Cassini Significant Events 10/01/08 - 10/07/08
The most recent spacecraft telemetry was acquired on Oct. 7 from the
Deep Space Network tracking complex at Goldstone, California. 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/operations/present-position.cfm.
Wednesday, Oct. 1 (DOY 275):
The Cassini-Huygens Analysis and Results of the Mission (CHARM)
teleconference for September was held last week. The topic:
Cassini Composite Infrared Spectrometer (CIRS): Instrument, Operations,
and Science.
The Science Operations Plan kickoff meeting for the S49 sequence was held
today. Files to be delivered for the first port are due Oct.
23.
Thursday, Oct. 2 (DOY 276):
A non-targeted flyby of Tethys occurred today.
Orbit Trim Maneuver (OTM) #165 was performed today. This is the
periapsis maneuver setting up for the Enceladus 5 encounter on Oct.
9. The main engine burn began at 4:44 AM PDT. Telemetry immediately
after the maneuver showed the burn duration was 23.71 seconds, giving a
delta-V of 3.93 m/s. All subsystems reported nominal performance after
the maneuver.
The main engine cover was closed today at end of the OTM-165 prime window
for a dust hazard. It was reopened about 2.5 hours later.
This was cycle #46 for the cover.
Heading into Saturn periapsis, activity on-board the spacecraft has
increased. The day began with a short high resolution F ring stare
by the narrow angle camera. Meanwhile, the Magnetospheric and
Plasma Science (MAPS) teams collected data at increased rates. Of
particular note, the Radio and Plasma Wave Science (RPWS) instrument
performed a "whistler" activity. Whistler observations
are used to obtain wideband evidence of lightning whistlers which would
verify the existence of lightning already suspected from Saturn
Electrostatic Discharges (SED) and provide information on the electron
density along the field line to the source. After this, the spacecraft
turned to Earth to downlink the data and clear the SSRs in preparation
for receipt of periapsis data. The downlink was interrupted briefly
for OTM-165, the final deterministic maneuver before Enceladus 5.
Following the downlink, MAPS had prime pointing to observe the auroral
magnetosphere and Saturn Kilometric Radiation source region. MAPS
and Optical Remote Sensing (ORS) teams coordinated the pointing and
timing closely so that CIRS could observe Tethys as it was eclipsed by
Saturn. Finally, the last short activity of periapsis science was a
joint Ultraviolet Imaging Spectrograph (UVIS), Visual and Infrared
Mapping Spectrometer (VIMS), Imaging Science Subsystem (ISS), and CIRS
campaign to study the auroras at Saturn's poles.
Friday, Oct. 3 (DOY 277):
A non-targeted flyby of Titan occurred today.
The spacecraft was busy executing many short duration activities.
The first was ISS with another observation set in the campaign for small
satellite orbit determination. Next, the Cassini Plasma
Spectrometer (CAPS) took pointing control of the spacecraft for MAPS
instruments to collect enhanced survey data. After CAPS, the
spacecraft turned towards Earth to downlink science data. During
the downlink, Radio Science (RSS) performed an Operational Readiness Test
to demonstrate DSN and RSS preparedness to support the orbit 89 rings
occultation experiment on DOY 291. Following the downlink, CIRS took a
thermal scan of the rings. VIMS had the next activity, again
observing a stellar-ring occultation, this time of the outer A-ring
region. Afterwards, the full suite of ORS instruments observed
Mimas to collect additional longitudinal and phase angle coverage.
The day concluded with ISS taking another series of small satellite
orbital determination images plus one Titan cloud monitoring
image.
Monday, Oct. 6 (DOY 280):
Orbit Trim Maneuver (OTM) #166 was performed today. This is the
approach maneuver setting up for the Enceladus 5 encounter on Oct.
9. The reaction control subsystem burn began at 12:29 PM PDT.
Telemetry immediately after the maneuver showed the burn duration was
8.13 seconds, giving a delta-V of 14.96 mm/s. All subsystems reported
nominal performance after the maneuver.
The Oct. 9 flyby of Enceladus is the first of two to occur in
October. This is the closest flyby yet of any moon of Saturn,
at only 25 kilometers from the surface. The Oct. 31 flyby is farther out,
at 196 kilometers. During the Oct. 9 flyby, the on-board fields and
particles instruments will venture deeper into the plume than ever
before, directly sampling the particles and gases. The emphasis here is
on the composition of the plumes rather than imaging the surface.
On Oct. 31, the cameras and other optical remote sensing instruments will
be front and center, imaging the fractures that slash across the moon's
south polar region. For more information link to:
http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=874
The NASA blog is active once again for the E5 flyby on Oct. 9. To
participate, link to:
http://blogs.nasa.gov/cm/blog/enceladus
Closest approach will occur on Oct. 9 at 1:30 PM Pacific Time. Just
29 seconds after closest approach, Cassini will fly directly over the
South Pole at an altitude of 339 kilometers. The first data will hit the
ground at about 2:30AM Pacific Time on Oct. 10.
Tuesday, Oct. 7 (DOY 281):
The main engine cover was closed today at the end of the OTM-166
backup window for a potential dust hazard as part of the Enceladus 5
flyby on Oct. 9. It will be opened after the flyby on Oct.
10. This will be cycle #47 for the cover.
Spacecraft Operations (SCO) hosted the S50 Engineering Activities Review
today. The objective of the meeting is for SCO and Navigation to take a
long look ahead - S50 executes in May of 2009 - and determine whether
there are any periods or activities where contingency planning might be
appropriate.
As part of the sequence development process for S46, the RADAR team
requested that their designs for the Titan T48 and T49 flybys be
simulated in the ITL. The simulations will begin today and continue
through the weekend.
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