Rosetta (ICA, LAP)

The European Space Agency (ESA) launched its spacecraft Rosetta on 2 March 2004 from Kourou, in French Guiana. It reached its target, the comet 67P/Churyumov-Gerasimenko, in 2014 with two instruments from IRF on board. 

Illustration: Artist’s impression of Rosetta and photograph of the comet’s nucleus (ESA)

For more than two years, Rosetta followed the comet in its orbit around the sun. IRF had two instruments on board: an ion mass spectrometer (ICA) from IRF in Kiruna and two Langmuir probes (LAP) from IRF in Uppsala. The task of both instruments was to study the partially ionized gas and the dust particles flowing from the comet nucleus (4 km in diameter) when it was heated by the sun.

Previous attempts to explore comets, such as ESA’s probe Giotto to the comets Halley and Grigg-Skjellerup, have been made during fast flybys. Rosetta travelled around Churyumov-Gerasimenko at a speed of just a few metres per second, giving unique opportunities for scientific measurements over a long period and from very close range.

Eleven instruments in total

The space probe spent 31 months in hibernation during the last part of the ten-year trip to the comet, but on 20 January 2014, ESA managed to resume contact with it. After the necessary health check-up, the eleven instruments (including IRF’s two) were switched on and could begin studying the comet.

After that the scientists followed from up close how the comet developed when it first swept further and further into the Solar System and then went out again. Rosetta’s mission was terminated with a controlled crash landing on the comet’s nucleus on 30 September 2016. The IRF’s instruments were on until the very end and the last measurements we have are as close as 200 metres from the comet’s surface. It was then more than 20 years since we started working on the project, and the analysis of the measurements will continue for many years more.

IRF instrument:
RPC-ICA (Rosetta Plasma Consortium – ion mass spectrometer, ICA), Principal Investigator: Hans Nilsson
RPC-LAP (Rosetta Plasma Consortium – Langmuir Probe, LAP), Principal Investigator: Anders Eriksson


Scientific information: Assoc. Prof. Hans Nilsson, tel. + 46-980-79127, (ICA)
Scientific information: Dr Anders Eriksson, tel. + 46-18-471 5945, (LAP)
Technical information (ICA): Herman Andersson, tel. + 46-980-79034,

Created by Annelie Klint Nilsson at

Last modified by Annelie Klint Nilsson at