study is performed to identify operational and implementation constraints as well as the state of the art in component technology.

Gleichman, Kurt↗
NASA NTRS1995

Semi-Autonomous Spacecraft On-Board Ephemeris Propagation

Two strategies are presented for semi-autonomous on-board trajectory propagation. One implements a semi-analytic method and rectifies, when needed, a simple on-board (on-line) ephemeris. The method is called rectification in which only several parameters are uplinked to the spacecraft infrequently. The other strategy uses TOPEX/POSEIDON experience to build a data compression device for a wide range of orbits. A trade-off study is conducted to relate accuracy requirements with semi-major axis and eccentricity to minimize the frequency of uplinking.

spacecraft↗