At its plant in Campi Bisenzio (FI), Leonardo has built, in collaboration with INAF, the "JANUS" high-resolution camera for monitoring Jupiter's atmosphere and in-depth study of its three icy moons, Europa, Ganymede and Callisto, to search for environments believed to be capable of harboring life forms. JANUS is the only high-resolution camera on the JUICE mission, and its resolution is such that it can observe a tennis ball from 1 km away. A distinctive feature of JANUS is its wheel with 13 filters of different colors. Each filter will allow the JANUS eye to detect concentrations of different chemical elements: for example, red will be able to detect methane and yellow will see sodium. To keep JANUS's optics immobile and thus ensure image quality despite the stresses of launch and temperature changes, JANUS's mechanical and thermal design was developed to limit deformation to values less than one-tenth the thickness of a hair, making JANUS virtually undeformable. Leonardo is industrially responsible for the entire instrument with subsystem contributions from DLR in Berlin, CSIC-IAA in Granada and CEI-Open University in Milton Keynes.
For the "MAJIS" instrument, which is a French responsibility but made under a bilateral agreement between ASI and CNES, Leonardo built the hyperspectral optical head in Campi Bisenzio (FI) to observe and characterize clouds, ice and minerals on the surfaces of the three moons. It is a kind of flying laboratory the size of a bedside table for chemical and physical analysis from a few thousand kilometers away. Consisting of two instruments in one that collectively cover the visible to mid-infrared range, MAJIS is equivalent to having 1,016 cameras each capturing an image in a single color. By appropriately combining these images, it is possible to identify the minerals that make up the surface of solid bodies and the gases in their atmospheres, while also measuring their density, temperature, motions, and so on. In order to observe in the infrared, MAJIS is cooled down to -180°C by a special pair of radiators that allows it to "capture" the cold of deep space, without any energy consumption. However, to achieve this, it was necessary to thermally insulate the instrument from the rest of the much warmer probe. For example, "feet" (bipods) are used to lift MAJIS. These "feet" however thin were made and tested to support a force equal to the weight of a bus! With such thermal insulation, it would be possible to keep an icicle inside a lit oven for years without melting it. MAJIS was designed optically as a kind of "kaleidoscope," in which light travels along a complicated zig-zag path composed of 28 lenses and mirrors. This idea arose from the need to reduce the space between the light inlet and the focal plane, so that the required high performance could be achieved, but with the reduced volume established by the mission.
Then in the Leonardo factory in Nerviano (MI) came the JUICE photovoltaic panels, the largest ever made for an interplanetary mission, with a surface area of 85m2 and a total of about 24,000 cells to provide the electrical power needed at a distance of more than 750 million km from the Sun. These panels if orbiting Earth could power an entire apartment building, on Jupiter they will instead produce about 900 Watts, which is the energy used by a household appliance. In fact, the intensity of sunlight around Jupiter's orbits is only one-twenty-fifth when compared to that received on Earth. Thales Alenia Space (a joint venture between Thales 67 percent and Leonardo 33 percent) in Italy is responsible for the development, implementation and testing of RIME (Radar Sounder for Icy Moons Exploration), among the most important of the 10 instruments aboard the JUICE probe. This instrument is critical to the success of the mission because of its ability to directly detect the internal structure of the icy layers. RIME operates at a frequency of 9 MHz and uses a 16-meter antenna, made by Space Tech GmbH on behalf of Airbus Defence and Space. The Radar Sounder is capable of penetrating up to 9 km below the ice surface with a vertical resolution of up to 30 meters; therefore, it will be able to explore the internal structure of Ganymede, Callisto and Europa.
The University of Trento, which is responsible for the scientific aspects, is the interface to ESA. The development was funded by ASI, thanks to a contract with Thales Alenia Space, which designed and built the instrument, with some units provided by NASA/JPL. In addition to the RIME instrument, Thales Alenia Space built with the University of Rome La Sapienza, the KaT (Ka Translator), a key part of the 3GM (Gravity & Geophysics of Jupiter and Galilean Moons) instrument.
Thales Alenia Space also made key equipment for the JUICE probe platform itself: the Deep Space Transponder - DST, the High Gain Antenna - HGA, the High Attitude Accelerometer -HAA. Telespazio (a joint venture between Leonardo 67 percent and Thales 33 percent) is participating in the JUICE mission through its subsidiary Telespazio Germany, providing engineering and operational support to ESA's European Space Operations Center (ESOC). In particular, Telespazio engineers contributed to the preparation of the spacecraft with responsibilities in simulation activities and astrodynamics services. In addition, Telespazio Germany developed the operational simulator used by the mission's Flight Control Team, which was used in the launch preparation phase.
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