Severe space weather has the potential to cause significant socio‐economic impact and it is widely accepted that mitigating this risk requires more comprehensive observations of the Sun and heliosphere, enabling more accurate forecasting of significant events with longer lead‐times. In this context, it is now recognized that observations from the L5 Sun‐Earth Lagrange point (both remote and in situ) would offer considerable improvements in our ability to monitor and forecast space weather. Remote sensing from L5 allows for the observation of solar features earlier than at L1, providing early monitoring of active region development, as well as tracking of interplanetary coronal mass ejections through the inner heliosphere. In situ measurements at L5 characterize the solar wind's geoeffectiveness (particularly stream interaction regions), and can also be ingested into heliospheric models, improving their performance. The Vigil space weather mission is part of the ESA Space Safety Program and will provide a real‐time data stream for space weather services from L5 following its anticipated launch in the early 2030s. The interplanetary magnetic field is a key observational parameter, and here we describe the development of the Vigil magnetometer instrument for operational space weather monitoring at the L5 point. We summarize the baseline instrument capabilities, demonstrating how heritage from science missions has been leveraged to develop a low‐risk, high‐heritage instrument concept.

Strong natural hazards together with their societal impact are usually accompanied by multiple physical phenomena which can be an important information source about the underlying processes.  In this study we statistically analyze the lithosphere–atmosphere–ionosphere couplings of magnitude Mw5.5+ earthquakes (EQs) in the year 2023 with the aid of sub-ionospheric VLF/LF radio links. The electric field amplitude and phase measurements with a temporal resolution of one second are from the seismo-electromagnetic receiver facility in Graz (GRZ), Austria (Galopeau et al., 2023), which is part of the INFREP network. The spatial extend of the study area has the range [-10°E ≤ longitude ≤ 40°E] and [20°N ≤ latitude ≤ 50°N], in total are 17 EQs according to the United States Geological Survey (USGS) data base, among them the Turkey–Syria EQs (main shocks Mw7.8 and Mw7.5) and the Morocco Mw6.8 EQ. We apply the night-time amplitude method (Hayakawa et al., 2010) for all available paths, of particular importance are the transmitter links TBB (26.70 kHz, Bafa, Turkey), ITS (45.90 kHz, Niscemi, Sicily, Italy), and ICV (20.27 kHz, Tavolara, Italy). Relevant crossings are determined by the size of the Dobrovolsky-Bowman relationship (Dobrovolsky et al., 1979; Bowman et al., 1998).A major finding is the statistically significant electric field variation of the TBB-GRZ link related to the Turkey–Syria EQ sequence. A physical interpretation is based on atmospheric gravity waves (AGWs) which could alter the E-layer in the lower ionosphere during nighttime and modulate the height of the waveguide cavity.References:Galopeau et al., A VLF/LF facility network for preseismic electromagnetic investigations, Geosci. Instrum. Method. Data Syst., 12, 231–237, 2023, https://doi.org/10.5194/gi-12-231-2023Dobrovolsky et al., Estimation of the size of earthquake preparation zones, PAGEOPH 117, 1025–1044, 1979, https://doi.org/10.1007/BF00876083Bowman et al., An observational test of the critical earthquake concept, JGR Solid Earth, 103, B10, 24359-24372, 1998, https://doi.org/10.1029/98JB00792Hayakawa et al., A statistical study on the correlation between lower ionospheric perturbations as seen by subionospheric VLF/LF propagation and earthquakes, JGR Space Physics, 115(A9), 09305, 2010, https://doi.org/10.1029/2009JA015143

A set of optical fiber assemblies has been developed and successfully qualified for its use on a European space science mission to the icy moons of Jupiter (Jupiter Icy Moons Explorer, JUICE), to be launched in 2022. The paper gives an overview of the design challenges, the test methods used for failure detection and screening of the optical fiber cable assemblies as well as the further testing performed in the frame of a lot acceptance qualification.

Two types of multimode fibers (50μm and 400μm) are going to be used for the scalar sensor of the JUICE (Jupiter Icy Moon Explorer program) magnetometer. This optical sensor will be placed at the end of a boom and these multimode fibers will be used to transmit modulated laser light through the sensor, the light source and the detector electronics being located within the spaceship. The fibers will be exposed to very low temperatures while the optical connectors will be more protected. The simulation of the optical budget did not allow to assure that the optical power transmitted through the fibers would be OK within the entire thermal range. A 3-chambers thermal cycling test was proposed to thermally cycle in a synchronized way to different temperature plateaus, both high and low, while monitoring the transmitted optical power. Some pieces of fibers and mating connectors were stabilized to one temperature while others were at other values. The temperature ranges for each chamber were: -190ºC to 120ºC for one chamber, -160ºC to 100ºC for the second one and -80ºC to +45ºC for the third one. The light source used for the test was developed by the institute of experimental physics at TUG Graz using exactly the same lasers that will be used for JUICE. The stability of the setup was assured using a reference path. This paper presents the main challenges for this test and the results obtained.

We performed an endurance test with single-mode vertical-cavity surface-emitting lasers (VCSEL) under vacuum condition and increased operational parameters (laser current and laser temperature) to accelerate the aging of the lasers. During the endurance test the emitted polarization-dependent and polarization-independent optical light power from the lasers was detected. Additionally, electro-optical characterisations including measurements of the combination of laser current and laser temperature to excite the 87 Rb D 1 transition ( λ = 795 nm), the current and temperature tuning coefficients, laser line width, threshold current and the polarization ellipse were performed for the aged lasers. The test was started with a number of 12 VCSELs consisting of 4 lasers each from 3 different suppliers. The aging behaviour of VCSELs was investigated with respect to the development of a new optical magnetometer prototype for space missions with a mission duration of up to 17 years. Only a limited change of the electro-optical parameters can be tolerated by the instrument design over the mission duration. The endurance test and the electro-optical characterizations revealed clear differences in the aging behaviour of the three suppliers. Lasers from one supplier showed that they can be operated for more than 17 years under vacuum conditions without major degradation of their operational parameters.

Ten years after the successful landing of the Huygens Probe on the surface of Titan, we reassess the derivation of ground complex permittivity using the PWA-MIP/HASI measurements (Permittivity, Waves and Altimetry-Mutual Impedance Probe/Huygens Atmospheric Structure Instrument) at the frequencies 45, 90 and 360 Hz. For this purpose, we have developed a numerical method, namely "the capacity-influence matrix method", able to account for new insights on the Huygens Probe attitude at its final resting position. We find that the surface of Titan at the landing site has a dielectric constant of 2.5 +/- 0.3 and a conductivity of 1.2 +/- 0.6 nS/m, in agreement with previously published results but with much more reliable error estimates. These values speak in favour of a photochemical origin of the material in the first meter of the subsurface. We also propose, for the first time, a plausible explanation for the sudden change observed by PWA-MIP similar to 11 min after landing: this change corresponds to a drop in the ground conductivity, probably due to the removal of a superficial conductive layer in association with the release of volatile materials warmed by the Huygens Probe. (C) 2015 Elsevier Inc. All rights reserved.

From the institutes (1) Sorbonne Universites, UPMC Univ. Paris 06, LATMOS-IPSL, UMR 8190, 75005 Paris; (2) Universite Versailles St-Quentin; CNRS/INSU, LATMOS-IPSL, UMR 8190, 78280 Guyancourt; (3)European Space Agency, ESTEC, Noordwijk, The Netherlands. (4) LPC2E, CNRS, 3A Avenue de la Recherche Scientifique, F-45071 Orleans Cedex, France. (5) Space Research Institute, Austrian Acad. of Sciences (IWF), Schmiedlstrasse 6, 8042 Graz, Austria. (6) JHU/APL, Laurel,MD, United States (7) Instituto de Astrofisica de Andalucia (IAA), CSIC, P.O. Box 3004, E-18080 Granada, Spain. (8) Univ. Padova, Padova, Italy. (9) Royal Military College, Kingston, Ontario, Canada (10) G. Wattiaux, LAPLACE, Universite de Toulouse III.

Scalar magnetometers measure the magnitude of the magnetic field, while vector magnetometers (mostly fluxgate magnetometers) produce three-component outputs proportional to the magnitude and the direction of the magnetic field. While scalar magnetometers have a high accuracy, vector magnetometers suffer from parameter drifts and need to be calibrated during flight. In some cases, full science return can only be achieved by a combination of vector and scalar magnetometers.