The Coupled Dark State Magnetometer (CDSM) is an optically pumped magnetometer. For the Jupiter Icy Moons Explorer mission, the CDSM and two fluxgate magnetometers are combined in the J-MAG instrument to measure the static and low frequency magnetic field in the Jupiter system. During certain calibration manoeuvres, the CDSM has to be able to measure magnetic field strengths down to 100 nT with an accuracy of 0.2 nT ( 1 sigma). At such low magnetic fields, the CDSM's operational parameters must be carefully selected to obtain narrow resonance structures. Otherwise, the coupled dark state resonances, used for the magnetic field detection in different instrument modes, overlap and result in a systematic error. The overlap of the resonances and therefore the systematic error mainly depends on the resonance line width and the selected modulation frequencies for the detection of the resonances. We show that a line width of less than 200 Hz and selecting a modulation frequency of about the resonance line width are beneficial at magnetic field strengths B<1.5 mu T. In this paper we demonstrate that with the found instrument settings the CDSM is able to measure magnetic field strengths below 100 nT with a systematic error less than 0.2 nT resulting from the overlap of the resonances.

This paper discusses the accuracy of the scalar Coupled Dark State Magnetometer on board the Jupiter Icy Moons Explorer (JUICE) mission of the European Space Agency (ESA). The scalar magnetometer, referred to as MAGSCA, is part of the J-MAG instrument. MAGSCA is an optical omnidirectional scalar magnetometer based on coherent population trapping, a quantum interference effect, within the hyperfine manifold of the 87Rb D1 line. The measurement principle is only based on natural constants; therefore, it is in principle drift-free, and no calibration is required. However, the technical realisation can influence the measurement accuracy. The most dominating effects are heading characteristics, which are deviations of the magnetic field strength measurements from the ambient magnetic field strength. These deviations are a function of the angle between the sensor axis and the magnetic field vector and are an intrinsic physical property of the measurement principle of the magnetometer. The verification of the accuracy of the instrument is required to ensure its compliance with the performance requirement of 0.2 nT (1σ) with a data rate of 1 Hz. The verification is carried out with four dedicated sensor orientations in a Merritt coil system, which is located in the geomagnetic Conrad Observatory (COBS). The coil system is used to compensate the Earth's magnetic field and to apply appropriate test fields to the sensor. This paper presents a novel method to separate the heading characteristics of the instrument from residual (offset) fields within the coil system by fitting a mathematical model to the measured data and by the successful verification of the MAGSCA performance requirement.

A prototype of a Service Oriented Spacecraft Magnetometer (SOSMAG) is being developed for European Space Agency's Space Situational Awareness program, which shall serve as a ready-to-use space weather monitoring system to be mounted on a variety of different spacecraft built without a magnetic cleanliness program. The separation between the natural magnetic field in space and the artificial magnetic field generated by the spacecraft is one of the key issues for its successful performance. The SOSMAG design is based on two types of magnetic sensors. One or two low-noise fluxgate sensors for the required high measurement accuracy will be mounted along a boom of length 1 m, and two anisotropic magnetoresistance (AMR)-based sensors will be used within the spacecraft for detection and characterization of its magnetic disturbances. This paper presents the design and performance of the AMR magnetometer that contains an application-specified integrated circuit (ASIC) and a hybrid sensor as core elements. The magnetometer front-end ASIC, originally developed for National Aeronautics and Space Administration's Magnetospheric Multiscale mission, is based on a fourth-order sigma-delta A/D converter design. All the active electronics needed for the readout of the AMR sensor and its digitization, as well as for digitizing the magnetometer's housekeeping data are part of the ASIC. Each of the three-axis hybrid sensors consists of a ceramics circuit board with three HMC1021 sensor elements, one bypass capacitor, a temperature sensor, and a MOSFET driver mounted in chip-on-board technology. A novel approach is used to set and reset the AMR elements. It is done in a narrow-pulsed way at 32 kHz with a pulsewidth of only 238 ns, thus minimizing the required excitation power to 30 mW in total.

We present TID response up to 100 kRad(Si), of the three-axis vector magnetoresistive hybrid MAGIC, a low resource magnetometer integrated with a H-bridge drive on a co-fired ceramic chip.

We have developed a mission concept that uses 3-unit cubesats to perform new measurements of lunar magnetic fields, less than 100 meters above the Moon's surface. The mission calls for sending the cubesats on impact trajectories to strongly magnetic regions on the surface, and transmitting measurements in real-time to a nearby spacecraft, or directly to the Earth, up until milliseconds before impact. The cubesats and their instruments are partly based on the NSF-funded CINEMA cubesat now in Earth orbit. Two methods of reaching the Moon as a secondary payload are discussed: 1) After launching into geostationary transfer orbit with a communication satellite, a small mother-ship travels into lunar orbit and releases the cubesats on impact trajectories, and 2) The cubesats travel to the Moon using their own propulsion after release into geosynchronous orbit. This latter version would also enable other near-Earth missions, such as constellations for studying magnetospheric processes, and observations of close-approaching asteroids.

Planetary plasma and magnetic field environments can be studied in two complementary ways—by in situ measurements, or by remote sensing. While the former provide precise information about plasma behaviour, instabilities and dynamics on local scales, the latter offers the global view necessary to understand the overall interaction of the magnetospheric plasma with the solar wind. Some parts of the Earth’s magnetosphere have been remotely sensed, but the majority remains unexplored by this type of measurements. Here we propose a novel and more elegant approach employing remote X-ray imaging techniques, which are now possible thanks to the relatively recent discovery of solar wind charge exchange X-ray emissions in the vicinity of the Earth’s magnetosphere. In this article we describe how an appropriately designed and located X-ray telescope, supported by simultaneous in situ measurements of the solar wind, can be used to image the dayside magnetosphere, magnetosheath and bow shock, with a temporal and spatial resolution sufficient to address several key outstanding questions concerning how the solar wind interacts with the Earth’s magnetosphere on a global level. Global images of the dayside magnetospheric boundaries require vantage points well outside the magnetosphere. Our studies have led us to propose ‘AXIOM: Advanced X-ray Imaging of the Magnetosphere’, a concept mission using a Vega launcher with a LISA Pathfinder-type Propulsion Module to place the spacecraft in a Lissajous orbit around the Earth–Moon L1 point. The model payload consists of an X-ray Wide Field Imager, capable of both imaging and spectroscopy, and an in situ plasma and magnetic field measurement package. This package comprises a Proton-Alpha Sensor, designed to measure the bulk properties of the solar wind, an Ion Composition Analyser, to characterise the minor ion populations in the solar wind that cause charge exchange emission, and a Magnetometer, designed to measure the strength and direction of the solar wind magnetic field. We also show simulations that demonstrate how the proposed X-ray telescope design is capable of imaging the predicted emission from the dayside magnetosphere with the sensitivity and cadence required to achieve the science goals of the mission.