ARTEMIS Science Objectives

NASA??s two spacecraft ARTEMIS mission will address both heliospheric and planetary research questions, first while in orbit about the Earth with the Moon and subsequently while in orbit about the Moon. Heliospheric topics include the structure of the Earth??s magnetotail; reconnection, particle acceleration, and turbulence in the Earth??s magnetosphere, at the bow shock, and in the solar wind; and the formation and structure of the lunar wake. Planetary topics include the lunar exosphere and its relationship to the composition of the lunar surface, the effects of electric fields on dust in the exosphere, internal structure of the Moon, and the lunar crustal magnetic field. This paper describes the expected contributions of ARTEMIS to these baseline scientific objectives.     

The Galactic Environment of the Sun: Interstellar Material Inside and Outside of the Heliosphere

Interstellar material (ISMa) is observed both inside and outside of the heliosphere. Relating these diverse sets of ISMa data provides a richer understanding of both the interstellar medium and the heliosphere. The galactic environment of the Sun is dominated by warm, low-density, partially ionized interstellar material consisting of atoms and dust grains. The properties of the heliosphere are dependent on the pressure, composition, radiation field, ionization, and magnetic field of ambient ISMa. The very low-density interior of the Local Bubble, combined with an expanding superbubble shell associated with star formation in the Scorpius-Centaurus Association, dominate the properties of the local interstellar medium (LISM). Once the heliosphere boundaries and interaction mechanisms are understood, interstellar gas, dust, pickup ions, and anomalous cosmic rays inside of the heliosphere can be directly compared to ISMa outside of the heliosphere. Our understanding of ISMa at the Sun is further enriched when the circumheliospheric interstellar material is compared to observations of other nearby ISMa and the overall context of our galactic environment. The IBEX mission will map the interaction region between the heliosphere and ISMa, and improve the accuracy of comparisons between ISMa inside and outside the heliosphere.     

Simulation of conjugate heat transfer under conditions of aero-gas-dynamic heating of anisotropic blunt forebodies of hypersonic aircraft

An integrated physical and mathematical model of conjugate heat and mass transfer in super- and hypersonic flows around the blunt anisotropic bodies with determination of their thermal state is proposed. Also proposed is a technique for the numerical solution of the problems for conjugate heat exchange between gas-dynamic near-wall flows and bodies, the thermal conductivity of which is described by the second rank tensor. It is shown that variation of the tensor components of the material external layer thermal conductivity influences significantly the conjugation boundary temperature, which, in its turn, changes the heat flows to the body at the expense of temperature gradient at the conjugation boundary, density and dynamic viscosity.     

Correction to: Mission to Planet Earth: The First Two Billion Years

Space Science Reviews - The Ionospheric Connection Explorer (ICON) mission makes measurements in near-Earth space that provide knowledge of the state of the ionosphere. From the vantage of...     

Joint Ulysses and ACE observations of a magnetic cloud and the associated solar energetic particle event

On day 49 of 1999 a strong interplanetary shock was observed by the ACE spacecraft located at 1 AU from the Sun. This shock was followed 10 hours later by a magnetic cloud (MC). A large solar energetic particle (SEP) event was observed in association with the arrival of the shock and the MC at ACE. The Ulysses spacecraft, located at 22° S heliolatitude and nearly the same ecliptic longitude as ACE, observed a large SEP event beginning on day 54 that peaked with the arrival of a solar wind and magnetic field disturbance on day 61. A magnetic cloud was observed by Ulysses on days 63–64. We suggest a scenario in which both spacecraft intercepted the same MC, although sampling different regions of it. We describe the effects that the MC produced on the streaming of energetic particles at both spacecraft. This revised version was published online in August 2006 with corrections to the Cover Date.     

Oxygen and Iron Ions at High Heliolatitudes

The fluxes of O and Fe ions at high heliolatitudes measured by the HiScale instrument on Ulysses reflect the dynamical processes that affect the charged particle populations in the heliosphere. Both the O and Fe ions show more latitude dependence in the first (solar minimum) orbit to high southern heliolatitudes than during the second (solar maximum) orbit. The ion fluxes are larger during the solar minimum orbit; the flux levels are influenced by the occurrence of corotating interaction regions. The Fe/O abundance ratios are found to be similar at 1 AU and at high heliolatitudes. This revised version was published online in August 2006 with corrections to the Cover Date.     

High resolution 3D “snapshot” ISAR imaging and featureextraction

We have developed a new formulation for three dimensional (3D) radar imaging of inverse synthetic aperture radar (ISAR) data based on recent developments in high resolution spectral estimation theory. Typically for non real-time applications, image formation is a two step process consisting of motion determination and image generation. The technique presented focuses on this latter process, and assumes the motion of the target is known. The new technique offers several advantages over conventional techniques which are based on the correlation imaging function. In particular, the technique provides for a direct 3D estimate (versus back projection to a 3D target grid matrix) of the locations of the dominant scattering centers using only a minimum set of independent 2D range-Doppler ISAR “snapshots” of the target. Because of the snapshot nature of the technique, it is particularly applicable to 3D imaging of sectors of sparse-angle data, for which the sidelobes of the correlation imaging integral become high. Furthermore, the technique provides for an estimate of amplitude and phase of each scattering center as a function of aspect angle to the target, for those aspect angles which encompass the set of 2D range-Doppler snapshots. Results illustrating the technique developed are presented for both simulated and static range data     

Rosina – Rosetta Orbiter Spectrometer for Ion and Neutral Analysis

The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) will answer important questions posed by the mission’s main objectives. After Giotto, this will be the first time the volatile part of a comet will be analyzed in situ. This is a very important investigation, as comets, in contrast to meteorites, have maintained most of the volatiles of the solar nebula. To accomplish the very demanding objectives through all the different phases of the comet’s activity, ROSINA has unprecedented capabilities including very wide mass range (1 to >300 amu), very high mass resolution (m/Δ m > 3000, i.e. the ability to resolve CO from N₂ and ¹³C from ¹²CH), very wide dynamic range and high sensitivity, as well as the ability to determine cometary gas velocities, and temperature. ROSINA consists of two mass spectrometers for neutrals and primary ions with complementary capabilities and a pressure sensor. To ensure that absolute gas densities can be determined, each mass spectrometer carries a reservoir of a calibrated gas mixture allowing in-flight calibration. Furthermore, identical flight-spares of all three sensors will serve for detailed analysis of all relevant parameters, in particular the sensitivities for complex organic molecules and their fragmentation patterns in our electron bombardment ion sources.     

Improvement of a technological process for ceramic core removal out of internal cavities of aircraft GTE turbine blade castings

A technological process of removing a complex-shaped ceramic core from the interior of GTE thin-walled blade castings is considered. We propose an aluminium oxide-based method for removing a core by leaching accompanied by process intensification with a carboxylic acid additive.     

RPC-ICA: The Ion Composition Analyzer of the Rosetta Plasma Consortium

The Ion Composition Analyzer (ICA) is part of the Rosetta Plasma Consortium (RPC). ICA is designed to measure the three-dimensional distribution function of positive ions in order to study the interaction between the solar wind and cometary particles. The instrument has a mass resolution high enough to resolve the major species such as protons, helium, oxygen, molecular ions, and heavy ions characteristic of dusty plasma regions. ICA consists of an electrostatic acceptance angle filter, an electrostatic energy filter, and a magnetic momentum filter. Particles are detected using large diameter (100 mm) microchannel plates and a two-dimensional anode system. ICA has its own processor for data reduction/compression and formatting. The energy range of the instrument is from 25 eV to 40 keV and an angular field-of-view of 360° × 90° is achieved through electrostatic deflection of incoming particles.