In October 1997 a 5.6 tonne spacecraft called Cassini was launched from Cape Canaveral on a mission to investigate the Saturnian system. This joint ESA / NASA / ASI mission, named after Giovanni Domenico (later Jean-Dominique) Cassini, has investigated Venus, Jupiter and interplanetary space on its way to Saturn, around which it went into orbit on 1 July 2004, becoming the first ever artificial satellite of Saturn.
The mission comprised two principle components. The main component is the Cassini Orbiter, with an array of instruments to explore the Saturnian system. The second component was the Huygens lander which on the 14th January 2005 successfully entered the atmosphere of Titan (named after 17th Century Dutch astronomer Christiaan Huygens, who discovered Titan) and descended to its surface returning a wealth of information about this mist-shrouded planet.
The PSSRI has been involved in three experiments on the mission.
Cosmic Dust Analyser: On board the Cassini orbiter, this sensor is a dust detector designed to sample and measure the dust particle population around Saturn and in interplanetary space. PSSRI has a strong involvement with this Max Planck Institute for Nuclear Physics, Heidelberg-led instrument – with major contributions including calibration using a hypervelocity impact facility at the University of Kent (now relocated to PSSRI) and interpretation of the wealth of data that has been returned over the years of successful operation. The data allows us to determine what the dust is made of, and this will work in conjunction with measurements of particle size, mass, charge, and orbital trajectory to give data of unprecedented detail.
Surface Science Package: This is a suite of nine sensors that has been designed to record many properties of the probe's landing site and (during descent) of Titan's atmosphere. PSSRI lead the international consortium that designed and built this complex instrument. The principle instrument was an external accelerometer which measured the force with which a sensing 'spike' stuck the ground, and the resulting data revealed the physical properties of the pebble covered “soil” of the landing site.
Huygens Atmospheric Structure Instrument: The group has also contributed the accelerometry sub-system (ACC) to the Huygens Atmospheric Structure Instrument (HASI). This instrument monitored the motion of the probe during entry, descent and after landing, including the entry phase, and helped determine the density profile of Titan's upper atmosphere.
Cosmic Dust Analyser - now on-board the Cassini orbiter