Rosetta is the first mission to orbit and land on a comet. After a cruise requiring 10 years, the Rosetta spacecraft will enter in orbit around the comet nucleus and separate itself in two parts: Rosetta Orbiter, that will perform remote inspections of the comet surface and tail, and Rosetta Lander, a probe that will land on the nucleus, to perform various scientific experiments and send result data to the Earth using the Orbiter as intermediate radio station.

Rosetta spacecraft
Rosetta spacecraft (photo: ESA)

Rosetta has been successfully launched from Kourou (French Guyana) on 2 March 2004, on board of an Ariane 5G rocket and is expected to reach the comet 67P/Churyumov-Gerasimenko by the year 2015.

Rosetta Lander
Rosetta Lander (photo: ESA)

Comets are small bodies with highly elliptical orbits that bring them close to the Sun and then far away, often beyond the orbit of Pluto. Their composition (up to now only revealed by spectroscopic analysis with telescopes) appears rich in frozen water and organic molecules.

Studying comets is important because they may have spread the chemical seeds for life through the solar system, by colliding with planets and delivering their load of water and essential molecular building blocks. The spectacular impact of the comet Shoemaker-Levy on Jupiter (July 1994) has shown that such collisions actually do happen. A way to test the hypotesis that a significant part of Earth's water has been provided by comets is to compare the Deuterium ratio of comet's and Earth's water. This is one of Rosetta Lander's tasks.

The SD2 subsystem
The SD2 subsystem (vertical white cylinder) mounted on a Rosetta Lander mock-up;
the drill tip is visible at the bottom (photo: Galileo Avionica)

I've been involved in both Rosetta Orbiter and Rosetta Lander projects.

On the Orbiter side, I worked as system engineer to the software requirements and interfaces definition for the Visual and Infrared Thermal Imaging Spectrometer (VIRTIS), that will take orbital images of the comet and its tail.

On the Lander side, I worked as software engineer and test manager for the Sample Drill & Distribution (SD2), a drill capable of penetrating the comet surface for extracting and analyzing cometary samples. The SD2 flight software and test software are completely written in Forth.