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Publications (7)36.72 Total impact

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    ABSTRACT: The Cassini Plasma Spectrometer (CAPS) is one of twelve instruments on the Cassini-Huygens spacecraft. As the mission has progressed from launch, through Cruise, Tour, and Extended Mission, the level of automation within Operations and Data Processing has increased. As the Solstice Mission (2<sup>nd</sup> extended mission) has been approved, a move towards a final set of automated tools is in progress. This paper will address how automation has changed and what decisions were involved in the choice of the final set of automated tools to last through the Solstice Missions (into July 2017).
    Aerospace Conference, 2011 IEEE; 04/2011
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    ABSTRACT: Recently the Cassini CAPS team investigated the number of different software tools, programming languages, programs, and major technologies used in building and running its ground system. A total of twenty six different tools, programs, and major technologies were used in the downlink portion of the ground system and five different tools, programs, and major technologies are used for the uplink portion. This collection of tools, programs, and technologies were not considered in the initial ground system design at the beginning of operations, but were added as they were needed to address changing requirements. During the pre-launch phase of Cassini Huygens in 1997, operations were performed in a limited capacity in the calibration facilities. After launch, process automation increased gradually, as the ground system continued to grow. New technologies were incorporated as they emerged, and were added to the ground system, although they may not have been part of the initial plans. This led to some unexpected and sometimes creative inter-connectivity solutions to ensure that they could be integrated with the existing system. This paper will document the changes in the ground system from the period just before the first instrument check-out in January 1999 through the end of 2008. We will discuss why the technologies, programs, and tools were added. Lastly, we will look at the ground system from a management perspective in an attempt to determine how the system could have been built modularly, considering that emerging technologies and other capabilities could be added at a later date.
    Aerospace Conference, 2010 IEEE; 04/2010
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    ABSTRACT: Due to budget restrictions, the responsibility for operation of the science payload on the Cassini-Huygens mission is distributed across the science instrument teams. Under this distributed operations model, each instrument site is responsible for uplink operations instead of the large, centrally located operations facilities that are typical of spacecraft missions. Additionally, instrument teams are responsible for the standard downlink operations, science, and archiving. As long as requirements and deadlines are met, the Cassini project does not dictate how the requirements are met. Each instrument team was left on its own to come up with how they would respond to this challenge. This paper will chronicle the specifics of how distributed operations are coordinated and run within the Cassini Plasma Spectrometer (CAPS) operations team. By critically examining how operations have evolved over the 10 year period from late 1998 through the end of 2008, this paper will discuss lessons learned in operating this complex instrument. Additionally, current management techniques will be examined to determine if the efficiency of distributed operations can be improved.
    Aerospace Conference, 2010 IEEE; 04/2010
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    ABSTRACT: During Cassini's initial orbit, we observed a dynamic magnetosphere composed primarily of a complex mixture of water-derived atomic and molecular ions. We have identified four distinct regions characterized by differences in both bulk plasma properties and ion composition. Protons are the dominant species outside about 9 RS (where RS is the radial distance from the center of Saturn), whereas inside, the plasma consists primarily of a corotating comet-like mix of water-derived ions with approximately 3% N+. Over the A and B rings, we found an ionosphere in which O2+ and O+ are dominant, which suggests the possible existence of a layer of O2 gas similar to the atmospheres of Europa and Ganymede.
    Science 03/2005; 307(5713):1262-6. · 31.20 Impact Factor
  • AAS/Division for Planetary Sciences Meeting Abstracts #36; 11/2004
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    ABSTRACT: The Cassini Plasma Spectrometer (CAPS) will make comprehensive three-dimensional mass-resolved measurements of the full variety of plasma phenomena found in Saturn’s magnetosphere. Our fundamental scientific goals are to understand the nature of saturnian plasmas primarily their sources of ionization, and the means by which they are accelerated, transported, and lost. In so doing the CAPS investigation will contribute to understanding Saturn’s magnetosphere and its complex interactions with Titan, the icy satellites and rings, Saturn’s ionosphere and aurora, and the solar wind. Our design approach meets these goals by emphasizing two complementary types of measurements: high-time resolution velocity distributions of electrons and all major ion species; and lower-time resolution, high-mass resolution spectra of all ion species. The CAPS instrument is made up of three sensors: the Electron Spectrometer (ELS), the Ion Beam Spectrometer (IBS), and the Ion Mass Spectrometer (IMS). The ELS measures the velocity distribution of electrons from 0.6 eV to 28,250 keV, a range that permits coverage of thermal electrons found at Titan and near the ring plane as well as more energetic trapped electrons and auroral particles. The IBS measures ion velocity distributions with very high angular and energy resolution from 1 eV to 49,800 keV. It is specially designed to measure sharply defined ion beams expected in the solar wind at 9.5 AU, highly directional rammed ion fluxes encountered in Titan’s ionosphere, and anticipated field-aligned auroral fluxes. The IMS is designed to measure the composition of hot, diffuse magnetospheric plasmas and low-concentration ion species 1 eV to 50,280 eV with an atomic resolution M/ΔM ∼70 and, for certain molecules, (such asN 2 + and CO+), effective resolution as high as ∼2500. The three sensors are mounted on a motor-driven actuator that rotates the entire instrument over approximately one-half of the sky every 3 min.
    Space Science Reviews 01/2004; 114(1):1-112. · 5.52 Impact Factor
  • Bulletin of the American Astronomical Society. 01/2004; 36:4.