Cassini Significant Events for 04/04/07 - 04/10/07

Cassini Significant Events for 04/04/07 - 04/10/07

The most recent spacecraft telemetry was acquired on Monday, April 9, from the Goldstone tracking complex. 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” web page located at

Wednesday, April 4 (DOY 094):

Using Saturn to provide the necessary target data, the Composite Infrared Spectrometer (CIRS) has been performing a weeklong checkout exercise of its new Version 5 instrument flight software. However, due to a data outage during a pass over DSS-14, CIRS was unable to obtain the results from part of its regression testing. A mini-sequence will be sent to the spacecraft on April 12 that will allow the instrument team to re-run the test and acquire the remaining data. After the test, CIRS returned to the previous V4.03 operational flight software.

Today Science Planning hosted a review of the Extended Mission Integration Guidelines and Constraints document. The purpose of this document is to provide the science target working teams and orbiter science teams with integration rules that will reduce the workload required to implement the integrated science plan. This meeting provided the opportunity for the science instrument teams and any other members of the Cassini Flight Team to recommend additional constraints for this document.

For the prime mission, the flight team had an advance-planning period that allowed for early development and integration of the tour sequences to be flown on-board the spacecraft. In some cases, these sequences have been in the archive for years waiting for the next step in the development cycle. For extended mission, this period is reduced to months. There is no advance planning period. As a result, processes are being combined and streamlined to allow for quality development in a much shorter period of time.

Thursday, April 5 (DOY 095):

All Teams and Offices supported the Cassini Monthly Management Review.

Friday, April 6 (DOY 096):

There’s a new video feature debuting on the JPL web pages today. The new monthly feature, called “What’s Up”, will highlight an astronomical viewing opportunity everyone can enjoy, usually even without a telescope, and usually in the most light polluted sky.

This month’s planet and mission tie-in is Saturn and Cassini. Saturn is a fantastic target even in the urban jungles. The moon rises from near Venus on April 21 through April 25, when the moon is above Saturn. Most of the images in the video came from amateur astronomers in the Saturn Observation Campaign. The video is here on the JPL home page:

On the JPL Education Gateway page you can download the sky chart which will show you where to find Venus and Saturn, and watch the crescent moon rise in between the two planets later this month. Go to:

Saturday, April 7 (DOY 097):

Orbit Trim Maneuver (OTM) 103 was performed today. This is the approach maneuver setting up for the Titan 28 encounter on April 10. The reaction control subsystem (RCS) burn began at 2:59 PM PST. Telemetry immediately after the maneuver showed the burn duration was 25.9 seconds, giving a delta-V of 0.033 m/s. All subsystems reported nominal performance after the maneuver.

Monday, April 9 (DOY 099):

Back on March 5, it was reported that a meeting had been held to discuss Radio and Plasma Wave Science (RPWS) whistler observations in future prime mission sequences. With only nine possible opportunities remaining for this activity, RPWS was very interested in seeing if the activity could be accommodated. The first of these RCS activities executed as planned today. RPWS acquired nearly four hours of plasma wave observations with the reaction wheels turned off so that the observations were not contaminated by electrical interference from the wheels. The primary reason for acquiring these data is to look for signals characteristic of lightning called whistlers, but other low frequency signals can also be studied in this configuration without being masked by interference. Searching through the acquired data for the seconds-long whistlers is a lengthy process; hence, it is not yet known if any of these were captured. It is clear, though, that some very interesting data probably related to Saturn’s auroras were acquired and will be of great interest.

Tuesday, April 10 (DOY 100):

Today Cassini flew by Titan today at a speed of 6.2 km/sec, and an altitude of 990 km for the T28 flyby. Science for the encounter included RADAR scatterometry, altimetry, and Synthetic Aperture Radar (SAR) observations of Titan’s surface as the hunt for lakes continues. Among the new parts of familiar terrain to be imaged is the “other side” boundary of the ‘black sea’, which could tell scientists more about its size. Additionally, the radar team has pointed this pass slightly southward so that it will align with a future altimetry flyby planned for May 12. Additional observations provided an opportunity for the Optical Remote Sensing instruments to image the night side of Titan. Imaging Science Subsystem took observations for lightning and aurora, Visual and Infrared Mapping Spectrometer did cloud mapping, and the Ultraviolet Imaging Spectrograph took data for an ultraviolet mosaic.

Astronomy Picture of the day today featured a not often seen view of the underside of Saturn.

Wrap up:

Check out the Cassini web site at for the latest press releases and images.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. JPL designed, developed and assembled the Cassini orbiter.