58 research outputs found

    Two Dual Ion Spectrometer Flight Units of the Fast Plasma Instrument Suite (FPI) for the Magnetospheric Multiscale Mission (MMS)

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    Two Dual Ion Spectrometer flight units of the Fast Plasma Instrument Suite (FPI) for the Magnetospheric Multiscale Mission (MMS) have returned to MSFC for flight testing. Anticipated to begin on June 30, tests will ensue in the Low Energy Electron and Ion Facility of the Heliophysics and Planetary Science Office (ZP13), managed by Dr. Victoria Coffey of the Natural Environments Branch of the Engineering Directorate (EV44). The MMS mission consists of four identical spacecraft, whose purpose is to study magnetic reconnection in the boundary regions of Earth's magnetosphere

    The Sun and Space Weather

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    Application of the NASCAP Spacecraft Simulation Tool to Investigate Electrodynamic Tether Current Collection in LEO

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    Recent interest in using electrodynamic tethers (EDTs) for orbital maneuvering in Low Earth Orbit (LEO) has prompted the development of the Marshall ElectroDynamic Tether Orbit Propagator (MEDTOP) model. The model is comprised of several modules which address various aspects of EDT propulsion, including calculation of state vectors using a standard orbit propagator (e.g., J2), an atmospheric drag model, realistic ionospheric and magnetic field models, space weather effects, and tether librations. The natural electromotive force (EMF) attained during a radially-aligned conductive tether results in electrons flowing down the tether and accumulating on the lower-altitude spacecraft. The energy that drives this EMF is sourced from the orbital energy of the system; thus, EDTs are often proposed as de-orbiting systems. However, when the current is reversed using satellite charged particle sources, then propulsion is possible. One of the most difficult challenges of the modeling effort is to ascertain the equivalent circuit between the spacecraft and the ionospheric plasma. The present study investigates the use of the NASA Charging Analyzer Program (NASCAP) to calculate currents to and from the tethered satellites and the ionospheric plasma. NASCAP is a sophisticated set of computational tools to model the surface charging of three-dimensional (3D) spacecraft surfaces in a time-varying space environment. The model's surface is tessellated into a collection of facets, and NASCAP calculates currents and potentials for each one. Additionally, NASCAP provides for the construction of one or more nested grids to calculate space potential and time-varying electric fields. This provides for the capability to track individual particles orbits, to model charged particle wakes, and to incorporate external charged particle sources. With this study, we have developed a model of calculating currents incident onto an electrodynamic tethered satellite system, and first results are shown here

    ANSMET 2013

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    From December 2013 to January 2014, MSFC Planetary Scientist Dr. Barbara Cohen participated in the Antarctic Search for Meteorites (ANSMET) 2013-2014 season. With a team of eight, a systematic search of the Antarctic ice in the South Miller Range turned up 333 samples; one of the largest is seen here with Dr. Cohen for scale. Since 1976, ANSMET has recovered more than 25,000 specimens from the ice along the Transantarctic Mountains. The icy surfaces of this area are particularly well suited for meteorite searches because of surface stranding: the surfaces must have bare ice, must be composed of large volumes, and the ice must flow out of the area more slowly than new ice arrives. The ANSMET specimens are currently the only reliable, continuous source of new, nonmicroscopic extraterrestrial material, and will continue to be until planetary sample-return missions are successful. The ANSMET program is supported by grants from the Solar System Exploration Division of NASA. Polar logistics are provided by the Office of Polar Programs of the U.S. National Science Foundation. The Principal Investigator of the current grant is Dr. Ralph P. Harvey at Case Western Reserve University. Dr. Barbara Cohen is seen with a large meteorite from the Antarctic's Miller Rang

    The Astronomy of Harry Potter

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    Implications of Extended Solar Minima

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    Since the discovery of periodicity in the solar cycle, the historical record of sunspot number has been carefully examined, attempting to make predictions about the next cycle. Much emphasis has been on predicting the maximum amplitude and length of the next cycle. Because current space-based and suborbital instruments are designed to study active phenomena, there is considerable interest in estimating the length and depth of the current minimum. We have developed criteria for the definition of a minimum and applied it to the historical sunspot record starting in 1749. In doing so, we find that 1) the current minimum is not yet unusually long and 2) there is no obvious way of predicting when, using our definition, the current minimum may end. However, by grouping the data into 22- year cycles there is an interesting pattern of extended minima that recurs every fourth or fifth 22-year cycle. A preliminary comparison of this pattern with other records, suggests the possibility of a correlation between extended minima and lower levels of solar irradiance

    The Sun and Eclipses: Will the Dragon Devour our Star?

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    Presentation for the Calera Elementary School STEM Night

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    Flows, Gusts, and Blasts from the Sun: the Nature of the Beast

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