News | October 31, 2012
Cassini Significant Events 10/24/2012 - 10/30/2012
The most recent spacecraft tracking and telemetry data were collected on Oct. 31 by the Deep Space Network's 34 meter Station 55 at Madrid, Spain. Except for the Cassini Plasma Spectrometer, which is off, and the failed Ultrastable Oscillator, the Cassini spacecraft continues to be in an excellent state of health with all its subsystems operating normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at:
As planned, Cassini's S75 command sequence had no science observations to carry out while the Sun degraded the communications link. Instead, the spacecraft executed the innovative Propellant Gauging Test (PGT), which was described last week. On this planet, Sequence Implementation Process (SIP) teams worked on S77, S78, and S79; the last of these sequences of commands goes active next June.
Also this week, JPL hosted the 58th Cassini Project Science Group meeting of about 125 scientists, representing all of Cassini's science disciplines. Presentations included planning for the F-ring and proximal orbits, when in 2016 and 2017 Cassini's periapse will be brought near the F ring (just outside the main rings) and then will be lowered inside the D ring, right above Saturn's atmosphere. These, and all of Cassini's orbits of Saturn, are illustrated in this new image:
Wednesday, Oct. 24 (DOY 298)
The Sun-Earth-"Probe" (which of course is Cassini) angle (SEP) was at a minimum for this year, at 2.2 degrees from the center of the Sun's disk. Since the Sun subtends about half a degree, Cassini was separated by less than two degrees from the solar limb as seen from Earth.
Today was the U.S. deadline for the Cassini Scientist for a Day essay contest. Deadlines for other countries vary (there are 39 countries participating). One hundred seventy teachers in 36 states submitted a record number of essays written by 2,032 of their students in grades 5-12. Further information is available at this link:
Thursday, Oct. 25 (DOY 299)
The S76 final sequence approval meeting and command approval meeting took place today.
A news feature was released on the aftermath of the massive storm in Saturn's northern hemisphere. It appears here:
Friday, Oct. 26 (DOY 300)
This week, Realtime Operations (RTO) team engineers and a Science Planning and Sequence Team leader reviewed an update to the Cassini Anomaly Response Plan document. The new version of ground-based procedures is targeted to go into effect by the end of the year.
Saturday, Oct. 27 (DOY 301)
Commands for the second of two articulation calibrations of the Cosmic Dust Analyzer were uplinked today for execution on Monday.
Sunday, Oct. 28 (DOY 302)
Selected 70 meter and 34 meter antennas of the Deep Space Network (DSN) spent most of their daylight hours pointing close to the sun to track Cassini on four occasions this week.
Monday, Oct. 29 (DOY 303)
The week-long PGT finished its cooling cycle shortly after midnight, having generated high quality spacecraft thermal data for future analysis. The science instruments were powered back on, except for VIMS, which had been assigned to powered sleep mode for the PGT, and CAPS, which is currently not in use. Heaters were re-configured and attitude control was switched from thrusters back to reaction wheels. Cassini's Navigation Team is modeling the additional delta-V that resulted from thruster use during the week for its effect on the spacecraft's trajectory.
Mimas is "Dwarfed by Saturn" in an image featured today that is remarkable for its view of the main rings' dark side and their crisp shadows on the clouds in Saturn's southern hemisphere. It may be seen here:
Tuesday, Oct. 30 (DOY 304)
Cassini slowed to 7,314 kilometers per hour relative to Saturn as it passed through apoapsis, having reached 2.7 million kilometers from the planet, more than twice the distance of Titan's orbit. This marked the beginning of Cassini's 174th orbit since orbit insertion on June 30, 2004.
Using the DSN's Autorad capability, this week the RTO team and the S76 SIP Lead uplinked the remaining S76 Instrument Expanded Blocks, the S76 sequence itself, and some other utility commands. All were confirmed to be properly registered aboard the spacecraft.