ROSETTA is an ESA science mission to the comet 67P/Churyumov-Gerasimenko. The mission is named after the Rosetta stone, which was the key to unlocking the secrets of ancient Egyptian hieroglyphics. One of the missions prime objective is to investigate the origin of the Solar System by studying the origin of comets. After being launched in March 2004 the spacecraft will travel into deep space during the ten-year trek across the Solar System, more than five times Earth’s distance from the Sun (5.25 Astronomical Units, AU) away. After entering orbit around Comet 67P/Churyumov-Gerasimenko in 2014, the spacecraft will release a small lander onto the surface and spend the next years orbiting the comet, observing what happens as the icy nucleus approaches the Sun.
The instrument package Rosetta Orbiter Spectrometer for Ion an Neutral Analysis (ROSINA) consists of two mass spectrometers and one pressure sensor, designed to analyze the composition of cometary neutral gases and ions. All three sensors are controlled and their data is processed by a common Data Processing Unit (DPU), which was completely developed and assembled at IDA. The required processing is performed in software by a 32-bit Digital Signal Processor (DSP, TSC21020F) with a fast SRAM memory (11 Mbytes). To provide highest reliability, all DPU functions are duplicated and organized into two independent (cold redundant). The software is based on a real-time multitasking operating system that provides preemptive, event-driven scheduling of dynamically prioritized tasks with synchronization and communication facilities.