RSI (Radio Science Investigation). Shifts in the spacecraft's radio signals are used to measure the mass, density and gravity of the nucleus, to define the comet's orbit, and to study the inner coma. RSI will also be used to measure the mass and density of Siwa, and to study the solar corona during the periods when the spacecraft, as seen from Earth, is passing behind the Sun.
Principal Investigator: Martin Pätzold, Universität zu Köln, Cologne, Germany.
Last update: 9 October 2013