Airglow in the Visible and Infrared Spectral Ranges of the Disturbed Upper Atmosphere under Conditions of High-Velocity Plasma Jet Injection: I. Experimental data

The measurements of infrared emission from an artificial structure, which was generated during the Fluxus experiment with plasma jet injection into the atmosphere, are obtained and discussed for the first time. Additional experimental data on the airglow in the visible spectral band of the disturbed region of the atmosphere are presented. A generalized analysis of the data is given.     

Magnetospheric Science Objectives of the <Emphasis Type="Italic">Juno</Emphasis> Mission

In July 2016, NASA’s Juno mission becomes the first spacecraft to enter polar orbit of Jupiter and venture deep into unexplored polar territories of the magnetosphere. Focusing on these polar regions, we review current understanding of the structure and dynamics of the magnetosphere and summarize the outstanding issues. The Juno mission profile involves (a) a several-week approach from the dawn side of Jupiter’s magnetosphere, with an orbit-insertion maneuver on July 6, 2016; (b) a 107-day capture orbit, also on the dawn flank; and (c) a series of thirty 11-day science orbits with the spacecraft flying over Jupiter’s poles and ducking under the radiation belts. We show how Juno’s view of the magnetosphere evolves over the year of science orbits. The Juno spacecraft carries a range of instruments that take particles and fields measurements, remote sensing observations of auroral emissions at UV, visible, IR and radio wavelengths, and detect microwave emission from Jupiter’s radiation belts. We summarize how these Juno measurements address issues of auroral processes, microphysical plasma physics, ionosphere-magnetosphere and satellite-magnetosphere coupling, sources and sinks of plasma, the radiation belts, and the dynamics of the outer magnetosphere. To reach Jupiter, the Juno spacecraft passed close to the Earth on October 9, 2013, gaining the necessary energy to get to Jupiter. The Earth flyby provided an opportunity to test Juno’s instrumentation as well as take scientific data in the terrestrial magnetosphere, in conjunction with ground-based and Earth-orbiting assets.     

Grain Surface Models and Data for Astrochemistry

The cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of \({\sim}25\) experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions.     

The Far Ultra-Violet Imager on the Icon Mission

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ionosphere. During sunlit atmospheric conditions, ICON FUV images the limb altitude profile in the shortwave (SW) band at 135.6 nm and the longwave (LW) band at 157 nm perpendicular to the satellite motion to retrieve the atmospheric O/N₂ ratio. In conditions of atmospheric darkness, ICON FUV measures the 135.6 nm recombination emission of \(\mathrm{O}^{+}\) ions used to compute the nighttime ionospheric altitude distribution. ICON Far UltraViolet (FUV) imager is a Czerny–Turner design Spectrographic Imager with two exit slits and corresponding back imager cameras that produce two independent images in separate wavelength bands on two detectors. All observations will be processed as limb altitude profiles. In addition, the ionospheric 135.6 nm data will be processed as longitude and latitude spatial maps to obtain images of ion distributions around regions of equatorial spread F. The ICON FUV optic axis is pointed 20 degrees below local horizontal and has a steering mirror that allows the field of view to be steered up to 30 degrees forward and aft, to keep the local magnetic meridian in the field of view. The detectors are micro channel plate (MCP) intensified FUV tubes with the phosphor fiber-optically coupled to Charge Coupled Devices (CCDs). The dual stack MCP-s amplify the photoelectron signals to overcome the CCD noise and the rapidly scanned frames are co-added to digitally create 12-second integrated images. Digital on-board signal processing is used to compensate for geometric distortion and satellite motion and to achieve data compression. The instrument was originally aligned in visible light by using a special grating and visible cameras. Final alignment, functional and environmental testing and calibration were performed in a large vacuum chamber with a UV source. The test and calibration program showed that ICON FUV meets its design requirements and is ready to be launched on the ICON spacecraft.     

The Juno Waves Investigation

Jupiter is the source of the strongest planetary radio emissions in the solar system. Variations in these emissions are symptomatic of the dynamics of Jupiter’s magnetosphere and some have been directly associated with Jupiter’s auroras. The strongest radio emissions are associated with Io’s interaction with Jupiter’s magnetic field. In addition, plasma waves are thought to play important roles in the acceleration of energetic particles in the magnetosphere, some of which impact Jupiter’s upper atmosphere generating the auroras. Since the exploration of Jupiter’s polar magnetosphere is a major objective of the Juno mission, it is appropriate that a radio and plasma wave investigation is included in Juno’s payload. This paper describes the Waves instrument and the science it is to pursue as part of the Juno mission.     

Geomagnetic Observations for Main Field Studies: From Ground to Space

Direct measurements of the geomagnetic field have been made for more than 400 years, beginning with individual determinations of the angle between geographic and magnetic North. This was followed by the start of continuous time series of full vector measurements at geomagnetic observatories and the beginning of geomagnetic repeat stations surveys in the 19th century. In the second half of the 20th century, true global coverage with geomagnetic field measurements was accomplished by magnetometer payloads on low-Earth-orbiting satellites. This article describes the procedures and instruments for magnetic field measurements on ground and in space and covers geomagnetic observatories, repeat stations, automatic observatories, satellites and historic observations. Special emphasis is laid on the global network of geomagnetic observatories.     

Active debris removal of multiple priority targets

Today’s space debris environment shows major concentrations of objects within distinct orbital regions for nearly all size regimes. The most critical region is found at orbital altitudes near 800 km with high declinations. Within this region many satellites are operated in so called sun-synchronous orbits (SSO). Among those, there are Earth observation, communication and weather satellites. Due to the orbital geometry in SSO, head-on encounters with relative velocities of about 15 km/s are most probable and would thus result in highly energetic collisions, which are often referred to as catastrophic collisions, leading to the complete fragmentation of the participating objects. So called feedback collisions can then be triggered by the newly generated fragments, thus leading to a further population increase in the affected orbital region. This effect is known as the Kessler syndrome.     

Buckling of composite panels: A criterion for optimum stiffener design

In this paper a linear, closed-form analysis of the buckling behavior of an orthotropic plate with elastic clamping and edge reinforcement under uniform compressive load is presented. This is a typical structural situation found in aerospace engineering for instance as stiffeners in wings or the fuselage. All governing equations are transformed in a dimensionless system using common characteristic quantities to gain good analytical access. The buckling behavior is analyzed and generic buckling diagrams are presented. The solutions show excellent agreement with results from literature and numerical analyses.The minimum bending stiffness of the edge reinforcement needed to withstand buckling is examined and a minimum stiffness criterion is presented. Furthermore an absolute minimum bending stiffness is found which is sufficient to enable the reinforcement to act as a near-rigid support for arbitrarily long plates. These criteria are of interest for optimized lightweight design of stringers and stiffeners.     

The International DORIS Service (IDS): Toward maturity

DORIS is one of the four space-geodetic techniques participating in the Global Geodetic Observing System (GGOS), particularly to maintain and disseminate the Terrestrial Reference Frame as determined by International Earth rotation and Reference frame Service (IERS). A few years ago, under the umbrella of the International Association of Geodesy, a DORIS International Service (IDS) was created in order to foster international cooperation and to provide new scientific products. This paper addresses the organizational aspects of the IDS and presents some recent DORIS scientific results. It is for the first time that, in preparation of the ITRF2008, seven Analysis Centers (AC’s) contributed to derive long-term time series of DORIS stations positions. These solutions were then combined into a homogeneous time series IDS-2 for which a precision of less than 10 mm was obtained. Orbit comparisons between the various AC’s showed an excellent agreement in the radial component, both for the SPOT satellites (e.g. 0.5–2.1 cm RMS for SPOT-2) and Envisat (0.9–2.1 cm RMS), using different software packages, models, corrections and analysis strategies. There is now a wide international participation within IDS that should lead to future improvements in DORIS analysis strategies and DORIS-derived geodetic products.     

Issues of geologically-focused situational awareness in robotic planetary missions: Lessons from an analogue mission at Mistastin Lake impact structure,Labrador, Canada

Remote robotic data provides different information than that obtained from immersion in the field. This significantly affects the geological situational awareness experienced by members of a mission control science team. In order to optimize science return from planetary robotic missions, these limitations must be understood and their effects mitigated to fully leverage the field experience of scientists at mission control.