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NASA Cassini Significant Events 01/13/10 - 01/19/10

Status Report From: Jet Propulsion Laboratory
Posted: Friday, January 29, 2010

image The most recent spacecraft telemetry was acquired on Jan. 19 from the Deep Space Network tracking complex at Madrid, Spain. 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/.

Wednesday, Jan. 13 (DOY 013)

The Science Operations Plan process (SOP) for S61, the first of the "bridge sequences," kicked off today.

Back in 2007, prior to NASA approval of the Equinox Extended Mission (XM), it was necessary to begin development for that mission so that if approved, execution could proceed on schedule. At that time, it was decided to leave the final three sequences of XM indefinite and firm them up at a later time. Now that Cassini is waiting for approval of an Extended Extended Solstice Mission (XXM), these final sequences of XM, S61, S62, and S63 have been defined, segmented and designated the bridge sequences to bridge between XM and the proposed XXM. Should XXM be approved, S64-S67 would become the "transition sequences." To meet a goal of a 50 percent reduction in workforce, the Sequence Integration Process (SIP) was developed for XXM to replace the SOP and Science and Sequence Update (SSUP) processes. Between S64 and S68, the development process was shortened from 24 weeks to 20, and sequence execution extended from 5 to 10 weeks. These three changes were part of what enabled the Project to drop from six parallel processes to three, and thus achieve the target reduction in workforce.

Thursday, Jan. 14 (DOY 014)

Files were due today from all participating teams for the second input port of the S60 SOP process. The files will be merged Monday and products sent out for review that same day.

The S57 final sequence approval meeting was held today. The background sequence will go up to the spacecraft on Tuesday, Jan. 19, and will begin execution on Saturday, Jan. 23.

The Huygens probe parachuted down to the surface of Titan exactly five years ago today on Jan. 14, 2005, providing data that scientists are still building upon today. The Huygens probe, built and managed by the European Space Agency, was bolted to Cassini and rode along during the nearly seven-year journey to Saturn. Huygens' descent marked the first and only attempt to land a probe on another world in the outer solar system. For the complete story link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20100114/ .

Friday, Jan. 15 (DOY 015)

Orbit Trim Maneuver (OTM) #233 was performed today. This was the cleanup maneuver from the Titan 65 encounter on Jan. 12. The main engine burn began at 10:14 PM PST. Telemetry immediately after the maneuver showed a burn duration of 13.33 seconds, giving a delta-V of 2.26 m/s. All subsystems reported nominal performance after the maneuver.

Monday, Jan. 18 (DOY 018)

All Instrument Expanded Block files for S57 were uplinked to the spacecraft and verified over the weekend.

Today was a calibration day for some of the instruments. The Composite Infrared Spectrometer (CIRS) started off with an activity called a "Scattered Sunlight Test." This activity quantified the effect of ring particle impacts on the mirror performance by monitoring scattered infrared solar radiation as a function of offset angle from the sun. RADAR was next with a Radiometric Microwave Sources Calibration. This activity was performed by pointing the RADAR antenna, co-aligned with Cassini's high gain antenna, towards the Sun, Saturn, and various other known microwave sources.

Tuesday, Jan. 19 (DOY 019)

CIRS performed a noise test today. Files were uplinked last Thursday to patch CIRS flight software and collect science data to see if changes in the software would eliminate internal instrument generated noise. At the end of the test the flight software was patched back to the current version.

A hydrazine and deltaV consumables update was given today by Mission Planning at the Mission Planning Forum. Mission Planning, the Spacecraft Office, and the Program Office monitor these two consumables very carefully to ensure enough remains to carry out the mission as designed. At the presentation a discussion was held on how to re-evaluate as-flown usage and strategically plan for future sequences.

This week as Cassini approached Saturn apoapsis, observations that took advantage of the wide special coverage provided by the large distance from Saturn were common. One of these observations, the Ultraviolet Imaging Spectrograph "apo-mosaic", performed several times throughout the week, produced mosaic scans of Saturn's magnetosphere.

Additional observations included Imaging Science monitoring of Titan, a Satellite Orbit Campaign, and imaging of the mutual transit of Epimetheus across Janus. These "mutual events", as they are called, help determine the orbits for both objects. The Cassini Plasma Spectrometer was prime during a period of Saturn magnetospheric measurement, and CIRS pointed towards several infrared stars as part of a long-term effort to monitor them.

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