The BepiColombo Laser Altimeter (BELA) is the first European laser altimeter constructed for interplanetary flight. BELA uses a 50 mJ pulsed Nd:YAG laser operating at 10 Hz with a 20 cm aperture receiver to perform the ranging. The instrument also uses a digital approach for range detection and pulse analysis. The ranging accuracy is expected to be better than 2 metres and ∼20 cm in optimum conditions. With the given, only slightly elliptical, orbit, BELA should return a consistent data set for the most if not all of the planet. The instrument is required to function in an extreme environment with the thermal issues being particularly demanding. Novel solutions have been taken to resolve these issues. BELA is described in detail and its predicted performance outlined on the basis of pre-flight testing.

This paper reports on EMC issues of the laser transmitter, the photodiode receiver, and the communication port of the BepiColombo Laser Altimeter BELA during integration on ESA's Mercury Planetary Orbiter MPO. Parasitic currents originating in the active Q-switch electronics of BELA's diode-laser pumped Nd:YAG laser and from the high-power laser diode driver electronics interfered with the sensitive Si avalanche photodiode sensor operating at a noise floor of about 0.3 pA/VHz in a bandwidth of 20 MHz, and with BELA's Spacewire port, corrupting about 3% of telemetry data to the MPO memory. The problems had been eliminated by implementing multi-point grounding.

Planetary geology, in-situ exploration, cartography, 3D and spectral imaging plus navigation are strong coupled with the application of imaging systems based on CCDs and modern scientific CMOS (sCMOS) optical sensors. The development of such imaging systems requires high performance detectors, radiation tolerant IEEE circuits combined with a space qualified optical system on the input and a powerful digital processor unit on the output side.

The detailed investigation of three of Jupiter‘s Galilean satellites (Ganymede, Europa, and Callisto), which are believed to harbour subsurface water oceans, is central to elucidating the conditions for habitability of icy worlds in planetary systems. The study of the Jupiter system and the possible existence of habitable environments offer the best opportunity for understanding the origins and formation of the gas giants and their satellite systems. The JUpiter ICy moons Explorer (JUICE) camera system JANUS (Jovis, Amorum ac Natorum Undique Scrutator) will determine the formation and characteristics of magmatic, tectonic, and impact features, relate them to surface forming processes, constrain global and regional surface ages, and investigate the processes of erosion and deposition. Global medium resolution imaging of Ganymede and important parts of the surface of Callisto better than 400 m/pixel (resolution limited by mission data volume) will provide context information. Selected targets will be investigated with high-resolution imaging with spatial resolution from 25 m/pixel down to 3 m/pixel. The camera system has 13 panchromatic, broadand narrow-band filters in the 0.36 μm to 1.1 μm range, and provides stereo imaging capabilities. JANUS will also allow relating spectral, laser and radar measurements to geomorphology and thus will provide the overall geological context. Introduction: The Galilean satellites Io, Europa, Ganymede and Callisto show an increase in geologic activity with decreasing distance to Jupiter [e.g. 1]. Io, nearest to Jupiter, is volcanically active. Europa could still be tectonically and volcanically active today, while Callisto, the outermost Galilean satellite, is geologically inactive. Ganymede holds a key position in the Jovian satellite system in terms of geologic evolution because it features old, densely-cratered terrain, like most of Callisto, but also widespread tectonically resurfaced regions, similar to most of the surface of Europa. Investigating Ganymede, the largest satellite in the solar system, from an orbiter is essential because of (1) its wide range of surface ages which reveals a geologic record of several billions of years, (2) its great variety in geologic and geomorphic units, (3) its active magnetic dynamo, and (4) the possible presence of a subsurface ocean. The three icy Galilean satellites Callisto, Ganymede and Europa show a tremendous diversity of surface features and differ significantly in their specific evolutionary paths. Each of these moons exhibits its own fascinating geologic history – formed by competition and also combination of external and internal processes. Their origins and evolutions are influenced by factors such as density, temperature, composition (volatile compounds), stage of differentiation, volcanism, tectonism, the rheological reaction of ice and salts to stress, tidal effects, and interactions with the Jovian magnetosphere and space. These interactions are still recorded in the present surface geology. The record of geological processes spans from possible cryovolcanism through widespread tectonism to surface degradation and impact cratering. The huge scientific return of JANUS is not only based on the geology of the Galilean satellites, that in any case represent the driving case for the design, but also on the observation of the Jupiter atmosphere and the satellite exospheres, using specific filters, the Jupiter rings and the minor satellites for astrometric purposes and on the contribution in the determination of the rotational status of Ganymede, to constrain its internal structure. The JANUS Experiment Outstanding questions that will be addressed by JUICE Imaging [2]: What are the relative roles of EPSC Abstracts Vol. 8, EPSC2013-506, 2013 European Planetary Science Congress 2013 c © Author(s) 2013 EPSC European Planetary Science Congress tectonism and cryovolcanism in shaping the dark and bright terrains on Ganymede? What does the distribution of craters on the Galilean satellites tells us about the evolution of the impactor population in the Jovian system through time? How is the geological evolution of Ganymede and Europa related to the impact, tectonic and cryovolcanic history and how is the geological evolution correlated with differentiation processes and stages? What are the ages of specific geological units on Ganymede and Europa, and how will these findings contribute to our understanding of the origin and evolution of the Jupiter system? What is the rheological response of ices and ice/salt/clathrate mixtures w.r.t. tectonic stress? To what extent are surfaces altered by cosmic weathering and what are the major exogenic surface alteration processes (micrometeorites, radiation, charged particles)? What are the fine-scale characteristics of non-ice materials on Callisto? By which intriguing mechanisms is CO2-replenishment taking place on Callisto? Performance of the Instrument Required to Fulfil the Anticipated Goals: JANUS is the next logical step after the impressive successes of the imaging studies by Voyager, Galileo and Cassini of the Jovian system. JANUS will allow orders-ofmagnitude steps ahead in terms of coverage and/or resolution and/or time evolution on many targets in Jupiter system. JANUS spatial resolution ranges from 400 m/pixel to 100 can be maintained in almost all observational scenarios. Figure 1: Ground Resolution and surface coverage for Ganymede by JANUS compared to Galileo. Instrument Design: The JANUS camera consists of three units with physical I/F with JUICE: a) the optical head including the telescope and mounting structure, the filter wheels and the focal plane; b) the proximity electronics; c) the main electronics including camera control, data handling, compression and power supply. The following architectural design was developed: a catadioptric telescope with excellent optical quality is coupled with a framing detector, avoiding any scanning mechanism and, above all, any operational requirement on the S/C. The JANUS design is tuned to have the highest probability to guarantee a great scientific success to the mission by the best usage of the resources allocated on imaging by JUICE through the implementation of a single NAC channel, with WAC capabilities, with high reliability due to the redundancy philosophy. Our proposal has also the advantage to obtain the low to medium resolution Ganymede global coverage earlier during the mission, allowing better choice of observation targets for the high-resolution phase. References: [1] Stephan, K., R. Jaumann, and R. Wagner. 2013. Geology of Icy Bodies. In: The Science of Solar System Ices, edited by M. S. Gutipati and J. Castillo-Rogez. Astrophys. and Space Sci. Libr. 356, p. 279 – 367, Springer Science+Business Media, New York, USA. [2] Grasset, O., et al., 2013. JUpiter ICy moons Explorer (JUICE): an ESA mission to orbit Ganymede and to characterise the Jupiter system, Planet. and Space Sci 78, 121, doi.org/10.1016/j.pss.2012.12.002.

CCD front end electronics for GAIA mission. Design, development and test of the CCD electronics and interconnection module. Presentation of the opto-electrical performance and design hints for flight development phase.

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 feasibility and first results of a near sensor digitalization of fluxgate signals (digital fluxgate magnetometer) are presented. Applying the usual magnetometer electronics we have substituted the analogue section by a digital processing unit (DPU). The 2f(0) signal is digitized at its second harmonic and mean values are online phase-sensitively calculated. Based on this development we present a completely redesigned magnetometer experiment for applications on planetary surfaces. Sensor and electronics including serial interface have to be in one housing, its weight is less than 150 g and the number of electrical connections is limited to four (power lines + serial link). Applications for the digital magnetometer on Earth are also discussed.

Referring to the magnetometer experiments onboard the Mars-96 balloon, and the magnetometer on EQUATOR-S we present the development of fluxgate magnetometers in the MPE-A Berlin for application on small satellites and balloons.