Cassini Significant Events 07/21/10 – 07/27/10

The most recent spacecraft telemetry was acquired on July 26 from the Deep Space Network tracking complex at Canberra, Australia. 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, July 21 (DOY 202)

Three Instrument Expanded Block (IEB) files were uplinked to the spacecraft today in support of S62. After reviewing the memory readouts, the uplink team has verified that the files have been properly loaded into the solid-state recorder.

Thursday, July 22 (DOY 203)

The Command and Data Subsystem Flight Software (FSW) V10 Integrated Test Laboratory final end-to-end test took place July 20-22. This FSW load is scheduled to be uplinked on Aug. 11.

Commands were uplinked to the spacecraft today to clear the recent Solid State Power Switch (SSPS) trips, to reload Engineering Unit B, and to store the real-time end of sequence RWA bias commands for execution on DOY 211. Everything made it to the spacecraft (S/C) successfully. The S/C is fully recovered from both recent SSPS trips.

Friday, July 23 (DOY 204)

The background sequence for S62 was uplinked over DSS 25 earlier today. The files have been verified as properly received by the S/C and will start execution on 30 July (DOY 211).

Commands for the Composite Infrared Spectrometer (CIRS) FSW checkout were uplinked today and will begin execution on DOY 209. The activity will switch CIRS flight software to V6.0, perform a series of tests to check out the software, and then load new Instrument Expanded Blocks for use with the background sequence for the remainder of S61.

Port 1 products were due today as part of the S65 Sequence Implementation Process (SIP). The products will be merged July 26 and sent out to the flight team for review.

Saturday, July 24 (DOY 205)

On DOY 205, Cassini Radio Science (RSS) performed the orbit 135 Saturn atmospheric occultation experiment. This activity measured vertical profiles of electron density in the ionosphere, and of density, pressure, and temperature in the neutral atmosphere. X, S, and Ka band frequencies were used. The observation captured low southern latitudes. This range of low latitudes is not usually possible to sample because of ring interference. The rings are still nearly closed (i.e., nearly edge-on to Earth) at this time. The more nearly complete latitude coverage allowed for good characterization of the variability of the thermal structure of Saturn's atmosphere with latitude, hence better characterization of ongoing physical processes. The experiment was ingress-only and was covered by the Madrid complex using DSS-63 with S- and X-band support and DSS-55 with X- and Ka-band support. The experiment was completed as planned and data were collected at all three observation frequencies. The timing of the limb-track maneuver appears to have been exactly correct.

Sunday, July 25 (DOY 206)

Non-targeted flybys of Prometheus and Atlas occurred today.

Additional science observations included an Ultraviolet Imaging Spectrograph Saturn extreme ultraviolet / far ultraviolet observation involving slow scans across the visible hemisphere to form spectral images. The Visual and Infrared Mapping Spectrometer (VIMS) acquired data for a Saturn global dynamics mosaic for deep atmospheric studies, and an omiCet star-ring occultation. RADAR took data for a global map of Saturn. The Optical Remote Sensing teams continued the Titan cloud monitoring campaign. Magnetospheric and Plasma Science (MAPS) instruments performed periapse survey observations, and continued the magnetospheric boundaries campaign. With VIMS riding along, Imaging Science (ISS) looked for lightning on Saturn. ISS also observed the transit of Dione across Rhea, Prometheus across Janus, and other satellite observations as part of the ongoing satellite orbit determination campaign.

Monday, July 26 (DOY 207)

Today the Command Loss Timer value was set to 7 days. During sequence development for S61, the final DSN pass in the background sequence was trimmed to the point where no uplink capability remained. At this time the project is in the process of transitioning to DSN coverage of one pass every other day rather than the pass a day used in Prime and Extended Mission. If for some reason the pass on DOY 209 or 213 were to be lost, the project would exceed the existing limit for the CLT and invoke fault protection. Lengthening the CLT setting at this time reduces the chances of that occurring.

The MAPS science segment from July 26 to July 30 was dedicated to low latitude apoapsis observations to give the MAPS instruments an opportunity to acquire nearly complete and continuous measurements of Saturn's outer magnetosphere and magnetosheath. By doing this once every four to six months, the MAPS instruments will be able to observe Saturn's magnetosphere over a solar cycle from one solar minimum to the next, and investigate magnetospheric periodicities and how the Saturn kilometric radiation (SKR) period is imposed on the magnetosphere.

Tuesday, July 27 (DOY 208)

Titan Working Team and Orbiter Science Team integrated products for S66, covering orbits 143 through 146 in January 2011 through March 2011, were delivered today. The integrated products are in their final form and no re-integration is planned. The Sequence Implementation Process will kick off on Aug. 12. The instrument teams are currently working on the pointing designs for this sequence.

The Cassini-Huygens Analysis and Results of the Mission (CHARM) teleconference for July was held today. The topic: "Cassini Huygens Mission to Saturn Sixth Anniversary -- Part 2 - Mission Overview, Highlights of Saturn's Atmosphere, Interior and Rings."
A PDF of the presentation package may be obtained at:
http://saturn.jpl.nasa.gov/video/products/MultimediaProductsCharm/.
An audio recording of this presentation will be linked to the same location within a few days.