T. Adrian Hill

Johns Hopkins University, Baltimore, Maryland, United States

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Publications (4)6.28 Total impact

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    ABSTRACT: The New Horizons spacecraft was launched on 19 January 2006. The spacecraft was designed to provide a platform for seven instruments that will collect and return data from Pluto in 2015. The design drew on heritage from previous missions developed at The Johns Hopkins University Applied Physics Laboratory (APL) and other missions such as Ulysses. The trajectory design imposed constraints on mass and structural strength to meet the high launch acceleration needed to reach the Pluto system prior to the year 2020. The spacecraft subsystems were designed to meet tight mass and power allocations, yet provide the necessary control and data handling finesse to support data collection and return when the one-way light time during the Pluto flyby is 4.5 hours. Missions to the outer solar system require a radioisotope thermoelectric generator (RTG) to supply electrical power, and a single RTG is used by New Horizons. To accommodate this constraint, the spacecraft electronics were designed to operate on less than 200 W. The spacecraft system architecture provides sufficient redundancy to provide a probability of mission success of greater than 0.85, even with a mission duration of over 10 years. The spacecraft is now on its way to Pluto, with an arrival date of 14 July 2015. Initial inflight tests have verified that the spacecraft will meet the design requirements. Comment: 33 pages, 13 figures, 4 tables; To appear in a special volume of Space Science Reviews on the New Horizons mission
    Preview · Article · Sep 2007 · Space Science Reviews
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    ABSTRACT: NASA's MESSENGER mission, part of its Discovery program, is the first mission to return to the planet Mercury since the Mariner 10 flybys in 1974 and 1975. The spacecraft incorporates many innovative features, including a sunshade made of ceramic cloth for protection from the Sun, a pair of electronically steerable phased-array antennas, and specially hardened solar panels. A suite of seven miniaturized science instruments, along with the antennas, will globally characterize the planet's composition, structure, atmosphere, and charged particle environment. MESSENGER was launched on August 3, 2004, and performed its single Earth flyby on August 2, 2005. The spacecraft will make two flybys of Venus and three of Mercury prior to orbiting the planet for one Earth-year beginning in March 2011. Highlights of a busy first year of flight operations include initial testing of all spacecraft systems and instruments, execution of six trajectory control maneuvers, and instrument observations of the Earth and Moon surrounding the August flyby
    Full-text · Conference Paper · Jan 2006
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    ABSTRACT: The MESSENGER spacecraft, the first mission to the planet Mercury since 1975, will achieve Mercury orbit in 2011. The spacecraft uses two opposite-facing mission-enabling X-band (8.4 GHz) phased-array antennas to achieve high-rate downlink communications. The spacecraft orientation is constrained such that a preferred direction faces the Sun; rotation about the Sun-line is allowable. The main beam of each antenna is steerable in one dimension. These two degrees of freedom allow the main beam of the phased array to be pointed in any direction about the spacecraft. A novel system-level design requires many different subsystems of the spacecraft to interact together to achieve accurate beam-pointing, and thus, high-rate downlink data from Mercury to Earth
    Preview · Conference Paper · Apr 2005
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    ABSTRACT: This paper describes a process of spacecraft flight software development that reuses requirements, designs, and implementations. Beginning in 1997, The Johns Hopkins University Applied Physics Laboratory (JHU/APL) developed the flight software for five different space missions: (1) Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED), (2) COmet Nucleus TOUR (CONTOUR), (3) MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER), (4) Solar TErrestrial RElations Observatory (STEREO), and (5) New Horizons, a mission to Pluto and beyond. JHU/APL met strict constraints of budget and schedule by reusing products from each mission for the following one in a successively more comprehensive fashion. Keys to the success of this reuse are consistent external interface protocols, rigorous requirements management, retention of the original development documentation, use of a consistent development process, and a group organization that fosters reuse. The reused packages include bootstrap, task scheduling, uplink, command handling, autonomy, and 1553 bus support.
    Preview · Article · Jan 2005