The paper covers the principal requirements, design concepts and implementation of the hardware and software for the central on-board computer (CDMS) of the Philae lander in the context of the ESA Rosetta space mission, including some technical details. The focus is on the implementation of fault tolerance, autonomous operation and operational flexibility by means of specific linked data structures and code execution mechanisms that can be interpreted as a kind of object oriented model for mission sequencing. (C) 2015 IAA. Published by Elsevier Ltd. All rights reserved.

The Rosetta-Philae space mission is an unprecedented venture. After a ten-year journey across the Solar System and many complicated manoeuvres, the Rosetta spacecraft smoothly approached a small (2-4 km in diameter) celestial body, comet CG/67P. Furthermore, the spacecraft executed additional fine manoeuvres to fly a multitude of low and high altitude orbits around the comet, mapping its shape and surface in detail never seen before, and has continued to observe it for a year since then. The Rosetta spacecraft is equipped with scientific instruments that deliver a wealth of new knowledge about the CG/67P comet, in addition to spectacular pictures. Delivering the Philae lander onto the surface of the comet 500 million km away from Earth was also a remarkable technological success. The direct measurements made by the Philae lander on the surface of the comet provided significant new knowledge. The first half of this paper gives a brief overview of the objectives and highlights of the Rosetta-Philae mission. In the second half the major hardware and software design aspects, including the conceptual design and implementation of the central on-board computer (CDMS) of the Philae lander are outlined. It focuses on the implementation of fault tolerance, autonomous operation and operational flexibility by means of specific linked data structures and code execution mechanisms that can be interpreted as a kind of object oriented model for mission sequencing.

This chapter contains sections titled: Introduction Magnetospheric Boundary Crossings in the Cusp Vicinity on April 21, 1996 The Phenomenon Scale Studies Statistical Review Discussion and Conclusions

This chapter contains sections titled: Introduction Three-Dimensional Resistive MHD Simulations of Magnetotail Reconnection Three-Dimensional Kinetic Simulations of Reconnection Observations Discussion and Summary

The scientific objectives, design and capabilities of the Rosetta Lander’s ROMAP instrument are presented. ROMAP’s main scientific goals are longterm magnetic field and plasma measurements of the surface of Comet 67P/Churyumov-Gerasimenko in order to study cometary activity as a function of heliocentric distance, and measurements during the Lander’s descent to investigate the structure of the comet’s remanent magnetisation. The ROMAP fluxgate magnetometer, electrostatic analyser and Faraday cup measure the magnetic field from 0 to 32 Hz, ions of up to 8000 keV and electrons of up to 4200 keV. Additional two types of pressure sensors – Penning and Minipirani – cover a pressure range from 10 −8 to 10 1 mbar. ROMAP’s sensors and electronics are highly integrated, as required by a combined field/plasma instrument with less than 1 W power consumption and 1 kg mass.

The magnetometric system of the СПРУТ-VI instrument package installed on board the Mir orbital station in 1999 is described. The system was a fluxgate magnetometer that enabled high-precwasion vector measurements (with a resolution of 0.1 nT for each component) of the magnetic field over a range of ±65 000 nT. The operating temperature range of the sensing device was –170 to +80°C and the temperature range of the system electronics was –55 to +60°C. The system was used for studying fluctuations of the Earth's magnetic field and characteristics of various particle formations in near-equatorial and low latitudes as well as calculating the pitch-angle distribution of fluxes of charged particles and determining the exact spatial coordinates of isolated malfunctions in microcircuits.

Magnetic field measurements in solar wind and outer magnetosphere onboard the INTERBALL-1 spacecraft were performed by the following magnetometers: MIF-M magnetometer with both DC sensor (BPP) having 0.2 nT threshold sensitivity at DC and 5 pT at 1 Hz and AC sensor (DM2) with the sensitivity about 0.2 nT at 1 Hz and 0.4 pT at 100 Hz; FGM-I DC magnetometer with threshold sensitivity of 5 pT at 1 Hz; FM-31 DC magnetometer with two sensors having 0.1 nT (sensor MI) and 1.0 nT (sensor M2) threshold sensitivity. During INTERBALL-1 operation the ionosphere experiment SPRUT-VI onboard the MIR station was performed from 06/13–08/26/1999. The measurements of DC magnetic field, electron and ion fluxes at energies between 50 keV–2.5 MeV and 50 keV–30 MeV were made. The SPRUT-MAG digital magnetometer for this experiment is based on the one developed for the ESA Rosetta Lander device ROMAP which threshold sensitivity was about 5 pT/(Hz)1/2 at 1 Hz. This paper discusses the possibility of signals processing with the aim to separate the artificial (technical, connected with the MIR onboard system operation) and natural origin signals as well as to estimate the level of ULF/ELF magnetic field disturbances and particle flows bursts.

A detailed analysis of the disturbances of a magnetic field near Phobos was carried out. Two types of force lines were found. Some of them correspond to the force lines of the solar wind disturbed by an obstacle. The others are related to Phobos. The character and the direction of the disturbances give strong evidence for the existence of the Phobos magnetic field and magnetosphere. Assuming the dipole approximation, the value of magnetic field of Phobos at its surface is 0.6 G. It is comparable to the magnetic field at the surface of the Earth.

A new phenomenon was discovered on the basis of analysis of the Interball project data. A hot plasma flow is thermalized through the formation of “long-operating” vortex streets and local discontinuities and solitons in a distributed region over polar cusps. Plasma percolation through the structured boundary and secondary reconnection of fluctuating magnetic fields in a high-latitude turbulent boundary layer account for the main part of solar wind plasma inflow into the magnetospheric trap. Unlike local shocks, the ion thermalization is accompanied by the generation of coherent Alfvén waves on the scales ranging from ion gyroradius to the radius of curvature of the averaged magnetic field, as well as by the generation of diamagnetic bubbles with a demagnetized heated plasma inside. This “boiling” plasma has a frequency region where the spectrum is different from the Kolmogorov law (with slopes 1.2 and 2.4 instead of 5/3 or 3/2). The fluctuation self-organization in the boundary layer (synchronization of three-wave decays) was observed on certain frequency scales.

The interaction of Phobos with the solar wind is considered both theoretically and using the experimental data of the FGMM magnetometer that were obtained in the course of the Phobos-2mission. It is demonstrated that the ions serving as a source of excitation of magnetosonic waves can be accumulated around Phobos. Examination of the magnetometer data has shown that the observed effects of a local decrease of the magnetic field near the Phobos orbit correspond to magnetosonic waves. Observation of these effects depends on the geometry of an experiment.

The magnetometer onboard the Equator-S satellite is very sensitive and has a high sampling rate of up to 128 Hz. These specifications allow for the first fluxgate magnetometer measurements of ELF waves between the ion cyclotron and the lower hybrid frequencies in the equatorial dayside magnetosheath. The so-called lion roars, typically seen by the Equator-S magnetometer at the bottom of the magnetic troughs of magnetosheath mirror waves, are near-monochromatic packets of electron whistler waves lasting for 0.2–1 sec. They are right-hand circularly polarized shear waves with typical amplitudes of 0.5–1 nT at frequencies of 15–40 Hz, i.e., around one tenth of the electron gyrofrequency.

The special feature of the ringcore ̄uxgate magnetometer on Equator-S is the high time and ®eld resolution. The scienti®c aim of the experiment is the investigation of waves in the 10±100 picotesla range with a time resolution up to 64 Hz. The instrument characteristics and the in ̄uence of the spacecraft on the magnetic ®eld measurement will be discussed. The work shows that the applied preand in ̄ight calibration techniques are sucient to suppress spacecraft interferences. The o€set in spin axis direction was determined for the ®rst time with an independent ®eld measurement by the Equator-S Electron Drift Instrument. The data presented gives an impression of the accuracy of the measurement.

The special feature of the ringcore fluxgate magnetometer on Equator-S is the high time and field resolution. The scientific aim of the experiment is the investigation of waves in the 10–100 picotesla range with a time resolution up to 64 Hz. The instrument characteristics and the influence of the spacecraft on the magnetic field measurement will be discussed. The work shows that the applied pre- and inflight calibration techniques are sufficient to suppress spacecraft interferences. The offset in spin axis direction was determined for the first time with an independent field measurement by the Equator-S Electron Drift Instrument. The data presented gives an impression of the accuracy of the measurement.

The magnetometer onboard the Equator-S satellite is very sensitive and has a high sampling rate of up to 128 Hz. These specifications allow for the first fluxgate magnetometer measurements of ELF waves between the ion cyclotron and the lower hybrid frequencies in the equatorial dayside magnetosheath. The so-called lion roars, typically seen by the Equator-S magnetometer at the bottom of the magnetic troughs of magnetosheath mirror waves, are near-monochromatic packets of electron whistler waves lasting for 0.2–1 sec. They are right-hand circularly polarized shear waves with typical amplitudes of 0.5–1 nT at frequencies of 15–40 Hz, i.e., around one tenth of the electron gyrofrequency.

We use magnetic field observations by the fluxgate magnetometer FGM-I during two substorm related INTERBALL-1 plasma sheet encounters to discuss signatures of reconnection in the Earth's magnetotail. In the first case the satellite stayed northward of the current sheet; in the second case for most of the substorm time it stayed in the northern lobes until it approached the plasma sheet and, finally, crossed the current sheet. In order to determine whether the observed magnetic field signatures can be understood in the framework of a resistive magnetohydrodynamic (MHD) approach to reconnection, we generated data using a three-dimensional numerical MHD model of the tail. In the model, reconnection takes place due to a localized finite resistivity. Comparing the modeled data with the measured ones, we find that, although the substorm-related dipolarization-like evolution of the Bx and the Bz field components can be well understood in terms of a resistive MHD approach to reconnection with dipolarization starting before the substorm ground onset and geostationary injection tailward of the satellite position, all attempts failed to explain the observed transient dawnward drop of the shear component By by a resistive MHD model of three-dimensional reconnection. We conclude that the dawnward drop has to be caused by effects beyond the resistive MHD approach.

We analyze the highly variable magnetic field behavior after a high-latitude outbound boundary layer crossing of the INTERBALL-1 main satellite on August 26, 1995, using data obtained by the fluxgate magnetometer FGM-1. We suggest that the oscillations, observed immediately after the first magnetopause crossing, are due to a Kelvin-Helmholtz instability. We verify this suggestion by appropriate MHD simulations. For the sake of a direct comparison we present the simulation results in a frame moving through the propagating structure at the relative speed of the satellite along its orbit. As a result we have found that the observed signatures compare well with the simulated crossing of a Kelvin-Helmholtz unstable magnetopause.

The first model of a three component fluxgate magnetometer based on a near sensor digitization of the fluxgate signals (digital fluxgate magnetometer) will be presented. High flexibility as well as low power and weight requirements are the main arguments to qualify the digital magnetometer for planetary missions. Tests have shown that the low noise level and long term stability of the reduced electronics and the described algorithm are good enough, so that only the sensor noise and stability limits the accuracy of the magnetometer.

The plasma-wave experiment ASPI (analysis of spectra of plasma waves and instabilities) on board the INTERBALL spacecraft is a combined wave diagnostics experiment. It performs measurements of the DC and AC magnetic field vector by flux-gate and search-coil sensors, the DC and AC electric field vector by Langmuir double probes and the plasma current by Langmuir split probe. Preliminary data analysis shows the low noise levels of the sensors and the compatibility of new data with the results of previous missions. During several months of in-orbit operation a rich collection of data was acquired, examples of which at the magnetopause and plasma sheet are presented in second part of the paper.

We present two examples of INTERBALL-1 data near both the high and low-latitude tail magnetopause (MP) under disturbed conditions. For the high-latitude case, MAGION-4 data determine the scales of the MP current sheets which are in the order of 100–500 km for the main ones, 50–200 km for Flux Transfer Events (FTEs) and a few km for the fine structures and ULF turbulence. The MP speed was 15–30 km/s. The energetic protons in the magnetosheath (MSH) provide evidence of reconnection upstream of the spacecraft (S/C). The tailward flows grow for the northward MSH magnetic field when the reconnection site is believed to be shifted tailward of the cusp. The inner boundary layer (BL) after the disturbance consists of tailward and earthward flowing plasma of MSH origin and cold mantle plasma flowing tailward The earthward flow is evidence of reconnection tailward of the S/C, which is regarded as a specific feature of the disturbed conditions. Local production of a plasma-sheet-like plasma at high latitudes is argued based on the inner BL plasma characteristics. The following features are observed in both cases: (a) FTEs for both northward and southward MSH fields; (b) waves in the current sheet vicinities over ten mV/m and 15 nT peak-to-peak; (c) electron fluxes with scales down to a few km with extra heating especially parallel to the magnetic field; (d) outer turbulent boundary layers with a deflected magnetic field; (e) ions with time-energy dispersion-like features and deflected ion fluxes. In the downstream dawn region at the transition between the low-latitude boundary layer and the plasma sheet (LLBL/PS), multiple MP encounters are observed. In the LLBL parallel electron intensifications correlate with ULF magnetic fluctuations.

The Space Research Institute of the Austrian Academy, of Sciences (Graz, Austria) in cooperation with MPE (Berlin, Germany), GFZ Potsdam (Obs. Niemegk, Germany) IZMIRAN/IOFAN (Moscow, Russian) and IGPP/UCLA (Los Angeles, USA) is designing the magnetic field experiment MAGIBAL (MAGnetic field experiment aboard a martian BALloon) to investigate the magnetic field on the surface of Mars. The dual sensor fluxgate magnetometer is part of the MARS-98/ MARS-TOGETHER balloon payload. During a ten days period the balloon will float over a distance of about 2000 km at altitudes between 0 and 4 km. Due to the limited power and telemetry allocation the magnetometer can transmit only one vector per ten seconds and spectral information in the frequency range from 2 - 25 Hz. The dynamic range is +/- 2000 nT.The main scientific objectives of the experiment are:Determination of the magnetism of the Martian rocksInvestigation of the leakage of the solar wind induced magnetosphere using the correlation between orbiter and balloon observationsMeasurement of the magnetic field profile between the orbiter and the surface of Mars during the descent phase of the balloon.Terrestrial test flights with a hot air balloon were performed in order to test the original MAGIBAL equipment under balloon flight conditions.