Engineering topics
Han, D.
Publications and source records attributed to Han, D..
Dawn Maneuver Design Performance at Vesta
The Dawn spacecraft orbited the asteroid Vesta from July 16, 2011 to September 5, 2012, successfully accomplishing the four planned science orbits and two planned rotational characterization orbits. The lowest-altitude science orbit lasted four months, with 20 planned orbit maintenance maneuvers. Navigation results from Vesta demonstrate that the navigation plan was sufficient to achieve orbit delivery accuracy requirements. This paper compares the flown Dawn trajectory against the planned trajectory and expected maneuver dispersions. Understanding the effectiveness of the Vesta maneuver design plan is a key component of planning for operations at Ceres, the next destination for the Dawn mission.
Doppler aided attitude determination for spin stabilized spacecraft
This paper describes the theory of spin signature removal and the results obtained during the Genesis and Contour missions, during which spin axis pointing measurement errors of 1 degree or less were achieved.
Navigating CONTOUR using the noncoherent transceiver technique
The objective of the CONTOUR mission was to conduct scientific fly-by studies of comets, Encke and Schwassmann-Wachmann 3, with the option of changing targets in-flight or visiting anadditional target after the SW3 encounter. The paper will describe the mission's planned trajectory, the navigation challenges, as well as the navigation tasks that were involved in achieving mission objectives.
Navigating CONTOUR using the noncoherent transceiver technique
The successful navigation of the Comet Nucleus Tour spacecraft was performed at JPL and was conducted with the use of the new noncoherent transceiver technique developed by the Applied Physics Laboratory. Discussions include the conditioning performed on the 2-way noncoherent Doppler data, the orbit determination process, and the post SRM trajectory reconstruction.
Sixth International Conference on Squeezed States and Uncertainty Relations
These proceedings contain contributions from about 200 participants to the 6th International Conference on Squeezed States and Uncertainty Relations (ICSSUR'99) held in Naples May 24-29, 1999, and organized jointly by the University of Naples "Federico II," the University of Maryland at College Park, and the Lebedev Institute, Moscow. This was the sixth of a series of very successful meetings started in 1990 at the College Park Campus of the University of Maryland. The other meetings in the series were held in Moscow (1992), Baltimore (1993), Taiyuan P.R.C. (1995) and Balatonfuered, Hungary (1997). The present one was held at the campus Monte Sant'Angelo of the University "Federico II" of Naples. The meeting sought to provide a forum for updating and reviewing a wide range of quantum optics disciplines, including device developments and applications, and related areas of quantum measurements and quantum noise. Over the years, the ICSSUR Conference evolved from a meeting on quantum measurement sector of quantum optics, to a wide range of quantum optics themes, including multifacet aspects of generation, measurement, and applications of nonclassical light (squeezed and Schrodinger cat radiation fields, etc.), and encompassing several related areas, ranging from quantum measurement to quantum noise. ICSSUR'99 brought together about 250 people active in the field of quantum optics, with special emphasis on nonclassical light sources and related areas. The Conference was organized in 8 Sections: Squeezed states and uncertainty relations; Harmonic oscillators and squeeze transformations; Methods of quantum interference and correlations; Quantum measurements; Generation and characterisation of non-classical light; Quantum noise; Quantum communication and information; and Quantum-like systems.
Decoherence Matrices
It is known that the Lorentz group is the natural language for a given two-beam system if there are no decoherence effects. This aspect of the twobeam system formulated in terms of the six-parameter representations of the Lorentz group. It is shown that these transformations do not alter the degree of coherence. Thus, the decoherence matrices do not come from the Lorentz group. It is shown therefore that a larger group is needed to accommodate the decoherence effects in the two-beam system. This larger group is isomorphic to O(3,3) or the Lorentz group with three space and three time dimensions.
Radio Navigation of Deep Space 1 During Ion Propulsion Usage
One of the main goals of the Deep Space 1 (DS1) project was to demonstrate the use of ion propulsion on an interplanetary spacecraft.
Using Autonomous Navigation for Interplanetary Missions: Mission Operations with Deep Space 1 Autonav
The first mission of NASA's New Millennium Program, Deep Space 1, has, as one of its principal demonstration-technologies, the first autonomous optical navigation system to be used in deep space.
Using Autonomous Navigation for Interplanetary Missions: The Validation of Deep Space 1 AutoNav
The first mission of NASA's New Millenium Program, Deep Space 1, has, as one of its principal demonstration technologies, the first autonomous optical navigation system to be used in deep space.
Overcoming Genesis Mission Design Challenges
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Deep Space 1 Autonomous Navigation
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Maneuver Design and Calibration for the Genesis Spacecraft
The Genesis is the fifth mission selected as part of NASA's Discovery Program.
Maneuver Design and Calibration for the Genesis Spacecraft
Genesis is the fifth mission selected as part of NASA's Discovery Program.
Genesis Mission Design
The Genesis spacecraft will collect solar wind samples from a halo orbit about the Sun-Earth L1 point for two years, returning those samples to Earth in 2003 for on-Earth analysis and examination.
Fifth International Conference on Squeezed States and Uncertainty Relations
The Fifth International Conference on Squeezed States and Uncertainty Relations was held at Balatonfured, Hungary, on 27-31 May 1997. This series was initiated in 1991 at the College Park Campus of the University of Maryland as the Workshop on Squeezed States and Uncertainty Relations. The scientific purpose of this series was to discuss squeezed states of light, but in recent years the scope is becoming broad enough to include studies of uncertainty relations and squeeze transformations in all branches of physics including quantum optics and foundations of quantum mechanics. Quantum optics will continue playing the pivotal role in the future, but the future meetings will include all branches of physics where squeeze transformations are basic. As the meeting attracted more participants and started covering more diversified subjects, the fourth meeting was called an international conference. The Fourth International Conference on Squeezed States and Uncertainty Relations was held in 1995 was hosted by Shanxi University in Taiyuan, China. The fifth meeting of this series, which was held at Balatonfured, Hungary, was also supported by the IUPAP. In 1999, the Sixth International Conference will be hosted by the University of Naples in 1999. The meeting will take place in Ravello near Naples.
Squeezed states as representations of symplectic groups
It is shown that the SU(1,1)-like and SU(2)-like two-photon coherent states can be combined to form a O(3,2)-like two-photon state. Since the O(3,2) group has many subgroups, there are also many new interesting new coherent and squeezed two-photon states. Among them is the two-photon sheared state whose symmetry property is like that for the two-dimensional Euclidean group. There are now two-phonon coherent states which may exhibit symmetries not yet observed for photons, including sheared states. Let us note that both SU(1,1) and S(3,2) are isomorphic to the symplectic groups Sp(2) and Sp(4) respectively, and that symplectic transformations consist of rotations and squeeze transformations.
Navigation for the new millennium: Autonomous navigation for Deep Space 1
The autonomous optical navigation system technology for the Deep Space 1 (DS1) mission is reported on. The DS1 navigation system will be the first to use autonomous navigation in deep space. The systems tasks are to: perform interplanetary cruise orbit determination using images of distant asteroids; control and maintain the orbit of the spacecraft with an ion propulsion system and conventional thrusters, and perform late knowledge updates of target position during close flybys in order to facilitate high quality data return from asteroid MaAuliffe and comet West-Kohoutek-Ikemura. To accomplish these tasks, the following functions are required: picture planning; image processing; dynamical modeling and integration; planetary ephemeris and star catalog handling; orbit determination; data filtering and estimation; maneuver estimation, and spacecraft ephemeris updating. These systems and functions are described and preliminary performance data are presented.