Event Archive

• 25. Feb., 2006-056/057
  CDA performed a scan through the dust RAM direction of the ring particles between 8 and 11 Saturn radii distance in the outer E ring close to the ring plane. This rocking mode allows the determination of the dynamical properties of Saturn's E ring particles: Which inclinations and eccentricities do the particles have?
• 26. Nov., 2005-330
  Cassini passed the moon Rhea and CDA detected a population of bigger particles in the vicinity of this moon.
• 5. Sep., 2005-248T10:38
  Cassini is close to Saturn and flys through the outer edge of Saturn's G ring at 2.9 Saturn radii distance. The High Rate Detector (HRD) counted many impacts and one large particle with a size of more than 20 microns was detected on the big foil.
• 14. July, 2005-195T19:55
  Cassini encountered the moon Enceladus. Enceladus has a diameter of 500 km and Cassini's closest approach occured at an altitude of 172 km. The Dust Analyzer was sensitive for particles during the flyby. The highest impact rate occured almost two minutes before the closest approach.
  The results show, that the ice geysers and ice volcanoes at the south pole of Enceladus are the main source for micrometer sized grains of Saturn's E ring.
  Read the full story about Enceladus here (German press release, March 2006).
• 30. May, 2005-150
  The Cosmic Dust Analyzer performed a Flight Software Update. The new version 10.0 includes a sophisticated classfication scheme using 27 counters instead of 20 until today.
• Mar 2005 - Day 068
  The Cassini spacecraft performed a special observation called "rocking". During this mode the CDA instrument crossed the dust RAM direction approx. every 15 min. This mode allows the determination of the dynamic properties of ring particles (eccentricity/inclination).
  CDA measured mass spectra of high speed (unbound) particles of non-common composition. The particles in the E ring are normally water ice, but these particles show clear mineral (Mg-Si-Fe) features. A special sequence of those spectra were measured at a distance of 6-7 Rs directly in the ring plane.
  A further "rocking" mode is planned on day 88.
• Feb. 2005
  The CDA detector measured negative electrical potential on dust particles. The distance to Saturn was approximately 3.6 Saturn radii (1 Rs=60330 km). Further away from Saturn, CDA detected positively charged particles with primary charges above 10 Femtocoulomb! This charge is the highest detected charge on a dust particle every measured in the solar system.
• Feb. 17, 2005 (DOY 048), 03:30h
  Cassini crossed the dense E ring and flew by at the moon Enceladus. The Enceladus surface is permanently bombarded by dust particles in the E ring. These impacts release further material and Enceladus acts as the main source of the water ice particles in the E ring. The CDA instrument measured a very high dust flux in the vicinity of Enceladus and the HRD detected many thousand impacts on its 50 cm^2 detector surface. The flyby occured at an altitude above the surface of about 1200 km.
• Jan. 15, 2005
  CDA is switched on after the Huygens mission. CDA performs outstanding measurements during the ring plane crossing on Jan 16. The High Rate Detector monitors bigger particles in the E ring (>2 micrometer).
• Jan. 14, 2005
  Huygens performs unique measurements of Titan's atmosphere. The CDA instrument is switched off in order not to disturb any Huygens activities.
• Dec. 25, 2004
  The Huygens probe is relased
• Dec 2004, DOY 350
  Ring Plane Crossing of Saturn's E ring. The CDA instrument detected many thousand impacts. The Spacecraft perform a roll about the z axis and CDA sweeps through the dust RAM direction many times. During its approach to Saturn, an increased dust flux was detected well outside the known E ring: between 9 and 19 Saturn radii. Is the E ring much larger than assumed?
• Nov 2004
  The Cassini spacecraft entered the inner system of Saturn and crossed the ring plane at 8 Rs on day 302. CDA measured an increased dust population inside Titan's orbit, far outside the well know E-ring which is defined between 3 and 8 Rs. The latitude reached values above 10 deg at distances of 7 Rs, even at those locations an increased dust flux was detected.
  During this phase, CDA measured the composition of E-ring particles with the integrated ToF mass spectrometer. A preliminary analysis confirms water ice particles with submicron sizes.
• Aug 2004
  Further detection of Saturn dust streams particles (speed > 100 km/s). The dust jettisoned by the Saturnian system were seen on the days 208, 210 and 212-215. Many impacts generated a time-of-flight mass spectrum for the compositional analysis.
• 3rd July (2004-185)
Detection of a 10 micron sized particle with the highest electrical primary charge ever seen on a dust particle in interplanetary space! The primary charge was in the order of 9.5 fC. At this time, Cassini was already at 25 Rs and at a latitude of -13 deg.
• 2nd July
  CDA detected micron sized dust particles in the Saturn environment outside the known rings. The impacts occured at a Saturn distance of 13 Saturn-Radii and a latitude of -13 deg.
• 1st July 2004
  Cassini-Huygens arrives at Saturn. After a successful orbit insertion maneuver Cassini enters the first orbit around Saturn. Cassini-Huygens will orbit 78 times within the next 4 years around Saturn.
  The CDA instrument was in a safe state since day 172 and switched back to a measurement state in the afternoon of day 183.
• 11th June 2004
  Cassini-Huygens flies by at the outer moon Phoebe. The CDA instrument tried to find dust particles sputtered off by the surface of Phoebe for a limited time of about 10 minutes. No dust particles were found by CDA during the close Phoebe fly-by.
• May 2004
  Since a couple of weeks, CDA detects sporadic dust particle impacts with a much higher rate than during cruise. These particle show similar properties like the dust stream particles of the Jupiter-system. The particles appear only partly from the Saturn direction but they reach Saturn-off angles as high as 100 degrees. The particles are faster than 100 km/s and are below 50 nm in diameter. These "Saturn dust streams" are released in the Saturn system and are accelerated by the corotating electric field of Saturn. Some of those accelerated particles have enough energy to leave the Saturn system to enter interplanetary space.
• April 2004
  An analysis of the early cruise data of CDA showed the detection of interstellar dust between Venus and Earth orbit!
• 2003
  During cruise between Jupiter and Saturn the dust impact rate is well below 1 particle per week. The instrument performs excellent and the team prepares updates for the onboard flight software.
• 2001
  CDA detects Jovian dust stream particles beyond Jupiters orbit up to distances as far as 200 million km away from Jupiter.
• 30 Dec 2000
  Cassini-Huygens flies by Jupiter. A combined measurement of the Galileo and Cassini dust instrument analyzes the flux of Jovian dust streams at two distances from Jupiter (Galileo in the inner Jovian system, and Cassini at 140 Jupiter-Radii). The results show a significant higher flux at the measurement position of Cassini! This high rate measured far away from Jupiter is explained by the higher sensitivity of the CDA instrument. CDA can therefore detect particles which are not seen by the Galileo instrument.
• Sep/Dec 2000
  CDA detects the Jovian dust stream particles. CDA recored over 100 impact spectra showing a time-of-flight mass spectrum.
• June 2000
  CDA measures the charge of six interplanetary dust particles at solar distances between 1 and 2.5 AU. The amount of charges on the particles lies between 9000 and 50000 electrons. CDA can therefore confirm the theoretical and laboratory results of dust charging in space. CDA measured dust particles charge in space for the first time.
• Aug 1999
  Cassini flies by Earth. The CDA was switched off for safety reasons.
• Mar 1999
  The CDA instrument was switched on and starts measurements of interplanetary and interstellar particles. Although the data rate of Cassini is very low (1 8-hour pass every 2 weeks with 40 bps total), CDA can link science data back to Earth. Advanced methods in compression (wavelet) and processing (science data into housekeeping stream) allows CDA science measurements during cruise.
• Oct 1997
  Launch of Cassini-Huygens. The cover of CDA was released successfully 3 weeks after launch.