On Friday, April 14, 2023, at 2:14 p.m. (CEST), an Ariane 5 rocket will launch ESA's JUICE space probe into space from the Spaceport in French Guiana. After a long journey starting in July 2031, the "JUpiter ICy Moons Explorer" will study the giant gas planet Jupiter and its icy moons Ganymede, Callisto and Europa, whose thick ice hides watery oceans.
One of the 10 state-of-the-art scientific instruments on the probe is the so-called Submillimeter Wave Instrument (SWI) of the Max Planck Institute for Solar System Research. The Institute of Electrical and Optical Communications Engineering (INT) at the University of Stuttgart has designed a radiation-hard analog-to-digital converter for this instrument, which is a central element of the baseband receiver of a so-called chirp transform spectrometer. Using this spectrometer, SWI will study the Galilean moons and Jupiter's middle atmosphere and provide data for exploring possible habitable zones on Ganymed, Europa, and Callisto.
When designing the converters, the main consideration had to be the hard space radiation in the vicinity of Jupiter, which disturbs the sensitive electronics. High-energy radiation particles hit the integrated circuits and create electron-hole pairs, which can cause logical states ("zeros and ones") in the circuit to flip. This would cause the circuit to provide erroneous information. Radiation can even cause short circuits in the power supply (known as the latchup effect, a parasitic thyristor is switched through), which would cause the instrument to fail. Through circuitry tricks and a mask design adapted to the latchup, the analog-to-digital converter developed at INT could be hardened against these effects of space radiation.
