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Cassini was a space mission launched in 1997 to observe Saturn, its ring system and moons, a project of NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI), observing from Saturn orbit from 2004 to 2017. In addition to the orbiter, it carried a probe named Huygens that landed on Titan. The orbiter's primary mission lasted four years, followed by a two-year extension (to 2010, Cassini Equinox), a 6 1/2 year extension (Cassini Solstice), and a final 10-month mission (The Grand Finale) carrying out riskier research. It was purposefully destroyed by burning it Saturn's atmosphere on September 15, 2017, with the aim of eliminating further chance of biological contamination of the moons. The final orbits were very close to the rings and to Saturn's atmosphere, to view these from as close as possible. Instruments:
The radar included SAR, "Synthetic Aperture Radar Imager" which used the change of position of the spacecraft to simulate a larger aperture and produced detailed three-dimensional maps.
The Cosmic Dust Analyzer (CDA) measured velocity, direction, and chemical composition of incoming dust by electrical measurements of ions and electrons, both of the particle and of the results of the collision, and by mass spectrometry of the results. Through direction and by comparing the velocity with escape velocities of the solar system, the planet, and nearby moon, it can be determined whether the dust grain is extra-solar, etc. As of 2016, thirty six extra-solar dust grains had been reported (i.e., with velocity much higher than the Sun's escape velocity), which showed an unexpected degree of uniformity.
Huygens landed successfully on Titan in 2005, transmitting data during its descent and for 90 minutes on the surface (including an image), as per its design and expected battery life. Instruments included: