Engineering topics
Publications and source records attributed to Roth, D..
During Cassini's third orbit around Saturn, the Huygens Probe was successfully released on a trjectory that resulted in the probe entering Titan's atmosphere on 14-January-2005, making it both the most distant spacecraft landing and the first spacecraft to successfully land on the moon of another planet.
This paper outlines the approach used to predict pointing uncertainty when pointing information is generated with a spacecraft prediction and older satellite ephemerides.
The Cassini spacecraft and its ground segment are currently testing a novel radio frequency multilink technology to perform radio science experiments.
In this paper the steps required to compute a "plasma free" observable are described and discussed in detail.
A new method using an array of MOS transistors formeasuring dose absorbed from ionizing radiation is compared to previous dosimetric methods., The accuracy and precision of dosimetry based on COTS SRAMs, DRAMs, and WPROMs are compared and contrasted. Applications of these devices in various space missions will be discussed. TID results are presented for this summary and microdosimetricresults will be added to the full paper. Finally, an analysis of the optimal condition for a digital dosimeter will be presented.
Most single grains in cadmium zinc telluride (CdZnTe) grown by the high-pressure Bridgman (HPB) technique contain multiple twin boundaries. As a consequence, twin boundaries are one of the most common macroscopic material defects found in large area (400 to 700 sq mm) CdZnTe specimens obtained from HPB ingots. Due to the prevalence of twin boundaries, understanding their effect on detector performance is key to the material selection process. Twin boundaries in several 2 mm thick large area specimens were first, documented using infrared transmission imaging. These specimens were then fabricated into either 2 mm pixel or planar detectors in order to examine the effect of the twin boundaries on detector performance. Preliminary results show that twin boundaries, which are decorated with tellurium inclusions, produce a reduction in detector efficiency and a degradation in resolution. The extent of the degradation appears to be a function of the density of tellurium inclusions.
The Cassini mission is designed to study the planet Saturn and its satellites, rings, and magnetosphere.
Study evaluates some nondestructive methods for characterizing ceramic-, metal-, and polymer-matrix composite materials. Results demonstrated utility of two ultrasonic methods for obtaining quantitative data on microstructural anomalies in composite materials.
This paper provides an in-depth review of the Mars Observer Navigation Team's activities throughout interplanetary cruise to Mars and our response to the spacecraft's anomaly which occurred approximately 68 hours before encounter.
The Mars Observer orbit determination activity extending from launch to loss of contact is summarized, and includes quantitative results and conclusions derived from mission experience.