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Cassini Significant Events 02/24/16 – 03/01/16

Cassini is orbiting Saturn with a period of 23.9 days in a plane inclined 21.9 degrees from the planet's equatorial plane. The most recent spacecraft tracking and telemetry data were obtained on March 1, using the 70-meter diameter Deep Space Network station in Australia. The spacecraft continues to be in an excellent state of health with all of its subsystems operating normally except for the instrument issues described at http://saturn.jpl.nasa.gov/news/significantevents/anomalies .

After Cassini "stole" a little of Titan's orbital momentum during the most recent encounter, T-117 on Feb. 16, the spacecraft found itself being propelled, as planned, to a higher apoapsis altitude than it has seen in almost a year. As of Friday it had climbed to a distance of more than 2.8 million kilometers from Saturn.

Back on Earth, Friday happened to be the deadline for the "Cassini Scientist for a Day" contest. The Outreach team had received 462 essays from students around the world in grades 5 through 12. Winners, selected by members of the flight team, will be announced in May.

Wednesday, Feb. 24 (DOY 055)

Cassini's Imaging Science Instrument (ISS) completed a 30-hour observation of Saturn's small, irregular moon Skoll, which was described last week. After this, the spacecraft turned to point its high-gain antenna towards Earth and began playing back the telemetry data from this and other observations. One of the 34-meter diameter Deep Space Network stations in Spain was on hand for 8.5 hours to set up and receive the data. It also provided an uplink to carry commands and ranging signals, and to supply a stable radio frequency reference for accurate tracking and navigation.

Thursday, Feb. 25 (DOY 056)

ISS turned to examine the space near Saturn for a 60-minute observation in the satellite orbit campaign, looking for small objects in that region. As soon as this was done, the Composite Infrared Spectrometer (CIRS) began a 23-hour long observation of Saturn’s atmosphere, measuring the temperatures in the upper troposphere and tropopause; the Visible and Infrared Mapping Spectrometer (VIMS) rode along.

Friday, Feb. 26 (DOY 057)

Taking advantage of its increased distance from Saturn today, the Cosmic Dust Analyzer (CDA) began nearly 34 hours of observing exogenous dust. These observations improve statistical sampling to help scientists understand the dust flux into the Saturn system, and thus the age of Saturn’s rings.

Late in the day during CDA's activity, Cassini passed through apoapsis, which marked the start of Saturn orbit #233. The spacecraft had slowed to 6,225 km per hour with respect to the planet.

Saturday, Feb. 27 (DOY 058)

Cassini's final 10-week command sequence, S101, will begin executing in 500 days from today.

Sunday, Feb. 28 (DOY 059)

After CDA finished sampling exogenous dust, ISS CIRS and VIMS spent 90 minutes on a Titan monitoring observation while the planet-like moon was about 3.9 million km away. Next, ISS made another 60-minute satellite orbit observation near the planet. Finally, CIRS stared at the sunlit side of Saturn's A ring for ten hours to study ring particle composition; VIMS rode along.

Monday, Feb. 29 (DOY 060)

ISS began a 30-hour observation of Saturn's irregular moon Ijiraq. Named after a creature in Inuit mythology, this very dark-surfaced object is about ten km in diameter, and occupies an inclined orbit that reaches as far as 14.6 million km from Saturn.
An image featured today captured Saturn's moons Tethys and Janus, with rings in the background.

Tuesday, March 1 (DOY 061)

On four occasions during the week, when the optical instruments were pointing at or near Saturn, ISS made two-minute Saturn storm-watch observations; VIMS rode along with two of them. Also this week, the Deep Space Network communicated with and tracked Cassini on five occasions, using its stations in Spain, California and Australia. A total of nine individual commands were uplinked, and about 1,160 megabytes of telemetry data were downlinked and captured at rates as high as 124,426 bits per second.

This illustration shows Cassini's position on March 1: http://go.nasa.gov/1OdN9AL . The format shows Cassini's path over most of its current orbit up to today; looking down from the north, all depicted objects (except the background stars of course) revolve counter-clockwise, including Saturn along its orange-colored orbit of the Sun.