Jean J. Lorre

The Near-Earth Asteroid Tracking (NEAT) Program: An Automated System for Telescope Control, Wide-Field Imaging, and Object Detection

The Near-Earth Asteroid Tracking (NEAT) system operates autonomously at the Maui Space Surveillance Site on the summit of the extinct Haleakala Volcano Crater, Hawaii. The program began in 1995 December and continues with an observing run every month. Its astrometric observations result in discoveries of near-Earth objects (NEOs), both asteroids (NEAs) and comets, and other unusual minor planets. Each six-night run NEAT covers about 10% of the accessible sky, detects thousands of asteroids, and detects two to five NEAs. NEAT has also contributed more than 1500 preliminary designations of minor planets and 26,000 detections of main-belt asteroids. This paper presents a description of the NEAT system and discusses its capabilities, including sky coverage, limiting magnitude, and detection efficiency. NEAT is an effective discoverer of NEAs larger than 1 km and is a major contributor to NASAs goal of identifying all NEAs of this size. An expansion of NEAT into a network of three similar systems would be capable of discovering 90% of the 1 km and larger NEAs within the next 10–40 yr, while serving the additional role of satellite detection and tracking for the US Air Force. Daily updates of NEAT results during operational periods can be found at JPLs Web site (http://huey.jpl.nasa.gov/~spravdo/neat.html). The images and information about the detected objects, including times of observation, positions, and magnitudes are made available via NASAs SkyMorph program.

The color of Mars: Spectrophotometric measurements at the Pathfinder landing site

We calculate the color of the Martian sky and surface directly using the absolute calibration of the Mars Pathfinder (MPF) lander camera, which was observed to be stable during the mission. The measured colors of the Martian sky and surface at the Pathfinder site are identical to the Viking sites, i.e., a predominantly yellowish brown color with only subtle variations. These colors are distributed continuously and fall into five overlapping groups with distinct average colors and unique spatial characteristics: shadowed soil, soil, soil/rock mixtures, rock, and sky. We report that the primary difference between the sky color and the color of the rocks is due to a difference in brightness. Measurements of the sky color show that the sky reddens away from the Sun and toward the horizon and that the sky color varies with time of day and is reddest at local noon. We present a true color picture of the Martian surface and color enhancement techniques that increase image saturation, maximize color discriminability while preserving hue, and eliminate brightness variations while preserving the chromaticity of the scene. Although Mars has long been called the “red” planet, quantitative measurements of the surface color from telescopic and surface observations indicate a light to moderate yellowish brown color. The Pathfinder camera measurements presented here support the claim that the red planet is not red but indeed yellowish brown.

Seeing in three dimensions: correlation and triangulation of Mars Exploration Rover imagery

The Mars Exploration Rovers (MER) uses a man-in-the-loop system for control in most cases. While capable of some autonomous driving, all arm operations and most drives are planned on the ground. Planning these operations requires a precise knowledge of the terrain surrounding of the rover: where are the rocks, the sand, and the hazards. This terrain is derived from images taken by stereoscopic cameras. This paper describes in detail the middle parts of the ground-based terrain derivation process: correlation, which finds matching points in the stereo pair, and triangulation, which converts those points to XYZ coordinates. The algorithms and free parameters are described, followed by a discussion of the results obtained, the problems encountered, and possible avenues for future development.

Processing and analysis of Mars Pathfinder science data at the Jet Propulsion Laboratory's Science Data Processing Systems Section

The Mars Pathfinder mission required new capabilities and adaptation of existing capabilities in order to support science analysis and flight operations requirements imposed by the in situ nature of the mission. The Science Data Processing Systems Section of the Jet Propulsion Laboratory was responsible for the design, development, and application of the system required to perform telemetry processing, distribution, and archiving of data from the four primary science instruments, and support of flight operations through production of automatically generated stereo and color mosaics, terrain visualizations, and animations. The system developed for Mars Pathfinder incorporated new capabilities in producing computer-generated color mosaics, for cataloging and distribution of science data, and utilized new display technology to support science analysis and flight operations requirements. This paper describes the data processing performed to support the science and operations payload on the Pathfinder lander and Sojourner rover.

Image Processing And Analysis Of Saturn's Rings

Processing of Voyager image data of Saturns rings at JPLs Image Processing Laboratory is described. A software system to navigate the flight images, facilitate feature tracking, and to project the rings has been developed. This system has been used to make measurements of ring radii and to measure the velocities of the spoke features in the B-Ring. A projected ring movie to study the development of these spoke features has been generated. Finally, processing to facilitate comparison of the photometric properties of Saturns rings at various phase angles is described.

Determination Of Planetary Photometric Functions

An essential step in the production of planetary mosaics and an important scientific experiment in its own right is the determination and removal of the photometric properties of the Atmosphere and surfaces of planetary objects. This paper reviews the work doen at the Image Processing Laboratory in this area in support of the Voyager Project.