Harold L. Hallock

Agent Technology from a NASA Perspective

NASAs drive toward realizing higher levels of autonomy, in both its ground and space systems, is supporting an active and growing interest in agent technology. This paper will address the expanding research in this exciting technology area. As examples of current work, the Lights-Out Ground Operations System (LOGOS), under prototyping at the Goddard Space Flight Center (GSFC), and the spacecraft-oriented Remote Agent project under development at the Ames Research Center (ARC) and the Jet Propulsion Laboratory (JPL) will be presented.

Control Laws: General Qualities

Your college years were probably your first exposure to the academic equivalent of ethnic humor, i.e., the jokes the various departments tell about their rival branches.

General Orbit Background

Unlike our first topic, attitude, orbit is a word for which most people probably could conjure up a reasonable visual image. They might envision the Earth and the other planets circling the Sun, or the Moon or a spacecraft circling the Earth.

Control Laws: Attitude Applications

There’s nothing that excites a scientist more than discovery of something new in nature. Sometimes, when the object or phenomenon is first predicted by theory and then observed later experimentally, it’s a cause for great celebration, at least among the proponents of the theory.

Spacecraft State Estimation More Broadly

There’s an old physics joke that compares the underlying philosophies of three major physics theories to attitudes (no pun intended) of three distinctly different baseball umpires.

Attitude Measurement Sensors

One of the original things about the Columbo television series was that you got to see the murderer commit a murder, and then got to watch Peter Falk try to learn what you already knew over the course of the rest of the program. Columbo would always go to the scene of the crime and view the carefully preserved murder site with his own eyes. Forensic staff, fully equipped with appropriate state-of-the-art investigative equipment, were there already collecting the on-site information he’d need to solve the crime, and he’d make his own unique, disruptive contributions to the process.

Attitude Conventions and Definitions

Most people who have had even the most casual contact with spacecraft (no, not a Close Encounter of the First Kind) have heard the term “orbit” used and have at least a rough idea of what the word means. By contrast, the first time you hear the phrase “attitude determination” or “attitude control” a whole host of rather exotic images may cross your mind, for example Michael Caine’s portrayal of Harry Palmer in the movie The Ipcress File. In some respects, these impressions are not totally far-fetched, and there are some similarities between psychiatry and spacecraft attitude control. Although the field of psychoanalysis is possessed of a rich literature documenting its knowledge and a host of psychoanalytical techniques for analyzing a subject have been established, it is difficult even for a talented psychiatrist to determine in the short-term a subject’s state of mind.

Onboard Attitude Determination

In the movie Magic Town, Jimmy Stewart plays a public opinion consultant who’s obsessed with finding a cheap, fast way to report how the American public feels about current events, issues, marketable products, election candidates (is that redundant?), etc. Not satisfied with traditional polling methods that canvass large numbers of people scattered across the United States, Stewart instead searches for a small town whose population is a perfect cross-section of the country.

Onboard Orbit Computations

In addition to reviving the classic “buddy picture” genre, as well as making Paul Newman and Robert Redford two of the top box office draws in Hollywood, Butch Cassidy and the Sundance Kid is particularly memorable for a long, drawn-out chase scene where ultimately nothing substantive happens.

Angular Momentum and Torque

During the 17th century, great physicists and mathematicians such as Descartes, Huygens, Newton, and Leibniz laid the foundations for our current classical understanding of translational motion, orbital motion, momentum, force, and energy, connecting to the physical world via the phenomena of mass and gravitation. But it wasn’t until Euler’s work in the middle of the 18th century that a formal description of general rotational motion was established.