Cassini Significant Events 06/02/10 – 06/08/10

The most recent spacecraft telemetry was acquired on June 8 from the Deep Space Network tracking complex at Goldstone, California. The Cassini spacecraft is in an excellent state of health and all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at http://saturn.jpl.nasa.gov/mission/presentposition/.

Thursday, June 3 (DOY 54)

Non-targeted flybys of Helene, Calypso, Pandora, Tethys, and Rhea occurred today.

Two new papers based on data from Cassini scrutinize the complex chemical activity on the surface of Saturn's moon Titan. While non-biological chemistry offers a probable explanation, some scientists believe these chemical signatures bolster the argument for a primitive, exotic form of life or precursor to life on Titan's surface. According to one theory, the signatures fulfill two important conditions necessary for a hypothesized "methane-based" life. One key finding comes from a paper online now in the journal Icarus that shows hydrogen molecules flowing down through Titan's atmosphere and disappearing at the surface. Another paper online now in the Journal of Geophysical Research maps hydrocarbons on the Titan surface and finds a lack of acetylene. For the full details of this release link to: http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20100603/.

Friday, June 4 (DOY 155)

Having been closed on June 2 for dust hazard avoidance, the main engine cover was reopened today, completing the 60th in-flight cycle of the cover.

Saturday, June 5 (DOY 156)

Today Cassini flew by Titan at an altitude of 2,044 km, and a speed of 5.9 km/sec. Closest approach occurred at approximately 02:26 SCET – or June 4, 8:43 pm Pacific Time - and latitude 87 degrees N. During the T-69 flyby the Visual and Infrared Mapping Spectrometer (VIMS) was prime at closest approach and observed the northern lake region. A mosaic of Kraken Mare may be obtained if the north polar hood, which recently vanished, does not reappear before the flyby. A mosaic of an area north of Adiri was obtained at a resolution of 10 kilometers per pixel.

RADAR performed radiometry and scatterometry observations over Titan. The Magnetometer explored the edge of the north lobe of Titan's magnetic tail. The Magnetospheric Imaging Instrument measured the energetic ion and electron energy input to the atmosphere of Titan, giving good opportunities for measurement of energetic neutral atoms. The Radio and Plasma Wave Science instrument measured thermal plasmas in Titan's ionosphere and surrounding environment, searched for lightning in Titan's atmosphere, and investigated the interaction of Titan with Saturn's magnetosphere.

Imaging Science (ISS) acquired a full-disk mosaic of northwestern Adiri and rode along with VIMS during and after closest-approach to observe parts of Titan's anti-Saturnian hemisphere from the north pole to the equator. ISS also rode along with VIMS to track clouds and will continue to monitor clouds and their evolution for an extra two days after the Titan encounter. The Composite Infrared Spectrometer (CIRS) continued mapping seasonal temperature and composition effects. The Ultraviolet Imaging Spectrograph (UVIS) obtained an image cube of Titan's atmosphere at extreme and far ultraviolet wavelengths by sweeping its slit across the disk. These cubes provide spectral and spatial information on nitrogen emissions, H emission and absorption, absorption by simple hydrocarbons, and the scattering properties of haze aerosols. This is one of many such cubes gathered over the course of the mission to provide latitude and seasonal coverage of Titan's middle atmosphere and stratosphere. The Titan 69 flyby page is located at: http://saturn.jpl.nasa.gov/mission/flybys/titan20100605/.

Monday, June 7 (DOY 158)

Over the last three days Radio Science performed operations readiness tests in preparation for Saturn occultation observations on Jun. 18.

Following a very accurate Titan flyby last Friday, the cost of cancelling Orbit Trim Maneuver (OTM) #251 and making the entire Titan 70 correction at OTM-252 is only 29 mm/sec. As a result, OTM-251, scheduled for execution today, has been cancelled and the working meetings for OTM-252 moved earlier by one day. An early uplink for that maneuver is also being considered.

A week-long series of presentations and discussions at the 51st meeting of the Cassini Project Science Group begins today. With the start of the Solstice Mission right around the corner, topics will focus on the transition between missions.

Files for the third and final input port for S63 were delivered as part of the Science Operations Plan (SOP) process. The products will be handed off to Uplink Operations on June 17 to be used in final sequence development. S63 is the last sequence in the Equinox Mission, and the last to use the SOP process.

Titan Working Team and Orbiter Science Team integrated products for S65, covering orbits 141 through 143 in November 2010 through January 2011, were delivered today. The integrated products are in their final form and no re-integration is planned. The Sequence Implementation Process – a new process developed for XXM where the old Science Operations Plan and Science and Sequence Update processes have been streamlined and combined – will kick off on July 8. At this time instrument teams are working on the pointing designs for this sequence.

Tuesday, June 8 (DOY 159)

In addition to Titan observations, science this week included a number of CIRS equinox baseline observations. ISS, CIRS and VIMS took data for a rings movie and jointly observed Pandora during a relatively close fly-by at an altitude of 97,166 km. VIMS observed a rings occultation of the star Omicron Seti (Mira). ISS performed a propeller search in the A-Ring and all four Optical Remote Sensing Instruments observed Rhea during another nontargeted flyby.