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minimum. Clearly, the advantage of local stationarity diminishes as the temporal duration of the cycle increases. This is most
evident for a planetary mesh cycle, which can take several minutes to complete.
Author
Automatic Control; Time Dependence; Feedback Control; Dynamic Response; Helicopters; Vibration; Unsteady
Aerodynamics
20030025283 Aquilent, Inc., Laurel, MD, USA
Visualizing Decision-making Behaviours in Agent-based Autonomous Spacecraft
North, Steve; Hennessy, Joseph F., Technical Monitor; February 2003; 24 pp.; In English; No Copyright; Avail: CASI; A03,
Hardcopy
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.
Author
Autonomy; Decision Making; Information Analysis
20030025292 NASA Goddard Space Flight Center, Greenbelt, MD, USA
A Nonlinear, Six-Degree of Freedom Precision Formation Control Algorithm, Based on Restricted Three Body
Dynamics
Bauer, Frank, Technical Monitor; Luquette, Richard J.; Sanner, Robert M.; [2003]; 9 pp.; In English; AAS Guidance and
Control Conference, 5-9 Feb. 2003, Breckenridge, CO, USA
Report No.(s): AAS 03-007; Copyright; Avail: CASI; A02, Hardcopy
Precision Formation Flying is an enabling technology for a variety of proposed space-based observatories, including the
Micro-Arcsecond X-ray Imaging Mission (MAXIM), the associated MAXIM pathfinder mission, and the Stellar Imager. An
essential element of the technology is the control algorithm. This paper discusses the development of a nonlinear, six-degree
of freedom (6DOF) control algorithm for maintaining the relative position and attitude of a spacecraft within a formation. The
translation dynamics are based on the equations of motion for the restricted three body problem. The control law guarantees
the tracking error convergences to zero, based on a Lyapunov analysis. The simulation, modelled after the MAXIM Pathfinder
mission, maintains the relative position and attitude of a Follower spacecraft with respect to a Leader spacecraft, stationed near
the L2 libration point in the Sun-Earth system.
Author
Algorithms; Formation Flying; Nonlinearity; Three Body Problem; Degrees Of Freedom; Spacecraft Control
20030025748 NASA Goddard Space Flight Center, Greenbelt, MD, USA
Living with a Star Space Environment Testbed
Barth, Janet; January 2003; 5 pp.; In English; NATO Advanced Research Workshop on Effects of Space Weather on Tech.
Infrastructure; No Copyright; Avail: CASI; A01, Hardcopy
Summary of activities: (1) FYO1 NRA - Model development and data mining. (2) FY03 NRA - Flight investigations. (3)
SET carrier development. (4) Study for accommodation of SET carrier to support advanced detectors. (5) Collaboration with
other programs: LWS TR&T to maximize synergy between TR&T space environment research and SET space environment
effects research. LWS Data System to optimize dissemination of SET data. NASA Electronic Parts and Packaging Program
to leverage ground testing of technologies. Defense Threat Reduction Agency to leverage ground testing and common interests
in advanced detectors. and Air Force Research Laboratory to leverage flight opportunities. (6) Education and Public Outreach.
Derived from text
Models; Environment Effects; Data Mining; Aerospace Environments
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